WorldWideScience

Sample records for dynamical heavy-quark recombination

  1. Heavy quark dynamics in QCD matter

    Science.gov (United States)

    Das, S. K.; Scardina, F.; Plumari, S.; Greco, V.

    2017-01-01

    Simultaneous description of heavy quark nuclear modification factor RAA and the elliptic flow v 2 is a top challenge for all the existing models. We highlight how the temperature dependence of the energy loss/transport coefficients is responsible for addressing a large part of such a puzzle along with the full solution of the Boltzmann collision integral for the momentum evolution of heavy quarks in the medium. We consider four different models to evaluate the temperature dependence of drag coefficients of the heavy quark in the QGP. We have also highlighted the heavy quark dynamics in the presence of an external electromagnetic field which induces a sizable heavy quark directed flow, v 1(y), that can be measurable at LHC.

  2. Heavy quark dynamics in QCD matter

    CERN Document Server

    Das, Santosh K; Plumari, Salvatore; Greco, Vincenzo

    2016-01-01

    Simultaneous description of heavy quark nuclear suppression factor $R_{AA}$ and the elliptic flow $v_2$ is a top challenge for all the existing models. We highlight how the temperature dependence of the energy loss/transport coefficients is responsible to address a large part of such a puzzle along with the the full solution of the Boltzmann collision integral for the momentum evolution of heavy quark. We consider four different models to evaluate the temperature dependence of drag coefficients of the heavy quark in the QGP. We have also highlighted the heavy quark dynamics in the presence of an external electromagnetic field which develops a sizable heavy quark directed flow, $v_1(y)$, can be measurable at LHC.

  3. Dynamical heavy-quark recombination and the non-photonic single electron puzzle at RHIC

    CERN Document Server

    Ayala, Alejandro; Montano, Luis Manuel; Sanchez, G Toledo

    2009-01-01

    We show that the single, non-photonic electron nuclear modification factor $R_{AA}^e$ is affected by the thermal enhancement of the heavy-baryon to heavy-meson ratio in relativistic heavy-ion collisions with respect to proton-proton collisions. We make use of the dynamical quark recombination model to compute such ratio and show that this produces a sizable suppression factor for $R_{AA}^e$ at intermediate transverse momenta. We argue that such suppression factor needs to be considered, in addition to the energy loss contribution, in calculations of $R_{AA}^e$

  4. Heavy quark threshold dynamics in higher order

    Energy Technology Data Exchange (ETDEWEB)

    Piclum, J.H.

    2007-05-15

    In this work we discuss an important building block for the next-to-next-to-next-to leading order corrections to the pair production of top quarks at threshold. Specifically, we explain the calculation of the third order strong corrections to the matching coefficient of the vector current in non-relativistic Quantum Chromodynamics and provide the result for the fermionic part, containing at least one loop of massless quarks. As a byproduct, we obtain the matching coefficients of the axial-vector, pseudo-scalar and scalar current at the same order. Furthermore, we calculate the three-loop corrections to the quark renormalisation constants in the on-shell scheme in the framework of dimensional regularisation and dimensional reduction. Finally, we compute the third order strong corrections to the chromomagnetic interaction in Heavy Quark Effective Theory. The calculational methods are discussed in detail and results for the master integrals are given. (orig.)

  5. Heavy Quark Coupled Channel Dynamics from Thermal Shifts

    CERN Document Server

    Arriola, Enrique Ruiz; Megias, Eugenio

    2016-01-01

    QCD at finite temperature below the phase transition should be determined in terms of colour singlet states such as hadrons and strings. We show how quark-hadron duality allows extracting sensible information concerning heavy quark and string breaking coupled channel dynamics from Polyakov loop correlators.

  6. Heavy-Quark Diffusion Dynamics in Quark-Gluon Plasma under Strong Magnetic Fields

    CERN Document Server

    Hattori, Koichi; Yee, Ho-Ung; Yin, Yi

    2016-01-01

    We discuss heavy-quark dynamics in the quark-gluon plasma under a strong magnetic field induced by colliding nuclei. By the use of the diagrammatic resummation techniques for Hard Thermal Loop and the external magnetic field, we show analytic results of heavy-quark diffusion coefficient and drag force which become anisotropic due to the preferred spatial orientation in the magnetic field. We argue that the anisotropic diffusion coefficient gives rise to an enhancement/suppression of the heavy-quark elliptic flow depending on the transverse momentum.

  7. Real-time quantum dynamics of heavy quark systems at high temperature

    CERN Document Server

    Akamatsu, Yukinao

    2012-01-01

    On the basis of the closed-time path formalism of non-equilibrium quantum field theory, we derive the real-time quantum dynamics of heavy quark systems. Even though our primary goal is the description of heavy quarkonia, our method allows a unified description of the propagation of single heavy quarks as well as their bound states. To make calculations tractable, we deploy leading-order perturbation theory and consider the non-relativistic limit. Various dynamical equations, such as the master equation for quantum Brownian motion and time-evolution equation for heavy quark and quarkonium forward correlators, are obtained from a single operator, the renormalized effective Hamiltonian. We are thus able to reproduce previous results of perturbative calculations of the drag force and the complex potential simultaneously. In addition, we present stochastic time-evolution equations for heavy quark and quarkonium wave function, which are equivalent to the dynamical equations.

  8. Real-time quantum dynamics of heavy-quark systems at high temperature

    Science.gov (United States)

    Akamatsu, Yukinao

    2013-02-01

    On the basis of the closed-time-path formalism of nonequilibrium quantum field theory, we derive the real-time quantum dynamics of heavy-quark systems. Even though our primary goal is the description of heavy quarkonia, our method allows a unified description of the propagation of single heavy quarks as well as their bound states. To make calculations tractable, we deploy leading-order perturbation theory and consider the nonrelativistic limit. Various dynamical equations, such as the master equation for quantum Brownian motion and the time-evolution equation for heavy-quark and quarkonium forward correlators, are obtained from a single operator: the renormalized effective Hamiltonian. We are thus able to reproduce previous results of perturbative calculations of the drag force and the complex potential simultaneously. In addition, we present stochastic time-evolution equations for the heavy-quark and quarkonium wave function, which are equivalent to the dynamical equations.

  9. Equilibrium distribution of heavy quarks in fokker-planck dynamics

    Science.gov (United States)

    Walton; Rafelski

    2000-01-01

    We obtain an explicit generalization, within Fokker-Planck dynamics, of Einstein's relation between drag, diffusion, and the equilibrium distribution for a spatially homogeneous system, considering both the transverse and longitudinal diffusion for dimension n>1. We provide a complete characterization of the equilibrium distribution in terms of the drag and diffusion transport coefficients. We apply this analysis to charm quark dynamics in a thermal quark-gluon plasma for the case of collisional equilibration.

  10. Can mass-less QCD dynamically generate heavy quarks?

    CERN Document Server

    Cabo-Montes de Oca, Alejandro; Oca, Alejandro Cabo Montes de; Martinez-Pedrera, Danny

    2005-01-01

    As it was suggested by previous works on a modified perturbation expansion for QCD, the possibility for the generation of large quark condensates in the mass-less version of the theory is explored. For this purpose, it is firstly presented a way of well define the Feynman diagrams at any number of loops by just employing dimensional regularization. After that, the calculated zero and one loop corrections to the effective potential indicate a strong instability of the system under the generation of quark condensates. The also evaluated quark condensate dependence of particular two loop terms does not modify the instability picture arising at one loop. The results suggest a possible mechanism for a sort of Top Condensate Model to be a dynamically fixed effective action for mass-less QCD. The inability of lattice calculations in detecting this possibility could be related with the limitations in treating the fermion determinants.

  11. Dynamics of the QCD string with light and heavy quarks

    CERN Document Server

    Gubankova, E C

    1994-01-01

    Abstract: The generalization of the effective action [1] of the quark--antiquark system in the confining vacuum is performed for the case of arbitrary quark masses. The interaction of quarks is described by the averaged Wilson loop for which we use the minimal area law asymptotics. The system is quantized by the path integral method and the quantum Hamiltonian is obtained. It contains not only quark degrees of freedom but also the string energy density. As well as in the equal masses case [1] two dynamical regimes are found [2]: for large orbital excitations (l \\gg 1) the system is represented as rotating string, which leads to asymptotically linear Regge trajectories, while at small l one obtains a potential-like relativistic or nonrelativistic regime. In the limiting cases of light-light and heavy-light mesons a unified description is developed [2]. For the Regge trajectories one obtains nearly straight-line patterns with the slope very close to 1/2 \\pi \\sigma and 1/ \\pi\\sigma correspondingly. The upper bou...

  12. Impact of momentum-space anisotropy on heavy quark dynamics in a QGP medium

    CERN Document Server

    Chandra, Vinod

    2015-01-01

    Momentum space anisotropy present in the quark and gluon distribution functions in the early stages of relativistic heavy ion collisions induces Chromo-Weibel instability in the hot QCD medium created therein. The impact of the Chromo-Weibel instability on the dynamics of a heavy-quark (HQ) traversing in the QGP medium is investigated within the framework of kinetic theory by studying the momentum and temperature behavior of HQ drag and diffusion coefficients. The physics of anisotropy is captured in an effective Vlasov term in the transport equation. The effects of the instability are handled by making a relation with the phenomenologically known jet quenching parameter in RHIC and LHC. Interestingly, the presence of instability significantly affect the temperature and momentum dependences of the HQ drag and diffusion coefficients. These results may have appreciable impact on the experimental observable like the nuclear suppression factor, $R_{AA}(p_T)$, and elliptic flow, $v_2(p_T)$, of heavy mesons in heav...

  13. Impact of momentum space anisotropy on heavy quark dynamics in a QGP medium

    Science.gov (United States)

    Chandra, Vinod; Das, Santosh K.

    2016-05-01

    Momentum space anisotropy present in the quark and gluon distribution functions in relativistic heavy ion collisions induces Chromo-Weibel instability in the hot QCD medium created therein. The impact of the Chromo-Weibel instability on the dynamics of a heavy quark (HQ) traversing in the QGP medium is investigated within the framework of kinetic theory by studying the momentum and temperature behavior of HQ drag and diffusion coefficients. The physics of anisotropy is captured in an effective Vlasov term in the transport equation. The effects of the instability are handled by making a relation with the phenomenologically known jet-quenching parameter in RHIC and LHC. Interestingly, the presence of instability significantly affects the temperature and momentum dependences of the HQ drag and diffusion coefficients. These results may have appreciable impact on the experimental observables such as the nuclear suppression factor, RA A(pT) , and the elliptic flow, v2(pT), of heavy mesons in heavy ion collisions at RHIC and LHC energies which is a matter of future investigation.

  14. Heavy quark dynamics in the QGP: Towards a solution of the RAA and ν2 puzzle

    Directory of Open Access Journals (Sweden)

    Scardina F.

    2016-01-01

    Full Text Available The two key observables related to heavy quarks that have been measured in experiments are the nuclear suppression factor RAA and the elliptic flow ν2. The simultaneous reproduction of these two observables is a puzzle which have challenged all the existing models. We discuss two ingredients responsible for addressing a large part of such a puzzle: the temperature dependence of the energy loss and the full solution of the Boltzmann collision integral for the scattering between the heavy quarks and the particle of the bulk.

  15. Heavy quark masses

    Science.gov (United States)

    Testa, Massimo

    1990-01-01

    In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.

  16. Dynamical collisional energy loss and transport properties of on- and off-shell heavy quarks in vacuum and in the Quark Gluon Plasma

    CERN Document Server

    Berrehrah, Hamza; Aichelin, Jörg; Cassing, Wolfgang; Bratkovskaya, Elena

    2014-01-01

    In this study we evaluate the dynamical collisional energy loss of heavy quarks, their interaction rate as well as the different transport coefficients (drag and diffusion coefficients, $\\hat{q}$, etc). We calculate these different quantities for i) perturbative partons (on-shell particles in the vacuum with fixed and running coupling) and ii) for dynamical quasi-particles (off-shell particles in the QGP medium at finite temperature $T$ with a running coupling in temperature as described by the dynamical quasi-particles model). We use the perturbative elastic $(q(g) Q \\rightarrow q (g) Q)$ cross section for the first case, and the Infrared Enhanced Hard Thermal Loop cross sections for the second. The results obtained in this work demonstrate the effects of a finite parton mass and width on the heavy quark transport properties and provide the basic ingredients for an explicit study of the microscopic dynamics of heavy flavors in the QGP - as formed in relativistic heavy-ion collisions - within transport approa...

  17. Heavy quark production and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Appel, J.A.

    1993-11-01

    This review covers many new experimental results on heavy flavor production and spectroscopy. It also shows some of the increasingly improved theoretical understanding of results in light of basic perturbative QCD and heavy quark symmetry. At the same time, there are some remaining discrepancies among experiments as well as significant missing information on some of the anticipated lowest lying heavy quark states. Most interesting, perhaps, are some clearly measured production effects awaiting full explanation.

  18. Phenomenology of heavy quark systems

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, F.J.

    1987-03-01

    The spectroscopy of heavy quark systems is examined with regards to spin independent and spin dependent potentials. It is shown that a qualitative picture exists of the spin-independent forces, and that a semi-quantitative understanding exists for the spin-dependent effects. A brief review is then given of the subject of the decays of hadrons containing heavy quarks, including weak decays at the quark level, and describing corrections to the spectator model. (LEW)

  19. Heavy quark photoproduction in $pp$ coherent interactions at LHC

    CERN Document Server

    Goncalves, V P; Meneses, A R

    2009-01-01

    In this work we analyse the possibility of constraining the QCD dynamics at high energies studying the heavy quark photoproduction at LHC in coherent interactions. The rapidity distribution and total cross section for charm and bottom production are estimated using three different phenomenological saturation models which successfully describe the HERA data. Our results indicate that the experimental study of the inclusive heavy quark photoproduction can be very useful to discriminate between the classical and quantum versions of the Color Glass Condensate (CGC) formalism.

  20. QCD in heavy quark production and decay

    Energy Technology Data Exchange (ETDEWEB)

    Wiss, J. [Univ. of Illinois, Urbana, IL (United States)

    1997-06-01

    The author discusses how QCD is used to understand the physics of heavy quark production and decay dynamics. His discussion of production dynamics primarily concentrates on charm photoproduction data which are compared to perturbative QCD calculations which incorporate fragmentation effects. He begins his discussion of heavy quark decay by reviewing data on charm and beauty lifetimes. Present data on fully leptonic and semileptonic charm decay are then reviewed. Measurements of the hadronic weak current form factors are compared to the nonperturbative QCD-based predictions of Lattice Gauge Theories. He next discusses polarization phenomena present in charmed baryon decay. Heavy Quark Effective Theory predicts that the daughter baryon will recoil from the charmed parent with nearly 100% left-handed polarization, which is in excellent agreement with present data. He concludes by discussing nonleptonic charm decay which is traditionally analyzed in a factorization framework applicable to two-body and quasi-two-body nonleptonic decays. This discussion emphasizes the important role of final state interactions in influencing both the observed decay width of various two-body final states as well as modifying the interference between interfering resonance channels which contribute to specific multibody decays. 50 refs., 77 figs.

  1. Production asymmetries of $D^{\\pm}$, $\\Lambda_c^{+}/\\Lambda_c^{-}$ and $\\Lambda_b^0/\\overline{\\Lambda}_b^0$ at the LHC from heavy quark recombination mechanism

    CERN Document Server

    Lai, Wai Kin

    2015-01-01

    The asymmetry in the forward region production cross section of $D^{\\pm}$ is calculated using the heavy quark recombination mechanism for $pp$ collisions at $7$~TeV. By suitable choices of four nonperturbative parameters, our calculated results can reproduce those obtained at LHCb. We find $A_p\\sim-1\\%$ when integrated over $2.0\\textrm{ GeV}heavy quark recombination mechanism, we also make predictions on the production asymmetries of $\\Lambda_c^{+}/\\Lambda_c^{-}$ and $\\Lambda_b^0/\\overline{\\Lambda}_b^0$ for $pp$ collisions at $7$~TeV and $14$~TeV in the forward region. We find that the integrated asymmetries for these $\\Lambda$ baryons in the LHCb region are of the order of $\\sim1-3\\%$ and should be measurable.

  2. Heavy quark spectroscopy at LHCb

    CERN Document Server

    INSPIRE-00165164

    2015-01-01

    The analysis of $3.0 fb^{-1}$ of proton-proton collisions collected with the LHCb detector has yielded a broad range of results in spectroscopy of conventional and exotic hadrons with heavy quark(s) inside. We review the LHCb results which have been obtained over the last year.

  3. Heavy-Quark QCD Exotica

    CERN Document Server

    Lebed, Richard F; Swanson, Eric S

    2016-01-01

    This review presents an overview of the remarkable progress in the field of heavy-quark exotic hadrons over the past 15 years. It seeks to be pedagogical rather than exhaustive, summarizing both the progress and specific results of experimental discoveries, and the variety of theoretical approaches designed to explain these new states.

  4. Heavy quark production in pp collisions

    Energy Technology Data Exchange (ETDEWEB)

    McGaughey, P.L. [Los Alamos National Lab., NM (United States); Quack, E. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Ruuskanen, P.V. [Univ. of Helsinki (Finland)]|[Univ. of Jyvaeskylae (Finland)] [and others

    1995-07-01

    A systematic study of the inclusive single heavy quark and heavy-quark pair production cross sections in pp collisions is presented for RHIC and LHC energies. We compare with existing data when possible. The dependence of the rates on the renormalization and factorization scales is discussed. Predictions of the cross sections are given for two different sets of parton distribution functions.

  5. The heavy quark expansion of QCD

    Energy Technology Data Exchange (ETDEWEB)

    Falk, A.F. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy

    1997-06-01

    These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs.

  6. Heavy quark physics from SLD

    Energy Technology Data Exchange (ETDEWEB)

    Messner, R. [Stanford Univ., CA (United States)

    1997-01-01

    This report covers preliminary measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 1993-1995 runs. A measurement of R{sub b} with a lifetime double tag is presented. The high electron beam polarization of the SLC is employed in the direct measurement of the parity-violating parameters A{sub b} and A{sub c} by use of the left-right forward-backward asymmetry. The lifetimes of B{sup +} and B{sup 0} mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p{sub t}) leptons; the second analysis isolates a sample of B meson decays with a two-dimensional impact parameter tag and reconstructs the decay length and charge using a topological vertex reconstruction method.

  7. Heavy-quark QCD vacuum polarisation function. Analytical results at four loops

    Energy Technology Data Exchange (ETDEWEB)

    Kniehl, B.A.; Kotikov, A.V. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2006-07-15

    The first two moments of the heavy-quark vacuum polarisation function at four loops in quantum chromo-dynamics are found in fully analytical form by evaluating the missing massive four-loop tadpole master integrals. (orig.)

  8. Revisiting Uraltsev's BPS limit for Heavy Quarks

    CERN Document Server

    Heinonen, Johannes

    2016-01-01

    Motivated by the recent experimental data of the values of the Heavy Quark Expansion parameters, in particular the spin-orbit and Darwin terms, we argue that nature actually may be close to a limit of QCD which has been suggested by Uraltsev more than ten years ago. Assuming that this limit is not accidental, we derive the relations among the Heavy Quark Expansion parameters that occur up to the order 1/mb^5.

  9. Lowest-lying even-parity anti B{sub s} mesons: heavy-quark spin-flavor symmetry, chiral dynamics, and constituent quark-model bare masses

    Energy Technology Data Exchange (ETDEWEB)

    Albaladejo, M.; Fernandez-Soler, P.; Nieves, J.; Ortega, P.G. [Centro Mixto CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular (IFIC), Institutos de Investigacion de Paterna, Aptd. 22085, Valencia (Spain)

    2017-03-15

    The discovery of the D{sup *}{sub s0}(2317) and D{sub s1}(2460) resonances in the charmed-strange meson spectra revealed that formerly successful constituent quark models lose predictability in the vicinity of two-meson thresholds. The emergence of non-negligible effects due to meson loops requires an explicit evaluation of the interplay between Q anti q and (Q anti q)(q anti q) Fock components. In contrast to the c anti s sector, there is no experimental evidence of J{sup P} = 0{sup +}, 1{sup +} bottom-strange states yet. Motivated by recent lattice studies, in this work the heavy-quark partners of the D{sub s0}{sup *}(2317) and D{sub s1}(2460) states are analyzed within a heavy meson chiral unitary scheme. As a novelty, the coupling between the constituent quark-model P-wave anti B{sub s} scalar and axial mesons and the anti B{sup (*)}K channels is incorporated employing an effective interaction, consistent with heavy-quark spin symmetry, constrained by the lattice energy levels. (orig.)

  10. Using heavy quark fragmentation into heavy hadrons to determine QCD parameters and test heavy quark symmetry

    CERN Document Server

    Randall, Lisa

    1994-01-01

    We present a detailed analysis of the use of heavy quark fragmentation into heavy hadrons for testing the heavy quark effective theory through comparison of the measured fragmentation parameters of the c and b quarks. Our analysis is entirely model independent. We interpret the known perturbative evolution in a way useful for exploiting heavy quark symmetry at low energy. We first show consistency with perturbative QCD scaling for measurements done solely with c quarks. We then apply the perturbative analysis and the heavy quark expansion to relate measurements from ARGUS and LEP. We place bounds on a nonperturbative quark mass suppressed parameter, and compare the values for the b and c quarks. We find consistency with the heavy quark expansion but fairly sizable QCD uncertainties. We also suggest that one might reduce the systematic uncertainty in the result by not extrapolating to low z.

  11. Is Heavy Quark Axion Necessarily Hadronic Axion?

    OpenAIRE

    Chang, Sanghyeon; Kim, Jihn E.

    1993-01-01

    We show that heavy quark axion is not necessarily a hadronic axion, which manifests in the quark and lepton seesaw mechanism. We introduce a heavy $SU(2)$ singlet fermion for each known fermion in order to unify the axion scale and the seesaw scale. The light quarks and leptons gain their masses by the seesaw mechanism. Even though our axion model gives a kind of heavy quark axion, the axion has tree level lepton--axion coupling suppressed by $F_a$, contrary to a widely known belief that heav...

  12. New lattice action for heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Oktay, Mehmet B.; Kronfeld, Andreas S.

    2008-03-01

    We extend the Fermilab method for heavy quarks to include interactions of dimension six and seven in the action. There are, in general, many new interactions, but we carry out the calculations needed to match the lattice action to continuum QCD at the tree level, finding six non-zero couplings. Using the heavy-quark theory of cutoff effects, we estimate how large the remaining discretization errors are. We find that our tree-level matching, augmented with one-loop matching of the dimension-five interactions, can bring these errors below 1%, at currently available lattice spacings.

  13. Recent advances in heavy quark theory

    Energy Technology Data Exchange (ETDEWEB)

    Wise, M. [California Institute of Technology, Pasadena, CA (United States)

    1997-01-01

    Some recent developments in heavy quark theory are reviewed. Particular emphasis is given to inclusive weak decays of hadrons containing a b quark. The isospin violating hadronic decay D{sub s}* {yields} D{sub s}{sup pi}{sup 0} is also discussed.

  14. Heavy Quark Photoproduction in Coherent Interactions at High Energies

    CERN Document Server

    Gonçalves, V P; Meneses, A R

    2009-01-01

    We calculate the inclusive and diffractive photoproduction of heavy quarks in proton-proton collisions at Tevatron and LHC energies, where the photon reaches energies larger than those ones accessible at DESY-HERA. The integrated cross section and the rapidity distributions for charm and bottom production are computed within the color dipole picture employing three phenomenological saturation models based on the Color Glass Condensate formalism. Our results demonstrate that the experimental analyzes of these reactions is feasible and that the cross sections are sensitive to the underlying parton dynamics.

  15. Deep-inelastic production of heavy quarks

    CERN Document Server

    Laenen, Eric; Harris, B W; Matiounine, Y; Migneron, R; Riemersma, S; Smith, J; van Neerven, W L

    1996-01-01

    Deep-inelastic production of heavy quarks at HERA, especially charm, is an excellent signal to measure the gluon distribution in the proton at small $x$ values. By measuring various differential distributions of the heavy quarks this reaction permits additional more incisive QCD analyses due to the many scales present. Furthermore, the relatively small mass of the charm quark, compared to the typical momentum transfer $Q$, allows one to study whether and when to treat this quark as a parton. This reaction therefore sheds light on some of the most fundamental aspects of perturbative QCD. We discuss the above issues and review the feasibility of their experimental investigation in the light of a large integrated luminosity.

  16. Heavy Quarks, QCD, and Effective Field Theory

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Mehen

    2012-10-09

    The research supported by this OJI award is in the area of heavy quark and quarkonium production, especially the application Soft-Collinear E ective Theory (SCET) to the hadronic production of quarkonia. SCET is an e ffective theory which allows one to derive factorization theorems and perform all order resummations for QCD processes. Factorization theorems allow one to separate the various scales entering a QCD process, and in particular, separate perturbative scales from nonperturbative scales. The perturbative physics can then be calculated using QCD perturbation theory. Universal functions with precise fi eld theoretic de nitions describe the nonperturbative physics. In addition, higher order perturbative QCD corrections that are enhanced by large logarithms can be resummed using the renormalization group equations of SCET. The applies SCET to the physics of heavy quarks, heavy quarkonium, and similar particles.

  17. Spin dependence of heavy quark fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Cornet, Fernando [Departamento de Fisica Teorica y del Cosmos and Centro Anadaluz de Fisica de Particulas, Universidad de Granada, E-18071 Granada (Spain)], E-mail: cornet@ugr.es; Garcia Canal, Carlos A. [Departamento de Fisica, Universidad Nacional de La Plata, C.C. 67, La Plata (1900) (Argentina)

    2008-05-01

    We propose that the non-perturbative part of the fragmentation function describing the transition from a heavy quark to a heavy meson is proportional to the square of the produced meson wave function at the origin, taking into account hyperfine interactions. We analyze the effects of this proposal on the number of pseudoscalar mesons compared to the number of vector mesons produced and find a good agreement with experimental data. Finally, we discuss further experimental checks for our hypothesis.

  18. Heavy quarks and CP: Moriond 1985

    Energy Technology Data Exchange (ETDEWEB)

    Bjorken, J.D.

    1985-03-01

    The presentations at the Fifth Moriond Workshop on Heavy Quarks, Flavor Mixing, and CP Violation (La Plagne, France, January 13-19, 1985) are summarized. The following topics are reviewed. What's New (beyond the top, top quarks, bottom quarks, charm quarks, strange quarks, and others); why is all this being done (strong interactions and hadron structure, and electroweak properties); and what next (facilities and can one see CP violation in the B-anti B system). 64 refs., 10 figs.

  19. Electroweak Measurements with Heavy Quarks at SLD

    Energy Technology Data Exchange (ETDEWEB)

    Bellodi, Giulia

    2000-10-03

    The SLD detector collected a sample of 550K hadronic events at the Z{sup 0} peak from e{sup +}e{sup -} collisions at the SLC during the 1993 to 1998 period. Polarized electron beams, a small and stable interaction point and the excellent performance of the 3-D CCD vertex detector provide a unique environment for precision electroweak tests of the Standard Model. Improved measurements of heavy quark electroweak parameters are presented here.

  20. A Heavy Quark Symmetry Approach to Baryons

    Energy Technology Data Exchange (ETDEWEB)

    Albertus, C. [Departamento de Fisica Moderna. Facultad de Ciencias, Universidad de Granada, E-18071 Granada (Spain); Amaro, J.E. [Departamento de Fisica Moderna. Facultad de Ciencias, Universidad de Granada, E-18071 Granada (Spain); Hernandez, E. [Grupo de Fisica Nuclear. Facultad de Ciencias, Universidad de Salamanca, E-37008 Salamanca (Spain); Nieves, J. [Departamento de Fisica Moderna. Facultad de Ciencias, Universidad de Granada, E-18071 Granada (Spain)

    2005-06-13

    We evaluate different properties of baryons with a heavy c or b quark. The use of Heavy Quark Symmetry (HQS) provides with an important simplification of the non relativistic three body problem which can be solved by means of a simple variational approach. This scheme is able to reproduce previous results obtained with more involved Faddeev calculations. The resulting wave functions are parametrized in a simple manner, and can be used to calculate further observables.

  1. Enhanced breaking of heavy quark spin symmetry

    Directory of Open Access Journals (Sweden)

    Feng-Kun Guo

    2014-11-01

    Full Text Available Heavy quark spin symmetry is useful to make predictions on ratios of decay or production rates of systems involving heavy quarks. The breaking of spin symmetry is generally of the order of O(ΛQCD/mQ, with ΛQCD the scale of QCD and mQ the heavy quark mass. In this paper, we will show that a small S- and D-wave mixing in the wave function of the heavy quarkonium could induce a large breaking in the ratios of partial decay widths. As an example, we consider the decays of the ϒ(10860 into the χbJω (J=0,1,2, which were recently measured by the Belle Collaboration. These decays exhibit a huge breaking of the spin symmetry relation were the ϒ(10860 a pure 5S bottomonium state. We propose that this could be a consequence of a mixing of the S-wave and D-wave components in the ϒ(10860. Prediction on the ratio Γ(ϒ(10860→χb0ω/Γ(ϒ(10860→χb2ω is presented assuming that the decay of the D-wave component is dominated by the coupled-channel effects.

  2. Novel Heavy Quark Phenomena in QCD

    CERN Document Server

    Brodsky, Stanley J

    2014-01-01

    Heavy quarks provide a new dimension to QCD, allowing tests of fundamental theory, the nature of color confinement, and the production of new exotic multiquark states. I also discuss novel explanations for several apparently anomalous experimental results, such as the large $t \\bar t$ forward-backward asymmetry observed in $p \\bar p$ colisions at the Tevatron, the large rates for $\\gamma$ or $Z$ plus high-$p_T$ charm jets observed at the Tevatron, the strong nuclear absorption of the $J/\\psi$ observed in $pA$ collisions at the LHC, as well as fixed target experiments at high $x_F$. Precision measurements of the heavy quark distribution in hadrons at high $x$ are needed since intrinsic heavy quarks can play an important role in high $x$ phenomenology as well as predicting a new mechanism for high-$x_F$ Higgs production. The role of multi-parton interactions, such as di-gluon initiated subprocesses for forward quarkonium hadroproduction, is discussed. I also briefly discuss a new approach to the QCD confinement...

  3. Theoretical Aspects of the Heavy Quark Expansion

    CERN Document Server

    Uraltsev, N

    1996-01-01

    I give a brief outline of the theoretical framework for the modern treatment of the strong interaction effects in heavy quark decays, based on first principles of QCD. This model-independent approach is required to meet the precision of current and future experiments. Applications to a few problems of particular practical interest are reviewed, including the precise determination of V_{cb} and V_{ub}. I emphasize the peculiarities of simultaneously accounting for the perturbative and power-suppressed effects necessary for accurate predictions.

  4. Heavy quark colorimetry of QCD matter

    CERN Document Server

    Dokshitzer, Yu L; Dokshitzer, Yu.L.

    2001-01-01

    We consider propagation of heavy quarks in QCD matter. Because of large quark mass, the radiative quark energy loss appears to be qualitatively different from that of light quarks at all energies of practical importance. Finite quark mass effects lead to an in-medium enhancement of the heavy-to-light D/\\pi ratio at moderately large (5--10 GeV) transverse momenta. For hot QCD matter a large enhancement is expected, whose magnitude and shape are exponentially sensitive to the density of colour charges in the medium.

  5. (Super)Yang-Mills at Finite Heavy-Quark Density

    CERN Document Server

    Faedo, Anton F; Mateos, David; Tarrio, Javier

    2014-01-01

    We study the gravitational duals of $d$-dimensional Yang-Mills theories with $d\\leq 6$ in the presence of an ${\\cal O} (N^2)$ density of heavy quarks, with $N$ the number of colors. For concreteness we focus on maximally supersymmetric Yang-Mills, but our results apply to a larger class of theories with or without supersymmetry. The gravitational solutions describe renormalization group flows towards infrared scaling geometries characterized by fixed dynamical and hyperscaling-violating exponents. The special case $d=5$ yields an $AdS_3 \\times \\mathbb{R}^4 \\times S^4$ geometry upon uplifting to M-theory. We discuss the multitude of physical scales that separate different dynamical regimes along the flows, as well as the validity of the supergravity description. We also present exact black brane solutions that encode the low-temperature thermodynamics.

  6. Heavy quark interactions and quarkonium binding

    Science.gov (United States)

    Satz, Helmut

    2009-06-01

    We consider heavy quark interactions in quenched and unquenched lattice QCD. In a region just above the deconfinement point, non-Abelian gluon polarization leads to a strong increase in the binding. Comparing quark-antiquark and quark-quark interaction, the dependence of the binding on the separation distance r is found to be the same for the colorless singlet Q{\\skew3\\bar{Q}} and the colored anti-triplet QQ state. In a potential model description of in-medium J/ψ behavior, this enhancement of the binding leads to a survival up to temperatures of 1.5 Tc or higher; it could also result in J/ψ flow. Based on joint work with O Kaczmarek and F Karsch.

  7. Theory of hadronic production of heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, C.

    1981-07-01

    Conventional theoretical predictions for hadronic production of heavy quarks (Q anti Q) are reviewed and confronted with data. Perturbative hard scattering predictions agree qualitatively well with hidden Q anti Q production (e.g., psi, chi, T) whereas for open Q anti Q-production (e.g., pp ..-->.. ..lambda../sub c//sup +/X) additional mechanisms or inputs are needed to explain the forwardly produced ..lambda../sub c//sup +/ at ISR. It is suggested that the presence of c anti c-pairs on the 1 to 2% level in the hadron Fock state decomposition (intrinsic charm) gives a natural description of the ISR data. The theoretical foundations of the intrinsic charm hypotheses together with its consequences for lepton-induced reactions is discussed in some detail.

  8. Heavy Quark Lifetimes, Mixing and CP Violation

    CERN Document Server

    Blaylock, G

    2000-01-01

    This paper emphasizes four topics that represent some of the year's highlights in heavy quark physics. First of all, a review is given of charm lifetime measurements and how they lead to better understanding of the mechanisms of charm decay. Secondly, the CLEO collaboration's new search for charm mixing is reported, which significantly extends the search for new physics in that sector. Thirdly, important updates in Bs mixing are summarized, which result in a new limit on the mass difference, and which further constrain the unitarity triangle. Finally, the first efforts to measure CP violation in the B system are discussed. Results are shown for the CDF and ALEPH measurements of sin(2beta), as well as the CLEO branching fraction measurements of B-->Kpi,pipi, which have implications for future measurements of alpha.

  9. Heavy Quark Physics on the Lattice

    CERN Document Server

    Bernard, C

    2001-01-01

    I review the current status of lattice calculations of the properties of bound states containing one or more heavy quarks. Many of my remarks focus on the heavy-light leptonic decay constants, such as $f_B$, for which the systematic errors have by now been quite well studied. I also discuss $B$-parameters, semileptonic form factors, and the heavy-light and heavy-heavy spectra. Some of my ``world averages'' are: $f_B=200(30) MeV$, $f_B\\sqrt{\\hat B_{B_d}}= 230(40) MeV$, $f_{B_s}/f_B=1.16(4)$ and $f_{B_s}\\sqrt{\\hat B_{B_s}}/f_B\\sqrt{\\hat B_{B_d}}=1.16(5)$.

  10. Hadronization time of heavy quarks in nuclear matter

    Science.gov (United States)

    Song, Taesoo; Berrehrah, Hamza

    2016-09-01

    We study the hadronization time of heavy quark in nuclear matter by using the coalescence model and the spatial diffusion constant of a heavy quark from lattice quantum chromodynamic calculations, assuming that the main interaction of a heavy quark at the critical temperature is hadronization. It is found that the hadronization time of a heavy quark is about 3 fm /c for 2 π TcDs=6 , if a heavy quark is combined with the nearest light antiquark in coordinate space without any correlation between the momentum of a heavy quark and that of a light antiquark which forms a heavy meson. However, the hadronization time reduces to 0.6 - 1.2 fm /c for charm and 0.4 - 0.9 fm /c for bottom, depending on the heavy meson radius, in the presence of momentum correlation. Considering the interspace between quarks and antiquarks at the critical temperature, it seems that the hadronization of a heavy quark does not happen instantaneously but gradually for a considerable time, if started from the thermal distribution of quarks and antiquarks.

  11. A Review of Heavy-Quark and Chiral Perturbation Theory

    CERN Document Server

    Naboulsi, R

    2003-01-01

    In this paper we discuss the relations between various decays that can be obtained by combining heavy-quark perturbation theory and chiral perturbation theory for the emission of soft pseudoscalar particles. In the heavy-quark limit of QCD the interactions of the heavy quark Q are simplified because of a new set of symmetries not manifestly present in the full QCD. This fact is usually used in the construction of the new effective theory where the heavy-quark mass goes to infinity $(m_Q\\gg \\Lambda_{QCD})$ with its four-velocity fixed. The spin-flavor symmetry group of this new theory with N heavy quarks is SU(2N) because the interactions of the heavy quarks are independent of their spins and flavors. This fact is widely used in the description of the semileptonic decays of $B$ mesons to $D$ and $D^\\ast$ mesons where heavy-quark symmetry allows a parameterization of the decay amplitudes in terms of the single Isgur-Wise function [1].

  12. Soft Gluon Radiation off Heavy Quarks beyond Eikonal Approximation

    Directory of Open Access Journals (Sweden)

    Trambak Bhattacharyya

    2016-01-01

    Full Text Available We calculate the soft gluon radiation spectrum off heavy quarks (HQs interacting with light quarks (LQs beyond small angle scattering (eikonality approximation and thus generalize the dead-cone formula of heavy quarks extensively used in the literatures of Quark-Gluon Plasma (QGP phenomenology to the large scattering angle regime which may be important in the energy loss of energetic heavy quarks in the deconfined Quark-Gluon Plasma medium. In the proper limits, we reproduce all the relevant existing formulae for the gluon radiation distribution off energetic quarks, heavy or light, used in the QGP phenomenology.

  13. Heavy quark production in neutrino-nucleon reactions

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, C.E.M. de; Simoes, J.A.M. (Rio de Janeiro Univ. (Brazil). Inst. de Fisica); Garcia Canal, C.A. (La Plata Univ. Nacional (Argentina))

    1982-05-01

    The heavy quark production (charm and bottom) in neutrino-nucleon reactions is discussed. The greater interest is in the leptonic channels, in particular in the production of two charged leptons in the final state.

  14. Instanton effects on the heavy-quark static potential

    Science.gov (United States)

    Yakhshiev, U. T.; Kim, Hyun-Chul; Turimov, B.; Musakhanov, M. M.; Hiyama, Emiko

    2017-08-01

    We investigate instanton effects on the heavy-quark potential, including its spin-dependent part, based on the instanton liquid model. Starting with the central potential derived from the instanton vacuum, we obtain the spin-dependent part of the heavy-quark potential. We discuss the results of the heavy-quark potential from the instanton vacuum. Finally, we solve the nonrelativistic two-body problem, associated with the heavy-quark potential from the instanton vacuum. The instanton effects on the quarkonia spectra are marginal but are required for quantitative description of the spectra. Supported by Basic Science Research Program through the National Research Foundation (NRF) of Korea funded by the Korean government (Ministry of Education, Science and Technology, MEST), Grant Numbers 2016R1D1A1B03935053 (UY) and 2015R1D1A1A01060707 (HChK) and The work was also partly Supported by RIKEN iTHES Project

  15. Heavy quark symmetry in multi-hadron systems

    CERN Document Server

    Yamaguchi, Y; Hosaka, A; Hyodo, T; Yasui, S

    2014-01-01

    We discuss the properties of hadronic systems containing one heavy quark in the heavy quark limit. The heavy quark symmetry guarantees the mass degeneracy of the states with total spin and parity $(j-1/2)^{P}$ and $(j+1/2)^{P}$ with $j \\geq 1/2$, because the heavy-quark spin is decoupled from the total spin $j$ of the light components called brown muck. We apply this idea to heavy multi-hadron systems, and formulate the general framework to analyze their properties. We demonstrate explicitly the spin degeneracy and the decomposition of the wave functions in exotic heavy hadron systems generated by the one boson exchange potential. The masses of the brown muck can be extracted from theoretical and experimental hadron spectra, leading to the color non-singlet spectroscopy.

  16. Recent results in the NJL model with heavy quarks

    CERN Document Server

    Feldmann, T

    1996-01-01

    We investigate the interplay of chiral and heavy quark symmetries by using the NJL quark model. Heavy quarks with finite masses m(Q) as well as the limit m(Q) to infinity are studied. We found large corrections to the heavy mass scaling law for the pseudoscalar decay constant. The influence of external momenta on the shape parameters of the Isgur-Wise form factor is discussed.

  17. Role of heavy quarks in light hadron fragmentation

    Science.gov (United States)

    Epele, Manuel; García Canal, Carlos; Sassot, R.

    2016-08-01

    We investigate the role of heavy quarks in the production of light flavored hadrons and in the determination of the corresponding nonperturbative hadronization probabilities. We define a general mass variable flavor number scheme for fragmentation functions that accounts for heavy quark mass effects, and perform a global QCD analysis to an up-to-date data set including very precise Belle and BABAR results. We show that the mass dependent picture provides a much more accurate and consistent description of the data.

  18. Searches for Heavy Quark States at ATLAS

    Science.gov (United States)

    (Tom Cheng, Hok-Chuen; ATLAS Collaboration

    2016-11-01

    This talk highlights the latest results of heavy quark searches from the ATLAS collaboration, mainly on resonance searches and vector-like quarks (VLQs) searches. Searches for it resonances using lepton-plus-jets events in proton-proton collisions at center-of-mass energy of 8 and 13 TeV are presented. Limits are set for BSM particles such as topcolor-assisted technicolor Z' TC , Kaluza-Klein (K-K) gluons gKK and K-K excitations of graviton GKK in the Randall-Sundrum model of extra dimensions. VLQs arise naturally in many models such as Little Higgs and Composite Higgs and typically couple preferably to the third generation SM quarks and weak bosons. Limits are set for vector-like bottom (B) and top (T) quarks decay to lepton-plus-jets final states via Hb+X and Ht+X channels in two analyses using 8 and 13 TeV datasets from ATLAS.

  19. Heavy quark jets at the LHC

    CERN Document Server

    Voutilainen, Mikko

    2015-01-01

    We summarize measurements of b and c jet production at the LHC, which are an important signature and background for decays of massive particles such as H-to-b-bbar. These include measurements of the inclusive and dijet production of heavy quark jets, b and c jets produced in association with vector bosons Z and W, and decays of boosted Z bosons into pairs of b-bbar. The current status of b tagging and b jet energy scale is also reviewed. These measurements test perturbative QCD in the four and five-flavor number schemes, and provide insight into the relative importance of heavy flavor production through flavor creation, flavor excitation and gluon splitting channels. The W+c measurement provides additionally a powerful way to probe the strange quark and antiquark sea in the proton. The recent studies looking separately at production of one and two b jets find generally good agreement with theory predictions for two b-jet production, while some discrepancies are observed for singly produced b jets, particularl...

  20. Searches for Heavy Quark States at ATLAS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00357007; The ATLAS collaboration

    2016-01-01

    This talk highlights the latest results of heavy quark searches from the ATLAS collaboration, mainly on resonance searches and vector-like quarks (VLQs) searches. Searches for $t\\bar{t}$ resonances using lepton-plus-jets events in proton-proton collisions at center-of-mass energy at 8 and 13 TeV are presented. Limits are set for BSM particles such as topcolor-assisted technicolor $Z'$ , Kaluza-Klein (K-K) gluons $g_{KK}$ and K-K excitations of graviton $G_{KK}$ in the TC Randall-Sundrum (R-S) model of extra dimensions. VLQs arise naturally in many models such as Little Higgs and Composite Higgs and typically couple preferably to the third generation SM quarks and weak bosons. Limits are set for vector-like bottom (B) and top (T) quarks decay to lepton-plus-jets final states via Hb+X and Ht+X channels in two analyses using 8 and 13 TeV datasets from ATLAS.

  1. Searches for Heavy Quark States at ATLAS

    CERN Document Server

    Cheng, Hok Chuen; The ATLAS collaboration

    2016-01-01

    This talk highlights the latest results of heavy quark searches from the ATLAS collaboration, mainly on resonance searches and vector-like quarks (VLQs) searches. Searches for t\\bar{t} resonances using lepton-plus-jets events in proton-proton collisions at center-of-mass energy at 8 and 13 TeV are presented. Limits are set for BSM particles such as topcolor-assisted technicolor Z'_{TC} , Kaluza-Klein(K-K) gluons g_{KK} and K-K excitations of graviton G_{KK} in the Randall-Sundrum model of extra dimensions. VLQs arise naturally in many models such as Little Higgs and Composite Higgs and typically couple preferably to the third generation SM quarks and weak bosons. Limits are set for vector-like bottom (B) and top (T) quarks decay to lepton-plus-jets final states via Hb+X and Ht+X channels in two analyses using 8 and 13 TeV datasets from ATLAS.

  2. Heavy Quark Thermalization in Classical Lattice Gauge Theory Lessons for Strongly-Coupled QCD

    CERN Document Server

    Laine, Mikko; Philipsen, Owe; Tassler, Marcus

    2009-01-01

    Thermalization of a heavy quark near rest is controlled by the correlator of two electric fields along a temporal Wilson line. We address this correlator within real-time, classical lattice Yang-Mills theory, and elaborate on the analogies that exist with the dynamics of hot QCD. In the weak-coupling limit, it can be shown analytically that the dynamics on the two sides are closely related to each other. For intermediate couplings, we carry out non-perturbative simulations within the classical theory, showing that the leading term in the weak-coupling expansion significantly underestimates the heavy quark thermalization rate. Our analytic and numerical results also yield a general understanding concerning the overall shape of the spectral function corresponding to the electric field correlator, which may be helpful in subsequent efforts to reconstruct it from Euclidean lattice Monte Carlo simulations.

  3. On the Role of One Pion Exchange and Heavy Quark Spin Symmetry in Heavy Meson Molecules

    Directory of Open Access Journals (Sweden)

    Pavón Valderrama M.

    2012-12-01

    Full Text Available In this contribution we consider the theoretical description of heavy mesonantimeson molecules from the effective field theory perspective. We are interested in the role of one pion exchange and heavy quark spin symmetry in the low energy description of the molecular states. We find that pion exchanges are weaker than naively expected. As a consequence, at lowest order in the effective expansion, the heavy meson-antimeson dynamics are driven by contact range interactions that are in turn heavily constrained by heavy quark spin symmetry. We find that if the X(3872 DD¯*${m{Dar D*}}$ is a bound state with quantum numbers JPC = 1++, we should expect the existence of a 2++ DD¯*${m{Dar D*}}$ molecule with a mass of 4012 MeV. If we also assume the X(3915 resonance to be molecular, we end up deriving the location of three new states with masses of 3710, 3820 and 3855 MeV.

  4. Decay constants in the heavy quark limit in models à la Bakamjian and Thomas

    CERN Document Server

    Morénas, V; Oliver, L; Pène, O; Raynal, J C

    1998-01-01

    In quark models à la Bakamjian and Thomas, that yield covariance and Isgur-Wise scaling of form factors in the heavy quark limit, we compute the decay constants $f^{(n)}$ and $f^{(n)}_{1/2}$ of S-wave and P-wave mesons composed of heavy and light quarks. Heavy quark limit scaling $\\sqrt{M} f = Cst$ is obtained, and it is shown that this class of models satisfies the sum rules involving decay constants and Isgur-Wise functions recently formulated by us in the heavy quark limit of QCD. Moreover, the model also satisfies the selection rules of the type $f^{(n)}_{3/2} = 0$ that must hold in this limit. We discuss different Ansätze for the dynamics of the mass operator at rest. For non-relativistic kinetic energies ${p^2 \\over 2m}$ the decay constants are finite even if the potential $V(r)$ has a Coulomb part. For the relativistic form $\\sqrt{p^2 + m^2}$, the S-wave decay constants diverge if there is a Coulomb singularity. Using phenomenological models of the spectrum with relativistic kinetic energy and regula...

  5. Heavy quark production at an Electron-Ion Collider

    CERN Document Server

    Chudakov, E; Hyde, Ch; Furletov, S; Furletova, Yu; Nguyen, D; Stratmann, M; Strikman, M; Weiss, C

    2016-01-01

    An Electron-Ion Collider (EIC) with center-of-mass energies sqrt(s_{eN}) ~ 20-100 GeV and luminosity L ~ 10^{34} cm^{-2} s^{-1} would offer new opportunities to study heavy quark production in high-energy electron or photon scattering on protons and nuclei. We report about an R&D project exploring the feasibility of direct measurements of nuclear gluon densities at large x (gluonic EMC effect, antishadowing) using open charm production at EIC. We describe the charm production rates and angle-momentum distributions at large x and discuss methods of charm reconstruction using next-generation detector capabilities (pi/K identification, vertex reconstruction). The results can be used also for other physics applications of heavy quark production at EIC (fragmentation functions, jets, heavy quark propagation in nuclei).

  6. Helicity probabilities for heavy quark fragmentation into excited mesons

    CERN Document Server

    Yuan, T C

    1995-01-01

    Abstract: In the fragmentation of a heavy quark into a heavy meson whose light degrees of freedom have angular momentum 3/2, all the helicity probabilities are completely determined in the heavy quark limit up to a single probability w_{3/2}. We point out that this probability depends on the longitudinal momentum fraction z of the meson and on its transverse momentum p_\\bot relative to the jet axis. We calculate w_{3/2} as a function of scaling variables corresponding to z and p_\\bot for the heavy quark limit of the perturbative QCD fragmentation functions for b quark to fragment into (b \\bar c) mesons. In this model, the light degrees of freedom prefer to have their angular momentum aligned transverse to, rather than along, the jet axis. Implications for the production of excited heavy mesons, like D^{**} and B^{**}, are discussed.

  7. The physics of heavy quark distributions in hadrons: Collider tests

    Science.gov (United States)

    Brodsky, S. J.; Bednyakov, V. A.; Lykasov, G. I.; Smiesko, J.; Tokar, S.

    2017-03-01

    We present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunction-the "intrinsic" quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ / Z / W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsic heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high xF and novel fixed target measurements which can be tested at the LHC.

  8. On the Renormalization of Heavy Quark Effective Field Theory

    CERN Document Server

    Kilian, W

    1994-01-01

    The construction of heavy quark effective field theory (HqEFT) is extended to arbitrary order in both expansion parameters $\\alpha_s$ and $1/m_q$. Matching conditions are discussed for the general case, and it is verified that this approach correctly reproduces the infrared behaviour of full QCD. Choosing a renormalization scheme in the full theory fixes the renormalization scheme in the effective theory except for the scale of the heavy quark field. Explicit formulae are given for the effective Lagrangian, and one--loop matching renormalization constants are computed for the operators of order $1/m$. Finally, the multiparticle sector of HqEFT is considered.

  9. Nonperturbative Heavy-Quark Interactions in the QGP

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Ralf; Riek, Felix [Texas A and M University, Cyclotron Institute and Physics Department, College Station, TX, 77843-3666 (United States); Hees, Hendrik van [Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany); Greco, Vincenzo [INFN-LNS, Laboratori Nazionali del Sud, and Dipartimento di Fisica e Astronomia, Universita di Catania (Italy); Mannarelli, Massimo [IEEC/CSIC, Universitat Autonoma de Barcelona, Torre C5, E-08193 Bellaterra (Barcelona) (Spain)

    2009-11-01

    We adopt a T-matrix approach to study quarkonium properties and heavy-quark transport in a Quark-Gluon Plasma. The T-matrix approach is well suited to implement potential scattering and thus provides a common framework for low-momentum transfer interactions in heavy-heavy and heavy-light quark systems. We assume that the underlying potentials can be estimated from the heavy-quark free energy computed in lattice QCD. We discuss constraints from vacuum spectroscopy, uncertainties arising from different choices of the potential, and the role of elastic and inelastic widths which are naturally accounted for in the T-matrix formalism.

  10. Heavy Quark and Quarkonium Transport in High Energy Nuclear Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Kai [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Institute for Theoretical Physics, Johann Wolfgang Goethe-University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany); Dai, Wei [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Xu, Nu [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Zhuang, Pengfei [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China)

    2016-12-15

    The strong interaction between heavy quarks and the quark gluon plasma makes the open and hidden charm hadrons be sensitive probes of the deconfinement phase transition in high energy nuclear collisions. Both the cold and hot nuclear matter effects change with the colliding energy and significantly influence the heavy quark and charmonium yield and their transverse momentum distributions. The ratio of averaged quarkonium transverse momentum square and the elliptic flow reveal the nature of the QCD medium created in heavy ion collisions at SPS, RHIC and LHC energies.

  11. Perturbative versus non-perturbative decoupling of heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Knechtli, Francesco [Wuppertal Univ. (Germany). Dept. of Physics; Bruno, Mattia [Brookhaven National Laboratory, Upton, NY (United States); Finkenrath, Jacob [CaSToRC, Cyl Athalassa Campus, Nicosia (Cyprus); Leder, Bjoern [Humboldt Univ. Berlin (Germany). Inst. fuer Physik; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Collaboration: ALPHA Collaboration

    2015-11-15

    We simulate a theory with N{sub f}=2 heavy quarks of mass M. At energies much smaller than M the heavy quarks decouple and the theory can be described by an effective theory which is a pure gauge theory to leading order in 1/M. We present results for the mass dependence of ratios such as t{sub 0}(M)/t{sub 0}(0). We compute these ratios from simulations and compare them to the perturbative prediction. The latter relies on a factorisation formula for the ratios which is valid to leading order in 1/M.

  12. Heavy quark potential from deformed AdS5 models

    Science.gov (United States)

    Zhang, Zi-qiang; Hou, De-fu; Chen, Gang

    2017-04-01

    In this paper, we investigate the heavy quark potential in some holographic QCD models. The calculation relies on a modified renormalization scheme mentioned in a previous work of Albacete et al. After studying the heavy quark potential in Pirner-Galow model and Andreev-Zakharov model, we extend the discussion to a general deformed AdS5 case. It is shown that the obtained potential is negative definite for all quark-antiquark separations, differs from that using the usual renormalization scheme.

  13. Transverse-momentum resummation for heavy-quark hadroproduction

    Directory of Open Access Journals (Sweden)

    Stefano Catani

    2015-01-01

    Full Text Available We consider the production of a pair of heavy quarks (QQ¯ in hadronic collisions. When the transverse momentum qT of the heavy-quark pair is much smaller than its invariant mass, the QCD perturbative expansion is affected by large logarithmic terms that must be resummed to all orders. This behavior is well known from the simpler case of hadroproduction of colorless high-mass systems, such as vector or Higgs boson(s. In the case of QQ¯ production, the final-state heavy quarks carry color charge and are responsible for additional soft radiation (through direct emission and interferences with initial-state radiation that complicates the evaluation of the logarithmically-enhanced terms in the small-qT region. We present the all-order resummation structure of the logarithmic contributions, which includes color flow evolution factors due to soft wide-angle radiation. Resummation is performed at the completely differential level with respect to the kinematical variables of the produced heavy quarks. Soft-parton radiation produces azimuthal correlations that are fully taken into account by the resummation formalism. These azimuthal correlations are entangled with those that are produced by initial-state collinear radiation. We present explicit analytical results up to next-to-leading order and next-to-next-to-leading logarithmic accuracy.

  14. Particle spectra in light and heavy quark jets

    Energy Technology Data Exchange (ETDEWEB)

    Dokshitzer, Yu.L.; Khoze, V.A.; Troyan, S.I. (Lund Univ. (Sweden). Dept. of Theoretical Physics AN SSSR, Leningrad (USSR). Inst. Yadernoj Fiziki)

    1991-10-01

    The application of the analytical perturbative technique to the description of inclusive particle spectra in QCD jets is reviewed. We discuss characteristic properties of the jets generated by heavy quarks and list the prospects for future studies of coherent parton cascades. (author).

  15. Heavy Quarks and Heavy Quarkonia as Tests of Thermalization

    CERN Document Server

    Nagle, J L

    2006-01-01

    We present here a brief summary of new results on heavy quarks and heavy quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma Thermalization" Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.

  16. Interpretation of D(2637) from heavy quark symmetry

    CERN Document Server

    Page, P R

    1999-01-01

    We demonstate from heavy quark symmetry that the width of D(2637) claimed by the DELPHI Collaboration is inconsistent with any bound state with one charm quark predicted in the D(2637) mass region, except possibly D*_3, D_2 or D'.

  17. → + 1 decay in the heavy quark effective theory

    Indian Academy of Sciences (India)

    R Mohanta; A K Giri

    2000-02-01

    Using the heavy quark approximation, we have studied the nonleptonic decay mode → + 1. We have included nonfactorizable contributions as well as factorizable ones in our analysis. The estimated branching ratio for this process is (1.4± 0.1)% and the asymmetry parameter found to be -0.8.

  18. Heavy-quark parton distribution functions and their uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Z. Sullivan and P.M. Nadolsky

    2001-12-07

    We investigate the uncertainties of the heavy-quark parton distribution functions in the variable avor number scheme. Because the charm- and bottom-quark parton distribution functions (PDFs) are constructed predominantly from the gluon PDF, it is a common practice to assume that the heavy-quark and gluon uncertainties are the same. We show that this approximation is a reasonable first guess, but it is better for bottom quarks than charm quarks. We calculate the PDF uncertainty for t-channel single-top-quark production using the Hessian matrix method, and predict a cross section of 2.12{sub -0.29}{sup +0.32} pb at run II of the Tevatron.

  19. Finite density QCD phase transition in the heavy quark region

    CERN Document Server

    Saito, H; Kanaya, K; Ohno, H; Ejiri, S; Nakagawa, Y; Hatsuda, T; Umeda, T

    2012-01-01

    We extend our previous study of the QCD phase structure in the heavy quark region to non-zero chemical potentials. To identify the critical point where the first order deconfining transition terminates, we study an effective potential defined by the probability distribution function of the plaquette and the Polyakov loop. The reweighting technique is shown to be powerful in evaluating the effective potential in a wide range of the plaquette and Polyakov loop expectation values. We adopt the cumulant expansion to overcome the sign problem in the calculation of complex phase of the quark determinant. We find that the method provides us with an intuitive and powerful way to study the phase structure. We estimate the location of the critical point at finite chemical potential in the heavy quark region.

  20. Anatomy of double heavy-quark initiated processes

    CERN Document Server

    Lim, Matthew; Ridolfi, Giovanni; Ubiali, Maria

    2016-01-01

    A number of phenomenologically relevant processes at hadron colliders, such as Higgs and Z boson production in association with b quarks, can be conveniently described as scattering of heavy quarks in the initial state. We present a detailed analysis of this class of processes, identifying the form of the leading initial-state collinear logarithms that allow the relation of calculations performed in different flavour schemes in a simple and reliable way. This procedure makes it possible to assess the size of the logarithmically enhanced terms and the effects of their resummation via heavy-quark parton distribution functions. As an application, we compare the production of (SM-like and heavy) scalar and vector bosons in association with b quarks at the LHC in the four- and five-flavour schemes as well as the production of a heavy Z' in association with top quarks at a future 100 TeV hadron collider in the five- and six-flavour schemes. We find that, in agreement with a previous analysis of single heavy-quark i...

  1. Anatomy of double heavy-quark initiated processes

    Science.gov (United States)

    Lim, Matthew; Maltoni, Fabio; Ridolfi, Giovanni; Ubiali, Maria

    2016-09-01

    A number of phenomenologically relevant processes at hadron colliders, such as Higgs and Z boson production in association with b quarks, can be conveniently described as scattering of heavy quarks in the initial state. We present a detailed analysis of this class of processes, identifying the form of the leading initial-state collinear logarithms that allow the relation of calculations performed in different flavour schemes in a simple and reliable way. This procedure makes it possible to assess the size of the logarithmically enhanced terms and the effects of their resummation via heavy-quark parton distribution functions. As an application, we compare the production of (SM-like and heavy) scalar and vector bosons in association with b quarks at the LHC in the four- and five-flavour schemes as well as the production of a heavy Z ' in association with top quarks at a future 100 TeV hadron collider in the five- and six-flavour schemes. We find that, in agreement with a previous analysis of single heavy-quark initiated processes, the size of the initial-state logarithms is mitigated by a kinematical suppression. The most important effects of the resummation are a shift of the central predictions typically of about 20% at a justified value of the scale of each considered process and a significant reduction of scale variation uncertainties.

  2. Tomography of the QGP by heavy quarks

    Science.gov (United States)

    Song, T.; Berrehrah, H.; Bratkovskaya, E. L.; Cabrera, D.; Cassing, W.; Torres-Rincon, J. M.; Tolos, L.

    2016-08-01

    The dynamics of partons and hadrons in ultra-relativistic nucleus-nucleus collisions is analyzed within the Parton-Hadron-String Dynamics (PHSD) transport approach, which is based on a dynamical quasiparticle model for the partonic phase (DQPM) including a dynamical hadronization scheme while reproducing lattice QCD results in thermodynamic equilibrium for the equation-of-state as well as transport coefficients like shear and bulk viscosities, the electric conductivity or the charm diffusion coefficient of the hot QCD medium. In this contribution we report on the recent results on the charm dynamics and elliptic flow in Au+Au collisions at RHIC and Pb+Pb reactions at the LHC as well as on the single electron spectra from D— and B—meson semileptonic decays in Au+Au collisions at √sNN =200 and 62.4 GeV. We find that the PHSD approach well describes the Raa and elliptic flow v2 of open charm mesons in Au+Au collisions at √sNN = 200 GeV (from STAR) and 2.76 TeV (from ALICE) as well as the elliptic flow of single electrons at √sNN = 200 and 62.4 GeV (from PHENIX), however, the large Raa at √sNN = 62.4 GeV is not reproduced at all which might indicate a new ’PHENIX puzzle’.

  3. Two-loop anomalous dimensions for currents of baryons with two heavy quarks in NRQCD

    CERN Document Server

    Kiselev, V V

    1998-01-01

    We present analytical results on the two-loop anomalous dimensions of currents for baryons, containing two heavy quarks $J = [Q^{iT}C\\Gamma\\tau Q^j]\\Gamma' q^k\\epsilon_{ijk}$ with arbitrary Dirac matrices $\\Gamma$ and velocity of heavy quarks and the inverse heavy quark mass. It is shown, that in this approximation the anomalous dimensions do not depend on the Dirac structure of the current under consideration.

  4. Molecular partners of the X(3872) from heavy-quark spin symmetry: a fresh look

    Science.gov (United States)

    Baru, V.; Epelbaum, E.; Filin, A. A.; Hanhart, C.; Nefediev, A. V.

    2017-03-01

    The heavy-quark spin symmetry (HQSS) partners of the X(3872) molecule are investigated in a chiral effective field theory (EFT) approach which incorporates contact and one-pion exchange interactions. The integral equations of the Lippmann-Schwinger type are formulated and solved for the coupled-channel problem for the DD¯, DD¯*, and D*D¯* systems with the quantum numbers JPC = 1++, 1+-, 0++, and 2++. We confirm that, if the X(3872) is a 1++DD¯* molecular state then, in the strict heavy-quark limit, there exist three partner states, with the quantum numbers 1+-, 0++, and 2++, which are degenerate in mass. At first glance, this result looks natural only for the purely contact pionless theory since pions contribute differently to different transition potentials and, therefore, may lift the above degeneracy. Nevertheless, it is shown that, by an appropriate unitary transformation, the Lippmann-Schwinger equation in each channel still can be brought to a block-diagonal form, with the same blocks for all quantum numbers, so that the degeneracy of the bound states in different channels is preserved. We stress that neglecting some of the coupled-channel transitions in an inconsistent manner leads to a severe violation of HQSS and yields regulator-dependent results for the partner states. The effect of HQSS violation in combination with nonperturbative pion dynamics on the pole positions of the partner states is discussed.

  5. Molecular partners of the X(3872 from heavy-quark spin symmetry: a fresh look

    Directory of Open Access Journals (Sweden)

    Baru V.

    2017-01-01

    Full Text Available The heavy-quark spin symmetry (HQSS partners of the X(3872 molecule are investigated in a chiral effective field theory (EFT approach which incorporates contact and one-pion exchange interactions. The integral equations of the Lippmann-Schwinger type are formulated and solved for the coupled-channel problem for the DD̄, DD̄*, and D*D̄* systems with the quantum numbers JPC = 1++, 1+−, 0++, and 2++. We confirm that, if the X(3872 is a 1++DD̄* molecular state then, in the strict heavy-quark limit, there exist three partner states, with the quantum numbers 1+−, 0++, and 2++, which are degenerate in mass. At first glance, this result looks natural only for the purely contact pionless theory since pions contribute differently to different transition potentials and, therefore, may lift the above degeneracy. Nevertheless, it is shown that, by an appropriate unitary transformation, the Lippmann-Schwinger equation in each channel still can be brought to a block-diagonal form, with the same blocks for all quantum numbers, so that the degeneracy of the bound states in different channels is preserved. We stress that neglecting some of the coupled-channel transitions in an inconsistent manner leads to a severe violation of HQSS and yields regulator-dependent results for the partner states. The effect of HQSS violation in combination with nonperturbative pion dynamics on the pole positions of the partner states is discussed.

  6. Parameters of heavy quark effective theory from N{sub f}=2 lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Blossier, Benoit [CNRS, Orsay (France). LPT; Paris-11 Univ., 91 - Orsay (France); Della Morte, Michele [Mainz Univ. (Germany). Inst. fuer Kernphysik; Fritzsch, Patrick [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Garron, Nicolas [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Simma, Hubert; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Tantalo, Nazario [Rome-3 Univ. (Italy). Dipt. di Fisica; INFN, Sezione di Roma (Italy)

    2012-07-15

    We report on a non-perturbative determination of the parameters of the lattice Heavy Quark Effective Theory (HQET) Lagrangian and of the time component of the heavy-light axial-vector current with N{sub f} = 2 flavors of massless dynamical quarks. The effective theory is considered at the 1/m{sub h} order, and the heavy mass m{sub h} covers a range from slightly above the charm to beyond the beauty region. These HQET parameters are needed to compute, for example, the b-quark mass, the heavy-light spectrum and decay constants in the static approximation and to order 1/m{sub h} in HQET. The determination of the parameters is done non-perturbatively. The computation reported in this paper uses the plaquette gauge action and two different static actions for the heavy quark described by HQET. For the light-quark action we choose non-perturbatively O(a)-improved Wilson fermions.

  7. Transport coefficients of heavy quarks around $T_c$ at finite quark chemical potential

    CERN Document Server

    Berrehrah, H; Aichelin, J; Cassing, W; Torres-Rincon, J M; Bratkovskaya, E

    2014-01-01

    The interactions of heavy quarks with the partonic environment at finite temperature $T$ and finite quark chemical potential $\\mu_q$ are investigated in terms of transport coefficients within the Dynamical Quasi-Particle model (DQPM) designed to reproduce the lattice-QCD results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature $T_c$. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around $T_c$, at $\\mu_q=0$ as well as at finite $\\mu_q$. Close and above $T_c$ its absolute value matches the lQCD calculations for $\\mu_q=0$. The smooth transition of the heavy quark transport coefficients from the hadronic to the partonic medium corresponds to a cross over in line with lattice calculations, and differs substantially from perturbative QCD (pQCD) calculations which show a large discontinuity at $T_c$. This indicates that in the vicini...

  8. Franck-Condon principle for heavy-quark hadron decays

    CERN Document Server

    Llanes-Estrada, Felipe J; General, Ignacio G; Wang, Ping

    2008-01-01

    The Franck-Condon principle governing molecular electronic transitions is utilized to study heavy-quark hadron decays. This provides a direct assessment of the wavefunction of the parent hadron if the momentum distribution of the open-flavor decay products is measured. Model-independent results include an experimental distinction between quarkonium and exotica (hybrids, tetraquarks...), an off-plane correlator signature for tetraquarks and a direct probe of the sea quark orbital wavefunction relevant in the discussion of 3S_1 or 3P_0 decay mechanisms.

  9. Measurements of heavy quark production via single leptons at PHENIX

    CERN Document Server

    Hornback, Donald

    2008-01-01

    The measurement of single leptons from the semi-leptonic decay of heavy-flavor hadrons has long been a means for studying heavy-quark production. PHENIX has measured single muons in pp collisions at forward rapidity and single electrons in both pp and AuAu collisions at mid-rapidity at sqrt(s_NN)=200 GeV. The most recent PHENIX single lepton results are presented in the context of state-of-the-art pQCD calculations. An updated azimuthal anisotropy, v2(pT), measurement for heavy-flavor single electrons in AuAu collisions is also presented.

  10. Magnetic Moments of Baryons with a Heavy Quark

    CERN Document Server

    Weigel, H

    2003-01-01

    We compute magnetic moments of baryons with a heavy quark in the bound state approach for heavy baryons. In this approach the heavy baryon is considered as a heavy meson bound to a light baryon. The latter is represented as a soliton excitation of light meson fields. We obtain the magnetic moments by sandwiching pertinent components of the electromagnetic current operator between the bound state wave--functions. We extract this current operator from the coupling to the photon field after extending the action to be gauge invariant.

  11. X(3872 and its charmonium content in Heavy Quark limit

    Directory of Open Access Journals (Sweden)

    Cincioglu Elif

    2016-01-01

    Full Text Available X(3872 still presents many puzzles more than a decade after its discovery. Some of its properties, like the isospin violating decays, can easily be accommodated in a molecular model, whereas its other properties, such as radiative decays can be more naturally explained in the quarkonium picture. The best of these schemes can be combined in a picture of X(3872 where it is dominantly a molecular state with some charmonium components. In this work, we present a model based on heavy quark symmetry which describes X(3872 as a superposition of molecular and charmonium components.

  12. Heavy Quark diffusion from lattice QCD spectral functions

    CERN Document Server

    Ding, H -T; Kaczmarek, O; Karsch, F; Satz, H; Soeldner, W

    2011-01-01

    We analyze the low frequency part of charmonium spectral functions on large lattices close to the continuum limit in the temperature region $1.5\\lesssim T/T_c\\lesssim 3$ as well as for $T \\simeq 0.75T_c$. We present evidence for the existence of a transport peak above $T_c$ and its absence below $T_c$. The heavy quark diffusion constant is then estimated using the Kubo formula. As part of the calculation we also determine the temperature dependence of the signature for the charmonium bound state in the spectral function and discuss the fate of charmonium states in the hot medium.

  13. Heavy Quarks, Origin of Mass, and CP Violation for Universe

    CERN Document Server

    Hou, George W S

    2013-01-01

    A scale-invariant "Gap Equation" is constructed for chiral quark $Q$ by Goldstone, or $V_L$, exchange, where massless input is guaranteed by gauge invariance. A numerical solution is found for Yukawa coupling $\\sim 4\\pi$. In turn, because this gap equation is scale invariant, the strong coupling solution is compatible with a 126 GeV dilaton, which would be a true messenger from higher energies. Some possible phenomena pertaining to heavy chiral quarks at few TeV scale is offered. Adding this heavy quark sector may provide enough CP violation for generating the matter dominance of the Universe.

  14. Energy loss for heavy quarks in relation to light partons: is radiative energy loss for heavy quarks anomalous?

    Science.gov (United States)

    Lacey, Roy A; Wei, R; Ajitanand, N N; Alexander, J M; Gong, X; Jia, J; Mawi, A; Mohapatra, S; Reynolds, D; Salnikov, S; Taranenko, A

    2009-10-01

    The scaling properties of jet-suppression measurements are compared for nonphotonic electrons (e+/-) and neutral pions (pi(0)) in Au+Au collisions at sqrt[S(NN)]=200 GeV. For a broad range of transverse momenta and collision centralities, the comparison is consistent with jet quenching dominated by radiative energy loss for both heavy and light partons. Less quenching is indicated for heavy quarks via e+/-; this gives an independent estimate of the transport coefficient q that agrees with its magnitude obtained from quenching of light partons via pi(0)'s.

  15. Heavy-quark expansion for D and B mesons in nuclear matter

    CERN Document Server

    Buchheim, Thomas; Kampfer, Burkhard

    2014-01-01

    The planned experiments at FAIR enable the study of medium modifications of $D$ and $B$ mesons in (dense) nuclear matter. Evaluating QCD sum rules as a theoretical prerequisite for such investigations encounters heavy-light four-quark condensates. We utilize an extended heavy-quark expansion to cope with the condensation of heavy quarks.

  16. Heavy-quark expansion for D and B mesons in nuclear matter

    Directory of Open Access Journals (Sweden)

    Buchheim Thomas

    2014-01-01

    Full Text Available The planned experiments at FAIR enable the study of medium modifications of D and B mesons in (dense nuclear matter. Evaluating QCD sum rules as a theoretical prerequisite for such investigations encounters heavy-light four-quark condensates. We utilize an extended heavy-quark expansion to cope with the condensation of heavy quarks.

  17. Heavy Quarks Production in Hadronic Processes: Qualitative Study of Higher-Order Fock States

    Institute of Scientific and Technical Information of China (English)

    N. Mebarki; K. Benhizia; Z. Belghobsi; D. Bouaziz

    2009-01-01

    The contribution of the two particles Fock states for the production of a heavy quark in proton-pion and photon-pion collisions is studied. It is shown that the effect depends strongly on the produced heavy quark mass, and the choice of the factorization scale.

  18. Energy change of a heavy quark in a viscous quark–gluon plasma with fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Bing-feng, E-mail: jiangbf@mails.ccnu.edu.cn [Center for Theoretical Physics and School of Sciences, Hubei University for Nationalities, Enshi, Hubei 445000 (China); Hou, De-fu, E-mail: houdf@mail.ccnu.edu.cn [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan, Hubei 430079 (China); Li, Jia-rong, E-mail: ljr@mail.ccnu.edu.cn [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan, Hubei 430079 (China)

    2016-09-15

    When a heavy quark travels through the quark–gluon plasma, the polarization and fluctuating chromoelectric fields will be produced simultaneously in the plasma. The drag force due to those fields exerting in return on the moving heavy quark will cause energy change to it. Based on the dielectric functions derived from the viscous chromohydrodynamics, we have studied the collisional energy change of a heavy quark traversing the viscous quark–gluon plasma including fluctuations of chromoelectric field. Numerical results indicate that the chromoelectric field fluctuations lead to an energy gain of the moving heavy quark. Shear viscosity suppresses the fluctuation-induced energy gain and the viscous suppression effect for the charm quark is much more remarkable than that for the bottom quark. While, the fluctuation energy gain is much smaller than the polarization energy loss in magnitude and the net energy change for the heavy quark is at loss.

  19. Measurement of Heavy Quark cross-sections at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Annovi, Alberto; /Frascati

    2007-09-01

    Abstract: The measurement of heavy quark cross-sections provides important tests of the QCD theory. This paper reviews recent measurements of single b-quark and correlated b-quark cross-sections at CDF. Two new measurements of the single b-quark production at CDF agree with the first result from CDF Run II. This clarifies the experimental situation and confirms the recent agreement of theoretical prediction with data. A new measurement of the correlated b{bar b} cross-section with dimuon events at CDF is presented. It agrees with theory and it does not confirm the anomalously large b{bar b} cross-section seen in Run I by CDF and D0 in dimuon events.

  20. Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation

    CERN Document Server

    Ali, A; Polosa, A D; Riquer, V

    2014-01-01

    Assuming the dominance of the spin-spin interaction in a diquark, we point out that the mass differences in the beauty sector M(Z_b') - M(Z_b) scale with quark masses as expected in QCD, with respect to the corresponding mass difference M(Z_c') - M(Z_c). Notably, we show that the decays Upsilon(10890) --> (h_b(1P), h_b(2P)) pi pi are compatible with heavy-quark spin conservation once the contributions of Z_b,Z_b' intermediate states are taken into account, Upsilon(10890) being either a Upsilon(5S) or the beauty analog of Y_c(4260).

  1. Probing nuclear gluons with heavy quarks at EIC

    CERN Document Server

    Chudakov, E; Hyde, Ch; Furletov, S; Furletova, Yu; Nguyen, D; Stratmann, M; Strikman, M; Weiss, C; Yoshida, R

    2016-01-01

    We explore the feasibility of direct measurements of nuclear gluon densities using heavy-quark production (open charm, beauty) at a future Electron-Ion Collider (EIC). We focus on the regions x > 0.3 (EMC effect) and x ~ 0.05-0.1 (antishadowing), where the nuclear modifications of the gluon density offer insight into non-nucleonic degrees of freedom and the QCD structure of nucleon-nucleon interactions. We describe the charm production rates and momentum distributions in nuclear deep-inelastic scattering (DIS) at large x_B, and comment on the possible methods for charm reconstruction using next-generation detectors at the EIC (pi/K identification, tracking, vertex detection).

  2. Disentangling the timescales behind the nonperturbative heavy quark potential

    Science.gov (United States)

    Burnier, Yannis; Rothkopf, Alexander

    2012-09-01

    The static part of the heavy quark potential has been shown to be closely related to the spectrum of the rectangular Wilson loop. In particular the lowest lying positive frequency peak encodes the late time evolution of the two-body system, characterized by a complex potential. While initial studies assumed a perfect separation of early- and late-time physics, where a simple Lorentzian (Breit-Wigner) shape suffices to describe the spectral peak, we argue that scale decoupling in general is not complete. Thus early-time, i.e., nonpotential effects significantly modify the shape of the lowest peak. We derive on general grounds an improved peak distribution that reflects this fact. Application of the improved fit to nonperturbative lattice QCD spectra now yields a potential that is compatible with a transition to a deconfined screening plasma.

  3. Gluon number fluctuations with heavy quarks at HERA

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiang-Rong; ZHOU Dai-Cui

    2011-01-01

    We study the effect of gluon number fluctuations (Pomeron loops) on the proton structure function at HERA.It is shown that the description of charm and bottom quarks and longitudinal structure functions are improved,with x2/d.o.f=0.803 (fluctuations) as compared with x2/d.o.f=0.908 (without fluctuations),once the gluon number fluctuations are included.We find that in the gluon number fluctuation case the heavy quarks do not play an important role in the proton structure function as the saturation model.The successful description of the HERA data indicates that the gluon number fluctuation could be one of the key mechanisms to describe the proton structure function at HERA energies.

  4. ``Heavy-water Lattice and Heavy-Quark''

    Science.gov (United States)

    Maksoed, Ssi, Wh-

    Refer to Birgitt Roettger-Roessler: ``Feelings at the Margins'', 2014 retrieved the Vienna, 2006 UNIDO Research Programme: Combating Marginalization and Poverty through Industrial Development/COMPID. Also from Vienna, on Feb 18-22, 1963 reported Technical Report Series 20 about ``Heavy Water Lattice''. Failed to relates scale-invariant properties of public-Debt growth to convergence in perturbation theory, sought JH Field: ``Convergence & Gauge Dependence Properties:..''. Furthers, in GP Lepage: ``On the Viabilities of Lattice Perturbation Theory'', 1992 stated: ``in terms of physical quantities, like the heavy-quark potential, greatly enhanced the predictive power of lattice perturbation theory''. Acknowledgements to HE. Mr. H. TUK SETYOHADI, Jl. Sriwijaya Raya 3, South-Jakarta, INDONESIA.

  5. Resummation of large logarithms in the heavy quark effects on the parton distributions inside the virtual photon

    CERN Document Server

    Kitadono, Yoshio; Uematsu, Tsuneo; Ueda, Takahiro

    2010-01-01

    We discuss the resummation of the large logarithmic terms appearing in the heavy quark effects on parton distribution functions inside the virtual photon. We incorporate heavy quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy quark mass effects on the parton distributions in the virtual photon. We numerically calculate parton distributions using the formulae derived in this work, and discuss the property of the resummed heavy quark effects.

  6. Lattice heavy quark effective theory and the isgur-wise function

    CERN Document Server

    Hashimoto, S

    1996-01-01

    We compute the Isgur-Wise function using heavy quark effective theory formulated on the lattice. The non-relativistic kinetic energy term of the heavy quark is included to the action as well as terms remaining in the infinite quark mass limit. The classical velocity of the heavy quark is renormalized on the lattice and we determine the renormalized velocity non-perturbatively using the energy-momentum dispersion relation. The slope parameter of the Isgur-Wise function at zero recoil is obtained at \\beta=6.0 on a 24^3\\times 48 lattice for three values of m_{Q}.

  7. Perturbative heavy quark fragmentation function through O(α2s)

    Science.gov (United States)

    Melnikov, Kirill; Mitov, Alexander

    2004-08-01

    We derive the initial condition for the perturbative fragmentation function of a heavy quark through order O(α2s) in the MS¯ scheme. This initial condition is useful for computing heavy quark (or lepton, in case of QED) energy distributions from calculations with massless partons. In addition, the initial condition at O(α2s) can be used to resum collinear logarithms ln(Q2/m2) in heavy quark energy spectrum with next-to-next-to-leading logarithmic accuracy by solving the DGLAP equation.

  8. Resummed jet rates with heavy quarks in electron-positron collisions

    OpenAIRE

    Rodrigo, German; Krauss, Frank

    2003-01-01

    Expressions for Sudakov form factors for heavy quarks are presented. They are used to construct resummed jet rates in electron-positron annihilation. Predictions are given for production of bottom quarks at LEP and top quarks at the Linear Collider.

  9. Heavy quarks and nuclei, or the charm & beauty of nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Kharzeev, D.

    1997-09-22

    This report contains viewgraphs on the following: why heavy quarks? Heavy quarkonium in QCD vacuum and in matter; Phenomenology of quarkonium production; Induced decay of QCD vacuum in heavy ion collisions? Implications for quarkonium production; and Outlook.

  10. Helicity probabilities for heavy quark fragmentation into heavy-light excited mesons

    CERN Document Server

    Yuan, T C

    1995-01-01

    After a brief review on how heavy quark symmetry constraints the helicity fragmentation probabilities for a heavy quark hadronizes into heavy-light hadrons, we present a heavy quark fragmentation model to extract the value for the Falk-Peskin probability w_{3/2} describing the fragmentation of a heavy quark into a heavy-light meson whose light degrees of freedom have angular momentum {3 \\over 2}. We point out that this probability depends on the longitudinal momentum fraction z of the meson and on its transverse momentum p_\\bot relative to the jet axis. In this model, the light degrees of freedom prefer to have their angular momentum aligned transverse to, rather than along, the jet axis. Implications for the production of excited heavy mesons, like D^{**} and B^{**}, are briefly discussed.

  11. Histograms in heavy-quark QCD at finite temperature and density

    CERN Document Server

    Saito, H; Aoki, S; Kanaya, K; Nakagawa, Y; Ohno, H; Okuno, K; Umeda, T

    2013-01-01

    We study the phase structure of lattice QCD with heavy quarks at finite temperature and density by a histogram method. We determine the location of the critical point at which the first-order deconfining transition in the heavy-quark limit turns into a crossover at intermediate quark masses through a change of the shape of the histogram under variation of coupling parameters. We estimate the effect of the complex phase factor which causes the sign problem at finite density, and show that, in heavy-quark QCD, the effect is small around the critical point. We determine the critical surface in 2+1 flavor QCD in the heavy-quark region at all values of the chemical potential mu including mu=infty.

  12. Heavy quark potential and jet quenching parameter in a D-instanton background

    CERN Document Server

    Zhang, Zi-qiang; Chen, Gang

    2016-01-01

    Applying the AdS/CFT correspondence, two important quantities, heavy quark potential and jet quenching parameter, are calculated in a D-instanton background. This dual gravitational theory is related to a near horizon limit of stack of black D3-branes with homogeneously distributed D-instantons. It is shown that the presence of instantons affects heavy quark potential and jet quenching parameter.

  13. Hidden-beauty charged tetraquarks and heavy quark spin conservation

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Maiani, L.; Polosa, A.D.; Riquer, V. [Rome-3 Univ. (Italy). Dipt. di Fisica; INFN, Sezione di Roma (Italy)

    2014-12-15

    Assuming the dominance of the spin-spin interaction in a diquark, we point out that the mass differences in the beauty sector M(Z'{sub b}){sup ±}-M(Z{sub b}){sup ±} scale with quark masses as expected in QCD, with respect to the corresponding mass difference M(Z'{sub c}){sup ±}-M(Z{sub c}){sup ±}. Notably, we show that the decays Υ(10890)→(h{sub b}(1P),h{sub b}(2P))π{sup +}π{sup -} are compatible with heavy-quark spin conservation once the contributions of Z{sub b},Z'{sub b} intermediate states are taken into account, Υ(10890) being either a Υ(5S) or the beauty analog of Y{sub c}(4260). We also consider the role of Z{sub b},Z'{sub b} in Υ(10890)→Υ(nS)ππ decays and of light quark spin non-conservation in Z{sub b}, Z'{sub b} decays into BB{sup *} and B{sup *}B{sup *}. Indications on possible signatures of the still missing X{sub b} resonance are proposed.

  14. Hidden-beauty charged tetraquarks and heavy quark spin conservation

    Science.gov (United States)

    Ali, A.; Maiani, L.; Polosa, A. D.; Riquer, V.

    2015-01-01

    Assuming the dominance of the spin-spin interaction in a diquark, we point out that the mass difference in the beauty sector M (Zb')±-M (Zb)± scales with quark masses as expected in QCD, with respect to the corresponding mass difference M (Zc')±-M (Zc)± . Notably, we show that the decays ϒ (10890 )→ϒ (n S )π+π- and ϒ (10890 )→(hb(1 P ),hb(2 P ))π+π- are compatible with heavy quark spin conservation if the contributions of Zb,Zb' intermediate states are taken into account, ϒ (10890 ) being either a ϒ (5 S ) or the beauty analog of Yc(4260 ). Belle results on these decays support the quark spin wave function of the Z states as tetraquarks. We also consider the role of light quark spin nonconservaton in Zb,Zb' decays into B B* and B*B*. Indications of possible signatures of the still missing Xb resonance are proposed.

  15. Effective Field Theory approach to heavy quark fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Fickinger, Michael [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,Staudingerweg 9, 55099 Mainz (Germany); Fleming, Sean [Department of Physics, University of Arizona,1118 E. Fourth Street, Tucson, AZ 85721 (United States); Kim, Chul [Institute of Convergence Fundamental Studies and School of Liberal Arts,Seoul National University of Science and Technology,232 Gongneung-ro, Nowon-gu, Seoul 01811 (Korea, Republic of); Mereghetti, Emanuele [Theoretical Division, Los Alamos National Laboratory Los Alamos,Los Alamos, NM 87545 (United States)

    2016-11-17

    Using an approach based on Soft Collinear Effective Theory (SCET) and Heavy Quark Effective Theory (HQET) we determine the b-quark fragmentation function from electron-positron annihilation data at the Z-boson peak at next-to-next-to leading order with next-to-next-to leading log resummation of DGLAP logarithms, and next-to-next-to-next-to leading log resummation of endpoint logarithms. This analysis improves, by one order, the previous extraction of the b-quark fragmentation function. We find that while the addition of the next order in the calculation does not much shift the extracted form of the fragmentation function, it does reduce theoretical errors indicating that the expansion is converging. Using an approach based on effective field theory allows us to systematically control theoretical errors. While the fits of theory to data are generally good, the fits seem to be hinting that higher order correction from HQET may be needed to explain the b-quark fragmentation function at smaller values of momentum fraction.

  16. Heavy-quark production in deep-inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, Sergey [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Institut Fiziki Vysokikh Ehnergij, Protvino (Russian Federation); Bluemlein, Johannes [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Moch, Sven-Olaf [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2013-08-15

    We report recent experimental and theoretical progress concerning the heavy-quark electro-production in the context of the ABM11 parton distribution function (PDF) fit. In the updated ABM11 analysis, including the recent combined HERA charm data, the MS-values of the c-quark mass m{sub c}(m{sub c})=1.24{+-}0.03(exp){sup +0.03}{sub -0.02}(scale){sup +0.00}{sub -0.07}(th) and m{sub c}(m{sub c})=1.15{+-}0.04(exp){sup +0.04}{sub -0.00}(scale) are determined at NNLO and NLO, respectively. The values of m{sub c} obtained are compared to other determinations including the ones based on the various variable-flavor-number (VFN) scheme prescriptions.The VFN scheme uncertainties related to the matching of the 4(5)-flavor PDFs with the 3(4)-flavor ones are discussed.

  17. Effective field theory approach to heavy quark fragmentation

    CERN Document Server

    Fickinger, Michael; Kim, Chul; Mereghetti, Emanuele

    2016-01-01

    Using an approach based on Soft Collinear Effective Theory (SCET) and Heavy Quark Effective Theory (HQET) we determine the $b$-quark fragmentation function from electron-positron annihilation data at the $Z$-boson peak at next-to-next-to leading order, with next-to-next-to leading log resummation of DGLAP logarithms, and next-to-next-to-next-to leading log resummation of endpoint logarithms. This analysis improves, by one order, the previous extraction of the $b$-quark fragmentation function. We find that while the addition of the next order in the calculation does not much shift the extracted form of the fragmentation function, it does reduce theoretical errors indicating that the expansion is converging. Using an approach based on effective field theory allows us to systematically control theoretical errors. While the fits of theory to data are generally good, the fits seem to be hinting that higher order correction from HQET may be needed to explain the $b$-quark fragmentation function at smaller values of...

  18. Perturbatively stable observables in heavy-quark leptoproduction

    CERN Document Server

    Ivanov, N Ya

    2016-01-01

    We study the perturbative and parametric stability of the QCD predictions for the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ and azimuthal $\\cos(2\\varphi)$ asymmetry, $A(x,Q^2)$, in heavy-quark leptoproduction. First, we review the available theoretical results for these quantities and conclude that, contrary to the production cross sections, the ratios $R(x,Q^2)$ and $A(x,Q^2)$ are stable under radiative QCD corrections in wide region of the variables $x$ and $Q^2$. This implies that large radiative contributions to the structure functions cancel each other in the ratios $R(x,Q^2)$ and $A(x,Q^2)$ with a good accuracy. Our analysis shows that the hadron-level predictions for the Callan-Gross ratio and azimuthal asymmetry are also stable under the DGLAP evolution of the gluon density. Then we consider some experimental and phenomenological applications of the observed perturbative stability. We provide compact analytic predictions for $R(x,Q^2)$ and azimuthal $\\cos(2\\varphi)$ asymmetry in the case of low $x\\ll 1$. ...

  19. String Models for the Heavy Quark-Antiquark Bound States.

    Science.gov (United States)

    Tse, Sze-Man

    1988-12-01

    The heavy quark-antiquark bound state is examined in the phenomenological string models. Specifically, the Nambu-Goto model and the Polyakov's smooth string model are studied in the large-D limit, D being the number of transverse space-time dimensions. The static potential V(R) is extracted in both models in the large-D limit. In the former case, this amounts to the usual saddle point calculation. In the latter case, the renormalized, physical string tension is expressed in terms of the bare string tension and the extrinsic curvature coupling. A systematic loop expansion of V(R) is developed and carried out explicitly to one loop order, with the two loops result presented without detail. For large separations R, the potential is linear in R with corrections of order 1/R. The coefficient of the 1/R Luscher term has the universal value -piD/24 to any finite order in the loop expansion. For very small separations R, the potential V(R) is also proportional to 1/R with a coefficient twice that of Luscher's term. The corrections are logarithmically small. Polyakov's smooth string model is extended to the finite temperature situation. The temperature dependence of the string tension is investigated in the large-D limit. The effective string tension is calculated to the second order in the loop expansion. At low temperature, it differs from that of the Nambu-Goto model only by terms that fall exponentially with inverse temperature. Comparison of the potential V(R) in the smooth string model with lattice gauge calculation and hadron spectroscopy data yields a consistent result.

  20. T-matrix approach to heavy quark diffusion in the QGP

    Energy Technology Data Exchange (ETDEWEB)

    Hees, H. van [Justus-Liebig-Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany); Mannarelli, M. [Instituto de Ciencias del Espacio (IEEC/CSIC), Bellaterra (Barcelona) (Spain); Greco, V. [INFN-LNS, Catania (Italy); Dipartimento Interateneo di Fisica di Bari, Bari (Italy); Rapp, R. [Texas A and M University, Cyclotron Institute and Physics Department, College Station, TX (United States)

    2009-06-15

    We assess transport properties of heavy quarks in the quark-gluon plasma (QGP) using static heavy-quark (HQ) potentials from lattice-QCD calculations in a Brueckner many-body T-matrix approach to evaluate elastic heavy-quark-light-quark scattering amplitudes. In the attractive meson and diquark channels, resonance states are formed for temperatures up to {proportional_to}1.5T{sub c}, increasing pertinent drag and diffusion coefficients for heavy-quark rescattering in the QGP beyond the expectations from perturbative-QCD calculations. We use these transport coefficients, complemented with perturbative elastic HQ gluon scattering, in a relativistic Langevin simulation to obtain HQ p{sub t} distributions and elliptic flow (v{sub 2}) under conditions relevant for the hot and dense medium created in ultrarelativistic heavy-ion collisions. The heavy quarks are hadronized to open-charm and -bottom mesons within a combined quark-coalescence fragmentation scheme. The resulting single-electron spectra from their semileptonic decays are confronted with recent data on ''non-photonic electrons'' in 200 A GeV Au-Au collisions at the Relativistic Heavy-Ion Collider (RHIC). (orig.)

  1. Heavy-quark spin symmetry partners of the X(3872 revisited

    Directory of Open Access Journals (Sweden)

    V. Baru

    2016-12-01

    Full Text Available We revisit the consequences of the heavy-quark spin symmetry for the possible spin partners of the X(3872. We confirm that, if the X(3872 were a DD¯⁎ molecular state with the quantum numbers JPC=1++, then in the strict heavy-quark limit there should exist three more hadronic molecules degenerate with the X(3872, with the quantum numbers 0++, 1+−, and 2++ in line with previous results reported in the literature. We demonstrate that this result is robust with respect to the inclusion of the one-pion exchange interaction between the D mesons. However, this is true only if all relevant partial waves as well as particle channels which are coupled via the pion-exchange potential are taken into account. Otherwise, the heavy-quark symmetry is destroyed even in the heavy-quark limit. Finally, we solve the coupled-channel problem in the 2++ channel with nonperturbative pions beyond the heavy-quark limit and, contrary to the findings of previous calculations with perturbative pions, find for the spin-2 partner of the X(3872 a significant shift of the mass as well as a width of the order of 50 MeV.

  2. Heavy-quark spin symmetry partners of the X(3872) revisited

    Science.gov (United States)

    Baru, V.; Epelbaum, E.; Filin, A. A.; Hanhart, C.; Meißner, Ulf-G.; Nefediev, A. V.

    2016-12-01

    We revisit the consequences of the heavy-quark spin symmetry for the possible spin partners of the X (3872). We confirm that, if the X (3872) were a DDbar* molecular state with the quantum numbers JPC =1++, then in the strict heavy-quark limit there should exist three more hadronic molecules degenerate with the X (3872), with the quantum numbers 0++, 1+-, and 2++ in line with previous results reported in the literature. We demonstrate that this result is robust with respect to the inclusion of the one-pion exchange interaction between the D mesons. However, this is true only if all relevant partial waves as well as particle channels which are coupled via the pion-exchange potential are taken into account. Otherwise, the heavy-quark symmetry is destroyed even in the heavy-quark limit. Finally, we solve the coupled-channel problem in the 2++ channel with nonperturbative pions beyond the heavy-quark limit and, contrary to the findings of previous calculations with perturbative pions, find for the spin-2 partner of the X (3872) a significant shift of the mass as well as a width of the order of 50 MeV.

  3. Emergent Lifshitz scaling from N=4 SYM with supersymmetric heavy-quark density

    CERN Document Server

    Faedo, Anton F; Kumar, S Prem

    2014-01-01

    We consider supersymmetric configurations in Type IIB supergravity obtained by the beackreaction of fundamental strings ending on a stack of D3-branes and smeared uniformly in the three spatial directions along the D3-branes. These automatically include a distribution of D5-brane baryon vertices necessary to soak up string charge. The backgrounds are static, preserving eight supersymmetries, an SO(5) global symmetry and symmetry under spatial translations and rotations. We obtain the most general BPS configurations consistent with the symmetries. We show that the solutions to the Type IIB field equations are completely specified by a single function (the dilaton) satisfying a Poisson-like equation in two dimensions. We further find that the equation admits a class of solutions displaying Lifshitz-like scaling with dynamical critical exponent z=7. The equations also admit an asymptotically AdS_5 x S^5 solution deformed by the presence of backreacted string sources that yield a uniform density of heavy quarks i...

  4. Systematic Study of Hadronic Molecules in the Heavy-Quark Sector

    CERN Document Server

    Cleven, Martin

    2014-01-01

    In this work we study the properties of hadronic molecules in the heavy-quark sector. These have become increasingly important since from the beginning of this century a large number of states have been measured that for different reasons do not fit the predictions of simple quark models. In particular we discuss two candidates in the open charm sector, $D_{s0}^*(2317)$ and $D_{s1}(2460)$, and two candidates in the bottomonium sector, $Z_b(10610)$ and $Z_b(10650)$. Theorists have proposed different explanations for these states including tetraquarks, hybrids, hadro-quarkonia and, subject of this work, hadronic molecules. The study of these new states promises to provide insights in an important field of modern physics, the formation of matter by the strong force. Hadronic molecules are bound systems of hadrons in the same way two nucleons form the deuteron. For this the molecular states need to be located close to $S$-wave thresholds of their constituents. The dynamics of their constituents will have a signif...

  5. Supersymmetric Lifshitz-like backgrounds from N=4 SYM with heavy quark density

    Energy Technology Data Exchange (ETDEWEB)

    Faedo, Anton F.; Fraser, Benjo; Kumar, S. Prem [Department of Physics, Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom)

    2014-02-17

    We examine a class of gravity backgrounds obtained by considering the backreaction of a spatially uniform density of mutually BPS Wilson lines or heavy quarks in N=4 SUSY Yang-Mills theory. The configurations preserve eight supercharges and an SO(5) subgroup of the SO(6) R-symmetry. They are obtained by considering the (1/4)-BPS geometries associated to smeared string/D3-brane (F1-D3) intersections. We argue that for the (partially) localized intersection, the geometry exhibits a flow from AdS{sub 5}×S{sup 5} in the UV to a novel IR scaling solution displaying anisotropic Lifshitz-like scaling with dynamical critical exponent z=7, hyperscaling violation and a logarithmic running dilaton. We also obtain a two-parameter family of smeared (1/4)-BPS solutions on the Coulomb branch of N=4 SYM exhibiting Lifshitz scaling and hyperscaling violation. For a certain parametric range these yield IR geometries which are conformal to AdS{sub 2}×ℝ{sup 3}, and which have been argued to be relevant for fermionic physics.

  6. Polyakov loop and heavy quark entropy in strong magnetic fields from holographic black hole engineering

    CERN Document Server

    Critelli, Renato; Finazzo, Stefano I; Noronha, Jorge

    2016-01-01

    We investigate the temperature and magnetic field dependence of the Polyakov loop and heavy quark entropy in a bottom-up Einstein-Maxwell-dilaton (EMD) holographic model for the strongly coupled quark-gluon plasma (QGP) that quantitatively matches lattice data for the $(2+1)$-flavor QCD equation of state at finite magnetic field and physical quark masses. We compare the holographic EMD model results for the Polyakov loop at zero and nonzero magnetic fields and the heavy quark entropy at vanishing magnetic field with the latest lattice data available for these observables and find good agreement for temperatures $T\\gtrsim 150$ MeV and magnetic fields $eB\\lesssim 1$ GeV$^2$. Predictions for the behavior of the heavy quark entropy at nonzero magnetic fields are made that could be readily tested on the lattice.

  7. Screening of heavy quarks and hadrons at finite temperature and density

    Energy Technology Data Exchange (ETDEWEB)

    Doering, M.

    2006-09-22

    Heavy quarks and hadrons placed in a strongly interacting thermal and baryon chemical quantum field are screened by the medium. I calculate the free energies of heavy quarks and anti-quarks and hadron correlation functions on a 16{sup 3} x 4 lattice in 2-flavour QCD with a bare quark mass of m/T=0.4. The dependence on the interparticle distance determines the screening masses as a function of temperature and density. The Taylor expansion method is used for the baryon chemical potential. The heavy quark screening masses turn out to be in good agreement with perturbation theory for temperatures T>2T{sub c}. The hadron screening masses are consistent with the free quark propagation in the large temperature regime. (orig.)

  8. Additional information on heavy quark parameters from charged lepton forward-backward asymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Turczyk, Sascha [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,55099 Mainz (Germany)

    2016-04-20

    The determination of |V{sub cb}| using inclusive and exclusive (semi-)leptonic decays exhibits a long-standing tension of varying O(3σ) significance. For the inclusive determination the decay rate is expanded in 1/m{sub b} using heavy quark expansion, and from moments of physical observables the higher order heavy quark parameters are extracted from experimental data in order to assess |V{sub cb}| from the normalisation. The drawbacks are high correlations both theoretically as well as experimentally among these observables. We will scrutinise the inclusive determination in order to add a new and less correlated observable. This observable is related to the decay angle of the charged lepton and can help to constrain the important heavy quark parameters in a new way. It may validate the current seemingly stable extraction of |V{sub cb}| from inclusive decays or hints to possible issues, and even may be sensitive to New Physics operators.

  9. A way to estimate the heavy quark thermalization rate from the lattice

    CERN Document Server

    Caron-Huot, Simon; Moore, Guy D

    2009-01-01

    The thermalization rate of a heavy quark is related to its momentum diffusion coefficient. Starting from a Kubo relation and using the framework of the heavy quark effective theory, we argue that in the large-mass limit the momentum diffusion coefficient can be defined through a certain Euclidean correlation function, involving color-electric fields along a Polyakov loop. Furthermore, carrying out a perturbative computation, we show that the spectral function corresponding to this correlator is relatively flat at small frequencies. Therefore, unlike in the case of several other transport coefficients, for which the narrowness of the transport peak makes analytic continuation from Euclidean lattice data susceptible to severe systematic uncertainties, it appears that the determination of the heavy quark thermalization rate could be relatively well under control.

  10. Additional Information on Heavy Quark Parameters from Charged Lepton Forward-Backward Asymmetry

    CERN Document Server

    Turczyk, Sascha

    2016-01-01

    The determination of $|V_{cb}|$ using inclusive and exclusive (semi-)leptonic decays exhibits a long-standing tension of varying ${\\cal O}(3 \\sigma)$ significance. For the inclusive determination the decay rate is expanded in $1/m_b$ using heavy quark expansion, and from moments of physical observables the higher order heavy quark parameters are extracted from experimental data in order to assess $|V_{cb}|$ from the normalisation. The drawbacks are high correlations both theoretically as well as experimentally among these observables. We will scrutinise the inclusive determination in order to add a new and less correlated observable. This observable is related to the decay angle of the charged lepton and can help to constrain the important heavy quark parameters in a new way. It may validate the current seemingly stable extraction of $|V_{cb}|$ from inclusive decays or hints to possible issues, and even may be sensitive to New Physics operators.

  11. Specific Features of Heavy Quark Production. LPHD approach to heavy particle spectra

    OpenAIRE

    Dokshitzer, Yu. L.; Khoze, V. A.; Troyan, S. I.

    1995-01-01

    Perturbative QCD formula for inclusive energy spectra of heavy quarks from heavy quark initiated jets which takes into account collinear and/or soft logarithms in all orders, the exact first order result and two-loop effects is applied to distributions of heavy flavoured hadrons in the framework of the LPHD concept. Fits to experimentally measured charm and bottom mean energy losses result in $\\alpha_{\\MSbar}(M_Z)=0.125\\pm 0.003\\pm 0.004$ and $(2\\GeV)^{-1}\\int_0^{2\\GeV} dk \\alpha_s^{eff}(k)= ...

  12. Introduction to non-perturbative heavy quark effective theory

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, R. [DESY, Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2010-08-15

    My lectures on the effective field theory for heavy quarks, an expansion around the static limit, concentrate on the motivation and formulation of HQET, its renormalization and discretization. This provides the basis for understanding that and how this effective theory can be formulated fully non-perturbatively in the QCD coupling, while by the very nature of an effective field theory, it is perturbative in the expansion parameter 1/m. After the couplings in the effective theory have been determined, the result at a certain order in 1/m is unique up to higher order terms in 1/m. In particular the continuum limit of the lattice regularized theory exists and leaves no trace of how it was regularized. In other words, the theory yields an asymptotic expansion of the QCD observables in 1/m - as usual in a quantum field theory modified by powers of logarithms. None of these properties has been shown rigorously (e.g. to all orders in perturbation theory) but perturbative computations and recently also non-perturbative lattice results give strong support to this ''standard wisdom''. A subtle issue is that a theoretically consistent formulation of the theory is only possible through a non-perturbative matching of its parameters with QCD at finite values of 1/m. As a consequence one finds immediately that the splitting of a result for a certain observable into, for example, lowest order and first order is ambiguous. Depending on how the matching between effective theory and QCD is done, a first order contribution may vanish and appear instead in the lowest order. For example, the often cited phenomenological HQET parameters anti {lambda} and {lambda}{sub 1} lack a unique non-perturbative definition. But this does not affect the precision of the asymptotic expansion in 1/m. The final result for an observable is correct up to order (1/m){sup n+1} if the theory was treated including (1/m){sup n} terms. Clearly, the weakest point of HQET is that it

  13. Large-p heavy-quark production in two-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Cacciari, M.; Kramer, M. [DESY-Deutsches Elektronen-Synchrotron, Hamburg (Germany); Greco, M. [Rome Univ. III (Italy). Dip. di Fisica]|[INFN, Laboratori Nazionali di Frascati, Rome (Italy); Kniehl, B.A. [Max-Planck-Institut fuer Physik, Munich (Germany)

    1995-11-01

    The next-to-leading-order (NLO) cross section for the production of heavy quarks at large transverse momenta {gamma}{gamma} collision is calculated with perturbative fragmentation functions (PFF). This approach allows for a resummation of terms {proportional_to} {alpha}{sub s}ln(p{sup 2}/m{sup 2}) which arise in NLO from collinear emission of gluons by a heavy quark at large p or from almost collinear branching of photons or gluons into heavy-quark pairs. It is presented single-inclusive distributions in p and rapidity including direct and resolved photons for {gamma}{gamma} production of heavy quarks at e{sup +}e{sup -} colliders and at high-energy {gamma}{gamma} colliders. The results are compared with fixed- order calculation for m finite including QDC radiative corrections. The two approaches differ in the definitions and relative contributions of the direct and resolved terms, but essentially agree in their sum. The resummation of the {alpha}{sub s}ln(p{sup 2}/m{sup 2}) terms in the PFF approach leads to a softer p distribution and to reduced sensitivity to the choice of the renormalization and factorization scales.

  14. On specific QCD properties of heavy quark fragmentation ('dead cone')

    Energy Technology Data Exchange (ETDEWEB)

    Dokshitzer, Yu.L.; Khoze, V.A.; Troyan, S.I. (Lund Univ. (Sweden). Dept. of Theoretical Physics AN SSSR, Leningrad (USSR). Inst. Yadernoj Fiziki)

    1991-10-01

    It is the restriction on the phase space of emitting gluons connected with the kinematics of a heavy quark Q = c,b, ... which determines the difference of the QCD jet produced by Q from that of ordinary light (practically massless) quarks q = u,d,s. (author).

  15. Heavy quark quenching from RHIC to LHC and the consequences of gluon damping

    Science.gov (United States)

    Gossiaux, P. B.; Nahrgang, M.; Bluhm, M.; Gousset, Th.; Aichelin, J.

    2013-05-01

    In this contribution to the Quark Matter 2012 conference, we study whether energy loss models established for RHIC energies to describe the quenching of heavy quarks can be applied at LHC with the same success. We also benefit from the larger pT-range accessible at this accelerator to test the impact of gluon damping on observables such as the nuclear modification factor.

  16. Heavy quark quenching from RHIC to LHC and the consequences of gluon damping

    OpenAIRE

    Gossiaux, Pol Bernard; Nahrgang, Marlene; Bluhm, Marcus; Gousset, Thierry; Aichelin, Joerg

    2012-01-01

    In this contribution to the Quark Matter 2012 conference, we study whether energy loss models established for RHIC energies to describe the quenching of heavy quarks can be applied at LHC with the same success. We also benefit from the larger $p_T$-range accessible at this accelerator to test the impact of gluon damping on observables such as the nuclear modification factor.

  17. Gauge cooling in complex Langevin for lattice QCD with heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Erhard, E-mail: ehs@mppmu.mpg.de [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München (Germany); Sexty, Dénes, E-mail: d.sexty@thphys.uni-heidelberg.de [Institut für Theoretische Physik, Universität Heidelberg (Germany); Stamatescu, Ion-Olimpiu, E-mail: I.O.Stamatescu@thphys.uni-heidelberg.de [Institut für Theoretische Physik, Universität Heidelberg (Germany)

    2013-06-10

    We employ a new method, “gauge cooling”, to stabilize complex Langevin simulations of QCD with heavy quarks. The results are checked against results obtained with reweighting; we find agreement within the estimated errors, except for strong gauge coupling in the confinement region. The method allows us to go to previously unaccessible high densities.

  18. Heavy quark jets as technicolour signatures in pp and panti p collisions

    Energy Technology Data Exchange (ETDEWEB)

    Girardi, G.; Sorba, P. (Grenoble-1 Univ., 74 - Annecy (France). Lab. de Physique des Particules); Mery, P. (European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.)

    1982-02-22

    Within the framework of technicolour models many heavy bosons are expected. In this paper we propose heavy quark jets as a good way to find some of these particles. Our calculation suggest that the collider at BNL is the most adequate machine for such hunting.

  19. Effective field theories for baryons with two- and three-heavy quarks

    CERN Document Server

    Vairo, Antonio

    2010-01-01

    Baryons made of two or three heavy quarks can be described in the modern language of non-relativistic effective field theories. These, besides allowing a rigorous treatment of the systems, provide new insight in the nature of the three-body interaction in QCD.

  20. Implications of a High-Mass Diphoton Resonance for Heavy Quark Searches

    CERN Document Server

    Banerjee, Shankha; Bélanger, Geneviève; Delaunay, Cédric

    2016-01-01

    Heavy vector-like quarks coupled to a scalar $S$ will induce a coupling of this scalar to photons and/or gluons. The decay of the heavy quark into $Sq$, with $q$ being a SM quark, could provide a new search channel for heavy quarks. For illustration, we consider the case of a singlet vector-like partner of the top quark and show that it can be searched for at the 13 TeV LHC through its decay into a scalar resonance in the $2\\gamma+\\ell$ final state, especially if the diphoton branching ratio of the scalar $S$ is further enhanced by the contribution of non coloured particles. We focus on the case where the scalar has a mass of 750 GeV, compatible with the recently reported diphoton excess at the LHC. We further show that conventional heavy quark searches can be sensitive to this new decay pattern also when $S$ decays into jets by slightly tightening the current selection cuts. Finally we comment about the possibility of disentangling the heavy quark decay to $St$ from other standard decay patterns by scrutinis...

  1. Baryons and baryonic matter in the large Nc and heavy quark limits

    CERN Document Server

    Cohen, Thomas D; Ndousse, Kamal K

    2011-01-01

    This paper explores properties of baryons and finite density baryonic matter in an artificial world in which Nc, the number of colors, is large and the quarks of all species are degenerate and much larger than {\\Lambda}_QCD. It has long been known that in large Nc QCD, baryons composed entirely of heavy quarks are accurately described in the mean-field approximation. However, the detailed properties of baryons in the combined large Nc and heavy quark limits have not been fully explored. Here some basic properties of baryons are computed using a variational approach. At leading order in both the large Nc and heavy quark expansions the baryon mass is computed explicitly as is the baryon form factor. Baryonic matter, the analog of nuclear matter in this artificial world, should also be well described in the mean-field approximation. In the special case where all baryons have an identical spin flavor structure, it is shown that in the formal heavy quark and large Nc limit interactions between baryons are strictly...

  2. Asymmetries in Heavy Quark Pair and Dijet Production at an EIC

    NARCIS (Netherlands)

    Boer, Daniël; Mulders, Piet J.; Pisano, Cristian; Zhou, Jian

    2016-01-01

    Asymmetries in heavy quark pair and dijet production in electron-proton collisions allow studies of gluon TMDs in close analogy to studies of quark TMDs in semi-inclusive DIS. Here we present expressions for azimuthal asymmetries for both unpolarized and transversely polarized proton cases and consi

  3. Hidden beauty baryon states in the local hidden gauge approach with heavy quark spin symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, C.W.; Oset, E. [Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Valencia (Spain)

    2013-11-15

    Using a coupled-channel unitary approach, combining the heavy quark spin symmetry and the dynamics of the local hidden gauge, we investigate the meson-baryon interaction with hidden beauty and obtain several new states of N around 11 GeV. We consider the basis of states {eta}{sub b} N, {Upsilon};N, B {Lambda}{sub b}, B {Sigma}{sub b}, B{sup *}{Lambda}{sub b}, B{sup *}{Sigma}{sub b}, B{sup *}{Sigma}{sub b}{sup *} and find four basic bound states which correspond to B {Sigma}{sub b}, B {Sigma}{sub b}{sup *}, B{sup *}{Sigma}{sub b} and B{sup *}{Sigma}{sub b}{sup *}, decaying mostly into {eta}{sub b} N and {Upsilon}N and with a binding energy about 50-130 MeV with respect to the thresholds of the corresponding channel. All of them have isospin I = 1/2, and we find no bound states or resonances in I = 3/2. The B {Sigma}{sub b} state appears in J = 1/2, the B {Sigma}{sub b}{sup *} in J = 3/2, the B{sup *}{Sigma}{sub b} appears nearly degenerate in J = 1/2, 3/2 and the B{sup *}{Sigma}{sub b}{sup *} appears nearly degenerate in J = 1/2, 3/2, 5/2. These states have a width from 2-110 MeV, with conservative estimates of uncertainties, except for the one in J = 5/2 which has zero width since it cannot decay into any of the states of the basis chosen. We make generous estimates of the uncertainties and find that within very large margins these states appear bound. (orig.)

  4. Heavy quark production in $pA$ collisions: the double parton scattering contribution

    CERN Document Server

    Cazaroto, E R; Navarra, F S

    2016-01-01

    In this paper we estimate the double parton scattering (DPS) contribution for the heavy quark production in $pA$ collisions at the LHC. The cross sections for the charm and bottom production are estimated using the dipole approach and taking into account the saturation effects, which are important for high energies and for the scattering with a large nucleus. We compare the DPS contribution with the single parton scattering one and demonstrate that both are similar in the kinematical range probed by the LHC. Predictions for the rapidity range analysed by the LHCb Collaboration are also presented. Our results indicate that the study of the DPS contribution for the heavy quark production in $pPb$ collisions at the LHC is feasible and can be useful to probe the main assumptions of the approach.

  5. Heavy quark production in photon-Pomeron interactions at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Machado, M. M. [Instituto Federal de Ciencia, Educacao e Tecnologia Farroupilha, Campus Sao Borja, Rua Otaviano Castilho Mendes, 355, CEP 97670-000, Sao Borja, RS (Brazil); Goncalves, V. P. [Instituto de Fisica e Matematica - IFM, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, RS (Brazil)

    2013-03-25

    The diffractive heavy quark cross sections are estimated considering photon-Pomeron interactions in hadron - hadron at RHIC, Tevatron, and CERN LHC energies. We assume the validity of the hard diffractive factorization and calculate the charm and bottom total cross sections and rapidity distributions using the diffractive parton distribution functions of the Pomeron obtained by the H1 Collaboration at DESY-HERA. Such processes are sensitive to the gluon content of the Pomeron at high energies and are a good place to constrain the behavior of this distribution. We also compare our predictions with those obtained using the dipole model, and verify that these processes are a good test of the different mechanisms for heavy quarks diffractive production at hadron colliders.

  6. Specific features of heavy quark production local parton-hadron duality approach to heavy particle spectra

    CERN Document Server

    Dokshitzer, Yu L; Troyan, S I

    1996-01-01

    Perturbative QCD formula for inclusive energy spectra of heavy quarks from heavy quark initiated jets which takes into account collinear and/or soft logarithms in all orders, the exact first order result and two-loop effects is applied to distributions of heavy flavoured hadrons in the framework of the LPHD concept. Fits to experimentally measured charm and bottom mean energy losses result in \\alpha_{\\MSbar}(M_Z)=0.125\\pm 0.003\\pm 0.004 and (2\\GeV)^{-1}\\int_0^{2\\GeV} dk \\alpha_s^{eff}(k)= 0.18\\pm 0.01\\pm 0.02 with \\alpha_s^{eff} an infrared finite effective QCD coupling.

  7. Heavy-Quark Spin Symmetry Partners of the X(3872) Molecule

    Science.gov (United States)

    Baru, V.; Epelbaum, E.; Filin, A. A.; Hanhart, C.; Nefediev, A. V.

    Heavy quark spin symmetry (HQSS) partners of the X(3872) JPC = 1++ molecule are discussed in a coupled-channel approach with non-perturbative pions. In the strict heavy-quark limit the 1++ molecular state has three degenerate partner states with the 1+-, 0++, and 2++ quantum numbers. In the presence of pions this result is shown to be correct only if all allowed coupled-channel transitions between the Dbar{D}, D bar{D}nolimits*, and D* bar{D}nolimits* channels governed by the one-pion exchange potential are included. In particular, it is demonstrated that neglecting some of the coupled-channel transitions leads to a severe violation of HQSS as well as to regulator-dependent results for the partner states. The effect of HQSS violations by the D*-D mass difference on the properties of the 2++ partner state of the X(3872) is also discussed.

  8. Kondo cloud of single heavy quark in cold and dense matter

    CERN Document Server

    Yasui, Shigehiro

    2016-01-01

    The Kondo effect is a universal phenomena observed in a variety of fermion systems containing a heavy impurity particle whose interaction is governed by the non-Abelian interaction. At extremely high density, I study the Kondo effect by color exchange in quark matter containing a single heavy (charm or bottom) quark as an impurity particle. To obtain the ground state with the Kondo effect, I introduce the condensate mixing the light quark and the heavy quark (Kondo cloud) in the mean-field approximation. I estimate the energy gain by formation of the Kondo cloud, and present that the Kondo cloud exhibits the resonant structure. I also evaluate the scattering cross section for the light quark and the heavy quark, and discuss its effect to the finite size quark matter.

  9. Collisional Energy Loss of a Heavy Quark in an Anisotropic Quark-Gluon Plasma

    CERN Document Server

    Romatschke, P; Romatschke, Paul; Strickland, Michael

    2004-01-01

    We compute the leading-order collisional energy loss of a heavy quark propagating through a quark-gluon plasma in which the quark and gluon distributions are anisotropic in momentum space. Following the calculation outlined for QED in an earlier work we indicate the differences encountered in QCD and their effect on the collisional energy loss results. For a 20 GeV bottom quark we show that momentum space anisotropies can result in the collisional heavy quark energy loss varying with the angle of propagation by up to 50%. For low velocity quarks we show that anisotropies result in energy gain instead of energy loss with the energy gain focused in such a way as to accelerate particles along the anisotropy direction thereby reducing the momentum-space anisotropy. The origin of this negative energy loss is explicitly identified as being related to the presence of plasma instabilities in the system.

  10. Kondo cloud of single heavy quark in cold and dense matter

    Science.gov (United States)

    Yasui, Shigehiro

    2017-10-01

    The Kondo effect is a universal phenomena observed in a variety of fermion systems containing a heavy impurity particle whose interaction is governed by the non-Abelian interaction. At extremely high density, I study the Kondo effect by color exchange in quark matter containing a single heavy (charm or bottom) quark as an impurity particle. To obtain the ground state with the Kondo effect, I introduce the condensate mixing the light quark and the heavy quark (Kondo cloud) in the mean-field approximation. I estimate the energy gain by formation of the Kondo cloud, and present that the Kondo cloud exhibits the resonant structure. I also evaluate the scattering cross section for the light quark and the heavy quark, and discuss its effect to the finite size quark matter.

  11. Heavy Quark Potential at Finite Temperature in a Dual Gravity Closer to Large N QCD

    CERN Document Server

    Patra, Binoy Krishna

    2014-01-01

    In gauge-gravity duality, heavy quark potential at finite temperature is usually calculated with the pure AdS background, which does not capture the renormalisation group (RG) running in the gauge theory part and the potential also does not contain any confining term in the deconfined phase. Following the developments in \\cite{KS}, a geometry was contructed recently in \\cite{ Mia:NPB2010, Mia:PRD2010}, which captures the RG flow similar to QCD and we employ their geometry to obtain the heavy quark potential by analytically continuing the string configurations into the complex plane. In addition to the attractive terms, the obtained potential has confining terms both at $T=0$ and $T \

  12. Phase structure of finite temperature QCD in the heavy quark region

    CERN Document Server

    Saito, H; Aoki, S; Hatsuda, T; Kanaya, K; Maezawa, Y; Ohno, H; Umeda, T

    2011-01-01

    We study the quark mass dependence of the finite temperature QCD phase transition in the heavy quark region using an effective potential defined through the probability distribution function of the average plaquette. Performing a simulation of SU(3) pure gauge theory, we first confirm that the distribution function has two peaks indicating that the phase transition is of first order in the heavy quark limit, while the first order transition turns into a crossover as the quark mass decreases from infinity, where the mass dependence of the distribution function is evaluated by the reweighting method combined with the hopping parameter expansion. We determine the endpoint of the first order transition region for N_f=1, 2, 3 and 2+1 cases. The quark mass dependence of the latent heat is also evaluated in the first order transition region.

  13. Radiative Energy Loss of Heavy Quark and Dead Cone Effect in Ultra-relativistic Heavy Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    XIANG Wen-Chang; DING Heng-Tong; ZHOU Dai-Cui

    2005-01-01

    @@ The lowest-order heavy quark radiative energy loss has been analysed to quantify the dead cone effect. The medium-induced gluon radiation is found to fill the dead cone, it is reduced at large gluon energies compared to the radiation of light quarks. We calculate the radiative energy loss of heavy quarks in the condition of dead cone effect. It is found that the radiative energy loss with dead cone effect is smaller than that without the dead cone effect.

  14. Heavy quark hadroproduction as a test of the effective BFKL quark-antiquark-vertex

    CERN Document Server

    Hagler, P; Schäfer, A; Szymanowski, L; Teryaev, O V; Hagler, Ph.

    2000-01-01

    We calculate heavy quark pair hadroproduction in the framework of thek_t-factorization approach. The quark pair production in the quasi multi Reggekinematics is described by an effective vertex which is a part of thenext-to-leading corrections to the BFKL kernel. We find very good agreement ofour results with the existing data for bottom-antibottom production. Inaddition we present predictions for LHC.

  15. Operator product expansion for inclusive semileptonic decays in heavy quark effective field theory

    CERN Document Server

    Mannel, T

    1994-01-01

    Inclusive semileptonic decays are discussed in the framework of heavy quark effective field theory by employing the short distance expansion in the effective theory. The lowest order term turns out to be the parton model; the higher order terms may be regarded as correction terms to the parton model result. The first nonvanishing corrections to the parton model result are given and the lepton energy spectrum of inclusive semileptonic decays of heavy mesons is calculated.

  16. Heavy quark photoproduction in the semihard approach at HERA and beyond

    CERN Document Server

    Saleev, V A

    1995-01-01

    Processes of heavy quark photoproduction at HERA energies and beyond are investigated using the semihard (k_{\\bot} factorization) approach. Virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small x have been taken into account. The total cross sections, rapidity and p_{\\bot} distributions of the charm and beauty quark photoproduction have been calculated. The results are compared with ZEUS experimental data for charm photoproduction cross section.

  17. Remarks on sum rules in the heavy quark limit of QCD

    CERN Document Server

    Le Yaouanc, A; Pène, O; Raynal, J C; Morénas, V

    2001-01-01

    We underline a problem existing in the heavy quark limit of QCD concerning the rates of semileptonic B decays into P-wave $D_J(j)$ mesons, where $j = {1 \\over 2}$ (wide states) or $j = {3 \\over 2}$ (narrow states). The leading order sum rules of Bjorken and Uraltsev suggest $\\Gamma [ \\bar{B} \\to D_{0,1} ({1 \\over 2}) \\ell \

  18. On P-wave meson decay constants in the heavy quark limit of QCD

    CERN Document Server

    Le Yaouanc, A; Pène, O; Raynal, J C; Morénas, V

    2001-01-01

    In previous work it has been shown that, either from a sum rule for the subleading Isgur-Wise function $\\xi_3(1)$ or from a combination of Uraltsev and Bjorken SR, one infers for $P$-wave states $|\\tau_{1/2}(1)| \\ll |\\tau_{3/2}(1)|$. This implies, in the heavy quark limit of QCD, a hierarchy for the {\\it production} rates of $P$-states $\\Gamma(\\bar{B}_d \\to D ({1 \\over 2}) \\ell \

  19. A review of the intrinsic heavy quark content of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kusina, A. [Univ. Grenoble-Alpes, Grenoble (France); Lyonnet, F. [Southern Methodist Univ., Dallas, TX (United States); Schienbein, I. [Univ. Grenoble-Alpes, Grenoble (France); Spiesberger, H. [Johannes Gutenberg Univ., Mainz (Germany); Vogt, R. [Univ. of California at Davis, Davis, CA (United States)

    2015-04-29

    We present a review of the state of the art of our understanding of the intrinsic charm and bottom content of the nucleon. We discuss theoretical calculations, constraints from global analyses, and collider observables sensitive to the intrinsic heavy quark distributions. In addition, a particular emphasis is put on the potential of a high energy and high luminosity fixed target experiment using the LHC beams (AFTER@LHC) to search for intrinsic charm.

  20. Recent results on heavy quark quenching in ultrarelativistic heavy ion collisions

    CERN Document Server

    Gossiaux, Pol Bernard; Bluhm, Marcus; Gousset, Thierry; Nahrgang, Marlene; Vogel, Sascha; Werner, Klaus

    2012-01-01

    In this contribution, we present some predictions for the production of D and B mesons in ultrarelativistic heavy ion collisions at RHIC and LHC energies and confront them with experimental results obtained so far by the STAR, PHENIX, ALICE and CMS collaborations. We next discuss some preliminary results obtained with an improved description of the medium based on EPOS initial conditions, and its possible implications on the nuclear modification factor and on the elliptic flow of heavy quarks.

  1. Radiative corrections to all charge assignments of heavy quark baryon semileptonic decays

    CERN Document Server

    Martínez, A; García, A; Flores-Mendieta, R; Flores-Mendieta, Ruben

    2002-01-01

    In semileptonic decays of spin-1/2 baryons containing heavy quarks up to six charge assignments for the baryons and lepton are possible. We show that the radiative corrections to four of these possibilities can be directly obtained from the final results of the two possibilities previously studied. There is no need to recalculate integrals over virtual or real photon momentum or any traces.

  2. Toward a solution to the $R_{AA}$ and $v_2$ puzzle for heavy quarks

    CERN Document Server

    Das, Santosh K; Plumari, Salvatore; Greco, Vincenzo

    2015-01-01

    The heavy quarks constitutes a unique probe of the quark-gluon plasma properties. Both at RHIC and LHC energies a puzzling relation between the nuclear modification factor $R_{AA}(p_T)$ and the elliptic flow $v_2(p_T)$ has been observed which challenged all the existing models, especially for D mesons. We discuss how the temperature dependence of the heavy quark drag coefficient is responsible to address for a large part of such a puzzle. In particular, we have considered four different models to evaluate the temperature dependence of drag and diffusion coefficients propagating through a quark gluon plasma (QGP). All the four different models are set to reproduce the same $R_{AA}(p_T)$ observed in experiments at RHIC and LHC energy. We point out that for the same $R_{AA}(p_T)$ one can generate 2-3 times more $v_2$ depending on the temperature dependence of the heavy quark drag coefficient. An increasing drag coefficient as $ T \\rightarrow\\ T_c \\,$ is a major ingredient for a simultaneous description of $R_{AA...

  3. Toward a solution to the RAA and v2 puzzle for heavy quarks

    Directory of Open Access Journals (Sweden)

    Santosh K. Das

    2015-07-01

    Full Text Available The heavy quarks constitute a unique probe of the quark–gluon plasma properties. A puzzling relation between the nuclear modification factor RAA(pT and the elliptic flow v2(pT has been observed both at RHIC and LHC energies. Predicting correctly both observables has been a challenge to all existing models, especially for D mesons. We discuss how the temperature dependence of the heavy quark drag coefficient is responsible for a large part of such a puzzle. In particular, we have considered four different models to evaluate the temperature dependence of drag and diffusion coefficients propagating through a quark gluon plasma (QGP. All the four different models are set to reproduce the same RAA(pT observed in experiments at RHIC and LHC energy. We point out that for the same RAA(pT one can generate 2–3 times more v2 depending on the temperature dependence of the heavy quark drag coefficient. A non-decreasing drag coefficient as T→Tc is a major ingredient for a simultaneous description of RAA(pT and v2(pT.

  4. Higher order and heavy quark mass effects in the determination of parton distribution functions

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, Valerio

    2013-07-01

    The present thesis was devoted to the study of the inclusion of higher-order corrections and heavy quark mass effects in a PDF determination. This has been carried out in the NNPDF framework resulting originally in the NNPDF2.1 sets, which were at a later stage supplemented by the first LHC data leading to the most recent NNPDF2.3 sets. In Chapter 1 the concept of Parton Distribution Function (PDF) was introduced. We have shown how the analytical computation of the Deep-Inelastic-Scattering (DIS) process at order α{sub s} in QCD leads to initial-stale collinear divergences which, using the factorization theorem, can be reabsorbed into the PDFs. The energy dependence of PDFs is fully determined and the task is then reduced to the determination of the x (Bjorken variable) dependence. In Chapter 2 a detailed discussion of the factorization schemes presently available to include heavy quark mass effects into DIS structure functions has been given. It emerged that there are two possible basic approaches to the calculation of the DIS structure functions. In the first approach, the so-called Fixed-Flavour-Number Scheme (FFNS), the calculation is performed retaining the quark mass of the heavy flavours which provide a ''natural'' regulator for the infrared divergences. In the second approach, called Zero-Mass Variable-Flavour-Number Scheme (ZM-VFNS), the heavy quark masses are instead set to zero and this gives rise to the usual final-state collinear divergences that are absorbed into the PDFs. In addition, in the ZM-VFNS, the number of active flavours is assumed to increase by one unity as the energy of the process crosses the energy threshold of a given heavy quark. In order to obtain a factorization scheme that is accurate both at large and low energies, several prescriptions that interpolate between FFNS at low energy and ZM-VFNS at large energy have been proposed and implemented in as many PDF fits. In Chapter 2 they have been described showing

  5. The pole mass of the heavy quark Perturbation theory and beyond

    CERN Document Server

    Bigi, Ikaros I; Uraltsev, N; Vainshtein, A I

    1994-01-01

    The key quantity of the heavy quark theory is the quark mass m.sub(Q). Since quarks are unobservable one can suggest different definitions of m.sub(Q). One of the most popular choices is the pole quark mass routinely used in perturbative calculations and in some analyses based on heavy quark expansions. We show that no precise definition of the pole mass can be given in the full theory once non-perturbative effects are included. Any definition of this quantity suffers from an intrinsic uncertainty of order $\\Lam m.sub(Q). This fact is succinctly described by the existence of an infrared renormalon generating a factorial divergence in the high-order coefficients of the .alpha.sub(s) series; the corresponding singularity in the Borel plane is situated at $2\\pi /b$. A peculiar feature is that this renormalon is not associated with the matrix element of a local operator. The difference $\\La \\equiv M_{H_Q}-m_Q^{pole}$ can still be defined in Heavy Quark Effective Theory, but only at the price of introducing an exp...

  6. Higher order and heavy quark mass effects in the determination of parton distribution functions

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, Valerio

    2013-07-01

    The present thesis was devoted to the study of the inclusion of higher-order corrections and heavy quark mass effects in a PDF determination. This has been carried out in the NNPDF framework resulting originally in the NNPDF2.1 sets, which were at a later stage supplemented by the first LHC data leading to the most recent NNPDF2.3 sets. In Chapter 1 the concept of Parton Distribution Function (PDF) was introduced. We have shown how the analytical computation of the Deep-Inelastic-Scattering (DIS) process at order α{sub s} in QCD leads to initial-stale collinear divergences which, using the factorization theorem, can be reabsorbed into the PDFs. The energy dependence of PDFs is fully determined and the task is then reduced to the determination of the x (Bjorken variable) dependence. In Chapter 2 a detailed discussion of the factorization schemes presently available to include heavy quark mass effects into DIS structure functions has been given. It emerged that there are two possible basic approaches to the calculation of the DIS structure functions. In the first approach, the so-called Fixed-Flavour-Number Scheme (FFNS), the calculation is performed retaining the quark mass of the heavy flavours which provide a ''natural'' regulator for the infrared divergences. In the second approach, called Zero-Mass Variable-Flavour-Number Scheme (ZM-VFNS), the heavy quark masses are instead set to zero and this gives rise to the usual final-state collinear divergences that are absorbed into the PDFs. In addition, in the ZM-VFNS, the number of active flavours is assumed to increase by one unity as the energy of the process crosses the energy threshold of a given heavy quark. In order to obtain a factorization scheme that is accurate both at large and low energies, several prescriptions that interpolate between FFNS at low energy and ZM-VFNS at large energy have been proposed and implemented in as many PDF fits. In Chapter 2 they have been described showing

  7. Heavy meson masses and decay constants from relativistic heavy quarks in full lattice QCD

    CERN Document Server

    McNeile, C; Follana, E; Hornbostel, K; Lepage, G P

    2012-01-01

    We determine masses and decay constants of heavy-heavy and heavy-charm pseudoscalar mesons as a function of heavy quark mass using a fully relativistic formalism known as Highly Improved Staggered Quarks for the heavy quark. We are able to cover the region from the charm quark mass to the bottom quark mass using MILC ensembles with lattice spacing values from 0.15 fm down to 0.044 fm. We obtain f_{B_c} = 0.427(6) GeV; m_{B_c} = 6.285(10) GeV and f_{\\eta_b} = 0.667(6) GeV. Our value for f_{\\eta_b} is within a few percent of f_{\\Upsilon} confirming that spin effects are surprisingly small for heavyonium decay constants. Our value for f_{B_c} is significantly lower than potential model values being used to estimate production rates at the LHC. We discuss the changing physical heavy-quark mass dependence of decay constants from heavy-heavy through heavy-charm to heavy-strange mesons. A comparison between the three different systems confirms that the B_c system behaves in some ways more like a heavy-light system t...

  8. New Heavy Quark Limit Sum Rules involving Isgur-Wise Functions and Decay Constants

    CERN Document Server

    Yaouanc, A L; Pène, O; Raynal, J C

    1996-01-01

    We consider the dominant $c\\bar{c}$ contribution to $\\Delta \\Gamma$ for the $B_s^0$-$\\bar{B}_s^0$ system in the heavy quark limit for both $b$ and $c$ quarks. In analogy with the Bjorken-Isgur-Wise sum rule in semileptonic heavy hadron decay, we impose duality between the parton model calculation of $\\Delta $m_c/m_b$ and assuming factorization and saturation by narrow resonances $(N_c $f^{(n)}_{1/2}$ ($n$ stands for any radial excitation). Alternatively, we deduce the sum rules with another method free of the factorization hypothesis, from the saturation of the expectation value of a product of two currents by heavy hadrons and by the corresponding free quarks. The sum rules read for all $w$. Moreover, we obtain, in the heavy quark limit, $f^{(n)}_{3/2} = 0$. As a consequence, unlike the BIW sum rule, the slope of the elastic function $\\xi (w)$ is related to radial excitations alone. These are generalizations, rigorous for QCD in the heavy quark limit, of results that have an easy understanding in the non-rel...

  9. The errant life of a heavy quark in the quark-gluon plasma

    CERN Document Server

    Meyer, Harvey B

    2010-01-01

    In the high-temperature phase of QCD, the heavy quark momentum diffusion constant determines, via a fluctuation-dissipation relation, how fast a heavy quark kinetically equilibrates. This transport coefficient can be extracted from thermal correlators via a Kubo formula. We present a lattice calculation of the relevant Euclidean correlators in the gluon plasma, based on a recent formulation of the problem in heavy-quark effective field theory (HQET). We find a $\\approx20%$ enhancement of the Euclidean correlator at maximal time separation as the temperature is lowered from $6T_c$ to $2T_c$, pointing to stronger interactions at lower temperatures. At the same time, the correlator becomes flatter from $6T_c$ down to $2T_c$, indicating a relative shift of the spectral weight to lower frequencies. A recent next-to-leading order perturbative calculation of the correlator agrees with the time dependence of the lattice data at the few-percent level. We estimate how much additional contribution from the $\\omega\\lesss...

  10. A non-perturbative estimate of the heavy quark momentum diffusion coefficient

    CERN Document Server

    Francis, A; Laine, M; Neuhaus, T; Ohno, H

    2015-01-01

    We estimate the momentum diffusion coefficient of a heavy quark within a pure SU(3) plasma at a temperature of about 1.5Tc. Large-scale Monte Carlo simulations on a series of lattices extending up to 192^3*48 permit us to carry out a continuum extrapolation of the so-called colour-electric imaginary-time correlator. The extrapolated correlator is analyzed with the help of theoretically motivated models for the corresponding spectral function. Evidence for a non-zero transport coefficient is found and, incorporating systematic uncertainties reflecting model assumptions, we obtain kappa = (1.8 - 3.4)T^3. This implies that the "drag coefficient", characterizing the time scale at which heavy quarks adjust to hydrodynamic flow, is (1.8 - 3.4) (Tc/T)^2 (M/1.5GeV) fm/c, where M is the heavy quark kinetic mass. The results apply to bottom and, with somewhat larger systematic uncertainties, to charm quarks.

  11. B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    CERN Document Server

    Christ, Norman H; Izubuchi, Taku; Kawanai, Taichi; Lehner, Christoph; Soni, Amarjit; Van de Water, Ruth S; Witzel, Oliver

    2014-01-01

    We calculate the B-meson decay constants f_B, f_Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ~ 0.11, 0.086 fm with unitary pion masses as light as M_pi ~ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also impr...

  12. Color coherence in a heavy quark antenna radiating gluons inside a QCD medium

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Manoel R. [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain); Institut de Physique Théorique, Saclay (France); Moldes, Manoel R., E-mail: manoel.rodriguez-moldes@usc.es [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain); Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France); Salgado, Carlos A. [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia (Spain)

    2014-11-10

    We compute the color coherence effects for soft gluon radiation off antennas containing heavy quarks in the presence of a QCD medium – the actual calculations is made for a triplet configuration and then generalize to both color singlet and octet ones. This work completes the studies of antenna radiation inside a medium which provide a useful picture of the relevance of interference effects in jet parton showers for the jet quenching phenomenon observed in high-energy nuclear collisions. The analysis is performed resumming the multiple scatterings of the partonic system with the medium. The main conclusion is that decorrelation due to color rotation is more effective in the case in which at least one of the emitters of the antenna is a heavy quark. This effect, present both for a heavy-quark–antiquark or a heavy-quark–gluon antenna is more relevant for the later or for the case in which the energies of the quark and antiquark are very different. The parameter controlling these effects involves the dead-cone angle. We find that interferences are cancelled, spoiling the color correlation of the pair, when θ{sub DC}≡M/E≫1/√(ωL) where E and ω are the energies of the heavy quark and the radiated gluon and L is the medium length. In the case of a heavy-quark–antiquark antenna t{sub form}, defined as the difference in splitting times in amplitude and complex conjugate of the amplitude, appears instead of L if the original splitting is symmetric. The presence or absence of interferences modifies the energy loss pattern.

  13. Color coherence in a heavy quark antenna radiating gluons inside a QCD medium

    Directory of Open Access Journals (Sweden)

    Manoel R. Calvo

    2014-11-01

    Full Text Available We compute the color coherence effects for soft gluon radiation off antennas containing heavy quarks in the presence of a QCD medium – the actual calculations is made for a triplet configuration and then generalize to both color singlet and octet ones. This work completes the studies of antenna radiation inside a medium which provide a useful picture of the relevance of interference effects in jet parton showers for the jet quenching phenomenon observed in high-energy nuclear collisions. The analysis is performed resumming the multiple scatterings of the partonic system with the medium. The main conclusion is that decorrelation due to color rotation is more effective in the case in which at least one of the emitters of the antenna is a heavy quark. This effect, present both for a heavy-quark–antiquark or a heavy-quark–gluon antenna is more relevant for the later or for the case in which the energies of the quark and antiquark are very different. The parameter controlling these effects involves the dead-cone angle. We find that interferences are cancelled, spoiling the color correlation of the pair, when θDC≡M/E≫1/ωL where E and ω are the energies of the heavy quark and the radiated gluon and L is the medium length. In the case of a heavy-quark–antiquark antenna tform, defined as the difference in splitting times in amplitude and complex conjugate of the amplitude, appears instead of L if the original splitting is symmetric. The presence or absence of interferences modifies the energy loss pattern.

  14. Prompt photon in association with a heavy-quark jet in Pb-Pb collisions at the LHC

    CERN Document Server

    Stavreva, T; Schienbein, I

    2012-01-01

    We present a phenomenological study of the associated production of a prompt photon and a heavy quark jet (charm or bottom) in Pb-Pb collisions at the LHC. This channel allows for estimating the amount of energy loss experienced by the charm and bottom quarks propagating in the dense QCD medium produced in those collisions. Calculations are carried out at next-to-leading order (NLO) accuracy using the BDMPS-Z heavy-quark quenching weights. The quenching of the single heavy-quark jet spectrum reflects fairly the hierarchy in the heavy quark energy loss assumed in the perturbative calculation. On the contrary, the single photon spectrum in heavy-ion collisions is only modified at low momenta, for which less heavy-quark jets pass the kinematic cuts. On top of single particle spectra, the two-particle final state provides a range of observables (photon-jet pair momentum, jet asymmetry, among others) which are studied in detail. The comparison of the photon-jet pair momentum, from p-p to Pb-Pb collisions, is sensi...

  15. Strong Decays of Hybrid Mesons from the Heavy Quark Expansion of QCD

    CERN Document Server

    Page, P R

    1998-01-01

    We calculate the strong decays of hybrid mesons to conventional mesons for all the lowest lying J^PC hybrids of flavour uu, dd, ss, cc and bb. A decay operator developed from the heavy quark expansion of quantum chromodynamics is employed. We show that the selection rule that hybrid mesons do not decay to identical S-wave mesons, found in other models, is preserved. We predict decays of charmonium hybrids, discuss decays of J^PC=1^-+ exotic isovector hybrids of various masses, and interpret the \\pi(1800) as a hybrid meson.

  16. Heavy meson spectra for heavy quark potential in quantum chromodynamics with dilaton

    Institute of Scientific and Technical Information of China (English)

    陈洪; 杨兴华; 姜焕清

    2002-01-01

    For heavy meson systems, we study the heavy quark potential, which emerges from the effective dilaton-gluoncoupling inspired from the superstring theory. We put emphasis on the new confinement generating mechanism of thispotential through the investigation of the spin-averaged energy levels of the heavy meson systems. By using a unifiedapproach to the solutions of the Schrodinger and the spinless Salpeter equations, we can examine in a realistic waythe effects of using a relativistic kinetic energy. The obtained results agree favourably with other predictions, and therelativistic equation can better account for the observed energy levels.

  17. Heavy Quark Entropy shift: From the Hadron Resonance Gas to Power Corrections

    CERN Document Server

    Megias, E; Salcedo, L L

    2016-01-01

    A heavy quark placed in the medium modifies its specific heat. Using a renormalization group argument we show a low energy theorem in terms of the defect in the trace of the energy-momentum tensor which allows the unambiguous determination of the corresponding entropy shift after imposing the third principle of thermodynamics for degenerate states. We show how recent lattice QCD data can be understood in the confined phase in terms of a single-heavy hadronic spectrum and above the phase transition through power corrections which are analyzed by means of a dimension 2 gluon condensate of the dimensionally reduced theory.

  18. Mass effects in the emission of gluons from heavy quarks at high energies

    CERN Document Server

    Fuster, J A; Tortosa, P

    2001-01-01

    The effects in the emission of gluons due to the mass of the heavy quarks have clearly been observed by the experiments at LEP and SLC. The analyses of the data using theoretical corrections computed at Next-to-Leading Order have allowed to either test the flavour independence of the strong coupling constant with very high precision (~1%) or measure the b-quark mass at high energy, square root s~M/sub Z/. The results obtained by the various experiments, ALEPH, DELPHI, OPAL and SLD, agree well within errors. The systematic uncertainties limit present determinations though new methods and strategies are being developed to overcome the present bounds. (15 refs).

  19. Asymmetries in Heavy Quark Pair and Dijet Production at an EIC

    CERN Document Server

    Boer, Daniël; Pisano, Cristian; Zhou, Jian

    2016-01-01

    Asymmetries in heavy quark pair and dijet production in electron-proton collisions allow studies of gluon TMDs in close analogy to studies of quark TMDs in semi-inclusive DIS. Here we present expressions for azimuthal asymmetries for both unpolarized and transversely polarized proton cases and consider the maximal asymmetries allowed. The latter are found to be rather sizeable, except in certain kinematic limits which are pointed out. In addition, we consider the small-x limit and expectations from a McLerran-Venugopalan model for unpolarized and linearly polarized gluons and from a perturbative, large transverse momentum calculation for the T-odd gluon TMDs. Comparison to related observables at RHIC and LHC is expected to provide valuable information about the process dependence of the gluon TMDs. In particular this will offer the possibility of a sign change test of the gluon Sivers TMD and two other T-odd gluon TMDs. This provides additional motivation for studies of azimuthal asymmetries in heavy quark pa...

  20. NLO Monte Carlo predictions for heavy-quark production at the LHC. pp collisions in ALICE

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M.; Kovarik, K.; Topp, M. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Klein-Boesing, C. [Muenster Univ. (Germany). Inst. fuer Kernphysik; GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Kramer, G. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Wessels, J.P. [Muenster Univ. (Germany). Inst. fuer Kernphysik

    2014-05-15

    Next-to-leading order (NLO) QCD predictions for the production of heavy quarks in proton-proton collisions are presented within three different approaches to quark mass, resummation and fragmentation effects. In particular, new NLO and parton shower simulations with POWHEG are performed in the ALICE kinematic regime at three different centre-of-mass energies, including scale and parton density variations, in order to establish a reliable baseline for future detailed studies of heavy-quark suppression in heavy-ion collisions. Very good agreement of POWHEG is found with FONLL, in particular for centrally produced D{sup 0}, D{sup +} and D{sup *+} mesons and electrons from charm and bottom quark decays, but also with the generally somewhat higher GM-VFNS predictions within the theoretical uncertainties. The latter are dominated by scale rather than quark mass variations. Parton density uncertainties for charm and bottom quark production are computed here with POWHEG for the first time and shown to be dominant in the forward regime, e.g. for muons coming from heavy-flavour decays. The fragmentation into D{sub s}{sup +} mesons seems to require further tuning within the NLO Monte Carlo approach.

  1. NLO Monte Carlo predictions for heavy-quark production at the LHC: pp collisions in ALICE

    Science.gov (United States)

    Klasen, M.; Klein-Bösing, C.; Kovarik, K.; Kramer, G.; Topp, M.; Wessels, J. P.

    2014-08-01

    Next-to-leading order (NLO) QCD predictions for the production of heavy quarks in proton-proton collisions are presented within three different approaches to quark mass, resummation and fragmentation effects. In particular, new NLO and parton shower simulations with POWHEG are performed in the ALICE kinematic regime at three different centre-of-mass energies, including scale and parton density variations, in order to establish a reliable baseline for future detailed studies of heavy-quark suppression in heavy-ion collisions. Very good agreement of POWHEG is found with FONLL, in particular for centrally produced D 0, D + and D *+ mesons and electrons from charm and bottom quark decays, but also with the generally somewhat higher GM-VFNS predictions within the theoretical uncertainties. The latter are dominated by scale rather than quark mass variations. Parton density uncertainties for charm and bottom quark production are computed here with POWHEG for the first time and shown to be dominant in the forward regime, e.g. for muons coming from heavy-flavour decays. The fragmentation into D s mesons seems to require further tuning within the NLO Monte Carlo approach.

  2. NLO Monte Carlo predictions for heavy-quark production at the LHC: pp collisions in ALICE

    CERN Document Server

    Klasen, M; Kovarik, K; Kramer, G; Topp, M; Wessels, J

    2014-01-01

    Next-to-leading order (NLO) QCD predictions for the production of heavy quarks in proton-proton collisions are presented within three different approaches to quark mass, resummation and fragmentation effects. In particular, new NLO and parton shower simulations with POWHEG are performed in the ALICE kinematic regime at three different centre-of-mass energies, including scale and parton density variations, in order to establish a reliable baseline for future detailed studies of heavy-quark suppression in heavy-ion collisions. Very good agreement of POWHEG is found with FONLL, in particular for centrally produced D^0, D^+ and D^*+ mesons and electrons from charm and bottom quark decays, but also with the generally somewhat higher GM-VFNS predictions within the theoretical uncertainties. The latter are dominated by scale rather than quark mass variations. Parton density uncertainties for charm and bottom quark production are computed here with POWHEG for the first time and shown to be dominant in the forward reg...

  3. Transverse momentum broadening of heavy quark and gluon energy loss in Sakai-Sugimoto model

    CERN Document Server

    Pang, Yi

    2008-01-01

    In this paper, we calculate the transverse momentum diffusion coefficient kappa_T of heavy quark and gluon penetration length in the deconfinement phase of Sakai-Sugimoto model, which is known as a holographic dual of large N_c QCD. We find that for the heavy quark moving through the thermal plasma with a constant velocity v<1, the transverse momentum diffusion coefficient kappa_T is proportional to lamda*gamma^{{1/3}}*T^4/T_d, and the gluon penetration length delta x is proportional to E^{{2/5}}, these results are different from those calculated in N=4 super-Yang-Mills theory, in which kappa_T is proportional to lambda*gamma^{{1/2}}*T^3 and delta x is proportional to E^{{1/3}}, respectively. In the high energy limit, the difference between the two pairs of results should be evident, so we expect that the future LHC experiments can tell us which model is more closely related to the realistic strongly coupled QCD at finite temperature.

  4. Heavy quark and quarkonium production at CERN LEP2: k_T-factorization versus data

    CERN Document Server

    Lipatov, A V

    2004-01-01

    We present calculations of heavy quark and quarkonium production at CERN LEP2 in the k_T-factorization QCD approach. Both direct and resolved photon contribution are taken into account. The conservative error analisys is performed. The unintegrated gluon distribution in the photon is taken from the full CCFM evolution equation. The traditional color-singlet mechanism to describe non-perturbative transition of heavy quark pair into a final quarkonium is used. Our analisys covers polarization properties of heavy quarkonia at moderate and large transverse momenta. We find that the total and differential open charm production cross sections are consistent with the recent experimental data taken by the L3, OPAL and ALEPH collaborations. At the same time the DELPHI data for the inclusive J/Psi production exceed our predictions but experimental uncertainties are too large to claim a significant inconsistency. The bottom production in photon-photon collisions at CERN LEP2 is hard to explain within the k_T-factorizati...

  5. Diffractive dissociation of gluons into heavy quark-antiquark pairs in proton-proton collisions

    CERN Document Server

    Luszczak, Marta; Szczurek, Antoni

    2013-01-01

    We discuss diffractive dissociation of gluons into heavy quark pairs. The particular mechanism is similar to the diffractive dissociation of virtual photons into quarks, which drives diffractive deep inelastic production of charm in the low-mass diffraction, or large $\\beta$-region. There, it can be understood, with some reservations, in terms of a valence heavy quark content of the Pomeron. The amplitude for the $g p \\to Q \\bar Q p$ is derived in the impact parameter and momentum space. The cross section for single diffractive $p p \\to Q \\bar Q p X$ is calculated as a convolution of the elementary cross section and gluon distribution in the proton. Integrated cross section and the differential distributions in e.g. transverse momentum and rapidity of the charm and bottom quark and antiquark, as well as the quark-antiquark invariant mass are calculated for the nominal LHC energy for different unintegrated gluon distributions from the literature. The ratio of the bottom-to-charm cross sections are shown and di...

  6. Evolution of heavy quark distribution function on quark-gluon plasma: Using the Iterative Laplace Transform Method

    Directory of Open Access Journals (Sweden)

    Pari Sharareh Mehrabi

    2016-01-01

    Full Text Available The “Laplace Transform Method” is used to solve the Fokker-Plank equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.

  7. The effect of meson wave function on heavy-quark fragmentation function

    Energy Technology Data Exchange (ETDEWEB)

    Moosavi Nejad, S.M. [Yazd University, Faculty of Physics (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of)

    2016-05-15

    We calculate the process-independent fragmentation functions (FFs) for a heavy quark to fragment into heavy mesons considering the effects of meson wave function. In all previous works, where the FFs of heavy mesons or heavy baryons were calculated, a delta function form was approximated for the wave function of hadrons. Here, for the first time, we consider a typical mesonic wave function which is different from the delta function and is the nonrelativistic limit of the solution of Bethe-Salpeter equation with the QCD kernel. We present our numerical results for the heavy FFs and show how the proposed wave function improves the previous results. As an example, we focus on the fragmentation function for c-quark to split into S-wave D{sup 0} -meson and compare our results with experimental data from BELLE and CLEO. (orig.)

  8. Higher-orders in heavy quark processes within the LTD approach

    CERN Document Server

    Sborlini, German F R

    2016-01-01

    The computation of perturbative corrections to processes involving heavy quarks is crucial for the precision program of the LHC and future colliders. In this article, we describe a powerful approach to calculate higher-orders in QCD skipping the traditional subtraction method. Our proposal is based on the loop-tree duality (LTD) theorem, which allows to rewrite virtual contributions in terms of integrals over the real emission phase-space. Then, we proceed to combine both real and virtual contributions at the integrand level, obtaining regular expressions that can be numerically integrated in four space-time dimensions. In this way, we avoid dealing with complicated massive Feynman integrals and introducing infrared counter-terms. Some reference examples are explained, in order to exhibit the potential of our method.

  9. Heavy quark meson spectroscopy at CDF (X(3872) mass and evidence for Y(4140))

    CERN Document Server

    Wick, Felix

    2010-01-01

    With growing datasets collected by the CDF II experiment, studies of the spectroscopy of mesons containing heavy quarks become more exciting. The CDF experiment has good capabilities in both charm and bottom sector. This capability allowed also to contribute to the study of the zoo of states called X,Y,Z. In this area we present a recent update of the mass measurement of X(3872). The result m(X(3872)) = 3871.61 +- 0.16 +- 0.19 MeV is currently the most precise measurement in the world. In addition, we report evidence for a new narrow resonance, Y(4140), the first to be seen in the J/psi phi decay mode, using 2.7 invfb of exclusive B+ to J/psi phi K+ decays.

  10. NLO QCD Corrections to the Polarized Photo- and Hadroproduction of Heavy Quarks

    CERN Document Server

    Bojak, I

    2000-01-01

    The complete details of our calculation of the NLO QCD corrections to heavy flavor photo- and hadroproduction with longitudinally polarized initial states are presented. The main motivation for investigating these processes is the determination of the polarized gluon density at the COMPASS and RHIC experiments, respectively, in the near future. All methods used in the computation are extensively documented, providing a self-contained introduction to this type of calculations. Some employed tools also may be of general interest, e.g., the series expansion of hypergeometric functions. The relevant parton level results are collected and plotted in the form of scaling functions. However, the simplification of the obtained gluon-gluon virtual contributions has not been completed yet. Thus NLO phenomenological predictions are only given in the case of photoproduction. The theoretical uncertainties of these predictions, in particular with respect to the heavy quark mass, are carefully considered. Also it is shown th...

  11. Non-perturbative QCD: renormalization, O(a)-improvement and matching to Heavy Quark Effective Theory

    CERN Document Server

    Sommer, R

    2006-01-01

    We give an introduction to three topics in lattice gauge theory: I. The Schroedinger Functional and O(a) improvement. O(a) improvement has been reviewed several times. Here we focus on explaining the basic ideas in detail and then proceed directly to an overview of the literature and our personal assessment of what has been achieved and what is missing. II. The computation of the running coupling, running quark masses and the extraction of the renormalization group invariants. We focus on the basic strategy and on the large effort that has been invested in understanding the continuum limit. We point out what remains to be done. III. Non-perturbative Heavy Quark Effective Theory. Since the literature on this subject is still rather sparse, we go beyond the basic ideas and discuss in some detail how the theory works in principle and in practice.

  12. Nonperturbative heavy-quark diffusion in the quark-gluon plasma.

    Science.gov (United States)

    van Hees, H; Mannarelli, M; Greco, V; Rapp, R

    2008-05-16

    We evaluate heavy-quark (HQ) transport properties in a quark-gluon plasma (QGP) within a Brueckner many-body scheme employing interaction potentials extracted from thermal lattice QCD. The in-medium T matrices for elastic charm- and bottom-quark scattering off light quarks in the QGP are dominated by attractive meson and diquark channels which support resonance states up to temperatures of ~1.5T(c). The resulting drag coefficient increases with decreasing temperature, contrary to expectations based on perturbative QCD scattering. Employing relativistic Langevin simulations we compute HQ spectra and elliptic flow in sqrt[s(NN)]=200 GeV Au-Au collisions. A good agreement with electron decay data supports our nonperturbative computation of HQ diffusion, indicative for a strongly coupled QGP.

  13. Effect of temperature gradient on heavy quark anti-quark potential using gravity dual model

    CERN Document Server

    Ganesh, S

    2016-01-01

    The Quark-gluon plasma (QGP) is an expanding fireball, with finite dimensions. Given the finite dimensions, the temperature would be highest at the center, and close to the critical temperature, $T_c$, at the boundary, giving rise to a temperature gradient inside the QGP. A heavy quark anti-quark pair immersed in the QGP medium would see this temperature gradient. The effect of the temperature gradient on the quark anti-quark potential is analyzed using a gravity dual model. The resulting modification to the potential due to the temperature gradient is seen to have a $L^{-2}$ correction term. This could be a possible fallout of the breaking of conformal invariance at finite temperature.

  14. Heavy-quark transport coefficients in a hot viscous quark-gluon plasma medium

    CERN Document Server

    Das, Santosh K; Alam, Jan-e

    2012-01-01

    The heavy-quark (HQ) transport coefficients have been estimated for a viscous quark-gluon plasma medium, utilizing a recently proposed quasi-particle description based on realistic QGP equation of state (EoS). Interactions entering through the equation of state significantly suppress the temperature dependence of the drag coefficient of QGP as compared to that of an ideal system of quarks and gluons. Inclusion of shear and bulk viscosities through the corrections to the thermal phase space factors of the bath particles alters the magnitude of the drag coefficient and the enhancement is significant at lower temperatures. The competition between the effects of realistic EoS and dissipative corrections through phase space factor the former eventually dictate how the drag coefficient would behave as a function of temperature, and how much quantitatively digress from the ideal case. The observations suggest significant impact of both the realistic equation of state, and the viscosities, on the HQs transport at RHI...

  15. Disentangling the timescales behind the non-perturbative heavy quark potential

    CERN Document Server

    Burnier, Yannis

    2012-01-01

    The static part of the heavy quark potential has been shown to be closely related to the spectrum of the rectangular Wilson loop. In particular the lowest lying positive frequency peak encodes the late time evolution of the two-body system, characterized by a complex potential. While initial studies assumed a perfect separation of early and late time physics, where a simple Lorentian (Breit-Wigner) shape suffices to describe the spectral peak, we argue that scale decoupling in general is not complete. Thus early time, i.e. non-potential effects, significantly modify the shape of the lowest peak. We derive on general grounds an improved peak distribution that reflects this fact. Application of the improved fit to non-perturbative lattice QCD spectra now yields a potential that is compatible with a transition to a deconfined screening plasma.

  16. Measurement of the branching ratio of the Z0 into heavy quarks

    CERN Document Server

    Abe, K; Adam, I; Akimoto, H; Aston, D; Baird, K G; Baltay, C; Band, H R; Barklow, T L; Bauer, J M; Bellodi, G; Berger, R; Blaylock, G; Bogart, J R; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Calcaterra, A; Cassell, R; Chou, A; Cohn, H O; Coller, J A; Convery, M R; Cook, V; Cowan, R F; Crawford, G; Damerell, C J S; Daoudi, M; De Groot, N; De Sangro, R; Dong, D N; Doser, Michael; Dubois, R; Erofeeva, I; Eschenburg, V; Etzion, E; Fahey, S; Falciai, D; Fernández, J P; Flood, K; Frey, R; Hart, E L; Hasuko, K; Hertzbach, S S; Huffer, M E; Huynh, X; Iwasaki, M; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Kajikawa, R; Kalelkar, M; Kang, H J; Kofler, R R; Kroeger, R S; Langston, M; Leith, D W G S; Lia, V; Lin, C; Mancinelli, G; Manly, S; Mantovani, G C; Markiewicz, T W; Maruyama, T; McKemey, A K; Messner, R; Moffeit, K C; Moore, T B; Morii, M; Müller, D; Murzin, V; Narita, S; Nauenberg, U; Neal, H; Nesom, G; Oishi, N; Onoprienko, D; Osborne, L S; Panvini, R S; Park, C H; Peruzzi, I; Piccolo, M; Piemontese, L; Plano, R J; Prepost, R; Prescott, C Y; Ratcliff, B N; Reidy, J; Reinertsen, P L; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T; Schumm, B A; Schwiening, J; Serbo, V V; Shapiro, G; Sinev, N B; Snyder, J A; Stängle, H; Stahl, A; Stamer, P; Steiner, H; Su, D; Suekane, F; Sugiyama, A; Suzuki, A; Swartz, M; Taylor, F E; Thom, J; Torrence, E; Usher, T; Vavra, J; Verdier, R; Wagner, D L; Waite, A P; Walston, S; Weidemann, A W; Weiss, E R; Whitaker, J S; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Wittlin, J L; Woods, M; Wright, T R; Yamamoto, R K; Yashima, J; Yellin, S J; Young, C C; Yuta, H

    2005-01-01

    We measure the hadronic branching ratios of the Z0 boson into heavy quarks: Rb=Gamma(Z0->bb)/Gamma(Z0->hadrons) and Rc=Gamma(Z0->cc/Gamma(Z0->hadrons) using a multi-tag technique. The measurement was performed using about 400,000 hadronic Z0 events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct bottom and charm hadron decay vertices with high efficiency and purity, which enables us to measure most efficiencies from data. We obtain, Rb=0.21610 +- 0.00098(stat.) +- 0.00073(syst.) -+ 0.00012(Rc) and, Rc= 0.1745 +- 0.0031(stat.) +- 0.0020(syst.) -+ 0.0006(Rb)

  17. Prompt photon and associated heavy quark production at hadron colliders with kt-factorization

    CERN Document Server

    Lipatov, A V; Zotov, N P

    2012-01-01

    In the framework of the kt-factorization approach, the production of prompt photons in association with a heavy (charm or beauty) quarks at high energies is studied. The consideration is based on the O(\\alpha \\alpha_s^2) off-shell amplitudes of gluon-gluon fusion and quark-(anti)quark interaction subprocesses. The unintegrated parton densities in a proton are determined using the Kimber-Martin-Ryskin prescription. The analysis covers the total and differential cross sections and extends to specific angular correlations between the produced prompt photons and muons originating from the semileptonic decays of associated heavy quarks. Theoretical uncertainties of our evaluations are studied and comparison with the results of standard NLO pQCD calculations is performed. Our numerical predictions are compared with the recent experimental data taken by the D0 and CDF collaborations at the Tevatron. Finally, we extend our results to LHC energies.

  18. How to measure kinetic energy of the heavy quark inside B mesons?

    CERN Document Server

    Bigi, Ikaros I; Shifman, M; Uraltsev, N; Vainshtein, A I

    1994-01-01

    We discuss how one can determine the average kinetic energy of the heavy quark inside heavy mesons from differential distributions in B decays. A new, so-called third, sum rule for the b\\rightarrow c transition is derived in the small velocity (SV) limit. Using this sum rule and the existing data on the momentum dependence in the B\\rightarrow D^* transition (the slope of the Isgur-Wise function) we obtain a new lower bound on the parameter \\mu_\\pi^2 = (2M_B)^{-1}\\langle B |\\bar b (i\\vec{D})^2 b |B\\rangle proportional to the average kinetic energy of b quark inside B meson. The existing data suggest \\mu_\\pi^2 > 0.4~GeV^2 and (from the ``optical'' sum rule) \\overline{\\Lambda} > 500 MeV, albeit with some numerical uncertainties.

  19. Semileptonic bc to cc Baryon Decay and Heavy Quark Spin Symmetry

    CERN Document Server

    Flynn, Jonathan M

    2007-01-01

    We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons (Xi_{bc}^{(\\prime*)}--> Xi_{cc}^{(*)} and Omega_{bc}^{(\\prime*)}--> Omega_{cc}^{(*)}), in the limit m_b, m_c >> Lambda_{QCD} and close to the zero recoil point. The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor. We recover results derived previously by White and Savage in a manner which we think is more straightforward and parallels the method applied later to study Bc semileptonic decays. We further discuss the resemblence between the bc baryon decays and those of Bc mesons to eta_c and J/\\psi mesons and comment on the relation between the slopes of the single functions describing each set of decays. Our results can straightforwardly be applied to the decays of bb baryons to bc baryons.

  20. Heavy Quark Tomography of A+A Including Elastic and Inelastic Energy Loss

    CERN Document Server

    Wicks, S; Gyulassy, M; Horowitz, W; Djordjevic, Magdalena; Gyulassy, Miklos; Horowitz, William; Wicks, Simon

    2005-01-01

    We propose a possible perturbative QCD solution to the heavy quark tomography problem posed by recent non-photonic single electron data from central Au+Au collisions at $\\sqrt{s} = 200$ AGeV. Jet quenching theory is extended to include (1) elastic as well as (2) inelastic parton energy losses and (3) jet path length fluctuations. The three effects combine to reduce the discrepancy between theory and the data without violating the global entropy bounds from multiplicity and elliptic flow data. We also check for consistency with the pion suppression data out to 20 GeV. Fluctuations of the geometric jet path lengths and the difference between the widths of fluctuations of elastic and inelastic energy loss play essential roles in the proposed solution.

  1. Non-perturbative QCD. Renormalization, O(a)-improvement and matching to heavy quark effective theory

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, R.

    2006-11-15

    We give an introduction to three topics in lattice gauge theory: I. The Schroedinger Functional and O(a) improvement. O(a) improvement has been reviewed several times. Here we focus on explaining the basic ideas in detail and then proceed directly to an overview of the literature and our personal assessment of what has been achieved and what is missing. II. The computation of the running coupling, running quark masses and the extraction of the renormalization group invariants. We focus on the basic strategy and on the large effort that has been invested in understanding the continuum limit. We point out what remains to be done. III. Non-perturbative Heavy Quark Effective Theory. Since the literature on this subject is still rather sparse, we go beyond the basic ideas and discuss in some detail how the theory works in principle and in practice. (orig.)

  2. Heavy Quark and Neutrino Physics. Final report, 2011-2-14

    Energy Technology Data Exchange (ETDEWEB)

    Horton-Smith, Glenn A. [Kansas State Univ., Manhattan, KS (United States); Bolton, Timothy [Kansas State Univ., Manhattan, KS (United States); Ivanov, Andrew [Kansas State Univ., Manhattan, KS (United States); Maravin, Yurii [Kansas State Univ., Manhattan, KS (United States); Ratra, Bharat [Kansas State Univ., Manhattan, KS (United States)

    2014-07-21

    This final closeout report covers research supported by the ''Heavy Quark and Neutrino Physics'' grant at Kansas State University during the grant's last renewal period, November 1, 2011, through April 30, 2014. The report begins with an overview of the group, its goals and activities, and personnel. Then summaries are given of achievements in each of the three frontiers: Energy Frontier research in the D0 and CMS experiments; Intensity Frontier research in the Double Chooz and ArgoNeuT experiments as well as research and development for MicroBooNE and LBNE; and Cosmic Frontier and Theoretical research. The report concludes with a list of publications supported by this grant in which our group made a significant contribution during the reporting period, followed by a list of students partially or fully supported by the grant who were awarded a PhD during this period.

  3. Higgs production in heavy-quark annihilation through next-to-next-to-leading order QCD

    Energy Technology Data Exchange (ETDEWEB)

    Harlander, Robert V. [RWTH Aachen University, Institute for Theoretical Particle Physics and Cosmology, Aachen (Germany)

    2016-05-15

    The total inclusive cross section for charged and neutral Higgs production in heavy-quark annihilation is presented through NNLO QCD. It is shown that, aside from an overall factor, the partonic cross section is independent of the initial-state quark flavors, and that any interference terms involving two different Yukawa couplings vanish. A simple criterion for defining the central renormalization and factorization scale is proposed. Its application to the b anti bφ process yields results which are compatible with the values usually adopted for this process. Remarkably, we find little variation in these values for the other initial-state quark flavors. Finally, we disentangle the impact of the different parton luminosities from genuine hard NNLO effects and find that, for the central scales, a naive rescaling by the parton luminosities approximates the full result remarkably well. (orig.)

  4. Perturbative aspects of the phase diagram of QCD with heavy quarks

    Science.gov (United States)

    Serreau, Julien; Reinosa, Urko

    2017-03-01

    We report on recent progress in the description of the phase diagram of QCD with heavy quarks at nonzero temperature and chemical potential in the context of a modified perturbative approach. The latter is based on a simple massive extension of the QCD Lagrangian in the Landau-DeWitt gauge, the background field generalization of the Landau gauge. Here, the background field plays the role of an order parameter for the center symmetry, relevant for confinement-deconfinement transition. One-loop results in this approach give a fairly accurate description of the phase diagram both at real and imaginary chemical potential. We comment on issues related to the sign problem in continuum approaches. Based on works in collaboration with Matthieu Tissier and Nicolás Wschebor.

  5. Heavy quark fragmentation functions at next-to-leading perturbative QCD

    CERN Document Server

    Nejad, S M Moosavi

    2016-01-01

    It is well-known that the dominant mechanism to produce hadronic bound states with large transverse momentum is fragmentation. This mechanism is described by the fragmentation functions (FFs) which are the universal and process-independent functions. Here, we review the perturbative FFs formalism as an appropriate tool for studying these hadronization processes and detail the extension of this formalism at next-to-leading order (NLO). Using the Suzuki's model, we calculate the perturbative QCD FF for a heavy quark to fragment into a S-wave heavy meson at NLO. As an example, we study the LO and NLO FFs for a charm quark to split into the S-wave $D$-meson and compare our analytic results both with experimental data and well-known phenomenological models.

  6. New results on CLEO`s heavy quarks - bottom and charm

    Energy Technology Data Exchange (ETDEWEB)

    Menary, S. [Univ. of California, Santa Barbara, CA (United States)

    1997-01-01

    While the top quark is confined to virtual reality for CLEO, the increased luminosity of the Cornell Electron Storage Ring (CESR) and the improved photon detection capabilities of the CLEO`s {open_quotes}heavy{close_quotes} quarks - bottom and charm. I will describe new results in the B meson sector including the first observation of exclusive b {yields} ulv decays, upper limits on gluonic penguin decay rates, and precise measurements of semileptonic and hadronic b {yields} c branching fractions. The charmed hadron results that are discussed include the observation of isospin violation in D{sub s}*{sup +} decays, an update on measurements of the D{sub s}{sup +} decay constant, and the observation of a new excited {Xi}{sub c} charmed baryon. These measurements have had a large impact on our understanding of heavy quark physics.

  7. Heavy-quark fragmentation functions at next-to-leading perturbative QCD

    Energy Technology Data Exchange (ETDEWEB)

    Moosavi Nejad, S.M. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of); Sartipi Yarahmadi, P. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of)

    2016-10-15

    It is well known that the dominant mechanism to produce hadronic bound states with large transverse momentum is fragmentation. This mechanism is described by the fragmentation functions (FFs) which are the universal and process-independent functions. Here, we review the perturbative FFs formalism as an appropriate tool for studying these hadronization processes and detail the extension of this formalism at next-to-leading order (NLO). Using Suzuki's model, we calculate the perturbative QCD FF for a heavy quark to fragment into a S-wave heavy meson at NLO. As an example, we study the LO and NLO FFs for a charm quark to split into the S-wave D-meson and compare our analytic results both with experimental data and well-known phenomenological models. (orig.)

  8. Measurements of $Z^{0}$ to Heavy-quark couplings at SLD

    CERN Document Server

    Iwasaki, M

    1999-01-01

    We present measurements of $Z^0$ to heavy-quark coupling electroweak parameters, $R_b$, $R_c$, and parity-violation parameter $A_c$, from SLD. The measurements are based on approximately 550k hadronic $Z^0$ events collected in 1993-98. Obtained preliminary results of $R_b$ and $R_c$ measurements are $R_b = 0.2159 \\pm 0.0014 \\pm 0.0014$ and $R_c = 0.1685 \\pm 0.0047 \\pm 0.0043$. In the $A_c$ measurement, we use four methods to determine the initial-quark charge: combined Kaon charge and Vertex charge, lepton, exclusively reconstructed D*, D-mesons, and a new method using inclusive soft-pion from D*. The preliminary results of these four methods were combined to give $A_c = 0.634 \\pm 0.027$.

  9. The Bayesian reconstruction of the in-medium heavy quark potential from lattice QCD and its stability

    Energy Technology Data Exchange (ETDEWEB)

    Burnier, Yannis [Institut de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland); Kaczmarek, Olaf [Fakultät für Physik, Universität Bielefeld, D-33615 Bielefeld (Germany); Rothkopf, Alexander [Institute for Theoretical Physics, Heidelberg University, Philosophenweg 16, D-69120 Heidelberg (Germany)

    2016-01-22

    We report recent results of a non-perturbative determination of the static heavy-quark potential in quenched and dynamical lattice QCD at finite temperature. The real and imaginary part of this complex quantity are extracted from the spectral function of Wilson line correlators in Coulomb gauge. To obtain spectral information from Euclidean time numerical data, our study relies on a novel Bayesian prescription that differs from the Maximum Entropy Method. We perform simulations on quenched 32{sup 3} × N{sub τ} (β = 7.0, ξ = 3.5) lattices with N{sub τ} = 24, …, 96, which cover 839MeV ≥ T ≥ 210MeV. To investigate the potential in a quark-gluon plasma with light u,d and s quarks we utilize N{sub f} = 2 + 1 ASQTAD lattices with m{sub l} = m{sub s}/20 by the HotQCD collaboration, giving access to temperatures between 286MeV ≥ T ≥ 148MeV. The real part of the potential exhibits a clean transition from a linear, confining behavior in the hadronic phase to a Debye screened form above deconfinement. Interestingly its values lie close to the color singlet free energies in Coulomb gauge at all temperatures. We estimate the imaginary part on quenched lattices and find that it is of the same order of magnitude as in hard-thermal loop perturbation theory. From among all the systematic checks carried out in our study, we discuss explicitly the dependence of the result on the default model and the number of datapoints.

  10. Phenomenology of renormalons and the OPE from lattice regularization: The gluon condensate and the heavy quark pole mass

    Energy Technology Data Exchange (ETDEWEB)

    Bali, Gunnar S. [Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg (Germany); Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Pineda, Antonio [Grup de Física Teòrica and IFAE, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona (Spain)

    2016-01-22

    We study the operator product expansion of the plaquette (gluon condensate) and the self-energy of an infinitely heavy quark. We first compute their perturbative expansions to order α{sup 35} and α{sup 20}, respectively, in the lattice scheme. In both cases we reach the asymptotic regime where the renormalon behavior sets in. Subtracting the perturbative series, we obtain the leading non-perturbative corrections of their respective operator product expansions. In the first case we obtain the gluon condensate and in the second the binding energy of the heavy quark in the infinite mass limit. The results are fully consistent with the expectations from renormalons and the operator product expansion.

  11. From perturbative calculations of the QCD static potential towards four-loop pole-running heavy quarks masses relation

    CERN Document Server

    Kataev, A L

    2016-01-01

    The summary of the available semi-analytical results for the three-loop corrections to the QCD static potential and for the $\\mathcal{O}(\\alpha_s^4)$ contributions to the ratio of the running and pole heavy quark masses are presented. The procedure of the determination of the dependence of the four-loop contribution to the pole-running heavy quarks mass ratio on the number of quarks flavours, based on application of the least squares method is described. The necessity of clarifying the reason of discrepancy between the numerical uncertainties of the $\\alpha_s^4$ coefficients in the mass ratio, obtained by this mathematical method by the direct numerical calculations is emphasised.

  12. Search for new heavy quarks in proton-antiproton collisions at radical s=0. 63 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Albajar, C.; Albrow, M.G.; Allkofer, O.C.; Andrieu, B.; Ankoviak, K.; Apsimon, R.; Aubert, B.; Bacci, C.; Bartha, S.; Bauer, G.; Beingessner, S.; Bettini, A.; Bezaguet, A.; Biddulph, P.; Bohn, H.; Boehrer, A.; Bonino, R.; Bos, K.; Botlo, M.; Brockhausen, D.; Buchanan, C.; Buschbeck, B.; Busetto, G.; Caner, A.; Casoli, P.; Castilla-Valdez, H.; Cavanna, F.; Cennini, P.; Centro, S.; Ceradini, F.; Ciapetti, G.; Cittolin, S.; Clayton, E.; Cline, D.; Colas, J.; Conte, R.; Coughlan, J.A.; Cox, G.; Dau, D.; Daum, C.; DeGiorgi, M.; Della Negra, M.; Demoulin, M.; Denegri, D.; Dibon, H.; DiCiaccio, A.; Diez Hedo, F.J.; Dobrzynski, L.; Dorenbosch, J.; Dowell, J.D.; Drijard, D.; Eggert, K.; Eisenhandler, E.; Ellis, N.; Erhard, P.; Evans, H.; Faissner, H.; Felcini, M.; Fensome, I.F.; Ferrando, A.; Fortson, L.; Fuess, T.; Garvey, J.; Geiser, A.; Givernaud, A.; Gonidec, A.; Gonzalez, B.; Gregory, J.M.; Gronberg, J.; Holthuizen, D.J.; Jank, W.; Jimack, M.; Jorat, G.; Josa, M.I.; Kalmus, P.I.P.; Karimae; UA1 Collaboration

    1990-09-01

    We report on a search for new heavy quarks decaying semileptonically into muons, using 4.7 pb{sup -1} of data taken during the CERN panti p collider runs in 1988 and 1989. The properties of isolated muons accompanied by jets are consistent with the predictions from the Standard Model but do not show a signal for a new heavy quark. Combining all the UA1 data (5.4 pb{sup -1}), lower mass limits are obtained at 60 GeV/c{sup 2} (95% CL) for the t-quark and 43 GeV/c{sup 2} (95% CL) for a fourth-generation charge-1/3 quark (b'-quark). (orig.).

  13. Towards next-to-leading order corrections to the heavy quark potential in the effective string theory

    Science.gov (United States)

    Hwang, Sungmin

    2017-03-01

    We present our calculation of the non-relativistic corrections to the heavy quark-antiquark potential up to leading and next-to-leading order (NLO) via the effective string theory (EST). Full systematics of effective field theory (EFT) are discussed in order for including the NLO contribution that arises in the EST. We also show how the number of dimensionful parameters arising from the EST are reduced by the constraints between the Wilson coeffcients from non-relativistic EFTs for QCD.

  14. Search for New Physics Processes with Heavy Quark Signatures in the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00388427

    A program involving searches for new physics with heavy quark final states using data from the ATLAS experiment at the LHC is presented here. The signal and expected backgrounds for the decay $B_{s}→μ^{+} μ^{-} μ^{+} μ^{-}$, a rare decay whose branching ratio may be enhanced by the presence of certain Beyond the Standard Model processes, are studied, and the groundwork is laid for a future analysis. Possible mediators include horizontal gauge bosons, supersymmetry via sgoldstinos, and interactions with the hidden sector. To this end, a set of twelve triggers have been selected and studied, and their efficiency figures of merit have been calculated. A truth trigger efficiency study was performed in order to determine if new triggers should be installed for the analysis. The backgrounds have been studied, and a mass window technique was used to reduce their amplitude relative to the signal. A proposal to improve the efficiency of some of the ATLAS High-Level B-physics Triggers, based on refining the selec...

  15. Exotic baryons as a hadronic molecule in the heavy quark region

    Directory of Open Access Journals (Sweden)

    Yamaguchi Yasuhiro

    2016-01-01

    Full Text Available We study the hadronic molecules formed by the coupled-channel system of D̄(*Λc and D̄(*Σc(*, inspired by the two hidden-charm pentaquark states observed by LHCb collaborations in 2015. In these molecules, the coupled channels of D̄(*Σc(* are important because the thresholds of these channels are approximately degenerated by the heavy quark spin symmetry. In addition, we consider the coupling to the D̄(*Λc channel whose thresholds are close to the D̄(*Σc(* thresholds, and the coupling to the state with ℓ ≠ 0 mixed by the tensor force. By solving the coupled-channel Schrödinger equations with the one meson exchange potentials, we study the hidden-charm hadronic molecules with I(JP = 1/2(3/2± and 1/2(5/2±. We conclude that the JP assignment of the observed pentaquarks is 3/2+ for P+c (4380 and 5/2− for P+c (4450, which is agreement with the results of the LHCb analysis. In addition, we give predictions for other JP = 3/2± states.

  16. Parton distribution functions, αs, and heavy-quark masses for LHC Run II

    Science.gov (United States)

    Alekhin, S.; Blümlein, J.; Moch, S.; PlačakytÄ--, R.

    2017-07-01

    We determine a new set of parton distribution functions (ABMP16), the strong coupling constant αs and the quark masses mc, mb and mt in a global fit to next-to-next-to-leading order (NNLO) in QCD. The analysis uses the MS ¯ scheme for αs and all quark masses and is performed in the fixed-flavor number scheme for nf=3 , 4, 5. Essential new elements of the fit are the combined data from HERA for inclusive deep-inelastic scattering (DIS), data from the fixed-target experiments NOMAD and CHORUS for neutrino-induced DIS, data from Tevatron and the LHC for the Drell-Yan process and the hadro-production of single-top and top-quark pairs. The theory predictions include new improved approximations at NNLO for the production of heavy quarks in DIS and for the hadro-production of single-top quarks. The description of higher twist effects relevant beyond the leading twist collinear factorization approximation is refined. At NNLO, we obtain the value αs(nf=5 )(MZ)=0.1147 ±0.0008 .

  17. Search for Pair Produced Heavy Quarks Decaying into a Z Boson and a Light Generation Jet

    CERN Document Server

    AUTHOR|(SzGeCERN)672562

    We present here our results from the search for the pair production of new massive quarks using $20\\ifb$ data collected by the ATLAS detector in 2012 proton-proton collisions at $\\rts=$8TeV centre of mass energy. There are many models extending beyond the well established Standard Model (SM) predicting additional massive quarks on top of the existing quark list. One of them is the grand unified theory (GUT) having the exceptional $E_{6}$ as its symmetry group. This model predicts an additional iso-singlet down type quark for each existing SM family with possible decay channels involving $\\Wpm,\\Zboson$ and $H$. Assuming a similar mass structure, the lightest of these quarks denoted by the letter $D$ would be the first one to be discovered at ATLAS. Our search focuses on the decay signature of $D$ quark decays via a $\\Zboson$ boson which would further decay into two leptons. The other heavy quark searches at ATLAS are carried out with the assumption that the new quarks should couple to the heavy generations $t$...

  18. Gauge bosons and heavy quarks: Proceedings of Summer Institute on Particle Physics

    Science.gov (United States)

    Hawthorne, J. F.

    1991-01-01

    This report contains papers on the following topics: Z decays and tests of the standard model; future possibilities for LEP; studies of the interactions of electroweak gauge bosons; top quark topics; the next linear collider; electroweak processes in hadron colliders; theoretical topics in B-physics; experimental aspects of B-physics; B-factory storage ring design; rare kaon decays; CP violation in K(sup 0) decays at CERN; recent K(sup 0) decay results from Fermilab E-731; results from LEP on heavy quark physics; review of recent results on heavy flavor production; weak matrix elements and the determination of the weak mixing angles; recent results from CLEO I and a glance at CLEO II data; recent results from ARGUS; neutrino lepton physics with the CHARM 2 detector; recent results from the three TRISTAN experiments; baryon number violation at high energy in the standard model: fact or fiction? New particle searches at LEP; review of QCD at LEP; electroweak interactions at LEP; recent results on W physics from the UA2 experiment at the CERN rho(bar rho) collider; B physics at CDF; and review of particle astrophysics.

  19. Heavy-Quark Associated Production with One Hard Photon at Hadron Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Hartanto, Heribertus Bayu [Florida State Univ., Tallahassee, FL (United States)

    2013-01-01

    We present the calculation of heavy-quark associated production with a hard photon at hadron colliders, namely $pp(p\\bar p) → Q\\bar Q +X$γ (for $Q=t,b$), at Next-to-Leading Order (NLO) in Quantum Chromodynamics (QCD). We study the impact of NLO QCD corrections on the total cross section and several differential distributions at both the Tevatron and the Large Hadron Collider (LHC). For $t\\bar t$γ production we observe a sizeable reduction of the renormalization and factorization scale dependence when the NLO QCD corrections are included, while for $b\\bar b$γ production a considerable scale dependence still persists at NLO in QCD. This is consistent with what emerges in similar processes involving $b$ quarks and vector bosons and we explain its origin in detail. For $b\\bar b$γ production we study both the case in which at least one $b$ jet and the case in which at least two $b$ jets are observed. We perform the $b\\bar b$γ calculation using the Four Flavor Number Scheme (4FNS) and compare the case where at least one $b$ jet is observed with the corresponding results from the Five Flavor Number Scheme (5FNS) calculation. Finally we compare our results for $p\\bar p →+b+X$γ with the Tevatron data.

  20. Heavy-quark transport coefficients in a hot viscous quark-gluon plasma medium

    Science.gov (United States)

    Das, Santosh K.; Chandra, Vinod; Alam, Jan-e.

    2014-01-01

    Heavy-quark (HQ) transport coefficients have been estimated for a viscous quark-gluon plasma (QGP) medium, utilizing a recently proposed quasi-particle description based on a realistic QGP equation of state (EoS). Interactions entering through the EoS significantly suppress the temperature dependence of the drag coefficient of QGP, compared to those of an ideal relativistic system of quarks and gluons. The inclusion of shear and bulk viscosities through the corrections to the thermal phase space factors of the bath particles alters the magnitude of the drag coefficient; the enhancement is significant at lower temperatures. In the competition between the effects of the EoS and dissipative corrections through phase space factors, the former eventually dictate how the drag coefficient would behave as a function of temperature and how much it quantitatively digresses from the ideal case. The observations suggest a significant impact of both the realistic EoS and the viscosities on the HQs transport at Relativistic Heavy Ion Collider and Large Hadron Collider collision energies.

  1. 3-Loop Heavy Flavor Corrections in Deep-Inelastic Scattering with Two Heavy Quark Lines

    CERN Document Server

    Ablinger, J; De Freitas, A; Hasselhuhn, A; von Manteuffel, A; Round, M; Schneider, C; Wißbrock, F

    2014-01-01

    We consider gluonic contributions to the heavy flavor Wilson coefficients at 3-loop order in QCD with two heavy quark lines in the asymptotic region $Q^2 \\gg m_{1(2)}^2$. Here we report on the complete result in the case of two equal masses $m_1 = m_2$ for the massive operator matrix element $A_{gg,Q}^{(3)}$, which contributes to the corresponding heavy flavor transition matrix element in the variable flavor number scheme. Nested finite binomial sums and iterated integrals over square-root valued alphabets emerge in the result for this quantity in $N$ and $x$-space, respectively. We also present results for the case of two unequal masses for the flavor non-singlet OMEs and on the scalar integrals ic case of $A_{gg,Q}^{(3)}$, which were calculated without a further approximation. The graphs can be expressed by finite nested binomial sums over generalized harmonic sums, the alphabet of which contains rational letters in the ratio $\\eta = m_1^2/m_2^2$.

  2. Charmonium-Nucleon Interaction from Quenched Lattice QCD with Relativistic Heavy Quark Action

    Science.gov (United States)

    Kawanai, Taichi; Sasaki, Shoichi; Hatsuda, Tetsuo

    2009-10-01

    Low energy charmonium-nucleon interaction is of particular interest in this talk. A heavy quarkonium state like the charmonium does not share the same quark flavor with the nucleon so that cc-nucleon interaction might be described by the gluonic van der Waals interaction, which is weak but attractive. Therefore, the information of the strength of cc-nucleon interaction is vital for considering the possibility of the formation of charmonium bound to nuclei. We will present the preliminary results for the scattering length and the interaction range of charmonium-nucleon s-wave scattering from quenched lattice QCD. These low-energy quantities can provide useful constraints on the phenomenological cc-nucleon potential, which is required for precise prediction of the binding energy of nuclear-bound charmonium in exact few body calculations. Our simulations are performed at a lattice cutoff of 1/a=2.0 GeV with the nonperturbatively O(a) improved Wilson action for the light quark and a relativistic heavy quark action for the charm quark. A new attempt of calculating the cc-nucleon potential through the Bethe-Salpeter wave function will be also discussed.

  3. Complex heavy-quark potential and Debye mass in a gluonic medium from lattice QCD

    CERN Document Server

    Burnier, Yannis

    2016-01-01

    We improve and extend our study of the complex in-medium heavy quark potential and its Debye mass $m_D$ in a gluonic medium with a finer scan around the deconfinement transition and newly generated ensembles closer to the thermodynamic limit. On the lattices with larger physical volume, Re[V] shows signs of screening, i.e. a finite $m_D$, only in the deconfined phase, reminiscent of a genuine phase transition. Consistently Im[V] exhibits nonzero values also only above $T_C$. We compare the behavior of Re[V] with the color singlet free-energies that have been used historically to extract the Debye mass. An effective coupling constant is computed to assess the residual influence of the confining part of the potential at $T>0$. Our previous finding of a gradual screening of Re[V] around $T_C$ on finer lattices is critically reassessed and interpreted to originate from finite volume artifacts that affect the deployed $\\beta=7$, $\\xi_b=3.5$ parameter set at $N_s=32$.

  4. Heavy Quark Diffusion in Strong Magnetic Fields at Weak Coupling and Implication to Elliptic Flow

    CERN Document Server

    Fukushima, Kenji; Yee, Ho-Ung; Yin, Yi

    2015-01-01

    We compute the momentum diffusion coefficients of heavy quarks, $\\kappa_\\parallel$ and $\\kappa_\\perp$, in a strong magnetic field $B$ along the directions parallel and perpendicular to $B$, respectively, at the leading order in QCD coupling constant $\\alpha_s$. We consider a regime relevant for the relativistic heavy ion collisions, $\\alpha_s eB\\ll T^2\\ll eB$, so that thermal excitations of light quarks are restricted to the lowest Landau level (LLL) states. In the vanishing light-quark mass limit, we find $\\kappa_\\perp^{\\rm LO}\\propto \\alpha_s^2 T eB$ in the leading order that arises from screened Coulomb scatterings with (1+1)-dimensional LLL quarks, while $\\kappa_\\parallel$ gets no contribution from the scatterings with LLL quarks due to kinematic restrictions. We show that the first non-zero leading order contributions to $\\kappa_\\parallel^{\\rm LO}$ come from the two separate effects: 1) the screened Coulomb scatterings with thermal gluons, and 2) a finite light-quark mass $m_q$. The former leads to $\\kap...

  5. Drag and Diffusion of Heavy Quarks in a hot and anisotropic QCD medium

    CERN Document Server

    Srivastava, P K

    2016-01-01

    The propagation of heavy quarks (HQs) in a medium was quite often modeled by the Fokker-Plank (FP) equation. Since the transport coefficients, related to drag and diffusion processes are the main ingredients in the FP equation, the evolution of HQs is thus effectively controlled by them. At the initial stage of the relativistic heavy ion collisions, asymptotic weak-coupling causes the free-streaming motions of partons in the beam direction and the expansion in transverse directions are almost frozen, hence an anisotropy in the momentum space sets in. Since HQs are too produced in the same time therefore the study of the effect of momentum anisotropy on the drag and diffusion coefficients becomes advertently desirable. In this article we have thus studied the drag and diffusion of HQs in the anisotropic medium and found that the presence of the anisotropy reduces both drag and diffusion coefficients. In addition, the anisotropy introduces an angular dependence to both the drag and diffusion coefficients, as a ...

  6. Density of Saturated Nuclear Matter at Large $N_{c}$ and Heavy Quark Mass Limits

    CERN Document Server

    Adhikari, Prabal; Datta, Ishaun

    2013-01-01

    We exhibit the existence of stable, saturated nuclear matter in the large $N_{c}$ and heavy quark mass limits of QCD. In this limit, baryons (with the same spin flavor structure) interact at leading order in $N_{c}$ via a repulsive interaction due to the Pauli exclusion principle and at subleading order in $1/N_c$ via the exchange of glueballs. Assuming that the lightest glueball is a scalar, which implies that the subleading baryon interaction is attractive, we find that nuclear matter saturates since the subleading attractive interaction is longer ranged than the leading order repulsive one. We find that the saturated matter is in the form of a crystal with either a face-centered cubic or a hexagonal-close-packed symmetry with baryon densities of $\\mathcal{O}((\\, \\tilde{\\alpha}_{s} m_q (\\ln (N_{c}m_{q}\\Lambda_{\\textrm{QCD}}^{-1}))^{-1})^3 )$. Remarkably, the leading order expression for the density of saturated nuclear matter is independent of the lighest glueball mass and scalar-glueball-baryon coupling in...

  7. Heavy-Quark Symmetry and the Electromagnetic Decays of Excited Charmed Strange Mesons

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Mehen; Roxanne P. Springer

    2004-10-01

    Heavy-hadron chiral perturbation theory (HH{chi}PT) is applied to the decays of the even-parity charmed strange mesons, D{sub s0}(2317) and D{sub s1}(2460). Heavy-quark spin symmetry predicts the branching fractions for the three electromagnetic decays of these states to the ground states D{sub s} and D{sub s}* in terms of a single parameter. The resulting predictions for two of the branching fractions are significantly higher than current upper limits from the CLEO experiment. Leading corrections to the branching ratios from chiral loop diagrams and spin-symmetry violating operators in the HH{chi}PT Lagrangian can naturally account for this discrepancy. Finally the proposal that the D{sub s0}(2317) (D{sub s1}(2460)) is a hadronic bound state of a D (D*) meson and a kaon is considered. Leading order predictions for electromagnetic branching ratios in this molecular scenario are in very poor agreement with existing data.

  8. A gauge invariant Debye mass for the complex heavy-quark potential

    CERN Document Server

    Burnier, Yannis

    2016-01-01

    The concept of a screening mass is a powerful tool to simplify the intricate physics of in-medium test charges surrounded by light charge carriers. While it has been successfully used to describe electromagnetic properties, its definition and computation in QCD is plagued by questions of gauge invariance and the presence of non-perturbative contributions from the magnetic sector. Here we present a recent alternative definition of a gauge invariant Debye mass parameter following closely the original idea of Debye and Hueckel. Our test charges are a static heavy quark-antiquark pair whose complex potential and its in-medium modification can be extracted using lattice QCD. By combining in a generalized Gauss-Law the non-perturbative aspects of quark binding with a perturbative ansatz for the medium effects, we succeed to describe the lattice values of the potential with a single temperature dependent parameter, in turn identified with a Debye mass. We find that its behavior, as evaluated in a recent quenched lat...

  9. 3-Loop Heavy Flavor Corrections in Deep-Inelastic Scattering with Two Heavy Quark Lines

    Science.gov (United States)

    Ablinger, J.; Bluemlein, J.; de Freitas, A.; Hasselhuhn, A.; von Manteuffel, A.; Round, M.; Schneider, C.; Wissbrock, F.

    We consider gluonic contributions to the heavy flavor Wilson coefficients at 3-loop order in QCD with two heavy quark lines in the asymptotic region $Q^2 \\gg m_{1(2)}^2$. Here we report on the complete result in the case of two equal masses $m_1 = m_2$ for the massive operator matrix element $A_{gg,Q}^{(3)}$, which contributes to the corresponding heavy flavor transition matrix element in the variable flavor number scheme. Nested finite binomial sums and iterated integrals over square-root valued alphabets emerge in the result for this quantity in $N$ and $x$-space, respectively. We also present results for the case of two unequal masses for the flavor non-singlet OMEs and on the scalar integrals ic case of $A_{gg,Q}^{(3)}$, which were calculated without a further approximation. The graphs can be expressed by finite nested binomial sums over generalized harmonic sums, the alphabet of which contains rational letters in the ratio $\\eta = m_1^2/m_2^2$.

  10. 3-loop heavy flavor corrections in deep-inelastic scattering with two heavy quark lines

    Energy Technology Data Exchange (ETDEWEB)

    Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Bluemlein, J.; Freitas, A. de [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hasselhuhn, A.; Round, M. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Manteuffel, A. von [Mainz Univ. (Germany). Inst. fuer Physik; Wissbrock, F. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Institut des Hautes Etudes Scientifiques, Bures-sur-Yvette (France)

    2014-07-15

    We consider gluonic contributions to the heavy flavor Wilson coefficients at 3-loop order in QCD with two heavy quark lines in the asymptotic region Q{sup 2} >> m{sup 2}{sub 1(2)}. Here we report on the complete result in the case of two equal masses m{sub 1}=m{sub 2} for the massive operator matrix element A{sup (3)}{sub gg,Q}, which contributes to the corresponding heavy flavor transition matrix element in the variable flavor number scheme. Nested finite binomial sums and iterated integrals over square-root valued alphabets emerge in the result for this quantity in N and x-space, respectively. We also present results for the case of two unequal masses for the flavor non-singlet OMEs and on the scalar integrals ic case of A{sup (3)}{sub gg,Q}, which were calculated without a further approximation. The graphs can be expressed by finite nested binomial sums over generalized harmonic sums, the alphabet of which contains rational letters in the ratio η=m{sup 2}{sub 1}/m{sup 2}{sub 2}.

  11. Partners of the X(3872) and heavy quark spin symmetry breaking

    Science.gov (United States)

    Entem, D. R.; Ortega, P. G.; Fernández, F.

    2016-05-01

    Since the discovery of the X(3872) the study of heavy meson molecules has been the subject of many investigations. Different experiments have looked for its spin partners and the bottom analogs. On the theoretical side different approaches have been used to understand this state. Some of them as Effective Field Theories (EFT) that impose Heavy Quark Spin Symmetry (HQSS) and so they make predictions for the partners of the X(3872), suggesting the existence of a JPC = 2++ partner in the charm sector or JPC = 1++ or 2++ analogs in the bottom sector. In this work, in order to understand the X(3872), we use a Chiral Quark Model in which, due to the proximity to the DD* threshold, we include cc ¯ states coupled to meson-antimeson DD* molecular components. In this coupled channel model the relative position of the bare cc ¯ states with two meson thresholds are very important. We have looked for the X(3872) partners and we do not find a bound state in the D* D* JPC = 2++. In the bottom sector we find the opposite situation where the B* B* with JPC = 2++ is bounded while the JPC = 1++ is not. These results show how the coupling with cc ¯ states can induce different results than those expected by HQSS. The reason is that this symmetry is worse in the open heavy meson sector than in the hidden heavy meson sector.

  12. Gauge bosons and heavy quarks: Proceedings of Summer Institute on Particle Physics

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, J.F. (ed.)

    1991-01-01

    This report contains papers on the following topics: Z decays and tests of the standard model; future possibilities for LEP; studies of the interactions of electroweak gauge bosons; top quark topics; the next linear collider; electroweak processes in hadron colliders; theoretical topics in B-physics; experimental aspects of B-physics; B-factory storage ring design; rare kaon decays; CP violation in K{sup 0} decays at CERN; recent K{sup 0} decay results from Fermilab E-731; results from LEP on heavy quark physics; review of recent results on heavy flavor production; weak matrix elements and the determination of the weak mixing angles; recent results from CLEO I and a glance at CLEO II data; recent results from ARGUS; neutrino lepton physics with the CHARM 2 detector; recent results from the three TRISTAN experiments; baryon number violation at high energy in the standard model: fact or fiction New particle searches at LEP; review of QCD at LEP; electroweak interactions at LEP; recent results on W physics from the UA2 experiment at the CERN {rho}{bar {rho}} collider; B physics at CDF; and review of particle astrophysics.

  13. Heavy-Quark Meson Spectrum Tests of the Oktay-Kronfeld Action

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Jon A. [Seoul Natl. U., Dept. Phys. Astron.; Jang, Yong-Chull [Seoul Natl. U., Dept. Phys. Astron.; Lee, Weonjong [Seoul Natl. U., Dept. Phys. Astron.; DeTar, Carleton [Utah U.; Kronfeld, Andreas S. [Fermilab; Oktay, Mehmet B. [Utah U.

    2017-01-02

    The Oktay-Kronfeld (OK) action extends the Fermilab improvement program for massive Wilson fermions to higher order in suitable power-counting schemes. It includes dimension-six and -seven operators necessary for matching to QCD through order ${\\mathrm{O}}(\\Lambda^3/m_Q^3)$ in HQET power counting, for applications to heavy-light systems, and ${\\mathrm{O}}(v^6)$ in NRQCD power counting, for applications to quarkonia. In the Symanzik power counting of lattice gauge theory near the continuum limit, the OK action includes all ${\\mathrm{O}}(a^2)$ and some ${\\mathrm{O}}(a^3)$ terms. To assess whether the theoretical improvement is realized in practice, we study combinations of heavy-strange and quarkonia masses and mass splittings, designed to isolate heavy-quark discretization effects. We find that, with one exception, the results obtained with the tree-level-matched OK action are significantly closer to the continuum limit than the results obtained with the Fermilab action. The exception is the hyperfine splitting of the bottom-strange system, for which our statistical errors are too large to draw a firm conclusion. These studies are carried out with data generated with the tadpole-improved Fermilab and OK actions on 500 gauge configurations from one of MILC's $a\\approx0.12$~fm, $N_f=2+1$-flavor, asqtad-staggered ensembles.

  14. Recombination Dynamics in Quantum Well Semiconductor Structures

    Science.gov (United States)

    Fouquet, Julie Elizabeth

    Time-resolved and time-integrated photoluminescence as a function of excitation energy density have been observed in order to study recombination dynamics in GaAs/Al(,x)Ga(,1 -x)As quantum well structures. The study of room temperature photoluminescence from the molecular beam epitaxy (MBE) -grown multiple quantum well structure and photoluminescence peak energy as a function of tem- perature shows that room temperature recombination at excitation densities above the low 10('16) cm('-3) level is due to free carriers, not excitons. This is the first study of time-resolved photoluminescence of impurities in quantum wells; data taken at different emission wave- lengths at low temperatures shows that the impurity-related states at photon energies lower than the free exciton peaks luminesce much more slowly than the free exciton states. Results from a similar structure grown by metal -organic chemical vapor deposition (MOCVD) are explained by saturation of traps. An unusual increase in decay rate observed tens of nanoseconds after excitation is probably due to carriers falling out of the trap states. Since this is the first study of time-resolved photoluminescence of MOCVD-grown quantum well structures, this unusual behavior may be realted to the MOCVD growth process. Further investigations indi- cate that the traps are not active at low temperatures; they become active at approximately 150 K. The traps are probably associated with the (hetero)interfaces rather than the bulk Al(,x)Ga(,1-x)As material. The 34 K photoluminescence spectrum of this sample revealed a peak shifted down by approximately 36 meV from the main peak. Time-resolved and time-integrated photoluminescence results here show that this peak is not a stimulated phonon emission sideband, but rather is an due to an acceptor impurity, probably carbon. Photo- luminescence for excitation above and below the barrier bandgap shows that carriers are efficiently collected in the wells in both single and multiple

  15. Challenges to quantum chromodynamics: Anomalous spin, heavy quark, and nuclear phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1989-11-01

    The general structure of QCD meshes remarkably well with the facts of the hadronic world, especially quark-based spectroscopy, current algebra, the approximate point-like structure of large momentum transfer inclusive reactions, and the logarithmic violation of scale invariance in deep inelastic lepton-hadron reactions. QCD has been successful in predicting the features of electron-positron and photon-photon annihilation into hadrons, including the magnitude and scaling of the cross sections, the shape of the photon structure function, the production of hadronic jets with patterns conforming to elementary quark and gluon subprocesses. The experimental measurements appear to be consistent with basic postulates of QCD, that the charge and weak currents within hadrons are carried by fractionally-charged quarks, and that the strength of the interactions between the quarks, and gluons becomes weak at short distances, consistent with asymptotic freedom. Nevertheless in some cases, the predictions of QCD appear to be in dramatic conflict with experiment. The anomalies suggest that the proton itself as a much more complex object than suggested by simple non-relativistic quark models. Recent analyses of the proton distribution amplitude using QCD sum rules points to highly-nontrival proton structure. Solutions to QCD in one-space and one-time dimension suggest that the momentum distributions of non-valence quarks in the hadrons have a non-trival oscillatory structure. The data seems also to be suggesting that the intrinsic'' bound state structure of the proton has a non- negligible strange and charm quark content, in addition to the extrinsic'' sources of heavy quarks created in the collision itself. 144 refs., 46 figs., 2 tabs.

  16. Heavy Quark Production in p+p and Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at sqrt(s_NN)=200 GeV

    OpenAIRE

    Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Alexander, J.; Al-Jamel, A.; Aoki, K.; Aphecetche, L.; Armendariz, R. (R.); Aronson, S H; Asai, J.; Atomssa, E. T.; Averbeck, R.

    2010-01-01

    Transverse momentum (p^e_T) spectra of electrons from semileptonic weak decays of heavy flavor mesons in the range of 0.3 < p^e_T < 9.0 GeV/c have been measured at mid-rapidity (|eta| < 0.35) by the PHENIX experiment at the Relativistic Heavy Ion Collider in p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. The nuclear modification factor R_AA with respect to p+p collisions indicates substantial energy loss of heavy quarks in the produced medium. In addition, the azimuthal anisotropy parameter ...

  17. B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Christ, Norman H. [Columbia Univ., New York, NY (United States); Flynn, Jonathan M. [Univ. of Southampton, Southampton (United Kingdom); Izubuchi, Taku [Brookhaven National Lab. (BNL), Upton, NY (United States); Kawanai, Taichi [RIKEN, Wako (Japan); Brookhaven National Lab. (BNL), Upton, NY (United States); Lehner, Christoph [Brookhaven National Lab. (BNL), Upton, NY (United States); Soni, Amarjit [Brookhaven National Lab. (BNL), Upton, NY (United States); Van de Water, Ruth S. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Witzel, Oliver [Boston Univ., Boston, MA (United States)

    2015-03-10

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as Mπ ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(αsa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain fB0 = 196.2(15.7) MeV, fB+ = 195.4(15.8) MeV, fBs = 235.4(12.2) MeV, fBs/fB0 = 1.193(59), and fBs/fB+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.

  18. Towards next-to-leading order corrections to the heavy quark potential in the effective string theory

    Directory of Open Access Journals (Sweden)

    Hwang Sungmin

    2017-01-01

    Full Text Available We present our calculation of the non-relativistic corrections to the heavy quark-antiquark potential up to leading and next-to-leading order (NLO via the effective string theory (EST. Full systematics of effective field theory (EFT are discussed in order for including the NLO contribution that arises in the EST. We also show how the number of dimensionful parameters arising from the EST are reduced by the constraints between the Wilson coeffcients from non-relativistic EFTs for QCD.

  19. Search for pair-produced heavy quarks decaying to Wq in the two-lepton channel at $\\sqrt{s}$ = 7 TeV with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Aderholz, Michael; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Å kesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Akiyama, Kunihiro; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Aliyev, Magsud; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral, Pedro; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amorós, Gabriel; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Å sman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Astvatsatourov, Anatoli; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Ay, Cano; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barashkou, Andrei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Ben Ami, Sagi; Benary, Odette; Benchekroun, Driss; Benchouk, Chafik; Bendel, Markus; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertinelli, Francesco; Bertolucci, Federico; Besana, Maria Ilaria; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bitenc, Urban; Black, Kevin; Blair, Robert

    2012-01-01

    A search is presented for heavy-quark pair production (QQbar) under the decay hypothesis QQbar to WqWq with q = u,d,c,s,b. The search is performed with 1.04 fb^-1 of integrated luminosity from pp collisions at sqrt(s) = 7 TeV collected by the ATLAS detector at the CERN LHC. Dilepton final states are selected, requiring large missing transverse momentum and at least two jets. Mass reconstruction of heavy quark candidates is performed by assuming that the W boson decay products are nearly collinear. The data are in agreement with Standard Model expectations; a heavy quark with mass less than 350 GeV is excluded at 95% confidence level.

  20. Free Energy of a Heavy Quark-Antiquark Pair in a Thermal Medium from AdS/CFT

    CERN Document Server

    Ewerz, Carlo; Samberg, Andreas

    2016-01-01

    We study the free energy of a heavy quark-antiquark pair in a thermal medium using the AdS/CFT correspondence. We point out that a commonly used prescription for calculating this quantity leads to a temperature dependence in conflict with general properties of the free energy. The problem originates from a particular way of subtracting divergences. We argue that the commonly used prescription gives rise to the binding energy rather than the free energy. We consider a different subtraction procedure and show that the resulting free energy is well-behaved and in qualitative agreement with results from lattice QCD. The free energy and the binding energy of the quark pair are computed for N = 4 supersymmetric Yang-Mills theory and several non-conformal theories. We also calculate the entropy and the internal energy of the pair in these theories. Using the consistent subtraction, we further study the free energy, entropy, and internal energy of a single heavy quark in the thermal medium for various theories. Also ...

  1. Searches for exotic heavy quarks decaying into a W-Boson and a b-Quark with the ATLAS experiment

    CERN Document Server

    Nektarijevic, Snezana

    In this thesis, searches for two hypothetical heavy quarks are presented: the fourth Standard Model generation up-type quark t’, and the vector-like quark T, predicted by the new physics models involving extra dimensions or a composite Higgs boson. Both searches assume pair production of the heavy quarks decaying to a W-boson and a b-quark, and are performed in final states with one electron or muon, at least three jets, and significant missing transverse energy. The first search employs the kinematic fitting of the reconstructed quark mass, while the second relies on the artificial neural network method. In both searches no excess of data over the Standard Model expectation is observed, resulting in observed lower bounds on the quark masses of mt’>404 GeV and mT>618 GeV. Both searches are based on proton-proton collision data at 7 TeV centre-of-mass energy collected by the ATLAS experiment at CERN’s Large Hadron Collider in 2011.

  2. Near Zone Navier-Stokes Analysis of Heavy Quark Jet Quenching in an $\\mathcal{N}$ =4 SYM Plasma

    CERN Document Server

    Noronha, Jorge; Gyulassy, Miklos

    2007-01-01

    The near zone energy-momentum tensor of a supersonic heavy quark jet moving through a strongly-coupled $\\mathcal{N}=4$ SYM plasma is analyzed in terms of nonlinear Navier-Stokes hydrodynamics. We show that local isotropic equilibrium in the Landau frame holds to within 20% accuracy down to a length scale $\\sim 1/\\pi T$, much smaller than found previously from far zone analysis. For distances less than this scale, the AdS solution rapidly becomes non-isotropic and local equilibrium breaks down. The component of the dissipative stress also remain small compared to the advective (non-viscous) fluid stress down to distances $\\sim 1/\\pi T$ from the heavy quark jet. Our result, which is compatible with the thermalization timescales extracted from elliptic flow measurements, suggests that if AdS/CFT provides a good description of the RHIC system, the bulk of the quenched jet energy has more than enough time to locally thermalize and become encoded in the collective flow. The resulting flow pattern close to the quark...

  3. Charge carrier recombination dynamics in perovskite and polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Paulke, Andreas; Kniepert, Juliane; Kurpiers, Jona; Wolff, Christian M.; Schön, Natalie; Brenner, Thomas J. K.; Neher, Dieter [Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24–25, 14476, Potsdam (Germany); Stranks, Samuel D. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Snaith, Henry J. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2016-03-14

    Time-delayed collection field experiments are applied to planar organometal halide perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) based solar cells to investigate charge carrier recombination in a fully working solar cell at the nanosecond to microsecond time scale. Recombination of mobile (extractable) charges is shown to follow second-order recombination dynamics for all fluences and time scales tested. Most importantly, the bimolecular recombination coefficient is found to be time-dependent, with an initial value of ca. 10{sup −9} cm{sup 3}/s and a progressive reduction within the first tens of nanoseconds. Comparison to the prototypical organic bulk heterojunction device PTB7:PC{sub 71}BM yields important differences with regard to the mechanism and time scale of free carrier recombination.

  4. Dynamics of carrier recombination in a semiconductor laser structure

    Energy Technology Data Exchange (ETDEWEB)

    Dzhioev, R. I., E-mail: dzhioev@orient.ioffe.ru; Kavokin, K. V.; Kusrayev, Yu. G.; Poletaev, N. K. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2015-11-15

    Carrier-recombination dynamics is studied by the method of optical orientation at room temperature in the active layer of a laser diode structure. The dependence of the degree of electron-spin orientation on the excitation density is attributed to saturation of the nonradiative-recombination channel. The time of electron capture at recombination centers is determined to be τ{sub e} = 5 × 10{sup –9} s. The temperature of nonequilibrium electrons heated by a He–Ne laser is estimated.

  5. Peculiar features of the relations between pole and running heavy quark masses and estimates of the O(\\alpha_s^4) contributions

    CERN Document Server

    Kataev, A L

    2010-01-01

    Perturbative relations between pole and running heavy quark masses, defined in the Minkowski regions, are considered. Special attention is paid to the appearance of the kinematic $\\pi^2$-effects, which exist in the coefficients of these series. The estimates of order $O(\\alpha_s^4)$ QCD corrections are presented.

  6. The b-quark mass from non-perturbative $N_f=2$ Heavy Quark Effective Theory at $O(1/m_h)$

    DEFF Research Database (Denmark)

    Bernardoni, F.; Blossier, B.; Bulava, J.

    2014-01-01

    We report our final estimate of the b-quark mass from $N_f=2$ lattice QCD simulations using Heavy Quark Effective Theory non-perturbatively matched to QCD at $O(1/m_h)$. Treating systematic and statistical errors in a conservative manner, we obtain $\\overline{m}_{\\rm b}^{\\overline{\\rm MS}}(2 {\\rm...

  7. Dynamical evolution, hadronization and angular de-correlation of heavy flavor in a hot and dense QCD medium

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shanshan [Department of Physics, Duke University, Durham, NC 27708 (United States); Qin, Guang-You [Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, Wuhan 430079 (China); Bass, Steffen A. [Department of Physics, Duke University, Durham, NC 27708 (United States)

    2014-12-15

    We study heavy flavor evolution and hadronization in relativistic heavy-ion collisions. The in-medium evolution of heavy quarks is described using our modified Langevin framework that incorporates both collisional and radiative energy loss mechanisms. The subsequent hadronization process for heavy quarks is calculated with a fragmentation plus recombination model. We find significant contribution from gluon radiation to heavy quark energy loss at high p{sub T}; the recombination mechanism can greatly enhance the D meson production at medium p{sub T}. Our calculation provides a good description of the D meson nuclear modification at the LHC. In addition, we explore the angular correlation functions of heavy flavor pairs which may provide us a potential candidate for distinguishing different energy loss mechanisms of heavy quarks inside the QGP.

  8. Two-loop planar master integrals for Higgs$\\to 3$ partons with full heavy-quark mass dependence

    CERN Document Server

    Bonciani, Roberto; Frellesvig, Hjalte; Henn, Johannes M; Moriello, Francesco; Smirnov, Vladimir A

    2016-01-01

    We present the analytic computation of all the planar master integrals which contribute to the two-loop scattering amplitudes for Higgs$\\to 3$ partons, with full heavy-quark mass dependence. These are relevant for the NNLO corrections to fully inclusive Higgs production and to the NLO corrections to Higgs production in association with a jet, in the full theory. The computation is performed using the differential equations method. Whenever possible, a basis of master integrals that are pure functions of uniform weight is used. The result is expressed in terms of one-fold integrals of polylogarithms and elementary functions up to transcendental weight four. Two integral sectors are expressed in terms of elliptic functions. We show that by introducing a one-dimensional parametrization of the integrals the relevant second order differential equation can be readily solved, and the solution can be expressed to all orders of the dimensional regularization parameter in terms of iterated integrals over elliptic kerne...

  9. Constraining in-medium heavy-quark energy-loss mechanisms via angular correlations between heavy and light mesons

    Science.gov (United States)

    Rohrmoser, M.; Gossiaux, P.-B.; Gousset, T.; Aichelin, J.

    2017-01-01

    Two-particle correlations obtained from parton showers that pass the hot and dense medium of the quark gluon plasma (QGP) can be used as an alternative observable, in addition to the combination of the nuclear modification factor RAA and the elliptic flow v 2, to study the mechanisms of in-medium heavy quark energy-loss. In particular, angular correlations represent a promising tool to distinguish between energy loss due to collisional and radiative interactions of jet and medium particles. To this end, parton cascades were created in Monte-Carlo simulations, where individual particles can undergo both parton splitting as well as an effective jet-medium interaction. A first model simulates the effects of induced radiations on parton cascades. Its consequences on angular correlations of partons within jets were studied in detail, with particular focus on angular broadening. The results can be compared to a second model that effectively describes elastic scatterings of jet and medium particles.

  10. Constraining in-medium heavy-quark energy-loss mechanisms via angular correlations between heavy and light mesons

    CERN Document Server

    Rohrmoser, Martin; Gousset, Thierry; Aichelin, Jörg

    2016-01-01

    Two-particle correlations obtained from parton showers that pass the hot and dense medium of the quark gluon plasma (QGP) can be used as an alternative observable, in addition to the combination of the nuclear modification factor $R_{AA}$ and the elliptic flow $v_2$, to study the mechanisms of in-medium heavy quark energy-loss. In particular, angular correlations represent a promising tool to distinguish between energy loss due to collisional and radiative interactions of jet and medium particles. To this end, parton cascades were created in Monte-Carlo simulations, where individual particles can undergo both parton splitting as well as an effective jet-medium interaction. A first model simulates the effects of induced radiations on parton cascades. Its consequences on angular correlations of partons within jets were studied in detail, with particular focus on angular broadening. The results can be compared to a second model that effectively describes elastic scatterings of jet and medium particles.

  11. Heavy-quark contributions to the ratio F{sub L}/F{sub 2} at low x

    Energy Technology Data Exchange (ETDEWEB)

    Illarinov, A.Y. [Scuola Internazionale Superiore di Studi Avanzati, Trieste (Italy); Kniehl, B.A.; Kotikov, A.V. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2008-01-15

    We study the heavy-quark contribution to the proton structure functions F{sup i}{sub 2}(x,Q{sup 2}) and F{sup i}{sub L} (x,Q{sup 2}), with i=c,b, for small values of Bjorken's x variable at next-to-lading order and provide compact formulas for their ratios R{sub i} = F{sup i}{sub L} /F{sup i}{sub 2} that are useful to extract F{sup i}{sub 2}(x,Q{sup 2}) from measurements of the doubly differential cross section of inclusive deep-inelastic scattering at DESY HERA. Our approach naturally explains why R{sub i} is approximately independent of x and the details of the parton distributions in the small-x regime. (orig.)

  12. A Linearized Boltzmann transport model for jet propagation in the quark-gluon plasma: Heavy quark evolution

    CERN Document Server

    Cao, Shanshan; Qin, Guang-You; Wang, Xin-Nian

    2016-01-01

    A Linearized Boltzmann Transport (LBT) model coupled with hydrodynamical background is established to describe the evolution of jet shower partons and medium excitations in high energy heavy-ion collisions. We extend the LBT model to include both elastic and inelastic processes for light and heavy partons in the quark-gluon plasma. A hybrid model of fragmentation and coalescence is developed for the hadronization of heavy quarks. Within this framework, we investigate how heavy flavor observables depend on various ingredients, such as different energy loss and hadronization mechanisms, the momentum and temperature dependences of the transport coefficients, and the radial flow of the expanding fireball. Our model calculations show good descriptions of $D$ meson suppression and elliptic flow observed at the LHC and RHIC. The prediction for the Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}}$=5.02 TeV is provided.

  13. F-wave heavy-light meson spectroscopy in QCD sum rules and heavy quark effective theory

    CERN Document Server

    Zhou, Dan; Geng, Li-Sheng; Liu, Xiang; Zhu, Shi-Lin

    2015-01-01

    We study the F-wave c_bar s heavy meson doublets (2+,3+) and (3+,4+). They have large orbital excitations L=3, and may be good challenges (tests) for theoretical studies. To study them we use the method of QCD sum rule in the framework of heavy quark effective theory. Their masses are predicted to be m_{(2+,3+)} = (3.45 \\pm 0.25, 3.50 \\pm 0.26) GeV and m_{(3+,4+)} = (3.20 \\pm 0.22, 3.26 \\pm 0.23) GeV, with mass splittings Delta m_{(2+,3+)} = m_{3+} - m_{2+} = 0.046 \\pm 0.030 GeV and Delta m_{(3+,4+)} = 0.053 \\pm 0.044 GeV, respectively.

  14. Nuclear Modification of Electron Spectra and Implications for Heavy Quark Energy Loss in Au+Au Collisions at sqrt(s_NN)=200 GeV

    CERN Document Server

    Adler, S S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, Alberto; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Yu A; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S R; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Büsching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; D'Enterria, D G; Dávid, G; Delagrange, H; Denisov, A; Deshpande, Abhay A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; Du Rietz, R; Durum, A; Dutta, D; Efremenko, Yu V; Egdemir, J; El-Chenawi, K F; Enokizono, A; Enyo, H; Esumi, S; Ewell, L A; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Zeev; Frantz, J E; Franz, A; Frawley, A D; Fung, S Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse-Perdekamp, M; Guryn, W; Gustafsson, Hans Åke; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G B; Kim, H J; Kistenev, E P; Kiyomichi, A; Kiyoyama, K; Klein-Bösing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V P; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A G; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Man'ko, V I; Mao, Y; Martínez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E A; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Muhlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V A; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saitô, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sørensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarjan, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, Itzhak; Tsuruoka, H; Tuli, S K; Tydesjo, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszpremi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E A; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2006-01-01

    The PHENIX experiment has measured mid-rapidity transverse momentum spectra (0.4 < p_T < 5.0 GeV/c) of electrons as a function of centrality in Au+Au collisions at sqrt(s_NN)=200 GeV. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of pi^0 and eta mesons, were removed. The resulting non-photonic electron spectra are primarily due to the semi-leptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to non-photonic electrons in p+p collisions. A significant suppression of electrons at high p_T is observed in central Au+Au collisions, indicating substantial energy loss of heavy quarks.

  15. Fits to Moment Measurements from B->Xc lv and B-> Xs gamma Decays using Heavy Quark Expansions in the Kinetic Scheme

    CERN Document Server

    Buchmüller, O L; Buchmueller, Oliver; Flaecher, Henning

    2006-01-01

    We present a fit to moment measurements of inclusive distributions in B->Xc lv and B->Xs gamma decays to extract values for the CKM matrix element |Vcb|, the b- and c- quark masses, and higher order parameters that appear in the Heavy Quark Expansion. The fit is carried out using theoretical calculations in the kinetic scheme and includes moment measurements of the BaBar, Belle, CDF, CLEO and DELPHI collaborations where correlation matrices have been published. We also derive values for the heavy quark distribution function parameters $m_b$ and $\\mu_{\\pi}^2$ in different theoretical schemes that can be used as input for the evaluation of the associated theory error on |Vub|.

  16. Heavy-quark pair production in polarized photon-photon collisions at next-to-leading order. Fully integrated total cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Kniehl, B.A.; Kotikov, A.V.; Merebashvili, Z.V.; Veretin, O.L. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2009-05-15

    We consider the production of heavy-quark pairs in the collisions of polarized and unpolarized on-shell photons and present, in analytic form, the fully integrated total cross sections for total photon spins J{sub z}=0,{+-}2 at next-to-leading-order in QCD. Phenomenological applications include b anti b production, which represents an irreducible background to standard-model intermediate-mass Higgs-boson production, as well as t anti t production. (orig.)

  17. Proton to pion ratio at RHIC from dynamical quark recombination

    CERN Document Server

    Ayala, Alejandro; Paic, Guy; Toledo-Sanchez, Genaro

    2008-01-01

    We propose an scenario to study, from a dynamical point of view, the thermal recombination of quarks in the midsts of a relativistic heavy-ion collision. We coin the term dynamical quark recombination to refer to the process of quark-antiquark and three-quark clustering, to form mesons and baryons, respectively, as a function of energy density. Using the string-flip model we show that the probabilities to form such clusters differ. We apply these ideas to the calculation of the proton and pion spectra in a Bjorken-like scenario that incorporates the evolution of these probabilities with proper time and compute the proton to pion ratio, comparing to recent RHIC data at the highest energy. We show that for a standard choice of parameters, this ratio reaches one, though the maximum is very sensitive to the initial evolution proper time.

  18. Baryons and Low-Density Baryonic Matter in 1+1 Dimensional Large N_c QCD with Heavy Quarks

    CERN Document Server

    Adhikari, Prabal; Jamgochian, Arec; Kumar, Nilay

    2012-01-01

    This paper studies baryons and baryonic matter in the combined large N_c and heavy quark mass limits of QCD in 1+1 dimension. In this non-relativistic limit, baryons are composed of N_c quarks that interact, at leading order in N_c, through a color Coulomb potential. Using variational techniques, very accurate calculations of single baryon masses and interaction energies of low-density baryon crystal are performed. These results are used to cross-check a general numerical approach applicable for arbitrary quark masses and baryon densities recently proposed by Bringoltz, which is based on a lattice in a finite box with periodic boundary conditions. The Bringoltz method differs from a previous approach of Salcedo, et al. in its treatment of a finite box effect - namely gauge configurations that wind around the box. One might expect these effects to be small for large enough boxes, in which the baryon density approaches zero to high accuracy at the edges. However, the effects of these windings appear to be quite...

  19. Heavy Quark Production in CC and NC DIS and The Structure of Real and Virtual Photons in NLO QCD

    CERN Document Server

    Schienbein, I

    2001-01-01

    This thesis consists of two parts. In the first part heavy quark production in neutral current and charged current DIS is studied within the variable flavor number scheme of Aivazis, Collins, Olness, and Tung (ACOT). For this purpose all the relevant partonic subprocesses have been calculated to order O(\\alpha_s^1) for general masses and couplings taking into account massive initial state quark-partons as needed in the variable flavor number scheme of ACOT. By the calculation of the before missing radiative corrections to scattering amplitudes on massive quark partons the ACOT scheme could be completed to full order O(\\alpha_s^1). These results might also prove useful for studying the intrinsic charm content of nucleons. In the second part the parton content of pions and real and virtual photons is analyzed in leading order (LO) and next-to-leading oder (NLO) QCD within the framework of the radiative parton model of Gl\\"uck, Reya, and Vogt (GRV). Furthermore, the factorization of the cross section for the pro...

  20. Heavy quark symmetry and weak decays of the $b$-baryons in pentaquarks with a $c\\bar{c}$ component

    CERN Document Server

    Ali, Ahmed; Aslam, M Jamil; Rehman, Abdur

    2016-01-01

    The discovery of the baryonic states $P_c^+(4380)$ and $P_c^+(4450)$ by the LHCb collaboration has evoked a lot of theoretical interest. These states have the minimal quark content $c \\bar{c} u u d$. Interpreted as hidden charm diquark-diquark-antiquark baryons, the assigned spin and angular momentum quantum numbers are $P_c^+(4380)= \\{\\bar{c} [cu]_{s=1} [ud]_{s=1}; L_{\\mathcal{P}}=0, J^{\\rm P}=\\frac{3}{2}^- \\}$ and $P_c^+(4450)= \\{\\bar{c} [cu]_{s=1} [ud]_{s=0}; L_{\\mathcal{P}}=1, J^{\\rm P}=\\frac{5}{2}^+ \\}$, where $s=0,1$ are the spins of the diquarks and $L_{\\mathcal{P}}=0,1$ are the orbital angular momentum quantum numbers of the pentaquarks. We point out that heavy quark symmetry allows only the higher mass pentaquark state $P_c^+(4450)$ having $[ud]_{s=0}$ to be produced in $\\Lambda_b^0$ decays, whereas the lower mass state $P_c^+(4380)$ having $[ud]_{s=1}$ is disfavored. Pentaquark spectrum is rich enough to accommodate a $J^P=\\frac{3}{2}^-$ state, which has the correct light diquark spin $\\{\\bar{c} [cu...

  1. Heavy-quark state production in A-A collisions at $\\sqrt{s}$=200 GeV

    CERN Document Server

    Kisslinger, Leonard S; McGaughey, Patrick

    2013-01-01

    We estimate differential rapidity cross sections for $J/\\Psi$ and $\\Upsilon(1S)$ production via Cu-Cu and Au-Au collisions at RHIC, and the relative probabilities of $\\Psi'(2S)$ to $J/\\Psi$ production via p-p collisions using our recent theory of mixed heavy quark hybrids, in which the $\\Psi'(2S)$ mesons have approximately equal normal $q\\bar{q}$ and hybrid $q\\bar{q}g$ components. We also estimate the relative probabilities of $\\Psi'(2S)$ to $J/\\Psi$ production via Cu-Cu and Au-Au collisions, which will be measured in future RHIC experiments. We also review production ratios of $\\Upsilon(2S)$ and $\\Upsilon(3S)$ to $\\Upsilon(1S)$ in comparison to recent experimental results.This is an extension of our recent work on p-p collisions for possible tests of the production of Quark-Gluon Plasma via A-A collisions at BNL-RHIC.

  2. Heavy quark and quarkonium production at CERN LEP2. k{sub T}-factorization versus data

    Energy Technology Data Exchange (ETDEWEB)

    Lipatov, A.V.; Zotov, N.P. [Moskovskij Gosudarstvennyj Univ., Moscow (Russian Federation). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki

    2005-02-01

    We present calculations of heavy quark and quarkonium production at CERN LEP2 in the {kappa}{sub T}-factorization QCD approach. Both direct and resolved photon contribution are taken into account. The conservative error analysis is performed. The unintegrated gluon distribution in the photon is obtained from the full CCFM evolution equation. The traditional color-singlet mechanism to describe non-perturbative transition of QQ-pair into a final quarkonium is used. Our analysis covers polarization properties of heavy quarkonia at moderate and large transverse momenta. We find that the total and differential open charm production cross sections are consistent with the recent experimental data taken by the L3, OPAL and ALEPH collaborations. At the same time the DELPHI data for the inclusive J/{psi} production exceed our predictions but experimental uncertainties are too large to claim a significant inconsistency. The bottom production in photon-photon collisions at CERN LEP2 is hard to explain within the {kappa}{sub T}-factorization formalism. (orig.)

  3. Heavy quark and quarkonium production at CERN LEP2: k{sub T}-factorization versus data

    Energy Technology Data Exchange (ETDEWEB)

    Lipatov, A.V.; Zotov, N.P. [M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation)

    2005-05-01

    We present calculations of heavy quark and quarkonium production at CERN LEP2 in the k{sub T}-factorization QCD approach. Both direct and resolved photon contributions are taken into account. A conservative error analysis is performed. The unintegrated gluon distribution in the photon is obtained from the full CCFM evolution equation. The traditional color-singlet mechanism to describe the non-perturbative transition of a Q anti Q -pair into a final quarkonium is used. Our analysis covers the polarization properties of heavy quarkonia at moderate and large transverse momenta. We find that the total and differential open charm production cross sections are consistent with the recent experimental data taken by the L3, OPAL and ALEPH collaborations. At the same time the DELPHI data for the inclusive J/{psi} production exceed our predictions, but experimental uncertainties are too large to claim a significant inconsistency. The bottom production in photon-photon collisions at CERN LEP2 is hard to explain within the k{sub T}-factorization formalism. (orig.)

  4. Heavy quark symmetry and weak decays of the b baryons in pentaquarks with a c c xAF component

    Science.gov (United States)

    Ali, Ahmed; Ahmed, Ishtiaq; Aslam, M. Jamil; Rehman, Abdur

    2016-09-01

    The discovery of the baryonic states Pc+(4380 ) and Pc+(4450 ) by the LHCb collaboration in the process p p →b b ¯→Λb0X , followed by the decay Λb0→J /ψ p K- has evoked a lot of theoretical interest. These states have the minimal quark content c c ¯u u d , as suggested by their discovery mode J /ψ p , and the preferred JP assignments are 5/2+ for the Pc+(4450 ) and 3/2- for the Pc+(4380 ). In the compact pentaquark hypothesis, in which they are interpreted as hidden charm diquark-diquark-antiquark baryons, the assigned spin and angular momentum quantum numbers are Pc+(4380 )={c ¯ [c u ]s =1[u d ]s =1;LP=0 ,JP=3/2-} and Pc+(4450 )={c ¯[c u ]s=1[u d ]s=0;LP=1 ,JP=5/2+}. The subscripts denote the spin of the diquarks and LP=0 , 1 are the orbital angular momentum quantum numbers of the pentaquarks. We point out that in the heavy quark limit, the spin of the light diquark in heavy baryons becomes a good quantum number, which has consequences for the decay Λb0→J /ψ p K-. With the quantum numbers assigned above for the two pentaquarks, this would allow only the higher mass pentaquark state Pc+(4450 ) having [u d ]s=0 to be produced in Λb0 decays, whereas the lower mass state Pc+(4380 ) having [u d ]s=1 is disfavored, requiring a different interpretation. Pentaquark spectrum is rich enough to accommodate a JP=3/2- state, which has the correct light diquark spin {c ¯[c u ]s=1[u d ]s=0;LP=0 ,JP=3/2-} to be produced in Λb0 decays. Assuming that the mass difference between the charmed pentaquarks which differ in the orbital angular momentum L by one unit is similar to the corresponding mass difference in the charmed baryons, m [Λc+(2625 );JP=3/2-]-m [Λc+(2286 );JP=1/2+]≃341 MeV , we estimate the mass of the lower pentaquark JP=3 /2- state to be about 4110 MeV and suggest to reanalyze the LHCb data to search for this third state. Extending these considerations to the pentaquark states having a c c ¯ pair and three light quarks (u , d , s ) in their

  5. Heavy quark symmetry and weak decays of the b-baryons in pentaquarks with a c anti c component

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmed [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ahmed, Ishtiaq; Rehman, Abdur [Quaid-i-Azam Univ., Islamabad (Pakistan). National Centre for Physics; Aslam, M. Jamil [Quaid-i-Azam Univ., Islamabad (Pakistan). Physics Dept.

    2016-06-15

    The discovery of the baryonic states P{sup +}{sub c}(4380) and P{sup +}{sub c}(4450) by the LHCb collaboration in the process pp→b anti b→Λ{sup 0}{sub b}X, followed by the decay Λ{sup 0}{sub b}→J/ψpK{sup -} has evoked a lot of theoretical interest. These states have the minimal quark content c anti cuud, as suggested by their discovery mode J/ψ p, and the preferred J{sup P} assignments are (5)/(2){sup +} for the P{sup +}{sub c}(4450) and (3)/(2){sup -} for the P{sup +}{sub c}(4380). In the compact pentaquark hypothesis, in which they are interpreted as hidden charm diquark-diquark-antiquark baryons, the assigned spin and angular momentum quantum numbers are P{sup +}{sub c}(4380)={ anti c[cu]_s_=_1[ud]_s_=_1; L_P=0, J"P=(3)/(2)"-} and P{sup +}{sub c}(4450)={ anti c[cu]_s_=_1[ud]_s_=_0; L_P=1, J"P=(5)/(2)"+}. The subscripts denote the spin of the diquarks and L{sub P}=0,1 are the orbital angular momentum quantum numbers of the pentaquarks. We point out that heavy quark limit, the spin of the light diquark in heavy baryons becomes a good quantum number, which has consequences for the decay Λ{sup 0}{sub b}→J/ψpK{sup -}. With the quantum numbers assigned above for the two pentaquarks, this would allow only the higher mass pentaquark state P{sup +}{sub c}(4450) having [ud]{sub s=0} to be produced in Λ{sup 0}{sub b} decays, whereas the lower mass state P{sup +}{sub c}(4380) having [ud]{sub s=1} is disfavored, requiring a different interpretation. Pentaquark spectrum is rich enough to accommodate a J{sup P}=(3)/(2){sup -} state, which has the correct light diquark spin { anti c[cu]_s_=_1[ud]_s_=_0; L_P=0, J"P=(3)/(2)"-} to be produced in Λ{sup 0}{sub b} decays. Assuming that the mass difference between the charmed pentaquarks which differ in the orbital angular momentum L by one unit is similar to the corresponding mass difference in the charmed baryons, m[Λ{sup +}{sub c}(2625); J{sup P}=(3)/(2){sup -}]-m[Λ{sup +}{sub c}(2286); J{sup P}=(1)/(2){sup +}]

  6. Matching QCD and heavy-quark effective theory heavy-light currents at two loops and beyond

    Science.gov (United States)

    Broadhurst, D. J.; Grozin, A. G.

    1995-10-01

    Heavy-light QCD currents are matched with heavy-quark effective theory (HQET) currents at two loops and leading order in 1/m. A single formula applies to all current matchings. As a by-product, a master formula for the two-loop anomalous dimension of the QCD current q¯γ[μ1...γμn]q is obtained, yielding a new result for the tensor current. The dependence of matching coefficients on γ5 prescriptions is elucidated. Ratios of QCD matrix elements are obtained, independently of the three-loop anomalous dimension of HQET currents. The two-loop coefficient in f*B/fB =1-2αs(mb)/3π-Kbα2s/π2 +O(α3s,1/mb) is Kb=83/12+4/81π2+2/27π2ln2-1/9ζ(3)-19/54Nl +Δc=6.37+Δc, with Nl=4 light flavors, and a correction Δc=0.18+/-0.01 that takes account of the nonzero ratio mc/mb=0.28+/-0.03. Convergence of the perturbative series is poor: the fastest apparent convergence would entail αs(μ) at μ=370 MeV. ``Naive non-Abelianization'' of large-Nl results, via Nl-->Nl-33/2, gives reasonable approximations to exact two-loop results. All-order results for anomalous dimensions and matching coefficients are obtained at large β0=11=2/3Nl. Consistent cancellation between infrared- and ultraviolet-renormalon ambiguities is demonstrated.

  7. Onset transition to cold nuclear matter from lattice QCD with heavy quarks.

    Science.gov (United States)

    Fromm, M; Langelage, J; Lottini, S; Neuman, M; Philipsen, O

    2013-03-22

    Lattice QCD at finite density suffers from a severe sign problem, which has so far prohibited simulations of the cold and dense regime. Here we study the onset of nuclear matter employing a three-dimensional effective theory derived by combined strong coupling and hopping expansions, which is valid for heavy but dynamical quarks and has a mild sign problem only. Its numerical evaluations agree between a standard Metropolis and complex Langevin algorithm, where the latter is free of the sign problem. Our continuum extrapolated data approach a first order phase transition at μ(B) ≈ m(B) as the temperature approaches zero. An excellent description of the data is achieved by an analytic solution in the strong coupling limit.

  8. Fragmentation Functions for Heavy Baryons in the Recombination Model

    Institute of Scientific and Technical Information of China (English)

    彭茹

    2011-01-01

    Using the shower parton distributions determined by the recombination model, we predict the fragmentation functions for heavy baryons. Then we obtain the completed fragmentation functions of heavy quarks (c and b) splitting into their hadrons (mesons and baryons containing one heavy valence quark). The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.%Using the shower parton distributions determined by the recombination model,we predict the fragmentation functions for heavy baryons.Then we obtain the completed fragmentation functions of heavy quarks(c and b)splitting into their hadrons(mesons and baryons containing one heavy valence quark).The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.

  9. Heavy-quark pair production in gluon fusion at next-to-next-to-leading O({alpha}{sup 4}{sub s}) order. One-loop squared contributions

    Energy Technology Data Exchange (ETDEWEB)

    Kniehl, B.A.; Merebashvili, Z. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Koerner, J.G. [Mainz Univ. (Germany). Inst. fuer Physik; Rogal, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2008-09-15

    We calculate the next-to-next-to-leading order O({alpha}{sup 4}{sub s}) one-loop squared corrections to the production of heavy quark pairs in the gluon-gluon fusion process. Together with the previously derived results on the q anti q production channel the results of this paper complete the calculation of the oneloop squared contributions of the next-to-next-to-leading order O({alpha}{sup 4}{sub s}) radiative QCD corrections to the hadroproduction of heavy flavours. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in dimensional regularization. (orig.)

  10. Heavy quarks in proton

    CERN Document Server

    AUTHOR|(SzGeCERN)655637

    The measurement of prompt photon associated with a b jet in proton-proton interactions can provide us insight into the inner structure of proton. This is because precision of determination of parton distribution functions of b quark and gluon can be increased by such a measurement. The measurement of cross-section of prompt photon associated with a b jet (process $pp\\longrightarrow \\gamma + b + X$) at $\\sqrt{s}$= 8 TeV with the ATLAS detector is presented. Full 8 TeV dataset collected by ATLAS during the year 2012 was used in this analysis. Corresponding integrated luminosity is 20.3 $fb^{-1}$. Fiducial differential cross-section as a function of photon transverse momentum at particle level was extracted from data and compared with the prediction of leading order event generator Pythia 8. Cross-section extracted from data is normalised independently on the Monte Carlo prediction. Values of data distribution lie above Monte Carlo values. The difference can be explained by presence of higher order effects not ...

  11. Decays of heavy quarks

    CERN Document Server

    Rizzo, T G

    1979-01-01

    The weak decay of heavy b and t quarks is discussed using the mixing angles obtained in Fritzsch's model (1978). The author finds that the decay b to c dominates over b to u for 7

  12. Heavy-quark symmetry implies stable heavy tetraquark mesons $Q_iQ_j \\bar q_k \\bar q_l$

    Energy Technology Data Exchange (ETDEWEB)

    Eichten, Estia J.; Quigg, Chris

    2017-07-29

    For very heavy quarks $Q$, relations derived from heavy-quark symmetry predict the existence of novel narrow doubly heavy tetraquark states of the form $Q_iQ_j \\bar q_k \\bar q_l$ (subscripts label flavors), where $q$ designates a light quark. By evaluating finite-mass corrections, we predict that double-beauty states composed of $bb\\bar u \\bar d$, $bb\\bar u \\bar s$, and $bb\\bar d \\bar s$ will be stable against strong decays, whereas the double-charm states $cc \\bar q_k \\bar q_l$, mixed beauty+charm states $bc \\bar q_k \\bar q_l$, and heavier $bb \\bar q_k \\bar q_l$ states will dissociate into pairs of heavy-light mesons. Observation of a new double-beauty state through its weak decays would establish the existence of tetraquarks and illuminate the role of heavy color-antitriplet diquarks as hadron constituents.

  13. Measurement of the production cross section of heavy quark jets in association with a W boson with the ATLAS detector at the LHC

    CERN Document Server

    Vanadia, Marco

    In this thesis the production of a W boson in association with heavy-quark jets has been studied in proton-proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector at the Large Hadron Collider (LHC). For the identification of the W bosons and of the heavy quarks their semileptonic decays have been used. For this purpose, detailed studies of the muon reconstruction efficiencies of the ATLAS detector have been performed. The associated production of a W boson with bottom quark jets represents an important background for searches for the Higgs boson and beyond Standard Model physics. It is therefore important to verify experimentally the Standard Model predictions for this process in the new energy regime of the LHC. The cross sections for W boson production together with a b-jet and zero or one additional jet have been measured for the first time at LHC energies and were found to be consistent with next-to-leading order QCD predictions. The W boson production in association with a charm qu...

  14. Non-perturbative renormalization of the chromo-magnetic operator in Heavy Quark Effective Theory and the B* - B mass splitting

    CERN Document Server

    Guazzini, Damiano; Meyer, Harvey B

    2007-01-01

    We carry out the non-perturbative renormalization of the chromo-magnetic operator in Heavy Quark Effective Theory. At order 1/m of the expansion, the operator is responsible for the mass splitting between the pseudoscalar and vector B mesons. We obtain its two-loop anomalous dimension in a Schr"odinger functional scheme by successive one-loop conversions to the lattice MS scheme and the MS-bar scheme. We then compute the scale evolution of the operator non-perturbatively in the N_f=0 theory between $\\mu \\approx 0.3$ GeV and $\\mu \\approx 100$ GeV, where contact is made with perturbation theory. The overall renormalization factor that converts the bare lattice operator to its renormalization group invariant form is given for the Wilson gauge action and two standard discretizations of the heavy-quark action. As an application, we find that this factor brings the previous quenched predictions of the B* - B mass splitting closer to the experimental value than found with a perturbative renormalization. The same ren...

  15. The longitudinal heavy quark structure function F{sup Q} {sup anti} {sup Q}{sub L} in the region Q{sup 2}>>m{sup 2} at O({alpha}{sub s}{sup 3})

    Energy Technology Data Exchange (ETDEWEB)

    Bluemlein, J.; Freitas, A. de; Klein, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Neerven, W.L. van [Leiden Univ. (Netherlands). Lorentz Institute

    2006-08-15

    The logarithmic and constant contributions to the Wilson coefficient of the longitudinal heavy quark structure function to O({alpha}{sub s}{sup 3}) are calculated using mass factorization techniques in Mellin space. The small x behaviour of the Wilson coefficient is determined. Numerical illustrations are presented. (orig.)

  16. Dynamic protein assemblies in homologous recombination with single DNA molecules

    NARCIS (Netherlands)

    van der Heijden, A.H.

    2007-01-01

    What happens when your DNA breaks? This thesis describes experimental work on the single-molecule level focusing on the interaction between DNA and DNA-repair proteins, in particular bacterial RecA and human Rad51, involved in homologous recombination. Homologous recombination and its central event

  17. The role of recombination in the emergence of a complex and dynamic HIV epidemic

    Directory of Open Access Journals (Sweden)

    Morgenstern Burkhard

    2010-03-01

    Full Text Available Abstract Background Inter-subtype recombinants dominate the HIV epidemics in three geographical regions. To better understand the role of HIV recombinants in shaping the current HIV epidemic, we here present the results of a large-scale subtyping analysis of 9435 HIV-1 sequences that involve subtypes A, B, C, G, F and the epidemiologically important recombinants derived from three continents. Results The circulating recombinant form CRF02_AG, common in West Central Africa, appears to result from recombination events that occurred early in the divergence between subtypes A and G, followed by additional recent recombination events that contribute to the breakpoint pattern defining the current recombinant lineage. This finding also corrects a recent claim that G is a recombinant and a descendant of CRF02, which was suggested to be a pure subtype. The BC and BF recombinants in China and South America, respectively, are derived from recent recombination between contemporary parental lineages. Shared breakpoints in South America BF recombinants indicate that the HIV-1 epidemics in Argentina and Brazil are not independent. Therefore, the contemporary HIV-1 epidemic has recombinant lineages of both ancient and more recent origins. Conclusions Taken together, we show that these recombinant lineages, which are highly prevalent in the current HIV epidemic, are a mixture of ancient and recent recombination. The HIV pandemic is moving towards having increasing complexity and higher prevalence of recombinant forms, sometimes existing as "families" of related forms. We find that the classification of some CRF designations need to be revised as a consequence of (1 an estimated > 5% error in the original subtype assignments deposited in the Los Alamos sequence database; (2 an increasing number of CRFs are defined while they do not readily fit into groupings for molecular epidemiology and vaccine design; and (3 a dynamic HIV epidemic context.

  18. Dynamics and impact of homologous recombination on the evolution of Legionella pneumophila.

    Science.gov (United States)

    David, Sophia; Sánchez-Busó, Leonor; Harris, Simon R; Marttinen, Pekka; Rusniok, Christophe; Buchrieser, Carmen; Harrison, Timothy G; Parkhill, Julian

    2017-06-01

    Legionella pneumophila is an environmental bacterium and the causative agent of Legionnaires' disease. Previous genomic studies have shown that recombination accounts for a high proportion (>96%) of diversity within several major disease-associated sequence types (STs) of L. pneumophila. This suggests that recombination represents a potentially important force shaping adaptation and virulence. Despite this, little is known about the biological effects of recombination in L. pneumophila, particularly with regards to homologous recombination (whereby genes are replaced with alternative allelic variants). Using newly available population genomic data, we have disentangled events arising from homologous and non-homologous recombination in six major disease-associated STs of L. pneumophila (subsp. pneumophila), and subsequently performed a detailed characterisation of the dynamics and impact of homologous recombination. We identified genomic "hotspots" of homologous recombination that include regions containing outer membrane proteins, the lipopolysaccharide (LPS) region and Dot/Icm effectors, which provide interesting clues to the selection pressures faced by L. pneumophila. Inference of the origin of the recombined regions showed that isolates have most frequently imported DNA from isolates belonging to their own clade, but also occasionally from other major clades of the same subspecies. This supports the hypothesis that the possibility for horizontal exchange of new adaptations between major clades of the subspecies may have been a critical factor in the recent emergence of several clinically important STs from diverse genomic backgrounds. However, acquisition of recombined regions from another subspecies, L. pneumophila subsp. fraseri, was rarely observed, suggesting the existence of a recombination barrier and/or the possibility of ongoing speciation between the two subspecies. Finally, we suggest that multi-fragment recombination may occur in L. pneumophila

  19. Assembly and dynamics of the bacteriophage T4 homologous recombination machinery

    Directory of Open Access Journals (Sweden)

    Morrical Scott W

    2010-12-01

    Full Text Available Abstract Homologous recombination (HR, a process involving the physical exchange of strands between homologous or nearly homologous DNA molecules, is critical for maintaining the genetic diversity and genome stability of species. Bacteriophage T4 is one of the classic systems for studies of homologous recombination. T4 uses HR for high-frequency genetic exchanges, for homology-directed DNA repair (HDR processes including DNA double-strand break repair, and for the initiation of DNA replication (RDR. T4 recombination proteins are expressed at high levels during T4 infection in E. coli, and share strong sequence, structural, and/or functional conservation with their counterparts in cellular organisms. Biochemical studies of T4 recombination have provided key insights on DNA strand exchange mechanisms, on the structure and function of recombination proteins, and on the coordination of recombination and DNA synthesis activities during RDR and HDR. Recent years have seen the development of detailed biochemical models for the assembly and dynamics of presynaptic filaments in the T4 recombination system, for the atomic structure of T4 UvsX recombinase, and for the roles of DNA helicases in T4 recombination. The goal of this chapter is to review these recent advances and their implications for HR and HDR mechanisms in all organisms.

  20. Dynamics of male meiotic recombination frequency during plant development using Fluorescent Tagged Lines in Arabidopsis thaliana.

    Science.gov (United States)

    Li, Fan; De Storme, Nico; Geelen, Danny

    2017-02-13

    Meiotic homologous recombination plays a central role in creating genetic variability, making it an essential biological process relevant to evolution and crop breeding. In this study, we used pollen-specific fluorescent tagged lines (FTLs) to measure male meiotic recombination frequency during the development of Arabidopsis thaliana. Interestingly, a subset of pollen grains consistently shows loss of fluorescence expression in tested lines. Using nine independent FTL intervals, the spatio-temporal dynamics of male recombination frequency was assessed during plant development, considering both shoot type and plant age as independent parameters. In most genomic intervals assayed, male meiotic recombination frequency is highly consistent during plant development, showing no significant change between different shoot types and during plant aging. However, in some genomic regions, such as I1a and I5a, a small but significant effect of either developmental position or plant age were observed, indicating that the meiotic CO frequency in those intervals varies during plant development. Furthermore, from an overall view of all nine genomic intervals assayed, both primary and tertiary shoots show a similar dynamics of increasing recombination frequency during development, while secondary and lateral shoots remain highly stable. Our results provide new insights in the dynamics of male meiotic recombination frequency during plant development.

  1. Search for mesons and glueballs decaying into multiphoton final states produced in central hadron collisions and study of inclusive production of heavy quark mesons

    CERN Multimedia

    2002-01-01

    The experiment is aimed at:\\\\ a)\tthe search for neutral mesons and glueballs produced in central hadron-proton collisions and, simultaneously, \\\\b)\tthe study of inclusive hadronic production of neutral heavy quark mesons. \\\\ \\\\These states are observed through their decay into many photons in the 4092-cell electromagnetic Calorimeter GAMS-4000. \\\\ \\\\The NAl2 setup is supplemented with a forward magnetic spectrometer equiped with multiwire Proportional chambers (MWPC) and newly developed microstrip gas chambers (MSGC). The high spatial resolution of the latter allows to measure the momentum loss of the interacting hadron in the liquid hydrogen target (LH$_{2}$) to a precision better than 1.5 GeV/c, i.e. $3 \\times 10^{-3}$ for a 450 GeV/c proton. A system for the measurement of the time of flight (TOF) and ionization of the proton recoiling in the target completes the constraints on neutral meson production reactions. \\\\ \\\\A fast decision on the energy deposited in GAMS and the momentum of the interacting hadro...

  2. Perturbative stability of the QCD predictions for the ratio $R=F_L/F_T$ and azimuthal asymmetry in heavy-quark leptoproduction

    CERN Document Server

    Ivanov, N Ya

    2012-01-01

    We analyze the perturbative and parametric stability of the QCD predictions for the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ and azimuthal $\\cos(2\\varphi)$ asymmetry in heavy-quark leptoproduction. Our analysis shows that large radiative corrections to the structure functions cancel each other in their ratio $R(x,Q^2)$ and azimuthal asymmetry with good accuracy. As a result, the NLO contributions to the Callan-Gross ratio and $\\cos(2\\varphi)$ asymmetry are less than 10% in a wide region of the variables $x$ and $Q^2$. We provide compact analytic predictions for $R(x,Q^2)$ and asymmetry in the case of low $x\\ll 1$. Simple formulae connecting the high-energy behavior of the Callan-Gross ratio and azimuthal asymmetry with the low-$x$ asymptotics of the gluon density in the target are derived. It is shown that the obtained hadron-level predictions for $R(x,Q^2)$ and azimuthal asymmetry are stable at $x\\ll 1$ under the DGLAP evolution of the gluon distribution function. Concerning the experimental aspects, we propose...

  3. Heavy-quark production and elliptic flow in Au$+$Au collisions at $\\sqrt{s_{_{NN}}}=62.4$ GeV

    CERN Document Server

    Adare, A; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Ta'ani, H; Alexander, J; Angerami, A; Aoki, K; Apadula, N; Aramaki, Y; Asano, H; Aschenauer, E C; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bannier, B; Barish, K N; Bassalleck, B; Bathe, S; Baublis, V; Baumgart, S; Bazilevsky, A; Belmont, R; Berdnikov, A; Berdnikov, Y; Bing, X; Blau, D S; Boyle, K; Brooks, M L; Buesching, H; Bumazhnov, V; Butsyk, S; Campbell, S; Castera, P; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Choudhury, R K; Christiansen, P; Chujo, T; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Connors, M; Csanád, M; Csörgő, T; Dairaku, S; Datta, A; Daugherity, M S; David, G; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Ding, L; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; D'Orazio, L; Edwards, S; Efremenko, Y V; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fusayasu, T; Gainey, K; Gal, C; Garishvili, A; Garishvili, I; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gunji, T; Guo, L; Gustafsson, H -Å; Hachiya, T; Haggerty, J S; Hahn, K I; Hamagaki, H; Hanks, J; Hashimoto, K; Haslum, E; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Huang, S; Ichihara, T; Iinuma, H; Ikeda, Y; Imrek, J; Inaba, M; Iordanova, A; Isenhower, D; Issah, M; Ivanishchev, D; Jacak, B V; Javani, M; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kim, B I; Kim, C; Kim, D J; Kim, E -J; Kim, H J; Kim, K -B; Kim, Y -J; Kim, Y K; Kinney, E; Kiss, Á; Kistenev, E; Klatsky, J; Kleinjan, D; Kline, P; Komatsu, Y; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Král, A; Krizek, F; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, B; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Leitgab, M; Lewis, B; Lim, S H; Levy, L A Linden; Liu, M X; Love, B; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Masumoto, S; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyachi, Y; Miyasaka, S; Mohanty, A K; Moon, H J; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagae, T; Nagamiya, S; Nagle, J L; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Nederlof, A; Nihashi, M; Nouicer, R; Novitzky, N; Nyanin, A S; O'Brien, E; Ogilvie, C A; Okada, K; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Pate, S F; Patel, L; Pei, H; Peng, J -C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Sahlmueller, B; Saito, N; Sakaguchi, T; Samsonov, V; Sano, M; Sarsour, M; Sawada, S; Sedgwick, K; Seidl, R; Sen, A; Seto, R; Sharma, D; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Todoroki, T; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Tsuji, T; Vale, C; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Whitaker, S; White, S N; Winter, D; Wolin, S; Woody, C L; Wysocki, M; Yamaguchi, Y L; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; You, Z; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A

    2014-01-01

    We present measurements of electrons and positrons from the semileptonic decays of heavy-flavor hadrons at midrapidity ($|y|<$ 0.35) in Au$+$Au collisions at $\\sqrt{s_{_{NN}}}=62.4$ GeV. The data were collected in 2010 by the PHENIX experiment that included the new hadron-blind detector. The invariant yield of electrons from heavy-flavor decays is measured as a function of transverse momentum in the range $1heavy-quark production at this low beam energy. The $v_2$ of electrons from heavy-flavor decays is nonzero when averaged between $1.3

  4. Exciton recombination dynamics in single ZnO tetrapods

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes-Silva, Lígia C. [Departamento de Física de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Martín, Maria D.; Meulen, Herko P. van der; Calleja, José M.; Viña, Luis [Departamento de Física de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid, Spain and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Klopotowski, Lukasz [Polish Academy of Sciences, Institute of Physics, 02-668 Warsaw (Poland)

    2013-12-04

    We present the optical properties of individual ZnO tetrapods as a function of excitation power and temperature by time-integrated and time-resolved spectroscopy. At 10K, we identify the different excitonic transitions by both their characteristic energy and their excitation power dependence. When we increase the tetrapod temperature we observe that the emission intensity decrease and occur a red shift of the emission energies. Our time-resolved studies confirm the predominance of the radiative recombination at low temperatures (< 45 K). Increasing the temperature opens up the non-radiative channels, which are evidenced by a much faster decay time.

  5. Exciton recombination dynamics in single ZnO tetrapods

    Science.gov (United States)

    Fernandes-Silva, Lígia C.; Martín, Maria D.; van der Meulen, Herko P.; Klopotowski, Lukasz; Calleja, José M.; Viña, Luis

    2013-12-01

    We present the optical properties of individual ZnO tetrapods as a function of excitation power and temperature by time-integrated and time-resolved spectroscopy. At 10K, we identify the different excitonic transitions by both their characteristic energy and their excitation power dependence. When we increase the tetrapod temperature we observe that the emission intensity decrease and occur a red shift of the emission energies. Our time-resolved studies confirm the predominance of the radiative recombination at low temperatures (< 45 K). Increasing the temperature opens up the non-radiative channels, which are evidenced by a much faster decay time.

  6. Femtosecond dynamics of fundamental reaction processes in liquids: Proton transfer, geminate recombination, isomerization and vibrational relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Benjamin Joel [Univ. of California, Berkeley, CA (United States)

    1992-11-01

    The fast excited state intramolecular proton transfer of 3-hydroxyflavone is measured and effects of external hydrogen-bonding interactions on the proton transfer are studied. The proton transfer takes place in ~240 fsec in nonpolar environments, but becomes faster than instrumental resolution of 110 fsec in methanol solution. The dynamics following photodissociation of CH2I2 and other small molecules provide the first direct observations of geminate recombination. The recombination of many different photodissociating species occurs on a ~350 fsec time scale. Results show that recombination yields but not rates depend on the solvent environment and suggest that recombination kinetics are dominated by a single collision with surrounding solvent cage. Studies of sterically locked phenyl-substituted butadienes offer new insights into the electronic structure and isomerization behavior of conjugated polyenes. Data show no simple correlation between hinderance of specific large amplitude motions and signatures of isomerizative behavior such as viscosity dependent excited state lifetimes, implying that the isomerization does not provide a suitable for simple condensed phase reaction rate theories. The spectral dynamics of a photochromic spiropyran indicate that recombination, isomerization and vibrational relaxation all play important roles in photoreactivity of complex molecules. The interplay of these microscopic phenomena and their effect on macroscopic properties such as photochromism are discussed. All the results indicate that the initial steps of the photochromic reaction process occur extremely rapidly. Laser system and computer codes for data analysis are discussed.

  7. On quantitative analysis of interband recombination dynamics: Theory and application to bulk ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Lettieri, S. [Institute for Superconductors, Oxides and Innovative Materials, National Research Council (CNR-SPIN), U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Capello, V.; Santamaria, L. [Physics Department, University of Naples “Federico II,” Via Cintia I-80126 Napoli (Italy); Maddalena, P. [Institute for Superconductors, Oxides and Innovative Materials, National Research Council (CNR-SPIN), U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Physics Department, University of Naples “Federico II,” Via Cintia I-80126 Napoli (Italy)

    2013-12-09

    The issue of the quantitative analysis of time-resolved photoluminescence experiments is addressed by developing and describing two approaches for determination of unimolecular lifetime, bimolecular recombination coefficient, and equilibrium free-carrier concentration, based on a quite general second-order expression of the electron-hole recombination rate. Application to the case of band-edge emission of ZnO single crystals is reported, evidencing the signature of sub-nanosecond second-order recombination dynamics for optical transitions close to the interband excitation edge. The resulting findings are in good agreement with the model prediction and further confirm the presence, formerly evidenced in literature by non-optical methods, of near-surface conductive layers in ZnO crystals with sheet charge densities of about 3–5×10{sup 13} cm{sup −2}.

  8. Measurement of the cross section for direct-photon production in association with a heavy quark in $p\\bar{p}$ collisions at $\\sqrt{s}$ = 1.96 TeV

    CERN Document Server

    Aaltonen, T; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chokheli, D; Cho, K; Ciocci, M A; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; d'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Eusebi, R; Farrington, S; Fernandez Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Goldin, D; Gold, M; Golossanov, A; Gomez-Ceballos, G; Gomez, G; Goncharov, M; Gonzalez Lopez, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harrington-Taber, T; Harr, R F; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Junk, T R; Jun, S Y; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kimura, N; Kim, Y J; Kim, Y K; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leone, S; Leo, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lysak, R; Lys, J; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, P; Martinez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernandez, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; Stancari, M; St. Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vazquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizan, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C, III; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2013-01-01

    We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of $\\sqrt{s}=1.96$ TeV proton-antiproton collisions corresponding to 9.1 fb$^{-1}$ of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering photon transverse momentum between 30 and 300 GeV, photon rapidities $|y^{\\gamma}|20$ GeV, and jet rapidities $|y^{jet}|<1.5$. The results are compared with several theoretical predictions.

  9. Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark in pp¯ Collisions at s=1.96TeV

    Science.gov (United States)

    Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Ciocci, M. A.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; De Barbaro, P.; Demortier, L.; Deninno, M.; d'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Eusebi, R.; Farrington, S.; Fernández Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucà, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, P.; Martínez, M.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Ranjan, N.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sinervo, P.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Song, H.; Sorin, V.; Stancari, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vázquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizán, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S. M.; Warburton, A.; Waters, D.; Wester, W. C., III; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Zanetti, A. M.; Zeng, Y.; Zhou, C.; Zucchelli, S.

    2013-07-01

    We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of s=1.96TeV proton-antiproton collisions corresponding to 9.1fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|20GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions.

  10. Measurement of the cross section for direct-photon production in association with a heavy quark in $p\\bar{p}$ collisions at $\\sqrt{s}$ = 1.96 TeV

    CERN Document Server

    Aaltonen, T.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K.R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H.S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y.C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Ciocci, M.A.; Clark, A.; Clarke, C.; Convery, M.E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C.A.; Cox, D.J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Demortier, L.; Deninno, M.; d'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J.R.; D'Onofrio, M.; Donati, S.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Eusebi, R.; Farrington, S.; Fernandez Ramos, J.P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J.C.; Frisch, H.; Funakoshi, Y.; Garfinkel, A.F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C.M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; Gonzalez Lopez, O.; Gorelov, I.; Goshaw, A.T.; Goulianos, K.; Gramellini, E.; Grinstein, S.; Grosso-Pilcher, C.; Group, R.C.; Guimaraes da Costa, J.; Hahn, S.R.; Han, J.Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R.F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R.E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E.J.; Jindariani, S.; Jones, M.; Joo, K.K.; Jun, S.Y.; Junk, T.R.; Kambeitz, M.; Kamon, T.; Karchin, P.E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D.H.; Kim, H.S.; Kim, J.E.; Kim, M.J.; Kim, S.B.; Kim, S.H.; Kim, Y.J.; Kim, Y.K.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D.J.; Konigsberg, J.; Kotwal, A.V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A.T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H.S.; Lee, J.S.; Leo, S.; Leone, S.; Lewis, J.D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, P.; Martinez, M.; Matera, K.; Mattson, M.E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C.S.; Moore, R.; Morello, M.J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S.Y.; Norniella, O.; Oakes, L.; Oh, S.H.; Oh, Y.D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T.J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Ranjan, N.; Redondo Fernandez, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J.L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W.K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E.E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S.Z.; Shears, T.; Shepard, P.F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sinervo, P.; Sliwa, K.; Smith, J.R.; Snider, F.D.; Song, H.; Sorin, V.; Stancari, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P.K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vazquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizan, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S.M.; Warburton, A.; Waters, D.; Wester, W.C., III; Whiteson, D.; Wicklund, A.B.; Wilbur, S.; Williams, H.H.; Wilson, J.S.; Wilson, P.; Winer, B.L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U.K.; Yang, Y.C.; Yao, W.M.; Yeh, G.P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G.B.; Yu, I.; Zanetti, A.M.; Zeng, Y.; Zhou, C.; Zucchelli, S.

    2013-07-25

    We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of $\\sqrt{s}=1.96$ TeV proton-antiproton collisions corresponding to 9.1 fb$^{-1}$ of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering photon transverse momentum between 30 and 300 GeV, photon rapidities $|y^{\\gamma}|20$ GeV, and jet rapidities $|y^{jet}|<1.5$. The results are compared with several theoretical predictions.

  11. Production and semileptonic decays of heavy quarks at LEP with the ALEPH detector; Production et desintegrations semileptoniques des quarks lourds au LEP avec le detecteur ALEPH

    Energy Technology Data Exchange (ETDEWEB)

    Monteil, St.

    1996-05-15

    The four LEP experiments have collected nearly 16 million Z. These very high statistics allow to perform a large field of precision tests of the standard model of electroweak interactions with a very high accuracy. One of the most promising channel in order to observe a deviation with respect to the SM predictions is the study of the b quark production in the Z boson decay. Two observables are of interest in that respect: the Z partial decay width in b quarks, denoted R{sub b} and the b forward-backward asymmetry. A measurement of R{sub b} using both the long lifetime of b hadrons and the kinematical properties of the leptons coming from the semileptonic decays of b hadrons is presented in the first part of this document. The c partial decay width, denoted R{sub c}, is simultaneously measured. 1.3 million of Z have been analyzed and the following results have been obtained: R{sub b} = 21.82 {+-}0.25{+-}0.24%; R{sub c} = 16.02{+-}0.56{+-}1.41%. The former error is statistical and the latter systematics. These two results are in good agreement with the SM predictions. The semileptonic branching ratios of the b hadrons, denoted Br(b {yields} l{sup -}) for the primary decay and Br(b {yields} c {yields} l{sup +}), for the cascade decay, on one hand, and the B{sup 0} {r_reversible} B-bar{sup 0} mixing parameter, denoted X, on another hand are needed in the b asymmetry measurement with the leptons. The second part of this document is devoted to their measurement. This is done by using both lifetime of b hadrons and kinematical characteristics of the leptons coming from semileptonic decays of b hadrons. The following results have been obtained: Br(b {yields} l) 11.03 {+-} 0.07 {+-} 0.21 + 0.24%- 0.17%; Br(b {yields} C {yields} l) 7.84 {+-} 0.12 {+-} 0.30 + 0.34% - 0.43%; X 12.62 {+-} 0.56 {+-} 0.24 + 0.42% - 0.41%. Those results are found in a good agreement with the heavy quark theory predictions. (Abstract Truncated)

  12. Molecular Dynamics Simulations of Surface Processes: Oxygen Recombination on Silica Surfaces at High Temperature

    Science.gov (United States)

    2007-07-01

    size-scalable cluster approach with SixOy clusters of increasing size cleaved from the β- cristobalite unit cell. In this study the hybrid Hartree...values of the β- cristobalite cell and extending the Molecular Dynamics Simulations of Surface Processes: Oxygen Recombination on Silica Surfaces at... cristobalite surface is reported as a function of the distance of the N atom from the Si active atom. The dashed line shows the interaction

  13. Excitation rates of heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Canal, C.A.G.; Santangelo, E.M.; Ducati, M.B.G.

    1985-06-01

    We obtain the production rates for c, b, and t quarks in deep-inelastic neutrino- (antineutrino-) nucleon interactions, in the standard six-quark model with left-handed couplings. The results are obtained with the most recent mixing parameters and we include a comparison between quark parametrizations. The excitations are calculated separately for each flavor, allowing the understanding of the role of threshold effects when considered through different rescaling variables.

  14. Heavy Quark Asymmetries at LEP

    CERN Document Server

    Halley, A W

    1999-01-01

    Measurements of b and c quark asymmetries using data collected at LEP 1 are described. The relative merits of each of the individual techniques used is emphasised as is the most profitable way of combining them. Effects of radiative corrections are discussed, together with the impact of these measurements on global electroweak fits used to estimate the expected mass of the Higgs boson.

  15. Polarization in heavy quark decays

    Energy Technology Data Exchange (ETDEWEB)

    Alimujiang, K.

    2006-07-01

    In this thesis I concentrate on the angular correlations in top quark decays and their next.to.leading order (NLO) QCD corrections. I also discuss the leading.order (LO) angular correlations in unpolarized and polarized hyperon decays. In the first part of the thesis I calculate the angular correlation between the top quark spin and the momentum of decay products in the rest frame decay of a polarized top quark into a charged Higgs boson and a bottom quark in Two-Higgs-Doublet-Models: t({up_arrow}) {yields} b + H{sup +}. I provide closed form formulae for the O({alpha}{sub s}) radiative corrections to the unpolarized and the polar correlation functions for m{sub b}{ne}0 and m{sub b}=0. In the second part I concentrate on the semileptonic rest frame decay of a polarized top quark into a bottom quark and a lepton pair: t({up_arrow}){yields}X{sub b}+l{sup +}+{nu}{sub l}. I present closed form expressions for the O({alpha}{sub s}) radiative corrections to the unpolarized part and the polar and azimuthal correlations for m{sub b}{ne}0 and m{sub b}=0. In the last part I turn to the angular distribution in semileptonic hyperon decays. Using the helicity method I derive complete formulas for the leading order joint angular decay distributions occurring in semileptonic hyperon decays including lepton mass and polarization effects. (orig.)

  16. Heavy quark physics from LEP

    Energy Technology Data Exchange (ETDEWEB)

    Dornan, P.J. [Imperial College of Science Technology and Medicine, London (United Kingdom)

    1997-01-01

    A review of some of the latest results on heavy flavor physics from the LEP Collaborations is presented. The emphasis is on B physics, particularly new results and those where discrepancies is given of the many techniques which have been developed to permit these analyses.

  17. Nonlinear photoluminescence in monolayer WS2: parabolic emission and excitation fluence-dependent recombination dynamics.

    Science.gov (United States)

    Fan, Xiaopeng; Zheng, Weihao; Liu, Hongjun; Zhuang, Xiujuan; Fan, Peng; Gong, Yanfang; Li, Honglai; Wu, Xueping; Jiang, Ying; Zhu, Xiaoli; Zhang, Qinglin; Zhou, Hong; Hu, Wei; Wang, Xiao; Duan, Xiangfeng; Pan, Anlian

    2017-06-01

    Recombination dynamics during photoluminescence (PL) in two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) are complicated and can be easily affected by the surroundings because of their atomically thin structures. Herein, we studied the excitation power and temperature dependence of the recombination dynamics on the chemical vapor deposition-grown monolayer WS2via a combination of Raman, PL, and time-resolved PL spectroscopies. We found a red shift and parabolic intensity increase in the PL emission of the monolayer WS2 with the increasing excitation power and the decay time constants corresponding to the recombination of trions and excitons from transient PL dynamics. We attributed the abovementioned nonlinear changes in the PL peak positions and intensities to the combination of increasing carrier interaction and band structure renormalization rather than to the thermal effect from a laser. Furthermore, the excitation power-dependent Raman measurements support our conclusion. These findings and understanding will provide important information for the development of TMD-based optoelectronics and photonics.

  18. Emergence of recombinant forms in geographic regions with co-circulating HIV subtypes in the dynamic HIV-1 epidemic

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming [Los Alamos National Laboratory; Letiner, Thomas K [Los Alamos National Laboratory; Korber, Bette T [Los Alamos National Laboratory; Foley, Brian [Los Alamos National Laboratory

    2009-01-01

    We have reexamined the subtype designations of {approx}10,000 subtype A, B, C, G, and AG, BC, BF recombinant sequences, and compared the results of the new analysis with their published designations. Intersubtype recombinants dominate HIV epidemics in three different geographical regions. The circulating recombinant from (CRF) CRF02-AG, common in West Central Africa, appears to result from a recombination event that occurred early in the divergence between subtypes A and G, although additional more recent recombination events may have contributed to the breakpoint pattern in this recombinant lineage as well. The Chinese recombinant epidemic strains CRF07 and CRF08, in contrast, result from recent recombinations between more contemporary strains. Nevertheless, CRF07 and CRF08 contributed to many subsequent recombination events. The BF recombinant epidemics in two HIV-1 epicenters in South America are not independent and BF epidemics in South America have an unusually high fraction of unique recombinant forms (URFs) that have each been found only once and carry distinctive breakpoints. Taken together, these analyses reveal a complex and dynamic picture of the current HIV-1 epidemic, and suggest a means of grouping and tracking relationships between viruses through preservation of shared breakpints.

  19. Structure and Dynamics of Single-isoform Recombinant Neuronal Human Tubulin.

    Science.gov (United States)

    Vemu, Annapurna; Atherton, Joseph; Spector, Jeffrey O; Szyk, Agnieszka; Moores, Carolyn A; Roll-Mecak, Antonina

    2016-06-17

    Microtubules are polymers that cycle stochastically between polymerization and depolymerization, i.e. they exhibit "dynamic instability." This behavior is crucial for cell division, motility, and differentiation. Although studies in the last decade have made fundamental breakthroughs in our understanding of how cellular effectors modulate microtubule dynamics, analysis of the relationship between tubulin sequence, structure, and dynamics has been held back by a lack of dynamics measurements with and structural characterization of homogeneous isotypically pure engineered tubulin. Here, we report for the first time the cryo-EM structure and in vitro dynamics parameters of recombinant isotypically pure human tubulin. α1A/βIII is a purely neuronal tubulin isoform. The 4.2-Å structure of post-translationally unmodified human α1A/βIII microtubules shows overall similarity to that of heterogeneous brain microtubules, but it is distinguished by subtle differences at polymerization interfaces, which are hot spots for sequence divergence between tubulin isoforms. In vitro dynamics assays show that, like mosaic brain microtubules, recombinant homogeneous microtubules undergo dynamic instability, but they polymerize slower and have fewer catastrophes. Interestingly, we find that epitaxial growth of α1A/βIII microtubules from heterogeneous brain seeds is inefficient but can be fully rescued by incorporating as little as 5% of brain tubulin into the homogeneous α1A/βIII lattice. Our study establishes a system to examine the structure and dynamics of mammalian microtubules with well defined tubulin species and is a first and necessary step toward uncovering how tubulin genetic and chemical diversity is exploited to modulate intrinsic microtubule dynamics.

  20. Search for pair and single production of new heavy quarks that decay to a $Z$ boson and a third-generation quark in $pp$ collisions at $\\sqrt{s}=8$ TeV with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Almond, John; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Auerbach, Benjamin; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baas, Alessandra; Bacci, Cesare; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bain, Travis; Baines, John; Baker, Oliver Keith; Balek, Petr; Balli, Fabrice; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Bartsch, Valeria; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batley, Richard; Battaglia, Marco; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Katharina; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Beringer, Jürg; Bernard, Clare; Bernat, Pauline; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertsche, Carolyn; Bertsche, David; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Black, Curtis; Black, James

    2014-01-01

    A search is presented for the production of new heavy quarks that decay to a $Z$ boson and a third-generation Standard Model quark. In the case of a new charge +2/3 quark ($T$), the decay targeted is $T \\rightarrow Zt$, while the decay targeted for a new charge -1/3 quark ($B$) is $B \\rightarrow Zb$. The search is performed with a dataset corresponding to 20.3 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s}=8$ TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Selected events contain a high transverse momentum $Z$ boson candidate reconstructed from a pair of oppositely charged same-flavor leptons (electrons or muons), and are analyzed in two channels defined by the absence or presence of a third lepton. Hadronic jets, in particular those with properties consistent with the decay of a $b$-hadron, are also required to be present in selected events. Different requirements are made on the jet activity in the event in order to enhance the sensitivity to either heavy quark pair production me...

  1. Search for pair and single production of new heavy quarks that decay to a $Z$ boson and a third-generation quark in $pp$ collisions at $\\sqrt{s}=8$ TeV with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Almond, John; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Auerbach, Benjamin; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baas, Alessandra; Bacci, Cesare; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bain, Travis; Baines, John; Baker, Oliver Keith; Balek, Petr; Balli, Fabrice; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Bartsch, Valeria; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batley, Richard; Battaglia, Marco; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Katharina; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Beringer, Jürg; Bernard, Clare; Bernat, Pauline; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertsche, Carolyn; Bertsche, David; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Black, Curtis; Black, James

    2014-11-19

    A search is presented for the production of new heavy quarks that decay to a $Z$ boson and a third-generation Standard Model quark. In the case of a new charge +2/3 quark ($T$), the decay targeted is $T \\rightarrow Zt$, while the decay targeted for a new charge -1/3 quark ($B$) is $B \\rightarrow Zb$. The search is performed with a dataset corresponding to 20.3 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s}=8$ TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Selected events contain a high transverse momentum $Z$ boson candidate reconstructed from a pair of oppositely charged same-flavor leptons (electrons or muons), and are analyzed in two channels defined by the absence or presence of a third lepton. Hadronic jets, in particular those with properties consistent with the decay of a $b$-hadron, are also required to be present in selected events. Different requirements are made on the jet activity in the event in order to enhance the sensitivity to either heavy quark pair production me...

  2. Search for pair and single production of new heavy quarks that decay to a $Z$ boson and a third generation quark in $pp$ collisions at $\\sqrt{s}=8$ TeV with the ATLAS detector

    CERN Document Server

    The ATLAS collaboration

    2014-01-01

    A search is presented for the production of new heavy quarks that decay to a $Z$ boson and a third generation Standard Model quark. In the case of a new charge $+2/3$ quark ($T$), the decay targeted is $T \\rightarrow Zt$, while the decay targeted for a new charge $-1/3$ quark ($B$) is $B \\rightarrow Zb$. The search uses a dataset corresponding to $20.3~\\mathrm{fb}^{-1}$ of $pp$ collisions at $\\sqrt{s}=8$~TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Selected events contain a high transverse momentum $Z$ boson candidate reconstructed from a pair of oppositely-charged same-flavor leptons (electrons or muons), and are analyzed in two channels defined by the presence or absence of a third lepton. Hadronic jets, in particular those with properties consistent with the decay of a $b$ hadron, are also required to be present in selected events. Different requirements are made on the jet activity in the event in order to enhance the sensitivity to either heavy quark pair production med...

  3. Femtosecond Dynamics of Fundamental Reaction Processes in Liquids: Proton Transfer, Geminate Recombination, Isomerization and Vibrational Relaxation.

    Science.gov (United States)

    Schwartz, Benjamin Joel

    Femtosecond and picosecond transient absorption spectroscopy are used to probe several fundamental aspects of chemical reactivity in the condensed phase including proton transfer, germinate recombination, isomerization and vibrational relaxation. The fast excited state intramolecular proton transfer of 3-hydroxyflavone is measured for the first time, and the effects of external hydrogen-bonding interactions on the proton transfer are studied in detail. The proton transfer takes place in ~240 fsec in non-polar environments, but becomes faster than the instrumental resolution of 110 fsec in methanol solutions. A simple model is proposed to explain these results. The dynamics following photodissociation of CH _2I_2 and other small molecules provide the first direct observations of germinate recombination. The recombination of many different photodissociating species occurs on a ~350 fsec time scale. Results also show that recombination yields but not rates depend on the molecular details of the solvent environment and suggest that recombination kinetics are dominated by a single collision with the surrounding solvent cage. Studies of sterically locked phenyl-substituted butadienes offer new insights into the electronic structure and isomerization behavior of conjugated polyenes. The data show no simple correlation between the hinderance of specific large amplitude motions and signatures of isomerizative behavior such as viscosity dependent excited state lifetimes. This strongly implies that the isomerization of these systems does not provide a suitable testing ground for simple condensed phase reaction rate theories. The spectral dynamics of a photochromic spiropyran indicate that recombination, isomerization and vibrational relaxation all play important roles in the photoreactivity of complex molecules. The interplay of these microscopic phenomena and their effect on macroscopic properties such as photochromism are discussed. All the results indicate that the initial

  4. Ultrafast dynamics of charge carrier photogeneration and geminate recombination in conjugated polymer:fullerene solar cells

    Science.gov (United States)

    Müller, J. G.; Lupton, J. M.; Feldmann, J.; Lemmer, U.; Scharber, M. C.; Sariciftci, N. S.; Brabec, C. J.; Scherf, U.

    2005-11-01

    We investigate the nature of ultrafast exciton dissociation and carrier generation in acceptor-doped conjugated polymers. Using a combination of two-pulse femtosecond spectroscopy with photocurrent detection, we compare the exciton dissociation and geminate charge recombination dynamics in blends of two conjugated polymers, MeLPPP [methyl-substituted ladder-type poly( p -phenylene)] and MDMO-PPV [poly(2-methoxy,5-(3,7-dimethyloctyloxy)-1,4-phenylenevinylene], with the electron accepting fullerene derivative PCBM [1-(3-methoxycarbonyl)-propyl-1-phenyl- (6,6)C61 ]. This technique allows us to distinguish between free charge carriers and Coulombically bound polaron pairs. Our results highlight the importance of geminate pair recombination in photovoltaic devices, which limits the device performance. The comparison of different materials allows us to address the dependence of geminate recombination on the film morphology directly at the polymer:fullerene interface. We find that in the MeLPPP:PCBM blend exciton dissociation generates Coulombically bound geminate polaron pairs with a high probability for recombination, which explains the low photocurrent yield found in these samples. In contrast, in the highly efficient MDMO-PPV:PCBM blend the electron transfer leads to the formation of free carriers. The anisotropy dynamics of electronic transitions from neutral and charged states indicate that polarons in MDMO-PPV relax to delocalized states in ordered domains within 500fs . The results suggest that this relaxation enlarges the distance of carrier separation within the geminate pair, lowering its binding energy and favoring full dissociation. The difference in geminate pair recombination concurs with distinct dissociation dynamics. The electron transfer is preceded by exciton migration towards the PCBM sites. In MeLPPP:PCBM the exciton migration time decays smoothly with increasing PCBM concentration, indicating a trap-free exciton hopping. In MDMO-PPV:PCBM, however

  5. Testing dynamic stabilisation in complex Langevin simulations

    CERN Document Server

    Attanasio, Felipe

    2016-01-01

    Complex Langevin methods have been successfully applied in theories that suffer from a sign problem such as QCD with a chemical potential. We present and illustrate a novel method (dynamic stabilisation) that ensures that Complex Langevin simulations stay close to the SU(3) manifold, which lead to correct and improved results in the framework of pure Yang-Mills simulations and QCD in the limit of heavy quarks.

  6. Recombination dynamics of optically excited charge carriers in bulk MoS2

    Science.gov (United States)

    Völzer, Tim; Lütgens, Matthias; Fennel, Franziska; Lochbrunner, Stefan

    2017-10-01

    Transition metal dichalcogenides (TMDCs), such as MoS2, are promising candidates for optoelectronic or catalytic applications. On that account, a detailed characterization of the electronic dynamics in these materials is of pivotal importance. Here, we investigate the temporal evolution of an excited carrier population by all-optical pump-probe spectroscopy. On the sub-picosecond time scale we observe thermal relaxation of the excited carriers by electron–phonon coupling. The dynamics on the nanosecond time scale can be understood in terms of defect-assisted Auger recombination over a broad carrier density regime spanning more than one order of magnitude. Hence, our results emphasize the importance of defect states for electronic processes in TMDCs at room temperature.

  7. Determination of a dynamic feeding strategy for recombinant Pichia pastoris strains.

    Science.gov (United States)

    Spadiut, Oliver; Dietzsch, Christian; Herwig, Christoph

    2014-01-01

    The knowledge of certain strain specific parameters of recombinant P. pastoris strains is required to be able to set up a feeding regime for fed-batch cultivations. To date, these parameters are commonly determined either by time-consuming and labor-intensive continuous cultivations or by several, consecutive fed-batch cultivations. Here, we describe a fast method based on batch experiments with methanol pulses to extract certain strain characteristic parameters, which are required to set up a dynamic feeding strategy for P. pastoris strains based on specific substrate uptake rate (q(s)). We further describe in detail the course of actions which have to be taken to obtain the desired dynamics during feeding.

  8. Measurement of the cross section for direct-photon production in association with a heavy quark in pp[over ¯] collisions at sqrt[s]=1.96  TeV.

    Science.gov (United States)

    Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Ciocci, M A; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; De Barbaro, P; Demortier, L; Deninno, M; d'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Eusebi, R; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucà, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, P; Martínez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; Stancari, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2013-07-26

    We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of sqrt[s]=1.96  TeV proton-antiproton collisions corresponding to 9.1  fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|quark-jet transverse momentum pTjet>20  GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions.

  9. Search for heavy quarks decaying into a top quark and a W or Z boson using lepton + jets events in pp collisions at sqrt{s}=7 TeV

    Science.gov (United States)

    Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Aguilo, E.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Pernicka, M.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Staykova, Z.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Reis, T.; Thomas, L.; Vander Marcken, G.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Verwilligen, P.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Schul, N.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins Junior, M.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá Júnior, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Oguri, V.; Prado Da Silva, W. L.; Santoro, A.; Soares Jorge, L.; Sznajder, A.; Anjos, T. S.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Gomez, J. P.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Raidal, M.; Rebane, L.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Karjalainen, A.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sgandurra, L.; Sordini, V.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Anagnostou, G.; Autermann, C.; Beranek, S.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.

    2013-01-01

    Results are presented from a search for the pair-production of heavy quarks, Qoverline{Q} , that decay exclusively into a top quark and a W or Z boson. The search is performed using a sample of proton-proton collisions at sqrt{s}=7 TeV corresponding to an integrated luminosity of 5.0 fb-1, collected by the Compact Muon Solenoid experiment. The signal region is defined using a sample of events containing one electron or muon, missing transverse momentum, and at least four jets with large transverse momenta, where one jet is likely to originate from the decay of a bottom quark. No significant excess of events is observed with respect to the standard model expectations. Assuming a strong pair-production mechanism, quark masses below 675 (625) GeV decaying into tW (tZ) are excluded at the 95 % confidence level.[Figure not available: see fulltext.

  10. Search for pair production of a new heavy quark that decays into a $W$ boson and a light quark in $pp$ collisions at $\\sqrt{s} = 8$ TeV with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdinov, Ovsat; Aben, Rosemarie; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Affolder, Tony; Agatonovic-Jovin, Tatjana; Agricola, Johannes; Aguilar-Saavedra, Juan Antonio; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Alkire, Steven Patrick; Allbrooke, Benedict; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Άlvarez Piqueras, Damián; Alviggi, Mariagrazia; Amadio, Brian Thomas; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anders, John Kenneth; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Arabidze, Giorgi; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arduh, Francisco Anuar; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Axen, Bradley; Ayoub, Mohamad Kassem; Azuelos, Georges; Baak, Max; Baas, Alessandra; Baca, Matthew John; Bacci, Cesare; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bain, Travis; Baines, John; Baker, Oliver Keith; Baldin, Evgenii; Balek, Petr; Balestri, Thomas; Balli, Fabrice; Balunas, William Keaton; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Barak, Liron; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnes, Sarah Louise; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Basalaev, Artem; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batista, Santiago Juan; Batley, Richard; Battaglia, Marco; Bauce, Matteo; Bauer, Florian; Bawa, Harinder Singh; Beacham, James Baker; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Kathrin; Becker, Maurice; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Janna Katharina; Belanger-Champagne, Camille; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bender, Michael; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Bentvelsen, Stan; Beresford, Lydia; Beretta, Matteo; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Beringer, Jürg; Bernard, Clare; Bernard, Nathan Rogers; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertsche, Carolyn; Bertsche, David; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia Bylund, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bevan, Adrian John; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Biedermann, Dustin; Bieniek, Stephen Paul; Biesuz, Nicolo Vladi; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet

    2015-01-01

    A search is presented for pair production of a new heavy quark ($Q$) that decays into a $W$ boson and a light quark ($q$) in the final state where one $W$ boson decays leptonically (to an electron or muon plus a neutrino) and the other $W$ boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s} = 8$ TeV collected by the ATLAS detector at the LHC. No evidence of $Q\\bar{Q}$ production is observed. New chiral quarks with masses below 690 GeV are excluded at 95% confidence level, assuming BR$(Q\\to Wq)=1$. Results are also interpreted in the context of vectorlike quark models, resulting in the limits on the mass of a vectorlike quark in the two-dimensional plane of BR$(Q\\to Wq)$ versus BR$(Q\\to Hq)$.

  11. LEP1 measurement of heavy quark forward-backward asymmetries with Opal detector; Mesure de l`asymetrie avant-arriere des quarks lourds a LEP1 avec le detecteur Opal

    Energy Technology Data Exchange (ETDEWEB)

    Lafoux, H.

    1996-04-30

    Using all data collected by OPAL during the first phase of LEP operation, called LEP1, we have measured the b and c quark forward-backward asymmetries on and around the Z{sup 0} peak. The measurement, which is based on prompt leptons produced in semileptonic decays of heavy quarks, has been optimized using artificial neural networks whenever necessary, that is whenever the problem to solve implied taking into account simultaneously a large number of parameters. Our results are compatible with other LEP measurements and with the Standard Model predictions for a top quark of 174{+-}31 GeV/c{open_square} and a Higgs boson mass between 60 and 1000 GeV/c{open_square}. (author). 159 refs., 88 figs., 37 tabs.

  12. Search for heavy quarks decaying into a top quark and a W or Z boson using lepton + jets events in pp collisions at $\\sqrt{s}$ = 7 TeV

    CERN Document Server

    Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Staykova, Zlatka; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Marcken, Gil; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Verwilligen, Piet; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Karjalainen, Ahti; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel

    2013-01-01

    Results are presented from a search for the pair-production of heavy quarks, Q Q-bar, that decay exclusively into a top quark and a W or Z boson. The search is performed using a sample of proton-proton collisions at $\\sqrt{s}$ = 7 TeV corresponding to an integrated luminosity of 5.0 inverse femtobarns, collected by the Compact Muon Solenoid experiment. The signal region is defined using a sample of events containing one electron or muon, missing transverse momentum, and at least four jets with large transverse momenta, where one jet is likely to originate from the decay of a bottom quark. No significant excess of events is observed with respect to the standard model expectations. Assuming a strong pair-production mechanism, quark masses below 675 (625) GeV decaying into tW (tZ) are excluded at the 95% confidence level.

  13. A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations

    Science.gov (United States)

    Shimojo, Fuyuki; Hattori, Shinnosuke; Kalia, Rajiv K.; Kunaseth, Manaschai; Mou, Weiwei; Nakano, Aiichiro; Nomura, Ken-ichi; Ohmura, Satoshi; Rajak, Pankaj; Shimamura, Kohei; Vashishta, Priya

    2014-05-01

    We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786 432 cores for a 50.3 × 106-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16 661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques

  14. A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Shimojo, Fuyuki; Hattori, Shinnosuke [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Kalia, Rajiv K.; Mou, Weiwei; Nakano, Aiichiro; Nomura, Ken-ichi; Rajak, Pankaj; Vashishta, Priya [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Kunaseth, Manaschai [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); National Nanotechnology Center, Pathumthani 12120 (Thailand); Ohmura, Satoshi [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Shimamura, Kohei [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395 (Japan)

    2014-05-14

    We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786 432 cores for a 50.3 × 10{sup 6}-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16 661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of

  15. B -meson decay constants from 2+1 -flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Christ, N. H.; Flynn, J. M.; Izubuchi, T.; Kawanai, T.; Lehner, C.; Soni, A.; Van de Water, R. S.; Witzel, O.

    2015-03-01

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a0.11, 0.086 fm with unitary pion masses as light as Mπ290MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the

  16. Recombination dynamics in aerotaxy-grown Zn-doped GaAs nanowires

    Science.gov (United States)

    Zhang, Wei; Yang, Fangfang; Messing, Maria E.; Mergenthaler, Kilian; Pistol, Mats-Erik; Deppert, Knut; Samuelson, Lars; Magnusson, Martin H.; Yartsev, Arkady

    2016-11-01

    In this paper we have investigated the dynamics of photo-generated charge carriers in a series of aerotaxy-grown GaAs nanowires (NWs) with different levels of Zn doping. Time-resolved photo-induced luminescence and transient absorption have been employed to investigate radiative (band edge transition) and non-radiative charge recombination processes, respectively. We find that the photo-luminescence (PL) lifetime of intrinsic GaAs NWs is significantly increased after growing an AlGaAs shell over them, indicating that an AlGaAs shell can effectively passivate the surface of aerotaxy-grown GaAs NWs. We observe that PL decay time as well as PL intensity decrease with increasing Zn doping, which can be attributed to thermally activated electron trapping with the trap density increased due to the Zn doping level.

  17. Electronic fine structure and recombination dynamics in single InAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Seguin, R.

    2008-01-28

    In the work at hand single InAs/GaAs quantum dots (QDs) are examined via cathodoluminescence spectroscopy. A thorough analysis of the spectra leads to an unambiguous assignment of the lines to the decay of specific excitonic complexes. A special aspect of the Coulomb interaction, the exchange interaction, gives rise to a fine structure in the initial and final states of an excitonic decay. This leads to a fine structure in the emission spectra that again is unique for every excitonic complex. The exchange interaction is discussed in great detail in this work.QDs of different sizes are investigated and the influence on the electronic properties is monitored. Additionally, the structure is modified ex situ by a thermal annealing process. The changes of the spectra under different annealing temperatures are traced. Finally, recombination dynamics of different excitonic complexes are examined by performing time-resolved cathodoluminescence spectroscopy. (orig.)

  18. Evolutionary Dynamics and Temporal/Geographical Correlates of Recombination in the Human Enterovirus Echovirus Types 9, 11, and 30▿

    Science.gov (United States)

    McWilliam Leitch, E. C.; Cabrerizo, M.; Cardosa, J.; Harvala, H.; Ivanova, O. E.; Kroes, A. C. M.; Lukashev, A.; Muir, P.; Odoom, J.; Roivainen, M.; Susi, P.; Trallero, G.; Evans, D. J.; Simmonds, P.

    2010-01-01

    The relationship between virus evolution and recombination in species B human enteroviruses was investigated through large-scale genetic analysis of echovirus type 9 (E9) and E11 isolates (n = 85 and 116) from 16 European, African, and Asian countries between 1995 and 2008. Cluster 1 E9 isolates and genotype D5 and A E11 isolates showed evidence of frequent recombination between the VP1 and 3Dpol regions, the latter falling into 23 (E9) and 43 (E11) clades interspersed phylogenetically with 46 3Dpol clades of E30 and with those of other species B serotypes. Remarkably, only 2 of the 112 3Dpol clades were shared by more than one serotype (E11 and E30), demonstrating an extremely large and genetically heterogeneous recombination pool of species B nonstructural-region variants. The likelihood of recombination increased with geographical separation and time, and both were correlated with VP1 divergence, whose substitution rates allowed recombination half-lives of 1.3, 9.8, and 3.1 years, respectively, for E9, E11, and E30 to be calculated. These marked differences in recombination dynamics matched epidemiological patterns of periodic epidemic cycles of 2 to 3 (E9) and 5 to 6 (E30) years and the longer-term endemic pattern of E11 infections. Phylotemporal analysis using a Bayesian Markov chain Monte Carlo method, which placed recombination events within the evolutionary reconstruction of VP1, showed a close relationship with VP1 lineage expansion, with defined recombination events that correlated with their epidemiological periodicity. Whether recombination events contribute directly to changes in transmissibility that drive epidemic behavior or occur stochastically during periodic population bottlenecks is an unresolved issue vital to future understanding of enterovirus molecular epidemiology and pathogenesis. PMID:20610722

  19. Evolutionary dynamics and temporal/geographical correlates of recombination in the human enterovirus echovirus types 9, 11, and 30.

    Science.gov (United States)

    McWilliam Leitch, E C; Cabrerizo, M; Cardosa, J; Harvala, H; Ivanova, O E; Kroes, A C M; Lukashev, A; Muir, P; Odoom, J; Roivainen, M; Susi, P; Trallero, G; Evans, D J; Simmonds, P

    2010-09-01

    The relationship between virus evolution and recombination in species B human enteroviruses was investigated through large-scale genetic analysis of echovirus type 9 (E9) and E11 isolates (n = 85 and 116) from 16 European, African, and Asian countries between 1995 and 2008. Cluster 1 E9 isolates and genotype D5 and A E11 isolates showed evidence of frequent recombination between the VP1 and 3Dpol regions, the latter falling into 23 (E9) and 43 (E11) clades interspersed phylogenetically with 46 3Dpol clades of E30 and with those of other species B serotypes. Remarkably, only 2 of the 112 3Dpol clades were shared by more than one serotype (E11 and E30), demonstrating an extremely large and genetically heterogeneous recombination pool of species B nonstructural-region variants. The likelihood of recombination increased with geographical separation and time, and both were correlated with VP1 divergence, whose substitution rates allowed recombination half-lives of 1.3, 9.8, and 3.1 years, respectively, for E9, E11, and E30 to be calculated. These marked differences in recombination dynamics matched epidemiological patterns of periodic epidemic cycles of 2 to 3 (E9) and 5 to 6 (E30) years and the longer-term endemic pattern of E11 infections. Phylotemporal analysis using a Bayesian Markov chain Monte Carlo method, which placed recombination events within the evolutionary reconstruction of VP1, showed a close relationship with VP1 lineage expansion, with defined recombination events that correlated with their epidemiological periodicity. Whether recombination events contribute directly to changes in transmissibility that drive epidemic behavior or occur stochastically during periodic population bottlenecks is an unresolved issue vital to future understanding of enterovirus molecular epidemiology and pathogenesis.

  20. Photocarrier recombination dynamics in perovskite CH3NH3PbI3 for solar cell applications.

    Science.gov (United States)

    Yamada, Yasuhiro; Nakamura, Toru; Endo, Masaru; Wakamiya, Atsushi; Kanemitsu, Yoshihiko

    2014-08-20

    Using time-resolved photoluminescence and transient absorption measurements at room temperature, we report excitation-intensity-dependent photocarrier recombination processes in thin films made from the organo-metal halide perovskite semiconductor CH3NH3PbI3 for solar-cell applications. The photocarrier dynamics are well described by a simple rate equation including single-carrier trapping and electron-hole radiative recombination. This result provides clear evidence that the free-carrier model is better than the exciton model for interpreting the optical properties of CH3NH3PbI3. The observed large two-carrier recombination rate suggests the promising potential of perovskite semiconductors for optoelectronic device applications. Our findings provide the information about the dynamical behaviors of photoexcited carriers that is needed for developing high-efficiency perovskite solar cells.

  1. Charge transport and recombination dynamics in organic bulk heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Andreas

    2011-08-02

    The charge transport in disordered organic bulk heterojunction (BHJ) solar cells is a crucial process affecting the power conversion efficiency (PCE) of the solar cell. With the need of synthesizing new materials for improving the power conversion efficiency of those cells it is important to study not only the photophysical but also the electrical properties of the new material classes. Thereby, the experimental techniques need to be applicable to operating solar cells. In this work, the conventional methods of transient photoconductivity (also known as ''Time-of-Flight'' (TOF)), as well as the transient charge extraction technique of ''Charge Carrier Extraction by Linearly Increasing Voltage'' (CELIV) are performed on different organic blend compositions. Especially with the latter it is feasible to study the dynamics - i.e. charge transport and charge carrier recombination - in bulk heterojunction (BHJ) solar cells with active layer thicknesses of 100-200 nm. For a well performing organic BHJ solar cells the morphology is the most crucial parameter finding a trade-off between an efficient photogeneration of charge carriers and the transport of the latter to the electrodes. Besides the morphology, the nature of energetic disorder of the active material blend and its influence on the dynamics are discussed extensively in this work. Thereby, the material system of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C{sub 61}butyric acid methyl ester (PC{sub 61}BM) serves mainly as a reference material system. New promising donor or acceptor materials and their potential for application in organic photovoltaics are studied in view of charge dynamics and compared with the reference system. With the need for commercialization of organic solar cells the question of the impact of environmental conditions on the PCE of the solar cells raises. In this work, organic BHJ solar cells exposed to synthetic air for finite duration are

  2. Femtosecond dynamics of fundamental reaction processes in liquids: Proton transfer, geminate recombination, isomerization and vibrational relaxation. [Spiropyrans

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, B.J.

    1992-11-01

    The fast excited state intramolecular proton transfer of 3-hydroxyflavone is measured and effects of external hydrogen-bonding interactions on the proton transfer are studied. The proton transfer takes place in [approximately]240 fsec in nonpolar environments, but becomes faster than instrumental resolution of 110 fsec in methanol solution. The dynamics following photodissociation of CH[sub 2]I[sub 2] and other small molecules provide the first direct observations of geminate recombination. The recombination of many different photodissociating species occurs on a [approximately]350 fsec time scale. Results show that recombination yields but not rates depend on the solvent environment and suggest that recombination kinetics are dominated by a single collision with surrounding solvent cage. Studies of sterically locked phenyl-substituted butadienes offer new insights into the electronic structure and isomerization behavior of conjugated polyenes. Data show no simple correlation between hinderance of specific large amplitude motions and signatures of isomerizative behavior such as viscosity dependent excited state lifetimes, implying that the isomerization does not provide a suitable for simple condensed phase reaction rate theories. The spectral dynamics of a photochromic spiropyran indicate that recombination, isomerization and vibrational relaxation all play important roles in photoreactivity of complex molecules. The interplay of these microscopic phenomena and their effect on macroscopic properties such as photochromism are discussed. All the results indicate that the initial steps of the photochromic reaction process occur extremely rapidly. Laser system and computer codes for data analysis are discussed.

  3. Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity.

    Science.gov (United States)

    Guse, Joanna A; Jones, Timothy W; Danos, Andrew; McCamey, Dane R

    2017-03-06

    A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials such as organo-lead halide perovskites is presented. The perovskite film thickness and absorption coefficient are initially characterized by profilometry and UV-VIS absorption spectroscopy. Calibration of both laser power and cavity sensitivity is described in detail. A protocol for performing Flash-photolysis Time Resolved Microwave Conductivity (TRMC) experiments, a non-contact method of determining the conductivity of a material, is presented. A process for identifying the real and imaginary components of the complex conductivity by performing TRMC as a function of microwave frequency is given. Charge carrier dynamics are determined under different excitation regimes (including both power and wavelength). Techniques for distinguishing between direct and trap-mediated decay processes are presented and discussed. Results are modelled and interpreted with reference to a general kinetic model of photoinduced charge carriers in a semiconductor. The techniques described are applicable to a wide range of optoelectronic materials, including organic and inorganic photovoltaic materials, nanoparticles, and conducting/semiconducting thin films.

  4. Dynamic Solvent Effect on Ultrafast Charge Recombination Kinetics in Excited Donor-Acceptor Complexes.

    Science.gov (United States)

    Mikhailova, Tatyana V; Mikhailova, Valentina A; Ivanov, Anatoly I

    2016-11-23

    Manifestation of the dynamic solvent effect (DSE) on the charge recombination (CR) kinetics of photoexcited donor-acceptor complexes in polar solvents has been investigated within the framework of the multichannel stochastic model. The model takes into account the reorganization of both the solvent and a number of intramolecular high-frequency vibration modes as well as their relaxation. The non-Markovian solvent dynamics is described in terms of two relaxation modes. The similarities and differences inherent to ultrafast charge transfer reactions occurring in the nonequilibrium and thermal regimes have been identified. The most important differences are as follows: (1) the DSE is strong in the area of weak exergonicity and is weak in the area of strong exergonicity for thermal reactions, whereas for the nonequilibrium reactions, the regions of strong and weak DSEs are reversed; (2) an increase in the electronic coupling value results in a decrease in the magnitude of DSE for nonequilibrium electron transfer and in its increase for the thermal reactions; and (3) the two-staged regime most clearly manifests if the reorganization energy of the relaxation modes noticeably exceeds the CR free-energy gap. With an increase in electronic coupling, the kinetics approaches the exponential regime because in the limit of strong electronic coupling, the reaction includes only single, nonequilibrium, stage.

  5. Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d + Au collisions at √sNN = 200  GeV.

    Science.gov (United States)

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Castera, P; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Conesa Del Valle, Z; Connors, M; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Garishvili, I; Glenn, A; Gong, H; Gong, X; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grim, G; Grosse Perdekamp, M; Gunji, T; Guo, L; Gustafsson, H-Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harper, C; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D J; Kim, E-J; Kim, Y-J; Kim, Y K; Kinney, E; Kiss, A; Kistenev, E; Kleinjan, D; Kline, P; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Linden Levy, L A; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mitchell, J T; Miyachi, Y; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Park, W J; Pate, S F; Patel, L; Pei, H; Peng, J-C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sarsour, M; Sato, T; Savastio, M; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Seto, R; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Sodre, T; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M

    2014-06-27

    The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6  GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at √sNN = 200  GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.

  6. The B->pi l nu and Bs->K l nu form factors and |Vub| from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    CERN Document Server

    Flynn, J M; Kawanai, T; Lehner, C; Soni, A; Van de Water, R S; Witzel, O

    2015-01-01

    We calculate the form factors for B->pi l nu & Bs->K l nu decay in lattice QCD. We use the (2+1)-flavor RBC-UKQCD gauge field-ensembles generated with the domain-wall fermion and Iwasaki gauge actions. For the b quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation. We analyze data at 2 lattice spacings a~0.11, 0.086 fm with pion masses as light as M_pi~290 MeV. We extrapolate our numerical results to the physical light-quark masses and to the continuum and interpolate in the pion/kaon energy using SU(2) "hard-pion" chiral perturbation theory. We provide complete systematic error budgets for the vector & scalar form factors f+(q^2) & f0(q2) for B->pi l nu & Bs ->K l nu at 3 momenta that span the q^2 range accessible in our numerical simulations. Next we extrapolate these results to q^2 = 0 using a model-independent z-parameterization based on analyticity & unitarity. We present our final results for f+(q^2) & f0(q^2) as the z coefficients and matr...

  7. Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d+Au collisions at sqrt(s_NN)=200 GeV

    CERN Document Server

    Adare, A; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Castera, P; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; del Valle, Z Conesa; Connors, M; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Garishvili, I; Glenn, A; Gong, H; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Grim, G; Perdekamp, M Grosse; Gunji, T; Guo, L; Gustafsson, H -Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harper, C; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D J; Kim, E -J; Kim, Y -J; Kim, Y K; Kinney, E; Kiss, Á; Kistenev, E; Kleinjan, D; Kline, P; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Levy, L A Linden; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mitchell, J T; Miyachi, Y; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Park, W J; Pate, S F; Patel, L; Pei, H; Peng, J -C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sarsour, M; Sato, T; Savastio, M; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Seto, R; Sharma, D; Shein, I; Shibata, T -A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Sodre, T; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M

    2013-01-01

    The PHENIX experiment has measured open heavy-flavor production via semileptonic decay muons over the transverse momentum range 1 < pT < 6 GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p+p collisions at ?sNN = 200 GeV. In central d+Au collisions an enhancement (suppression) of heavy-flavor muon production is observed at backward (forward) rapidity relative to the yield in p+p collisions scaled by the number of binary collisions. Modification of the gluon density distribution in the Au nucleus contributes in terms of anti-shadowing enhancement and shadowing suppression; however, the enhancement seen at backward rapidity exceeds expectations from this effect alone. These results, implying an important role for additional cold nuclear matter effects, serves as a key baseline for heavy-quark measurements in A+A collisions and in constraining the magnitude of charmonia breakup effects at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

  8. Search for pair production of new heavy quarks that decay to a $\\mathbf{Z}$ boson and a third generation quark in $\\mathbf{pp}$ collisions at $\\mathbf{\\sqrt{s}=8}$ TeV with the ATLAS detector

    CERN Document Server

    The ATLAS collaboration

    2013-01-01

    A search is presented for the production of a new heavy quark with its antiparticle, assuming the new quark has a significant branching ratio to decay into a $Z$ boson and a third generation Standard Model quark. In the case of a new charge $+2/3$ quark ($T$) the decay targeted is $T \\rightarrow Zt$, while for a new charge $-1/3$ quark ($B$) the decay targeted is $B \\rightarrow Zb$. The search uses a dataset corresponding to $14.3~\\mathrm{fb}^{-1}$ of $pp$ collisions at $\\sqrt{s}=8$ TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Selected events contain a high transverse momentum $Z$ boson candidate reconstructed from a pair of oppositely charged electrons or muons. Additionally, the presence of at least two jets possessing properties consistent with the decay of a $b$ hadron is required, as well as large total transverse momentum of all central jets in the event. No significant excess of events above the Standard Model expectation is observed, and upper limits are derived for ...

  9. Ultrafast Dynamics of Hole Injection and Recombination in Organometal Halide Perovskite Using Nickel Oxide as p-Type Contact Electrode.

    Science.gov (United States)

    Corani, Alice; Li, Ming-Hsien; Shen, Po-Shen; Chen, Peter; Guo, Tzung-Fang; El Nahhas, Amal; Zheng, Kaibo; Yartsev, Arkady; Sundström, Villy; Ponseca, Carlito S

    2016-04-01

    There is a mounting effort to use nickel oxide (NiO) as p-type selective electrode for organometal halide perovskite-based solar cells. Recently, an overall power conversion efficiency using this hole acceptor has reached 18%. However, ultrafast spectroscopic investigations on the mechanism of charge injection as well as recombination dynamics have yet to be studied and understood. Using time-resolved terahertz spectroscopy, we show that hole transfer is complete on the subpicosecond time scale, driven by the favorable band alignment between the valence bands of perovskite and NiO nanoparticles (NiO(np)). Recombination time between holes injected into NiO(np) and mobile electrons in the perovskite material is shown to be hundreds of picoseconds to a few nanoseconds. Because of the low conductivity of NiO(np), holes are pinned at the interface, and it is electrons that determine the recombination rate. This recombination competes with charge collection and therefore must be minimized. Doping NiO to promote higher mobility of holes is desirable in order to prevent back recombination.

  10. Ultrafast Charge Recombination Dynamics in Ternary Electron Donor-Acceptor Complexes: (Benzene)2-Tetracyanoethylene Complexes.

    Science.gov (United States)

    Chiu, Chih-Chung; Hung, Chih-Chang; Cheng, Po-Yuan

    2016-12-08

    The charge-transfer (CT) state relaxation dynamics of the binary (1:1) and ternary (2:1) benzene/tetracyanoethylene (BZ/TCNE) complexes are reported. Steady-state and ultrafast time-resolved broadband fluorescence (TRFL) spectra of TCNE dissolved in a series of BZ/CCl4 mixed solvents are measured to elucidate the spectroscopic properties of the BZ/TCNE complexes and their CT-state relaxation dynamics. Both steady-state and TRFL spectra exhibit marked BZ concentration dependences, which can be attributed to the formation of two types of 2:1 complexes in the ground and excited states. By combining with the density functional theory (DFT) calculations, it was concluded that the BZ concentration dependence of the absorption spectra is mainly due to the formation and excitation of the sandwich-type 2:1 ternary complexes, whereas the changes in fluorescence spectra at high BZ concentrations are due to the formation of the asymmetric-type 2:1 ternary complex CT1 state. A unified mechanism involving both direct excitation and secondary formation of the 2:1 complexes CT states are proposed to account for the observations. The equilibrium charge recombination (CR) time constant of the 1:1 CT1 state is determined to be ∼150 ps in CCl4, whereas that of the 2:1 DDA-type CT1 state becomes ∼70 ps in 10% BZ/CCl4 and ∼34 ps in pure BZ. The CR rates and the CT1-S0 energy gap of these complexes in different solvents exhibit a correlation conforming to the Marcus inverted region. It is concluded that partial charge resonance occurring between the two adjacent BZs in the asymmetric-type 2:1 CT1-state reduces the CR reaction exothermicity and increases the CR rate.

  11. Nuclear dynamics of RAD52 group homologous recombination proteins in response to DNA damage.

    NARCIS (Netherlands)

    J. Essers (Jeroen); A.B. Houtsmuller (Adriaan); L.R. van Veelen (Lieneke); C. Paulusma (Coen); A.L. Nigg (Alex); A. Pastink (Albert); W. Vermeulen (Wim); J.H.J. Hoeijmakers (Jan); R. Kanaar (Roland)

    2002-01-01

    textabstractRecombination between homologous DNA molecules is essential for the proper maintenance and duplication of the genome, and for the repair of exogenously induced DNA damage such as double-strand breaks. Homologous recombination requires the RAD52 group proteins, including Rad51, Rad52 and

  12. Complex Langevin in Lattice QCD: dynamic stabilisation and the phase diagram

    CERN Document Server

    Aarts, Gert; Jäger, Benjamin; Sexty, Dénes

    2016-01-01

    Complex Langevin simulations provide an alternative to sample path integrals with complex weights and therefore are suited to determine the phase diagram of QCD from first principles. We use our proposed method of Dynamic Stabilisation (DS) to ensure improved convergence to the right limit and present new systematic tests of this technique. We also show results on QCD in the limit of heavy quarks and an analysis of DS compared to known results from reweighting.

  13. Ultrafast carrier dynamics and radiative recombination in multiferroic BiFeO3 single crystals and thin films

    Directory of Open Access Journals (Sweden)

    Taylor A. J.

    2013-03-01

    Full Text Available We report a detailed comparison of ultrafast carrier dynamics in single crystals and thin films of multiferroic BiFeO3 (BFO. Using degenerate femtosecond optical pump-probe spectroscopy, we find that the observed dynamics are qualitatively similar in both samples. After photoexcitation, electrons relax to the conduction band minimum through electron-phonon coupling, with subsequent carrier relaxation proceeding via various recombination pathways that extend to a nanosecond timescale. Subtle differences observed in our measurements indicate that BFO films have a higher band gap than single crystals. Overall, our results demonstrate that carrier relaxation in BFO is analogous to that in bulk semiconductors.

  14. The population and evolutionary dynamics of homologous gene recombination in bacterial populations.

    Directory of Open Access Journals (Sweden)

    Bruce R Levin

    2009-08-01

    Full Text Available In bacteria, recombination is a rare event, not a part of the reproductive process. Nevertheless, recombination -- broadly defined to include the acquisition of genes from external sources, i.e., horizontal gene transfer (HGT -- plays a central role as a source of variation for adaptive evolution in many species of bacteria. Much of niche expansion, resistance to antibiotics and other environmental stresses, virulence, and other characteristics that make bacteria interesting and problematic, is achieved through the expression of genes and genetic elements obtained from other populations of bacteria of the same and different species, as well as from eukaryotes and archaea. While recombination of homologous genes among members of the same species has played a central role in the development of the genetics and molecular biology of bacteria, the contribution of homologous gene recombination (HGR to bacterial evolution is not at all clear. Also, not so clear are the selective pressures responsible for the evolution and maintenance of transformation, the only bacteria-encoded form of HGR. Using a semi-stochastic simulation of mutation, recombination, and selection within bacterial populations and competition between populations, we explore (1 the contribution of HGR to the rate of adaptive evolution in these populations and (2 the conditions under which HGR will provide a bacterial population a selective advantage over non-recombining or more slowly recombining populations. The results of our simulation indicate that, under broad conditions: (1 HGR occurring at rates in the range anticipated for bacteria like Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, and Bacillus subtilis will accelerate the rate at which a population adapts to environmental conditions; (2 once established in a population, selection for this capacity to increase rates of adaptive evolution can maintain bacteria-encoded mechanisms of recombination and prevent

  15. Dynamic metabolomics differentiates between carbon and energy starvation in recombinant Saccharomyces cerevisiae fermenting xylose

    Directory of Open Access Journals (Sweden)

    Bergdahl Basti

    2012-05-01

    Full Text Available Abstract Background The concerted effects of changes in gene expression due to changes in the environment are ultimately reflected in the metabolome. Dynamics of metabolite concentrations under a certain condition can therefore give a description of the cellular state with a high degree of functional information. We used this potential to evaluate the metabolic status of two recombinant strains of Saccharomyces cerevisiae during anaerobic batch fermentation of a glucose/xylose mixture. Two isogenic strains were studied, differing only in the pathways used for xylose assimilation: the oxidoreductive pathway with xylose reductase (XR and xylitol dehydrogenase (XDH or the isomerization pathway with xylose isomerase (XI. The isogenic relationship between the two strains ascertains that the observed responses are a result of the particular xylose pathway and not due to unknown changes in regulatory systems. An increased understanding of the physiological state of these strains is important for further development of efficient pentose-utilizing strains for bioethanol production. Results Using LC-MS/MS we determined the dynamics in the concentrations of intracellular metabolites in central carbon metabolism, nine amino acids, the purine nucleotides and redox cofactors. The general response to the transition from glucose to xylose was increased concentrations of amino acids and TCA-cycle intermediates, and decreased concentrations of sugar phosphates and redox cofactors. The two strains investigated had significantly different uptake rates of xylose which led to an enhanced response in the XI-strain. Despite the difference in xylose uptake rate, the adenylate energy charge remained high and stable around 0.8 in both strains. In contrast to the adenylate pool, large changes were observed in the guanylate pool. Conclusions The low uptake of xylose by the XI-strain led to several distinguished responses: depletion of key metabolites in glycolysis and NADPH

  16. Charge recombination kinetics and protein dynamics in wild type and carotenoid-less bacterial reaction centers: studies in trehalose glasses.

    Science.gov (United States)

    Francia, Francesco; Malferrari, Marco; Sacquin-Mora, Sophie; Venturoli, Giovanni

    2009-07-30

    The coupling between electron transfer and protein dynamics has been investigated in reaction centers (RCs) from the wild type (wt) and the carotenoid-less strain R26 of the photosynthetic bacterium Rhodobacter sphaeroides. Recombination kinetics between the primary photoreduced quinone acceptor (QA-) and photoxidized donor (P+) have been analyzed at room temperature in RCs incorporated into glassy trehalose matrices of different water/sugar ratios. As previously found in R26 RCs, also in the wt RC, upon matrix dehydration, P+QA- recombination accelerates and becomes broadly distributed, reflecting the inhibition of protein relaxation from the dark-adapted to the light-adapted conformation and the hindrance of interconversion between conformational substates. While in wet trehalose matrices (down to approximately one water per trehalose molecule) P+QA- recombination kinetics are essentially coincident in wt and R26 RCs, more extensive dehydration leads to two-times faster and more distributed kinetics in the carotenoid-containing RC, indicating a stronger inhibition of the internal protein dynamics in the wt RC. Coarse-grained Brownian dynamics simulations performed on the two RC structures reveal a markedly larger flexibility of the R26 RC, showing that a rigid core of residues, close to the quinone acceptors, is specifically softened in the absence of the carotenoid. These experimental and computational results concur to indicate that removal of the carotenoid molecule has long-range effects on protein dynamics and that the structural/dynamical coupling between the protein and the glassy matrix depends strongly upon the local mechanical properties of the protein interior. The data also suggest that the conformational change stabilizing P+QA- is localized around the QA binding pocket.

  17. Charge-carrier relaxation dynamics in highly ordered poly( p -phenylene vinylene): Effects of carrier bimolecular recombination and trapping

    Science.gov (United States)

    Soci, Cesare; Moses, Daniel; Xu, Qing-Hua; Heeger, Alan J.

    2005-12-01

    We have studied the charge-carrier relaxation dynamics in highly ordered poly( p -phenylene vinylene) over a broad time range using fast (t>100ps) transient photoconductivity measurements. The carrier density was also monitored (t>100fs) by means of photoinduced absorption probed at the infrared active vibrational modes. We find that promptly upon charge-carrier photogeneration, the initial polaron dynamics is governed by bimolecular recombination, while later in the subnanosecond time regime carrier trapping gives rise to an exponential decay of the photocurrent. The more sensitive transient photocurrent measurements indicate that in the low excitation regime, when the density of photocarriers is comparable to that of the trapping states (˜1016cm-3) , carrier hopping between traps along with transport via extended states determines the carrier relaxation, a mechanism that is manifested by a long-lived photocurrent “tail.” This photocurrent tail is reduced by lowering the temperature and/or by increasing the excitation density. Based on these data, we develop a comprehensive kinetic model that takes into account the bipolar charge transport, the free-carrier bimolecular recombination, the carrier trapping, and the carrier recombination involving free and trapped carriers.

  18. Double-strand breaks in heterochromatin move outside of a dynamic HP1a domain to complete recombinational repair.

    Science.gov (United States)

    Chiolo, Irene; Minoda, Aki; Colmenares, Serafin U; Polyzos, Aris; Costes, Sylvain V; Karpen, Gary H

    2011-03-04

    Double-strand breaks (DSBs) in heterochromatic repetitive DNAs pose significant threats to genome integrity, but information about how such lesions are processed and repaired is sparse. We observe dramatic expansion and dynamic protrusions of the heterochromatin domain in response to ionizing radiation (IR) in Drosophila cells. We also find that heterochromatic DSBs are repaired by homologous recombination (HR) but with striking differences from euchromatin. Proteins involved in early HR events (resection) are rapidly recruited to DSBs within heterochromatin. In contrast, Rad51, which mediates strand invasion, only associates with DSBs that relocalize outside of the domain. Heterochromatin expansion and relocalization of foci require checkpoint and resection proteins. Finally, the Smc5/6 complex is enriched in heterochromatin and is required to exclude Rad51 from the domain and prevent abnormal recombination. We propose that the spatial and temporal control of DSB repair in heterochromatin safeguards genome stability by preventing aberrant exchanges between repeats.

  19. Controlling complex Langevin dynamics at finite density

    Energy Technology Data Exchange (ETDEWEB)

    Aarts, Gert; Bongiovanni, Lorenzo [Swansea University, Department of Physics, College of Science, Swansea (United Kingdom); Seiler, Erhard [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Muenchen (Germany); Sexty, Denes [Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); Stamatescu, Ion-Olimpiu [Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); FEST, Heidelberg (Germany)

    2013-07-15

    At nonzero chemical potential the numerical sign problem in lattice field theory limits the use of standard algorithms based on importance sampling. Complex Langevin dynamics provides a possible solution, but it has to be applied with care. In this review, we first summarise our current understanding of the approach, combining analytical and numerical insight. In the second part we study SL(N,C) gauge cooling, which was introduced recently as a tool to control complex Langevin dynamics in nonabelian gauge theories. We present new results in Polyakov chain models and in QCD with heavy quarks and compare various adaptive cooling implementations. (orig.)

  20. Tunable Optical Phenomena and Carrier Recombination Dynamics in III-V Semiconductor Nanostructures

    Science.gov (United States)

    Kumar Thota, Venkata Ramana

    . The results are presented in chapter 6. Finally, carrier recombination dynamics in rare-earth doped nanostructures are measured by using ultrafast spectroscopy. Carrier dynamics in InGaN:Yb 3+ nanowires and InGaN/GaN-Eu3+ superlattices are measured by frequency doubling the excitation laser, and the effects of implantation of rare-earth ions into the host material have been investigated. The results from the experimental measurements are presented in chapters 7 & 8. These experimental findings might help to understand the challenges associated with these nanostructured materials in the applications of quantum information processing, single photon emitters, and to integrate them into existing optoelectronic devices.

  1. Csm4, in collaboration with Ndj1, mediates telomere-led chromosome dynamics and recombination during yeast meiosis.

    Directory of Open Access Journals (Sweden)

    Jennifer J Wanat

    2008-09-01

    Full Text Available Chromosome movements are a general feature of mid-prophase of meiosis. In budding yeast, meiotic chromosomes exhibit dynamic movements, led by nuclear envelope (NE-associated telomeres, throughout the zygotene and pachytene stages. Zygotene motion underlies the global tendency for colocalization of NE-associated chromosome ends in a "bouquet." In this study, we identify Csm4 as a new molecular participant in these processes and show that, unlike the two previously identified components, Ndj1 and Mps3, Csm4 is not required for meiosis-specific telomere/NE association. Instead, it acts to couple telomere/NE ensembles to a force generation mechanism. Mutants lacking Csm4 and/or Ndj1 display the following closely related phenotypes: (i elevated crossover (CO frequencies and decreased CO interference without abrogation of normal pathways; (ii delayed progression of recombination, and recombination-coupled chromosome morphogenesis, with resulting delays in the MI division; and (iii nondisjunction of homologs at the MI division for some reason other than absence of (the obligatory CO(s. The recombination effects are discussed in the context of a model where the underlying defect is chromosome movement, the absence of which results in persistence of inappropriate chromosome relationships that, in turn, results in the observed mutant phenotypes.

  2. B -meson decay constants from 2+1 -flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Christ, N. H.; Flynn, J. M.; Izubuchi, T.; Kawanai, T.; Lehner, C.; Soni, A.; Van de Water, R. S.; Witzel, O.

    2015-03-01

    We calculate the B-meson decay constants fB, fBs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a0.11, 0.086 fm with unitary pion masses as light as Mπ290MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the

  3. Spatial emission distribution and carrier recombination dynamics in regularly arrayed InGaN/GaN quantum structure nanocolumns

    Science.gov (United States)

    Oto, Takao; Mizuno, Yutaro; Miyagawa, Rin; Kano, Tatsuya; Yoshida, Jun; Ema, Kazuhiro; Kishino, Katsumi

    2016-10-01

    Emission mechanisms in regularly arrayed InGaN/GaN quantum structures on GaN nanocolumns were investigated, focusing on the spatial emission distribution at the nanocolumn tops and the carrier recombination dynamics. The double-peak emission originated from the dot- and well-like InGaN areas with different In compositions was observed. From the results regarding the spatial emission distribution, we proposed a simple analytical approach to evaluating the carrier recombination dynamics using the rate equations based on the two energy states. The considerable six lifetimes can be uniquely determined from the experimental results. Carrier transfer from the high- to the low-energy state is dominant at high temperatures, producing the increased total emission efficiency of the inner low-energy area. In addition, the internal quantum efficiency should not be simply discussed using only the integrated intensity ratio between low and room temperatures because of the carrier transfer from high- to low-energy states.

  4. Dynamics and Predictive Potential of Antibodies against Insect-Derived Recombinant Leishmania infantum Proteins during Chemotherapy of Naturally Infected Dogs

    Science.gov (United States)

    Todolí, Felicitat; Galindo, Inmaculada; Gómez-Sebastián, Silvia; Pérez-Filgueira, Mariano; Escribano, José M.; Alberola, Jordi; Rodríguez-Cortés, Alhelí

    2010-01-01

    A predictive marker for the success treatment of canine leishmaniasis is required for the application of a more rational therapy protocol, which must improve the probability of cure and reduce Leishmania resistance to drugs. We investigated the dynamics and predictive value of antibodies against insect-derived recombinant L. infantum proteins rKMPII and rTRYP by using an enzyme-linked immunosorbent assay with retrospective serum samples from 36 dogs during treatment of canine leishmaniasis. In the entire group of dogs, concentrations of antibodies against rKMPII and rTRYP significantly decreased earlier than concentrations of antibodies against crude total Leishmania antigen (one versus six months), which suggested that the dynamics of antibodies against recombinant proteins may be useful for assessing clinical improvement after treatment. Interestingly, decreases in antibody concentrations against rKMPII occurred earlier in disease-free dogs than in dogs that remain clinically ill one year after beginning of treatment, which suggested that these antibodies may be useful for predicting disease-free survival one year after the beginning of therapy against canine leishmaniasis. PMID:20439957

  5. Carrier dynamics and recombination in GaN quantum discs embedded in AlGaN nanocolumns

    Energy Technology Data Exchange (ETDEWEB)

    Zamfirescu, M.; Abbarchi, M.; Gurioli, M.; Vinattieri, A. [INFM, Dept. of Physics and LENS, Universita di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Ristic, J.; Calleja, E. [Dept. Ingenieria Electronica, ETSI Telecomunicacion-ISOM, Universidad Politecnica, Ciudad Universitaria, Madrid 28040 (Spain)

    2005-02-01

    We report on the study of carrier dynamics and recombination by time resolved PL in GaN quantum discs embedded in Al{sub 0.16}Ga{sub 0.84}N nanocolumns, grown by MBE on AlN buffered Si (111) substrates. The emission band of GaN quantum discs and the Al{sub 0.16}Ga{sub 0.84}N nanocolumns are strongly overlapped and the standard analysis of PL decays is not useful to fully characterize the recombination kinetics. We make use of time resolved spectroscopy to clearly distinguish the different contributions to the PL spectra and therefore to obtain the intrinsic carrier time evolution in the quantum discs. We observe a dynamical red shift of the PL band together with a non exponential decay, very likely due to screening of the internal piezoelectric field provided by the photoinjected carriers. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Heavy-flavor dynamics in nucleus-nucleus collisions: from RHIC to LHC

    CERN Document Server

    Monteno, M; Beraudo, A; De Pace, A; Molinari, A; Nardi, M; Prino, F

    2011-01-01

    The stochastic dynamics of c and b quarks in the fireball created in nucleus-nucleus collisions at RHIC and LHC is studied employing a relativistic Langevin equation, based on a picture of multiple uncorrelated random collisions with the medium. Heavy-quark transport coefficients are evaluated within a pQCD approach, with a proper HTL resummation of medium effects for soft scatterings. The Langevin equation is embedded in a multi-step setup developed to study heavy-flavor observables in pp and AA collisions, starting from a NLO pQCD calculation of initial heavy-quark yields, complemented in the nuclear case by shadowing corrections, k_T-broadening and nuclear geometry effects. Then, only for AA collisions, the Langevin equation is solved numerically in a background medium described by relativistic hydrodynamics. Finally, the propagated heavy quarks are made hadronize and decay into electrons. Results for the nuclear modification factor R_AA of heavy-flavor hadrons and electrons from their semi-leptonic decays...

  7. Ultrafast and slow charge recombination dynamics of diketopyrrolopyrrole-NiO dye sensitized solar cells.

    Science.gov (United States)

    Zhang, Lei; Favereau, Ludovic; Farré, Yoann; Mijangos, Edgar; Pellegrin, Yann; Blart, Errol; Odobel, Fabrice; Hammarström, Leif

    2016-07-21

    In a photophysical study, two diketopyrrolopyrrole (DPP)-based sensitizers functionalized with 4-thiophenecarboxylic acid as an anchoring group and a bromo (DPPBr) or dicyanovinyl (DPPCN2) group, and a dyad consisting of a DPP unit linked to a naphthalenediimide group (DPP-NDI), were investigated both in solution and grafted on mesoporous NiO films. Femtosecond transient absorption measurements indicate that ultrafast hole injection occurred predominantly on a timescale of ∼200 fs, whereas the subsequent charge recombination occurred on a surprisingly wide range of timescales, from tens of ps to tens of μs; this kinetic heterogeneity is much greater than is typically observed for dye-sensitized TiO2 or ZnO. Also, in contrast to what is typically observed for dye-sensitized TiO2, there was no significant dependence on the excitation power of the recombination kinetics, which can be explained by the hole density being comparatively higher near the valence band of NiO before excitation. The additional acceptor group in DPP-NDI provided a rapid electron shift and stabilized charge separation up to the μs timescale. This enabled efficient (∼95%) regeneration of NDI by a Co(III)(dtb)3 electrolyte (dtb = 4,4'-di-tert-butyl-2,2'-bipyridine), according to transient absorption measurements. The regeneration of DPPBr and DPPCN2 by Co(III)(dtb)3 was instead inefficient, as most recombination for these dyes occurred on the sub-ns timescale. The transient spectroscopy data thus corroborated the trend of the published photovoltaic properties of dye-sensitized solar cells (DSSCs) based on these dyes on mesoporous NiO, and show the potential of a design strategy with a secondary acceptor bound to the dye. The study identifies rapid initial recombination between the dye and NiO as the main obstacle to obtaining high efficiencies in NiO-based DSSCs; these recombination components may be overlooked when studies are conducted using only methods with ns resolution or slower.

  8. Heavy quarks spectroscopy with the ATLAS detector

    CERN Document Server

    Dai, Tiesheng; The ATLAS collaboration

    2017-01-01

    A wide program of studies on heavy flavours is performed with the ATLAS detector. Production cross sections have been measured for hadrons with b and c quark, and for quarkonia states. The talk will discuss recent results on observation X(3872) state and its production rates including psi(2S), J/psi+J/psi prompt production (including the extraction of the double-parton-scattering component), and on the kinematical correlation in B hadron pair production, studied through their inclusive decays to J/psi and muons, respectively. Exotic states containing b and c quark have also been studies, and the talk will report on the searches for structures in the invariant mass of J/psi+hadron in the decay products of Lambda_b, and in the mass spectrum of Bc+ decays.

  9. Non-perturbative Heavy Quark Effective Theory

    DEFF Research Database (Denmark)

    Della Morte, Michele; Heitger, Jochen; Simma, Hubert;

    2015-01-01

    We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays...

  10. Non-perturbative Heavy Quark Effective Theory

    DEFF Research Database (Denmark)

    Della Morte, Michele; Heitger, Jochen; Simma, Hubert

    2015-01-01

    We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays...

  11. HEAVY QUARK POTENTIALS AND QUARKONIA BINDING.

    Energy Technology Data Exchange (ETDEWEB)

    PETRECZKY,P.

    2004-11-04

    The author reviews recent progress in studying in-medium modification of inter-quark forces at finite temperature in lattice QCD. Some applications to the problem of quarkonium binding in potential models is also discussed.

  12. Production and Hadronization of Heavy Quarks

    CERN Document Server

    Norrbin, E

    2000-01-01

    Heavy long-lived quarks, i.e. charm and bottom, are frequently studied both as tests of QCD and as probes for other physics aspects within and beyond the standard model. The long life-time implies that charm and bottom hadrons are formed and observed. This hadronization process cannot be studied in isolation, but depends on the production environment. Within the framework of the string model, a major effect is the drag from the other end of the string that the c/b quark belongs to. In extreme cases, a small-mass string can collapse to a single hadron, thereby giving a non-universal flavour composition to the produced hadrons. We here develop and present a detailed model for the charm/bottom hadronization process, involving the various aspects of string fragmentation and collapse, and put it in the context of several heavy-flavour production sources. Applications are presented from fixed-target to LHC energies.

  13. The QCD dynamics of tetraquark production

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lebed, Richard F. [Arizona State Univ., Tempe, AZ (United States)

    2015-06-18

    We use the twist dimensions of the operators underlying the dynamical behavior of exclusive production processes as a tool for determining the structure of exotic heavy-quark states such as the Z+c(4430) tetraquark. The resulting counting rules predict distinctive falloffs of the cross sections in center-of-mass energy, thus distinguishing whether the tetraquarks are segregated into di-meson molecules, diquark-antidiquark pairs, or more democratically arranged four-quark states. Additionally, we propose straightforward methods of experimentally producing additional exotic multiquark states.

  14. Recombination dynamics in heterostructures with two planar arrays of II-VI quantum dots

    Science.gov (United States)

    Mikhailov, T. N.; Belyaev, K. G.; Toropov, A. A.; Sorokin, S. V.; Pozina, G.; Shubina, T. V.

    2016-08-01

    We present time-resolved photoluminescence studies of epitaxial heterostructures with two arrays of Cd(Zn)Se/ZnSe quantum dots (QDs), which are formed by the successive insertion of CdSe fractional monolayers of different nominal thicknesses into a ZnSe matrix. Our data are suggestive of the appearance of effective channels of the energy transfer from the insertion comprising the array with smaller QDs, emitting at higher energy, towards the array with larger QDs, emitting at lower energy. The effect of dark excitons on characteristic times of radiative recombination is discussed.

  15. The influence of morphology on charge transport/recombination dynamics in planar perovskite solar cells

    Science.gov (United States)

    Yu, Man; Wang, Yi; Wang, Hao-Yi; Han, Jun; Qin, Yujun; Zhang, Jian-Ping; Ai, Xi-Cheng

    2016-10-01

    The photovoltaic performance of planar perovskite solar cell is significantly influenced by the morphology of perovskite film. In this work, five kinds of devices with different perovskite film morphologies were prepared by varying the concentration of CH3NH3Cl in precursor solutions. We found that best morphology of perovskite film results in the excellent photovoltaic performance with an average efficiency of 15.52% and a champion efficiency of 16.38%. Transient photovoltage and photocurrent measurements are performed to elucidate the mechanism of photoelectric conversion processes, which shows that the charge recombination is effectively suppressed and the charge transport is obviously promoted by optimized morphology.

  16. Effects of recombinant human insulin-like growth factor I on glomerular dynamics in the rat.

    OpenAIRE

    Hirschberg, R; Kopple, J D; Blantz, R C; Tucker, B J

    1991-01-01

    This study was undertaken to investigate the mechanisms by which an infusion of recombinant human insulin-like growth factor I (rhIGF-I) increases GFR and renal plasma flow (RPF) in rats. Glomerular micropuncture studies were carried out in 14 nonstarved Munich Wistar rats and in 12 rats deprived of food for 60-72 h. Animals were given an intravenous injection and infusion of either rhIGF-I or vehicle. In both nonstarved and starved animals, the IGF-I injection and infusion increased the seru...

  17. One-loop lattice artifacts of a dynamical charm quark

    Energy Technology Data Exchange (ETDEWEB)

    Athenodorou, Andreas; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2011-10-15

    For a few observables in O(a) improved lattice QCD, we compute discretization effects arising from the vacuum polarization of a heavy quark at one-loop order. In particular, the force between static quarks, the running coupling in the Schroedinger functional and a related quantity, anti {upsilon}, are considered. Results show that the cutoff effects of a dynamical charm quark are typically smaller than those present in the pure gauge theory. This perturbative result is a good indication that dynamical charm quarks are feasible already now. (orig.)

  18. Hydrophobic distal pocket affects NO-heme geminate recombination dynamics in dehaloperoxidase and H64V myoglobin.

    Science.gov (United States)

    Franzen, Stefan; Jasaitis, Audrius; Belyea, Jennifer; Brewer, Scott H; Casey, Robin; MacFarlane, Alexander W; Stanley, Robert J; Vos, Marten H; Martin, Jean-Louis

    2006-07-27

    The recombination dynamics of NO with dehaloperoxidase (DHP) from Amphitrite ornata following photolysis were measured by femtosecond time-resolved absorption spectroscopy. Singular value decomposition (SVD) analysis reveals two important basis spectra. The first SVD basis spectrum reports on the population of photolyzed NO molecules and has the appearance of the equilibrium difference spectrum between the deoxy and NO forms of DHP. The first basis time course has two kinetic components with time constants of tau(11) approximately 9 ps and tau(12) approximately 50 ps that correspond to geminate recombination. The fast geminate process tau(11) arises from a contact pair with the heme iron in a bound state with S = 3/2 spin. The slow geminate process tau(12) corresponds to the recombination from a more remote docking site >3 A from the heme iron with the greater barrier corresponding to a S = 5/2 spin state. The second SVD basis spectrum represents a time-dependent Soret band shift indicative of heme photophysical processes and protein relaxation with time constants of tau(21) approximately 3 ps and tau(22) approximately 17 ps, respectively. A comparison between the more rapid rate constant of the slow geminate phase in DHP-NO and horse heart myoglobin (HHMbNO) or sperm whale myoglobin (SWMbNO) suggests that protein interactions with photolyzed NO are weaker in DHP than in the wild-type MbNOs, consistent with the hydrophobic distal pocket of DHP. The slower protein relaxation rate tau(22) in DHP-NO relative to HHMbNO implies less effective trapping in the docking site of the distal pocket and is consistent with a greater yield for the fast geminate process. The trends observed for DHP-NO also hold for the H64V mutant of SWMb (H64V MbNO), consistent with a more hydrophobic distal pocket for that protein as well. We examine the influence of solution viscosity on NO recombination by varying the glycerol content in the range from 0% to 90% (v/v). The dominant effect of

  19. Mediator facilitates transcriptional activation and dynamic long-range contacts at the IgH locus during class switch recombination

    Science.gov (United States)

    Thomas-Claudepierre, Anne-Sophie; Robert, Isabelle; Rocha, Pedro P.; Raviram, Ramya; Schiavo, Ebe; Heyer, Vincent; Bonneau, Richard; Luo, Vincent M.; Reddy, Janardan K.; Borggrefe, Tilman; Skok, Jane A.

    2016-01-01

    Immunoglobulin (Ig) class switch recombination (CSR) is initiated by the transcription-coupled recruitment of activation-induced cytidine deaminase (AID) to Ig switch regions (S regions). During CSR, the IgH locus undergoes dynamic three-dimensional structural changes in which promoters, enhancers, and S regions are brought to close proximity. Nevertheless, little is known about the underlying mechanisms. In this study, we show that Med1 and Med12, two subunits of the mediator complex implicated in transcription initiation and long-range enhancer/promoter loop formation, are dynamically recruited to the IgH locus enhancers and the acceptor regions during CSR and that their knockdown in CH12 cells results in impaired CSR. Furthermore, we show that conditional inactivation of Med1 in B cells results in defective CSR and reduced acceptor S region transcription. Finally, we show that in B cells undergoing CSR, the dynamic long-range contacts between the IgH enhancers and the acceptor regions correlate with Med1 and Med12 binding and that they happen at a reduced frequency in Med1-deficient B cells. Our results implicate the mediator complex in the mechanism of CSR and are consistent with a model in which mediator facilitates the long-range contacts between S regions and the IgH locus enhancers during CSR and their transcriptional activation. PMID:26903242

  20. Mediator facilitates transcriptional activation and dynamic long-range contacts at the IgH locus during class switch recombination.

    Science.gov (United States)

    Thomas-Claudepierre, Anne-Sophie; Robert, Isabelle; Rocha, Pedro P; Raviram, Ramya; Schiavo, Ebe; Heyer, Vincent; Bonneau, Richard; Luo, Vincent M; Reddy, Janardan K; Borggrefe, Tilman; Skok, Jane A; Reina-San-Martin, Bernardo

    2016-03-07

    Immunoglobulin (Ig) class switch recombination (CSR) is initiated by the transcription-coupled recruitment of activation-induced cytidine deaminase (AID) to Ig switch regions (S regions). During CSR, the IgH locus undergoes dynamic three-dimensional structural changes in which promoters, enhancers, and S regions are brought to close proximity. Nevertheless, little is known about the underlying mechanisms. In this study, we show that Med1 and Med12, two subunits of the mediator complex implicated in transcription initiation and long-range enhancer/promoter loop formation, are dynamically recruited to the IgH locus enhancers and the acceptor regions during CSR and that their knockdown in CH12 cells results in impaired CSR. Furthermore, we show that conditional inactivation of Med1 in B cells results in defective CSR and reduced acceptor S region transcription. Finally, we show that in B cells undergoing CSR, the dynamic long-range contacts between the IgH enhancers and the acceptor regions correlate with Med1 and Med12 binding and that they happen at a reduced frequency in Med1-deficient B cells. Our results implicate the mediator complex in the mechanism of CSR and are consistent with a model in which mediator facilitates the long-range contacts between S regions and the IgH locus enhancers during CSR and their transcriptional activation.

  1. The heavy-quark forward-backward asymmetry to order {alpha}{sup 2}{sub s}; Die Vorwaerts-Rueckwaerts-Asymmetrie fuer schwere Quarks zur Ordnung {alpha}{sup 2}{sub s}

    Energy Technology Data Exchange (ETDEWEB)

    Waninger, Karl Constantin

    2011-02-28

    The goal of this thesis was the computation of the forward-backward asymmetry in the e{sup +}e{sup -}-production of heavy quarks to next-to-next-to-leading order in QCD (NNLO-QCD). Final states comprising up to four partons contribute to the corrections of order {alpha}{sup 2}{sub s}. The two-parton contributions are known for a while. The novel part is the computation of the three- and four-parton contributions. One main task of these computation was to explicitly show the cancellation of the infrared singularities arising in many of the contributing expressions. The other task was to ensure a stable numerical evaluation of the forward-backward asymmetry. The ultraviolet-divergences of the one loop integrals in the three-parton contributions are removed using renormalized perturbation theory. The infrared-divergence in the the three-parton final state contribution to the symmetric and antisymmetric cross sections cancels when building the forward-backward asymmetry out of these cross sections. This has been shown explicitly in this thesis by performing a Laurent-expansion of the relevant differential cross sections around the singular point in phase space. The infrared-divergences in the second-order three-parton contribution to the forward-backward asymmetry arising in the loop integrals, which are regularized in d = 4 - 2{epsilon} dimensions are quantified by {epsilon}-poles of up to second order and proportional to the leading-order contribution to the observable. The symmetric and antisymmetric contributions to the four-parton final state exhibit one-parton and two-parton unresolved infrared-singularities. In this thesis a modified version of the dipole subtraction formalism has been used to show that the one-parton-unresolved singularities of the four-parton final state cancel the infrared-singularities in the loop integrals of the contributions from the three-parton final states. Identifying the points in the four-parton phase space corresponding to the two

  2. Dynamics of photoexcited carrier relaxation and recombination in CdTe/CdS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Levi, D.H.; Fluegel, B.D.; Ahrenkiel, R.K. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    Efficiency-limiting defects in photovoltaic devices are readily probed by time-resolved spectroscopy. This paper presents the first direct optical measurements of the relaxation and recombination pathways of photoexcited carriers in the CdS window layer of CdTe/CdS polycrystalline thin films. Femtosecond time-resolved pump/probe measurements indicate the possible existence of a two-phase CdS/CdSTe layer, rather than a continuously graded alloy layer at the CdTe/CdS interface. Complementary time-resolved photoluminescence (PL) measurements show that the photoexcited carriers are rapidly captured by deep-level defects. The temporal and density-dependent properties of the photoluminescence prove that the large Stokes shift of the PL relative to the band edge is due to strong phonon coupling to deep-level defects in CdS. The authors suggest that modifications in the CdS processing may enhance carrier collection efficiency in the blue spectral region.

  3. Charge Recombination, Transport Dynamics, and Interfacial Effects in Organic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Heeger, Alan [Univ. of California, Santa Barbara, CA (United States); Bazan, Guillermo [Univ. of California, Santa Barbara, CA (United States); Nguyen, Thuc-Quyen [Univ. of California, Santa Barbara, CA (United States); Wudl, Fred [Univ. of California, Santa Barbara, CA (United States)

    2015-02-12

    The need for renewable sources of energy is well known. Conversion of sunlight to electricity using solar cells is one of the most important opportunities for creating renewable energy sources. The research carried out under DE-FG02-08ER46535 focused on the science and technology of “Plastic” solar cells comprised of organic (i.e. carbon based) semiconductors. The Bulk Heterojunction concept involves a phase separated blend of two organic semiconductors each with dimensions in the nano-meter length scale --- one a material that functions as a donor for electrons and the other a material that functions as an acceptor for electrons. The nano-scale inter-penetrating network concept for “Plastic” solar cells was created at UC Santa Barbara. A simple measure of the impact of this concept can be obtained from a Google search which gives 244,000 “hits” for the Bulk Heterojunction solar cell. Research funded through this program focused on four major areas: 1. Interfacial effects in organic photovoltaics, 2. Charge transfer and photogeneration of mobile charge carriers in organic photovoltaics, 3. Transport and recombination of the photogenerated charge carriers in organic photovoltaics, 4. Synthesis of novel organic semiconducting polymers and semiconducting small molecules, including conjugated polyelectrolytes. Following the discovery of ultrafast charge transfer at UC Santa Barbara in 1992, the nano-organic (Bulk Heterojunction) concept was formulated. The need for a morphology comprising two interpenetrating bicontinuous networks was clear: one network to carry the photogenerated electrons (negative charge) to the cathode and one network to carry the photo-generated holes (positive charge) to the anode. This remarkable self-assembled network morphology has now been established using Transmission electron Microscopy (TEM) either in the Phase Contrast mode or via TEM-Tomography. The steps involved in delivering power from a solar cell to an external circuit

  4. Charge Recombination, Transport Dynamics, and Interfacial Effects in Organic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Heeger, Alan; Bazan, Guillermo; Nguyen, Thuc-Quyen; Wudl, Fred

    2015-02-27

    The need for renewable sources of energy is well known. Conversion of sunlight to electricity using solar cells is one of the most important opportunities for creating renewable energy sources. The research carried out under DE-FG02-08ER46535 focused on the science and technology of “Plastic” solar cells comprised of organic (i.e. carbon based) semiconductors. The Bulk Heterojunction concept involves a phase separated blend of two organic semiconductors each with dimensions in the nano-meter length scale --- one a material that functions as a donor for electrons and the other a material that functions as an acceptor for electrons. The nano-scale inter-penetrating network concept for “Plastic” solar cells was created at UC Santa Barbara. A simple measure of the impact of this concept can be obtained from a Google search which gives 244,000 “hits” for the Bulk Heterojunction solar cell. Research funded through this program focused on four major areas: 1. Interfacial effects in organic photovoltaics, 2. Charge transfer and photogeneration of mobile charge carriers in organic photovoltaics, 3. Transport and recombination of the photogenerated charge carriers in organic photovoltaics, 4. Synthesis of novel organic semiconducting polymers and semiconducting small molecules, including conjugated polyelectrolytes. Following the discovery of ultrafast charge transfer at UC Santa Barbara in 1992, the nano-organic (Bulk Heterojunction) concept was formulated. The need for a morphology comprising two interpenetrating bicontinuous networks was clear: one network to carry the photogenerated electrons (negative charge) to the cathode and one network to carry the photo-generated holes (positive charge) to the anode. This remarkable self-assembled network morphology has now been established using Transmission electron Microscopy (TEM) either in the Phase Contrast mode or via TEM-Tomography. The steps involved in delivering power from a solar cell to an external circuit

  5. Impact of Reabsorption on the Emission Spectra and Recombination Dynamics of Hybrid Perovskite Single Crystals.

    Science.gov (United States)

    Diab, Hiba; Arnold, Christophe; Lédée, Ferdinand; Trippé-Allard, Gaëlle; Delport, Géraud; Vilar, Christèle; Bretenaker, Fabien; Barjon, Julien; Lauret, Jean-Sébastien; Deleporte, Emmanuelle; Garrot, Damien

    2017-07-06

    Understanding the surface properties of organic-inorganic lead-based perovskites is of high importance to improve the device's performance. Here, we have investigated the differences between surface and bulk optical properties of CH3NH3PbBr3 single crystals. Depth-resolved cathodoluminescence was used to probe the near-surface region on a depth of a few microns. In addition, we have studied the transmitted luminescence through thicknesses between 50 and 600 μm. In both experiments, the expected spectral shift due to the reabsorption effect has been precisely calculated. We demonstrate that reabsorption explains the important variations reported for the emission energy of single crystals. Single crystals are partially transparent to their own luminescence, and radiative transport is the dominant mechanism for propagation of the excitation in thick crystals. The transmitted luminescence dynamics are characterized by a long rise time and a lengthening of their decay due to photon recycling and light trapping.

  6. Decay constants of B-mesons from non-perturbative HQET with two light dynamical quarks

    DEFF Research Database (Denmark)

    Bernardoni, F.; Blossier, B.; Bulava, J.;

    2014-01-01

    We present a computation of B-meson decay constants from lattice QCD simulations within the framework of Heavy Quark Effective Theory for the b-quark. The next-to-leading order corrections in the HQET expansion are included non-perturbatively. Based on Nf=2 gauge field ensembles, covering three...... limits. Our final results read fB=186(13)MeV, fBs=224(14)MeV and fBs/fB=1.203(65). A comparison with other results in the literature does not reveal a dependence on the number of dynamical quarks, and effects from truncating HQET appear to be negligible....

  7. Recombination dynamics as a key determinant of open circuit voltage in organic bulk heterojunction solar cells: a comparison of four different donor polymers

    Energy Technology Data Exchange (ETDEWEB)

    Maurano, Andrea; Hamilton, Rick; Shuttle, Chris G.; O' Regan, Brian; Zhang, Weimin; McCulloch, Iain; Durrant, James R. [Departments of Chemistry, Imperial College London, South Kensington SW7 2AZ (United Kingdom); Ballantyne, Amy M.; Nelson, Jenny [Departments of Physics, Imperial College London, South Kensington SW7 2AZ (United Kingdom); Azimi, Hamed [Konarka Austria, Altenbergerstrasse 69, A-4040 Linz (Austria); Christian Doppler Laboratory for Surface Optics, Johannes Kepler University, Linz (Austria); Morana, Mauro; Brabec, Christoph J. [Konarka Austria, Altenbergerstrasse 69, A-4040 Linz (Austria)

    2010-11-24

    Transient photovoltage and charge extraction analyses are employed to analyzes charge carrier densities and bimolecular recombination dynamics in organic polymer: fullerene solar cells under open circuit operating conditions, employing four different donor polymers. An equation is derived which allows us to calculate the device V{sub OC} from these kinetic measurements. This equation allows us to calculate voltage output of devices within {+-} 25 meV of directly measured values. This analysis thus allows us to relate device open circuit voltage directly to the kinetics of bimolecular recombination, and thereby the influence of nanomorphology upon device voltage output. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Conservation of recombination hotspots in yeast

    OpenAIRE

    Tsai, Isheng J.; Burt, Austin; Koufopanou, Vassiliki

    2010-01-01

    Meiotic recombination does not occur randomly along a chromosome, but instead tends to be concentrated in small regions, known as “recombination hotspots.” Recombination hotspots are thought to be short-lived in evolutionary time due to their self-destructive nature, as gene conversion favors recombination-suppressing alleles over recombination-promoting alleles during double-strand repair. Consistent with this expectation, hotspots in humans are highly dynamic, with little correspondence in ...

  9. Heavy Dynamical Fermions in Lattice QCD

    CERN Document Server

    Hasenfratz, Anna; Hasenfratz, Anna; Grand, Thomas A. De

    1994-01-01

    It is expected that the only effect of heavy dynamical fermions in QCD is to renormalize the gauge coupling. We derive a simple expression for the shift in the gauge coupling induced by $N_f$ flavors of heavy fermions. We compare this formula to the shift in the gauge coupling at which the confinement-deconfinement phase transition occurs (at fixed lattice size) from numerical simulations as a function of quark mass and $N_f$. We find remarkable agreement with our expression down to a fairly light quark mass. However, simulations with eight heavy flavors and two light flavors show that the eight flavors do more than just shift the gauge coupling. We observe confinement-deconfinement transitions at $\\beta=0$ induced by a large number of heavy quarks. We comment on the relevance of our results to contemporary simulations of QCD which include dynamical fermions.

  10. Dynamical Effects on Jet Energy Loss in QCD Medium

    CERN Document Server

    Djordjevic, Magdalena

    2009-01-01

    Computation of radiative energy loss in a finite size dynamically screened QCD medium is a key ingredient for obtaining reliable predictions for jet quenching in ultra-relativistic heavy ion collisions. We develop a theory which allows calculating, to first order in the number of scattering centers, the energy loss of a heavy quark traveling through a finite size dynamical QCD medium. We show that the result for a dynamical medium is significantly larger compared to a medium consisting of randomly distributed static scattering centers. Therefore, a quantitative description of jet suppression at RHIC and LHC experiments must correctly account for the dynamics of the medium's constituents. Furthermore, qualitative predictions that come from this energy loss formalism are also presented.

  11. Tuning optical absorption and photoexcited recombination dynamics in La1-xSrxFeO3-δ through A-site substitution and oxygen vacancies

    Science.gov (United States)

    Smolin, Sergey; Scafetta, Mark; Choquette, Amber; Sfeir, Matthew; Baxter, Jason; May, Steven

    We study optical absorption and recombination dynamics in La1-xSrxFeO3-δ thin films, uncovering the effects of tuning nominal Fe valence via A-site substitution and oxygen stoichiometry. Variable angle spectroscopic ellipsometry was used to measure static optical properties, revealing a linear increase in absorption coefficient at 1.25 eV and a red-shifting of the optical absorption edge with increasing Sr fraction. The absorption spectra can be similarly tuned through the introduction of oxygen vacancies, indicating the critical role that nominal Fe valence plays in optical absorption. Dynamic optoelectronic properties were studied with ultrafast transient reflectance spectroscopy, revealing similar nanosecond photoexcited carrier lifetimes for oxygen deficient and stoichiometric films with the same nominal Fe valence. These results demonstrate that while the static optical absorption is strongly dependent on Fe valence tuned through cation or anion stoichiometry, oxygen vacancies do not appear to play a significantly detrimental role in the recombination kinetics. Nsf: ECCS-1201957, MRI DMR-0922929, MRI DMR-1040166. This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704.

  12. Recombination instability

    DEFF Research Database (Denmark)

    D'Angelo, N.

    1967-01-01

    A recombination instability is considered which may arise in a plasma if the temperature dependence of the volume recombination coefficient, alpha, is sufficiently strong. Two cases are analyzed: (a) a steady-state plasma produced in a neutral gas by X-rays or high energy electrons; and (b) an af...

  13. Cell biology of mitotic recombination

    DEFF Research Database (Denmark)

    Lisby, Michael; Rothstein, Rodney

    2015-01-01

    Homologous recombination provides high-fidelity DNA repair throughout all domains of life. Live cell fluorescence microscopy offers the opportunity to image individual recombination events in real time providing insight into the in vivo biochemistry of the involved proteins and DNA molecules...... of this review include the stoichiometry and dynamics of recombination complexes in vivo, the choreography of assembly and disassembly of recombination proteins at sites of DNA damage, the mobilization of damaged DNA during homology search, and the functional compartmentalization of the nucleus with respect...... as well as the cellular organization of the process of homologous recombination. Herein we review the cell biological aspects of mitotic homologous recombination with a focus on Saccharomyces cerevisiae and mammalian cells, but will also draw on findings from other experimental systems. Key topics...

  14. Recombination monitor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-02-03

    This is a brief report on LEReC recombination monitor design considerations. The recombination produced Au78+ ion rate is reviewed. Based on this two designs are discussed. One is to use the large dispersion lattice. It is shown that even with the large separation of the Au78+ beam from the Au79+ beam, the continued monitoring of the recombination is not possible. Accumulation of Au78+ ions is needed, plus collimation of the Au79+ beam. In another design, it is shown that the recombination monitor can be built based on the proposed scheme with the nominal lattice. From machine operation point of view, this design is preferable. Finally, possible studies and the alternative strategies with the basic goal of the monitor are discussed.

  15. Search for pair production of a new heavy quark that decays into a W boson and a light quark in pp collisions at s=8TeV with the ATLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bieniek, S. P.; Biesuz, N. V.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J. -B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bruscino, N.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cantrill, R.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Castaneda-Miranda, E.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B. C.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chau, C. C.; Chavez Barajas, C. A.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Colasurdo, L.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cúth, J.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D’Auria, S.; D’Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Benedetti, A.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell’Acqua, A.; Dell’Asta, L.; Dell’Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fayard, L.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. 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    2015-12-22

    We present a search for pair production of a new heavy quark ( Q ) that decays into a W boson and a light quark (q) in the final state where one W boson decays leptonically (to an electron or muon plus a neutrino) and the other W boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb-1 of pp collisions at $\\sqrt{s}$ = 8 TeV collected by the ATLAS detector at the LHC. No evidence of $Q\\overline{Q}$ production is observed. New chiral quarks with masses below 690 GeV are excluded at 95% confidence level, assuming BR ( Q → W q ) = 1 . Results are also interpreted in the context of vectorlike quark models, resulting in the limits on the mass of a vectorlike quark in the two-dimensional plane of BR ( Q → W q ) versus BR ( Q → H q ) .

  16. Sequential and simultaneous statistical optimization by dynamic design of experiment for peptide overexpression in recombinant Escherichia coli.

    Science.gov (United States)

    Lee, Kwang-Min; Rhee, Chang-Hoon; Kang, Choong-Kyung; Kim, Jung-Hoe

    2006-10-01

    The production of recombinant anti-HIV peptide, T-20, in Escherichia coli was optimized by statistical experimental designs (successive designs with multifactors) such as 2(4-1) fractional factorial, 2(3) full factorial, and 2(2) rotational central composite design in order. The effects of media compositions (glucose, NPK sources, MgSO4, and trace elements), induction level, induction timing (optical density at induction process), and induction duration (culture time after induction) on T-20 production were studied by using a statistical response surface method. A series of iterative experimental designs was employed to determine optimal fermentation conditions (media and process factors). Optimal ranges characterized by %T-20 (proportion of peptide to the total cell protein) were observed, narrowed down, and further investigated to determine the optimal combination of culture conditions, which was as follows: 9, 6, 10, and 1 mL of glucose, NPK sources, MgSO4, and trace elements, respectively, in a total of 100 mL of medium inducted at an OD of 0.55-0.75 with 0.7 mM isopropyl-beta-D-thiogalactopyranoside in an induction duration of 4 h. Under these conditions, up to 14% of T-20 was obtained. This statistical optimization allowed the production of T-20 to be increased more than twofold (from 6 to 14%) within a shorter induction duration (from 6 to 4 h) at the shake-flask scale.

  17. Bimolecular recombination in organic photovoltaics.

    Science.gov (United States)

    Lakhwani, Girish; Rao, Akshay; Friend, Richard H

    2014-01-01

    The recombination of electrons and holes is a major loss mechanism in photovoltaic devices that controls their performance. We review scientific literature on bimolecular recombination (BR) in bulk heterojunction organic photovoltaic devices to bring forward existing ideas on the origin and nature of BR and highlight both experimental and theoretical work done to quantify its extent. For these systems, Langevin theory fails to explain BR, and recombination dynamics turns out to be dependent on mobility, temperature, electric field, charge carrier concentration, and trapped charges. Relationships among the photocurrent, open-circuit voltage, fill factor, and morphology are discussed. Finally, we highlight the recent emergence of a molecular-level picture of recombination, taking into account the spin and delocalization of charges. Together with the macroscopic picture of recombination, these new insights allow for a comprehensive understanding of BR and provide design principles for future materials and devices.

  18. XRCC3 ATPase activity is required for normal XRCC3-Rad51C complex dynamics and homologous recombination

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, N; Hinz, J; Kopf, V L; Segalle, K; Thompson, L

    2004-02-25

    Homologous recombinational repair is a major DNA repair pathway that preserves chromosomal integrity by removing double-strand breaks, crosslinks, and other DNA damage. In eukaryotic cells, the Rad51 paralogs (XRCC2, XRCC3, Rad51B, Rad51C, and Rad51D) are involved in this process, although their exact functions are largely undetermined. All five paralogs contain ATPase motifs, and XRCC3 appears to exist in a single complex with Rad51C. To begin to examine the function of this Rad51C-XRCC3 complex, we generated mammalian expression vectors that produce human wild-type XRCC3 or mutant XRCC3 with either a non-conservative mutation (K113A) or a conservative mutation (K113R) in the GKT Walker A box of the ATPase motif. The three vectors were independently transfected into Xrcc3-deficient irs1SF CHO cells. Wild-type XRCC3 complemented irs1SF cells, albeit to varying degrees, while ATPase mutants had no complementing activity, even when the mutant protein was expressed at comparable levels to that in wild-type-complemented clones. Because of the mutants' dysfunction, we propose that ATP binding and hydrolyzing activities of XRCC3 are essential. We tested in vitro complex formation by wild-type and mutant XRCC3 with His6-tagged Rad51C upon coexpression in bacteria, nickel affinity purification, and western blotting. Wild-type and K113A mutant XRCC3 formed stable complexes with Rad51C and co-purified with Rad51C, while the K113R mutant did not and was predominantly insoluble. Addition of 5 mM ATP, but not ADP, also abolished complex formation by the wild-type proteins. These results suggest that XRCC3 is likely to regulate the dissociation and formation of Rad51C-XRCC3 complex through ATP binding and hydrolysis, with both processes being essential for the complex's ability to participate in HRR.

  19. Excision dynamics of Vibrio pathogenicity island-2 from Vibrio cholerae: role of a recombination directionality factor VefA

    Directory of Open Access Journals (Sweden)

    Napolitano Michael G

    2010-11-01

    Full Text Available Abstract Background Vibrio Pathogenicity Island-2 (VPI-2 is a 57 kb region present in choleragenic V. cholerae isolates that is required for growth on sialic acid as a sole carbon source. V. cholerae non-O1/O139 pathogenic strains also contain VPI-2, which in addition to sialic acid catabolism genes also encodes a type 3 secretion system in these strains. VPI-2 integrates into chromosome 1 at a tRNA-serine site and encodes an integrase intV2 (VC1758 that belongs to the tyrosine recombinase family. IntV2 is required for VPI-2 excision from chromosome 1, which occurs at very low levels, and formation of a non-replicative circular intermediate. Results We determined the conditions and the factors that affect excision of VPI-2 in V. cholerae N16961. We demonstrate that excision from chromosome 1 is induced at low temperature and after sublethal UV-light irradiation treatment. In addition, after UV-light irradiation compared to untreated cells, cells showed increased expression of three genes, intV2 (VC1758, and two putative recombination directionality factors (RDFs, vefA (VC1785 and vefB (VC1809 encoded within VPI-2. We demonstrate that along with IntV2, the RDF VefA is essential for excision. We constructed a knockout mutant of vefA in V. cholerae N16961, and found that no excision of VPI-2 occurred, indicating that a functional vefA gene is required for excision. Deletion of the second RDF encoded by vefB did not result in a loss of excision. Among Vibrio species in the genome database, we identified 27 putative RDFs within regions that also encoded IntV2 homologues. Within each species the RDFs and their cognate IntV2 proteins were associated with different island regions suggesting that this pairing is widespread. Conclusions We demonstrate that excision of VPI-2 is induced under some environmental stress conditions and we show for the first time that an RDF encoded within a pathogenicity island in V. cholerae is required for excision of the

  20. MRI Dynamically Evaluates the Therapeutic Effect of Recombinant Human MANF on Ischemia/Reperfusion Injury in Rats

    Directory of Open Access Journals (Sweden)

    Xian-Yun Wang

    2016-09-01

    Full Text Available As an endoplasmic reticulum (ER stress-inducible protein, mesencephalic astrocyte-derived neurotrophic factor (MANF has been proven to protect dopaminergic neurons and nondopaminergic cells. Our previous studies had shown that MANF protected against ischemia/reperfusion injury. Here, we developed a magnetic resonance imaging (MRI technology to dynamically evaluate the therapeutic effects of MANF on ischemia/reperfusion injury. We established a rat focal ischemic model by using middle cerebral artery occlusion (MCAO. MRI was performed to investigate the dynamics of lesion formation. MANF protein was injected into the right lateral ventricle at 3 h after reperfusion following MCAO for 90 min, when the obvious lesion firstly appeared according to MRI investigation. T2-weighted imaging for evaluating the therapeutic effects of MANF protein was performed in ischemia/reperfusion injury rats on Days 1, 2, 3, 5, and 7 post-reperfusion combined with histology methods. The results indicated that the administration of MANF protein at the early stage after ischemia/reperfusion injury decreased the mortality, improved the neurological function, reduced the cerebral infarct volume, and alleviated the brain tissue injury. The findings collected from MRI are consistent with the morphological and pathological changes, which suggest that MRI is a useful technology for evaluating the therapeutic effects of drugs.

  1. Recombination dynamics of type-II excitons in (Ga,In)As/GaAs/Ga(As,Sb) heterostructures

    Science.gov (United States)

    Gies, S.; Holz, B.; Fuchs, C.; Stolz, W.; Heimbrodt, W.

    2017-01-01

    (Ga,In)As/GaAs/Ga(As,Sb) multi-quantum well heterostructures have been investigated using continuous wave and time-resolved photoluminescence spectroscopy at various temperatures. A complex interplay was observed between the excitonic type-II transitions with electrons in the (Ga,In)As well and holes in the Ga(As,Sb) well and the type-I excitons in the (Ga,In)As and Ga(As,Sb) wells. The type-II luminescence exhibits a strongly non-exponential temporal behavior below a critical temperature of T c = 70 K. The transients were analyzed in the framework of a rate-equation model. It was found that the exciton relaxation and hopping in the localized states of the disordered ternary Ga(As,Sb) are the decisive processes to describe the dynamics of the type-II excitons correctly.

  2. Recombination dynamics of a localized exciton bound at basal stacking faults within the m-plane ZnO film

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S.; Liu, W.-R. [Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Hsu, H. C., E-mail: hsuhc@mail.ncku.edu.tw, E-mail: wfhsieh@mail.nctu.edu.tw [Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, 701 Tainan, Taiwan (China); Lin, B. H.; Hsu, C.-H. [Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Kuo, C. C.; Hsieh, W. F., E-mail: hsuhc@mail.ncku.edu.tw, E-mail: wfhsieh@mail.nctu.edu.tw [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Eriksson, M. O.; Holtz, P. O. [Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping (Sweden)

    2014-07-07

    We investigated the carrier dynamics near basal stacking faults (BSFs) in m-plane ZnO epitaxial film. The behaviors of the type-II quantum wells related to the BSFs are verified through time-resolved and time-integrated photoluminescence. The decay time of the emission of BSFs is observed to have a higher power law value and longer decay time than the emission of the donor-bound excitons. The spectral-dependent decay times reveal a phenomenon of carriers migrating among band tail states, which are related to the spatial distribution of the type-II quantum wells formed by the BSFs. A high density of excited carriers leads to a band bending effect, which in turn causes a blue-shift of the emission peak of BSFs with a broadened distribution of band tail states.

  3. Light-Cone Distribution Amplitudes for Heavy-Quark Hadrons

    CERN Document Server

    Bell, Guido; Wang, Yu-Ming; Yip, Matthew W Y

    2013-01-01

    We construct parametrizations of light-cone distribution amplitudes (LCDAs) for B-mesons and Lambda_b-baryons that obey various theoretical constraints, and which are simple to use in factorization theorems relevant for phenomenological applications in heavy-flavour physics. In particular, we find the eigenfunctions of the Lange-Neubert renormalization kernel, which allow for a systematic implementation of renormalization-group evolution effects for both B-meson and \\Lambda_b-baryon decays. We also present a new strategy to construct LCDA models from momentum-space projectors, which can be used to implement Wandzura-Wilczek--like relations, and which allow for a comparison with theoretical approaches that go beyond the collinear limit for the light-quark momenta in energetic heavy-hadron decays.

  4. Higgs-Boson Production in Association with Heavy Quarks

    OpenAIRE

    2006-01-01

    Associated production of a Higgs boson with a heavy, i.e. top or bottom, quark-anti-quark pair provide observation channels for Higgs bosons at the LHC which can be used to measure the respective Yukawa couplings. For the light supersymmetric Higgs boson we present SUSY-QCD corrections at the one-loop level, which constitute a significant contribution to the cross section.

  5. The B*Bpi coupling using relativistic heavy quarks

    CERN Document Server

    Flynn, J M; Kawanai, T; Lehner, C; Samways, B; Sachrajda, C T; Van de Water, R S; Witzel, O

    2015-01-01

    We report on a calculation of the B*Bpi coupling in lattice QCD. The strong matrix element for a B* to Bpi transition is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HMChPT) for B mesons. We carry out our calculation directly at the b-quark mass using a non-perturbatively tuned clover action that controls discretization effects of order pa and (ma)^n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of ainverse = 1.729(25) GeV, ainverse = 2.281(28) GeV, and unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HMChPT coupling g_b = 0.56(3)stat(7)sys in the continuum and at the physical light-quark masses. This is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between ...

  6. Prospects for collider searches for dark matter with heavy quarks

    Energy Technology Data Exchange (ETDEWEB)

    Artoni, Giacomo [Brandeis Univ., Waltham, MA (United States); Lin, Tongyan [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); Penning, Bjoern [Univ. of Chicago, IL (United States); Univ. of Chicago, IL (United States). Enrico Fermi Inst.; Sciolla, Gabriella [Brandeis Univ., Waltham, MA (United States); Venturini, Alessio [Brandeis Univ., Waltham, MA (United States)

    2013-08-05

    We present projections for future collider searches for dark matter produced in association with bottom or top quarks. Such production channels give rise to final states with missing transverse energy and one or more b-jets. Limits are given assuming an effective scalar operator coupling dark matter to quarks, where the dedicated analysis discussed here improves significantly over a generic monojet analysis. We give updated results for an anticipated high-luminosity LHC run at 14 TeV and for a 33 TeV hadron collider.

  7. Heavy quark potential from QCD-related effective coupling

    Science.gov (United States)

    Ayala, César; González, Pedro; Vento, Vicente

    2016-12-01

    We implement our past investigations of quark-antiquark interaction through a non-perturbative running coupling defined in terms of a gluon mass function, similar to that used in some Schwinger-Dyson approaches. This coupling leads to a quark-antiquark potential, which satisfies not only asymptotic freedom but also describes linear confinement correctly. From this potential, we calculate the bottomonium and charmonium spectra below the first open flavor meson-meson thresholds and show that for a small range of values of the free parameter determining the gluon mass function an excellent agreement with data is attained.

  8. Measurement of heavy-quark jet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-04-15

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb{sup -1}. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, p{sup jet}{sub T}, and pseudorapidity, {eta}{sup jet}, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  9. Measurement of heavy-quark jet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H.; Gueta, O.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A. [Tel Aviv University, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv (Israel); Abt, I.; Caldwell, A.; Reisert, B.; Schmidke, W.B. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L.; Bold, T.; Gach, G.; Grabowska-Bold, I.; Kisielewska, D.; Przybycien, M.; Suszycki, L. [AGH-University of Science and Technology, Faculty of Physics and Applied Computer Science, Cracow (Poland); Adamus, M.; Plucinski, P.; Tymieniecka, T. [Institute for Nuclear Studies, Warsaw (Poland); Aggarwal, R.; Kaur, M.; Kaur, P.; Singh, I. [Panjab University, Department of Physics, Chandigarh (India); Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A. [University Bologna (Italy); INFN Bologna, Bologna (Italy); Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Margotti, A.; Nania, R.; Polini, A. [INFN Bologna, Bologna (Italy); Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S. [Moscow Engineering Physics Institute, Moscow (Russian Federation); Arneodo, M.; Ruspa, M. [Universita del Piemonte Orientale, Novara (Italy); INFN, Torino (Italy); Aushev, V.; Dolinska, G.; Gogota, O.; Korol, I. [National Academy of Sciences, Institute for Nuclear Research, Kyiv (Ukraine); National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Aushev, Y.; Bartosik, N.; Bolilyi, O.; Bondarenko, K.; Kadenko, I.; Kuprash, O.; Lontkovskyi, D.; Makarenko, I.; Onishchuk, Yu.; Salii, A.; Tomalak, O.; Volynets, O.; Zenaiev, O.; Zolko, M. [National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Bachynska, O.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Bot, D.; Ciesielski, R.; Coppola, N.; Fang, S.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T. [and others

    2011-05-15

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb{sup -1}. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, p{sub T}{sup jet}, and pseudorapidity, {eta}{sup jet}, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  10. Searches for baryons with multiple heavy quarks at LHCb

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Hadrons are systems bound by the strong interaction, which is described at the fundamental level by quantum chromodynamics (QCD). While QCD is well understood at high energy in the perturbative regime, low-energy phenomena, such as the binding of quarks and gluons within hadrons, are more difficult to predict. High precision measurements are then of paramount importance to test the reliability of several models and computational techniques, such as constituent-quark models or lattice-QCD calculations, in predicting the mass spectrum and the properties of hadrons. Owing to its excellent capabilities with particle identification, tracking and vertex reconstruction, LHCb is in a unique position to make significant contributions to the sector of particle spectroscopy. For example, five narrow structures have been recently observed in the $\\Xi_c^+K^-$ mass spectrum, consistent with excited $\\Omega_c^{0}$ states, composed of a charm quark and two strange quarks. Despite the fact that the quark model predicts the ex...

  11. B-decays in the heavy-quark expansion

    Energy Technology Data Exchange (ETDEWEB)

    Becher, Thomas; /Fermilab

    2004-11-01

    Progress in the theoretical description of B-meson decays, in particular decays to light hadrons, is reviewed. The factorization properties of such decays can be analyzed using the soft-collinear effective theory. Applications of the effective theory to both inclusive and exclusive decays are discussed.

  12. Heavy quark analogues of the {theta} and their excitations

    Energy Technology Data Exchange (ETDEWEB)

    Maltman, Kim [Department of Mathematics and Statistics, York University, 4700 Keele St., Toronto, ON, M3J 1P3 (Canada) and CSSM, University of Adelaide, Adelaide, SA 5005 (Australia)]. E-mail: kmaltman@yorku.ca

    2004-12-23

    Predictions for the low-lying excitation spectrum of positive parity pentaquark systems containing one c-bar or b-bar antiquark and four light u, d quarks are obtained in the quark model picture for models with spin-dependent interactions given either by effective color-magnetic (CM) exchange or effective Goldstone boson (GB) exchange. For the GB model, 4 excited states are predicted to lie within approx. = m{sub {delta}}-m{sub N} of the J{sup P}=1/2{sup +} ground state while, for the CM model, 10 states are expected in the same range. Both the lowest excitation energy and the relative splittings are much smaller in the CM case. These predictions are on the same footing as those for the analogous splittings in the non-exotic baryon sector and, as such, provide a means of not only testing the models, but potentially ruling out either one, or both.

  13. Soft Gluon Radiation off Heavy Quarks beyond Eikonal Approximation

    CERN Document Server

    Bhattacharyya, Trambak; Abir, Raktim

    2016-01-01

    It is known that gluon bremsstrahlung emission off heavy flavor jet is suppressed in the forward direction compared to that of light quark due to the mass effect ($`$dead cone effect'). Most of the models that address jet quenching generally assume that a jet always travels in straight eikonal path. However, once the eikonal approximation of propagation is called off and jet is allowed to bend, additional gluons pop-up within the so called `depopulated' region deluging the dead cone. This color synchrotron by color charge, once wound in an ambiance of color field, seems to be very apt for better understanding of jet quenching in hot and dense deconfined quark-gluon medium.

  14. Heavy quark production in neutrino deep-inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.A.; Vakili, M.; Wu, V. [University of Cincinnati, Cincinnati, Ohio 45221 (United States); Bazarko, A.O.; Conrad, J.M.; Formaggio, J.A.; Kim, J.H.; King, B.J.; Koutsoliotas, S.; McNulty, C.; Mishra, S.R.; Romosan, A.; Sculli, F.J.; Seligman, W.G.; Shaevitz, M.H.; Spentzouris, P.; Stern, E.G.; Tamminga, B.M.; Vaitaitis, A. [Columbia University, New York, New York 10027 (United States); Bugel, L.; Lamm, M.J.; Marsh, M.; Nienaber, P.; Yu, J. [Fermilab, Batavia, Illinois 60510 (United States); Alton, A.; Bolton, T.; Goldman, J.; Goncharov, M.; Naples, D. [Kansas State University, Manhattan, Kansas 66506 (United States); Buchholz, D.; Harris, D.A.; Schellman, H.M.; Zeller, G.P. [Northwestern University, Evanston, Illinois 97403 (United States); Drucker, R.B.; Frey, R.; Mason, D. [University of Oregon, Eugene, Oregon 97403 (United States); de Barbaro, P.; Bodek, A.; Budd, H.; McFarland, K.S.; Sakumoto, W.K.; Yang, U.K. [University of Rochester, Rochester, New York 14627 (United States); Smith, W.H. [University of Wisconsin, Madison, Wisconsin 45207 (United States)

    1999-02-01

    Charm production by neutrino charged-current interactions produces two muon (dimuon) events which are easily identified. This signal provides an important method to measure the strange sea and the mass of the charm quark. Several experiments, including CCFR, CDHS and CHARM II, have performed analyses of such events. The results of these analyses are summarized with emphasis on CCFR and improvements made by NuTeV. {copyright} {ital 1999 American Institute of Physics.}

  15. Hadronic weak decays in the heavy quark limit

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Matthaeus

    2011-12-20

    We mainly investigate the parameters vertical stroke V{sub ub} vertical stroke and {gamma} of the CKM matrix that are associated with b {yields} u transitions in electroweak theory. These investigations are motivated by the search for New Physics, which is expected to have an influence on CP-violation. There is a wealth of experimental data available from an active experimental community, which provides a broad foundation to determine and control parameters of the theory. In order to make use of a large amount of data we discuss exclusive charmless decays of B{sub d} and B{sub s} mesons to light hadrons. We apply an expansion in {lambda}{sub QCD}/m{sub b} and express nonperturbative QCD by light cone distribution amplitudes and form factors. This procedure is known as QCD factorization. We discuss two separate classes of B-decays. In the first part of this thesis we perform a phenomenological analysis of B-decays to longitudinal vector mesons, B {yields} V{sub L}V{sub L}. We exploit the smallness of 2 parameters in the decay B{sub d} {yields} {rho}{sup +}{sub L}{rho}{sup -}{sub L} and express CKM parameters in an expansion. We observe that for vertical stroke V{sub ub} vertical stroke such an expansion starts at second order and use this fact to provide a precise value assuming the standard model. This method also serves to constrain possible New Physics phases in the mixing of B{sub d} mesons. A major troubling aspect of hadronic decays are the general power corrections of order 10%. Therefore we develop a strategy to constrain the power corrections with the help of an additional measurement of a branching fraction. Apart from CKM parameters, we also extract the hadronic parameter in order to check the leading power prediction. On the experimental side particularly the sector of B{sub s} decays will be developed in the future. Among the decays into hadrons that are suitable for probes of New Physics is B{sub s} {yields} {phi}{phi}. We provide an upper bound for the CP violation, based on experimental determinations of hadronic parameters that have corrections of unknown size. The second part is devoted to the development of necessary ingredients and tools to compute decays that involve baryons. Specifically we regard the decay B{sub s} {yields}pp and discuss the leading contributions. This decay is helicity suppressed, which makes it necessary to calculate up to the first power in {lambda}{sub QCD}/m{sub b}. Computations at first power in baryonic systems require the input of next-to-leading soft and hard quantities. We determine the necessary power suppressed terms on the soft and the hard side and give explicit formulas for the decay amplitude. The result may be presented as an integration over 4 parameters with parameter dependent integration boundaries. We describe a systematic method to regulate these integrals. The result of the regulation is given for proton form factors. In order to systematically disentangle divergent parts for more complex integrals we develop a method for cut-off-regulated integrals.

  16. FONLL calculations for heavy quark production in nuclear collisions

    CERN Document Server

    Niel, Elisabeth Maria

    2017-01-01

    The ALICE detector at the LHC has been designed to study the collisions of heavy nuclei at energies much higher then the previous dedicated experiments at the Relativistic Heavy-Ion Collider (RHIC) of the Brookhaven National Laboratory. Colliding heavy nuclei allows to reproduce the hot and dense plasma of quarks and gluons (QGP) existing right after the Big Bang and hence study the very first instants of universe’s existence. In heavy ions collisions, heavy flavours, such as beauty and charm quark, are fundamental probes for the quark gluon plasma properties. That is because they experience the entire evolution of the system since they are produced at the very beginning. They are indeed a very powerful tool to test field theories such as Quantum Chromodynamics (QCD). Theoretical models predict that a fast parton(quark or gluon) looses energy while traversing a medium composed of colour charges. This phenomenon is called "jet quenching", it can be used to describe the QGP. It was first observed at RHIC by m...

  17. Final Results on Heavy Quarks at LEP and SLD

    CERN Document Server

    Stocchi, A

    2002-01-01

    In the last decade, the LEP and SLD experiments played a central role in the study of B hadrons (hadrons containing a b quark). New B hadrons have been observed ($B^0_s$, \\Lambda_b$, $\\Xi_b$ and $B^{**}$) and their production and decay properties have been measured. In this paper we will focus on measurements of the CKM matrix elements: $|V_{cb}|$, $|V_{ub}|$, $|V_{td}|$ and $|V_{ts}|$. We will show how all these measurements, together with theoretical developments, have significantly improved our knowledge on the flavour sector of the Standard Model.

  18. Measurement of heavy-quark jet photoproduction at HERA

    CERN Document Server

    Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Aushev, V; Aushev, Y; Bachynska, O; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartosik, N; Bartsch, D; Basile, M; Behnke, O; Behr, J; Behrens, U; Bellagamba, L; Bertolin, A; Bhadra, S; Bindi, M; Blohm, C; Bokhonov, V; Bołd, T; Bolilyi, O; Bondarenko, K; Boos, E G; Borras, K; Boscherini, D; Bot, D; Brock, I; Brownson, E; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Brzozowska, B; Bussey, P J; Bylsma, B; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; D'Agostini, G; Corso, F Dal; del Peso, J; Dementiev, R K; De Pasquale, S; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dolinska, G; Doyle, A T; Drugakov, V; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Fang, S; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Forrest, M; Foster, B; Fourletov, S; Gach, G; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gladilin, L K; Gladkov, D; Glasman, C; Gogota, O; Golubkov, Yu A; Göttlicher, P; Grabowska-Bołd, I; Grebenyuk, J; Gregor, I; Grigorescu, G; Grzelak, G; Gueta, O; Gwenlan, C; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Hilger, E; Hochman, D; Hori, R; Horton, K; Hüttmann, A; Ibrahim, Z A; Iga, Y; Ingbir, R; Ishitsuka, M; Jakob, H -P; Januschek, F; Jimenez, M; Jones, T W; Jüngst, M; Kadenko, I; Kahle, B; Kamaluddin, B; Kananov, S; Kanno, T; Karshon, U; Karstens, F; Katkov, I I; Kaur, M; Kaur, P; Keramidas, A; Khein, L A; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kooijman, P; Korol, Ie; Korzhavina, I A; Kotański, A; Kötz, U; Kowalski, H; Kulinski, P; Kuprash, O; Kuze, M; Lee, A; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Ling, T Y; Lisovyi, M; Lobodzinska, E; Lohmann, W; Löhr, B; Lohrmann, E; Long, K R; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Łużniak, P; Maeda, J; Magill, S; Makarenko, I; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Mattingly, M C K; Melzer-Pellmann, I -A; Mergelmeyer, S; Miglioranzi, S; Idris, F Mohamad; Monaco, V; Montanari, A; Morris, J D; Mujkic, K; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Nobe, T; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Oliver, K; Olkiewicz, K; Onishchuk, Yu; Papageorgiu, K; Parenti, A; Paul, E; Pawlak, J M; Pawlik, B; Pelfer, P G; Pellegrino, A; Perlanski, W; Perrey, H; Piotrzkowski, K; Plucinski, P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycień, M; Raval, A; Reeder, D D; Reisert, B; Ren, Z; Repond, J; Ri, Y D; Robertson, A; Roloff, P; Ron, E; Rubinsky, I; Ruspa, M; Sacchi, R; Salii, A; Samson, U; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schönberg, V; Schörner-Sadenius, T; Schwartz, J; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Singh, I; Skillicorn, I O; Słomiński, W; Smith, W H; Sola, V; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Stern, A; Stewart, T P; Stifutkin, A; Stopa, P; Suchkov, S; Susinno, G; Suszycki, L; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tapper, A D; Tassi, E; Terrón, J; Theedt, T; Tiecke, H; Tokushuku, K; Tomalak, O; Tomaszewska, J; Tsurugai, T; Turcato, M; Tymieniecka, T; Uribe-Estrada, C; Vázquez, M; Verbytskyi, A; Viazlo, O; Vlasov, N N; Volynets, O; Walczak, R; Abdullah, W A T Wan; Whitmore, J J; Whyte, J; Wiggers, L; Wing, M; Wlasenko, M; Wolf, G; Wolfe, H; Wrona, K; Yagües-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Żarnecki, A F; Zawiejski, L; Zenaiev, O; Zeuner, W; Zhautykov, B O; Zhmak, N; Zhou, C; Zichichi, A; Zolko, M; Zotkin, D S; Zulkapli, Z

    2011-01-01

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 $pb^{-1}$. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, $p_{T}^{\\text{jet}}$, and pseudorapidity, $\\eta^{\\text{jet}}$, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions.

  19. Uncovering the microscopic mechanism of strand exchange during RecA mediated homologous recombination using all-atom molecular dynamics simulations

    Science.gov (United States)

    Shankla, Manish; Yoo, Jejoong; Aksimentiev, Aleksei

    2012-02-01

    Homologous recombination (HR) is a key step during the repair process of double-stranded DNA (dsDNA) breakage. RecA is a protein that mediates HR in bacteria. RecA monomers polymerize on a single-stranded DNA (ssDNA) separated from the broken dsDNA to form a helical filament, thus allowing strand exchange to occur. Recent crystal structures depict each RecA monomer in contact with three contiguous nucleotides called DNA triplets. Surprisingly, the conformation of each triplet is similar to that of a triplet in B-form DNA. However, in the filament the neighboring triplets are separated by loops of the RecA proteins. Single molecule experiments demonstrated that strand exchange propagation occurs in 3 base-pair increments. However, the temporal resolution of the experiments was insufficient to determine the exact molecular mechanism of the triplet propagation. Using all-atom molecular dynamics simulations, we investigated the effect of both the RecA protein and the conformation of the bound ssDNA fragment on the stability of the duplex DNA intermediate formed during the strand-exchange process. Specifically, we report simulations of force-induced unzipping of duplex DNA in the presence and absence of the RecA filament that explored the effect of the triplet ladder conformation.

  20. 自旋极化度对GaAs量子阱中吸收饱和效应与载流子复合动力学的影响研究%Effects of spin p olarization on absorption saturation and recombination dynamics of carriers in (001) GaAs quantum wells

    Institute of Scientific and Technical Information of China (English)

    方少寅; 陆海铭; 赖天树

    2015-01-01

    In this paper, the ultrafast dynamics of spin relaxation and recombination of photoexcited carriers has been studied in (001) GaAs quantum wells using a time-resolved pump-probe absorption spectroscopy under a nearly resonant excitation of heavy-hole excitons. It is found that the spin polarization of carriers influences both absorption saturation of linear polarized light and recombination dynamics of carriers. Pump fluence dependence of the ultrafast dynamics of spin relaxation and recombination of carriers is further studied, which shows that the effect of spin polarization on linearly polarized absorption saturation is reduced with lowering pump fluence. Spin-polarization-dependent absorption saturation effect can be ignored only as the pump fluence is weak. However, spin-polarization dependence of recombination dynamics is presented in turn at low pump fluence. Our analysis shows that such dependence originates from the spinpolarization dependence of the density of excitons formed in the excited carriers because recombination time constants of excitons and free carriers are very different so that the ratio of exciton density to free carrier density can influence the recombination dynamics. The spin-polarization dependence of ultrafast recombination dynamics of photoexcited carriers implies that the recombination time constant in the calculation of spin relaxation time from spin relaxation dynamics should be the recombination time of spin-polarized carriers, rather than the recombination lifetime of non-spin-polarized carriers as done currently. Exciton density is estimated based on 2D mass action law, which agrees very well with our experimental results. The good agreement between theoretical calculation and experimental results reveals that the effect of Coulomb screening on the formation of excitons may be ignored for a lower excited carrier density.

  1. Electron beam induced and microemulsion templated synthesis of CdSe quantum dots: tunable broadband emission and charge carrier recombination dynamics

    Science.gov (United States)

    Guleria, Apurav; Singh, Ajay K.; Rath, Madhab C.; Adhikari, Soumyakanti

    2015-04-01

    CdSe quantum dots (QDs) were synthesized by a rapid and one step templated approach inside the water pool of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) based water-in-oil microemulsions (MEs) via electron beam (EB) irradiation technique with high dose rate, which favours high nucleation rate. The interplay of different experimental parameters such as precursor concentration, absorbed dose and {{W}0} values (aqueous phase to surfactant molar ratio) of MEs were found to have interesting consequences on the morphology, photoluminescence (PL), surface composition and carrier recombination dynamics of as-grown QDs. For instance, highly stable ultrasmall (∼1.7 nm) bluish-white light emitting QDs were obtained with quantum efficiency (η) of ∼9%. Furthermore, QDs were found to exhibit tunable broadband light emission extending from 450 to 750 nm (maximum FWHM ∼180 nm). This could be realized from the CIE (Commission Internationale d’Eclairage) chromaticity co-ordinates, which varied across the blue region to the orange region thereby, conferring their potential application in white light emitting diodes. Additionally, the average PL lifetime ≤ft( ≤ft \\right) values could be varied from 18 ns to as high as 74 ns, which reflect the role of surface states in terms of their density and distribution. Another interesting revelation was the self-assembling of the initially formed QDs into nanorods with high aspect ratios ranging from 7 to 20, in correspondence with the {{W}0} values. Besides, the fundamental roles of the chemical nature of water pool and the interfacial fluidity of AOT MEs in influencing the photophysical properties of QDs were investigated by carrying out a similar study in CTAB (cetyltrimethylammonium bromide; cationic surfactant) based MEs. Surprisingly, very profound and contrasting results were observed wherein ≤ft and η of the QDs in case of CTAB MEs were found to be at least three times lower as compared to that in AOT MEs.

  2. Recombination dynamics of a human Y-chromosomal palindrome: rapid GC-biased gene conversion, multi-kilobase conversion tracts, and rare inversions.

    Directory of Open Access Journals (Sweden)

    Pille Hallast

    Full Text Available The male-specific region of the human Y chromosome (MSY includes eight large inverted repeats (palindromes in which arm-to-arm similarity exceeds 99.9%, due to gene conversion activity. Here, we studied one of these palindromes, P6, in order to illuminate the dynamics of the gene conversion process. We genotyped ten paralogous sequence variants (PSVs within the arms of P6 in 378 Y chromosomes whose evolutionary relationships within the SNP-defined Y phylogeny are known. This allowed the identification of 146 historical gene conversion events involving individual PSVs, occurring at a rate of 2.9-8.4×10(-4 events per generation. A consideration of the nature of nucleotide change and the ancestral state of each PSV showed that the conversion process was significantly biased towards the fixation of G or C nucleotides (GC-biased, and also towards the ancestral state. Determination of haplotypes by long-PCR allowed likely co-conversion of PSVs to be identified, and suggested that conversion tract lengths are large, with a mean of 2068 bp, and a maximum in excess of 9 kb. Despite the frequent formation of recombination intermediates implied by the rapid observed gene conversion activity, resolution via crossover is rare: only three inversions within P6 were detected in the sample. An analysis of chimpanzee and gorilla P6 orthologs showed that the ancestral state bias has existed in all three species, and comparison of human and chimpanzee sequences with the gorilla outgroup confirmed that GC bias of the conversion process has apparently been active in both the human and chimpanzee lineages.

  3. Recombinant Technology and Probiotics

    Directory of Open Access Journals (Sweden)

    Icy D’Silva

    2011-09-01

    Full Text Available Recombinant technology has led the way to monumental advances in the development of useful molecules, including the development of safe probiotics. The development of novel approaches using recombinant technology and probiotics that allow accurate targeting of therapeutics to the mucosa is an interesting area of research. The creation and use of recombinant probiotics expressing recombinantovalbumin, recombinant ovalbumin mutants and yet-to-be-designed recombinant hypo/non-allergenic molecules offer the opportunity to further investigate their effects for food, nutrition, environment andhealth. This review highlights advances in native probiotics and recombinant probiotics expressing native and recombinant molecules for food, nutrition, environment and health.

  4. Recombinant Technology and Probiotics

    OpenAIRE

    Icy D’Silva

    2011-01-01

    Recombinant technology has led the way to monumental advances in the development of useful molecules, including the development of safe probiotics. The development of novel approaches using recombinant technology and probiotics that allow accurate targeting of therapeutics to the mucosa is an interesting area of research. The creation and use of recombinant probiotics expressing recombinantovalbumin, recombinant ovalbumin mutants and yet-to-be-designed recombinant hypo/non-allergenic molecule...

  5. Dynamic observation of splenocyte apoptosis in mice immunized with recombinant vaccine Bifidobacterium bifidum pGEX-Sj14-3-3 of Schistosoma japonicum

    Institute of Scientific and Technical Information of China (English)

    张宁

    2013-01-01

    Objective To investigate the effects of recombinant vaccine Bifidobacterium bifidum(Bb) pGEX-Sj14-3-3 on splenocyte apoptosis in BALB/c mice. Methods Ninety-six BALB/c mice were randomly divided into two groups according to their body mass: per os group(PO) and

  6. Heavy quark resonances as a probe of quark-gluon plasma: optimization of the muon spectrometer of ALICE experiment and study of the J/{psi} production in the NA60 experiment; Les resonances de quarks lourds comme sonde du plasma de quarks et de gluons: optimisation du spectrometre a muons de l'experience ALICE et etude de la production du J/{psi} dans l'experience NA60

    Energy Technology Data Exchange (ETDEWEB)

    Pillot, Ph

    2005-05-15

    The study of heavy quark production such as J/{psi} (cc-bar resonance) and {upsilon} (bb-bar resonance) in heavy ion collisions at high incident energies has been proposed as a tool to investigate the formation of a Quark Gluon Plasma. Experimentally, these resonances can be detected through their decay channel into a muon pair, using a muon spectrometer. The optimal resolution of a muon spectrometer cannot be reached unless the position of the different tracking detectors are accurately known. In the first part of the work reported in this thesis are presented the design and performances of the Geometry Monitoring System of the ALICE experiment's muon spectrometer at LHC. This system, which is composed of several hundreds of RASNIK derived optical devices, allows to measure displacements and deformations of the chambers with a precision better than a hundred of microns. Thanks to its muon spectrometer associated with a vertex telescope, the NA60 experiment studies the dimuon production in nucleus-nucleus collisions at CERN SPS. The second part of the work reported in this thesis is related to the analysis of the data collected in indium-indium collisions at 158 GeV/c/nucleon. More specifically, the J/{psi} production together with its transverse momentum and transverse mass distributions are studied as a function of the centrality of the collision. The different results arising from our analysis are then compared to those obtained previously by NA38 and NA50, allowing a better understanding of the ultrarelativistic heavy ion collisions. (author)

  7. Investigating correlated few-electron dynamics and QED contributions by means of dielectronic recombination into highly-charged Fe, Kr, Xe, Ba, W, and Hg ions

    Energy Technology Data Exchange (ETDEWEB)

    Harman, Z.; Maeckel, V.; Martinez Gonzalez, A.J.; Crespo Lopez-Urrutia, J.R.; Jentschura, U.D.; Keitel, C.H.; Postavaru, O.; Tawara, H.; Ullrich, J. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Artemyev, A.N.; Tupitsyn, I.I. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); St. Petersburg State University, Oulianovskaya 1, 198504 St. Petersburg (Russian Federation)

    2007-07-01

    The photorecombination of highly charged He- to B-like ions has been explored in the atomic number range Z=26 to 80 with the Heidelberg electron beam ion trap. The energies of state-selected dielectronic recombination (DR) resonances were determined over the KLL region. At the present level of experimental accuracy, it becomes possible to make a detailed comparison to vario us theoretical approaches and methods, all of which include relativistic and quantum electrodynamic (QED) effects. Theoretical resonance energies for KLL DR are calculated by various means. The comparison of theoretical values with the experimental energies shows a good overall agreement. Few discrepancies are found in specific recombination resonances for initially Li- and Be-like heavy ions.

  8. Fusion: a tale of recombination in an asexual fungus: The role of nuclear dynamics and hyphal fusion in horizontal chromosome transfer in Fusarium oxysporum

    OpenAIRE

    Shahi, S.

    2016-01-01

    Recent studies have shown that not only meiotic recombination is responsible for the fast evolution of fungal pathogens. In the asexual fungus F. oxysporum (Fo) the "fast" evolving part of the genome is organized into small chromosomes and one such chromosome houses all effector genes and is referred to as the "pathogenicity" chromosome. This pathogenicity chromosome can be horizontally transferred to a non-pathogenic strain, conferring pathogenicity. Here we use Fo as a model organism to add...

  9. Research on the Dynamic Recombining Algorithm About the Multiple Missiles Cooperative Attacking Net Combat System%多弹协同攻击网络化作战系统动态重组算法研究

    Institute of Scientific and Technical Information of China (English)

    王君; 朱永文; 崔颢; 梁文波

    2011-01-01

    The combat thinking is put forward,which is to set up multiple missiles cooperative attacking net combat system based on the dynamic founded net with many remote range air-to-air missiles.And the dynamic founding net system's topology relation finding algorithm is realized by using the searching method in chart theory and defining the application layer data message,which is also used to study the dynamic founding net system's recombining algorithm and to convert the topology relation to the nothing orientation chart Abstractively.By research on dynamic recombining problem with chart theory tools,some reference is provided for new type of air-to-air missiles' cooperative attacking net combat system when the system member node is destroyed in battle field or something wrong is with the communication system.%提出了利用多枚远程空空导弹在空中动态组网,构建多弹协同攻击的网络化作战系统的作战思想.利用图论中的搜索方法、定义应用层数据报文实现动态组网系统的拓扑关系发现算法,并利用拓扑关系发现算法研究了动态组网系统的动态重组算法,将动态组网系统拓扑关系抽象成图论中的无向图,利用图论工具来研究系统成员节点战损与通信故障情况下动态重组问题,为新一代空空导弹协同攻击网络化作战系统的研究提供一定的参考.

  10. Cascading electron and hole transfer dynamics in a CdS/CdTe core-shell sensitized with bromo-pyrogallol red (Br-PGR): slow charge recombination in type II regime.

    Science.gov (United States)

    Maity, Partha; Debnath, Tushar; Chopra, Uday; Ghosh, Hirendra Nath

    2015-02-14

    Ultrafast cascading hole and electron transfer dynamics have been demonstrated in a CdS/CdTe type II core-shell sensitized with Br-PGR using transient absorption spectroscopy and the charge recombination dynamics have been compared with those of CdS/Br-PGR composite materials. Steady state optical absorption studies suggest that Br-PGR forms strong charge transfer (CT) complexes with both the CdS QD and CdS/CdTe core-shell. Hole transfer from the photo-excited QD and QD core-shell to Br-PGR was confirmed by both steady state and time-resolved emission spectroscopy. Charge separation was also confirmed by detecting electrons in the conduction band of the QD and the cation radical of Br-PGR as measured from femtosecond transient absorption spectroscopy. Charge separation in the CdS/Br-PGR composite materials was found to take place in three different pathways, by transferring the photo-excited hole of CdS to Br-PGR, electron injection from the photo-excited Br-PGR to the CdS QD, and direct electron transfer from the HOMO of Br-PGR to the conduction band of the CdS QD. However, in the CdS/CdTe/Br-PGR system hole transfer from the photo-excited CdS to Br-PGR and electron injection from the photo-excited Br-PGR to CdS take place after cascading through the CdTe shell QD. Charge separation also takes place via direct electron transfer from the Br-PGR HOMO to the conduction band of CdS/CdTe. Charge recombination (CR) dynamics between the electron in the conduction band of the CdS QD and the Br-PGR cation radical were determined by monitoring the bleach recovery kinetics. The CR dynamics were found to be much slower in the CdS/CdTe/Br-PGR system than in the CdS/Br-PGR system. The formation of the strong CT complex and the separation of charges cascading through the CdTe shell help to slow down charge recombination in the type II regime.

  11. Therapeutic Recombinant Monoclonal Antibodies

    Science.gov (United States)

    Bakhtiar, Ray

    2012-01-01

    During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

  12. Therapeutic Recombinant Monoclonal Antibodies

    Science.gov (United States)

    Bakhtiar, Ray

    2012-01-01

    During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

  13. Single-crossover recombination and ancestral recombination trees.

    Science.gov (United States)

    Baake, Ellen; von Wangenheim, Ute

    2014-05-01

    We consider the Wright-Fisher model for a population of [Formula: see text] individuals, each identified with a sequence of a finite number of sites, and single-crossover recombination between them. We trace back the ancestry of single individuals from the present population. In the [Formula: see text] limit without rescaling of parameters or time, this ancestral process is described by a random tree, whose branching events correspond to the splitting of the sequence due to recombination. With the help of a decomposition of the trees into subtrees, we calculate the probabilities of the topologies of the ancestral trees. At the same time, these probabilities lead to a semi-explicit solution of the deterministic single-crossover equation. The latter is a discrete-time dynamical system that emerges from the Wright-Fisher model via a law of large numbers and has been waiting for a solution for many decades.

  14. Antagonistic experimental coevolution with a parasite increases host recombination frequency

    Directory of Open Access Journals (Sweden)

    Kerstes Niels AG

    2012-02-01

    Full Text Available Abstract Background One of the big remaining challenges in evolutionary biology is to understand the evolution and maintenance of meiotic recombination. As recombination breaks down successful genotypes, it should be selected for only under very limited conditions. Yet, recombination is very common and phylogenetically widespread. The Red Queen Hypothesis is one of the most prominent hypotheses for the adaptive value of recombination and sexual reproduction. The Red Queen Hypothesis predicts an advantage of recombination for hosts that are coevolving with their parasites. We tested predictions of the hypothesis with experimental coevolution using the red flour beetle, Tribolium castaneum, and its microsporidian parasite, Nosema whitei. Results By measuring recombination directly in the individuals under selection, we found that recombination in the host population was increased after 11 generations of coevolution. Detailed insights into genotypic and phenotypic changes occurring during the coevolution experiment furthermore helped us to reconstruct the coevolutionary dynamics that were associated with this increase in recombination frequency. As coevolved lines maintained higher genetic diversity than control lines, and because there was no evidence for heterozygote advantage or for a plastic response of recombination to infection, the observed increase in recombination most likely represented an adaptive host response under Red Queen dynamics. Conclusions This study provides direct, experimental evidence for an increase in recombination frequency under host-parasite coevolution in an obligatory outcrossing species. Combined with earlier results, the Red Queen process is the most likely explanation for this observation.

  15. The recombinational anatomy of a mouse chromosome.

    Directory of Open Access Journals (Sweden)

    Kenneth Paigen

    2008-07-01

    Full Text Available Among mammals, genetic recombination occurs at highly delimited sites known as recombination hotspots. They are typically 1-2 kb long and vary as much as a 1,000-fold or more in recombination activity. Although much is known about the molecular details of the recombination process itself, the factors determining the location and relative activity of hotspots are poorly understood. To further our understanding, we have collected and mapped the locations of 5,472 crossover events along mouse Chromosome 1 arising in 6,028 meioses of male and female reciprocal F1 hybrids of C57BL/6J and CAST/EiJ mice. Crossovers were mapped to a minimum resolution of 225 kb, and those in the telomere-proximal 24.7 Mb were further mapped to resolve individual hotspots. Recombination rates were evolutionarily conserved on a regional scale, but not at the local level. There was a clear negative-exponential relationship between the relative activity and abundance of hotspot activity classes, such that a small number of the most active hotspots account for the majority of recombination. Females had 1.2x higher overall recombination than males did, although the sex ratio showed considerable regional variation. Locally, entirely sex-specific hotspots were rare. The initiation of recombination at the most active hotspot was regulated independently on the two parental chromatids, and analysis of reciprocal crosses indicated that parental imprinting has subtle effects on recombination rates. It appears that the regulation of mammalian recombination is a complex, dynamic process involving multiple factors reflecting species, sex, individual variation within species, and the properties of individual hotspots.

  16. Local carrier recombination and associated dynamics in m-plane InGaN/GaN quantum wells probed by picosecond cathodoluminescence

    Science.gov (United States)

    Zhu, Tongtong; Gachet, David; Tang, Fengzai; Fu, Wai Yuen; Oehler, Fabrice; Kappers, Menno J.; Dawson, Phil; Humphreys, Colin J.; Oliver, Rachel A.

    2016-12-01

    We report on spatially resolved and time-resolved cathodoluminescence (CL) studies of the recombination mechanisms of InGaN/GaN quantum wells (QWs) grown by metal-organic vapour phase epitaxy on bulk m-plane Ammono GaN substrates. As a result of the 2° miscut of the GaN substrate, the sample surface exhibits step bunches, where semi-polar QWs with a higher indium concentration than the planar m-plane QWs form during the QW growth. Spatially resolved time-integrated CL maps under both continuous and pulsed excitation show a broad emission band originating from the m-plane QWs and a distinct low energy emission originating from the semi-polar QWs at the step bunches. High resolution time-resolved CL maps reveal that when the m-QWs are excited well away from the step bunches the emission from the m-plane QWs decays with a time constant of 350 ps, whereas the emission originating semi-polar QWs decays with a longer time constant of 489 ps. The time constant of the decay from the semi-polar QWs is longer due to the separation of the carrier wavefunctions caused by the electric field across the semi-polar QWs.

  17. Novel Recombinant Sapovirus

    Science.gov (United States)

    Katayama, Kazuhiko; Miyoshi, Tatsuya; Uchino, Kiyoko; Oka, Tomoichiro; Tanaka, Tomoyuki; Takeda, Naokazu

    2004-01-01

    We determined the complete genome sequences of two sapovirus strains isolated in Thailand and Japan. One of these strains represented a novel, naturally occurring recombinant sapovirus. Evidence suggested the recombination site was at the polymerase-capsid junction within open reading frame one. PMID:15504283

  18. From Recombination Dynamics to Device Performance: Quantifying the Efficiency of Exciton Dissociation, Charge Separation, and Extraction in Bulk Heterojunction Solar Cells with Fluorine-Substituted Polymer Donors

    KAUST Repository

    Gorenflot, Julien

    2017-09-28

    An original set of experimental and modeling tools is used to quantify the yield of each of the physical processes leading to photocurrent generation in organic bulk heterojunction solar cells, enabling evaluation of materials and processing condition beyond the trivial comparison of device performances. Transient absorption spectroscopy, “the” technique to monitor all intermediate states over the entire relevant timescale, is combined with time-delayed collection field experiments, transfer matrix simulations, spectral deconvolution, and parametrization of the charge carrier recombination by a two-pool model, allowing quantification of densities of excitons and charges and extrapolation of their kinetics to device-relevant conditions. Photon absorption, charge transfer, charge separation, and charge extraction are all quantified for two recently developed wide-bandgap donor polymers: poly(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-difluorothiophene) (PBDT[2F]T) and its nonfluorinated counterpart poly(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-thiophene) (PBDT[2H]T) combined with PC71BM in bulk heterojunctions. The product of these yields is shown to agree well with the devices\\' external quantum efficiency. This methodology elucidates in the specific case studied here the origin of improved photocurrents obtained when using PBDT[2F]T instead of PBDT[2H]T as well as upon using solvent additives. Furthermore, a higher charge transfer (CT)-state energy is shown to lead to significantly lower energy losses (resulting in higher VOC) during charge generation compared to P3HT:PCBM.

  19. Dynamics of cervical langerhans cell counts in the course of HPV-positive CIN treatment with the use of human recombinant interferon gamma.

    Science.gov (United States)

    Sikorski, M; Bieda, T; Bobek, M; Zrubek, H

    2005-01-01

    Langerhans cells play a pivotal role as professional antigens presenting cells in cervical epithelium, thus changes in their density or/and function may profoundly influence the proper activation of the afferent arm of immune response in cases of HPV-related intraepithelial lesions. Assessment of intraepithelial Langerhans cell count changes in CIN I/CIN II after human recombinant interferon gamma (IFNgamma) application and correlation with clinical outcome. The present study is a part of prospective trial on IFNgamma application in the treatment of CIN I/CINII associated with high-risk HPV infection. Seventeen subjects underwent uniform IFNgamma treatment (four intracervical injections in a two-day interval for a total dose of 6,000,000 IU). Langerhans cells were stained within cervical punch biopsy specimens with the use of polyclonal anti-S-100 antibody according to the three-step indirect peroxidase protocol, and their mean count calculated for the following groups: before IFNgamma treatment launching, immediately after completion of the treatment, and after two months of follow-up. The analysis revealed a rapid and significant increase in Lagerhans' cell count immediately after treatment completion (21.17/mm2 and 25.94/mm2, respectively, at p = 0.019) which further increased in the group of complete response (in 9 subjects; 32.22/mm2). After transient elevation of the Langerhans' cell count it returned to a level even lower than initially in the non-responder group (4 subjects; 20.25/mm2). Our data strongly support the observation from static studies suggesting that regression of HPV-related cervical lesions is associated with increased density of epithelial Langerhans cells.

  20. DSMC Modeling of Flows with Recombination Reactions

    Science.gov (United States)

    2017-06-23

    rarefied gas dynamics community has seen the development of efficient algorithms for modern computer architectures16–19 which dramatically expand the area of...that participate in recombination. ACKNOWLEDGMENTS The work was supported by the Air Force Office of Sci - entific Research (Program Officer Dr. Ivett...flow,” Prog. Aerosp. Sci . 72, 66–79 (2015). 14R. D. Levine,Molecular Reaction Dynamics (Cambridge University Press, Cambridge, 2005). 15A. Alexeenko and

  1. Recombinant methods and materials

    Energy Technology Data Exchange (ETDEWEB)

    Roizman, B.; Post, L.E.

    1988-09-06

    This patent describes a method for stably effecting the insertion or deletion of a selected DNA sequence at a specific site in a viral genome. The method consists of: (1) isolating from the genome a linear DNA fragment comprising both (a) the specific site determined for insertion or deletion of selected DNA sequence and (b) flanking DNA sequences normally preceding and following the site; (2) preparing first and second altered genome fragments from the fragment isolated in step (1). (a) the first altered fragment comprising the fragment comprising a thymidine kinase gene in a position intermediate the ends of the fragment, and (b) the second altered fragment comprising the fragment having the selected DNA sequence inserted therein or deleted therefrom; (3) contacting the genome with the first altered fragment under conditions permitting recombination at sites of DNA sequence homology, selecting for a recombinant genome comprising the thymidine kinase gene, and isolating the recombinant genome; and (4) contacting the recombinant genome isolated in step (3) with the second altered fragment under conditions permitting recombination at sites of DNA sequence homology, selecting for a recombinant genome lacking the thymidine kinase gene, and isolating the recombinant genome product.

  2. Dissociative recombination in aeronomy

    Science.gov (United States)

    Fox, J. L.

    1989-01-01

    The importance of dissociative recombination in planetary aeronomy is summarized, and two examples are discussed. The first is the role of dissociative recombination of N2(+) in the escape of nitrogen from Mars. A previous model is updated to reflect new experimental data on the electronic states of N produced in this process. Second, the intensity of the atomic oxygen green line on the nightside of Venus is modeled. Use is made of theoretical rate coefficients for production of O (1S) in dissociative recombination from different vibrational levels of O2(+).

  3. Dissociation and recombination of D{sub 2} on Cu(111): Ab initio molecular dynamics calculations and improved analysis of desorption experiments

    Energy Technology Data Exchange (ETDEWEB)

    Nattino, Francesco, E-mail: f.nattino@chem.leidenuniv.nl; Genova, Alessandro; Guijt, Marieke; Kroes, Geert-Jan [Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden (Netherlands); Muzas, Alberto S.; Díaz, Cristina [Departamento de Química Módulo 13, Universitad Autónoma de Madrid, 28049 Madrid (Spain); Auerbach, Daniel J. [Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden (Netherlands); Max Planck Institute for Biophysical Chemistry, Göttingen (Germany)

    2014-09-28

    Obtaining quantitative agreement between theory and experiment for dissociative adsorption of hydrogen on and associative desorption of hydrogen from Cu(111) remains challenging. Particularly troubling is the fact that theory gives values for the high energy limit to the dissociative adsorption probability that is as much as two times larger than experiment. In the present work we approach this discrepancy in three ways. First, we carry out a new analysis of the raw experimental data for D{sub 2} associatively desorbing from Cu(111). We also perform new ab initio molecular dynamics (AIMD) calculations that include effects of surface atom motion. Finally, we simulate time-of-flight (TOF) spectra from the theoretical reaction probability curves and we directly compare them to the raw experimental data. The results show that the use of more flexible functional forms for fitting the raw TOF spectra gives fits that are in slightly better agreement with the raw data and in considerably better agreement with theory, even though the theoretical reaction probabilities still achieve higher values at high energies. The mean absolute error (MAE) for the energy E{sub 0} at which the reaction probability equals half the experimental saturation value is now lower than 1 kcal/mol, the limit that defines chemical accuracy, while a MAE of 1.5 kcal/mol was previously obtained. The new AIMD results are only slightly different from the previous static surface results and in slightly better agreement with experiment.

  4. Surface InP/In0.48Ga0.52P quantum dots: Carrier recombination dynamics and their interaction with fluorescent dyes

    Science.gov (United States)

    Hestroffer, Karine; Braun, Robert; Ugur, Asli; Tomm, Jens W.; Hackbarth, Steffen; Röder, Beate; Hatami, Fariba

    2013-10-01

    We describe the properties and carrier dynamics of surface InP quantum dots (QDs) on In0.48Ga0.52P, lattice-matched to GaAs (100). The structures were grown using gas-source molecular beam epitaxy. The average height and lateral size of the dots are in the range of 2-6 and 30-50 nm, respectively. The photoluminescence of the surface dots peaks between 750 and 830 nm, depending on the growth conditions, and is red-shifted compared to the emission of the capped QDs grown under similar conditions. The integrated photoluminescence intensity is comparable to that of the capped QDs. The decay time of both surface and capped QDs is around 1 ns at 15 K. The strong luminescence of surface QDs is explained by the effect of acting vacuum/air as an effective barrier and saturated surface states. Enhancement of the QDs luminescence is observed for the samples coated with a fluorescent dye.

  5. Dynamical origin of the electroweak scale and the 125 GeV scalar

    Directory of Open Access Journals (Sweden)

    Stefano Di Chiara

    2015-11-01

    Full Text Available We consider a fully dynamical origin for the masses of weak gauge bosons and heavy quarks of the Standard Model. Electroweak symmetry breaking and the gauge boson masses arise from new strong dynamics, which leads to the appearance of a composite scalar in the spectrum of excitations. In order to generate mass for the Standard Model fermions, we consider extended gauge dynamics, effectively represented by four fermion interactions at presently accessible energies. By systematically treating these interactions, we show that they lead to a large reduction of the mass of the scalar resonance. Therefore, interpreting the scalar as the recently observed 125 GeV state implies that the mass originating solely from new strong dynamics can be much heavier, i.e. of the order of 1 TeV. In addition to reducing the mass of the scalar resonance, we show that the four-fermion interactions allow for contributions to the oblique corrections in agreement with the experimental constraints. The couplings of the scalar resonance with the Standard Model gauge bosons and fermions are evaluated, and found to be compatible with the current LHC results. Additional new resonances are expected to be heavy, with masses of the order of a few TeVs, and hence accessible in future experiments.

  6. Novel intragenotype recombination in sapovirus.

    Science.gov (United States)

    Phan, Tung Gia; Yan, Hainian; Khamrin, Pattara; Quang, Trinh Duy; Dey, Shuvra Kanti; Yagyu, Fumihiro; Okitsu, Shoko; Müller, Werner E G; Ushijima, Hiroshi

    2006-01-01

    Based on the genetic analysis, a novel, naturally occurring recombination between two distinct sapovirus subtypes (subtype a and subtype b) within genogroup I genotype 1 was identified. Breakpoint analysis of recombinant sapovirus showed that the recombination site was at the polymerase-capsid junction. This is the first report of the existence of acute gastroenteritis caused by intragenotype recombinant sapovirus. The results also provided evidence that the natural recombination occurs not only in sapovirus genogroup II but also in sapovirus genogroup I.

  7. Recombination accelerates adaptation on a large-scale empirical fitness landscape in HIV-1.

    Science.gov (United States)

    Moradigaravand, Danesh; Kouyos, Roger; Hinkley, Trevor; Haddad, Mojgan; Petropoulos, Christos J; Engelstädter, Jan; Bonhoeffer, Sebastian

    2014-06-01

    Recombination has the potential to facilitate adaptation. In spite of the substantial body of theory on the impact of recombination on the evolutionary dynamics of adapting populations, empirical evidence to test these theories is still scarce. We examined the effect of recombination on adaptation on a large-scale empirical fitness landscape in HIV-1 based on in vitro fitness measurements. Our results indicate that recombination substantially increases the rate of adaptation under a wide range of parameter values for population size, mutation rate and recombination rate. The accelerating effect of recombination is stronger for intermediate mutation rates but increases in a monotonic way with the recombination rates and population sizes that we examined. We also found that both fitness effects of individual mutations and epistatic fitness interactions cause recombination to accelerate adaptation. The estimated epistasis in the adapting populations is significantly negative. Our results highlight the importance of recombination in the evolution of HIV-I.

  8. Regulation of Meiotic Recombination

    Energy Technology Data Exchange (ETDEWEB)

    Gregory p. Copenhaver

    2011-11-09

    Meiotic recombination results in the heritable rearrangement of DNA, primarily through reciprocal exchange between homologous chromosome or gene conversion. In plants these events are critical for ensuring proper chromosome segregation, facilitating DNA repair and providing a basis for genetic diversity. Understanding this fundamental biological mechanism will directly facilitate trait mapping, conventional plant breeding, and development of genetic engineering techniques that will help support the responsible production and conversion of renewable resources for fuels, chemicals, and the conservation of energy (1-3). Substantial progress has been made in understanding the basal recombination machinery, much of which is conserved in organisms as diverse as yeast, plants and mammals (4, 5). Significantly less is known about the factors that regulate how often and where that basal machinery acts on higher eukaryotic chromosomes. One important mechanism for regulating the frequency and distribution of meiotic recombination is crossover interference - or the ability of one recombination event to influence nearby events. The MUS81 gene is thought to play an important role in regulating the influence of interference on crossing over. The immediate goals of this project are to use reverse genetics to identify mutants in two putative MUS81 homologs in the model plant Arabidopsis thaliana, characterize those mutants and initiate a novel forward genetic screen for additional regulators of meiotic recombination. The long-term goal of the project is to understand how meiotic recombination is regulated in higher eukaryotes with an emphasis on the molecular basis of crossover interference. The ability to monitor recombination in all four meiotic products (tetrad analysis) has been a powerful tool in the arsenal of yeast geneticists. Previously, the qrt mutant of Arabidopsis, which causes the four pollen products of male meiosis to remain attached, was developed as a facile system

  9. Dynamical parton distributions from DGLAP equations with nonlinear corrections

    CERN Document Server

    Wang, Rong

    2016-01-01

    Determination of proton parton distribution functions is present under the dynamical parton model assumption by applying DGLAP equations with GLR-MQ-ZRS corrections. We provide two data sets, referred as IMParton16, which are from two different nonperturbative inputs. One is the naive three valence quarks input and the other is three valence quarks with flavor-asymmetric sea components input. Basically, both data sets are compatible with the experimental measurements at high scale ($Q^2>2$ GeV$^2$). Furthermore, our analysis shows that the input with flavor-asymmetric sea components better reproduce the structure functions at high $Q^2$. Generally, the obtained parton distribution functions, especially the gluon distribution functions, are the good options of inputs for simulations of high energy scattering processes. The analysis is performed under the fixed-flavor number scheme for $n_f=$ 3, 4, 5 and uses the $\\overline{\\text MS}$ scheme for the running coupling $\\alpha_s$ and the heavy-quark masses. Both d...

  10. Charmed Tetraquarks Tcc and Tcs from Dynamical Lattice QCD Simulations

    CERN Document Server

    Ikeda, Yoichi; Aoki, Sinya; Doi, Takumi; Hatsuda, Tetsuo; Inoue, Takashi; Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji

    2013-01-01

    Charmed tetraquarks $T_{cc}=(cc\\bar{u}\\bar{d})$ and $T_{cs}=(cs\\bar{u}\\bar{d})$ are studied through the S-wave meson-meson interactions, $D$-$D$, $\\bar{K}$-$D$, $D$-$D^{*}$ and $\\bar{K}$-$D^{*}$, on the basis of the (2+1)-flavor lattice QCD simulations with the pion mass $m_{\\pi} \\simeq $410, 570 and 700 MeV. For the charm quark, the relativistic heavy quark action is employed to treat its dynamics on the lattice. Using the HAL QCD method, we extract the S-wave potentials in lattice QCD simulations, from which the meson-meson scattering phase shifts are calculated. The phase shifts in the isospin triplet ($I$=1) channels indicate repulsive interactions, while those in the $I=0$ channels suggest attraction, growing as $m_{\\pi}$ decreases. This is particularly prominent in the $T_{cc} (J^P=1^+,I=0)$ channel, though neither bound state nor resonance are found in the range $m_{\\pi} =410-700$ MeV. We make a qualitative comparison of our results with the phenomenological diquark picture.

  11. Charmed tetraquarks Tcc and Tcs from dynamical lattice QCD simulations

    Science.gov (United States)

    Ikeda, Yoichi; Charron, Bruno; Aoki, Sinya; Doi, Takumi; Hatsuda, Tetsuo; Inoue, Takashi; Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji

    2014-02-01

    Charmed tetraquarks Tcc=(ccubardbar) and Tcs=(csubardbar) are studied through the S-wave meson-meson interactions, D-D, Kbar-D, D-D* and Kbar-D*, on the basis of the (2+1)-flavor lattice QCD simulations with the pion mass mπ≃410, 570 and 700 MeV. For the charm quark, the relativistic heavy quark action is employed to treat its dynamics on the lattice. Using the HAL QCD method, we extract the S-wave potentials in lattice QCD simulations, from which the meson-meson scattering phase shifts are calculated. The phase shifts in the isospin triplet (I=1) channels indicate repulsive interactions, while those in the I=0 channels suggest attraction, growing as mπ decreases. This is particularly prominent in the Tcc (JP=1+,I=0) channel, though neither bound state nor resonance are found in the range mπ=410-700 MeV. We make a qualitative comparison of our results with the phenomenological diquark picture.

  12. Intergenogroup Recombination in Sapoviruses

    Science.gov (United States)

    Hansman, Grant S.; Takeda, Naokazu; Oka, Tomoichiro; Oseto, Mitsukai; Hedlund, Kjell-Olof

    2005-01-01

    Sapovirus, a member of the family Caliciviridae, is an etiologic agent of gastroenteritis in humans and pigs. Analyses of the complete genome sequences led us to identify the first sapovirus intergenogroup recombinant strain. Phylogenetic analysis of the nonstructural region (i.e., genome start to capsid start) grouped this strain into genogroup II, whereas the structural region (i.e., capsid start to genome end) grouped this strain into genogroup IV. We found that a recombination event occurred at the polymerase and capsid junction. This is the first report of intergenogroup recombination for any calicivirus and highlights a possible route of zoonoses because sapovirus strains that infect pig species belong to genogroup III. PMID:16485479

  13. Recombination experiments at CRYRING

    Energy Technology Data Exchange (ETDEWEB)

    Spies, W.; Glans, P.; Zong, W.; Gao, H.; Andler, G.; Justiniano, E.; Saito, M.; Schuch, R

    1998-11-15

    Recent advances in studies of electron-ion recombination processes at low relative energies with the electron cooler of the heavy-ion storage ring CRYRING are shown. Through the use of an adiabatically expanded electron beam, collisions down to 10{sup -4}eV relative energies were measured with highly charged ions stored in the ring at around 15 MeV/amu energies. Examples of recombination measurements for bare ions of D{sup +}, He{sup 2+}, N{sup 7+}, Ne{sup 10+} and Si{sup 14+} are presented. Further on, results of an experiment measuring laser-induced recombination (LIR) into n=3 states of deuterium with polarized laser light are shown.

  14. Recombinant Helicobacter pylori catalase

    Institute of Scientific and Technical Information of China (English)

    Yang Bai; Ya-Li Zhang; Jian-Feng Jin; Ji-De Wang; Zhao-Shan Zhang

    2003-01-01

    AIM: To construct a recombinant strain which highly expresses catalase of Helicobacter pylori(H.pylori) and assay the activity of H. pylori catalase.METHODS: The catalase DNA was amplified from H. pylori chromosomal DNA with PCR techniques and inserted into the prokaryotie expression vector pET-22b (+), and then was transformed into the BL21 (DE3) E. coli strain which expressed catalase recombinant protein. The activity of H.pylori catalase was assayed by the Beers & Sizers.RESULTS: DNA sequence analysis showed that the sequence of catalase DNA was the same as GenBank's research. The catalase recombinant protein amounted to 24.4 % of the total bacterial protein after induced with IPTG for 3 hours at 37 ℃ and the activity of H. pylori catalase was high in the BL21 (DE3) E. coli strain.CONCLUSION: A clone expressing high activity H. pylori catalase is obtained, laying a good foundation for further studies.

  15. Heavy Hadrons in Dense Matter

    CERN Document Server

    Tolos, Laura; Hidalgo-Duque, Carlos; Nieves, Juan; Romanets, Olena; Salcedo, Lorenzo Luis; Torres-Rincon, Juan M

    2015-01-01

    We study the behavior of dynamically-generated baryon resonances with heavy-quark content within a unitarized coupled-channel theory in matter that fulfills heavy-quark spin symmetry constraints. We analyze the implications for the formation of charmed mesic nuclei and the propagation of heavy mesons in heavy-ion collisions from RHIC to FAIR.

  16. Recombineering linear BACs.

    Science.gov (United States)

    Chen, Qingwen; Narayanan, Kumaran

    2015-01-01

    Recombineering is a powerful genetic engineering technique based on homologous recombination that can be used to accurately modify DNA independent of its sequence or size. One novel application of recombineering is the assembly of linear BACs in E. coli that can replicate autonomously as linear plasmids. A circular BAC is inserted with a short telomeric sequence from phage N15, which is subsequently cut and rejoined by the phage protelomerase enzyme to generate a linear BAC with terminal hairpin telomeres. Telomere-capped linear BACs are protected against exonuclease attack both in vitro and in vivo in E. coli cells and can replicate stably. Here we describe step-by-step protocols to linearize any BAC clone by recombineering, including inserting and screening for presence of the N15 telomeric sequence, linearizing BACs in vivo in E. coli, extracting linear BACs, and verifying the presence of hairpin telomere structures. Linear BACs may be useful for functional expression of genomic loci in cells, maintenance of linear viral genomes in their natural conformation, and for constructing innovative artificial chromosome structures for applications in mammalian and plant cells.

  17. Recombinant DNA for Teachers.

    Science.gov (United States)

    Duvall, James G., III

    1992-01-01

    A science teacher describes his experience at a workshop to learn to teach the Cold Spring Harbor DNA Science Laboratory Protocols. These protocols lead students through processes for taking E. coli cells and transforming them into a new antibiotic resistant strain. The workshop featured discussions of the role of DNA recombinant technology in…

  18. Recombinant renewable polyclonal antibodies.

    Science.gov (United States)

    Ferrara, Fortunato; D'Angelo, Sara; Gaiotto, Tiziano; Naranjo, Leslie; Tian, Hongzhao; Gräslund, Susanne; Dobrovetsky, Elena; Hraber, Peter; Lund-Johansen, Fridtjof; Saragozza, Silvia; Sblattero, Daniele; Kiss, Csaba; Bradbury, Andrew R M

    2015-01-01

    Only a small fraction of the antibodies in a traditional polyclonal antibody mixture recognize the target of interest, frequently resulting in undesirable polyreactivity. Here, we show that high-quality recombinant polyclonals, in which hundreds of different antibodies are all directed toward a target of interest, can be easily generated in vitro by combining phage and yeast display. We show that, unlike traditional polyclonals, which are limited resources, recombinant polyclonal antibodies can be amplified over one hundred million-fold without losing representation or functionality. Our protocol was tested on 9 different targets to demonstrate how the strategy allows the selective amplification of antibodies directed toward desirable target specific epitopes, such as those found in one protein but not a closely related one, and the elimination of antibodies recognizing common epitopes, without significant loss of diversity. These recombinant renewable polyclonal antibodies are usable in different assays, and can be generated in high throughput. This approach could potentially be used to develop highly specific recombinant renewable antibodies against all human gene products.

  19. SUMO Wrestles with Recombination

    Directory of Open Access Journals (Sweden)

    Lumír Krejčí

    2012-07-01

    Full Text Available DNA double-strand breaks (DSBs comprise one of the most toxic DNA lesions, as the failure to repair a single DSB has detrimental consequences on the cell. Homologous recombination (HR constitutes an error-free repair pathway for the repair of DSBs. On the other hand, when uncontrolled, HR can lead to genome rearrangements and needs to be tightly regulated. In recent years, several proteins involved in different steps of HR have been shown to undergo modification by small ubiquitin-like modifier (SUMO peptide and it has been suggested that deficient sumoylation impairs the progression of HR. This review addresses specific effects of sumoylation on the properties of various HR proteins and describes its importance for the homeostasis of DNA repetitive sequences. The article further illustrates the role of sumoylation in meiotic recombination and the interplay between SUMO and other post-translational modifications.

  20. Recombinant Human Enterovirus 71

    OpenAIRE

    2004-01-01

    Two human enterovirus 71 (HEV71) isolates were identified from hand, foot and mouth disease patients with genome sequences that had high similarity to HEV71 (>93%) at 5´ UTR, P1, and P2 and coxsackievirus A16 (CV-A16, >85%) at P3 and 3´UTR. Intertypic recombination is likely to have occurred between HEV71 and CV-A16 or an as-yet to be described CV-A16-like virus.

  1. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  2. Recombinant human milk proteins.

    Science.gov (United States)

    Lönnerdal, Bo

    2006-01-01

    Human milk provides proteins that benefit newborn infants. They not only provide amino acids, but also facilitate the absorption of nutrients, stimulate growth and development of the intestine, modulate immune function, and aid in the digestion of other nutrients. Breastfed infants have a lower prevalence of infections than formula-fed infants. Since many women in industrialized countries choose not to breastfeed, and an increasing proportion of women in developing countries are advised not to breastfeed because of the risk of HIV transmission, incorporation of recombinant human milk proteins into infant foods is likely to be beneficial. We are expressing human milk proteins known to have anti-infective activity in rice. Since rice is a normal constituent of the diet of infants and children, limited purification of the proteins is required. Lactoferrin has antimicrobial and iron-binding activities. Lysozyme is an enzyme that is bactericidal and also acts synergistically with lactoferrin. These recombinant proteins have biological activities identical to their native counterparts. They are equally resistant to heat processing, which is necessary for food applications, and to acid and proteolytic enzymes which are needed to maintain their biological activity in the gastrointestinal tract of infants. These recombinant human milk proteins may be incorporated into infant formulas, baby foods and complementary foods, and used with the goal to reduce infectious diseases.

  3. Evolution of recombination in eutherian mammals: insights into mechanisms that affect recombination rates and crossover interference.

    Science.gov (United States)

    Segura, Joana; Ferretti, Luca; Ramos-Onsins, Sebastián; Capilla, Laia; Farré, Marta; Reis, Fernanda; Oliver-Bonet, Maria; Fernández-Bellón, Hugo; Garcia, Francisca; Garcia-Caldés, Montserrat; Robinson, Terence J; Ruiz-Herrera, Aurora

    2013-11-22

    Recombination allows faithful chromosomal segregation during meiosis and contributes to the production of new heritable allelic variants that are essential for the maintenance of genetic diversity. Therefore, an appreciation of how this variation is created and maintained is of critical importance to our understanding of biodiversity and evolutionary change. Here, we analysed the recombination features from species representing the major eutherian taxonomic groups Afrotheria, Rodentia, Primates and Carnivora to better understand the dynamics of mammalian recombination. Our results suggest a phylogenetic component in recombination rates (RRs), which appears to be directional, strongly punctuated and subject to selection. Species that diversified earlier in the evolutionary tree have lower RRs than those from more derived phylogenetic branches. Furthermore, chromosome-specific recombination maps in distantly related taxa show that crossover interference is especially weak in the species with highest RRs detected thus far, the tiger. This is the first example of a mammalian species exhibiting such low levels of crossover interference, highlighting the uniqueness of this species and its relevance for the study of the mechanisms controlling crossover formation, distribution and resolution.

  4. Bacterial Recombineering: Genome Engineering via Phage-Based Homologous Recombination.

    Science.gov (United States)

    Pines, Gur; Freed, Emily F; Winkler, James D; Gill, Ryan T

    2015-11-20

    The ability to specifically modify bacterial genomes in a precise and efficient manner is highly desired in various fields, ranging from molecular genetics to metabolic engineering and synthetic biology. Much has changed from the initial realization that phage-derived genes may be employed for such tasks to today, where recombineering enables complex genetic edits within a genome or a population. Here, we review the major developments leading to recombineering becoming the method of choice for in situ bacterial genome editing while highlighting the various applications of recombineering in pushing the boundaries of synthetic biology. We also present the current understanding of the mechanism of recombineering. Finally, we discuss in detail issues surrounding recombineering efficiency and future directions for recombineering-based genome editing.

  5. Oxygen Atom Recombination in Carbon Dioxide Atmospheres

    Science.gov (United States)

    Jamieson, Corey; Garcia, R. M.; Pejakovic, D. A.; Kalogerakis, K. S.

    2009-09-01

    Understanding processes involving atomic oxygen is crucial for the study and modeling of composition, energy transfer, airglow, and transport dynamics in planetary atmospheres. Significant gaps and uncertainties exist in our understanding of the above processes, and often the relevant input from laboratory measurements is missing or outdated. We are conducting experiments to measure the rate coefficients for O + O + CO2 and O + O2 + CO2 recombination and investigate the O2 excited states produced following O-atom recombination. These laboratory measurements are key input for a quantitative understanding and reliable modeling of the atmospheres of the CO2 planets and their airglow. An ArF excimer laser with 193-nm pulsed output radiation is employed to partially photodissociate carbon dioxide. In an ambient-pressure (760 Torr) background of CO2, the O atoms produced recombine in a time scale of a few milliseconds. Detection of laser-induced fluorescence at 845 nm following two-photon excitation near 226 nm monitors the decay of the oxygen atom population. From the temporal evolution of the signal we can extract the rate coefficients for recombination of O + O and O + O2 in the presence of CO2. We also use fluorescence and resonance-enhanced multi-photon ionization techniques to detect the products of the O-atom recombination and subsequent relaxation in CO2. This work is supported by the US National Science Foundation's (NSF) Planetary Astronomy Program. Rosanne Garcia's participation was funded by the NSF Research Experiences for Undergraduates (REU) Program.

  6. Recombinant Collagenlike Proteins

    Science.gov (United States)

    Fertala, Andzej

    2007-01-01

    A group of collagenlike recombinant proteins containing high densities of biologically active sites has been invented. The method used to express these proteins is similar to a method of expressing recombinant procollagens and collagens described in U. S. Patent 5,593,859, "Synthesis of human procollagens and collagens in recombinant DNA systems." Customized collagenous proteins are needed for biomedical applications. In particular, fibrillar collagens are attractive for production of matrices needed for tissue engineering and drug delivery. Prior to this invention, there was no way of producing customized collagenous proteins for these and other applications. Heretofore, collagenous proteins have been produced by use of such biological systems as yeasts, bacteria, and transgenic animals and plants. These products are normal collagens that can also be extracted from such sources as tendons, bones, and hides. These products cannot be made to consist only of biologically active, specific amino acid sequences that may be needed for specific applications. Prior to this invention, it had been established that fibrillar collagens consist of domains that are responsible for such processes as interaction with cells, binding of growth factors, and interaction with a number of structural proteins present in the extracellular matrix. A normal collagen consists of a sequence of domains that can be represented by a corresponding sequence of labels, e.g., D1D2D3D4. A collagenlike protein of the present invention contains regions of collagen II that contain multiples of a single domain (e.g., D1D1D1D1 or D4D4D4D4) chosen for its specific biological activity. By virtue of the multiplicity of the chosen domain, the density of sites having that specific biological activity is greater than it is in a normal collagen. A collagenlike protein according to this invention can thus be made to have properties that are necessary for tissue engineering.

  7. Dielectronic recombination theory

    Energy Technology Data Exchange (ETDEWEB)

    LaGattuta, K.J.

    1991-12-31

    A theory now in wide use for the calculation of dielectronic recombination cross sections ({sigma}{sup DR}) and rate coefficients ({alpha}{sup DR}) was one introduced originally by Feshbach for nuclear physics applications, and then later adapted for atomic scattering problems by Hahn. In the following, we briefly review this theory in a very general form, which allows one to account for the effects of overlapping and interacting resonances, as well as continuum-continuum coupling. An extension of our notation will then also allow for the inclusion of the effects of direct radiative recombination, along with a treatment of the interference between radiative and dielectronic recombination. Other approaches to the calculation of {sigma}{sup DR} have been described by Fano and by Seaton. We will not consider those theories here. Calculations of {alpha}{sup DR} have progressed considerably over the last 25 years, since the early work of Burgess. Advances in the reliability of theoretical predictions have also been promoted recently b a variety of direct laboratory measurements of {sigma}{sup DR}. While the measurements of {sigma}{sup DR} for {delta}n {ne} 0 excitations have tended to agree very well with calculations, the case of {delta}n = 0 has been much problematic. However, by invoking a mechanism originally proposed by Jacobs, which takes into account the effect of stray electric fields on high Rydberg states (HRS) participating in the DR process, new calculations have improved the agreement between theory and experiment for these cases. Nevertheless, certain discrepancies still remain.

  8. Did the universe recombine

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, J.G.; Stebbins, A. (California, University, Berkeley (USA) Toronto, University (Canada))

    1991-04-01

    The Zel'dovich-Sunyaev model-independent arguments for the existence of a neutral hydrogen phase is reviewed in light of new limits on the Compton y parameter from COBE. It is concluded that with baryon densities compatible with standard cosmological nucleosynthesis, the universe could have remained fully ionized throughout its history without producing a detectable spectral distortion. It is argued that it is unlikely that spectral observations of the cosmic microwave background will ever require the universe to have recombined for flat cosmologies. 22 refs.

  9. Novel recombinant sapovirus in Bangladesh.

    Science.gov (United States)

    Dey, Shuvra Kanti; Mizuguchi, Masashi; Okitsu, Shoko; Ushijima, Hiroshi

    2011-01-01

    Recombination of RNA viruses plays an important part in molecular epidemiological study, virus evolution, vaccine design, and viral control programs. Sapovirus, a member of the family Caliciviridae, is one of the major causative agents of viral gastroenteritis affecting all age groups. Sapovirus capsid and polymerase regions were amplified by PCR using specific primers. PCR products were sequenced directly and sequence analysis was performed using CLUSTAL X, SimPlot, and MEGA 4 software package. Based on the genetic analysis, a novel, naturally occurring recombinant sapovirus strain was identified in Bangladesh. Breakpoint analysis of the recombinant sapovirus showed that the recombination site was at the open reading frame ORF1/ORF2 overlap. We described the genetic characterization of a novel, naturally occurring recombinant sapovirus and provided the first evidence of recombination in sapovirus in Bangladesh.

  10. Expression of recombinant antibodies.

    Science.gov (United States)

    Frenzel, André; Hust, Michael; Schirrmann, Thomas

    2013-01-01

    Recombinant antibodies are highly specific detection probes in research, diagnostics, and have emerged over the last two decades as the fastest growing class of therapeutic proteins. Antibody generation has been dramatically accelerated by in vitro selection systems, particularly phage display. An increasing variety of recombinant production systems have been developed, ranging from Gram-negative and positive bacteria, yeasts and filamentous fungi, insect cell lines, mammalian cells to transgenic plants and animals. Currently, almost all therapeutic antibodies are still produced in mammalian cell lines in order to reduce the risk of immunogenicity due to altered, non-human glycosylation patterns. However, recent developments of glycosylation-engineered yeast, insect cell lines, and transgenic plants are promising to obtain antibodies with "human-like" post-translational modifications. Furthermore, smaller antibody fragments including bispecific antibodies without any glycosylation are successfully produced in bacteria and have advanced to clinical testing. The first therapeutic antibody products from a non-mammalian source can be expected in coming next years. In this review, we focus on current antibody production systems including their usability for different applications.

  11. Dissociative recombination of HCl+

    Science.gov (United States)

    Larson, Åsa; Fonseca dos Santos, Samantha; E. Orel, Ann

    2017-08-01

    The dissociative recombination of HCl+, including both the direct and indirect mechanisms, is studied. For the direct process, the relevant electronic states are calculated ab initio by combining electron scattering calculations to obtain resonance positions and autoionization widths with multi-reference configuration interaction calculations of the ion and Rydberg states. The cross section for the direct dissociation along electronic resonant states is computed by solution of the time-dependent Schrödinger equation. For the indirect process, an upper bound value for the cross section is obtained using a vibrational frame transformation of the elements of the scattering matrix at energies just above the ionization threshold. Vibrational excitations of the ionic core from the ground vibrational state, v = 0 , to the first three excited vibrational states, v = 1 , v = 2 , and v = 3 , are considered. Autoionization is neglected and the effect of the spin-orbit splitting of the ionic potential energy upon the indirect dissociative recombination cross section is considered. The calculated cross sections are compared to measurements.

  12. Neutral MSSM Higgs-boson production with heavy quarks: NLO supersymmetric QCD corrections

    CERN Document Server

    Dittmaier, Stefan; Krämer, Michael; Spira, Michael; Walser, Manuel

    2014-01-01

    Within the minimal supersymmetric extension of the Standard Model (MSSM) the associated production of neutral Higgs bosons with top and bottom quarks belongs to the most important Higgs-boson production processes at the LHC. At large values of tan(beta), in particular, bottom--Higgs associated production constitutes the dominant production channel within the MSSM. We have calculated the next-to-leading-order supersymmetric QCD corrections to neutral Higgs production through the parton processes q qbar, gg -> t tbar / b bbar + h/H/A and present results for the total cross sections. The genuine SUSY-QCD corrections are of moderate size for small tan(beta), but can be sizable for large tan(beta). In the latter case the bulk of these corrections can be absorbed into effective bottom Yukawa couplings.

  13. Nuclear effects on heavy quark production. Results from Fermilab experiments E772 and E789

    Energy Technology Data Exchange (ETDEWEB)

    Leitch, M.J.; Alde, D.; Baer, H.; Boissevain, J.; Carey, T.; Garvey, G.T.; Jeppesen, R.; Kapustinsky, J.; Klein, A.; Lane, D.; Lee, C.; Lillberg, J.; McGaughey, P.; Moss, J.M.; Peng, J.C. (Los Alamos National Lab., NM (United States)); Brooks, M.; Brown, G.; Isenhower, D.; Sadler, M.; Schnathorst, R. (Abilene Christian Univ., TX (United States)); Danner, G.; Wang, M. (Case Western Reserve Univ., Cleveland, OH (United States)); Lederman, L.; Schub, M. (Univ. of Chicago, IL (United States)); Brown, C.N.; Cooper, W.E.; Glass, H.; Hsiung, Y.B.; Mishra, C.S.; Gounder, K. (Fermilab, Batavia, IL (United States)); Adams, M.R. (Univ. of Illinois, Chicago, IL (United States)); Gidal, G.; Ho, P.M.; Kowitt, M.; Luk, K.B.; Pripstein, D. (Lawrence Berkeley Lab., CA (United States)); Apolinski, M.; Guo, R.; Kaplan, D.M.; Martin, V.; Preston, R.; Sa, J.; Tanikella, V. (Northern Illinois Univ., DeKalb, IL (United States)); Childers, R.; Darden, C.; Wilson, J. (Univ. of South Carolina, Columbia; E772 and E789 Collaborations

    1992-07-20

    Fermilab Experiments E772 and E789 are fixed target experiments with 800 GeV protons incident on nuclear targets corresponding to a center-of-mass energy of [radical]s [approx equal] 39 GeV. Measurements are made with a pair spectrometer which has a solid angle of a few percent and operates at high luminosity with up to [approx equal] 10[sup 12](E772) or [approx equal] 10[sup 11](E789) protons/spill. Our experimental program explores several types of nuclear medium effects: the modification of quark and gluon structure functions by the nucleus, effects on the production of vector mesons (e.g. J/[psi] and [Upsilon]), and effects on the production of D mesons. (orig.).

  14. Heavy quark spectroscopy and matrix elements: A lattice study using the static approximation

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, A.K.; Flynn, J.M.; Sachrajda, C.T.; Stella, N.; Wittig, H. [Physics Department, The University, Southampton SO17 1BJ (United Kingdom); Bowler, K.C.; Kenway, R.D.; Mehegan, J.; Richards, D.G. [Department of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3JZ (Scotland); Michael, C. [DAMTP, University of Liverpool, Liverpool L69 3BX, United Kingdom (UKQCD Collaboration)

    1996-09-01

    We present results of a lattice analysis of the {ital B} parameter {ital B}{sub {ital B}}, the decay constant {ital f}{sub {ital B}}, and several mass splittings using the static approximation. Results were obtained for 60 quenched gauge configurations computed at {beta}=6.2 on a lattice size of 24{sup 3}{times}48. Light quark propagators were calculated using the {ital O}({ital a})-improved Sheikholeslami-Wohlert action. We find {ital B}{sub {ital B}}{sup static}({ital m}{sub {ital b}})=0.69{sub {minus}4}{sup +3}(stat){sub {minus}1}{sup +2} (syst), corresponding to {ital B}{sub {ital B}}{sup static}=1.02{sub {minus}6 {minus}2}{sup +5 +3}, {ital f}{sub {ital B}}{sup static}=266{sub {minus}20 {minus}27}{sup +18 +28} MeV, and {ital f}{sub {ital B}}{sub {ital s}}{sup 2}{ital B}{sub {ital B}}{sub {ital s}}/{ital f}{sub {ital B}}{ital i}{sup 2}{ital B}{sub {ital B}}=1.34{sub {minus}8 {minus}3}{sup +9 +5}, where a variational fitting technique was used to extract {ital f}{sup 2}{sub {ital B{sub s}}}{ital B}{sub {ital B{sub {ital s}}}}{sub B{sup static}}. For the mass splittings we obtain {ital M}{sub {ital B{sub {ital s}}}}{minus}{ital M}{sub {ital B{sub {ital d}}}}=87{sub {minus}12 {minus}12}{sup +15 +6} MeV, {ital M}{sub {Lambda}{sub {ital b}}}{minus}{ital M}{sub {ital B}}{sub {ital d}}=420{sub {minus}90 {minus}30}{sup +100 +30} MeV, and {ital M}{sub {ital B}{asterisk}}{sup 2}{minus}{ital M}{sup 2}{sub {ital B}}=0.281{sub {minus}16 {minus}37}{sup +15 +40} GeV{sup 2}. We compare different smearing techniques intended to improve the signal/noise ratio. From a detailed assessment of systematic effects, we conclude that the main systematic uncertainties are associated with the renormalization constants relating a lattice matrix element to its continuum counterpart. The dependence of our findings on lattice artifacts is to be investigated in the future. {copyright} {ital 1996 The American Physical Society.}

  15. Recent relativistic heavy ion collider results on photon, dilepton and heavy quark

    Indian Academy of Sciences (India)

    Frédéric Fleuret

    2009-01-01

    We present here a review of the recent results obtained by the RHIC experiments in the framework of QCD under extreme conditions of high temperature or large baryon density, the so-called quark gluon plasma. We focus on a specific category of observables: the electromagnetic probes which cover a large spectrum of experimental studies.

  16. Nuclear effects on heavy quark production: Results from Fermilab Experiments E772 and E789

    Energy Technology Data Exchange (ETDEWEB)

    E772 and E789 Collaborations

    1991-12-31

    Fermilab Experiments E772 and E789 are fixed target experiments with 800 GeV protons incident on nuclear targets corresponding to a center-of-mass energy of {radical}{bar s} {approximately} 39 GeV. Measurements are made with a pair spectrometer which has a solid angle of a few percent and operates at high luminosity with up to {approximately}10{sup 12}(E772) or {approximately}10{sup 11}(E789) protons/spill. Our experimental program explores several types of nuclear medium effects: the modification of quark and gluon structure functions by the nucleus, effects on the production of vector mesons (e.g. J/{psi} and {gamma}), and effects on the production of D mesons. The latter is accomplished with the use of a new silicon vertex detector. E789 also looks at the decays of B mesons including the decay to J/{psi} and searches for the decays to two-charged particles (e.g. B {yields} h{sup +}h{sup {minus}}) but I will not discuss this part of our program in this paper.

  17. Heavy quark pair production in high energy pA collisions: Open heavy flavors

    CERN Document Server

    Fujii, Hirotsugu

    2013-01-01

    We study open heavy flavor meson production in proton-nucleus (pA) collisions at RHIC and LHC energies within the Color Glass Condensate framework. We use the unintegrated gluon distribution at small Bjorken's x in the proton obtained by solving the Balitsky-Kovchegov equation with running coupling correction and constrained by global fitting of HERA data. We change the initial saturation scale of the gluon distribution for the heavy nucleus. The gluon distribution with McLerran-Venugopalan model initial condition is also used for comparison. We present transverse momentum spectra of single D and B productions in pA collisions, and the so-called nuclear modification factor. The azimuthal angle correlation of open heavy flavor meson pair is also computed to study the modification due to the gluon saturation in the heavy nucleus at the LHC.

  18. Heavy quark pair production in high energy pA collisions: Quarkonium

    CERN Document Server

    Fujii, Hirotsugu

    2013-01-01

    Quarkonium production in high-energy proton (deuteron)-nucleus collisions is investigated in the color glass condensate framework. We employ the color evaporation model assuming that the quark pair produced from dense small-x gluons in the nuclear target bounds into a quarkonium outside the target. The unintegrated gluon distribution at small Bjorken x in the nuclear target is treated with the Balitsky-Kovchegov equation with running coupling corrections. For the gluons in the proton, we examine two possible descriptions, unintegrated gluon distribution and ordinary collinear gluon distribution. We present the transverse momentum spectrum and nuclear modification factor for J/psi production at RHIC and LHC energies, and those for Upsilon(1S) at LHC energy, and discuss the nuclear modification factor and the momentum broadening by changing the rapidity and the initial saturation scale.

  19. X(3872 in Heavy Quark Limit of QCD: Its Partners and Isospin Structure

    Directory of Open Access Journals (Sweden)

    Ozpineci A.

    2014-01-01

    Full Text Available Although it has been more than ten years since the discovery of the X(3872 meson, its properties still contain puzzles. In this work, the results obtained using a correlation function approach on the degenerate partners of the X(3872 will be presented. The isospin structure is also discussed in the same framework. Finally, the X(3872 → D0 D̄0 π decay is proposed to study the isospin structure of the X(3872 meson.

  20. On the form factors of semileptonic baryon decays in Heavy Quark Effective Theory

    CERN Document Server

    Jugeau, Frederic

    2012-01-01

    We study consequences of the non-forward amplitude for the semileptonic baryon decay Lambda_b into Lambda_c which will be measured in detail at LHCb. We obtain a sum rule for the subleading elastic Isgur-Wise (IW) function A(w) that originates from the kinetic part of the O(1/mQ) effective Lagrangian perturbation. In the sum rule appear only the intermediate states J^P=1/2+, the same that contribute to the O(1/mQ)^2 correction to the axial-vector form factor G1(w) involved in the differential decay rate at zero recoil w=1. This allows us to obtain a lower bound on the correction -delta^(G1)_(1/mQ^2) in terms of A(w) and the shape of the leading elastic IW function xi(w). Another theoretical implication is that A'(1) must vanish in the limit where the slope of the xi(w) saturates its lower bound. A strong correlation between the leading IW function and the subleading one A(w) is thus established in the case of the baryons.

  1. Magnetic Moments of Baryons containing all heavy quarks in Quark-Diquark Model

    CERN Document Server

    Thakkar, Kaushal; Vinodkumar, P C

    2016-01-01

    The triply heavy flavour baryons are studied using the Quark-diquark description of the three-body system. The confinement potential for present study of triply heavy flavour baryons is assumed as coulomb plus power potential with power index $\

  2. A Comment on Conical Flow Induced by Heavy-Quark Jets

    CERN Document Server

    Antinori, F; Shuryak, ~E.V.

    2005-01-01

    The suppression of high transverse momentum particles, recently discovered at RHIC, is commonly interpreted as due to parton energy loss. In high energy nuclear collisions, QCD jets would deposit a large fraction of their energy and into the produced matter. The question of how this energy is degraded and whether we can use this phenomenon to probe the properties of the produced matter is now under active discussion. It has been proposed that if this matter, which is now being referred to as a {\\em strongly coupled Quark-Gluon Plasma} (sQGP), may behave as a liquid with a very small viscosity. In this case, a very specific collective excitation should be produced, called the ``conical flow'', similar e.g. to the sonic booms generated by the shock waves produced by supersonic planes. The RHIC experiments seem indeed to be obtaining some indication that the production of particles emitted opposite to a high-$p_t$ jet may actually be peaked away from the quenched jet direction, at an angle roughly consistent wit...

  3. Small-x physics and heavy quark photoproduction in the semihard approach at HERA

    CERN Document Server

    Saleev, V A; Saleev, A; Zotov, N P

    1995-01-01

    Processes of hevy quark photoproduction at HERA energies and beyond are investigated using the semihard (k_{\\bot} factorization) approach. The virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small x have been taken into account. The total cross sections, rapidity and p_{\\bot} distributions of the charm and beauty quark photoproduction have been calculated. We obtained the some differences between the predictions of the standard parton model and the semihard approach used here.

  4. Leptons from heavy-quark semileptonic decay in pA collisions within the CGC framework

    CERN Document Server

    Fujii, Hirotsugu

    2015-01-01

    We study single lepton production from semileptonic decays of heavy flavor hadrons ($D,B\\rightarrow~l$) in pp and p$A$ collisions at RHIC and the LHC within the saturation/Color-Glass-Condensate (CGC) framework. Using the gluon distribution function obtained with the dipole amplitude, whose energy dependence is described by the Balitsky-Kovchegov equation with running coupling effect, we compute the transverse-momentum ($p_\\perp$) spectra of the lepton yields at mid and forward rapidities. We find that a large fraction of leptons at low $p_\\perp$ stems from the saturation regime of the incoming gluons in the target, especially in p$A$ collisions at the LHC. The resultant $p_\\perp$ spectra is slightly harder than the data, but the nuclear modification factor seems consistent with the data within some uncertainty. We also update the nuclear modification factors for J/$\\psi$ and $D$ meson at the LHC energy.

  5. Duality predictions for the production of heavy quark systems in QCD

    CERN Document Server

    Glück, M

    1978-01-01

    Using partonic semi-local duality ideas combined with QCD the authors derive absolute, parameter-free predictions for the cross sections of heavy quarkonia (J/ psi , psi ', Upsilon , Upsilon ', ...) production in purely hadronic collisions as well as in photoproduction processes. They also discuss 'open' charm (DD) production and show how the CERN SPS beam dump measurements at square root S=27.4 GeV can be naturally reconciled with the predictions of QCD; similarly the recent ISR data are in good agreement with QCD. (23 refs).

  6. Heavy-to-heavy quark decays at next-to-next-to-leading order

    Science.gov (United States)

    Pak, Alexey; Czarnecki, Andrzej

    2008-12-01

    Details of a recent calculation of O(αs2) corrections to the decay b→cℓνl, taking into account the c-quark mass, are described. Construction of the expansion in the mass ratio mc/mb as well as the evaluation of new four-loop master integrals are presented. The same techniques are applicable to the muon decay, μ→eνμν¯e. Analytical results are presented, for the physical cases as well as for a model with purely-vector couplings.

  7. Heavy quark and neutrino physics. Final technical report, FY1994--FY1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This report begins with an overview of KSU history in personnel and funding, creation of infrastructure, and physics. Then brief summaries are given for the following research projects: Fermilab E653: Measuring Charm and Beauty Decays via Hadronic Production in a Hybrid Emulsion Spectrometer; Fermilab E791: Continued Study of Heavy Flavors at TPL; Fermilab E815: Precision Measurements of Neutrino Neutral-Current Interactions Using a Sign-Selected Beam; Fermilab E872/DONUT: Direct Observation of {nu}{sub {tau}}; Fermilab E803/COSMOS: Neutrino Oscillations; KSU at the Fermilab D0 collider; Muon Collider; OJI Progress Report: Multisampling Drift Chamber.

  8. Gluon bremsstrahlung by heavy quarks - its effects on transport coefficients and equilibrium distribution

    CERN Document Server

    Mazumder, Surasree; Alam, Jan-e

    2014-01-01

    The effects of gluon radiation by charm quarks on the transport coefficients {\\it e.g.} drag, longitudinal and transverse diffusion and shear viscosity have been studied within the ambit of perturbative quantum chromodynamics (pQCD) and kinetic theory. We found that while the soft gluon radiation has substantial effects on the transport coefficients of the charm quarks in the quark gluon plasma its effects on the equilibrium distribution function is insignificant.

  9. Prospects of heavy quark physics in run II with the D-Zero detector

    Energy Technology Data Exchange (ETDEWEB)

    Gounder, K.

    1998-09-01

    After a successful Run I, D0 is poised for an encore performance in Run II. This article summarizes the essential features of the D0 upgrade that involve a central magnetic field, a new tracking system, upgraded muon detection, and enhancements to muon, calorimeter and the data acquisition electronics. The goals for top quark physics for Run II are outlined along with issues affecting the precision measurement of top quark mass and single top quark production. The prospects and issues determining the B physics capabilities of D0 in Run II are addressed briefly and a study of the CP sensitivity in the mode B{sub d}{sup 0} {yields} J/{psi}K{sub s}{sup 0} is also presented.

  10. Z boson production in association with heavy quark jets at D0

    Energy Technology Data Exchange (ETDEWEB)

    Zennamo, III, Joseph Anthony [State Univ. of New York (SUNY), Buffalo, NY (United States)

    2013-10-28

    The dominant background in searches for a Higgs boson decaying into b-quarks at the Tevatron is production of a Z boson in association with either b- or c-quark initiated jets (b or c jets). This thesis describes the first measurements of the ratio of differential cross sections σ (Z + b jet)/ σ(Z + jet), and the first measurements of the ratio of cross sections σ (Z + c jet)/ σ(Z + jet) and σ (Z + c jet)/ σ(Z + b jet). These measurements are performed using the full D0 Run II data set corresponding to an integrated luminosity of 9.7 fb-1. The ratio of differential cross sections σ(Z + b jet)/σ (Z + jet) have been measured as a function of jet and Z boson pT , jet η , and Δφ(Z, jet). The Z+c jet ratios of differential cross sections are measured as a function of jet and Z boson pT .

  11. Charmonium dissociation and heavy quark transport in hot quenched lattice QCD

    CERN Document Server

    Ding, H -T; Kaczmarek, O; Karsch, F; Satz, H; Söldner, W

    2012-01-01

    We study the properties of charmonium states at finite temperature in quenched lattice QCD on large and fine isotropic lattices. We perform a detailed analysis of charmonium correlation and spectral functions both below and above Tc. Our analysis suggests that the S wave states disappear at about 1.5 Tc. The charm diffusion coefficient is estimated and found to be approximately 1/{\\pi}T at 1.5Tc {\\leq} T {\\leq} 3Tc.

  12. Heavy quark free energies for three quark systems at finite temperature

    CERN Document Server

    Hübner, K; Kaczmarek, O; Vogt, O

    2007-01-01

    We study the free energy of static three quark systems in singlet, octet, decuplet and average color channels in the quenched approximation and in 2-flavor QCD at finite temperature. We show that in the high temperature phase singlet and decuplet free energies of three quark systems are well described by the sum of the free energies of three diquark systems plus self energy contributions of the three quarks. In the confining low temperature phase we find evidence for a Y-shaped flux tube in SU(3) pure gauge theory, which is less evident in 2-flavor QCD due to the onset of string breaking. We also compare the short distance behavior of octet and decuplet free energies to the free energies of single static quarks in the corresponding color representations.

  13. Charmonium dissociation and heavy quark transport in hot quenched lattice QCD

    Directory of Open Access Journals (Sweden)

    Ding H.-T.

    2014-04-01

    Full Text Available We study the properties of charmonium states at finite temperature in quenched lattice QCD on large and fine isotropic lattices. We perform a detailed analysis of charmonium correlation and spectral functions both below and above Tc. Our analysis suggests that the S wave states disappear at about 1.5 Tc. The charm diffusion coeffcient is estimated and found to be approximately 1/πT at 1.5Tc ≲ T ≲ 3Tc.

  14. pQCD versus AdS/CFT tested by heavy quark energy loss

    Science.gov (United States)

    Horowitz, W. A.

    2008-04-01

    We predict the charm and bottom quark nuclear modification factors using weakly coupled perturbative quantum chromodynamics (pQCD) and strongly coupled AdS/CFT drag methods. The log(pT/MQ)/pT dependence of pQCD loss and the momentum independence of drag loss lead to different momentum dependences for the RAA predictions. This difference is enhanced by examining a new experimental observable, the double ratio of charm to bottom nuclear modification factors, Rcb = RcAA/RbAA. At LHC the weakly coupled theory predicts Rcb → 1, whereas the strongly coupled theory predicts Rcb ~ 0.2 independent of pT. At RHIC the differences are less dramatic, as the production spectra are harder, but the drag formula is applicable to higher momenta, due to the lower medium temperature.

  15. Testing AdS/CFT drag and pQCD heavy quark energy loss

    Science.gov (United States)

    Horowitz, W. A.; Gyulassy, M.

    2008-10-01

    We present charm and bottom nuclear modification factors for RHIC and LHC using standard model perturbative QCD and recent AdS/CFT string drag energy loss models. We find that extreme extrapolations to LHC mask potential experimentally determinable differences in the individual RAAs but that their ratio, RcAA/RbAA, as a function of transverse momentum is a remarkably robust observable for finding deviations from either theoretical framework.

  16. Computation of NLO Processes Involving Heavy Quarks Using Loop-Tree Duality

    CERN Document Server

    Driencourt-Mangin, Felix

    2016-01-01

    We present a new method to compute higher-order corrections to physical cross-sections, at Next-to-Leading Order and beyond. This method, based on the Loop Tree Duality, leads to locally integrable expressions in four dimensions. By introducing a physically motivated momentum mapping between the momenta involved in the real and the virtual contributions, infrared singularities naturally cancel at integrand level, without the need to introduce subtraction counter-terms. Ultraviolet singularities are dealt with by using dual representations of suitable counter-terms, with some subtleties regarding the self-energy contributions. As an example, we apply this method to compute the $1\\to2$ decay rate in the context of a scalar toy model with massive particles.

  17. Exact duality and Bjorken sum rule in heavy quark models à la Bakamjian-Thomas

    CERN Document Server

    Le Yaouanc, A; Pène, O; Raynal, J C

    1996-01-01

    The heavy mass limit of quark models based on the Bakamjian-Thomas cons\\-truction reveals remarkable features. In addition to previously demonstrated properties of covariance and Isgur-Wise scaling, exact duality, leading to the Bjorken-Isgur-Wise sum rule, is proven, for the first time to our knowledge in relativistic quark models. Inelastic as well as elastic contributions to the sum rule are then discussed in terms of ground state averages of a few number of operators corresponding to the nonrelativistic dipole operator and various relativistic corrections.

  18. Modelling of top quark pairs production in association with Standard Model bosons or heavy quark pairs.

    CERN Document Server

    Moreno Llacer, Maria; The ATLAS collaboration

    2016-01-01

    Production of top quark pairs in association with heavy Standard Model bosons or with heavy flavour quark-pairs is important both as a signal and a background in several ATLAS analyses. Strong constraints on such processes cannot at present be obtained from data, and therefore their modeling by Monte Carlo simulation as well as the associated uncertainties are important. This poster documents the Monte Carlo samples currently being used in ATLAS for the ttH and ttV (V=W,Z vector bosons) and tt+bottom and charm quark pairs processes for sqrt(s)=13 TeV proton-proton collisions.

  19. Associated production of prompt photons and heavy quarks in off-shell gluon-gluon fusion

    Energy Technology Data Exchange (ETDEWEB)

    Baranov, S.P. [P.N. Lebedev Physics Institute, Moscow (Russian Federation); Lipatov, A.V.; Zotov, N.P. [M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation)

    2008-08-15

    In the framework of the k{sub T}-factorization approach, we study the production of prompt photons associated with heavy (charm and beauty) quarks in hadron-hadron collisions at high energies. Our consideration is based on the amplitude for the production of a single photon associated with a quark pair in the fusion of two off-shell gluons. The total and differential cross sections are presented and the conservative error analysis is performed. Two sets of unintegrated gluon distributions in the proton have been used in numerical calculation: the one obtained from Ciafaloni-Catani-Fiorani-Marchesini evolution equation and the other from Kimber-Martin-Ryskin prescription. The theoretical results are compared with recent experimental data taken by the CDF collaboration at the Fermilab Tevatron. Our analysis extends to specific angular correlations between the produced prompt photons and muons originating from semileptonic decays of the final charmed or beauty quarks. We point out the importance of such observables, which can serve as a crucial test for the unintegrated gluon densities in a proton. Finally, we extrapolate the theoretical predictions to the CERN LHC energies. (orig.)

  20. Associated photon and heavy quark production at high energy within k_T-factorization

    CERN Document Server

    Zotov, N P; Malyshev, M A

    2013-01-01

    In the framework of the k_T-factorization approach, the production of prompt photons in association with a heavy (charm or beauty) quarks at high energies is studied. The consideration is based on the O(\\alpha \\alpha_s^2) off-shell amplitudes of gluon-gluon fusion and quark-(anti)quark interaction subprocesses. The unintegrated parton densities in a proton are determined using the Kimber-Martin-Ryskin prescription. Our numerical predictions are compared with the D0 and CDF experimental data. Also we extend our results to LHC energies.

  1. Study of the linked dipole chain model in heavy quark production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Lipatov, Artem V. [Physical Department, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)]. E-mail: lipatov@theory.sinp.msu.ru; Leif Loennblad [Dept. of Theoretical Physics, Lund (Sweden)]. E-mail: Leif.Lonnblad@thep.lu.se; Zotov, Nikolai P. [D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)]. E-mail: zotov@theory.sinp.msu.ru

    2004-01-01

    We present calculations of charm and beauty production at Tevatron within the framework of k{sub T} -factorization, using the unintegrated gluon distributions as obtained from the Linked Dipole Chain model. The analysis covers transverse momentum and rapidity distributions and the azimuthal correlations between b and b-bar quarks (or rather muons from their decay) which are powerful tests for the different unintegrated gluon distributions. We compare the theoretical results with recent experimental data taken by D{phi} and CDF collaborations at the Tevatron Run I and II. (author)

  2. Parity Violation in Decays of Z Bosons into Heavy Quarks at SLD

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Thomas R

    2002-09-16

    This work presents measurements of the parity-violation parameters A{sub c} and A{sub b} made at the Z pole. These measurements include the data taken with the SLD detector at the SLAC Linear Collider (SLC) during the period 1996-98. Heavy flavor events are selected with high efficiency and purity by searching for displaced vertices, identified with the SLD precision CCD vertex detector. Two methods are used for quark/antiquark discrimination: the net charge of the displaced vertex, and tracks in the displaced vertex identified as kaons by the SLD Cherenkov Ring Imaging Detector (CRID). The signal purities and analyzing powers are calibrated from the data to reduce the systematic errors and avoid experimental bias. The results are A{sub c} = 0.673 {+-} 0.029 {+-} 0.023 and A{sub b} = 0.919 {+-} 0.018 {+-} 0.017, where the first error is statistical and the second systematic. Fits to the electroweak data performed by the LEP Electroweak Working Group are used to study the consistency of the Standard Model, and to constrain the mass of the Standard Model Higgs boson.

  3. Heavy quark spin selection rule and the properties of the X(3872)

    Energy Technology Data Exchange (ETDEWEB)

    Voloshin, M.B. [William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN 55455 (United States) and Institute of Theoretical and Experimental Physics, Moscow 117259 (Russian Federation)]. E-mail: voloshin@umn.edu

    2004-12-16

    The properties of the resonance X(3872) are discussed under the assumption that this resonance is dominantly a 'molecular'J{sup PC}=1{sup ++} state of neutral D and D* mesons. It is argued that these properties should be dominated by the states with the total spin of the charmed quark-antiquark pair equal to one. As a practical application of this observation the ratio of the rates of the decays X->{pi}{sup 0}{chi}{sub cJ} for different J is predicted. It is also pointed out that the total rate of these decays is likely to be comparable to that of the observed transitions X->{pi}{sup +}{pi}{sup -}J{psi} and X->{pi}{sup +}{pi}{sup -}{pi}{sup 0}J{psi}. The decays of the X into light hadrons and its production in hadronic processes are also briefly discussed.

  4. Non-perturbative Heavy Quark Effective Theory: An application to semi-leptonic B-decays

    CERN Document Server

    Della Morte, Michele; Simma, Hubert; Sommer, Rainer

    2015-01-01

    We review a lattice strategy how to non-perturbatively determine the coefficients in the HQET expansion of all components of the heavy-light axial and vector currents, including 1/m_h-corrections. We also discuss recent preliminary results on the form factors parameterizing semi-leptonic B-decays at the leading order in 1/m_h.

  5. Effective theory for heavy quark QCD at finite temperature and density with stochastic quantization

    Energy Technology Data Exchange (ETDEWEB)

    Neuman, Mathias

    2015-07-01

    In this thesis we presented the derivation as well as the numerical and analytical treatment of an effective theory for lattice Quantum Chromodynamics (LQCD). We derived the effective theory directly from LQCD, which allows us to systematically introduce further improvements. The derivation was performed by means of an expansion around the limit of infinite quark masses and infinite gauge coupling. Using this theory we were able to derive results in the region of large densities. This region is, due to the sign problem, inaccessible to standard LQCD approaches. Although LQCD simulations at large densities have been performed recently by applying stochastic quantization, those are still limited to lattice with low numbers of timeslices and therefor can not reach the low temperature region. Furthermore, they can not be crosschecked with Monte-Carlo simulations. Since the equivalence between stochastic quantization and Monte-Carlo is unproven for the case of finite density systems, new approaches to access the cold dense region of the QCD phase diagram are desirable. The effective theory presented in this thesis provides such an approach. We introduced continuum QCD in chapter 2. In chapter 3 we presented how LQCD, i.e. QCD in a discretized space-time, can be formulated and used as a tool to explore the non-perturbative regions of the QCD phase diagram. Special emphasis was placed on simulations at finite baryon densities and the numerical problems that arise in this region. These problems are caused by the complexification of the action and are known as the sign problem. We gave a detailed presentation of the derivation of our effective theory in chapter 4. For this we performed expansions around the limit of strong coupling and static quarks, κ=β=0, introducing corrections order by order in the expansion parameters κ and β. Truncating the theory at different orders allowed us to determine the parameter region where the convergence to full LQCD is good. The gauge corrections are sufficient to reach β∼6, which translates to lattice spacings down to a ∼0.1 fm. Furthermore we determined the convergence in κ by simulating the action truncated at different orders. Due to the three dimensional nature of our theory the convergence depends on the temporal extent N{sub τ}. We concluded that our theory converges well up to values of at least (N{sub τ}κ{sup 2})/(3) ∼ 0.04. Both results can be improved by deriving further corrections. In chapter 5 we presented the numerical treatment of our theory. While the sign problem is still present, it is mild compared to the case of full LQCD. This allowed us to use both Monte-Carlo with reweighting and stochastic quantization in order to crosscheck results. This confirms the validity of stochastic quantization for our theory, which is our method of choice since, in contrast to reweighting, it is not limited to small lattice volumes. We presented results for two parameter regions, the region of large density and low temperatures, and the region of high temperature and low density. For the cold dense region we calculated several thermodynamical quantities and performed continuum extrapolations. This allows us to make a connection to continuum QCD, although in a parameter region far away from the physical point. The results show the onset from the vacuum to the region of finite density, displaying Silver Blaze behavior. We furthermore demonstrated the existence of a finite binding energy between baryonic states, which in the continuum are responsible for the formation of nuclear matter. Although experiments show the transition from the vacuum to the region of finite density to be of first order for low enough temperatures, the convergence region of our theory is not large enough to reproduce this. Nevertheless, we where able to find signals for a change from a crossover to a true phase transition when we left this region. This demonstrates that our theory is in principle able to reproduce the qualitative features of cold and dense nuclear matter. In the region of high temperatures

  6. QCD string in excited heavy-light mesons and heavy-quark hybrids

    CERN Document Server

    Kalashnikova, Yu S

    2016-01-01

    The QCD string model is employed to evaluate the masses of orbitally and radially excited heavy-light mesons and lightest hybrids in the spectrum of charmonium and bottomonium. The number of parameters of the model is reduced to only seven which are the string tension, the two values of the strong coupling constant (one for heavy-light and $\\bar{c}c$ mesons and one for $\\bar{b}b$ mesons), and the four overall spectrum shift constants which depend on the quark contents of the particular meson or hybrid family. A few well-established states in the spectrum of heavy-light and heavy-heavy mesons are used to fix these parameters, and then the masses of other mesons and hybrids come out as predictions of the model which are confronted with the existing experimental data, and a few suggestions are made concerning yet not measured quantum numbers of some states in the spectrum of charmonium and bottomonium.

  7. HATHOR. HAdronic Top and Heavy quarks crOss section calculatoR

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, M.; Lacker, H.; Langenfeld, U.; Uwer, P.; Wiedermann, M. [Berlin Univ. (Germany). Inst. fuer Physik; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2010-07-15

    We present a program to calculate the total cross section for top-quark pair production in hadronic collisions. The program takes into account recent theoretical developments such as approximate next-to-next-to-leading order perturbative QCD corrections and it allows for studies of the theoretical uncertainty by separate variations of the factorization and renormalization scales. In addition it offers the possibility to obtain the cross section as a function of the running top-quark mass. The program can also be applied to a hypothetical fourth quark family provided the QCD couplings are standard. (orig.)

  8. Two-loop anomalous dimensions of heavy baryon currents in heavy quark effective theory

    CERN Document Server

    Groote, S; Yakovlev, O I

    1996-01-01

    We present results on the two-loop anomalous dimensions of the heavy baryon HQET currents J=(q^TC\\Gamma\\tau q)\\Gamma'Q with arbitrary Dirac matrices \\Gamma and \\Gamma'. From our general result we obtain the two-loop anomalous dimensions for currents with quantum numbers of the ground state heavy baryons \\Lambda_Q, \\Sigma_Q and \\Sigma_Q^*. As a by-product of our calculation and as an additional check we rederive the known two-loop anomalous dimensions of mesonic scalar, pseudoscalar, vector, axial vector and tensor currents (J=\\bar q\\Gamma q) in massless QCD as well as in HQET.

  9. Third-order QCD corrections to heavy quark pair production near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Schuller, Kurt

    2008-11-07

    The measurement of the top quark mass is an important task at the future International Linear Collider. The most promising process is the top quark pair production in the threshold region. In this region the top quarks behave non-relativistically and a perturbative treatment using effective field theories is possible. Current second order theoretical predictions in a fixed order approach show an uncertainty which is bigger than the expected experimental errors. Therefore, an improvement of the cross section calculation is desirable. There are two ways to incorporate higher order effects, one is to calculate the full next order in the fixed order approach, another possibility is to resum large logarithms. In this work, the fixed order calculation has been extended to the third order in perturbation theory for the QCD corrections. The result is a strongly improved scale behavior and a better understanding of heavy quarkonium systems. The Green function result is given in a semi-analytic form. The energy levels and wave functions for heavy quarkonium states have been calculated from the poles of the Green function and are presented for arbitrary quantum number n. The results have been implemented in a Mathematica program which makes the data easily accessible. Once some missing matching coefficients are calculated, and a complete electroweak calculation is available, the results of this work can be used to improve the precision of the top quark mass measurement to an uncertainty of less than 50 MeV. An inclusion of initial state radiation and beam effects are essential for a realistic observable. In the future, the results obtained could be used for a third order resummation of large logarithms. Further applications are also the extraction of the bottom quark mass with sum rules. (orig.)

  10. Heavy Quark Symmetries: Molecular partners of the X(3872 and Zb(10610/Zb′(10650

    Directory of Open Access Journals (Sweden)

    Guo Feng-Kun

    2014-06-01

    Full Text Available In this work, we have made use of the identification of the X(3872 and Zb(10610/Zb′(10650 as heavy meson-heavy antimeson molecules to establish some consequences derived from the symmetries that these heavy meson-heavy antimeson systems must have. We show the most general effective lagrangian that respects these symmetries only depends on four undetermined low energy constants (LECs, which will be fitted to reproduce the experimental data about the resonances we are identifying as molecular states. Then, we obtain a whole new set of states in the spectrum that could also be thought as heavy meson-heavy antimeson molecules. Finally, using another different symmetry: Heavy Antiquark-Diquark Symmetry, we can also establish a set of pentaquark-like states taking advantage of the previous LEC calculation.

  11. Searches for new phenomena with heavy quarks and multileptons at the LHC

    CERN Document Server

    Valery, Loic; The ATLAS collaboration

    2015-01-01

    This talk presents searches for heavy vector-like quarks as well as top-related searches for new physics. Two recent searches, performed in the one-lepton channel are presented, and a particular emphasize is put on the searches in the context of multi-lepton final states.

  12. Heavy quark effective theory computation of the mass of the bottom quark

    Energy Technology Data Exchange (ETDEWEB)

    Della Morte, M. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Garron, N.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Papinutto, M. [INFN Sezione di Roma Tre, Rome (Italy)

    2006-10-15

    We present a fully non-perturbative computation of the mass of the b-quark in the quenched approximation. Our strategy starts from the matching of HQET to QCD in a finite volume and finally relates the quark mass to the spin averaged mass of the B{sub s} meson in HQET. All steps include the terms of order {lambda}{sup 2}/m{sub b}. We discuss the computation and renormalization of correlation functions at order 1/m{sub b}. With the strange quark mass fixed from the Kaon mass and the QCD scale set through r{sub 0}=0.5 fm, we obtain a renormalization group invariant mass M{sub b}=6.758(86) GeV or anti m{sub b}(anti m{sub b})=4.347(48) GeV in the MS scheme. The uncertainty in the computed {lambda}{sup 2}/m{sub b} terms contributes little to the total error and {lambda}{sup 3}/m{sup 2}{sub b} terms are negligible. The strategy is promising for full QCD as well as for other B-physics observables. (orig.)

  13. Effective theory for heavy quark QCD at finite temperature and density with stochastic quantization

    Energy Technology Data Exchange (ETDEWEB)

    Neuman, Mathias

    2015-07-01

    In this thesis we presented the derivation as well as the numerical and analytical treatment of an effective theory for lattice Quantum Chromodynamics (LQCD). We derived the effective theory directly from LQCD, which allows us to systematically introduce further improvements. The derivation was performed by means of an expansion around the limit of infinite quark masses and infinite gauge coupling. Using this theory we were able to derive results in the region of large densities. This region is, due to the sign problem, inaccessible to standard LQCD approaches. Although LQCD simulations at large densities have been performed recently by applying stochastic quantization, those are still limited to lattice with low numbers of timeslices and therefor can not reach the low temperature region. Furthermore, they can not be crosschecked with Monte-Carlo simulations. Since the equivalence between stochastic quantization and Monte-Carlo is unproven for the case of finite density systems, new approaches to access the cold dense region of the QCD phase diagram are desirable. The effective theory presented in this thesis provides such an approach. We introduced continuum QCD in chapter 2. In chapter 3 we presented how LQCD, i.e. QCD in a discretized space-time, can be formulated and used as a tool to explore the non-perturbative regions of the QCD phase diagram. Special emphasis was placed on simulations at finite baryon densities and the numerical problems that arise in this region. These problems are caused by the complexification of the action and are known as the sign problem. We gave a detailed presentation of the derivation of our effective theory in chapter 4. For this we performed expansions around the limit of strong coupling and static quarks, κ=β=0, introducing corrections order by order in the expansion parameters κ and β. Truncating the theory at different orders allowed us to determine the parameter region where the convergence to full LQCD is good. The gauge corrections are sufficient to reach β∼6, which translates to lattice spacings down to a ∼0.1 fm. Furthermore we determined the convergence in κ by simulating the action truncated at different orders. Due to the three dimensional nature of our theory the convergence depends on the temporal extent N{sub τ}. We concluded that our theory converges well up to values of at least (N{sub τ}κ{sup 2})/(3) ∼ 0.04. Both results can be improved by deriving further corrections. In chapter 5 we presented the numerical treatment of our theory. While the sign problem is still present, it is mild compared to the case of full LQCD. This allowed us to use both Monte-Carlo with reweighting and stochastic quantization in order to crosscheck results. This confirms the validity of stochastic quantization for our theory, which is our method of choice since, in contrast to reweighting, it is not limited to small lattice volumes. We presented results for two parameter regions, the region of large density and low temperatures, and the region of high temperature and low density. For the cold dense region we calculated several thermodynamical quantities and performed continuum extrapolations. This allows us to make a connection to continuum QCD, although in a parameter region far away from the physical point. The results show the onset from the vacuum to the region of finite density, displaying Silver Blaze behavior. We furthermore demonstrated the existence of a finite binding energy between baryonic states, which in the continuum are responsible for the formation of nuclear matter. Although experiments show the transition from the vacuum to the region of finite density to be of first order for low enough temperatures, the convergence region of our theory is not large enough to reproduce this. Nevertheless, we where able to find signals for a change from a crossover to a true phase transition when we left this region. This demonstrates that our theory is in principle able to reproduce the qualitative features of cold and dense nuclear matter. In the region of high temperatures and low densities, we investigated the chiral condensate and the nature of the critical endpoint of the Roberge-Weiss transition. In both cases LQCD calculations exist for comparison. While the behaviour of the chiral condensate can be modeled quantitatively, the second tricritical Roberge-Weiss endpoint located in [19] is absent in our theory. We discussed possible reasons for this, but can not offer a final conclusion so far. Chapter 6 demonstrated how, in the cold dense region, our effective theory can be solved analytically. We used this to accurately reproduce the numerical results from chapter 5. We furthermore derived analytic expressions for different thermodynamical observables, demonstrating how to leading order the binding energy can be described by a Yukawa potential. We finally showed how the analytic results can be resummed, potentially extending their range of validity beyond the range of the original effective theory. Future research perspectives lie in the possibility to systematically improve the theory. Using the methods described in chapter 4, higher orders can be derived in order to extend the convergence region. This is much simplified in the limit of low temperature and high density presented in chapter 4, which simultaneously is the most interesting parameter region due to the lack of LQCD simulations. Together with the resummation scheme from chapter 6 it should be possible to extend the theory far beyond the parameter range presented here. This will allow for better continuum extrapolations and the use of lighter quarks. Simultaneously the use of lighter quarks will mean that it is no longer possible to use the pure gauge beta function in order to set the scale, so those will have to come from LQCD simulations including fermions.

  14. Towards a non-perturbative matching of HQET and QCD with dynamical light quarks

    CERN Document Server

    Della Morte, Michele; Heitger, Jochen; Meyer, Harvey B.; Simma, Hubert; Sommer, Rainer

    2007-01-01

    We explain how the strategy of solving renormalization problems in HQET non-perturbatively by a matching to QCD in finite volume can be implemented to include dynamical fermions. As a primary application, some elements of an HQET computation of the mass of the b-quark beyond the leading order with N_f=2 are outlined. In particular, the matching of HQET and QCD requires relativistic QCD simulations in a volume with L ~ 0.5 fm, which will serve to quantitatively determine the heavy quark mass dependence of heavy-light meson observables in the continuum limit of finite-volume two-flavour lattice QCD. As a preparation for the latter, we report on our determination of the renormalization constants and improvement coefficients relating the renormalized current and subtracted bare quark mass in the relevant weak coupling region. The calculation of these coefficients employs a constant physics condition in the Schroedinger functional scheme, where the box size L is fixed by working at a prescribed value of the renorm...

  15. Asymmetric recombination and electron spin relaxation in the semiclassical theory of radical pair reactions

    CERN Document Server

    Lewis, Alan M; Hore, P J

    2014-01-01

    We describe how the semiclassical theory of radical pair recombination reactions recently introduced by two of us [D. E. Manolopoulos and P. J. Hore, J. Chem. Phys. 139, 124106 (2013)] can be generalised to allow for different singlet and triplet recombination rates. This is a non-trivial generalisation because when the recombination rates are different the recombination process is dynamically coupled to the coherent electron spin dynamics of the radical pair. Furthermore, because the recombination operator is a two-electron operator, it is no longer sufficient simply to consider the two electrons as classical vectors: one has to consider the complete set of 16 two-electron spin operators as independent classical variables. The resulting semiclassical theory is first validated by comparison with exact quantum mechanical results for a model radical pair containing 12 nuclear spins. It is then used to shed light on the spin dynamics of a carotenoid-porphyrin-fullerene (CPF) triad containing considerably more nu...

  16. RECOMBINANT HORSERADISH PEROXIDASE FOR ANALYTICAL APPLICATIONS

    OpenAIRE

    2013-01-01

    The article deals with prospects of using recombinant horseradish peroxidase in analytical biochemistry and biotechnology. Problems of recombinant horseradish peroxidase cloning in different expression systems, possible approaches to their solution, advantages of recombinant recombinant horseradish peroxidase and recombinant horseradish peroxidase-fusion proteins for immunoassays are considered. Possibility for development of mediatorless bienzyme biosensor for peroxide and metabolites, yield...

  17. Analysis of interchromosomal mitotic recombination.

    Science.gov (United States)

    McGill, C B; Shafer, B K; Higgins, D R; Strathern, J N

    1990-07-01

    A novel synthetic locus is described that provides a simple assay system for characterizing mitotic recombinants. The locus consists of the TRP1 and HIS3 genes inserted into chromosome III of S. cerevisiae between the CRY1 and MAT loci. Defined trp1 and his3 alleles have been generated that allow the selection of interchromosomal recombinants in this interval. Trp+ or His+ recombinants can be divided into several classes based on coupling of the other alleles in the interval. The tight linkage of the CRY1 and MAT loci, combined with the drug resistance and cell type phenotypes that they respectively control, facilitates the classification of the recombinants without resorting to tetrad dissection. We present the distribution of spontaneous recombinants among the classes defined by this analysis. The data suggest that the recombination intermediate can have regions of symmetric strand exchange and that co-conversion tracts can extend over 1-3 kb. Continuous conversion tracts are favored over discontinuous tracts. The distribution among the classes defined by this analysis is altered in recombinants induced by UV irradiation.

  18. Recombinant human DNase in children with airway malacia and lower respiratory tract infection.

    NARCIS (Netherlands)

    Boogaard, R.; Jongste, J.C. de; Vaessen-Verberne, A.A.; Hop, W.C.J.; Merkus, P.J.F.M.

    2009-01-01

    BACKGROUND: Children with airway malacia often have protracted courses of airway infections, because dynamic airway collapse during coughing results in impaired mucociliary clearance. The aim of this study was to determine the effect of the mucolytic drug recombinant human deoxyribonuclease

  19. Testing for recombinant erythropoietin.

    Science.gov (United States)

    Delanghe, Joris R; Bollen, Mathieu; Beullens, Monique

    2008-03-01

    Erythropoietin (Epo) is a glycoprotein hormone that promotes the production of red blood cells. Recombinant human Epo (rhEpo) is illicitly used to improve performance in endurance sports. Doping in sports is discouraged by the screening of athletes for rhEpo. Both direct tests (indicating the presence of exogeneous Epo isoforms) and indirect tests (indicating hematological changes induced by exogenous Epo administration) can be used for Epo detection. At present, the test adopted by the World Anti Doping Agency is based on a combination of isoelectric focusing and double immunoblotting, and distinguishes between endogenous and rhEpo. However, the adopted monoclonal anti-Epo antibodies are not monospecific. Therefore, the test can occasionally lead to the false-positive detection of rhEpo (epoetin-beta) in post-exercise, protein-rich urine, or in case of contamination of the sample with microorganisms. An improved preanalytical care may counteract a lot of these problems. Adaptation of the criteria may be helpful to further refine direct Epo testing. Indirect tests have the disadvantage that they require blood instead of urine samples, but they can be applied to detect a broader range of performance improving techniques which are illicitly used in sports.

  20. Controlled release from recombinant polymers.

    Science.gov (United States)

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-09-28

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed.