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

International Nuclear Information System (INIS)

Sommer, R.

2006-11-01

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. (orig.)

Heavy Quark Dynamics toward thermalization: RAA, υ1, υ2, υ3

Directory of Open Access Journals (Sweden)

Plumari Salvatore

2018-01-01

Full Text Available We describe the propagation of Heavy quarks (HQs in the quark-gluon plasma (QGP within a relativistic Boltzmann transport (RBT approach. The interaction between heavy quarks and light quarks is described within quasi-particle approach which is able to catch the main features of non-perturbative interaction as the increasing of the interaction in the region of low temperature near TC. In our calculations the hadronization of charm quarks in D mesons is described by mean of an hybrid model of coalescence plus fragmentation. We show that the coalescence play a key role to get a good description of the experimental data for the nuclear suppression factor RAA and the elliptic flow υ2(pT at both RHIC and LHC energies. Moreover, we show some recent results on the direct flow υ1 and triangular flow υ3 of D meson.

Elastic and radiative heavy quark interactions in ultra-relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Uphoff, Jan; Fochler, Oliver; Xu, Zhe; Greiner, Carsten

2015-01-01

Elastic and radiative heavy quark interactions with light partons are studied with the partonic transport model named the Boltzmann approach to multiparton scatterings (BAMPSs). After calculating the cross section of radiative processes for finite masses in the improved Gunion–Bertsch approximation and verifying this calculation by comparing to the exact result, we study elastic and radiative heavy quark energy loss in a static medium of quarks and gluons. Furthermore, the full 3 + 1D space–time evolution of gluons, light quarks, and heavy quarks in ultra-relativistic heavy-ion collisions at the BNL Relativistic Heavy-Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC) are calculated with BAMPS including elastic and radiative heavy flavor interactions. Treating light and heavy particles on the same footing in the same framework, we find that the experimentally measured nuclear modification factor of charged hadrons and D mesons at the LHC can be simultaneously described. In addition, we calculate the heavy flavor evolution with an improved screening procedure from hard-thermal-loop calculations and confront the results with experimental data of the nuclear modification factor and the elliptic flow of heavy flavor particles at the RHIC and the LHC. (paper)

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.

Non-perturbative quark mass renormalization

CERN Document Server

Capitani, S.; Luescher, M.; Sint, S.; Sommer, R.; Weisz, P.; Wittig, H.

1998-01-01

We show that the renormalization factor relating the renormalization group invariant quark masses to the bare quark masses computed in lattice QCD can be determined non-perturbatively. The calculation is based on an extension of a finite-size technique previously employed to compute the running coupling in quenched QCD. As a by-product we obtain the $\\Lambda$--parameter in this theory with completely controlled errors.

Thoughts on non-perturbative thermalization and jet quenching in heavy ion collisions

International Nuclear Information System (INIS)

Kovchegov, Yuri V.

2006-01-01

We start by presenting physical arguments for the impossibility of perturbative thermalization leading to (non-viscous) Bjorken hydrodynamic description of heavy ion collisions. These arguments are complimentary to our more formal argument presented in [Yu.V. Kovchegov, hep-ph/0503038]. We argue that the success of hydrodynamic models in describing the quark-gluon system produced in heavy ion collisions could only be due to non-perturbative strong coupling effects. We continue by studying non-perturbative effects in heavy ion collisions at high energies. We model non-perturbative phenomena by an instanton ensemble. We show that non-perturbative instanton vacuum fields may significantly contribute to jet quenching in nuclear collisions. At the same time, the instanton ensemble contribution to thermalization is likely to be rather weak, leading to non-perturbative thermalization time comparable to the time of hadronization. This example illustrates that jet quenching is not necessarily a signal of a thermalized medium. Indeed, since the instanton models do not capture all the effects of QCD vacuum (e.g., they do not account for confinement), there may be other non-perturbative effects facilitating thermalization of the system

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.

QCD in heavy quark production and decay

International Nuclear Information System (INIS)

Wiss, J.

1997-01-01

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

Heavy-quark physics in quantum chromodynamics

International Nuclear Information System (INIS)

Brodsky, S.J.

1991-04-01

Heavy quarks can expose new symmetries and novel phenomena in QCD not apparent in ordinary hadronic systems. In these lectures I discuss the use of effective-Lagrangian and light-cone Fock methods to analyze exclusive heavy hadron decays such as Υ → p bar p and B → ππ, and also to derive effective Schroedinger and Dirac equations for heavy quark systems. Two contributions to the heavy quark structure functions of the proton and other light hadrons are identified: an ''extrinsic'' contribution associated with leading twist QCD evolution of the gluon distribution, and a higher twist ''intrinsic'' contribution due to the hardness of high-mass fluctuations of multi-gluon correlations in hadronic wavefunctions. A non-perturbative calculation of the heavy quark distribution of a meson in QCD in one space and one time is presented. The intrinsic higher twist contributions to the pion and proton structure functions can dominate the hadronic production of heavy quark systems at large longitudinal momentum fraction x F and give anomalous contributions to the quark structure functions of ordinary hadrons at large x bj . I also discuss a number of ways in which heavy quark production in nuclear targets can test fundamental QCD phenomena and provide constraints on hadronic wavefunctions. The topics include color transparency, finite formation time, and predictions for charm production at threshold, including nuclear-bound quarkonium. I also discuss a number of QCD mechanisms for the suppression of J/ψ and Υ production in nuclear collisions, including gluon shadowing, the peripheral excitation of intrinsic heavy quark components at large x F , and the coalescence of heavy quarks with co-moving spectators at low x F

Topics in the theory of heavy-quark systems

International Nuclear Information System (INIS)

Flory, C.A.

1981-04-01

Due to the kinematic and dynamic simplifications possible because of the large mass of heavy quark bound states, certain properties of these systems can be quantitatively analyzed within the framework of quantum chromodynamics. It is clear that dimensionally the size of the bound state is proportional to the inverse quark mass, and for very heavy quarkonia the radius of the system should become smaller than that of normal hadrons. When this small system interacts with external long wavelength field quanta, the natural expansion that results is of a multipole type, analogous to the familiar multipole expansion in electrodynamics. This multipole expansion has better convergence properties than the standard perturbative treatment in certain kinematic regimes, which opens up a new area for strong interaction physics calculations. More specifically, it is ideally suited to investigate soft non-perturbative effects in QCD which appear to be so crucial to present day phenomenology and the conjectured confinement mechanism

QCD improved exclusive rare B-decays at the heavy b-quark limit

International Nuclear Information System (INIS)

Liu Dongsheng.

1993-09-01

The renormalization effects from the b-quark scale down to the non-perturbative QCD regime are studied for rare B-decays at the heavy b-quark limit. Phenomenological consequences of these effects are investigated. We find that the anomalous scaling behaviour plays a positive role in making non-perturbative model calculations consistent with recent CLEO measurements of B → K*γ. (author). 21 refs, 3 tabs

Heavy hybrid stars from multi-quark interactions

International Nuclear Information System (INIS)

Benic, Sanjin

2014-01-01

We explore the possibility of obtaining heavy hybrid stars within the framework of the two flavor Nambu-Jona-Lasinio model that includes 8-quark interactions in the scalar and in the vector channel. The main impact of the 8-quark scalar channel is to reduce the onset of quark matter, while the 8-quark vector channel acts to stiffen the equation of state at high densities. Within the parameter space where the 4-quark vector channel is small, and the 8-quark vector channel sizeable, stable stars with masses of 2 M ⊙ and above are found to hold quark matter in their cores. (orig.)

Renormalons and the heavy quark effective theory

CERN Document Server

Martinelli, G; Martinelli, G; Sachrajda, C T

1995-01-01

We propose a non-perturbative method for defining the higher dimensional operators which appear in the Heavy Quark Effective Theory (HQET), such that their matrix elements are free of renormalon singularities, and diverge at most logarithmically with the ultra-violet cut-off. Matrix elements of these operators can be computed numerically in lattice simulations of the HQET. We illustrate our procedures by presenting physical definitions of the binding energy (\\lb) and of the kinetic energy (-\\lambda_1/2m_Q) of the heavy quark in a hadron. This allows us to define a ``subtracted pole mass", whose inverse can be used as the expansion parameter in applications of the HQET.

A nonperturbative treatment of spin-dependent interactions of light and heavy quarkonia

International Nuclear Information System (INIS)

Schoeberl, F.

1986-01-01

We propose a nonrelativistic potential model with a regularized Coulomb potential at short range which leads to spin-dependent interactions which are at most as singular as 1/r. The Schroedinger equation is solved numerically including all spin-dependent interactions nonperturbatively. The predicted spectrum of light and heavy quarkonia is in remarkable agreement with experiment. Even the leptonic decay widths as well as the M1 transitions are in agreement with experiment. (Author)

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 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_π ≈ 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(α_sa). 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 f_B⁰ = 196.2(15.7) MeV, f_B⁺ = 195.4(15.8) MeV, f_Bs = 235.4(12.2) MeV, f_Bs/f_B⁰ = 1.193(59), and f_Bs/f_B⁺ = 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.

Heavy quark production in semihard interactions of nucleons

International Nuclear Information System (INIS)

Levin, E.M.; Ryskin, M.G.; Shabel'skij, Yu.M.; Shuvaev, A.G.

1991-01-01

Cross section of semihard process (heavy quark production) in the interactions of high-energy nucleons is calculated. The normalization of gluon structure function at small x and the role of absorption corrections are discussed in detail. The virtuality of interacting gluons as well as their transverse motion and possible various polarizations are accounted for in calculations. Comparatively large cross section of the high-energy inclusive b-quark production (σ(b-barb) is predicted, in particular, σ(p-barp→b-barb)=150-300 μb at √s=1.8 TeV

Controlling quark mass determinations non-perturbatively in three-flavour QCD

CERN Document Server

Campos, Isabel

2017-01-01

The determination of quark masses from lattice QCD simulations requires a non-perturbative renormalization procedure and subsequent scale evolution to high energies, where a conversion to the commonly used MS-bar scheme can be safely established. We present our results for the non-perturbative running of renormalized quark masses in Nf=3 QCD between the electroweak and a hadronic energy scale, where lattice simulations are at our disposal. Recent theoretical advances in combination with well-established techniques allows to follow the scale evolution to very high statistical accuracy, and full control of systematic effects.

Towards a non-perturbative matching of HQET and QCD with dynamical light quarks

International Nuclear Information System (INIS)

Della Morte, M.; Simma, H.; Sommer, R.

2007-10-01

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 Schrodinger functional scheme, where the box size L is fixed by working at a prescribed value of the renormalized coupling. (orig.)

Towards a non-perturbative matching of HQET and QCD with dynamical light quarks

Energy Technology Data Exchange (ETDEWEB)

Della Morte, M. [CERN, Geneva (Switzerland). Physics Dept.; Fritzsch, P.; Heitger, J. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Meyer, H.B. [Massachusets Institute of Technology, Center for Theoretical Physics, Cambridge, MA (United States); Simma, H.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2007-10-15

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{sub f} =2 are outlined. In particular, the matching of HQET and QCD requires relativistic QCD simulations in a volume with L{approx}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 Schrodinger functional scheme, where the box size L is fixed by working at a prescribed value of the renormalized coupling. (orig.)

Recent Developments in Heavy Quark and Quarkonium Production

International Nuclear Information System (INIS)

Thomas Mehen

2004-01-01

Recent measurements of J/ψ production in e + e - colliders pose a challenge to the NRQCD factorization theorem for quarkonium production. Discrepancies between leading order calculations of color-octet contributions and the momentum distribution of J/ψ observed by Belle and BaBar are resolved by resumming large perturbative and nonperturbative corrections that are enhanced near the kinematic endpoint. The large cross sections for J/ψ + c + (bar c) and double quarkonium production remain poorly understood. Nonperturbative effects in fixed-target hadroproduction of open charm are also discussed. Large asymmetries in the production of charm mesons and baryons probe nonperturbative corrections to the QCD factorization theorem. A power correction called heavy-quark recombination can economically explain these asymmetries with a few universal parameters

Non-perturbative heavy quark effective theory. An application to semi-leptonic B-decays

International Nuclear Information System (INIS)

Della Morte, Michele; Heitger, Jochen; Simma, Hubert; Sommer, Rainer; Humboldt-Universitaet, Berlin

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 .

Exploring the Invisible Renormalon Renormalization of the Heavy-Quark Kinetic Energy

CERN Document Server

Neubert, M

1997-01-01

Using the virial theorem of the heavy-quark effective theory, we show that the mixing of the operator for the heavy-quark kinetic energy with the identity operator is forbidden at the one-loop order by Lorentz invariance. This explains why such a mixing was not observed in several one-loop calculations using regularization schemes with a Lorentz-invariant UV regulator, and why no UV renormalon singularity was found in the matrix elements of the kinetic operator in the bubble approximation (the ``invisible renormalon''). On the other hand, we show that the mixing is not protected in general by any symmetry, and it indeed occurs at the two-loop order. This implies that the parameter $\\lambda_1^H$ of the heavy-quark effective theory is not directly a physical quantity, but requires a non-perturbative subtraction.

Investigation of heavy quark and multiple interactions at HERA

International Nuclear Information System (INIS)

Magro, L.M.

2005-09-01

This thesis is oriented to the study of heavy quark photoproduction and multiple interactions, MI. For this reason we search for D* Mesons, in order to tag the charm quark, and we restrict ourselves in the region: Q 2 2 . For the theoretical calculations we use two Monte Carlo event generators: RAPGAP 3.1 and PYTHIA 6.2. Heavy quark production provides a large hard scale and therefore a small α s , which allows to test the perturbative QCD theory. On the other hand, MI has been proven to be important in hadron-hadron collisions. In this thesis, using MC event generators, we search for possible signals of MI in heavy quark production in electron-proton, ep, collisions. The thesis begins with a Theoretical Overview, with an introduction to ep collisions physics and the heavy quark photoproduction. We also give an introduction to the MI model included in PYTHIA. The next chapter introduces the concept of jet and presents some methods for the Heavy Quark Identification. After these two theoretical chapters there is a study of the direct and photon resolved processes, as well as the parton showering with RAPGAP. Since this thesis is oriented to the study of MI, PYTHIA plays a very important role because it includes a MI model also for ep collisions. Therefore, the fourth chapter is oriented to study the different steps in the event generation in PYTHIA. Chapter 7 is a D* Meson photoproduction study, where we include a comparison between the data, taken from the PhD Thesis of Gero Flucke. Finally, chapter 8 is a search for possible signals on MI. In hadron-hadron collisions it is clear that MI play a role. In ep collisions it is not so clear although MI could play a role in resolved photon events. The aim of this chapter is to find signals where HERA measurements could be sensitive to MI. (orig.)

Heavy quarks and their experimental consequences

International Nuclear Information System (INIS)

Appelquist, T.

1975-09-01

Recent theoretical work on heavy quark dynamics is reviewed. In the context of a color gauge theory of strong interactions, the structure of heavy quark-antiquark bound states and their decay properties is discussed. The emphasis is on the dynamical differences between heavy and light quark bound states. It is suggested that the former will more directly reflect the structure of the underlying field theory

Quark-antiquark potentials from QCD and quarkonium spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Laschka, Alexander

2012-12-11

This work examines the interaction between a heavy quark and its antiquark. By combining perturbative and non-perturbative methods, interaction potentials with an extended range of validity are derived from quantum chromodynamics. Using these potentials the spectra of the quarkonium bound states are calculated and compared with experimental results. This provides a new approach for determining the masses of the charm and bottom quark.

Importance of Nonperturbative QCD Parameters for Bottom Mesons

Directory of Open Access Journals (Sweden)

A. Upadhyay

2014-01-01

Full Text Available The importance of nonperturbative quantum chromodynamics (QCD parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=1/2+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.

Non-perturbative renormalization of three-quark operators

Energy Technology Data Exchange (ETDEWEB)

Goeckeler, Meinulf [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, Roger [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Kaltenbrunner, Thomas [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)

2008-10-15

High luminosity accelerators have greatly increased the interest in semi-exclusive and exclusive reactions involving nucleons. The relevant theoretical information is contained in the nucleon wavefunction and can be parametrized by moments of the nucleon distribution amplitudes, which in turn are linked to matrix elements of local three-quark operators. These can be calculated from first principles in lattice QCD. Defining an RI-MOM renormalization scheme, we renormalize three-quark operators corresponding to low moments non-perturbatively and take special care of the operator mixing. After performing a scheme matching and a conversion of the renormalization scale we quote our final results in the MS scheme at {mu}=2 GeV. (orig.)

1-- and 0++ heavy four-quark and molecule states in QCD

International Nuclear Information System (INIS)

Albuquerque, R.M.; Fanomezana, F.; Narison, S.; Rabemananjara, A.

2012-01-01

We estimate the masses of the 1 -- heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in α s but including non-perturbative terms up to the complete dimension-six condensate contributions. This approach allows to fix more precisely the value of the QCD continuum threshold (often taken ad hoc) at which the optimal result is extracted. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. We also study the effects of the heavy quark mass definitions on these LO results. The SU(3) mass-splittings of about (50-110) MeV and the ones of about (250-300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavor independent. The mass predictions summarized in Table 4 are compared with the ones in the literature (when available) and with the three Y c (4260,4360,4660) and Y b (10890)1 -- experimental candidates. We conclude (to this order approximation) that the lowest observed state cannot be a pure1 -- four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0 ++ four-quark and molecule states which are about (0.5-1) GeV heavier than the corresponding 1 -- states, while the splittings between the 0 ++ lowest ground state and the 1st radial excitation is about (300-500) MeV. We complete the analysis by estimating the decay constants of the 1 -- and 0 ++ four-quark states which are tiny and which exhibit a 1/M Q behavior. Our predictions can be further tested using some alternative non-perturbative approaches or/and at LHC b and some other hadron factories.

A diquark model for baryons containing one heavy quark

International Nuclear Information System (INIS)

Ebert, D.; Feldmann, T.; Kettner, C.; Reinhardt, H.

1995-06-01

We present a phenomenological ansatz for coupling a heavy quark with two light quarks to form a heavy baryon. The heavy quark is treated in the heavy mass limit, and the light quark dynamics is approximated by propagating scalar and axial vector 'diquarks'. The resulting effective lagrangian, which incorporates heavy quark and chiral symmetry, describes interactions of heavy baryons with Goldstone bosons in the low energy region. As an application, the Isgur-Wise formfactors are estimated. (orig.)

Heavy quark photoproduction in ultraperipheral heavy ion collisions

International Nuclear Information System (INIS)

Klein, Spencer R.; Nystrand, Joakim; Vogt, Ramona

2002-01-01

Heavy quarks are copiously produced in ultraperipheral heavy ion collisions. In the strong electromagnetic fields, cc-bar and bb-bar are produced by photonuclear and two-photon interactions. Hadroproduction can also occur in grazing interactions. We calculate the total cross sections and the quark transverse momentum and rapidity distributions, as well as the QQ-bar invariant mass spectra from the three production channels. We consider AA and pA collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider. We discuss techniques for separating the three processes and describe how the AA to pA production ratios might be measured accurately enough to study nuclear shadowing

Soft Gluon Radiation off Heavy Quarks beyond Eikonal Approximation

International Nuclear Information System (INIS)

Mazumder, Surasree; Bhattacharyya, Trambak; Abir, Raktim

2016-01-01

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.

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.

Quasilocal quark models as effective theory of non-perturbative QCD

International Nuclear Information System (INIS)

Andrianov, A.A.

2006-01-01

We consider the Quasilocal Quark Model of NJL type (QNJLM) as effective theory of non-perturbative QCD including scalar (S), pseudo-scalar (P), vector (V) and axial-vector (A) four-fermion interaction with derivatives. In the presence of a strong attraction in the scalar channel the chiral symmetry is spontaneously broken and as a consequence the composite meson states are generated in all channels. With the help of Operator Product Expansion the appropriate set of Chiral Symmetry Restoration (CSR) Sum Rules in these channels are imposed as matching rules to QCD at intermediate energies. The mass spectrum and some decay constants for ground and excited meson states are calculated

Heavy quark spectroscopy and decay

International Nuclear Information System (INIS)

Schindler, R.H.

1987-01-01

The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be an experimentalist's review of the subject. In the first of two lectures, the existing data on the spectroscopy of the bound c anti c and b anti b systems will be discussed. Emphasis is placed on comparisons with the theoretical models. The second lecture covers the rapidly changing subject of the decays of heavy mesons (c anti q and b anti q), and their excited states. In combination, the spectroscopy and decays of heavy quarks are shown to provide interesting insights into both the strong and electroweak interactions of the heavy quarks. 103 refs., 39 figs

Phenomenology of heavy leptons and heavy quarks

International Nuclear Information System (INIS)

Gilman, F.J.

1978-11-01

The review of the quark and lepton family includes properties of the tau, SU(2) x U(1) classification of the tau and its decays, heavier leptons, the spectroscopy of heavy hadrons composed of quarks, their strong and electromagnetic decays, the weak interaction properties of the c, b, and t quarks, and the decays of hadrons containing them expected within the context of the standard SU(2) x U(1) model. 76 references

Nonperturbative QCD with modern tools

International Nuclear Information System (INIS)

Roberts, C.D.

1998-01-01

In these lectures the author introduces and explores a range of topics of contemporary interest in hadronic physics: from what drives the formation of a nonzero quark condensate to the effect that mechanism has on light and heavy meson form factors and the properties of the quark-gluon plasma. The trail leads naturally through a discussion of confinement, dynamical chiral symmetry breaking and bound state structure: phenomena that require nonperturbative methods for their explanation. In all of this, the necessary and necessarily momentum-dependent modification of the quark and gluon propagators plays a significant role

Nonperturbative aspects of Yang-Mills theory

International Nuclear Information System (INIS)

Schleifenbaum, Wolfgang

2008-01-01

The subject of this thesis is the theory of strong interactions of quarks and gluons, with particular emphasis on nonperturbative aspects of the gluon sector. Continuum methods are used to investigate in particular the confinement phenomenon. Confinement which states that the elementary quarks and gluons cannot be detected as free particles requires an understanding of large-scale correlations. In perturbation theory, only short-range correlations can be reliably described. A nonperturbative approach is given by the set of integral Dyson Schwinger equations involving all Green functions of the theory. A solution for the gluon propagator is obtained in the infrared and ultraviolet asymptotic limits. In chapter 1, redundant degrees of freedom of the Yang Mills gauge theory are removed by fixing the Weyl and Coulomb gauge prior to quantization. The constrained quantization in the Dirac bracket formalism is then performed explicitly to produce the quantized Yang Mills Hamiltonian. The asymptotic infrared limits of Coulomb gauge correlation functions are studied analytically in chapter 2 in the framework of the Gribov Zwanziger confinement scenario. The Coulomb potential between heavy quarks as part of the Yang Mills Hamiltonian is calculated in this limit. A connection between the infrared limits of Coulomb and Landau gauge is established. The Hamiltonian derived paves the way in chapter 3 for finding the Coulomb gauge vacuum wave functional by means of the variational principle. Numerical solutions for the propagators in this vacuum state are discussed and seen to reproduce the anticipated infrared limit. The discussion is extended to the vertex functions. The effect of the approximations on the results is examined. Chapter 4 is mainly devoted to the ultraviolet behavior of the propagators. The discussion is issued in both Coulomb and Landau gauge. A nonperturbative running coupling is defined and calculated. The ultraviolet tails of the variational solutions from

Nonperturbative aspects of Yang-Mills theory

Energy Technology Data Exchange (ETDEWEB)

Schleifenbaum, Wolfgang

2008-07-01

The subject of this thesis is the theory of strong interactions of quarks and gluons, with particular emphasis on nonperturbative aspects of the gluon sector. Continuum methods are used to investigate in particular the confinement phenomenon. Confinement which states that the elementary quarks and gluons cannot be detected as free particles requires an understanding of large-scale correlations. In perturbation theory, only short-range correlations can be reliably described. A nonperturbative approach is given by the set of integral Dyson Schwinger equations involving all Green functions of the theory. A solution for the gluon propagator is obtained in the infrared and ultraviolet asymptotic limits. In chapter 1, redundant degrees of freedom of the Yang Mills gauge theory are removed by fixing the Weyl and Coulomb gauge prior to quantization. The constrained quantization in the Dirac bracket formalism is then performed explicitly to produce the quantized Yang Mills Hamiltonian. The asymptotic infrared limits of Coulomb gauge correlation functions are studied analytically in chapter 2 in the framework of the Gribov Zwanziger confinement scenario. The Coulomb potential between heavy quarks as part of the Yang Mills Hamiltonian is calculated in this limit. A connection between the infrared limits of Coulomb and Landau gauge is established. The Hamiltonian derived paves the way in chapter 3 for finding the Coulomb gauge vacuum wave functional by means of the variational principle. Numerical solutions for the propagators in this vacuum state are discussed and seen to reproduce the anticipated infrared limit. The discussion is extended to the vertex functions. The effect of the approximations on the results is examined. Chapter 4 is mainly devoted to the ultraviolet behavior of the propagators. The discussion is issued in both Coulomb and Landau gauge. A nonperturbative running coupling is defined and calculated. The ultraviolet tails of the variational solutions from

Non-perturbative Aspects of QCD and Parameterized Quark Propagator

Institute of Scientific and Technical Information of China (English)

HAN Ding-An; ZHOU Li-Juan; ZENG Ya-Guang; GU Yun-Ting; CAO Hui; MA Wei-Xing; MENG Cheng-Ju; PAN Ji-Huan

2008-01-01

Based on the Global Color Symmetry Model, the non-perturbative QCD vacuum is investigated in theparameterized fully dressed quark propagator. Our theoretical predictions for various quantities characterized the QCD vacuum are in agreement with those predicted by many other phenomenological QCD inspired models. The successful predictions clearly indicate the extensive validity of our parameterized quark propagator used here. A detailed discussion on the arbitrariness in determining the integration cut-off parameter of# in calculating QCD vacuum condensates and a good method, which avoided the dependence of calculating results on the cut-off parameter is also strongly recommended to readers.

Estimates for the parameters of the heavy quark expansion

Energy Technology Data Exchange (ETDEWEB)

Heinonen, Johannes; Mannel, Thomas [Universitaet Siegen (Germany)

2015-07-01

We give improved estimates for the non-perturbative parameters appearing in the heavy quark expansion for inclusive decays. While the parameters appearing in low orders of this expansion can be extracted from data, the number of parameters in higher orders proliferates strongly, making a determination of these parameters from data impossible. Thus, one has to rely on theoretical estimates which may be obtained from an insertion of intermediate states. We refine this method and attempt to estimate the uncertainties of this approach.

Baryon interactions from lattice QCD with physical quark masses - Nuclear forces and ΞΞ forces -

Science.gov (United States)

Doi, Takumi; Iritani, Takumi; Aoki, Sinya; Gongyo, Shinya; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Ishii, Noriyoshi; Miyamoto, Takaya; Nemura, Hidekatsu; Sasaki, Kenji

2018-03-01

We present the latest lattice QCD results for baryon interactions obtained at nearly physical quark masses. Nf = 2 + 1 nonperturbatively O(a)-improved Wilson quark action with stout smearing and Iwasaki gauge action are employed on the lattice of (96a)4 ≃(8.1fm)4 with a-1 ≃2.3 GeV, where mπ ≃146 MeV and mK ≃525 MeV. In this report, we study the two-nucleon systems and two-Ξ systems in 1S0 channel and 3S1-3D1 coupled channel, and extract central and tensor interactions by the HAL QCD method. We also present the results for the NΩ interaction in 5S2 channel which is relevant to the NΩ pair-momentum correlation in heavy-ion collision experiments.

Heavy quarks - experimental

International Nuclear Information System (INIS)

Hollebeek, R.

1990-01-01

The purpose of these lectures, given at the 1989 SLAC Summer School, was to discuss the experimental aspects of heavy quark production. A companion set of lectures on the theoretical point of view were to be given by Keith Ellis. An experimentalist should gather together the measurements which have been made by various groups, compare, contrast and tabulate them, and if possible point out the ways in which these measurements confirm or contradict current theories. Here the authors has tried to do this, although the reader who expects to find here the latest of all experimental measurements should probably be forewarned that the field is moving extremely rapidly. In some cases, he has added and updated materials where crucial new information became available after or during the summer of 1989, but not in all cases. He has concentrated on trying to select those measurements which are at the moment most crucial in refining our understanding of heavy quarks as opposed to those which merely measure things which are perhaps too complicated to be enlightening at the moment. While theorists worry primarily about production mechanisms, cross sections, QCD corrections, and to some extent about signatures, the experimentalist must determine which measurements he is interested in making, and which signatures for heavy quark production are realistic and likely to produce results which will shed some new light on the underlying production model without undo theoretical complications. Experimentalists also need to evaluate the available experimental equipment, both machines and detectors to find the best way to investigate the properties of heavy quarks. In many cases, the things which we would like to measure are severely restricted by what we can measure. Nevertheless, many properties of heavy quark production and decay can be measured, and the results have already taught us much about the weak interactions and QCD

1{sup --} and 0{sup ++} heavy four-quark and molecule states in QCD

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, R.M., E-mail: rma@if.usp.br [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05389-970 Sao Paulo, SP (Brazil); Laboratoire Particules et Univers de Montpellier, CNRS-IN2P3, Case 070, Place Eugene Bataillon, 34095 Montpellier (France); Fanomezana, F., E-mail: fanfenos@yahoo.fr [Institute of High-Energy Physics of Madagascar (iHEP-MAD), University of Antananarivo (Madagascar); Narison, S., E-mail: snarison@yahoo.fr [Laboratoire Particules et Univers de Montpellier, CNRS-IN2P3, Case 070, Place Eugene Bataillon, 34095 Montpellier (France); Rabemananjara, A., E-mail: achris_01@yahoo.fr [Institute of High-Energy Physics of Madagascar (iHEP-MAD), University of Antananarivo (Madagascar)

2012-08-29

We estimate the masses of the 1{sup --} heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in {alpha}{sub s} but including non-perturbative terms up to the complete dimension-six condensate contributions. This approach allows to fix more precisely the value of the QCD continuum threshold (often taken ad hoc) at which the optimal result is extracted. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. We also study the effects of the heavy quark mass definitions on these LO results. The SU(3) mass-splittings of about (50-110) MeV and the ones of about (250-300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavor independent. The mass predictions summarized in Table 4 are compared with the ones in the literature (when available) and with the three Y{sub c}(4260,4360,4660) and Y{sub b}(10890)1{sup --} experimental candidates. We conclude (to this order approximation) that the lowest observed state cannot be a pure1{sup --} four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0{sup ++} four-quark and molecule states which are about (0.5-1) GeV heavier than the corresponding 1{sup --} states, while the splittings between the 0{sup ++} lowest ground state and the 1st radial excitation is about (300-500) MeV. We complete the analysis by estimating the decay constants of the 1{sup --} and 0{sup ++} four-quark states which are tiny and which exhibit a 1/M{sub Q} behavior. Our predictions can be further tested using some alternative non-perturbative approaches or/and at LHC{sub b} and some other hadron factories.

Heavy quarks and leptons

International Nuclear Information System (INIS)

Azimov, Ya.I.; Khoze, V.A.

1979-01-01

Experimental results which proved the reality of quarks are reviewed along with further experiments broadening the representation of quarks and leptons and providing the basis to develop the theory of elementary particles. The discovery of the J/psi particle is noted to give rise to the discovery of c-quark, the existance of which is confirmed by the discovery of charmed hadrons. The main aspects of quantum chromodynamics explaining the mechanism of strong interaction of quarks are considered along with those of the Weinberg-Salam theory proposed to describe weak and electromagnetic interactions of quarks and leptons. Experimental data testifying to the existance of heavy tausup(+-) leptons are presented. The history of discovery of γ mesons and of a new heavier b-quark is described. Perspectives for studying elementary particles are discussed. Further studies of γ mesons, discovery and investigation of charmed particles are noted to be immediate tasks along with the search for manifestation of t-quark considered to be a partner of b-quark from the viewpoint of the Weinberg-Salam model

Heavy quark fragmentation functions in the heavy quark effective theory

International Nuclear Information System (INIS)

Martynenko, A.P.; Saleev, V.A.

1996-01-01

The fragmentation of b-bar-antiquark into polarized B c * -mesons and b-quark into P-wave (c-bar b) states in the Heavy Quark Effective Theory. The heavy quark fragmentation functions in longitudinally and transversely polarized S-wave b-bar c-states and P-wave mesons containing b-, c-quarks also, with the exact account of corrections of first order in 1/m b . 20 refs., 2 figs

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.

Non-perturbative renormalization of HQET and QCD

International Nuclear Information System (INIS)

Sommer, Rainer

2003-01-01

We discuss the necessity of non-perturbative renormalization in QCD and HQET and explain the general strategy for solving this problem. A few selected topics are discussed in some detail, namely the importance of off shell improvement in the MOM-scheme on the lattice, recent progress in the implementation of finite volume schemes and then particular emphasis is put on the recent idea to carry out a non-perturbative renormalization of the Heavy Quark Effective Theory (HQET)

Heavy quark spectroscopy

International Nuclear Information System (INIS)

Rosner, J.L.

1985-10-01

New experimental and theoretical developments in heavy quark spectroscopy are reviewed. From studies of J/psi decays, the eta' is found to have some ''glue'' or other inert component, while the iota (a glueball candidate) probably contains some quarks as well. The xi(2.2) persists in new Mark III data, but is not seen by the DM2 collaboration. The production of charmonium states by anti pp reactions is reviewed. First evidence for a P- wave charmed meson, D(2420), has been presented by the ARGUS group. Radiative UPSILON decay studies fail to confirm the zeta(8.3) and begin to place useful limits on Higgs bosons. First results from an experiment at Fermilab on low-background hadronic production of UPSILON states are shown. Accurate measurements of chi/sub b/(1P) masses by the ARGUS collaboration are noted, and interpreted as favoring scalar quark confinement. Studies of t and other heavy quarks will probe the q anti q interaction below 0.05 fm, are likely to be strongly affected by t anti t-Z interference, and can provide varied information on Higgs bosons. 144 refs., 21 figs

Heavy quarks and CP: Moriond 1985

International Nuclear Information System (INIS)

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

Elliptic flow and energy loss of heavy quarks in ultrarelativistic heavy ion collisions

International Nuclear Information System (INIS)

Uphoff, Jan; Fochler, Oliver; Greiner, Carsten; Xu, Zhe

2011-01-01

The space-time propagation of heavy quarks in ultrarelativistic heavy ion collisions is studied within the partonic transport model Boltzmann approach of multiparton scatterings (BAMPS). In this model heavy quarks interact with the partonic medium via binary scatterings. The cross sections for these interactions are calculated with leading-order perturbative QCD, but feature a more precise Debye screening derived within the hard thermal loop approximation and obey the running of the coupling. Within this framework the elliptic flow and the nuclear modification factor of heavy quarks are computed for the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC) energies and compared to available experimental data. It is found that binary scatterings alone cannot reproduce the data and therefore radiative corrections have to be taken into account.

Heavy baryons in the relativistic quark model

International Nuclear Information System (INIS)

Ebert, D.; Faustov, R.N.; Galkin, V.O.; Martynenko, A.P.; Saleev, V.A.

1996-07-01

In the framework of the relativistic quasipotential quark model the mass spectrum of baryons with two heavy quarks is calculated. The quasipotentials for interactions of two quarks and of a quark with a scalar and axial vector diquark are evaluated. The bound state masses of baryons with J P =1/2 + , 3/2 + are computed. (orig.)

A higher twist correction to heavy quark production

International Nuclear Information System (INIS)

Brodsky, S.J.; Gunion, J.F.; Soper, D.E.

1987-06-01

The leading twist prediction for heavy quark production and a model for a higher twist correction that may be important for charm production was discussed. The correction arises from the interaction of the charm quark with spectator quarks

Heavy quark and sparticle phenomenology

International Nuclear Information System (INIS)

Barger, V.

1985-01-01

Data from the CERN p anti p collider provide a new avenue for the study of heavy-quark production and possibly also provide the first indication for the sparticles of supersymmetry. This discussion of the associated phenomenology begins with charm and bottom quarks, proceeds to the strategies that lead to top quark identification, and concludes with possible supersymmetry scenarios to explain the events observed by the UA1 collaboration with large missing transverse momentum. The fusion predictions of single muon and dimuon rates are in the ballpark of UA1 observations. The discovery of isolated like-sign dimuons is at present an anomaly. The p anti p collider is a good place to do B physics, and answer the question of whether B 0 - anti B 0 mixing occurs. Also, it should soon be possible to identify a few dimuon events of W → t anti b and t anti t origins. Finally, enhanced charm in jets, if established, would have to be ascribed to non-perturbative QCD effects. In conclusion, if the UA1 monojets are of supersymmetry origin, then squark and gluino masses are already tightly constrained and dijet events with large missing transverse momentum should help distinguish between the two most promising scenarios. The top signal is not being faked by sparticles. (Nogami, K.)

Heavy quark hadron mass scale

International Nuclear Information System (INIS)

Anderson, J.T.

1994-01-01

Without the spin interactions the hardron masses within a multiplet are degenerate. The light quark hadron degenerate mulitplet mass spectrum is extended from the 3 quark ground state multiplets at J P =0 - , 1/2 + , 1 - to include the excited states which follow the spinorial decomposition of SU(2)xSU(2). The mass scales for the 4, 5, 6, .. quark hadrons are obtained from the degenerate multiplet mass m 0 /M=n 2 /α with n=4, 5, 6, .. The 4, 5, 6, .. quark hadron degenerate multiplet masses follow by splitting of the heavy quark mass scales according to the spinorial decomposition of SU(2)xSU(2). (orig.)

Non-perturbative renormalization of static-light four-fermion operators in quenched lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Palombi, F. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Papinutto, M.; Pena, C. [CERN, Geneva (Switzerland). Physics Dept., Theory Div.; Wittig, H. [Mainz Univ. (Germany). Inst. fuer Kernphysik

2007-06-15

We perform a non-perturbative study of the scale-dependent renormalization factors of a multiplicatively renormalizable basis of {delta}B=2 parity-odd four-fermion operators in quenched lattice QCD. Heavy quarks are treated in the static approximation with various lattice discretizations of the static action. Light quarks are described by nonperturbatively O(a) improved Wilson-type fermions. The renormalization group running is computed for a family of Schroedinger functional (SF) schemes through finite volume techniques in the continuum limit. We compute non-perturbatively the relation between the renormalization group invariant operators and their counterparts renormalized in the SF at a low energy scale. Furthermore, we provide non-perturbative estimates for the matching between the lattice regularized theory and all the SF schemes considered. (orig.)

Non-perturbative running of quark masses in three-flavour QCD

CERN Document Server

Campos, Isabel; Pena, Carlos; Preti, David; Ramos, Alberto; Vladikas, Anastassios

2016-01-01

We present our preliminary results for the computation of the non-perturbative running of renormalized quark masses in $N_f = 3$ QCD, between the electroweak and hadronic scales, using standard finite-size scaling techniques. The computation is carried out to very high precision, using massless $\\mathcal{O}(a)$-improved Wilson quarks. Following the strategy adopted by the ALPHA Collaboration for the running coupling, different schemes are used above and below a scale $\\mu_0 \\sim m_b$, which differ by using either the Schr\\"odinger Functional or Gradient Flow renormalized coupling. We discuss our results for the running in both regions, and the procedure to match the two schemes.

Heavy-quark fragmentation functions in the effective theory of heavy quarks

International Nuclear Information System (INIS)

Martynenko, A.P.; Saleev, V.A.

1996-01-01

The effective theory of heavy quarks is used to study b-bar-antiquark fragmentation in polarized Bc* mesons and b-quark fragmentation into P-wave (c-barb) states. The functions of heavy-quark fragmentation into longitudinally and transversely polarized S-wave (b-barc) states and into P-wave mesons containing b and c quarks are calculated. First-order corrections in 1/mb are taken into account exactly in these calculations. The results are shown to be consistent with the corresponding QCD calculations

The significance of the heavy top quark

International Nuclear Information System (INIS)

Simmons, Elizabeth H.

1997-01-01

Experiment shows that the top quark is far heavier than the other elementary fermions. This finding has stimulated research on theories of electroweak and flavor symmetry breaking that include physics beyond the standard model. Efforts to accommodate a heavy top quark within existing frameworks have revealed constraints on model-building. Other investigations have started from the premise that a large top quark mass could signal a qualitative difference between the top quark and other fermions, perhaps in the form of new interactions peculiar to the top quark. Such new dynamics may also help answer existing questions about electroweak and flavor physics. This talk explores the implications of the heavy top quark in the context of weakly-coupled (e.g., SUSY) and strongly-coupled (e.g., technicolor) theories of electroweak symmetry breaking

A path integral for heavy-quarks in a hot plasma

CERN Document Server

Beraudo, A.; Faccioli, P.; Garberoglio, G.; 10.1016/j.nuclphysa.2010.06.007

2010-01-01

We propose a model for the propagation of a heavy-quark in a hot plasma, to be viewed as a first step towards a full description of the dynamics of heavy quark systems in a quark-gluon plasma, including bound state formation. The heavy quark is treated as a non relativistic particle interacting with a fluctuating field, whose correlator is determined by a hard thermal loop approximation. This approximation, which concerns only the medium in which the heavy quark propagates, is the only one that is made, and it can be improved. The dynamics of the heavy quark is given exactly by a quantum mechanical path integral that is calculated in this paper in the Euclidean space-time using numerical Monte Carlo techniques. The spectral function of the heavy quark in the medium is then reconstructed using a Maximum Entropy Method. The path integral is also evaluated exactly in the case where the mass of the heavy quark is infinite; one then recovers known results concerning the complex optical potential that controls the ...

Di-Jet Conical Correlations Associated with Heavy Quark Jets in anti-de Sitter Space/Conformal Field Theory Correspondence

International Nuclear Information System (INIS)

Noronha, Jorge; Gyulassy, Miklos; Torrieri, Giorgio

2009-01-01

We show that far zone Mach and diffusion wake 'holograms' produced by supersonic strings in anti-de Sitter space/conformal field theory (AdS/CFT) correspondence do not lead to observable conical angular correlations in the strict N c →∞ supergravity limit if Cooper-Frye hadronization is assumed. However, a special nonequilibrium 'neck' zone near the jet is shown to produce an apparent sonic boom azimuthal angle distribution that is roughly independent of the heavy quark's velocity. Our results indicate that a measurement of the dependence of the away-side correlations on the velocity of associated identified heavy quark jets at the BNL Relativistic Heavy Ion Collider and CERN LHC will provide a direct test of the nonperturbative dynamics involved in the coupling between jets and the strongly coupled quark-gluon plasma implied by AdS/CFT correspondence

Di-jet conical correlations associated with heavy quark jets in anti-de sitter space/conformal field theory correspondence.

Science.gov (United States)

Noronha, Jorge; Gyulassy, Miklos; Torrieri, Giorgio

2009-03-13

We show that far zone Mach and diffusion wake "holograms" produced by supersonic strings in anti-de Sitter space/conformal field theory (AdS/CFT) correspondence do not lead to observable conical angular correlations in the strict N_{c}-->infinity supergravity limit if Cooper-Frye hadronization is assumed. However, a special nonequilibrium "neck" zone near the jet is shown to produce an apparent sonic boom azimuthal angle distribution that is roughly independent of the heavy quark's velocity. Our results indicate that a measurement of the dependence of the away-side correlations on the velocity of associated identified heavy quark jets at the BNL Relativistic Heavy Ion Collider and CERN LHC will provide a direct test of the nonperturbative dynamics involved in the coupling between jets and the strongly coupled quark-gluon plasma implied by AdS/CFT correspondence.

Heavy mesons spectroscopy and new quarks

International Nuclear Information System (INIS)

Carvalho, H.F. de.

1977-12-01

The spectroscopy of new heavy mesons with masses above 2.8 GeV in the context of the asymptoticallty free gauge theories is analysed. To this end a power -law confinement potential is chosen. It is shown that the charmonium spectroscopy is best described by a potential where the exponent is around 0.5. It is observed that the spin-spin interaction is problematic. A possible interpretation of the γ resonances in the neighbourhood of 10 GeV is also discussed. The possible consequences of the existence of heavy quarks beyond charm with special reference to the processes initiated by neutral currents is also discussed. The present results on processes initiated by neutral current effects does not require introduction of right-handed heavy quarks beyond charm. Inclusion of the sea-quark contribution improves the agreements of the results of the Salam-Weinberg model with the recently observed results from CERN where 'ν anomaly' was not seen. The recently discovered γ resonances probably indicate the existence of heavy quarks probably with left handed coupling. Some preliminary study of this possibility was also carried out. (Author) [pt

Quark interchange model of baryon interactions

Energy Technology Data Exchange (ETDEWEB)

Maslow, J.N.

1983-01-01

The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point-like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and it is assumed that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (q anti-q) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of YN scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers.

Quark interchange model of baryon interactions

International Nuclear Information System (INIS)

Maslow, J.N.

1983-01-01

The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point-like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and it is assumed that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (q anti-q) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of YN scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers

Transverse Momentum Distributions for Heavy Quark Pairs

OpenAIRE

Berger, Edmond L.; Meng, Ruibin

1993-01-01

We study the transverse momentum distribution for a $pair$ of heavy quarks produced in hadron-hadron interactions. Predictions for the large transverse momentum region are based on exact order $\\alpha_s^3$ QCD perturbation theory. For the small transverse momentum region, we use techniques for all orders resummation of leading logarithmic contributions associated with initial state soft gluon radiation. The combination provides the transverse momentum distribution of heavy quark pairs for all...

Heavy-Quark Production

CERN Document Server

Frixione, Stefano; Nason, Paolo; Ridolfi, Giovanni

1997-01-01

We review the present theoretical and experimental status of heavy quark production in high-energy collisions. In particular, we cover hadro- and photoproduction at fixed target experiments, at HERA and at the hadron colliders, as well as aspects of heavy quark production in e+e- collisions at the Z0 peak.

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.

Light-quark, heavy-quark systems: An update

International Nuclear Information System (INIS)

Grinstein, B.

1993-01-01

The author reviews many of the recently developed applications of Heavy Quark Effective Theory techniques. After a brief update on Luke's theorm, he describes striking relations between heavy baryon form factors, and how to use them to estimate the accuracy of the extraction of |B cb |. He discusses factorization and compares with experiment. An elementary presentation, with sample applications, of reparametrization invariance comes next. The final and most extensive chapter in this review deals with phenomenological lagrangians that incorporate heavy-quark spin-flavor as well as light quark chiral symmetries. He compiles many interesting results and discuss the validity of the calculations

Light-quark, heavy-quark systems: An update

Science.gov (United States)

Grinstein, B.

1993-06-01

We review many of the recently developed applications of Heavy Quark Effective Theory techniques. After a brief update on Luke's theorem, we describe striking relations between heavy baryon form factors, and how to use them to estimate the accuracy of the extraction of (vert bar)V(sub cb)(vert bar). We discuss factorization and compare with experiment. An elementary presentation, with sample applications, of reparametrization invariance comes next. The final and most extensive chapter in this review deals with phenomenological lagrangians that incorporate heavy-quark spin-flavor as well as light quark chiral symmetries. We compile many interesting results and discuss the validity of the calculations.

The baryon-baryon interaction in a modified quark model

International Nuclear Information System (INIS)

Zhang Zongye; Faessler, Amand; Straub, U.; Glozman, L.Ya.

1994-01-01

The quark-cluster model with coupling constants constraint by chiral symmetry is extended to include strange quarks. In this model, besides the confinement and one-gluon exchange potentials, the pseudoscalar mesons and sigma (σ) meson exchanges are included as the nonperturbative effect. Using this interaction we studied the binding energy of the deuteron, the NN scattering phase shifts and the hyperon-nucleon cross sections in the framework of the resonating group method (RGM). The results are reasonably consistent with experiments. ((orig.))

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.

Heavy Quark and Quarkonium Transport in High Energy Nuclear Collisions

International Nuclear Information System (INIS)

Zhou, Kai; Dai, Wei; Xu, Nu; Zhuang, Pengfei

2016-01-01

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.

1{sup −−} and 0{sup ++} heavy four-quark and molecule states in QCD

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, R.M., E-mail: rma@if.usp.br [Instituto de Física, Universidade de São Paulo, C.P. 66318, 05389-970 São Paulo, SP (Brazil); Laboratoire Particules et Univers de Montpellier, CNRS-IN2P3, Case 070, Place Eugène Bataillon, 34095 - Montpellier (France); Fanomezana, F., E-mail: fanfenos@yahoo.fr [Institute of High-Energy Physics of Madagascar (iHEP-MAD), University of Antananarivo (Madagascar); Narison, S., E-mail: snarison@yahoo.fr [Laboratoire Particules et Univers de Montpellier, CNRS-IN2P3, Case 070, Place Eugène Bataillon, 34095 - Montpellier (France); Rabemananjara, A., E-mail: achris_01@yahoo.fr [Institute of High-Energy Physics of Madagascar (iHEP-MAD), University of Antananarivo (Madagascar)

2013-01-15

We estimate the masses of the 1{sup −−} heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in α{sub s} but including non-perturbative terms up to the complete dimension-six condensate contributions. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. The SU(3) mass-splittings of about (50–110) MeV and the ones of about (250–300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavour independent. The mass predictions summarized in Table 2 are compared with the ones in the literature (when available) and with the three Y{sub c}(4260,4360,4660) and Y{sub b}(10890)1{sup −−} experimental candidates. We conclude that the lowest observed state cannot be a pure1{sup −−} four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0{sup ++} four-quark and molecule states which are about (0.5–1) GeV heavier than the corresponding 1{sup −−} states, while the splittings between the 0{sup ++} lowest ground state and the 1st radial excitation is about (300–500) MeV. We complete the analysis by estimating the decay constants of the 1{sup −−} and 0{sup ++} four-quark states. Our predictions can be tested using some alternative non-perturbative approaches or/and at LHC{sub b} or some other hadron factories.

Effects of final-state interaction and screening on strange and heavy quark production

Energy Technology Data Exchange (ETDEWEB)

Wong, Cheuk-Yin [Oak Ridge National Lab., TN (United States); Chatterjee, L. [Oak Ridge National Lab., TN (United States)]|[Tennessee Univ., Knoxville, TN (United States)]|[Jadavpur Univ., Calcutta (India)

1996-10-01

Final-state interaction and screening have a great influence on {ital q{anti q}} production cross sections, which are important quantities in many problems in quark-gluon plasma physics. They lead to an enhancement of the cross section for a {ital q{anti q}} color-singlet state and a suppression for a color-octet state. The effects are large near the production threshold. The presence of screening gives rise to resonances for {ital q{anti q}} production just above the threshold at specific plasma temperatures. These resonances, especially {ital c{anti c}} and {ital b{anti b}} resonances, may be utilized to search for the quark-gluon plasma by studying the temperature dependence of heavy-quark pair production just above the threshold.

Heavy quark production in quantum chromodynamics

International Nuclear Information System (INIS)

Brodsky, S.J.

1986-09-01

For very heavy quark masses, the inclusive hadronic production of hadron pairs containing heavy quarks is predicted to be governed by QCD fusion subprocesses. For intermediate mass scales other QCD mechanisms can be important including higher-twist intrinsic contributions and low relative velocity enchancements, possibly accounting for the anomalies observed in charm hadroproduction, such as the nuclear number dependence, the longitudinal momentum distributions, and beam flavor dependence. We also discuss scaling laws for exclusive processes involving heavy quarks and diffractive excitation into heavy quark systems

Effective meson lagrangian with chiral and heavy quark symmetries from quark flavor dynamics

International Nuclear Information System (INIS)

Ebert, D.; Feldmann, T.; Friedrich, R.; Reinhardt, H.

1994-06-01

By bosonization of an extended NJL model we derive an effective meson theory which describes the interplay between chiral symmetry and heavy quark dynamics. This effective theory is worked out in the low-energy regime using the gradient expansion. The resulting effective lagrangian describes strong and weak interactions of heavy B and D mesons with pseudoscalar Goldstone bosons and light vector and axial-vector mesons. Heavy meson weak decay constants, coupling constants and the Isgur-Wise function are predicted in terms of the model parameters partially fixed from the light quark sector. Explicit SU(3) F symmetry breaking effects are estimated and, if possible, confronted with experiment. (orig.)

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.)

Screening of heavy quarks and hadrons at finite temperature and density

International Nuclear Information System (INIS)

Doering, M.

2006-01-01

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 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 c . The hadron screening masses are consistent with the free quark propagation in the large temperature regime. (orig.)

Heavy quark mass effects and improved tests of the flavor independence of strong interactions

Energy Technology Data Exchange (ETDEWEB)

Burrows, P.N. [Univ. of Oxford (United Kingdom); SLD Collaboration

1998-08-01

A review is given of latest results on tests of the flavor independence of strong interactions. Heavy quark mass effects are evident in the data and are now taken into account at next-to-leading order in QCD perturbation theory. The strong-coupling ratios {alpha}{sub s}{sup b}/{alpha}{sub s}{sup uds} and {alpha}{sub s}{sup c}/{alpha}{sub s}{sup uds} are found to be consistent with unity. Determinations of the b-quark mass m{sub b} (M{sub Z}) are discussed.

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

International Nuclear Information System (INIS)

Meyer, Harvey B

2011-01-01

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 ∼20% 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-per cent level. We estimate how much additional contribution from the ω∼ c .

Non-perturbative RPA-method implemented in the Coulomb gauge QCD Hamiltonian: From quarks and gluons to baryons and mesons

Science.gov (United States)

Yepez-Martinez, Tochtli; Civitarese, Osvaldo; Hess, Peter O.

2018-02-01

Starting from an algebraic model based on the QCD-Hamiltonian and previously applied to study meson states, we have developed an extension of it in order to explore the structure of baryon states. In developing our approach we have adapted concepts taken from group theory and non-perturbative many-body methods to describe states built from effective quarks and anti-quarks degrees of freedom. As a Hamiltonian we have used the QCD Hamiltonian written in the Coulomb Gauge, and expressed it in terms of effective quark-antiquark, di-quarks and di-antiquark excitations. To gain some insights about the relevant interactions of quarks in hadronic states, the Hamiltonian was approximately diagonalized by mapping quark-antiquark pairs and di-quarks (di-antiquarks) onto phonon states. In dealing with the structure of the vacuum of the theory, color-scalar and color-vector states are introduced to account for ground-state correlations. While the use of a purely color-scalar ground state is an obvious choice, so that colorless hadrons contain at least three quarks, the presence of coupled color-vector pairs in the ground state allows for colorless excitations resulting from the action of color objects upon it.

Dibaryon states containing two different types of heavy quarks

International Nuclear Information System (INIS)

Leandri, J.; Silvestre-Brac, B.

1995-01-01

In a recent series of papers we have shown that including heavy quarks in the dibaryon sector can lead to configurations stable against decay into two baryons. In this study we extend our previous work by a study of all the physical Q 2 q 4 [Q denotes a heavy quark and q denotes a member of the SU(3) F triplet representation] systems in a solvable chromomagnetic model. We propose a number of new heavy states which could be stable under strong interactions

Non-perturbative aspects of quantum field theory. From the quark-gluon plasma to quantum gravity

International Nuclear Information System (INIS)

Christiansen, Nicolai

2015-01-01

In this dissertation we investigate several aspects of non-perturbative quantum field theory. Two main parts of the thesis are concerned with non-perturbative renormalization of quantum gravity within the asymptotic safety scenario. This framework is based on a non-Gaussian ultraviolet fixed point and provides a well-defined theory of quantized gravity. We employ functional renormalization group (FRG) techniques that allow for the study of quantum fields even in strongly coupled regimes. We construct a setup for the computation of graviton correlation functions and analyze the ultraviolet completion of quantum gravity in terms of the properties of the two- and three point function of the graviton. Moreover, the coupling of gravity to Yang-Mills theories is discussed. In particular, we study the effects of graviton induced interactions on asymptotic freedom on the one hand, and the role of gluonic fluctuations in the gravity sector on the other hand. The last subject of this thesis is the physics of the quark-gluon plasma. We set-up a general non-perturbative strategy for the computation of transport coefficients in non-Abelian gauge theories. We determine the viscosity over entropy ratio η/s in SU(3) Yang-Mills theory as a function of temperature and estimate its behavior in full quantum chromodynamics (QCD).

Renormalized sum rules for structure functions of heavy meson decays

International Nuclear Information System (INIS)

Grozin, A.G.; Korchemsky, G.P.

1996-01-01

We consider the properties of the structure functions of inclusive heavy meson decays B→X c and treat the c quark mass as a free parameter. We show that in two extreme cases of heavy and light c quarks the structure functions of heavy-heavy and heavy-light transitions are given by a Fourier transform of the matrix elements of Wilson lines containing a timelike and a lightlike segment, correspondingly. Using the renormalization properties of Wilson lines we find the dependence of the structure functions on the factorization scale, the structure function of the heavy-heavy transition is renormalized multiplicatively, while that of the heavy-light transition obeys the GLAP-type evolution equation. We propose a generalization of the sum rules for the moments of the structure functions (Bjorken, Voloshin, and the open-quote open-quote third close-quote close-quote sum rules) with a soft exponential factorization cutoff, which correctly incorporates both perturbative and nonperturbative effects. We analyze nonperturbative corrections by first considering infrared renormalon contributions to the Wilson lines. Uncertainties induced by the leading renormalon pole at u=1/2 are exactly canceled by a similar uncertainty in the heavy quark pole mass. The leading nonperturbative corrections associated with the next renormalon at u=1 are parametrized by the matrix element μ π 2 which is proportional to the heavy quark kinetic energy. copyright 1996 The American Physical Society

Nonperturbative effects in B → Xsl+l- for large dilepton invariant mass

International Nuclear Information System (INIS)

Buchalla, G.

1998-01-01

The authors consider the calculation of O(Λ QCD 2 /m b 2 ) nonperturbative corrections to B → X s l + l - decay. The analysis confirms the results of Ali et al. for the dilepton invariant mass spectrum, which were in disagreement with an earlier publication, and for the lepton forward-backward asymmetry. The authors also give expressions for the O(Λ QCD 2 /m b 2 ) corrections to the left-right asymmetry. In addition the authors discuss the breakdown of the heavy quark expansion near the point of maximal dilepton invariant mass q 2 and consider a model independent approach to this region using heavy hadron chiral perturbation theory. The modes B → Kl + l - and B → Kπl + l - , which determine the endpoint region of the inclusive decay, are analysed within this framework. An interpolation is suggested between the region of moderately high q 2 , where the heavy quark expansion is still valid, and the vicinity of the endpoint described by chiral perturbation theory. The authors also comment on further nonperturbative effects in B → Kl + l -

HQET at order 1/m. Pt. 1. Non-perturbative parameters in the quenched approximation

International Nuclear Information System (INIS)

Blossier, Benoit; Della Morte, Michele; Garron, Nicolas; Edinburgh Univ.; Sommer, Rainer

2010-01-01

We determine non-perturbatively the parameters of the lattice HQET Lagrangian and those of heavy-light axial-vector and vector currents in the quenched approximation. The HQET expansion includes terms of order 1/m b . Our results allow to compute, for example, the heavy-light spectrum and B-meson decay constants in the static approximation and to order 1/m b in HQET. The determination of the parameters is separated into universal and non-universal parts. The universal results can be used to determine the parameters for various discretizations. The computation reported in this paper uses the plaquette gauge action and the ''HYP1/2'' action for the b-quark described by HQET. The parameters of the currents also depend on the light-quark action, for which we choose non-perturbatively O(a)-improved Wilson fermions. (orig.)

HQET at order 1/m. Pt. 1. Non-perturbative parameters in the quenched approximation

Energy Technology Data Exchange (ETDEWEB)

Blossier, Benoit [Paris XI Univ., 91 - Orsay (France). Lab. de Physique Theorique; Della Morte, Michele [Mainz Univ. (Germany). Inst. fuer Kernphysik; Garron, Nicolas [Universidad Autonoma de Madrid (Spain). Dept. Fisica Teorica y Inst. de Fisica Teorica UAM/CSIC; Edinburgh Univ. (United Kingdom). School of Physics and Astronomy - SUPA; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

2010-01-15

We determine non-perturbatively the parameters of the lattice HQET Lagrangian and those of heavy-light axial-vector and vector currents in the quenched approximation. The HQET expansion includes terms of order 1/m{sub b}. Our results allow to compute, for example, the heavy-light spectrum and B-meson decay constants in the static approximation and to order 1/m{sub b} in HQET. The determination of the parameters is separated into universal and non-universal parts. The universal results can be used to determine the parameters for various discretizations. The computation reported in this paper uses the plaquette gauge action and the ''HYP1/2'' action for the b-quark described by HQET. The parameters of the currents also depend on the light-quark action, for which we choose non-perturbatively O(a)-improved Wilson fermions. (orig.)

Heavy-heavy-light quark potential in SU(3) lattice QCD

International Nuclear Information System (INIS)

Yamamoto, Arata; Suganuma, Hideo; Iida, Hideaki

2008-01-01

We perform the first study for the heavy-heavy-light quark (QQq) potential in SU(3) quenched lattice QCD with the Coulomb gauge. The calculations are done with the standard gauge and O(a)-improved Wilson fermion action on the 16 4 lattice at β=6.0. We calculate the energy of QQq systems as the function of the distance R between the two heavy quarks, and find that the QQq potential is well described with a Coulomb plus linear potential form up to the intermediate distance R≤0.8 fm. Compared to the static three-quark case, the effective string tension between the heavy quarks is significantly reduced by the finite-mass valence quark effect. This reduction is considered to be a general property for baryons

Heavy quark production form jet conversions in a quark-gluon plasma

Energy Technology Data Exchange (ETDEWEB)

Liu , W.; Fries, R.

2008-05-22

Recently, it has been demonstrated that the chemical composition of jets in heavy ion collisions is significantly altered compared to the jets in the vacuum. This signal can be used to probe the medium formed in nuclear collisions. In this study we investigate the possibility that fast light quarks and gluons can convert to heavy quarks when passing through a quark-gluon plasma. We study the rate of light to heavy jet conversions in a consistent Fokker-Planck framework and investigate their impact on the production of high-p{sub T} charm and bottom quarks at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Higgs boson mass bounds in the presence of a heavy fourth quark family

Energy Technology Data Exchange (ETDEWEB)

Bulava, John [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Gerhold, Philipp; Kallarackal, Jim; Nagy, Attila [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

2013-01-15

We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.

Higgs boson mass bounds in the presence of a heavy fourth quark family

CERN Document Server

Bulava, John; Nagy, Attila; Kallarackal, Jim; Jansen, Karl

2012-01-01

We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.

Heavy quark energy loss in nuclear medium

International Nuclear Information System (INIS)

Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian

2003-01-01

Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark

Phenomenology of heavy quark systems

International Nuclear Information System (INIS)

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

Probing the Quark Gluon Plasma with Heavy Flavours: recent results from ALICE

CERN Multimedia

CERN. Geneva

2017-01-01

The study of open heavy-flavour physics allows us to investigate the key properties of the Quark-Gluon Plasma (QGP) and the microscopic processes ongoing in the medium produced in heavy-ion collisions at relativistic energies. Heavy quarks are produced in the early stages of heavy-ion collisions and their further production and annihilation rates in the medium are expected to be very small throughout the evolution of the system. Therefore, they serve as penetrating probes that traverse the hot and dense medium, interact with the partonic constituents of the plasma and lose energy. Understanding the interactions of heavy quarks with the medium requires precise measurements over a wide momentum range in heavy-ion collisions, but also in smaller systems like pp collisions, which also test next-to-leading order perturbative QCD calculations, and proton-nucleus collisions, which are sensitive to Cold Nuclear Matter effects (CNM), such as the modification of the parton distribution functions of nuclei, and parton ...

New theoretical results in heavy quark hadroproduction

International Nuclear Information System (INIS)

Nason, P.

1992-01-01

We describe the status of the heavy quark hadroproduction theory. In particular, we discuss recent developments on production of heavy quarks in the high energy limit, and the results of a new calculation to next-to-leading accuracy of the fully exclusive parton cross section for heavy quark production. (orig.)

Non-perturbative Approach to Equation of State and Collective Modes of the QGP

Directory of Open Access Journals (Sweden)

Y.F. Liu Shuai

2018-01-01

Full Text Available We discuss a non-perturbative T-matrix approach to investigate the microscopic structure of the quark-gluon plasma (QGP. Utilizing an effective Hamiltonian which includes both light- and heavy-parton degrees of freedoms. The basic two-body interaction includes color-Coulomb and confining contributions in all available color channels, and is constrained by lattice-QCD data for the heavy-quark free energy. The in-medium T-matrices and parton spectral functions are computed selfconsistently with full account of off-shell properties encoded in large scattering widths. We apply the T-matrices to calculate the equation of state (EoS for the QGP, including a ladder resummation of the Luttinger-Ward functional using a matrix-log technique to account for the dynamical formation of bound states. It turns out that the latter become the dominant degrees of freedom in the EoS at low QGP temperatures indicating a transition from parton to hadron degrees of freedom. The calculated spectral properties of one- and two-body states confirm this picture, where large parton scattering rates dissolve the parton quasiparticle structures while broad resonances start to form as the pseudocritical temperature is approached from above. Further calculations of transport coefficients reveal a small viscosity and heavy-quark diffusion coefficient.

Heavy quark effective theory and heavy baryon transitions

International Nuclear Information System (INIS)

Hussain, F.

1992-01-01

The heavy quark effective theory (HQET) is applied to study the weak decay of heavy mesons and heavy baryons and to predict the form factors for heavy to heavy and heavy to light transitions. 28 refs, 10 figs, 2 tabs

Heavy quark production and spectroscopy

International Nuclear Information System (INIS)

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

Perturbative study of the QCD phase diagram for heavy quarks at nonzero chemical potential: Two-loop corrections

Science.gov (United States)

Maelger, J.; Reinosa, U.; Serreau, J.

2018-04-01

We extend a previous investigation [U. Reinosa et al., Phys. Rev. D 92, 025021 (2015), 10.1103/PhysRevD.92.025021] of the QCD phase diagram with heavy quarks in the context of background field methods by including the two-loop corrections to the background field effective potential. The nonperturbative dynamics in the pure-gauge sector is modeled by a phenomenological gluon mass term in the Landau-DeWitt gauge-fixed action, which results in an improved perturbative expansion. We investigate the phase diagram at nonzero temperature and (real or imaginary) chemical potential. Two-loop corrections yield an improved agreement with lattice data as compared to the leading-order results. We also compare with the results of nonperturbative continuum approaches. We further study the equation of state as well as the thermodynamic stability of the system at two-loop order. Finally, using simple thermodynamic arguments, we show that the behavior of the Polyakov loops as functions of the chemical potential complies with their interpretation in terms of quark and antiquark free energies.

Detecting heavy quarks

International Nuclear Information System (INIS)

Benenson, G.; Chau, L.L.; Ludlam, T.; Paige, F.E.; Platner, E.D.; Protopopescu, S.D.; Rehak, P.

1983-01-01

In this exercise we examine the performance of a detector specifically configured to tag heavy quark (HQ) jets through direct observations of D-meson decays with a high resolution vertex detector. To optimize the performance of such a detector, we assume the small diamond beam crossing configuration as described in the 1978 ISABELLE proposal, giving a luminosity of 10 32 cm -2 sec -1 . Because of the very large backgrounds from light quark (LQ) jets, most triggering schemes at this luminosity require high P/sub perpendicular to/ leptons and inevitably give missing neutrinos. If alternative triggering schemes could be found, then one can hope to find and calculate the mass of objects decaying to heavy quarks. A scheme using the high resolution detector will also be discussed in detail. The study was carried out with events generated by the ISAJET Monte Carlo and a computer simulation of the described detector system

Investigation of doubly heavy baryon production at e+e- colliders

International Nuclear Information System (INIS)

Ma, J.P.; Si, Z.G.

2004-01-01

In this talk, we investigate the doubly heavy baryon production by factorizing nonperturbative- and perturbative effects: A pair of heavy quarks can be produced perturbatively and then the pair is transformed into the baryon. The transformation is nonperturbative. Since a heavy quark moves with a small velocity in the baryon in its rest frame, NRQCD can be used to describe the transformation. At the leading order, the baryon is found to be formed from two states of the heavy-quark pair, one state is with the pair in 3 S 1 state and in color 3-bar, another is with the pair in 1 S 0 state and in color 6. Two matrix elements are defined for the transformation from the two states, and their perturbative coefficients in the contribution to the cross-section at a e + e - collider are calculated. (author)

Quark-quark interactions

International Nuclear Information System (INIS)

Jacob, M.

1982-01-01

This chapter discusses interactions only at the constituent level, as observed in hadron-hadron collisions. It defines quarks and gluons as constituents of the colliding hadrons, reviews some applications of perturbative OCD, discussing in turn lepton pair production, which in lowest order approximation corresponds to the Drell-Yan process. It investigates whether quark-quark interactions could not lead to some new color structure different from those prevalent for known baryons and mesons, which could be created in hadron interactions, and whether color objects (not specifically quarks or gluons) could not appear as free particles. Discussed is perturbative QCD in hadron collisions; the quark approach to soft processes; and new color structures. It points out that perturbative QCD has been at the origin of much progress in the understanding of hadron interactions at the constituent level

Back-to-back heavy quark pair production in semi-inclusive DIS

Science.gov (United States)

Zhang, Guang-Peng

2017-11-01

The one-loop correction to heavy quark pair back-to-back production in unpolarized semi-inclusive deep inelastic scattering is given in this work in the framework of transverse momentum dependent(TMD) factorization. Both unpolarized and linearly polarized TMD gluon distribution functions are taken into account. A subtraction method based on diagram expansion is used to get finite hard coefficients. It is found the soft and collinear divergences of one-loop amplitude is proportional to tree level ones and can be expressed through several basic scalar triangle and bubble integrals. The subtraction of these divergences is spin independent. Beyond tree level an additional soft factor related to final heavy quark pair must be added into the factorization formula. This soft factor affects the azimuthal angle distribution of virtual photon in a nonperturbative way. Integrating over virtual photon azimuthal angle we construct three weighted cross sections, which depend on only three additional integrated soft factors. These weighted cross sections can be used to extract linearly polarized gluon distribution function. In addition, lepton azimuthal angle is unintegrated in this work, which provides more observables. All hard coefficients relevant to lepton and virtual photon azimuthal angle distributions are given at one-loop level.

Heavy quarks

International Nuclear Information System (INIS)

Khoze, V.A.

1983-10-01

We discuss the results accumulated during the last five years in heavy quark physics and try to draw a simple general picture of the present situation. The survey is based on a unified point of view resulting from quantum chromodynamics. (orig.)

Spin degeneracy of Hadronic molecules in the heavy quark region

Science.gov (United States)

Yamaguchi, Yasuhiro

2018-03-01

Hadronic molecules have been considered to appear close to the hadron-hadron threshold. For the heavy mesons, \\bar D and B, the one pion exchange potential is enhanced by the mass degeneracy of heavy pseudoscalar and vector mesons, caused by the heavy quark spin symmetry. In this study, we investigate new hadronic molecules formed by the heavy meson {P≤ft( * \\right)} = {\\bar D≤ft( * \\right)},{B≤ft( * \\right)} and a nucleon N, being P (*) N. As the interaction between P (*) and N, the pion and vector meson (ρ and ω) exchanges are considered. By solving the coupled-channel Schrödinger equations for P N and P*N, we obtain the bound and resonant states in the charm and bottom sectors, and in the in nite heavy quark mass limit. In the molecular states, the PN - P*N mixing effect is important, where the tensor force of the one pion exchange potential generates the strong attraction. In the heavy quark limit, we obtain the degeneracy of the states for J P = 1/2- and 3/2-.

Formation of heavy quarks in ultrarelativistic heavy-ion collisions

International Nuclear Information System (INIS)

Schneider, S.M.; Greiner, W.; Soff, G.

1992-02-01

We investigate the production of heavy quarks in continuum and bound states in nuclear collisions. Creation for free banti b and tanti t quark pairs and for bottomonium and toponium in the ground state are computed at RHIC, LHC and SSC energies. Central and peripheral heavy-ion collisions are discussed. For top quark creation we assumed a mass range of 90 GeV ≤ m t ≤ 250 GeV. The creation rate for top quarks on peripheral collisions is estimated to be by a factor 40 to 130 smaller compared with corresponding central collisions. For m t = 130 GeV we calculated a creation rate of about 4760 top quark pairs per day at the LHC (3.5 TeV/u) for Pb-Pb collisions. (orig.)

A search for quarks produced in heavy-ion interactions

CERN Multimedia

2002-01-01

We propose to search for free fractional charges produced in 225~GeV/A heavy-ion collisions at the SPS. A tank of mercury placed in the NA38 beam stop will serve both as a production target and as an absorber to stop reaction products. Mercury from the tank will subsequently be distilled.\\\\ \\\\ This process will decrease the amount of mercury that has to be processed by a factor of about $10^{5}$. The concentrate will be searched for quarks using the proven SFSU automated Millikan apparatus.\\\\ \\\\ This experiment will be sensitive to about one quark produced per $2 \\times 10^{8}$ beam particles.

Nonperturbative QCD simulations with 2+1 flavors of improved staggered quarks

International Nuclear Information System (INIS)

Bazavov, A.; Toussaint, D.; Bernard, C.; Laiho, J.; DeTar, C.; Levkova, L.; Oktay, M. B.; Gottlieb, Steven; Heller, U. M.; Hetrick, J. E.; Mackenzie, P. B.; Sugar, R.; Van de Water, R. S.

2010-01-01

Dramatic progress has been made over the last decade in the numerical study of quantum chromodynamics (QCD) through the use of improved formulations of QCD on the lattice (improved actions), the development of new algorithms, and the rapid increase in computing power available to lattice gauge theorists. In this article simulations of full QCD are described using the improved staggered quark formalism, ''asqtad'' fermions. These simulations were carried out with two degenerate flavors of light quarks (up and down) and with one heavier flavor, the strange quark. Several light quark masses, down to about three times the physical light quark mass, and six lattice spacings have been used. These enable controlled continuum and chiral extrapolations of many low energy QCD observables. The improved staggered formalism is reviewed, emphasizing both advantages and drawbacks. In particular, the procedure for removing unwanted staggered species in the continuum limit is reviewed. Then the asqtad lattice ensembles created by the MILC Collaboration are described. All MILC lattice ensembles are publicly available, and they have been used extensively by a number of lattice gauge theory groups. The physics results obtained with them are reviewed, and the impact of these results on phenomenology is discussed. Topics include the heavy quark potential, spectrum of light hadrons, quark masses, decay constants of light and heavy-light pseudoscalar mesons, semileptonic form factors, nucleon structure, scattering lengths, and more.

Quark-gluon plasma: Status of heavy ion physics

Indian Academy of Sciences (India)

Lattice quantum chromodynamics (QCD), defined on a discrete space–time lattice, leads to a spectacular non-perturbative prediction of a new state of matter, called quark-gluon plasma (QGP), at sufficiently high temperatures or equivalently large energy densities. The experimental programs of CERN, Geneva and BNL, ...

Electromagnetic properties of light and heavy baryons in the relativistic quark model

International Nuclear Information System (INIS)

Nicmorus Marinescu, Diana

2007-01-01

One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the investigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electromagnetic form factors of the N→Δγ transition are successfully reproduced. The relativistic quark model can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a composite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invariance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the compositeness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are unambiguously determined from the best fit to the data. The heavy quark limit within this

Electromagnetic properties of light and heavy baryons in the relativistic quark model

Energy Technology Data Exchange (ETDEWEB)

Nicmorus Marinescu, Diana

2007-06-14

One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the investigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electromagnetic form factors of the N{yields}{delta}{gamma} transition are successfully reproduced. The relativistic quark model can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a composite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invariance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the compositeness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are unambiguously determined from the best fit to the data. The heavy quark limit

Chemical Evolution of Strongly Interacting Quark-Gluon Plasma

International Nuclear Information System (INIS)

Pan, Ying-Hua; Zhang, Wei-Ning

2014-01-01

At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations

Non-perturbative effective interactions in the standard model

Energy Technology Data Exchange (ETDEWEB)

Arbuzov, Boris A. [Moscow Lomonosov State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics

2014-07-01

This monograph is devoted to the nonperturbative dynamics in the Standard Model (SM), the basic theory of allfundamental interactions in natureexcept gravity. The Standard Model is divided into two parts: the quantum chromodynamics (QCD) and the electro-weak theory (EWT) are well-defined renormalizable theories in which the perturbation theory is valid. However, for the adequate description of the real physics nonperturbative effects are inevitable. This book describes how these nonperturbative effects may be obtained in the framework of spontaneous generation of effective interactions. The well-known example of such effective interaction is provided by the famous Nambu-Jona-Lasinio effective interaction. Also a spontaneous generation of this interaction in the framework of QCD is described and applied to the method for other effective interactions in QCD and EWT. The method is based on N.N. Bogolyubov's conception of compensation equations. As a result we then describe the principal features of the Standard Model, e.g. Higgs sector, and significant nonperturbative effects including recent results obtained at LHC and TEVATRON.

Weak decays of heavy quarks

International Nuclear Information System (INIS)

Gaillard, M.K.

1978-08-01

The properties that may help to identify the two additional quark flavors that are expected to be discovered. These properties are lifetime, branching ratios, selection rules, and lepton decay spectra. It is also noted that CP violation may manifest itself more strongly in heavy particle decays than elsewhere providing a new probe of its origin. The theoretical progress in the understanding of nonleptonic transitions among lighter quarks, nonleptonic K and hyperon decay amplitudes, omega minus and charmed particle decay predictions, and lastly the Kobayashi--Maskawa model for the weak coupling of heavy quarks together with the details of its implications for topology and bottomology are treated. 48 references

Heavy baryon transitions and the heavy quark effective theory

International Nuclear Information System (INIS)

Hussain, F.

1992-01-01

Heavy baryon decays are studied in the context of the Bethe-Salpeter approach to the heavy quark effective theory. A drastic reduction, in the number of independent form factors, is found. Results are presented both for heavy to heavy and heavy to light baryon decays. (orig.)

Properties of Doubly Heavy Baryons in the Relativistic Quark Model

International Nuclear Information System (INIS)

Ebert, D.; Faustov, R.N.; Galkin, V.O.; Martynenko, A.P.

2005-01-01

Mass spectra and semileptonic decay rates of baryons consisting of two heavy (b or c) and one light quark are calculated in the framework of the relativistic quark model. The doubly heavy baryons are treated in the quark-diquark approximation. The ground and excited states of both the diquark and quark-diquark bound systems are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy-quark mass is used. The weak transition amplitudes of heavy diquarks bb and bc going, respectively, to bc and cc are explicitly expressed through the overlap integrals of the diquark wave functions in the whole accessible kinematic range. The relativistic baryon wave functions of the quark-diquark bound system are used for the calculation of the decay matrix elements, the Isgur-Wise function, and decay rates in the heavy-quark limit

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.)

Quark model and high energy collisions

CERN Document Server

Anisovich, V V; Nyíri, J; Shabelski, Yu M

2004-01-01

This is an updated version of the book published in 1985. QCD-motivated, it gives a detailed description of hadron structure and soft interactions in the additive quark model, where hadrons are regarded as composite systems of dressed quarks. In the past decade it has become clear that nonperturbative QCD, responsible for soft hadronic processes, may differ rather drastically from perturbative QCD. The understanding of nonperturbative QCD requires a detailed investigation of the experiments and the theoretical approaches. Bearing this in mind, the book has been rewritten paying special attenti

Heavy quark correlations in hadronic collisions

International Nuclear Information System (INIS)

Mangano, M.L.; Ridolfi, G.

1992-01-01

The study of heavy quark production at hadron colliders will provide important tests and measurements within and possibly beyond the Standard Model. The results of a recent calculation of heavy quark hadronic production correlation properties at the full next-to-leading order (NLO) in perturbative QCD are presented. These properties are important for several applications. (R.P.) 8 refs.; 3 figs

Heavy quark production processes in QCD

International Nuclear Information System (INIS)

Brodsky, S.J.; Gunion, J.F.

1984-12-01

We have identified two novel effects in QCD, each of which acts to enhance the production of heavy quark and supersymmetric particles beyond what is conventionally expected from gluon fusion. Both effects are present in QED, but are compounded in QCD because of the increased number of diagrams and the much larger coupling constant. The intrinsic charm quark distribution in the nucleon could account for the observed enhancements of the charm structure function at large x and features of the charm production data but this mechanism is relatively suppressed for heavier systems. Prebinding distortion of the fusion cross section is, however, likely to be significant for the production at low p/sub T/ of all particles containing heavy colored constituents. At this stage the QCD calculations are highly model dependent although they agree with the general properties which can be inferred from the operator product expansion in the heavy quark mass. Much more theoretical analysis of these effects is clearly needed. It is also clear that much more experimental work is necessary to extend and confirm the reported anomalous heavy quark signals. 22 references

Nonperturbative aspects of the quark-photon vertex

International Nuclear Information System (INIS)

Frank, M.R.

1994-01-01

The electromagnetic interaction with quarks is investigated through a relativistic, electromagnetic gauge-invariant treatment. Gluon dressing of the quark-photon vertex and the quark self-energy functions is described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger-Dyson equation in the rainbow approximation respectively. Results for the calculation of the quark-photon vertex are presented in both the time-like and space-like regions of photon momentum squared, however emphasis is placed on the space-like region relevant to electron scattering. The treatment presented here simultaneously addresses the role of dynamically generated q bar q vector bound states and the approach to asymptotic behavior. The resulting description is therefore applicable over the entire range of momentum transfers available in electron scattering experiments. Input parameters are limited to the model gluon two-point function which is chosen to reflect confinement and asymptotic freedom and are largely constrained by the obtained bound-state spectrum

Integrability in heavy quark effective theory

Science.gov (United States)

Braun, Vladimir M.; Ji, Yao; Manashov, Alexander N.

2018-06-01

It was found that renormalization group equations in the heavy-quark effective theory (HQET) for the operators involving one effective heavy quark and light degrees of freedom are completely integrable in some cases and are related to spin chain models with the Hamiltonian commuting with the nondiagonal entry C( u) of the monodromy matrix. In this work we provide a more complete mathematical treatment of such spin chains in the QISM framework. We also discuss the relation of integrable models that appear in the HQET context with the large-spin limit of integrable models in QCD with light quarks. We find that the conserved charges and the "ground state" wave functions in HQET models can be obtained from the light-quark counterparts in a certain scaling limit.

Hyperon-nucleon interaction in the quark cluster model

International Nuclear Information System (INIS)

Straub, U.; Zhang Zongye; Braeuer, K.; Faessler, A.; Khadkikar, S.B.; Luebeck, G.

1988-01-01

The lambda-nucleon and sigma-nucleon interaction is described in the nonrelativistic quark cluster model. The SU(3) flavor symmetry breaking due to the different quark masses is taken into account, i.e. different wavefunctions for the light (up, down) and heavy (strange) quarks are used in flavor and orbital space. The six-quark wavefunction is fully antisymmetrized. The model hamiltonian contains gluon exchange, pseudoscalar meson exchange and a phenomenological σ-meson exchange. The six-quark scattering problem is solved within the resonating group method. The experimental lambda-nucleon and sigma-nucleon cross sections are well reproduced. (orig.)

Properties of bound states containing fourth family quarks

International Nuclear Information System (INIS)

Bashiry, V; Azizi, K; Sultansoy, S

2012-01-01

The heavy fourth generation of quarks that have sufficiently small mixing with the three known SM families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from fourth family and the other from observed SM quarks, namely charm or bottom quark, in the framework of the QCD sum rules. In the calculations, the two gluon condensate diagrams as nonperturbative contributions are taken into account. The obtained numerical results are reduced to the known masses and decay constants of the b-bar b and c-bar c quarkonia, when the fourth family quark is replaced by the bottom or charm quark.

Lattice calculation of heavy-light decay constants with two flavors of dynamical quarks

International Nuclear Information System (INIS)

Bernard, C.; Datta, S.; DeGrand, T.; DeTar, C.; Gottlieb, Steven; Heller, Urs M.; McNeile, C.; Orginos, K.; Sugar, R.; Toussaint, D.

2002-01-01

We present results for f B , f B s , f D , f D s and their ratios in the presence of two flavors of light sea quarks (N f =2). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonperturbatively improved clover fermions allow us to improve our control of the continuum extrapolation. For our central values the masses of the sea quarks are not extrapolated to the physical u, d masses; that is, the central values are ''partially quenched.'' A calculation using 'fat-link clover' valence fermions is also discussed but is not included in our final results. We find, for example, f B =190(7)( -17 +24 )( -2 +11 )( -0 +8 ) MeV, f B s /f B =1.16(1)(2)(2)( -0 +4 ), f D s =241(5)( -26 +27 )( -4 +9 )( -0 +5 ) MeV, and f B /f D s =0.79(2)( -4 +5 )(3)( -0 +5 ), where in each case the first error is statistical and the remaining three are systematic: the error within the partially quenched N f =2 approximation, the error due to the missing strange sea quark and to partial quenching, and an estimate of the effects of chiral logarithms at small quark mass. The last error, though quite significant in decay constant ratios, appears to be smaller than has been recently suggested by Kronfeld and Ryan, and Yamada. We emphasize, however, that as in other lattice computations to date, the lattice u,d quark masses are not very light and chiral log effects may not be fully under control

Vectorlike interactions of leptons and quarks

International Nuclear Information System (INIS)

Fritzsch, H.

1976-07-01

A vectorlike theory of hadronic weak interactions can only be constructed if there exist more than 4 quark flavours and more than 4 leptons. Any vectorlike theory implies the existence of right-handed weak currents. Typically those currents are relevant for the weak interactions of heavy leptons. The experimental consequences of some typical vectorlike models are discussed. (BJ) [de

Non-perturbative effective interactions in the standard model

CERN Document Server

Arbuzov, Boris A

2014-01-01

This monograph is devoted to the nonperturbative dynamics in the Standard Model (SM), the basic theory of all, but gravity, fundamental interactions in nature. The Standard Model is devided into two parts: the Quantum chromodynamics (QCD) and the Electro-weak theory (EWT) are well-defined renormalizable theories in which the perturbation theory is valid. However, for the adequate description of the real physics nonperturbative effects are inevitable. This book describes how these nonperturbative effects may be obtained in the framework of spontaneous generation of effective interactions. The well-known example of such effective interaction is provided by the famous Nambu--Jona-Lasinio effective interaction. Also a spontaneous generation of this interaction in the framework of QCD is described and applied to the method for other effective interactions in QCD and EWT. The method is based on N.N. Bogoliubov conception of compensation equations. As a result we then describe the principle feathures of the Standard...

Heavy-quark correlations in photon-hadron collisions

International Nuclear Information System (INIS)

Frixione, S.; Mangano, M.L.; Nason, P.; Ridolfi, G.

1994-01-01

We describe a next-to-leading-order calculation of the fully exclusive parton cross section at next-to-leading order for the photoproduction of heavy quarks. We use our result to compute quantities of interest for current fixed-target experiments. We discuss heavy-quark total cross sections, distributions, and correlations. (orig.)

Heavy quark effective theory computation of the mass of the bottom quark

International Nuclear Information System (INIS)

Della Morte, M.; Papinutto, M.

2006-10-01

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 s meson in HQET. All steps include the terms of order Λ 2 /m b . We discuss the computation and renormalization of correlation functions at order 1/m b . With the strange quark mass fixed from the Kaon mass and the QCD scale set through r 0 =0.5 fm, we obtain a renormalization group invariant mass M b =6.758(86) GeV or anti m b (anti m b )=4.347(48) GeV in the MS scheme. The uncertainty in the computed Λ 2 /m b terms contributes little to the total error and Λ 3 /m 2 b terms are negligible. The strategy is promising for full QCD as well as for other B-physics observables. (orig.)

Symmetry Relations and the Nonperturbative Form of Interactions

Institute of Scientific and Technical Information of China (English)

2001-01-01

Applying QCD to study and understand hadronic physics and nuclear physics is one of basic goals of modern nuclear physics. Developing nonperturbative approach of QCD to understand the dynamical chiral-symmetry breaking and color confinement then becomes one of our most important challenges. Besides the lattice gauge theory, the Dyson-Schwinger equation (DSE) formalism is such an appropriate nonperturbative approach. In undertaking nonperturbative studies using DSEs, we immediately have to confront the issue of what is the nonperturbative form of interactions. In recent 20 years, there have been considerable efforts to solve this open problem, however, all such attempts

Heavy mesons in the bootstrap quark model

International Nuclear Information System (INIS)

Gerasyuta, S.M.; Sarantsev, A.V.

1990-01-01

In the frame of an approach developed for light quarks the scattering amplitudes of heavy quarks qQ-bar→qQ-bar→,QQ-bar→QQ-bar (q=u,d,s; Q=c,b,t) are calculated. The obtained mass values of the lowest c,b-mesons multiplets (J P =0 - ,1 - ,0 + ) are in a good agreement with the experimental ones. The masses of the new heavy particles with the t-quark are predicted. 46 refs.; 4 figs.; 5 tabs

Exclusive description of multiple production on nuclei in the additive quark model. Multiplicity distributions in interactions with heavy nuclei

International Nuclear Information System (INIS)

Levchenko, B.B.; Nikolaev, N.N.

1985-01-01

In the framework of the additive quark model of multiple production on nuclei we calculate the multiplicity distributions of secondary particles and the correlations between secondary particles in πA and pA interactions with heavy nuclei. We show that intranuclear cascades are responsible for up to 50% of the nuclear increase of the multiplicity of fast particles. We analyze the sensitivity of the multiplicities and their correlations to the choice of the quark-hadronization function. We show that with good accuracy the yield of relativistic secondary particles from heavy and intermediate nuclei depends only on the number N/sub p/ of protons knocked out of the nucleus, and not on the mass number of the nucleus (N/sub p/ scaling)

Towards the dynamical study of heavy-flavor quarks in the Quark-Gluon-Plasma

International Nuclear Information System (INIS)

Berrehrah, H; Bratkovskaya, E; Cassing, W; Gossiaux, P B; Aichelin, J

2014-01-01

Within the aim of a dynamical study of on- and off-shell heavy quarks Q in the quark gluon plasma (QGP) – as produced in relativistic nucleus-nucleus collisions – we study the heavy quark collisional scattering on partons of the QGP. The elastic cross sections σ q,g−Q are evaluated for perturbative partons (massless on-shell particles) and for dynamical quasi-particles (massive off-shell particles as described by the dynamical quasi-particles model D QPM ) using the leading order Born diagrams. We demonstrate that the finite width of the quasi-particles in the DQPM has little influence on the cross sections σ q,g−Q except close to thresholds. We, furthermore, calculate the heavy quark relaxation time as a function of temperature T within the different approaches using these cross sections

Search for the Anomalous Interactions of Up-Type Heavy Quarks in γγ Collision at the LHC

International Nuclear Information System (INIS)

Köksal, M.; İnan, S. C.

2014-01-01

We investigate the anomalous interactions of heavy up-type quark t ′ in a γγ collision at the LHC. We have obtained 95% confidence level (CL) limit of t ′ qγ (q=u,c) anomalous coupling by taking into account three forward detector acceptances: 0.0015<ξ<0.15, 0.0015<ξ<0.5, and 0.1<ξ<0.5

Decoupling of heavy quarks in quantum chromodynamics

International Nuclear Information System (INIS)

Bernreuther, W.

1983-01-01

Decoupling of heavy quarks in quantum chromodynamics (QCD) defined by mass-independent renormalization is investigated. The structure of the relations between the parameters of f flavour QCD below a heavy-quark threshold is discussed to all orders in the loop expansion, and the relations are computed to two-loop approximation for the minimal subtraction schemes (MS) and to one-loop approximation for some Weinberg schemes. These matching relations can be used to systematically determine the renormalization group (RG)-invariant parameters of the effective theory in terms of the RG-invariant parameters of the theory which includes the heavy quark, or vice versa. For MS scheme the connection between Λ/sub f/-1 and Λ/sub f/ to two and three loops is given as well as the two-loop connection between the RG-invariant mass parameters of the f-1 and f flavour theory. The effect of heavy quarks on the evolution of the QCQ coupling is of significance for present QCD phenomenology based on next-to-leading-order perturbation theory. This is illustrated with a few examples within the MS scheme

Diquark structure in heavy quark baryons in a geometric model

International Nuclear Information System (INIS)

Paria, Lina; Abbas, Afsar

1996-01-01

Using a geometric model to study the structure of hadrons, baryons having one, two and three heavy quarks have been studied here. The study reveals diquark structure in baryons with one and two heavy quarks but not with three heavy identical quarks. (author). 15 refs., 2 figs., 2 tabs

Heavy quark effective theory and study of heavy hadron spectra

International Nuclear Information System (INIS)

Dong Yubing

1995-01-01

By employing the heavy quark effective theory, the spectra of heavy hadrons, such as heavy mesons (Q-barq), heavy baryons (QQq and Qqq) and heavy multiquark systems (Q-barQ-barqq) are studied systemically. The results are compared with the predictions for Q-barQ-barqq in potential model

World-Line Formalism: Non-Perturbative Applications

Directory of Open Access Journals (Sweden)

Dmitry Antonov

2016-11-01

Full Text Available This review addresses the impact on various physical observables which is produced by confinement of virtual quarks and gluons at the level of the one-loop QCD diagrams. These observables include the quark condensate for various heavy flavors, the Yang-Mills running coupling with an infra-red stable fixed point, and the correlation lengths of the stochastic Yang-Mills fields. Other non-perturbative applications of the world-line formalism presented in the review are devoted to the determination of the electroweak phase-transition critical temperature, to the derivation of a semi-classical analogue of the relation between the chiral and the gluon QCD condensates, and to the calculation of the free energy of the gluon plasma in the high-temperature limit. As a complementary result, we demonstrate Casimir scaling of k-string tensions in the Gaussian ensemble of the stochastic Yang-Mills fields.

Electron-muon correlation as a new probe of strongly interacting quark-gluon plasma

International Nuclear Information System (INIS)

Akamatsu, Yukinao; Hatsuda, Tetsuo; Hirano, Tetsufumi

2009-01-01

As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon that originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot plasma, we show that substantial quenching of the away-side peak in the electron-muon correlation can be seen if the sQGP drag force acting on heavy quarks is large enough as suggested from the gauge/gravity correspondence. The effect could be detected in high-energy heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

Definition of mass spectrum of mesons taking into account relativistic character of interactions

International Nuclear Information System (INIS)

Dinejkhan, M.; Zhaugasheva, S.A.; Karimzhan, K.

2009-01-01

Taking into account relativistic and nonlocal character of interactions, the mass spectrum of the mesons consisting of the light-light and light-heavy quarks with orbital and radial excitations, is determined. Our result show that good agreement with the experimental data for the slope and the intercept of the Regge trajectory can be obtained, only taking into account the nonperturbative and the nonlocal character of interactions. Dependence of constituent mass of constituent particles on mass of a free state is certain. When quarks are light the difference of current and valent masses of quarks is greater than valent masses of quarks, and when quarks are heavy the difference of these masses is insignificant. One of alternative variants of the account of nonlocality is suggested for the definition of properties of hadrons at large distances. Dependence of constituent mass on the radius of confinement is studied

Cancellation of renormalon ambiguities in the heavy quark effective theory

International Nuclear Information System (INIS)

Neubert, M.; Sachrajda, C.T.

1995-01-01

Recently, it has been shown that the concept of the pole mass of a heavy quark becomes ambiguous beyond perturbation theory, because of the presence of infrared renormalons. We argue that the predictions of the heavy quark effective theory, whose construction is based on the pole mass, are free of such ambiguities. In the 1/m Q expansion of physical quantities, infrared and ultraviolet renormalons compensate each other between coefficient functions and matrix elements. We trace the appearance of these compensations for current-induced exclusive heavy-to-heavy and heavy-to-light transitions, and for inclusive decays of heavy hadrons. In particular, we show that the structure of the heavy quark expansion is not obscured by renormalons, and none of the predictions of the heavy quark effective theory are invalidated. ((orig.))

Heavy quarks photoproduction

International Nuclear Information System (INIS)

Cacciari, M.

1996-08-01

The state of the art of the theoretical calculations for heavy quarks photoproduction is reviewed. The full next-to-leading order calculation and two possible resummations, the high energy one for total cross sections and the large p T one for differential cross sections, are described. (orig.)

Heavy baryons in the heavy quark effective theory

International Nuclear Information System (INIS)

Koerner, J.G.; Thompson, G.

1991-10-01

We give a mini-review of recent results on current-induced transitions between heavy baryons (and between heavy and light baryons) in the light of the new spin and flavour symmetries of the Heavy Quark Effective Theory (HQET). We discuss the structure of the 1/m corrections to the heavy mass limit and outline a diagrammatic proof that there are no 0(1/m) correction to the Voloshin-Shifman normalization condition at zero recoil. (orig.)

Heavy-quark production in gluon fusion at two loops in QCD

International Nuclear Information System (INIS)

Czakon, M.

2007-07-01

We present the two-loop virtual QCD corrections to the production of heavy quarks in gluon fusion. The results are exact in the limit when all kinematical invariants are large compared to the mass of the heavy quark up to terms suppressed by powers of the heavy-quark mass. Our derivation uses a simple relation between massless and massive QCD scattering amplitudes as well as a direct calculation of the massive amplitude at two loops. The results presented here together with those obtained previously for quark-quark scattering form important parts of the next-to-next-to-leading order QCD corrections to heavy-quark production in hadron-hadron collisions. (orig.)

Multiple parton scattering in nuclei: heavy quark energy loss and modified fragmentation functions

International Nuclear Information System (INIS)

Zhang Benwei; Wang, Enke; Wang Xinnian

2005-01-01

Multiple scattering, induced radiative energy loss and modified fragmentation functions of a heavy quark in nuclear matter are studied within the framework of generalized factorization in perturbative QCD. Modified heavy quark fragmentation functions and energy loss are derived in detail with illustration of the mass dependencies of the Landau-Pomeranchuk-Migdal interference effects and heavy quark energy loss. Due to the quark mass dependence of the gluon formation time, the nuclear size dependencies of nuclear modification of the heavy quark fragmentation function and heavy quark energy loss are found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss of the heavy quark is also significantly suppressed due to limited cone of gluon radiation imposed by the mass. Medium modification of the heavy quark fragmentation functions is found to be limited to the large z region due to the form of heavy quark fragmentation functions in vacuum

Perspectives in hadron and quark dynamics

International Nuclear Information System (INIS)

Amsler, C.; Bressani, T.; Close, F.E.; De Sanctis, E.; Frois, B.; Kunne, F.; Laget, J.M.; von Harrach, D.; Metag, V.; Mulders, P.J.; Riska, D.O.

1997-01-01

In the past two decades, quantum chromodynamics (QCD) has emerged as the theory for the strong force with quarks and gluons as the building blocks of nuclear matter at large densities and high temperatures. One of the most exciting challenges for nuclear physics is the study of the non-perturbative regime of QCD. It is this regime which is relevant for understanding how the elementary fields of QCD - quarks and gluons - build up particles such as protons and neutrons. A basic theoretical difficulty is the non-existence of asymptotic, isolated, colored objects. This is a feature of the richness of the vacuum structure of QCD. Understanding the different QCD phases and the transitions among them is the challenge of the modern study of strong interactions. At low energy, chiral symmetry can be used to build aneffective theory of hadron interactions. At higher energies, the parton model uses non-perturbative quark and gluon distributions to describe hadronic scattering processes. (orig)

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.

Quark-gluon plasma in strong magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Kalaydzhyan, Tigran

2013-04-15

One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.

Quark-gluon plasma in strong magnetic fields

International Nuclear Information System (INIS)

Kalaydzhyan, Tigran

2013-04-01

One of the fundamental problems in subatomic physics is the determination of properties of matter at extreme temperatures, densities and electromagnetic fields. The modern ultrarelativistic heavy-ion experiments are able to study such states (the quark-gluon plasma) and indicate that the physics at extreme conditions differs drastically from what is known from the conventional observations. Also the theoretical methods developed mostly within the perturbative framework face various conceptual problems and need to be replaced by a nonperturbative approach. In this thesis we study the physics of the strongly-coupled quark-gluon plasma in external magnetic fields as well as general electromagnetic and topological properties of the QCD and QCD-like systems. We develop and apply various nonperturbative techniques, based on e.g. gauge-gravity correspondence, lattice QCD simulations, relativistic hydrodynamics and condensed-matter-inspired models.

Nonperturbative electromagnetic muon-pair production with capture in peripheral relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Wells, J.C.

1991-01-01

We discuss preliminary calculations of impact-parameter-dependent probabilities and cross sections for muon-pair production with capture of the negative muon into the K-shell of the target caused by the time-dependent electromagnetic fields generated in peripheral relativistic heavy-ion collisions. Our approach is nonperturbative in that we calculate probabilities by solving the time-dependent Dirac equation on a three-dimensional Cartesian lattice using the basis-spline collocation method. Use of the axial gauge for the electromagnetic potentials produces an interaction easier to implement on the lattice than the Lorentz gauge. 19 refs., 5 figs

B-physics from non-perturbatively renormalized HQET in two-flavour lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Bernardoni, Fabio; Simma, Hubert [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Blossier, Benoit; Gerardin, Antoine [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique; CNRS, Orsay (France); Bulava, John [CERN, Geneva (Switzerland). Physics Department; Della Morte, Michele; Hippel, Georg M. von [Mainz Univ. (Germany). Inst. fuer Kernphysik; Fritzsch, Patrick [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Garron, Nicolas [Trinity College, Dublin (Ireland). School of Mathematics; Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Collaboration: ALPHA Collaboration

2012-10-15

We report on the ALPHA Collaboration's lattice B-physics programme based on N{sub f}=2 O(a) improved Wilson fermions and HQET, including all NLO effects in the inverse heavy quark mass, as well as non-perturbative renormalization and matching, to fix the parameters of the effective theory. Our simulations in large physical volume cover 3 lattice spacings a {approx} (0.08-0.05) fm and pion masses down to 190 MeV to control continuum and chiral extrapolations. We present the status of results for the b-quark mass and the B{sub (s)}-meson decay constants, f{sub B} and f{sub B{sub s}}.

Analyzing the Anomalous Dipole Moment Type Couplings of Heavy Quarks with FCNC Interactions at the CLIC

International Nuclear Information System (INIS)

Senol, A.; Tasci, A. T.; Verep, C.

2014-01-01

We examine both anomalous magnetic and dipole moment type couplings of a heavy quark via its single production with subsequent dominant standard model decay modes at the compact linear collider (CLIC). The signal and background cross sections are analyzed for heavy quark masses 600 and 700 GeV. We make the analysis to delimitate these couplings as well as to find the attainable integrated luminosities for 3σ observation limit

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.)

The heavy top quark and supersymmetry

Energy Technology Data Exchange (ETDEWEB)

Hall, L.J. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

1997-01-01

Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

The heavy top quark and supersymmetry

International Nuclear Information System (INIS)

Hall, L.J.; Univ. of California, Berkeley, CA

1996-01-01

Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the standard model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the standard model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed

The heavy top quark and supersymmetry

International Nuclear Information System (INIS)

Hall, L.J.

1997-01-01

Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed

Heavy quark and quarkonium production at CERN LEP2. kT-factorization versus data

International Nuclear Information System (INIS)

Lipatov, A.V.; Zotov, N.P.

2005-02-01

We present calculations of heavy quark and quarkonium production at CERN LEP2 in the κ 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/ψ 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 κ T -factorization formalism. (orig.)

Perturbative and nonperturbative renormalization in lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Goeckeler, M. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Horsley, R. [University of Edinburgh (United Kingdom). School of Physics and Astronomy; Perlt, H. [Leipzig Univ. (DE). Institut fuer Theoretische Physik] (and others)

2010-03-15

We investigate the perturbative and nonperturbative renormalization of composite operators in lattice QCD restricting ourselves to operators that are bilinear in the quark fields (quark-antiquark operators). These include operators which are relevant to the calculation of moments of hadronic structure functions. The nonperturbative computations are based on Monte Carlo simulations with two flavors of clover fermions and utilize the Rome-Southampton method also known as the RI-MOM scheme. We compare the results of this approach with various estimates from lattice perturbation theory, in particular with recent two-loop calculations. (orig.)

Comparison of potential models through heavy quark effective theory

International Nuclear Information System (INIS)

Amundson, J.F.

1995-01-01

I calculate heavy-light decay constants in a nonrelativistic potential model. The resulting estimate of heavy quark symmetry breaking conflicts with similar estimates from lattice QCD. I show that a semirelativistic potential model eliminates the conflict. Using the results of heavy quark effective theory allows me to identify and compensate for shortcomings in the model calculations in addition to isolating the source of the differences in the two models. The results lead to a rule as to where the nonrelativistic quark model gives misleading predictions

Searches for new heavy quarks in ATLAS

CERN Document Server

Nikiforou, Nikiforos; The ATLAS collaboration

2018-01-01

A search for new heavy quarks focusing on recent vector-like quark searches with the ATLAS detector at the CERN Large Hadron Collider is presented. Two recent searches targeting the pair production of type vector-like quarks are described. The first search is sensitive to vector-like up-type quark (T ) decays to a t quark and either a Standard Model Higgs boson or a Z boson. The second search is primarily sensitive to T decays to W boson and a b quark. Additionally, the results can be interpreted for alternative VLQ decays.

An alternative approach to heavy quark bags

International Nuclear Information System (INIS)

Baacke, J.; Kasperidus, G.

1980-01-01

We discuss a formulation of quark bags where the quark wave function depends only on the relative coordinate and the bag boundary is fixed with respect to the center of mass of the quark system. For technical reasons we have to restrict ourselves to a heavy quark-antiquark system in an s-wave with spherical boundary. A phenomenological application to quarkonium states encourages further investigation of the approach. (orig.)

The influence of initial state fluctuations on heavy quark energy loss in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Cao, Shanshan; Bass, Steffen A; Huang, Yajing; Qin, Guang-You

2015-01-01

We study the effects of initial state fluctuations on the dynamical evolution of heavy quarks inside a quark–gluon plasma (QGP) created in relativistic heavy-ion collisions. The evolution of heavy quarks in QGP matter is described utilizing a modified Langevin equation that incorporates the contributions from both collisional and radiative energy loss. The spacetime evolution of the fireball medium is simulated with a (2 + 1)-dimensional viscous hydrodynamic model. We find that when the medium traversed by the heavy quark contains a fixed amount of energy, heavy quarks tend to lose more energy for greater fluctuations of the medium density. This may result in a larger suppression of heavy flavor observables in a fluctuating QGP matter than in a smooth one. The possibility of using hard probes to infer the information of initial states of heavy-ion collisions is discussed. (paper)

Study of heavy quark production with the Mark II at PEP

International Nuclear Information System (INIS)

Abrams, G.; Amidei, D.; Baden, A.

1983-10-01

The methods adopted by the Mark II collaboration to study heavy quark production at PEP are described. Two complementary techniques are used: D* tagging using the decay chain D* + . D 0 π + , D 0 → K - π + , and inclusive lepton tagging using the characteristic p/sub T/ distributions to distinguish contributions from b and c quarks. These techniques are used to derive information about heavy quark fragmentation and about the weak coupling of heavy quarks

Baryons in the heavy quark effective theory

International Nuclear Information System (INIS)

Mannel, T.; Roberts, W.; Ryzak, Z.

1990-08-01

We show how to incorporate baryons in the heavy quark effective theory. A convenient formalism is exhibited and applied to semileptonic weak decays of heavy baryons and to exclusive production of heavy baryons in e + e - annihilation. (orig.)

Nonperturbative effects in B {yields} X{sub s}l{sup +}l{sup -} for large dilepton invariant mass

Energy Technology Data Exchange (ETDEWEB)

Buchalla, G. [CERN, Geneva (Switzerland). Theory Division; Isidori, G. [INFN, Laboratori Nazionali di Frascati, Rome (Italy)

1998-01-01

The authors consider the calculation of O({Lambda}{sub QCD}{sup 2}/m{sub b}{sup 2}) nonperturbative corrections to B {yields} X{sub s}l{sup +}l{sup -} decay. The analysis confirms the results of Ali et al. for the dilepton invariant mass spectrum, which were in disagreement with an earlier publication, and for the lepton forward-backward asymmetry. The authors also give expressions for the O({Lambda}{sub QCD}{sup 2}/m{sub b}{sup 2}) corrections to the left-right asymmetry. In addition the authors discuss the breakdown of the heavy quark expansion near the point of maximal dilepton invariant mass q{sup 2} and consider a model independent approach to this region using heavy hadron chiral perturbation theory. The modes B {yields} Kl{sup +}l{sup -} and B {yields} K{pi}l{sup +}l{sup -}, which determine the endpoint region of the inclusive decay, are analysed within this framework. An interpolation is suggested between the region of moderately high q{sup 2}, where the heavy quark expansion is still valid, and the vicinity of the endpoint described by chiral perturbation theory. The authors also comment on further nonperturbative effects in B {yields} Kl{sup +}l{sup -} .

Scaling violation in the heavy quark fragmentation functian

International Nuclear Information System (INIS)

Avaliani, I.S.; Kartvelishvili, V.G.

1981-01-01

The scaling violation in the heavy quark fragmentation functions is analysed in the framework of the leading logarithmic approximation in QCD and it is shown, that the slaling violation effects are more essential for heavy quarks, than for light ones. These results indicate that the D-meson inclusive spectra measurement is a sensitive test for some standard assumptions [ru

Implications of a high-mass diphoton resonance for heavy quark searches

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Shankha; Barducci, Daniele; Bélanger, Geneviève; Delaunay, Cédric [LAPTh, Université Savoie Mont Blanc, CNRS B.P. 110,F-74941 Annecy-le-Vieux (France)

2016-11-25

Heavy vector-like quarks coupled to a scalar S will induce a coupling of this scalar to gluons and possibly (if electrically charged) photons. The decay of the heavy quark into Sq, with q being a Standard Model quark, provides, if kinematically allowed, new channels for heavy quark searches. Inspired by naturalness considerations, we consider the case of a vector-like partner of the top quark. For illustration, we show that a singlet partner can be searched for at the 13 TeV LHC through its decay into a scalar resonance in the 2γ+ℓ+X final states, especially if the diphoton branching ratio of the scalar S is further enhanced by the contribution of non coloured particles. We then show that conventional heavy quark searches are also sensitive to this new decay mode, when S decays hadronically, by slightly tightening the current selection cuts. Finally, we comment about the possibility of disentangling, by scrutinising appropriate kinematic distributions, heavy quark decays to St from other standard decay modes.

Heavy quark production in ep collisions at HERA

International Nuclear Information System (INIS)

Derrick, M.

1987-01-01

There are substantial production rates of heavy quarks from ep collisions at HERA. The center of mass energy of about 300 GeV is well above any b-quark threshold effects, and for b/bar b/ production, the cross section is estimated to be 3.3 nb per event, leading to rates approaching 10 6 b mesons per year. The rates for c/bar c/ production are about two orders of magnitude greater. Two major detectors are under construction and a program of heavy quark physics will start in 1990. 3 refs., 4 figs

Heavy quarks and squarks from W-gluon fusion

International Nuclear Information System (INIS)

Lindfors, J.

1986-05-01

We discuss Wg-fusion as a source of heavy quark and squark pairs at very high energy hadron colliders. Effective W approximation is used to calculate the cross-sections analytically in the forward scattering configuration; good agreement is obtained with exact numerical calculations. W-gluon fusion is found to be not nearly as important a production mechanism of heavy squarks as it is of heavy quarks. This is especially true when the mass-splitting within the SU(2) L doublet is small

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...

Polarized heavy baryon production in quark-diquark model considering two different scenarios

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); Delpasand, M. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of)

2017-09-15

At sufficiently large transverse momentum, the dominant production mechanism for heavy baryons is actually the fragmentation. In this work, we first study the direct fragmentation of a heavy quark into the unpolarized triply heavy baryons in the leading order of perturbative QCD. In a completely different approach, we also analyze the two-stage fragmentation of a heavy quark into a scalar diquark followed by the fragmentation of such a scalar diquark into a triply heavy baryon: quark-diquark model of baryons. The results of this model are in acceptable agreement with those obtained through a full perturbative regime. Relying on the quark-diquark model and considering two different scenarios we determine the spin-dependent fragmentation functions of polarized heavy baryons in such a way that a vector or a pseudoscalar heavy diquark is an intermediate particle between the initial heavy quark and the final state baryon. (orig.)

A T-matrix calculation for in-medium heavy-quark gluon scattering

International Nuclear Information System (INIS)

Huggins, K.; Rapp, R.

2012-01-01

The interactions of charm and bottom quarks in a quark-gluon plasma (QGP) are evaluated using a thermodynamic 2-body T-matrix. We specifically focus on heavy-quark (HQ) interactions with thermal gluons with an input potential motivated by lattice-QCD computations of the HQ free energy. The latter is implemented into a field-theoretic ansatz for color-Coulomb and (remnants of) confining interactions. This, in particular, enables to discuss corrections to the potential approach, specifically hard-thermal-loop corrections to the vertices, relativistic corrections deduced from pertinent Feynman diagrams, and a suitable projection on transverse thermal gluons. The resulting potentials are applied to compute scattering amplitudes in different color channels and utilized for a calculation of the corresponding HQ drag coefficient in the QGP. A factor of ∼2-3 enhancement over perturbative results is obtained, mainly driven by the resummation in the attractive color-channels.

Hadronic production of baryons containing two heavy quarks

International Nuclear Information System (INIS)

Berezhnoj, A.V.; Kiselev, V.V.; Likhoded, A.K.

1995-01-01

In the framework of the QCD perturbation theory, total and differential cross sections of the Ξ bc ' , Ξ bc ( * ) and Ξ cc ( * ) baryons production in gluon collisions are calculated in the leading order over α s for the doubly heavy (bc) and (cc) diquarks. At both small and large transverse momenta of baryons, a use of the mechanism of the heavy quark fragmentation into the heavy diquark is shown to underestimate the cross section values in comparison with the exact numerical calculations of a complete set of diagrams. The expected in Tevatron experiments yield of baryons with two heavy quarks is evaluated [ru

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.)

Aspects of the dynamics of heavy-quark systems

International Nuclear Information System (INIS)

Peskin, M.E.

1983-12-01

The analysis of bound states composed of heavy quarks and antiquarks has provided a window into the structure of the strong interactions. These systems contain our best evidence that the quarks from which the hadrons are built are ordinary fermions which obey the Dirac equation and which couple to electromagnetism just as electrons do. However, the heavy-quark systems which have been studied to date, the systems of c- anti c and b- anti b bound states, seem to be bound by forces which bear no obvious relation to the gluons which we expect are the fundamental mediators of the strong interactions. The essential difficulty in understanding this connection arises from the fact that the c- anti c and b- anti b systems occupy an intermediate regime in the behavior of the gauge theory. At very small distances the q- anti q potential is expected to become a Coulomb potential, directly reflecting one-gluon exchange. At very large distances, the potential should be proportional to the q- anti q separation, reflecting the formation of confining strings of color flux. For a proper understanding, one would need to see precisely how the collective behavior of gluons modifies and alters single gluon effects. We seem very far from such a detailed understanding. It is possible, however, to gain some insight into the nature of this intermediate regime by considering the behavior of q- anti q systems from a broad perspective, assembling a variety of distinct aspects of these systems which are sensitive to the properties of gauge theories at intermediate distances. 46 references

Far-from-equilibrium heavy quark energy loss at strong coupling

CERN Document Server

Chesler, Paul; Rajagopal, Krishna

2013-01-01

We study the energy loss of a heavy quark propagating through the matter produced in the collision of two sheets of energy [1]. Even though this matter is initially far-from-equilibrium we find that, when written in terms of the energy density, the equilibrium expression for heavy quark energy loss describes most qualitative features of our results well. At later times, once a plasma described by viscous hydrodynamics has formed, the equilibrium expression describes the heavy quark energy loss quantitatively. In addition to the drag force that makes it lose energy, a quark moving through the out-of-equilibrium matter feels a force perpendicular to its velocity.

Why heavy and light quarks radiate energy with similar rates

International Nuclear Information System (INIS)

Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

2010-01-01

The dead-cone effect has been predicted to reduce the magnitude of energy loss and jet quenching for heavy flavors produced with large p T in heavy-ion collisions. On the contrary, data from the Relativistic Heavy Ion Collider demonstrate a strong suppression of high-p T electrons from charm and bottom decays. We show that vacuum radiation of a highly virtual quark produced at high p T with a stripped-off color field develops a much wider dead cone, which screens the one related to the quark mass. Lacking the field, gluons cannot be radiated within this cone until the color field is regenerated and the quark virtuality cools down to the scale of the order of the quark mass. However, this takes longer than is essential for the observed jet quenching, leading to similar nuclear effects for the light and charm quark jets. Open beauty is expected to radiate much less within the p T range studied so far in heavy-ion collisions.

Heavy quark physics in ep collisions at LEP+LHC

International Nuclear Information System (INIS)

Ali, A.; Barreiro, F.; Troconiz, J.F. de; Schuler, G.A.; Bij, J.J. van der

1990-12-01

We study electroweak production of heavy quarks - charm, beauty, and top - in deep inelastic electron-proton collisions at the proposed LEP+LHC collider at CERN. The assumed energy for the collisions is E e =50 GeV, E p =8000 GeV, providing an ep center of mass energy, √s≅1.26 TeV. We invoke the boson-gluon fusion model to estimate theoretical cross sections and distributions for the heavy quarks. Higher order QCD corrections are only approximately taken into account, by assuming a (normalization) K-factor of 2 for the charm and beauty quark production rates and incorporating the parton shower cascades. With these assumptions and the parameterization of Eichten et al. for the structure functions (EHLQ, set 1), we find the following cross sections: σ(ep→c+X)≅O(3 μb), σ(ep→b+X)≅O(40 nb), and σ(ep→t+X)≅4 pb for m t =120 GeV, decreasing to 0.5 pb for m t =250 GeV. These cross sections would provide O(6x10 9 ) charmed hadrons, O(8x10 7 ) beauty hadrons, and O(10 3 ) top hadrons, for an integrated ep luminosity of 1000 pb -1 . The heavy quark rates in ep collisions are considerably smaller than the corresponding rates in pp collisions at LHC, with √s=16 TeV. This gives a clear advantage to pp collisions for top searches. However, for the charmed and beauty quarks only a tiny fraction of the cross sections in p+p→Q+X can be triggered in comparison to the corresponding cross sections in e+p→Q+X, resulting in comparable number of measured heavy quark events in the ep and pp mode. We sketch the energy-momentum profile of heavy quark events in ep collisions and illustrate the kind of analyses that experiments at the LEP+LHC collider would undertake to quantitatively study heavy quark physics. In particular, prospects of measuring the particle-antiparticle mixing parameter x s =ΔM/Γ for the B s 0 -anti B s 0 meson system are evaluated, and search strategies for the top quark in ep collisions are presented. (orig.)

The heavy quark search at the LHC

International Nuclear Information System (INIS)

Holdom, Bob

2007-01-01

We explore further the discovery potential for heavy quarks at the LHC, with emphasis on the t' and b' of a sequential fourth family associated with electroweak symmetry breaking. We consider QCD multijets, t t-bar + jets, W + jets and single t backgrounds using event generation based on improved matrix elements and low sensitivity to the modeling of initial state radiation. We exploit a jet mass technique for the identification of hadronically decaying W's and t's, to be used in the reconstruction of the t' or b' mass. This along with other aspects of event selection can reduce backgrounds to very manageable levels. It even allows a search for both t' and b' in the absence of b-tagging, of interest for the early running of the LHC. A heavy quark mass of order 600 GeV is motivated by the connection to electroweak symmetry breaking, but our analysis is relevant for any new heavy quarks with weak decay modes

Hot QCD equations of state and relativistic heavy ion collisions

Science.gov (United States)

Chandra, Vinod; Kumar, Ravindra; Ravishankar, V.

2007-11-01

We study two recently proposed equations of state obtained from high-temperature QCD and show how they can be adapted to use them for making predictions for relativistic heavy ion collisions. The method involves extracting equilibrium distribution functions for quarks and gluons from the equation of state (EOS), which in turn will allow a determination of the transport and other bulk properties of the quark gluon-plasma. Simultaneously, the method also yields a quasiparticle description of interacting quarks and gluons. The first EOS is perturbative in the QCD coupling constant and has contributions of O(g5). The second EOS is an improvement over the first, with contributions up to O[g6ln(1/g)]; it incorporates the nonperturbative hard thermal contributions. The interaction effects are shown to be captured entirely by the effective chemical potentials for the gluons and the quarks, in both cases. The chemical potential is seen to be highly sensitive to the EOS. As an application, we determine the screening lengths, which are, indeed, the most important diagnostics for QGP. The screening lengths are seen to behave drastically differently depending on the EOS considered and therefore yield a way to distinguish the two equations of state in heavy ion collisions.

Long-distance behavior of the quark-antiquark static potential. Application to light-quark mesons and heavy quarkonia

International Nuclear Information System (INIS)

Gonzalez, P.

2009-01-01

Screening effects from sea pairs on the quark-antiquark static potential are analyzed phenomenologically from the light-quark to the heavy-quark meson spectra. From the high excited light-quark meson spectrum, a universal form for the screened static potential is proposed. This potential is then successfully applied to heavy quarkonia. Our results suggest the assignment of X(4260) to the 4s state of charmonium and the possible existence of a 5s bottomonium resonance around 10748 MeV.

Heavy quark energy loss far from equilibrium in a strongly coupled collision

CERN Document Server

Chesler, Paul M; Rajagopal, Krishna

2013-01-01

We compute and study the drag force acting on a heavy quark propagating through the matter produced in the collision of two sheets of energy in a strongly coupled gauge theory that can be analyzed holographically. Although this matter is initially far from equilibrium, we find that the equilibrium expression for heavy quark energy loss in a homogeneous strongly coupled plasma with the same instantaneous energy density or pressure as that at the location of the quark describes many qualitative features of our results. One interesting exception is that there is a time delay after the initial collision before the heavy quark energy loss becomes significant. At later times, once a liquid plasma described by viscous hydrodynamics has formed, expressions based upon assuming instantaneous homogeneity and equilibrium provide a semi-quantitative description of our results - as long as the rapidity of the heavy quark is not too large. For a heavy quark with large rapidity, the gradients in the velocity of the hydrodyna...

The average kinetic energy of the heavy quark in Λb in the Bethe-Salpeter equation approach

International Nuclear Information System (INIS)

Guo, X.-H.; Wu, H.-K.

2007-01-01

In the previous paper, based on the SU(2) f xSU(2) s heavy quark symmetries of the QCD Lagrangian in the heavy quark limit, the Bethe-Salpeter equation for the heavy baryon Λ b was established with the picture that Λ b is composed of a heavy quark and a scalar light diquark. In the present work, we apply this model to calculate μ π 2 for Λ b , the average kinetic energy of the heavy quark inside Λ b . This quantity is particularly interesting since it can be measured in experiments and since it contributes to the inclusive semileptonic decays of Λ b when contributions from higher order terms in 1/M b expansions are taken into account and consequently influences the determination of the Cabibbo-Kobayashi-Maskawa matrix elements V ub and V cb . We find that μ π 2 for Λ b is 0.25GeV 2 ∼0.95GeV 2 , depending on the parameters in the model including the light diquark mass and the interaction strength between the heavy quark and the light diquark in the kernel of the BS equation. We also find that this result is consistent with the value of μ π 2 for Λ b which is derived from the experimental value of μ π 2 for the B meson with the aid of the heavy quark effective theory

Quark-level analogue of nuclear fusion with doubly heavy baryons.

Science.gov (United States)

Karliner, Marek; Rosner, Jonathan L

2017-11-01

The essence of nuclear fusion is that energy can be released by the rearrangement of nucleons between the initial- and final-state nuclei. The recent discovery of the first doubly charmed baryon , which contains two charm quarks (c) and one up quark (u) and has a mass of about 3,621 megaelectronvolts (MeV) (the mass of the proton is 938 MeV) also revealed a large binding energy of about 130 MeV between the two charm quarks. Here we report that this strong binding enables a quark-rearrangement, exothermic reaction in which two heavy baryons (Λ c ) undergo fusion to produce the doubly charmed baryon and a neutron n (), resulting in an energy release of 12 MeV. This reaction is a quark-level analogue of the deuterium-tritium nuclear fusion reaction (DT → 4 He n). The much larger binding energy (approximately 280 MeV) between two bottom quarks (b) causes the analogous reaction with bottom quarks () to have a much larger energy release of about 138 MeV. We suggest some experimental setups in which the highly exothermic nature of the fusion of two heavy-quark baryons might manifest itself. At present, however, the very short lifetimes of the heavy bottom and charm quarks preclude any practical applications of such reactions.

Two different formulations of the heavy quark effective theory

International Nuclear Information System (INIS)

Balk, S.; Ilakovac, A.; Koerner, J.G.; Pirjol, D.

1994-01-01

We point out that there exist two different formulations of the Heavy Quark Effective Theory (HQET). The one formulation of HQET was mostly developed at Harvard and involves the use of the equation of motion to eliminate the small components of the heavy quark field. The second formulation, developed in Mainz, involves a series of Foldy-Wouthuysen-type field transformations which diagonalizes the heavy quark Lagrangian in terms of an effective quark and antiquark sector. Starting at O(1/m Q 2 ) the two formulations are different in that their effective Lagrangians, their effective currents, and their effective wave functions differ. However, when these three differences are properly taken into account, the two alternative formulations lead to identical transition or S-matrix elements. This is demonstrated in an explicit example at O(1/m Q 2 ). We point to an essential difficulty of the Harvard HQET in that the Harvard effective fields are not properly normalized starting at order O(1/m Q 2 ). We provide explicit higher order expressions for the effective fields and the Lagrangian in the Mainz approach, and write down an O(1/m Q 2 ) nonabelian version of the Pauli equation for the heavy quark effective field. (orig.)

Heavy quark and magnetic moment

International Nuclear Information System (INIS)

Mubarak, Ahmad; Jallu, M.S.

1979-01-01

The magnetic moments and transition moments of heavy hadrons including the conventional particles are obtained under the SU(5) truth symmetry scheme. To this end state vectors are defined and the quark additivity principle is taken into account. (author)

Several crucial problems in evaluating spectra of baryons with two heavy quarks

International Nuclear Information System (INIS)

Tong Shengping; Ding Yibing; Guo Xinheng; Shen Pengnian; Li Xueqian; Zhang Rui

2000-01-01

The spectra of baryons which include two heavy quarks and one light quark can be treated as a two-body system, where two heavy quarks constitute a bosonic diquark. The authors derive the effective potential between the light quark and the heavy diquark. In this work authors have discussed several serious problems: (1) the operator ordering, (2) the errors caused by the non-relativistic expansion, (3) spin-spin coupling and (4) the mixing between baryon states with scalar-diquark and vector-diquark

Are there heavy quarks of mass 23 GeV

International Nuclear Information System (INIS)

Cornet, F.; Hagiwara, K.; Zeppenfeld, D.; Glover, E.W.N.; Martin, A.D.

1986-02-01

An excess of events with an isolated muon and low thrust observed by the MARK-J collaboration at the highest PETRA energy √s=46.7 GeV, is found to be consistent with the near threshold production of heavy quarks of charge -1/3. A natural candidate is a fourth generation 'down' quark or, possibly, a member of a 27 representation of E 6 . We investigate signatures of such heavy quark pair production at the CERN panti p collider and conclude that the present data have a chance to confirm the signal. (orig.)

Enhanced breaking of heavy quark spin symmetry

Energy Technology Data Exchange (ETDEWEB)

Guo, Feng-Kun, E-mail: fkguo@hiskp.uni-bonn.de [Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Meißner, Ulf-G., E-mail: meissner@hiskp.uni-bonn.de [Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Shen, Cheng-Ping, E-mail: shencp@ihep.ac.cn [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China)

2014-11-10

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(Λ{sub QCD}/m{sub Q}), with Λ{sub QCD} the scale of QCD and m{sub Q} 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 χ{sub bJ}ω(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)→χ{sub b0}ω)/Γ(ϒ(10860)→χ{sub b2}ω) is presented assuming that the decay of the D-wave component is dominated by the coupled-channel effects.

Heavy quarks thermalization in heavy-ion ultrarelativistic collisions: elastic or radiative?

International Nuclear Information System (INIS)

Gossiaux, Pol Bernard; Guiho, Vincent; Aichelin, Joerg

2006-01-01

We present a dynamical model of heavy quark evolution in the quark-gluon plasma (QGP) based on the Fokker-Planck equation. We then apply this model to the case of ultrarelativistic nucleus-nucleus collisions performed at RHIC in order to investigate which experimental observables might help to discriminate the fundamental process leading to thermalization

QCD measurements with heavy quarks at LEP

International Nuclear Information System (INIS)

Maettig, P.

1991-10-01

Recent experimental results from LEP on strong interactions using heavy quarks are reviewed. By identifying bottom and charm decays, a model independent evidence for the string effect has been found together with a softer fragmentation function of gluons compared to quarks. The comparison of jet properties and the value of the strong coupling constant α s in bottom events and average events provides evidence for the flavour independence of QCD: α b0tt0m s /α s udsc = 1.00 ± 0.05 ± 0.06. The average scaled energy of charmed and bottom hadrons at Z 0 energies is found to be + )> = 0.507 +0.012 -0.015 ± 0.010 = 0.705 ± 0,008 ± 0.010. A comparison with results at lower c.m. energies exhibits significant scaling violations. These are interpreted in the context of various QCD calculations. (orig.)

The mass spectrum of double heavy baryons in new potential quark models

Directory of Open Access Journals (Sweden)

Kovalenko Vladimir

2017-01-01

Full Text Available A new approach to study the mass spectrum of double heavy baryons (QQ′q containing strange and charmed quarks is proposed. It is based on the separation of variables in the Schrodinger equation in the prolate spheroidal coordinates. Two nonrelativistic potential models are considered. In the first model, the interaction potential of the quarks is the sum of the Coulomb and non-spherically symmetrical linear confinement potential. In the second model it is assumed that the quark confinement provided by a spherically symmetric harmonic oscillator potential. In both models the mass spectrum is calculated, and a comparison with previous results from other models is performed.

Masses and decay constants of bound states containing fourth family quarks from QCD sum rules

International Nuclear Information System (INIS)

Bashiry, V.; Azizi, K.; Sultansoy, S.

2011-01-01

The heavy fourth generation of quarks that have sufficiently small mixing with the three known standard model families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from the fourth family and the other from known third family standard model quarks in the framework of the QCD sum rules. In the calculations, we take into account two-gluon condensate diagrams as nonperturbative contributions. The obtained results reduce to the known masses and decay constants of the bb and cc quarkonia when the fourth family quark is replaced by the bottom or charm quark.

Running heavy-quark masses in DIS

International Nuclear Information System (INIS)

Alekhin, S.; Moch, S.

2011-07-01

We report on determinations of the running mass for charm quarks from deep-inelastic scattering reactions. The method provides complementary information on this fundamental parameter from hadronic processes with space-like kinematics. The obtained values are consistent with but systematically lower than the world average as published by the PDG. We also address the consequences of the running mass scheme for heavy-quark parton distributions in global fits to deep-inelastic scattering data. (orig.)

Heavy quark symmetry at large recoil: The case of baryons

International Nuclear Information System (INIS)

Koerner, J.G.; Kroll, P.

1992-02-01

We analyze the large recoil behaviour of heavy baryon transition form factors in semi-leptonic decays. We use a generalized Brodsky-Lepage hard scattering formalism where diquarks are considered as quasi-elementary constituents of baryons. In the limit of infinitely heavy quark masses the large recoil form factors exhibit a new model-independent heavy quark symmetry which is reminiscent but not identical to the Isgur-Wise symmetry at low recoil. (orig.)

A non-perturbative operator product expansion

International Nuclear Information System (INIS)

Bietenholz, W.; Cundy, N.; Goeckeler, M.

2009-10-01

Nucleon structure functions can be observed in Deep Inelastic Scattering experiments, but it is an outstanding challenge to confront them with fully non-perturbative QCD results. For this purpose we investigate the product of electromagnetic currents (with large photonmomenta) between quark states (of low momenta). By means of an Operator Product Expansion the structure function can be decomposed into matrix elements of local operators, and Wilson coefficients. For consistency both have to be computed non-perturbatively. Here we present precision results for a set of Wilson coefficients. They are evaluated from propagators for numerous quark momenta on the lattice, where the use of chiral fermions suppresses undesired operator mixing. This overdetermines the Wilson coefficients, but reliable results can be extracted by means of a Singular Value Decomposition. (orig.)

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

International Nuclear Information System (INIS)

Cohen, Thomas D.; Kumar, Nilay; Ndousse, Kamal K.

2011-01-01

This paper explores properties of baryons and finite density baryonic matter in an artificial world in which N c , the number of colors, is large and the quarks of all species are degenerate and much larger than Λ QCD . It has long been known that in large N c quantum chromodynamics (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 N c 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 N c and heavy-quark expansions the baryon mass is shown to be M baryon ≅N c M Q (1-0.054 26α-tilde s 2 ), where α-tilde s ≡N c α s . The baryon form factor is also computed. 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 N c limit interactions between baryons are strictly repulsive at low densities. The energy per baryon is computed in this limit and found to be exponentially small. It is shown that when the restriction to baryons with an identical spin-flavor structure is dropped, a phase of baryonic matter exists with a density of 2N f times that for the restricted case but with the same energy (where N f is the number of degenerate flavors). It is shown that this phase is at least metastable.

FY07 LDRD Final Report Heavy Quark Jet Tomography

International Nuclear Information System (INIS)

Soltz, R.; Newby, J.; Glenn, A.; Klay, J.

2008-01-01

We propose and develop a new signature, the measurement of hadron-electron correlations to measure energy loss of heavy quarks in the quark-gluon plasma. This measurements will be used in future analyses to quantify the energy densities created in collisions of heavy ions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab and the Large Hadron Collider (LHC) at CERN. In addition we develop and implement a computing model that will leverage LLNL expertise in cost-effective high performance computing to perform data analyses and simulations for the ALICE experiment at CERN

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

International Nuclear Information System (INIS)

Jiang, Bing-feng; Hou, De-fu; Li, Jia-rong

2016-01-01

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.

Gauge-invariant, nonperturbative approach to the infrared-finite bound-state problem in QCD

International Nuclear Information System (INIS)

Gogokhia, V.Sh.

1989-09-01

Gauge invariant, nonperturbative approach to the bound state problem within the infrared finite Bethe-Salpeter equation is presented. Condition of cancellation of the nonperturbative infrared divergences is derived. Solutions for the quark propagator and corresponding quark gluon vertex function are written down which can be directly applied to the Bethe-Salpeter equation, in particular to the 'generalized ladder' approximation of this equation. (author) 18 refs.; 3 figs

Heavy quark fragmentation into polarized quarkonium in the heavy quark effective theory

International Nuclear Information System (INIS)

Martynenko, A.P.; Saleev, V.A.

1996-01-01

Fragmentation of b-antiquark into polarized B* c -mesons is investigated within the framework of effective theory of heavy quarks. Functions of b fragmentation into longitudinally polarized and transversely polarized S-wave states of b c are calculated with an exact regard tot he first order corrections by 1/m b . Agreement of the results obtained with the corresponding calculations, performed in the quantum chromodynamics, is shown. 17 refs.; 2 figs

Decay constants in the heavy quark limit in models a la Bakamjian and Thomas

International Nuclear Information System (INIS)

Morenas, V.; Le Yaouanc, A.; Oliver, L.; Pene, O.; Raynal, J.C.

1997-07-01

In quark models a la Bakamjian and Thomas, that yield covariance and Isgur-Wise scaling of form factors in the heavy quark limit, the decay constants f (n) and f 1/2 (n) of S-wave and P-wave mesons composed of heavy and light quarks are computed. Different Ansaetze for the dynamics of the mass operator at rest are discussed. Using phenomenological models of the spectrum with relativistic kinetic energy and regularized short distance part the decay constants in the heavy quark limit are calculated. The convergence of the heavy quark limit sum rules is also studied. (author)

When is a heavy quark not a parton? Charged Higgs production and heavy quark mass effects in the QCD-based parton model

International Nuclear Information System (INIS)

Olness, F.I.; Tung, Wu-Ki

1989-10-01

Applications of the QCD-based parton model to new physics processes involving heavy partons are illustrated using charged Higgs production. The naive parton model predictions are found to over-estimate the actual cross section by a factor of 2 to 5. The role of the top quark as a ''parton'' is examined, and the energy range over which heavy quarks (or other particles) should or should not be naturally treated as ''partons'' is delineated. 12 refs., 5 figs

Towards OPE based local quark-hadron duality: light-quark channels

International Nuclear Information System (INIS)

Hofmann, Ralf

2002-01-01

Various light-quark channel current-current correlators are subjected to the concept of a non-perturbative component of coarse graining in operator product expansions introduced in a parallel work. This procedure allows for low-energy structure of the OPE-derived spectral function. With naive vacuum saturation for 4-quark operators and using lattice data for the gauge invariant scalar quark correlator the results are far off the experimentally measured behavior. However, using the correlation length of the gauge invariant vector quark correlator, which is about 10 times smaller than the scalar one, the qualitative results are rather realistic. Namely, the input of information on the mass of the lowest resonance in one channel yields the corresponding masses within acceptable errors in other channels. Still, the shapes of the calculated spectral functions are considerably deformed as compared to experiment. This may be a consequence of vacuum saturation and the truncation at a mass dimension which is below the critical dimension from which on the asymptotic expansion does not approximate anymore. To improve on this high-resolution lattice information on gauge invariant n>2 point correlators would be needed. Motivated by the small effective correlation length in the 4-quark contributions the relevance of the approach for heavy quark physics, in particular in the calculation of non-leptonic, inclusive ΔΓ, is discussed

Quark and Gluon Relaxation in Quark-Gluon Plasmas

Science.gov (United States)

Heiselberg, H.; Pethick, C. J.

1993-01-01

The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.

QCD Sum-Rule Calculation of the Kinetic Energy and Chromo-Interaction of Heavy Quarks Inside Mesons

CERN Document Server

Neubert, M

1996-01-01

We present a QCD sum-rule determination of the heavy-quark kinetic energy inside a heavy meson, $-\\lambda_1/2 m_Q$, which is consistent with the field-theory analog of the virial theorem. We obtain $-\\lambda_1\\approx (0.10\\pm 0.05)~\\mbox{GeV}^2$, significantly smaller than a previous sum-rule result, but in good agreement with recent determinations from the analysis of inclusive decays. We also present a new determination of the chromo-magnetic interaction, yielding $\\lambda_2(m_b)=(0.15\\pm 0.03)~\\mbox{GeV}^2$. This implies $m_{B^*}^2-m_B^2=(0.60\\pm 0.12)~\\mbox{GeV}^2$, in good agreement with experiment. As a by-product of our analysis, we derive the QCD sum rules for the three form factors describing the meson matrix element of a velocity-changing current operator containing the gluon field-strength tensor.

Matching of heavy-light flavour currents between HQET at order 1/m and QCD

DEFF Research Database (Denmark)

Della Morte, Michele; Dooling, Samantha; Heitger, Jochen

2014-01-01

We present a strategy how to match the full set of components of the heavy-light axial and vector currents in Heavy Quark Effective Theory (HQET), up to and including 1/m-corrections, to QCD. While the ultimate goal is to apply these matching conditions non-perturbatively, in this study we first...

CP violation for electroweak baryogenesis from mixing of standard model and heavy vector quarks

International Nuclear Information System (INIS)

McDonald, J.

1996-01-01

It is known that the CP violation in the minimal standard model is insufficient to explain the observed baryon asymmetry of the Universe in the context electroweak baryogenesis. In this paper we consider the possibility that the additional CP violation required could originate in the mixing of the standard model quarks and heavy vector quark pairs. We consider the baryon asymmetry in the context of the spontaneous baryogenesis scenario. It is shown that, in general, the CP-violating phase entering the mass matrix of the standard model and heavy vector quarks must be space dependent in order to produce a baryon asymmetry, suggesting that the additional CP violation must be spontaneous in nature. This is true for the case of the simplest models which mix the standard model and heavy vector quarks. We derive a charge potential term for the model by diagonalizing the quark mass matrix in the presence of the electroweak bubble wall, which turns out to be quite different from the fermionic hypercharge potentials usually considered in spontaneous baryogenesis models, and obtain the rate of baryon number generation within the wall. We find, for the particular example where the standard model quarks mix with weak-isodoublet heavy vector quarks via the expectation value of a gauge singlet scalar, that we can account for the observed baryon asymmetry with conservative estimates for the uncertain parameters of electroweak baryogenesis, provided that the heavy vector quarks are not heavier than a few hundred GeV and that the coupling of the standard model quarks to the heavy vector quarks and gauge singlet scalars is not much smaller than order of 1, corresponding to a mixing angle of the heavy vector quarks and standard model quarks not much smaller than order of 10 -1 . copyright 1996 The American Physical Society

Compatibility of various approaches to heavy-quark fragmentation

International Nuclear Information System (INIS)

Bodwin, G. T.; Harris, B. W.

2001-01-01

We find that the definition of the heavy-quark fragmentation function given by Jaffe and Randall differs by a factor of the longitudinal-momentum fraction z from the standard Collins-Soper definition. Once this factor is taken into account, the explicit calculation of Braaten is found to be in agreement with the general analysis of Jaffe and Randall. We also examine the model of Peterson for heavy-quark fragmentation and find that the quoted values of the width and of the value of z at the maximum are in error. The corrected values are in agreement with the analysis of Jaffe and Randall

Analyzing Bs - anti Bs mixing. Non-perturbative contributions to bag parameters from sum rules

International Nuclear Information System (INIS)

Mannel, T.; Pivovarov, A.A.; Russian Academy of Sciecnes, Moscow

2007-03-01

We use QCD sum rules to compute matrix elements of the ΔB=2 operators appearing in the heavy-quark expansion of the width difference of the B s mass eigenstates. Our analysis includes the leading-order operators Q and Q S , as well as the subleading operators R 2 and R 3 , which appear at next-to-leading order in the 1/m b expansion. We conclude that the violation of the factorization approximation for these matrix elements due to non-perturbative vacuum condensates is as low as 1-2%. (orig.)

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.

Search for Dark Matter In events with heavy quarks and missing transverse energy with the ATLAS detector

CERN Document Server

Afik, Yoav; The ATLAS collaboration

2017-01-01

A wide search program is being carried at the LHC under the hypothesis that Dark Matter (DM) consists of weakly interacting massive particles (WIMPs). Final states with heavy flavour quarks and large momentum imbalance represent an interesting discovery signature which allows to probe models with scalar or pseudo-scalar interactions between the Standard Model and the dark sector under the assumption of Minimal Flavour Violation. We present the most recent results of searches for DM produced in association with a pair of heavy flavour quarks (DM+HF) in ATLAS [1-2] based on 36.1 fb-1 of proton-proton collision data collected at a centre of mass energy of 13 TeV.

Hadron production in relativistic heavy ion interactions and the search for the quark-gluon plasma

International Nuclear Information System (INIS)

Tannenbaum, M.J.

1989-12-01

The course starts with an introduction, from the experimentalist's point of view, of the challenge of measuring Relativistic Heavy Ion interactions. A review of some theoretical predictions for the expected signatures of the quark gluon plasma will be made, with a purpose to understand how they relate to quantities which may be experimentally measured. A short exposition of experimental techniques and details is given including charged particles in matter, momentum resolution, kinematics and Lorentz Transformations, calorimetry. Principles of particle identification including magnetic spectrometers, time of flight measurement. Illustrations using the E802 spectrometer and other measured results. Resolution smearing of spectra, and binning effects. Parent to daughter effects in decay, with π 0 → γ γ as an example. The experimental situation from the known data in p -- p collisions and proton-nucleus reactions is reviewed and used as a basis for further discussions. The ''Cronin Effect'' and the ''Seagull Effect'' being two arcana worth noting. Then, selected experiments from the BNL and CERN heavy ion programs are discussed in detail. 118 refs., 45 figs

The coupling of heavy mesons to the pion on the lattice

International Nuclear Information System (INIS)

Herdoiza, G.

2004-04-01

The QCD non-perturbative effects are among the main sources of uncertainty in our present knowledge of the Standard Model phenomenology. I will present some of the methods which can be used to study these effects, and I will particularly treat the case of lattice QCD. Effective theories can be combined to the lattice approach in order to study the chiral and the heavy quark sectors. I will give some examples of how these properties can be successfully applied to the quark flavour phenomenology. The coupling of heavy mesons to the pion is related to a non-perturbative quantity, noted g-bar, which is required to extract physical results from the effective theory combining both chiral and heavy quark symmetry. This coupling is also involved in the study of the form factors appearing in the heavy to light semi-leptonic decays. These heavy meson decays are used to extract some of the CKM matrix elements which are know, up to now, only with large uncertainties. Moreover, the chiral effects of heavy mesons depend on pion loops whose vertices are precisely the coupling g-bar. These are some of the reasons why the theoretical and experimental determination of this coupling is required. I will present the results of its studies on the lattice and I will compare them to those obtained through several other methods. I will therefore describe these different approaches, their limitations and possible improvements, both from the point of view of the method and of its application to the determination of the coupling g-bar. (author)

Deconfinement phase transition in QCD with heavy quarks

International Nuclear Information System (INIS)

Attig, N.; Petersson, B.; Wolff, M.; Gavai, R.V.

1988-01-01

Using the pseudo-fermion method to simulate QCD with dynamical quarks we investigate the effects of heavy dynamical quarks of 2 flavours on the deconfinement phase transition in the quenched QCD. As the mass of the quark is decreased the phase transition weakens as expected. Compared to the earlier results with leading order hopping parameter expansion, however, the weakening is less rapid. Our estimated upper bound on the critical mass where the transition becomes continuous is 1.5-2 times lower than earlier results. (orig.)

Renormalisaton of composite operators in lattice QCD. Perturbative versus nonperturbative

Energy Technology Data Exchange (ETDEWEB)

Goeckeler, M.; Nakamura, Y. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (GB). School of Physics and Astronomy] (and others)

2010-07-01

The perturbative and nonperturbative renormalisation of quark-antiquark operators in lattice QCD with two flavours of clover fermions is investigated within the research programme of the QCDSF collaboration. Operators with up to three derivatives are considered. The nonperturbative results based on the RI-MOM scheme are compared with estimates from one- and two-loop lattice perturbation theory. (orig.)

Proceedings of the Helmholtz international school physics of heavy quarks and hadrons (HQ2013)

International Nuclear Information System (INIS)

Ali, Ahmed; Bystritskiy, Yury; Ivanov, Mikhail

2014-07-01

The following topics were dealt with: Higgs boson production and couplings with the ATLAS detector, recent CMS results on heavy quarks and hadrons, mesons with open charm and beauty, new-physics searches in B→D (*) τν τ , spectroscopy and Regge trajectories of heavy quarkonia, weak decays of B s mesons, the possible role of scalar glueball-quarkonia mixing in the f 0 (1370,1500,17100) resonances produced in charmonia decays, effective weak Lagrangians in the Standard Model and B decays, heavy-quark physics in the covariant quark model, application of QCD sum rules to heavy-quark physics, top-quark production, helicity amplitudes and angular decay distributions, small-x behavior of deep-inelastic structure functions F 2 and F 2 cc , XYZ stated, recent Belle results, light and heavy hadrons in AdS/QCD, renorm dynamics, valence quarks and multiparticle production, prompt photons and associated b,c-tagged jet production within the k T factorization approach, heavy quarkonium production at the LHC in the framework of NRQCD and parton Reggeization approach, light-cone distribution amplitudes of bottom baryons, rare semileptonic B + → π + l + l - decay, bimodality phenomenon in finite and infinite systems within an exactly solvable statistical model, CP violation in D meson decays, the scalar mesons in multichannel ππ scattering and decays of the ψ and Υ families, the latest results of the ATLAS experiment on heavy-quark physics, relativistic corrections to pair charmonium production at the LHC, the rise and fall of the fourth quark-lepton generation. (HSI)

Quark color-hyperfine interactions in baryons

International Nuclear Information System (INIS)

Anselmino, M.; Lichtenberg, D.B.

1990-01-01

We consider the contribution from the color-hyperfine interaction to the energies of groundstate hadrons, with an emphasis on baryons. We use experimental information about how the color-hyperfine term depends on flavor to make predictions about the masses of baryons containing a heavy quark. We then generalize some relations between color-hyperfine matrix elements in mesons and baryons to obtain a number of additional predictions about the masses of as-yet unobserved baryons. Most of our predictions are in the form of inequalities. (orig.)

Non-perturbative QCD Effect on K-Factor of Drell-Yan Process

International Nuclear Information System (INIS)

Hou Zhaoyu; Zhi Haisu; Chen Junxiao

2006-01-01

By using a non-perturbative quark propagator with the lowest-dimensional condensate contributions from the QCD vacuum, the non-perturbative effect to K-factor of the Drell-Yan process is numerically investigated for 12 6 C- 12 6 C collision at the center-of-mass energy (s) 1/2 = 200 GeV, 630 GeV respectively. Calculated results show that the non-perturbative QCD effect has just a weak influence on K-factor in the two cases.

Ellipsoidal bag model for heavy quark system

International Nuclear Information System (INIS)

Bi Pinzhen; Fudan Univ., Shanghai

1991-01-01

The ellipsoidal bag model is used to describe heavy quark systems such as Qanti Q, Qanti Qg and Q 2 anti Q 2 . Instead of two step model, these states are described by an uniform picture. The potential derived from the ellipsoidal bag for Qanti Q is almost equivalent to the Cornell potential. For a Q 2 anti Q 2 system with large quark pair separation, an improvement of 70 MeV is obtained comparing with the spherical bag. (orig.)

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

Science.gov (United States)

Burnier, Yannis; Kaczmarek, Olaf; Rothkopf, Alexander

2016-01-01

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 323 × Nτ (β = 7.0, ξ = 3.5) lattices with Nτ = 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 Nf = 2 + 1 ASQTAD lattices with ml = ms/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.

Quark and gluon production from a boost-invariantly expanding color electric field

Science.gov (United States)

Taya, Hidetoshi

2017-07-01

Particle production from an expanding classical color electromagnetic field is extensively studied, motivated by the early stage dynamics of ultrarelativistic heavy ion collisions. We develop a formalism at one-loop order to compute the particle spectra by canonically quantizing quark, gluon, and ghost fluctuations under the presence of such an expanding classical color background field; the canonical quantization is done in the τ -η coordinates in order to take into account manifestly the expanding geometry. As a demonstration, we model the expanding classical color background field by a boost-invariantly expanding homogeneous color electric field with lifetime T , for which we obtain analytically the quark and gluon production spectra by solving the equations of motion of QCD nonperturbatively with respect to the color electric field. In this paper we study (i) the finite lifetime effect, which is found to modify significantly the particle spectra from those expected from the Schwinger formula; (ii) the difference between the quark and gluon production; and (iii) the quark mass dependence of the production spectra. Implications of these results to ultrarelativistic heavy ion collisions are also discussed.

Nuclear matter from effective quark-quark interaction.

Science.gov (United States)

Baldo, M; Fukukawa, K

2014-12-12

We study neutron matter and symmetric nuclear matter with the quark-meson model for the two-nucleon interaction. The Bethe-Bruckner-Goldstone many-body theory is used to describe the correlations up to the three hole-line approximation with no extra parameters. At variance with other nonrelativistic realistic interactions, the three hole-line contribution turns out to be non-negligible and to have a substantial saturation effect. The saturation point of nuclear matter, the compressibility, the symmetry energy, and its slope are within the phenomenological constraints. Since the interaction also reproduces fairly well the properties of the three-nucleon system, these results indicate that the explicit introduction of the quark degrees of freedom within the considered constituent quark model is expected to reduce the role of three-body forces.

A Proposal to Study Beauty Production and Other Heavy Quark Physics Associated with Dimuon Production in 800 (925) GeV/C pp Interactions

Energy Technology Data Exchange (ETDEWEB)

Arenton, M.; Chen, T.Y.; Lai, K.W.; Yao, N.; /Arizona U.; Anassontzis, S.E.; Katsanevas, S.; Kourkoumelis, C.; Ioannu, P.; Premantiotis, T.; Manousakis-Kaftsikakis, A.; Resvanis, L.K.; /Athens U. /Duke U. /Fermilab /Florida A-M /McGill U. /Northwestern U. /Shandong U.

1986-05-01

The presence of dimuons in final states produced in hadronic interactions has proved to be a valuable indicator that interesting hard physics processes have taken place. These muon pairs provide a mechanism for selecting these relatively rare processes from interactions due to the total cross section. In particular, processes involving heavy quarks are flagged by the presence of muon pairs. We are proposing to use the high rate E705 spectrometer and its dimuon trigger processor which have already functioned well in Experiments E-537 and E-705 to detect and measure several heavy quark phenomena which result in a final state containing a pair of muons. This experiment will use the primary proton beam from the Tevatron at the maximum energy available at the time of execution of the experiment. The spectrometer will be augmented by the addition of a silicon tracker similar to those used in other experiments at the Fermilab. The present P-West High Intensity Laboratory secondary beams will need to be upgraded by addition of sufficient bending power to allow the transport of the 800 to 925 GeV/c primary proton beam to the experiment target (see Appendix A).

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.

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

International Nuclear Information System (INIS)

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 0 decays at CERN; recent K 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 ρ bar ρ collider; B physics at CDF; and review of particle astrophysics

Search for heavy quarks at panti p colliders

International Nuclear Information System (INIS)

Kroll, I.J.

1989-01-01

At present, the Fermilab and CERN panti p colliders with √s = 1.8 TeV and 0.63 TeV, respectively, provide the highest mass reach of existing accelerators for finding new particles. In particular, these colliders can be used to search for heavy quarks. The upper limit of 1.2x10 -3 (90% CL) on BR(B 0 → μ + μ - X) is strong indirect evidence that the charge 2/3 SU(2) partner of the bottom quark, usually called the top quark, exists. In addition, present experimental data do not exclude a fourth generation of quarks and leptons. A search for a fourth-generation, charge 1/3 quark (here referred to as the b' quark) should be made. The present limits from e + e - colliders on the masses of these particles are m t > 27.4 GeV/c 2 (95% CL) and m b ' > 25.5 GeV/c 2 (95% CL). (orig.)

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.

Recent progress in nonperturbative electromagnetic lepton-pair production with capture in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Wells, J.C.; Oberacker, V.E.; Umar, A.S.

1993-01-01

The prospect of new colliding-beam accelerators capable of producing collisions of highly stripped high-Z ions, at fixed-target energies per nucleon up to 20 TeV or more, has motivated much interest in lepton-pair production from the QED vacuum. The time-dependent and essentially classical electromagnetic fields involved in such collisions contain larger Fourier components which give rise to sizable lepton-pair production in addition to many other exotic particles. The process of electron-positron production with electron capture is a principal beam-loss mechanism for highly charged ions in a storage ring. In this process, the electron is created in a bound state of one of the participant heavy ions (most likely the 1s state), thus changing the ion's charge state and causing it to be deflected out of the beam. There is a long and sometimes controversial history concerning the use of perturbative methods in studying electromagnetic lepton-pair production; however, reliable perturbative calculations have been used as input into design models for the Relativistic Heavy-Ion Collider (RHIC). Applying perturbation theory to these processes at high energies and small impact parameters results in probabilities which violate unitarity, and cross sections which violate the Froissart bound. This evidence, along with the initial nonperturbative studies, suggests that higher-order QED effects will be important for extreme relativistic collisions. Clearly, large nonperturbative effects in electron-pair production with capture would have important implications for RHIC. In this paper, the authors briefly discuss recent progress in nonperturbative studies of the capture problem. In Section 2, they state the Dirac equation for a lepton in the time-dependent external field of a heavy ion which must be solved to compute lepton-capture probabilities. Section 4 surveys results from recent applications of coupled-channel and lattice techniques to the lepton-capture problem

Ground-state triply and doubly heavy baryons in a relativistic three-quark model

International Nuclear Information System (INIS)

Martynenko, A.P.

2008-01-01

Mass spectra of the ground-state baryons consisting of three or two heavy (b or c) and one light (u,d,s) quarks are calculated in the framework of the relativistic quark model and the hyperspherical expansion. The predictions of masses of the triply and doubly heavy baryons are obtained by employing the perturbation theory for the spin-independent and spin-dependent parts of the three-quark Hamiltonian

Status and prospects for lattice calculations in heavy quark physics

International Nuclear Information System (INIS)

Wittig, H.; Forschungszentrum Juelich GmbH

1996-06-01

The current status of lattice calculation of weak matrix elements for heavy quark systems is reviewed. After an assessment of systematic errors in present simulations, results for the B meson decay constant, the B parameter B B and semi-leptonic heavy-to-light and heavy-to-heavy transitions are discussed. The final topic are lattice results for heavy baryon spectroscopy. (orig.)

Semileptonic Decays of Heavy Lambda Baryons in a Quark Model

Energy Technology Data Exchange (ETDEWEB)

Winston Roberts; Muslema Pervin; Simon Capstick

2005-03-01

The semileptonic decays of {Lambda}{sub c} and {Lambda}{sub b} are treated in the framework of a constituent quark model. Both nonrelativistic and semirelativistic Hamiltonians are used to obtain the baryon wave functions from a fit to the spectra, and the wave functions are expanded in both the harmonic oscillator and Sturmian bases. The latter basis leads to form factors in which the kinematic dependence on q{sup 2} is in the form of multipoles, and the resulting form factors fall faster as a function of q{sup 2} in the available kinematic ranges. As a result, decay rates obtained in the two models using the Sturmian basis are significantly smaller than those obtained using the harmonic oscillator basis. In the case of the {Lambda}{sub c}, decay rates calculated using the Sturmian basis are closer to the experimentally reported rates. However, we find a semileptonic branching fraction for the {Lambda}{sub c} to decay to excited {Lambda}* states of 11% to 19%, in contradiction with what is assumed in available experimental analyses. Our prediction for the {Lambda}{sub b} semileptonic decays is that decays to the ground state {Lambda}{sub c} provide a little less than 70% of the total semileptonic decay rate. For the decays {Lambda}{sub b} {yields} {Lambda}{sub c}, the analytic form factors we obtain satisfy the relations expected from heavy-quark effective theory at the non-recoil point, at leading and next-to-leading orders in the heavy-quark expansion. In addition, some features of the heavy-quark limit are shown to naturally persist as the mass of the heavy quark in the daughter baryon is decreased.

Heavy quarks fragmentation in charmed mesons in DELPHI experiment at LEP

International Nuclear Information System (INIS)

Levy, J.M.

1994-04-01

With the big statistics expected at LEP, the electroweak sector of the Standard Model can be tested as well as the theory of strong interactions. Quantum Chromo-Dynamics is indeed predictive for quarks properties, but does not explain how quarks fragment into hadrons. So far the hadronization can only be described with phenomenological models. The work presented in this thesis was performed on the DELPHI experiment at LEP and concerns the production and the fragmentation of heavy quarks into charmed mesons D , D* and D**. With the whole statistics of 1991 and 1992 (1 013 300 hadronic decays of the Z), more than 4500 charmed mesons decays have been reconstructed in the channels D 0 → K - π + , D + → K - π + π+ and D * +→ D 0 π + followed by D 0 → K - π + . Using also 1993 data and the channel D 0 → K - π + π + π - , evidence for D** production is presented. For the first time, the production rate is measured for each D meson separately for cc and bb contributions. In fact, D mesons can be produced either directly from the fragmentation of c quark or un-directly from the fragmentation of b quark into B mesons which decay into D mesons. (authors). 120 refs

Renormalisation constants of quark bilinears in lattice QCD with four dynamical Wilson quarks

NARCIS (Netherlands)

Blossier, B.; Brinet, M.; Carrasco, N.; Dimopoulos, P.; Du, X.; Frezzotti, R.; Gimenez, V.; Herdoiza, G.; Jansen, K.; Lubicz, V.; Palao, D.; Pallante, E.; Pene, O.; Petrov, K.; Reker, S.; Rossi, G. C.; Sanfilippo, F.; Scorzato, L.; Simula, S.; Urbach, C.

2011-01-01

We present preliminary results of the non-perturbative computation of the RI-MOM renormalisation constants in a mass-independent scheme for the action with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our project requires dedicated gauge ensembles with four degenerate sea quark

Physical and cut-off effects of heavy sea quarks

CERN Document Server

Knechtli, Francesco; Bruno, Mattia; Finkenrath, Jacob; Leder, Björn; Marinkovic, Marina; Sommer, Rainer

2014-01-01

We simulate a theory with two dynamical O($a$) improved Wilson quarks whose mass $M$ ranges from a factor eight up to a factor two below the charm quark mass and at three values of the lattice spacing ranging from 0.066 to 0.034 fm. This theory is a prototype to study the decoupling of heavy quarks. We measure the mass and cut-off dependence of ratios of gluonic observables defined from the Wilson flow or the static potential. The size of the 1/$M$ corrections can be determined and disentangled from the lattice artifacts. The difference with the pure gauge theory is at the percent level when two quarks with a mass of the charm quark are present.

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.

Lattice Yang-Mills theory at finite densities of heavy quarks

International Nuclear Information System (INIS)

Langfeld, Kurt; Shin, Gwansoo

2000-01-01

SU(N c ) Yang-Mills theory is investigated at finite densities of N f heavy quark flavors. The calculation of the (continuum) quark determinant in the large-mass limit is performed by analytic methods and results in an effective gluonic action. This action is then subject to a lattice representation of the gluon fields and computer simulations. The approach maintains the same number of quark degrees of freedom as in the continuum formulation and a physical heavy quark limit (to be contrasted with the quenched approximation N f →0). The proper scaling towards the continuum limit is manifest. We study the partition function for given values of the chemical potential as well as the partition function which is projected onto a definite baryon number. First numerical results for an SU(2) gauge theory are presented. We briefly discuss the breaking of the color-electric string at finite densities and shed light onto the origin of the overlap problem inherent in the Glasgow approach

Heavy Quark Effective Theory

Science.gov (United States)

Manohar, A. V.

2003-02-01

These lecture notes present some of the basic ideas of heavy quark effective theory. The topics covered include the classification of states, the derivation of the HQET Lagrangian at tree level, hadron masses, meson form factors, Luke's theorem, reparameterization invariance and inclusive decays. Radiative corrections are discussed in some detail, including an explicit computation of a matching correction for HQET. Borel summability, renormalons, and their connection with the QCD perturbation series is covered, as well as the use of the upsilon expansion to improve the convergence of the perturbation series.

Semileptonic Decays of Heavy Omega Baryons in a Quark Model

International Nuclear Information System (INIS)

Muslema Pervin; Winston Roberts; Simon Capstick

2006-01-01

The semileptonic decays of (Omega) c and (Omega) b are treated in the framework of a constituent quark model developed in a previous paper on the semileptonic decays of heavy Λ baryons. Analytic results for the form factors for the decays to ground states and a number of excited states are evaluated. For (Omega) b to (Omega) c the form factors obtained are shown to satisfy the relations predicted at leading order in the heavy-quark effective theory at the non-recoil point. A modified fit of nonrelativistic and semirelativistic Hamiltonians generates configuration-mixed baryon wave functions from the known masses and the measured Λ c + → Λe + ν rate, with wave functions expanded in both harmonic oscillator and Sturmian bases. Decay rates of (Omega) b to pairs of ground and excited (Omega) c states related by heavy-quark symmetry calculated using these configuration-mixed wave functions are in the ratios expected from heavy-quark effective theory, to a good approximation. Our predictions for the semileptonic elastic branching fraction of (Omega) Q vary minimally within the models we use. We obtain an average value of (84 ± 2%) for the fraction of (Omega) c → Ξ (*) decays to ground states, and 91% for the fraction of (Omega) c → (Omega) (*) decays to the ground state (Omega). The elastic fraction of (Omega) b → (Omega) c ranges from about 50% calculated with the two harmonic-oscillator models, to about 67% calculated with the two Sturmian models

Magnetic moments of triply heavy baryons in quark-diquark model

International Nuclear Information System (INIS)

Thakkar, Kaushal; Majethiya, Ajay; Vinodkumar, P.C.

2016-01-01

Along with the well-established triply flavoured (uuu) and strange (sss) baryons, QCD predicts similar states made up of charm quarks, the triply-charmed baryon, ccc and bottom quarks, the triply-bottom baryon, bbb. Such a state has yet to be observed experimentally. After the observation of the doubly charmed baryon by the SELEX group, it is expected that the triply heavy flavour baryonic state may be in the offing very soon. Though considerable amount of data on the properties of the singly-heavy baryons are available in literature, only sparse attention has been paid to the spectroscopy of double and triple-heavy flavour baryons, perhaps mainly due to the lack of experimental incentives

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.

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.

High-energy manifestations of heavy quarks in axial-vector neutral currents

International Nuclear Information System (INIS)

Kizukuri, Y.; Ohba, I.; Okano, K.; Yamanaka, Y.

1981-01-01

A recent work by Collins, Wilczek, and Zee has attempted to manifest the incompleteness of the decoupling theorem in the axial-vector neutral currents at low energies. In the spirit of their work, we calculate corrections of the axial-vector neutral currents by virtual-heavy-quark exchange in the high-energy e + e - processes and estimate some observable quantities sensitive to virtual-heavy-quark masses which may be compared with experimental data at LEP energies

A quark structure of hadrons and nuclei

International Nuclear Information System (INIS)

Chakrabarty, S.; Deoghuria, S.

1992-08-01

In this review we look into the recent understanding of mesons, baryons and nuclei as few quark bound states within the framework of quantum chromodynamics (QCD). In particular, we have reviewed our understanding of the nature of confining interaction, the spin - dependence of colour forces and the role of non-perturbative effects in the study of quark forces in the potential model approach. We also give a comparative study of results obtained by several potential models with reference to the experimental data. We find that although the Lorentz nature of confinement and the nature of spin-dependent colour forces have been better understood now, only a partial understanding of these problems are obtained so far. Our study reveals that properties of baryons could be explained by the same potential model which successfully describe the mesons. However, the nuclei require chiral symmetry and non-perturbative methods for their description. We also discuss the relation between constituent, current and dynamical quark masses. We conclude that QCD motivated approaches have shown much success in explaining many results on hadronic and nuclear data. (author). 212 refs, 14 tabs

Radiation by a heavy quark in N=4 SYM at strong coupling

CERN Document Server

Hatta, Y; Mueller, A H; Triantafyllopoulos, D N

2011-01-01

Using the AdS/CFT correspondence in the supergravity approximation, we compute the energy density radiated by a heavy quark undergoing some arbitrary motion in the vacuum of the strongly coupled N=4 supersymmetric Yang-Mills theory. We find that this energy is fully generated via backreaction from the near-boundary endpoint of the dual string attached to the heavy quark. Because of that, the energy distribution shows the same space-time localization as the classical radiation that would be produced by the heavy quark at weak coupling. We believe that this and some other unnatural features of our result (like its anisotropy and the presence of regions with negative energy density) are artifacts of the supergravity approximation, which will be corrected after including string fluctuations. For the case where the quark trajectory is bounded, we also compute the radiated power, by integrating the energy density over the surface of a sphere at infinity. For sufficiently large times, we find agreement with a previo...

Energy Lossand Flow of Heavy Quarks in Au+Au Collisions at root-s=200GeV

Energy Technology Data Exchange (ETDEWEB)

Soltz, R; Klay, J; Enokizono, A; Newby, J; Heffner, M; Hartouni, E

2007-02-26

The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3 < p{sub rmT} < 9 GeV/c at midrapidity (|y| < 0.35) from heavy flavor (charm and bottom) decays in Au+Au collisions at {radical}s{sub NN} = 200 GeV. The nuclear modification factor R{sub AA} relative to p+p collisions shows a strong suppression in central Au+Au collisions, indicating substantial energy loss of heavy quarks in the medium produced at RHIC energies. A large azimuthal anisotropy, v{sub 2}, with respect to the reaction plane is observed for 0.5 < p{sub rmT} < 5 GeV/c indicating non-zero heavy flavor elliptic flow. A simultaneous description of R{sub AA}(p{sub rmT}) and v{sub 2}(p{sub rmT}) constrains the existing models of heavy-quark rescattering in strongly interacting matter and provides information on the transport properties of the produced medium. In particular, a viscosity to entropy density ratio close to the conjectured quantum lower bound, i.e. near a perfect fluid, is suggested.

Experimental studies on the heavy quark fragmentation functions

International Nuclear Information System (INIS)

Bethke, S.

1985-07-01

The influence of perturbative QCD gluon radiation and initial state photon radiation on the experimental determination of the heavy quark fragmentation functions is studied in order to extract , the mean of the charm fragmentation function, from the recent measurements of inclusive Dsup(*) production in e + e - annihilation processes. The result is =0.71+-0.014+-0.03, which is scale invariant in the c.m. energy range of 10 GeV to 34 GeV. This result is interpreted in terms of kinematical calculations on heavy quark fragmentation and also compared with results from ν-N-reactions and from investigations of inclusive lepton production in e + e - annihilation. Results of a QCD shower model are in good agreement with the data and offer an alternative description of phenomenological fragmentation functions. (orig.)

Inclusive Decays of Heavy Quarkonium to Light Particles

CERN Document Server

Brambilla, Nora; Pineda-Ruiz, A; Soto, J; Vairo, Antonio; Brambilla, Nora; Eiras, Dolors; Pineda, Antonio; Soto, Joan; Vairo, Antonio

2003-01-01

We derive the imaginary part of the potential NRQCD Hamiltonian up to order 1/m^4, when the typical momentum transfer between the heavy quarks is of the order of Lambda_{QCD} or greater, and the binding energy E much smaller than Lambda_{QCD}. We use this result to calculate the inclusive decay widths into light hadrons, photons and lepton pairs, up to O(mv^3 x (Lambda_{QCD}^2/m^2,E/m)) and O(mv^5) times a short-distance coefficient, for S- and P-wave heavy quarkonium states, respectively. We achieve a large reduction in the number of unknown non-perturbative parameters and, therefore, we obtain new model-independent QCD predictions. All the NRQCD matrix elements relevant to that order are expressed in terms of the wave functions at the origin and six universal non-perturbative parameters. The wave-function dependence factorizes and drops out in the ratio of hadronic and electromagnetic decay widths. The universal non-perturbative parameters are expressed in terms of gluonic field-strength correlators, which ...

On the nonperturbative foundations of the dipole picture

Energy Technology Data Exchange (ETDEWEB)

Ewerz, C. [Milano Univ., INFN, Dipt. di Fisica (Italy); ECT, Villazzano (Trento) (Italy); Nachtmannc, B.O. [Heidelberg Univ., Institut fur Theoretische Physik (Germany)

2005-07-01

Starting from a completely non-perturbative formulation of photon-proton scattering we have identified the assumptions and approximations that are needed in order to obtain the dipole picture at high energies. At the same time we have found corrections to the dipole picture which can become large at small photon virtualities. We consider it as an important task for the future to investigate in detail the validity of the assumptions, the accuracy of the approximations, and the size of the corrections. In our opinion these issues should be addressed in order to put the results obtained in the framework of the dipole picture on solid ground. The framework developed here should be suitable for studying the effects caused by the non-existence of a mass-shell for quarks, and for using non-perturbative quark propagators, obtained for example from Dyson-Schwinger equations or from lattice simulations.

Hadrons of arbitrary spin and heavy quark symmetry

International Nuclear Information System (INIS)

Hussain, F.; Thompson, G.; Koerner, J.G.

1993-11-01

We present a general construction of the spin content of the Bethe-Salpeter amplitudes (covariant wave functions) for heavy hadrons with arbitrary orbital excitations, using representations of l x O(3, 1). These wave functions incorporate the symmetries manifest in the heavy quark limit. In the baryonic sector we clearly differentiate between the Λ and Σ-type excited baryons. We then use the trace formalism to evaluate the weak transitions of ground state heavy hadrons to arbitrary excited heavy hadrons. The contributions of excited states to the Bjorken sum rule are also worked out in detail. (author). 21 refs

Effective potential for heavy quark antiquark bound system

Energy Technology Data Exchange (ETDEWEB)

Barik, B K; Deo, B B

1985-12-01

A heavy quark antiquark potential is suggested connecting asymptotic freedom and quark confinement in a unified way. The ..cap alpha../sub g/(q/sup 2/) calculated using Borel summation technique with three loop agrees with the two loop ..beta..-function up to g/sup 2//4..pi.. -- 1.1 but changes appreciably after g/sup 2//4..pi.. = 1.5. The potential so derived satisfactorily explains the c overlined c and b overlined b spectrum. 13 refs., 4 figures, 3 tables.

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

International Nuclear Information System (INIS)

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

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.)

Chemical Potential Dependence of the Dressed-Quark Propagator from an Effective Quark-Quark Interaction

Institute of Scientific and Technical Information of China (English)

ZONG Hong-Shi; PING Jia-Lun; SUN Wei-Min; CHANG Chao-Hsi; WANG Fan

2002-01-01

We exhibit a method for obtaining the low chemical potential dependence of the dressed quark propagatorfrom an effective quark-quark interaction model. Within this approach we explore the chemical potential dependenceof the dressed-quark propagator, which provides a means of determining the behavior of the chiral and deconfinementorder parameters. A comparison with the results of previous researches is given.

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.

Indirect serarches for very heavy quarks

International Nuclear Information System (INIS)

Bigi, I.I.

1987-03-01

Detailed studies of weak decays can reveal the presence of very massive quanta like heavy top quarks or fourth family quarks. The decay K + → π + ν anti ν and B/sub d/ - anti B/sub d/ mixing are particularly promising fields for such searches. We infer a rather conservative lower limit of 70 GeV on the top mass form recent ARGUS data on B/sub d/ - anti B/sub d/ mixing, near-maximal B 8 - anti B 8 mixing is another consequence. If on the other hand top were detected in Z 0 decays, then the presence of New Physics would be established in B 0 decays. The ratio between tau(B 0 ) and tau(B +- ) is of considerable phenomenological relevance here

Monte Carlo determination of the spin-dependent potentials

International Nuclear Information System (INIS)

Campostrini, M.; Moriarty, K.J.M.; Rebbi, C.

1987-05-01

Calculation of the bound states of heavy quark systems by a Hamiltonian formulation based on an expansion of the interaction into inverse powers of the quark mass is discussed. The potentials for the spin-orbit and spin-spin coupling between quark and antiquark, which are responsible for the fine and hyperfine splittings in heavy quark spectroscopy, are expressed as expectation values of Wilson loop factors with suitable insertions of chromomagnetic or chromoelectric fields. A Monte Carlo simulation has been used to evaluate the expectation values and, from them, the spin-dependent potentials. The Monte Carlo calculation is reported to show a long-range, non-perturbative component in the interaction

Study of heavy quarks production with ALEPH

International Nuclear Information System (INIS)

Perret, P.

1990-05-01

The first data collected by the ALEPH detector at LEP have provided the matter of this study concerning the measure of the partial widths of the Z boson decay into heavy quarks from an analysis of inclusive leptons spectrum. After a presentation of the expected Z decay width into bantib, we explain the phase during which the b quark becomes observable as a beautiful hadron and discuss the present model validity describing this transition by a comparison with the data. Come afterwards the beautiful mesons semileptonic decays description. A more specific work, the possibility of testing the B mesons semileptonic decay model with the D * polarisation measure, is also presented. By fitting the momentum-transverse momentum spectrum of the electrons observed in the hadronic Z decays, we measure the partial widths. We extract Z → bantib, first in an ample dominated by leptons coming from b decays, and then Z → bantib and Z → cantic simultaneously by a global fit of the electron spectrum, including also a determination of the heavy quarks fragmentation parameters in the Peterson framework. We have measured the ratio of the b partial width and the total hadronic width (0.212 ± 0.024) and that of the c (0.182 ± 0.070) in good agreement with the Standard Model. Statistic and systematic errors have comparable values [fr

Proceedings of the Summer institute on particle physics: The top quark and the electroweak interaction

Energy Technology Data Exchange (ETDEWEB)

Burke, D.; Dixon, L.; Leith, D.W.G.S.

1997-01-01

The XXIII SLAC Summer Institute on Particle Physics addressed the physics of the recently discovered top quark, and its connection to the electroweak interaction and to physics beyond the Standard Model. The seven-day school portion of the Institute covered many avenues for studying the top quark, from its direct production at hadron colliders and at future electron-positron colliders, to its virtual effects in precision electroweak quantities, in heavy flavor physics, and in the renormalization of supersymmetric theories, Vertex detectors - critical for identifying the b quark decay products of the top - and Cherenkov techniques for particle identification were also reviewed. The Institute concluded with a three-day topical conference covering recent developments in theory and experiment; this year, the highlights were the CDF and D0 top quark discovery. Also featured were updated precision electroweak measurements from SLC, LEP, and the Tevatron, heavy quark results from these facilities as well as CLEO, and new photoproduction and deep-inelastic scattering data from HERA. Separate abstracts have been submitted to the energy database for articles from this proceedings.

Proceedings of the Summer institute on particle physics: The top quark and the electroweak interaction

International Nuclear Information System (INIS)

Burke, D.; Dixon, L.; Leith, D.W.G.S.

1997-01-01

The XXIII SLAC Summer Institute on Particle Physics addressed the physics of the recently discovered top quark, and its connection to the electroweak interaction and to physics beyond the Standard Model. The seven-day school portion of the Institute covered many avenues for studying the top quark, from its direct production at hadron colliders and at future electron-positron colliders, to its virtual effects in precision electroweak quantities, in heavy flavor physics, and in the renormalization of supersymmetric theories, Vertex detectors - critical for identifying the b quark decay products of the top - and Cherenkov techniques for particle identification were also reviewed. The Institute concluded with a three-day topical conference covering recent developments in theory and experiment; this year, the highlights were the CDF and D0 top quark discovery. Also featured were updated precision electroweak measurements from SLC, LEP, and the Tevatron, heavy quark results from these facilities as well as CLEO, and new photoproduction and deep-inelastic scattering data from HERA. Separate abstracts have been submitted to the energy database for articles from this proceedings

Heavy quark effective theory, interpolating fields and Bethe-Salpeter amplitudes

International Nuclear Information System (INIS)

Hussain, F.; Thomspon, G.

1994-07-01

We use the LSZ reduction theorem and interpolating fields, along with the heavy quark effective theory, to investigate the structure of the Bethe-Salpeter amplitude for heavy hadrons. We show how a simple form of this amplitude, used extensively in heavy hadron decay calculations, follows naturally up to O(1/M) from these field theoretic considerations. (author). 13 refs, 1 tab

Ultra relativistic heavy ions collisions or the search for quark-gluon plasmas

International Nuclear Information System (INIS)

Blaizot, J.P.

1985-03-01

This paper reviews some aspects of the physics of ultra-relativistic heavy ion collisions. The qualitative changes expected in the properties of hadronic matter at high temperature and/or large baryon density are described in terms of simple models. We discuss a scenario giving the space-time evolution of a quark-gluon plasma. Finally we address the difficult question of the possible signatures of the formation of a quark-gluon plasma in heavy ion collisions

Heavy ion collisions, the quark-gluon plasma and antinucleon annihilation

International Nuclear Information System (INIS)

Sarma, Nataraja

1985-01-01

Studies in high energy physics have indicated that nucleon and mesons are composed of quarks confined in bags by the strong colours mediated by gluons. It is reasonably expected that at suitably high baryon density and temperature of the nucleus, these bags of nucleon and mesons fuse into a big bag of quarks or gluons i.e. hadronic matter undergoes transition to a quark-gluon phase. Two techniques to achieve this transition in a laboratory are: (1) collision of two heavy nuclei, and (2) annihilation of antinucleons and antinuclei in nuclear matter. Theoretical studies as well as experimental studies associated with the transition to quark-gluon phase are reviewed. (author)

Heavy-Quark Symmetry Implies Stable Heavy Tetraquark Mesons Q_{i}Q_{j}q[over ¯]_{k}q[over ¯]_{l}.

Science.gov (United States)

Eichten, Estia J; Quigg, Chris

2017-11-17

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_{i}Q_{j}q[over ¯]_{k}q[over ¯]_{l} (subscripts label flavors), where q designates a light quark. By evaluating finite-mass corrections, we predict that double-beauty states composed of bbu[over ¯]d[over ¯], bbu[over ¯]s[over ¯], and bbd[over ¯]s[over ¯] will be stable against strong decays, whereas the double-charm states ccq[over ¯]_{k}q[over ¯]_{l}, mixed beauty+charm states bcq[over ¯]_{k}q[over ¯]_{l}, and heavier bbq[over ¯]_{k}q[over ¯]_{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.

An effective potential for heavy quark antiquark bound system

International Nuclear Information System (INIS)

Barik, B.K.; Deo, B.B.

1985-01-01

A heavy quark antiquark potential is suggested connecting asymptotic freedom and quark confinement in a unified way. The α g (q 2 ) calculated using Borel summation technique with three loop agrees with the two loop β-function up to g 2 /4π ∼ 1.1 but changes appreciably after g 2 /4π = 1.5. The potential so derived satisfactorily explains the c overlined c and b overlined b spectrum. (author)

Heavy quark radiation in NLO+PS POWHEG generators

Energy Technology Data Exchange (ETDEWEB)

Buonocore, Luca; Tramontano, Francesco [Universita di Napoli ' ' Federico II' ' , Napoli (Italy); INFN, Sezione di Napoli, Napoli (Italy); Nason, Paolo [CERN, Theoretical Physics Department, Geneve (Switzerland); INFN, Sezione di Milano-Bicocca, Milano (Italy)

2018-02-15

In this paper we deal with radiation from heavy quarks in the context of next-to-leading order calculations matched to parton shower generators. A new algorithm for radiation from massive quarks is presented that has considerable advantages over the one previously employed. We implement the algorithm in the framework of the POWHEG-BOX, and compare it with the previous one in the case of the hvq generator for bottom production in hadronic collisions, and in the case of the bb4l generator for top production and decay. (orig.)

J/ψ-hadron correlation at LHC energy to study the production mechanism of J/ψ

International Nuclear Information System (INIS)

Alam, Noor; Chattopadhyay, Subhasis

2015-01-01

In high-energy collisions, production of heavy qaurkonium is an important tool to study the interplay between perturbative and non-perturbative QCD dynamics. In nucleus-nucleus collisions, production of heavy quarks from the hard scattering processes follow the perturbative QCD and the subsequent formation of bound states follows the non-perturbative process. Production cross section can therefore be factorized into two factors. The first factor is the production of heavy quark c¯ and an antiquark c¯ from hard collisions of incident particles. In the hard scattering process, participants can be gluon from one nucleon interacting with the gluon from another nucleon or a quark from one nucleon interacting an antiquark from other nucleon via the formation of an intermediate virtual gluon. Contribution of gluon fusion is believed to be higher compared to the quark-antiquark annihilation process. Production of unbound cc¯ pair from the hard scattering process is concerned with the short distance part of the production process in perturbative QCD. The second part is the formation of bound state of cc¯ pair which can be specified by phenomenological model of J/ψ formation

Two-Quark Condensate Changes with Quark Current Mass

International Nuclear Information System (INIS)

Lu Changfang; Lue Xiaofu; Wu Xiaohua; Zhan Yongxin

2009-01-01

Using the Schwinger-Dyson equation and perturbation theory, we calculate the two-quark condensates for the light quarks u, d, strange quark s and a heavy quark c with their current masses respectively. The results show that the two-quark condensate will decrease when the quark mass increases, which hints the chiral symmetry may be restored for the heavy quarks.

The coupling of heavy mesons to the pion on the lattice; Couplage des mesons lourds au pion sur reseau

Energy Technology Data Exchange (ETDEWEB)

Herdoiza, G

2004-04-15

The QCD non-perturbative effects are among the main sources of uncertainty in our present knowledge of the Standard Model phenomenology. I will present some of the methods which can be used to study these effects, and I will particularly treat the case of lattice QCD. Effective theories can be combined to the lattice approach in order to study the chiral and the heavy quark sectors. I will give some examples of how these properties can be successfully applied to the quark flavour phenomenology. The coupling of heavy mesons to the pion is related to a non-perturbative quantity, noted g-bar, which is required to extract physical results from the effective theory combining both chiral and heavy quark symmetry. This coupling is also involved in the study of the form factors appearing in the heavy to light semi-leptonic decays. These heavy meson decays are used to extract some of the CKM matrix elements which are know, up to now, only with large uncertainties. Moreover, the chiral effects of heavy mesons depend on pion loops whose vertices are precisely the coupling g-bar. These are some of the reasons why the theoretical and experimental determination of this coupling is required. I will present the results of its studies on the lattice and I will compare them to those obtained through several other methods. I will therefore describe these different approaches, their limitations and possible improvements, both from the point of view of the method and of its application to the determination of the coupling g-bar. (author)

Evaluation of the spectra of baryons containing two heavy quarks in a bag model

International Nuclear Information System (INIS)

He Daheng; Qian Ke; Ding Yibing; Li Xueqian; Shen Pengnian

2004-01-01

In this work, we evaluate the mass spectra of baryons which consist of two heavy quarks and one light quark in the MIT bag model. The two heavy quarks constitute a heavy scalar or axial-vector diquark. Concretely, we calculate the spectra of vertical bar q(QQ ' )> 1/2 and vertical bar q(QQ ' )> 3/2 where Q and Q ' stand for b and/or c quarks. Especially, for vertical bar q(bc)> 1/2 there can be a mixing between vertical bar q(bc) 0 > 1/2 and vertical bar q(bc) 1 > 1/2 where the subscripts 0 and 1 refer to the spin state of the diquark (bc), the mixing is not calculable in the framework of quantum mechanics as the potential model is employed, but can be evaluated by the quantum field theory. Our numerical results indicate that the mixing is sizable

Matching of heavy-light flavour currents between HQET at order 1/m and QCD. I. Strategy and tree-level study

Energy Technology Data Exchange (ETDEWEB)

Della Morte, Michele [Instituto de Fisica Corpuscular IFIC (CSIC), Paterna (Spain); Dooling, Samantha; Heitger, Jochen [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Hesse, Dirk [Parma Univ. degli Studi (Italy); Simma, Hubert [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Collaboration: ALPHA Collaboration

2013-12-15

We present a strategy how to match the full set of components of the heavy-light axial and vector currents in Heavy Quark Effective Theory (HQET), up to and including 1/m{sub h}-corrections, to QCD. While the ultimate goal is to apply these matching conditions non-perturbatively, in this study we first have implemented them at tree-level, in order to find good choices of the matching observables with small O(1/m{sup 2}{sub h}) contributions. They can later be employed in the non-perturbative matching procedure which is a crucial part of precision HQET computations of semileptonic decay form factors in lattice QCD.

Constituent quarks and multi-strange baryon production in heavy-ion collisions

International Nuclear Information System (INIS)

Sahoo, Raghunath; Behera, Nirbhay K.; Nandi, Basanta K.; Varma, Raghava

2009-01-01

Relativistic heavy-ion collisions aim at creating matter at extreme conditions of energy density and temperature which is governed by the partonic degrees of freedom called Quark-Gluon Plasma (QGP). In the early phase of ultra-relativistic heavy ion collisions, when a hot and dense region is formed in the core of the reaction zone, different quark flavors are produced copiously. The produced matter then undergoes transverse expansion and the produced particles suffer multiple scattering among themselves. The formation of the hadrons from the partonic phase is accomplished through further expansion and cooling of the system

Probing new physics at the LHC: searches for heavy top-like quarks with the ATLAS experiment

CERN Document Server

Succurro, Antonella; Casado Lechuga, María Pilar

Is our Standard Model (SM) of the fundamental particle interactions complete? Apparently, the answer is “no”. Many theories have been proposed to explain what is currently not understood, like the nature of Dark Matter, or the reason why the Higgs boson is so light. Now that the Large Hadron Collider (LHC) at CERN is fully operational, it is possible for experiments like ATLAS to explore very high-energy regimes where new physics can be probed. The work presented in this dissertation consists of two analyses aimed at the discovery (or exclusion) of a signal from a new particle: a quark similar to the top quark (the heaviest particle of the Standard Model) but with a larger mass. This new “top-like” quark could be a simple replica of the SM top quark, just with higher mass, i.e. a chiral fourth-generation up-type quark, or it could have exotic features. The latter hypothesis is particularly interesting as many “beyond-Standard Model” theories predict new heavy so-called vector-like quarks. Both sea...

Analyzing B{sub s} - anti B{sub s} mixing. Non-perturbative contributions to bag parameters from sum rules

Energy Technology Data Exchange (ETDEWEB)

Mannel, T. [Siegen Univ. (Germany). FB 7, Theoretische Physik; Pecjak, B.D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Pivovarov, A.A. [Siegen Univ. (Germany). FB 7, Theoretische Physik]|[Russian Academy of Sciecnes, Moscow (Russian Federation). Inst. for Nuclear Research

2007-03-15

We use QCD sum rules to compute matrix elements of the {delta}B=2 operators appearing in the heavy-quark expansion of the width difference of the B{sub s} mass eigenstates. Our analysis includes the leading-order operators Q and Q{sub S}, as well as the subleading operators R{sub 2} and R{sub 3}, which appear at next-to-leading order in the 1/m{sub b} expansion. We conclude that the violation of the factorization approximation for these matrix elements due to non-perturbative vacuum condensates is as low as 1-2%. (orig.)

Diquark condensation and the quark-quark interaction

International Nuclear Information System (INIS)

Bloch, J. C. R.; Roberts, C. D.; Schmidt, S. M.

1999-01-01

We employ a bispinor gap equation to study superfluidity at nonzero chemical potential, μ≠0, in two- and three-color QCD, exploring the gap's sensitivity to the nature of the quark-quark interaction. The two-color theory, QC 2 D, is an excellent exemplar; the order of truncation of the quark-quark scattering kernel K has no qualitative impact, which allows a straightforward elucidation of the effects of μ when the coupling is strong. In the three-color theory the rainbow-ladder truncation admits diquark bound states, a defect that is eliminated by an improvement of K. The corrected gap equation describes a superfluid phase that is semiquantitatively similar to that obtained using the rainbow truncation. A model study suggests that the width of the superfluid gap and the transition point in QC 2 D provide reliable quantitative estimates of those quantities in QCD. (c) 1999 The American Physical Society

Light-light and heavy-light mesons in the model of QCD string with quarks at the ends

CERN Document Server

Nefediev, A V

2002-01-01

The variational einbein field method is applied to the model of the QCD string with quarks at the ends for the case of light-light and heavy-light mesons. Special attention is payed to the proper string dynamics. The correct string slope of the Regge trajectories is reproduced for light-light states which comes out from the picture of rotating string. Masses of several low-lying orbitally and radially excited states in the D, D_s, B, and B_s meson spectra are calculated and a good agreement with the experimental data as well as with recent lattice calculations is found. The role of the string correction to the interquark interaction is discussed at the example of the identification of D*'(2637) state recently claimed by DELPHI Collaboration. For the heavy-light mesons the standard constants used in Heavy Quark Effective Theory are extracted and compared to the results of other approaches.

Heavy quark jets as technicolour signatures in pp and pantip collisions

International Nuclear Information System (INIS)

Girardi, G.; Sorba, P.

1981-02-01

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

Heavy Flavor Physics in Heavy-Ion Collisions with STAR Heavy Flavor Tracker

International Nuclear Information System (INIS)

Yifei Zhang

2010-01-01

Heavy quarks are a unique tool to probe the strongly interacting matter created in relativistic heavy-ion collisions at RHIC energies. Due to their large mass, energetic heavy quarks are predicted to lose less energy than light quarks by gluon radiation when they traverse a Quark-Gluon Plasma. In contrast, recent measurements of non-photonic electrons from heavy quark decays at high transverse momentum (p T ) show a jet quenching level similar to that of the light hadrons. Heavy quark are produced mainly at early stage in heavy-ion collisions, thus they are proposed to probe the QCD medium and to be sensitive to bulk medium properties. Ultimately, their flow behavior may help establish whether light quarks thermalize. But due to the absence of the measurement of B-mesons and precise measurement of D-mesons, it is difficult to separate bottom and charm contributions experimentally in current non-photonic electron measurements for both spectra and elliptic flow v 2 . Therefore, topological reconstruction of D-mesons and identification of electrons from charm and bottom decays are crucial to understand the heavy flavor production and their in medium properties. The Heavy Flavor Tracker (HFT) is a micro-vertex detector utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precise measurement of charmed and bottom hadrons. We present a study on the open charm nuclear modification factor, elliptic flow v 2 and λ c measurement as well as the measurement of bottom mesons via a semi-leptonic decay. (author)

A new method for computing the quark-gluon vertex

International Nuclear Information System (INIS)

Aguilar, A C

2015-01-01

In this talk we present a new method for determining the nonperturbative quark-gluon vertex, which constitutes a crucial ingredient for a variety of theoretical and phenomenological studies. This new method relies heavily on the exact all-order relation connecting the conventional quark-gluon vertex with the corresponding vertex of the background field method, which is Abelian-like. The longitudinal part of this latter quantity is fixed using the standard gauge technique, whereas the transverse is estimated with the help of the so-called transverse Ward identities. This method allows the approximate determination of the nonperturbative behavior of all twelve form factors comprising the quark-gluon vertex, for arbitrary values of the momenta. Numerical results are presented for the form factors in three special kinematical configurations (soft gluon and quark symmetric limit, zero quark momentum), and compared with the corresponding lattice data. (paper)

Heavy quark production by neutrinos and antineutrinos

International Nuclear Information System (INIS)

Scott, D.M.; Tanaka, K.

1979-01-01

The rate for producing t- and b-quarks in, respectively, neutrino and antineutrino interactions with nucleons are estimated. Experimental quark parton distribution functions, SU(2) x SU(2) x U(1) gauge group mixing angles, and threshold suppression through rescaling are used in the calculation. The ratios to total cross sections of b-quark production by anti nu, R/sub b//sup anti nu/, and t-quark production by ν, R/sub t//sup nu/, are, respectively, R/sub b//sup anti nu/ approximately equal to 10 -4 and R/sub t//sup nu/ approximately equal to 10 -5 for an incident energy of 200 GeV. 13 references

Energy loss effects on heavy quark production in heavy-ion collisions at sq root s = 5.5 A TeV

CERN Document Server

Lin Zi Wei

1999-01-01

We study the effect of energy loss on charm and bottom quarks in high-energy heavy-ion collisions including hadronization, longitudinal expansion and partial thermalization. We consider in detail the detector geometry and single lepton energy cuts of the ALICE and CMS detectors at the Large Hadron Collider (LHC) to show the large suppression of high P sub T heavy quarks and the consequences on their semileptonic decays.

Structure of Nonlocal quark vacuum condensate in non-perturbative QCD vacuum

International Nuclear Information System (INIS)

Xiang Qianfei; Ma Weixing; Zhou Lijuan; Jiang Weizhou

2014-01-01

Based on the Dyson-Schwinger Equations (DSEs) with the rainbow truncation, and Operator Product Expansion, the structure of nonlocal quark vacuum condensate in QCD, described by quark self-energy functions A_f and B_f given usually by the solutions of the DSEs of quark propagator, is predicted numerically. We also calculate the local quark vacuum condensate, quark-gluon mixed local vacuum condensate, and quark virtuality. The self-energy functions A_f and B_f are given by the parameterized quark propagator functions σ_v"f (p"2) and σ_s"f (p"2) of Roberts and Williams, instead of the numerical solutions of the DSEs. Our calculated results are in reasonable agreement with those of QCD sum rules, Lattice QCD calculations, and instanton model predictions, although the resulting local quark vacuum condensate for light quarks, u, d, s, are a little bit larger than those of the above theoretical predictions. We think the differences are caused by model dependence. The larger of strange quark vacuum condensate than u, d quark is due to the s quark mass which is more larger than u, d quark masses. Of course, the Roberts-Williams parameterized quark propagator is an empirical formulism, which approximately describes quark propagation. (authors)

Renormalisation constants of quark bilinears in lattice QCD with four dynamical Wilson quarks

Energy Technology Data Exchange (ETDEWEB)

Blossier, Benoit [CNRS et Paris-Sud 11 Univ., Orsay (France). Lab. de Physique Theorique; Brinet, Mariane [CNRS/IN2P3/UJF, Grenoble (France). Lab. de Physique Subatomique et de Cosmologie; Carrasco, Nuria [Valencia Univ., Burjassot (ES). Dept. de Fisica Teorica and IFC] (and others)

2011-12-15

We present preliminary results of the non-perturbative computation of the RI-MOM renormalization constants in a mass-independent scheme for the action with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our project requires dedicated gauge ensembles with four degenerate sea quark flavours at three lattice spacings and at several values of the standard and twisted quark mass parameters. The RI-MOM renormalization constants are obtained from appropriate O(a) improved estimators extrapolated to the chiral limit. (orig.)

Renormalisation constants of quark bilinears in lattice QCD with four dynamical Wilson quarks

International Nuclear Information System (INIS)

Blossier, Benoit; Brinet, Mariane; Carrasco, Nuria

2011-12-01

We present preliminary results of the non-perturbative computation of the RI-MOM renormalization constants in a mass-independent scheme for the action with Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our project requires dedicated gauge ensembles with four degenerate sea quark flavours at three lattice spacings and at several values of the standard and twisted quark mass parameters. The RI-MOM renormalization constants are obtained from appropriate O(a) improved estimators extrapolated to the chiral limit. (orig.)

Chiral dynamics and heavy quark symmetry in a solvable toy field-theoretic model

International Nuclear Information System (INIS)

Bardeen, W.A.; Hill, C.T.

1994-01-01

We study a solvable QCD-like toy theory, a generalization of the Nambu--Jona-Lasinio model, which implements chiral symmetries of light quarks and heavy quark symmetry. The chiral symmetric and chiral broken phases can be dynamically tuned. This implies a parity-doubled heavy-light meson system, corresponding to a (0 - ,1 - ) multiplet and a (0 + ,1 + ) heavy spin multiplet. Consequently the mass difference of the two multiplets is given by a Goldberger-Treiman relation and g A is found to be small. The Isgur-Wise function ξ(w), the decay constant f B , and other observables are studied

Heavy quark spin symmetry and SU(3)-flavour partners of the X(3872)

Energy Technology Data Exchange (ETDEWEB)

Hidalgo-Duque, C., E-mail: carloshd@ific.uv.es [Instituto de Física Corpuscular (IFIC), Centro Mixto CSIC-Universidad de Valencia, Institutos de Investigación de Paterna, Aptd. 22085, E-46071 Valencia (Spain); Nieves, J. [Instituto de Física Corpuscular (IFIC), Centro Mixto CSIC-Universidad de Valencia, Institutos de Investigación de Paterna, Aptd. 22085, E-46071 Valencia (Spain); Pavón Valderrama, M. [Institut de Physique Nucléaire, Université Paris-Sud, IN2P3/CNRS, F-91406 Orsay Cedex (France)

2013-09-20

In this work, an Effective Field Theory (EFT) incorporating light SU(3)-flavour and heavy quark spin symmetries is used to describe charmed meson–antimeson bound states. At Lowest Order (LO), this means that only contact range interactions among the heavy meson and antimeson fields are involved. Besides, the isospin violating decays of the X(3872) will be used to constrain the interaction between the D and a D{sup ¯⁎} mesons in the isovector channel. Finally, assuming that the X(3915) and Y(4140) resonances are D{sup ⁎}D{sup ¯⁎} and D{sub s}{sup ⁎}D{sup ¯}{sub s}{sup ⁎} molecular states, we can determine the four Low Energy Constants (LECs) of the EFT that appear at LO and, therefore, the full spectrum of molecular states with isospin I=0, 1/2 and 1.

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 how they behave for

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

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

International Nuclear Information System (INIS)

Bertone, Valerio

2013-01-01

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 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 how

Impact of the heavy quark matching scales in PDF fits

Energy Technology Data Exchange (ETDEWEB)

Bertone, V. [VU Univ., Amsterdam (Netherlands). Dept. of Physics and Astronomy; Nikhef Theory Goup, Amsterdam (Netherlands); Britzger, D. [DESY, Hamburg (Germany); Camarda, S. [CERN, Geneva (Switzerland); Collaboration: The xFitter Developers' Team; and others

2017-07-15

We investigate the impact of displaced heavy quark matching scales in a global fit. The heavy quark matching scale μ{sub m} determines at which energy scale μ the QCD theory transitions from N{sub F} to N{sub F}+1 in the Variable Flavor Number Scheme (VFNS) for the evolution of the Parton Distribution Functions (PDFs) and strong coupling α{sub S}(μ). We study the variation of the matching scales, and their impact on a global PDF fit of the combined HERA data. As the choice of the matching scale μ{sub m} effectively is a choice of scheme, this represents a theoretical uncertainty; ideally, we would like to see minimal dependence on this parameter. For the transition across the charm quark (from N{sub F}=3 to 4), we find a large μ{sub m}=μ{sub c} dependence of the global fit χ{sup 2} at NLO, but this is significantly reduced at NNLO. For the transition across the bottom quark (from N{sub F}=4 to 5), we have a reduced μ{sub m}=μ{sub b} dependence of the χ{sup 2} at both NLO and NNLO as compared to the charm. This feature is now implemented in xFitter 2.0.0, an open source QCD fit framework.

Spin content of constituent quarks and one-spin asymmetries in inclusive processes

International Nuclear Information System (INIS)

Troshin, S.M.; Tyurin, N.E.

1995-01-01

A mechanism for one-spin asymmetries observed in inclusive hadron production is considered. The main role belongs to the orbital angular momentum of the quark-antiquark cloud in the internal structure of constituent quarks. The origin of the asymmetries in pion production is a result of retaining this internal angular orbital momentum by the perturbative phase of QCD under transition from the non-perturbative phase is proved. The non-perturbative hadron structure is based on the results of chiral quark models. 33 refs.; 8 figs

New Methods in Non-Perturbative QCD

Energy Technology Data Exchange (ETDEWEB)

Unsal, Mithat [North Carolina State Univ., Raleigh, NC (United States)

2017-01-31

In this work, we investigate the properties of quantum chromodynamics (QCD), by using newly developing mathematics and physics formalisms. Almost all of the mass in the visible universe emerges from a quantum chromodynamics (QCD), which has a completely negligible microscopic mass content. An intimately related issue in QCD is the quark confinement problem. Answers to non-perturbative questions in QCD remained largely elusive despite much effort over the years. It is also believed that the usual perturbation theory is inadequate to address these kinds of problems. Perturbation theory gives a divergent asymptotic series (even when the theory is properly renormalized), and there are non-perturbative phenomena which never appear at any order in perturbation theory. Recently, a fascinating bridge between perturbation theory and non-perturbative effects has been found: a formalism called resurgence theory in mathematics tells us that perturbative data and non-perturbative data are intimately related. Translating this to the language of quantum field theory, it turns out that non-perturbative information is present in a coded form in perturbation theory and it can be decoded. We take advantage of this feature, which is particularly useful to understand some unresolved mysteries of QCD from first principles. In particular, we use: a) Circle compactifications which provide a semi-classical window to study confinement and mass gap problems, and calculable prototypes of the deconfinement phase transition; b) Resurgence theory and transseries which provide a unified framework for perturbative and non-perturbative expansion; c) Analytic continuation of path integrals and Lefschetz thimbles which may be useful to address sign problem in QCD at finite density.

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.)

Study of heavy-flavor quarks produced in association with top-quark pairs at $\\sqrt{s}$ = 7 TeV using the ATLAS detector

CERN Document Server

Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; 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; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; 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; 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; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Astbury, Alan; Atkinson, Markus; Auerbach, Benjamin; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagnaia, Paolo; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Sarah; Balek, Petr; Balli, Fabrice; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; 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; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; 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, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; 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; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; 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; Bittner, Bernhard; Black, Curtis; Black, James; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blazek, Tomas; Bloch, Ingo; Blocker, Craig; Blocki, Jacek; Blum, Walter; Blumenschein, Ulrike; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Boddy, Christopher Richard; Boehler, Michael; Boek, Jennifer; Boek, Thorsten Tobias; Boelaert, Nele; Bogaerts, Joannes Andreas; Bogdanchikov, Alexander; Bogouch, Andrei; Bohm, Christian; Bohm, Jan; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Bolnet, Nayanka Myriam; Bomben, Marco; Bona, Marcella; Boonekamp, Maarten; Bordoni, Stefania; Borer, Claudia; Borisov, Anatoly; Borissov, Guennadi; Borjanovic, Iris; Borri, Marcello; Borroni, Sara; Bortfeldt, Jonathan; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boterenbrood, Hendrik; Bouchami, Jihene; Boudreau, Joseph; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boutouil, Sara; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozovic-Jelisavcic, Ivanka; Bracinik, Juraj; Branchini, Paolo; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Brazzale, Simone Federico; Brelier, Bertrand; Bremer, Johan; Brendlinger, Kurt; Brenner, Richard; Bressler, Shikma; Bristow, Timothy Michael; Britton, Dave; Brochu, Frederic; Brock, Ian; Brock, Raymond; Broggi, Francesco; Bromberg, Carl; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, Timothy; Brooks, William; Brown, Gareth; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Brunet, Sylvie; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Bryngemark, Lene; Buanes, Trygve; Buat, Quentin; Bucci, Francesca; Buchanan, James; Buchholz, Peter; Buckingham, Ryan; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Budick, Burton; Bugge, Lars; Bulekov, Oleg; Bundock, Aaron Colin; Bunse, Moritz; Buran, Torleiv; Burckhart, Helfried; Burdin, Sergey; Burgess, Thomas; Burke, Stephen; Busato, Emmanuel; Büscher, Volker; Bussey, Peter; Buszello, Claus-Peter; Butler, Bart; Butler, John; Buttar, Craig; Butterworth, Jonathan; Buttinger, William; Byszewski, Marcin; Cabrera Urbán, Susana; Caforio, Davide; Cakir, Orhan; Calafiura, Paolo; Calderini, Giovanni; Calfayan, Philippe; Calkins, Robert; Caloba, Luiz; Caloi, Rita; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarri, Paolo; Cameron, David; Caminada, Lea Michaela; Caminal Armadans, Roger; Campana, Simone; Campanelli, Mario; Canale, Vincenzo; Canelli, Florencia; Canepa, Anadi; Cantero, Josu; Cantrill, Robert; Cao, Tingting; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capriotti, Daniele; Capua, Marcella; Caputo, Regina; Cardarelli, Roberto; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Sascha; Carquin, Edson; Carrillo-Montoya, German D; Carter, Antony; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Cascella, Michele; Caso, Carlo; Castaneda-Miranda, Elizabeth; Castelli, Angelantonio; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Cataldi, Gabriella; Catastini, Pierluigi; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Cattani, Giordano; Caughron, Seth; Cavaliere, Viviana; Cavalleri, Pietro; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Cerio, Benjamin; Santiago Cerqueira, Augusto; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cervelli, Alberto; Cetin, Serkant Ali; Chafaq, Aziz; Chakraborty, Dhiman; Chalupkova, Ina; Chan, Kevin; Chang, Philip; Chapleau, Bertrand; Chapman, John Derek; Chapman, John Wehrley; Charlton, Dave; Chavda, Vikash; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Shenjian; Chen, Xin; Chen, Yujiao; Cheng, Yangyang; Cheplakov, Alexander; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Cheung, Sing-Leung; Chevalier, Laurent; Chiefari, Giovanni; Chikovani, Leila; Childers, John Taylor; Chilingarov, Alexandre; Chiodini, Gabriele; Chisholm, Andrew; Chislett, Rebecca Thalatta; Chitan, Adrian; Chizhov, Mihail; Choudalakis, Georgios; Chouridou, Sofia; Chow, Bonnie Kar Bo; Christidi, Ilektra-Athanasia; Christov, Asen; Chromek-Burckhart, Doris; Chu, Ming-Lee; Chudoba, Jiri; Ciapetti, Guido; Ciftci, Abbas Kenan; Ciftci, Rena; Cinca, Diane; Cindro, Vladimir; Ciocio, Alessandra; Cirilli, Manuela; Cirkovic, Predrag; Citron, Zvi Hirsh; Citterio, Mauro; Ciubancan, Mihai; Clark, Allan G; Clark, Philip James; Clarke, Robert; Clemens, Jean-Claude; Clement, Benoit; Clement, Christophe; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Coffey, Laurel; Cogan, Joshua Godfrey; Coggeshall, James; Colas, Jacques; Cole, Stephen; Colijn, Auke-Pieter; Collins, Neil; Collins-Tooth, Christopher; Collot, Johann; Colombo, Tommaso; Colon, German; Compostella, Gabriele; Conde Muiño, Patricia; Coniavitis, Elias; Conidi, Maria Chiara; Consonni, Sofia Maria; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conti, Geraldine; Conventi, Francesco; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Cooper-Smith, Neil; Copic, Katherine; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Corso-Radu, Alina; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Côté, David; Cottin, Giovanna; Courneyea, Lorraine; Cowan, Glen; Cox, Brian; Cranmer, Kyle; Crépé-Renaudin, Sabine; Crescioli, Francesco; Cristinziani, Markus; Crosetti, Giovanni; Cuciuc, Constantin-Mihai; Cuenca Almenar, Cristóbal; Cuhadar Donszelmann, Tulay; Cummings, Jane; Curatolo, Maria; Curtis, Chris; Cuthbert, Cameron; Czirr, Hendrik; Czodrowski, Patrick; Czyczula, Zofia; D'Auria, Saverio; D'Onofrio, Monica; D'Orazio, Alessia; Da Cunha Sargedas De Sousa, Mario Jose; Da Via, Cinzia; Dabrowski, Wladyslaw; Dafinca, Alexandru; Dai, Tiesheng; Dallaire, Frederick; Dallapiccola, Carlo; Dam, Mogens; Damiani, Daniel; Daniells, Andrew Christopher; Danielsson, Hans Olof; Dao, Valerio; Darbo, Giovanni; Darlea, Georgiana Lavinia; Darmora, Smita; Dassoulas, James; Davey, Will; Davidek, Tomas; Davidson, Nadia; Davies, Eleanor; Davies, Merlin; Davignon, Olivier; Davison, Adam; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Castro, Stefano; De Cecco, Sandro; de Graat, Julien; De Groot, Nicolo; de Jong, Paul; De La Taille, Christophe; De la Torre, Hector; De Lorenzi, Francesco; De Nooij, Lucie; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; De Zorzi, Guido; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dechenaux, Benjamin; Dedovich, Dmitri; Degenhardt, James; Del Peso, Jose; Del Prete, Tarcisio; Delemontex, Thomas; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delsart, Pierre-Antoine; Deluca, Carolina; Demers, Sarah; Demichev, Mikhail; Demirkoz, Bilge; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Deviveiros, Pier-Olivier; Dewhurst, Alastair; DeWilde, Burton; Dhaliwal, Saminder; Dhullipudi, Ramasudhakar; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Donato, Camilla; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Luise, Silvestro; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Diaz, Marco Aurelio; Diehl, Edward; Dietrich, Janet; Dietzsch, Thorsten; Diglio, Sara; Dindar Yagci, Kamile; Dingfelder, Jochen; Dinut, Florin; Dionisi, Carlo; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; Barros do Vale, Maria Aline; Do Valle Wemans, André; Doan, Thi Kieu Oanh; Dobos, Daniel; Dobson, Ellie; Dodd, Jeremy; Doglioni, Caterina; Doherty, Tom; Dohmae, Takeshi; Doi, Yoshikuni; Dolejsi, Jiri; Dolezal, Zdenek; Dolgoshein, Boris; Donadelli, Marisilvia; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dos Anjos, Andre; Dotti, Andrea; Dova, Maria-Teresa; Doyle, Tony; Dressnandt, Nandor; Dris, Manolis; Dubbert, Jörg; Dube, Sourabh; Dubreuil, Emmanuelle; Duchovni, Ehud; Duckeck, Guenter; Duda, Dominik; Dudarev, Alexey; Dudziak, Fanny; Duerdoth, Ian; Duflot, Laurent; Dufour, Marc-Andre; Duguid, Liam; Dührssen, Michael; Dunford, Monica; Duran Yildiz, Hatice; Düren, Michael; Duxfield, Robert; Dwuznik, Michal; Ebenstein, William; Ebke, Johannes; Eckweiler, Sebastian; Edson, William; Edwards, Clive; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Eisenhandler, Eric; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Ellis, Katherine; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Enari, Yuji; Engelmann, Roderich; Engl, Albert; Epp, Brigitte; Erdmann, Johannes; Ereditato, Antonio; Eriksson, Daniel; Ernst, Jesse; Ernst, Michael; Ernwein, Jean; Errede, Deborah; Errede, Steven; Ertel, Eugen; Escalier, Marc; Esch, Hendrik; Escobar, Carlos; Espinal Curull, Xavier; Esposito, Bellisario; Etienne, Francois; Etienvre, Anne-Isabelle; Etzion, Erez; Evangelakou, Despoina; Evans, Hal; Fabbri, Laura; Fabre, Caroline; Facini, Gabriel; Fakhrutdinov, Rinat; Falciano, Speranza; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farley, Jason; Farooque, Trisha; Farrell, Steven; Farrington, Sinead; Farthouat, Philippe; Fassi, Farida; Fassnacht, Patrick; Fassouliotis, Dimitrios; Fatholahzadeh, Baharak; Favareto, Andrea; Fayard, Louis; Federic, Pavol; Fedin, Oleg; Fedorko, Wojciech; Fehling-Kaschek, Mirjam; Feligioni, Lorenzo; Feng, Cunfeng; Feng, Eric; Feng, Haolu; Fenyuk, Alexander; Ferencei, Jozef; Fernando, Waruna; Ferrag, Samir; Ferrando, James; Ferrara, Valentina; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filthaut, Frank; Fincke-Keeler, Margret; Finelli, Kevin Daniel; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Julia; Fisher, Matthew; Fitzgerald, Eric Andrew; Flechl, Martin; Fleck, Ivor; Fleischmann, Philipp; Fleischmann, Sebastian; Fletcher, Gareth Thomas; Fletcher, Gregory; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Florez Bustos, Andres Carlos; Flowerdew, Michael; Fonseca Martin, Teresa; Formica, Andrea; Forti, Alessandra; Fortin, Dominique; Fournier, Daniel; Fowler, Andrew; Fox, Harald; Francavilla, Paolo; Franchini, Matteo; Franchino, Silvia; Francis, David; Franklin, Melissa; Franz, Sebastien; Fraternali, Marco; Fratina, Sasa; French, Sky; Friedrich, Conrad; Friedrich, Felix; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fulsom, Bryan Gregory; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gabrielli, Andrea; Gadatsch, Stefan; Gadfort, Thomas; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Galhardo, Bruno; Gallas, Elizabeth; Gallo, Valentina Santina; Gallop, Bruce; Gallus, Petr; Gan, KK; Gandrajula, Reddy Pratap; Gao, Yongsheng; Gaponenko, Andrei; Garay Walls, Francisca; Garberson, Ford; García, Carmen; García Navarro, José Enrique; Garcia-Sciveres, Maurice; Gardner, Robert; Garelli, Nicoletta; Garonne, Vincent; Gatti, Claudio; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gauzzi, Paolo; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gazis, Evangelos; Ge, Peng; Gecse, Zoltan; Gee, Norman; Geerts, Daniël Alphonsus Adrianus; Geich-Gimbel, Christoph; Gellerstedt, Karl; Gemme, Claudia; Gemmell, Alistair; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerbaudo, Davide; Gerlach, Peter; Gershon, Avi; Geweniger, Christoph; Ghazlane, Hamid; Ghodbane, Nabil; Giacobbe, Benedetto; Giagu, Stefano; Giangiobbe, Vincent; Gianotti, Fabiola; Gibbard, Bruce; Gibson, Adam; Gibson, Stephen; Gilchriese, Murdock; Gillam, Thomas; Gillberg, Dag; Gillman, Tony; Gingrich, Douglas; Giokaris, Nikos; Giordani, MarioPaolo; Giordano, Raffaele; Giorgi, Francesco Michelangelo; Giovannini, Paola; Giraud, Pierre-Francois; Giugni, Danilo; Giuliani, Claudia; Giunta, Michele; Gjelsten, Børge Kile; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glazov, Alexandre; Glonti, George; Goddard, Jack Robert; Godfrey, Jennifer; Godlewski, Jan; Goebel, Martin; Goeringer, Christian; Goldfarb, Steven; Golling, Tobias; Golubkov, Dmitry; Gomes, Agostinho; Gomez Fajardo, Luz Stella; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez Silva, Laura; Gonzalez-Sevilla, Sergio; Goodson, Jeremiah Jet; Goossens, Luc; Göpfert, Thomas; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorfine, Grant; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Goshaw, Alfred; Gössling, Claus; Gostkin, Mikhail Ivanovitch; Gough Eschrich, Ivo; Gouighri, Mohamed; Goujdami, Driss; Goulette, Marc Phillippe; Goussiou, Anna; Goy, Corinne; Gozpinar, Serdar; Graber, Lars; Grabowska-Bold, Iwona; Grafström, Per; Grahn, Karl-Johan; Gramstad, Eirik; Grancagnolo, Francesco; Grancagnolo, Sergio; Grassi, Valerio; Gratchev, Vadim; Gray, Heather; Gray, Julia Ann; Graziani, Enrico; Grebenyuk, Oleg; Greenshaw, Timothy; Greenwood, Zeno Dixon; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grigalashvili, Nugzar; Grillo, Alexander; Grimm, Kathryn; Grinstein, Sebastian; Gris, Philippe Luc Yves; Grishkevich, Yaroslav; Grivaz, Jean-Francois; Grohs, Johannes Philipp; Grohsjean, Alexander; Gross, Eilam; Grosse-Knetter, Joern; Groth-Jensen, Jacob; Grybel, Kai; Guest, Daniel; Gueta, Orel; Guicheney, Christophe; Guido, Elisa; Guillemin, Thibault; Guindon, Stefan; Gul, Umar; Gunther, Jaroslav; Guo, Bin; Guo, Jun; Gutierrez, Phillip; Guttman, Nir; Gutzwiller, Olivier; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haas, Stefan; Haber, Carl; Hadavand, Haleh Khani; Haefner, Petra; Hajduk, Zbigniew; Hakobyan, Hrachya; Hall, David; Halladjian, Garabed; Hamacher, Klaus; Hamal, Petr; Hamano, Kenji; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Handel, Carsten; Hanke, Paul; Hansen, John Renner; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hansson, Per; Hara, Kazuhiko; Hard, Andrew; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Hartert, Jochen; Hartjes, Fred; Haruyama, Tomiyoshi; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hassani, Samira; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hayakawa, Takashi; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hayward, Helen; Haywood, Stephen; Head, Simon; Heck, Tobias; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heinemann, Beate; Heisterkamp, Simon; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, James; Henderson, Robert; Henke, Michael; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Hensel, Carsten; Herbert, Geoffrey Henry; Medina Hernandez, Carlos; Hernández Jiménez, Yesenia; Herrberg, Ruth; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Hickling, Robert; Higón-Rodriguez, Emilio; Hill, John; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hofmann, Julia Isabell; Hohlfeld, Marc; Holmgren, Sven-Olof; Holzbauer, Jenny; Hong, Tae Min; Hooft van Huysduynen, Loek; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hrabovsky, Miroslav; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huettmann, Antje; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hülsing, Tobias Alexander; Hurwitz, Martina; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibbotson, Michael; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Idarraga, John; Iengo, Paolo; Igonkina, Olga; Ikegami, Yoichi; Ikematsu, Katsumasa; Ikeno, Masahiro; Iliadis, Dimitrios; Ilic, Nikolina; Ince, Tayfun; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jamin, David Olivier; Jana, Dilip; Jansen, Eric; Jansen, Hendrik; Janssen, Jens; Jantsch, Andreas; Janus, Michel; Jared, Richard; Jarlskog, Göran; Jeanty, Laura; Jeng, Geng-yuan; Jen-La Plante, Imai; Jennens, David; Jenni, Peter; Jeske, Carl; Jež, Pavel; Jézéquel, Stéphane; Jha, Manoj Kumar; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Shan; Jinnouchi, Osamu; Joergensen, Morten Dam; Joffe, David; Johansen, Marianne; Johansson, Erik; Johansson, Per; Johnert, Sebastian; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Joram, Christian; Jorge, Pedro; Joshi, Kiran Daniel; Jovicevic, Jelena; Jovin, Tatjana; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Jussel, Patrick; Juste Rozas, Aurelio; Kabana, Sonja; Kaci, Mohammed; Kaczmarska, Anna; Kadlecik, Peter; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kajomovitz, Enrique; Kalinin, Sergey; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kar, Deepak; Karagounis, Michael; Karakostas, Konstantinos; Karnevskiy, Mikhail; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Yousuke; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kazama, Shingo; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Keener, Paul; Kehoe, Robert; Keil, Markus; Keller, John; Keoshkerian, Houry; Kepka, Oldrich; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharchenko, Dmitri; Khodinov, Alexander; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hyeon Jin; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; King, Samuel Burton; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kitamura, Takumi; Kittelmann, Thomas; Kiuchi, Kenji; Kladiva, Eduard; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klemetti, Miika; Klier, Amit; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Klous, Sander; Kluge, Eike-Erik; Kluit, Peter; Kluth, Stefan; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Ko, Byeong Rok; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Koenig, Sebastian; Koetsveld, Folkert; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohn, Fabian; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolanoski, Hermann; Koletsou, Iro; Koll, James; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Köneke, Karsten; König, Adriaan; Kono, Takanori; Kononov, Anatoly; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kopeliansky, Revital; Koperny, Stefan; Köpke, Lutz; Kopp, Anna Katharina; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kravchenko, Anton; Kreiss, Sven; Kretzschmar, Jan; Kreutzfeldt, Kristof; Krieger, Nina; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kruse, Mark; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Thorsten; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kuna, Marine; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurata, Masakazu; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwee, Regina; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Lablak, Said; Lacasta, Carlos; Lacava, Francesco; Lacey, James; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laier, Heiko; Laisne, Emmanuel; Lambourne, Luke; Lampen, Caleb; Lampl, Walter; Lançon, Eric; Landgraf, Ulrich; Landon, Murrough; Lang, Valerie Susanne; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Lanza, Agostino; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Larner, Aimee; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Laycock, Paul; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Menedeu, Eve; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Michel; Legendre, Marie; Legger, Federica; Leggett, Charles; Lehmacher, Marc; Lehmann Miotto, Giovanna; Leister, Andrew Gerard; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Lendermann, Victor; Leney, Katharine; Lenz, Tatiana; Lenzen, Georg; Lenzi, Bruno; Leonhardt, Kathrin; Leontsinis, Stefanos; Lepold, Florian; Leroy, Claude; Lessard, Jean-Raphael; Lester, Christopher; Lester, Christopher Michael; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bing; Li, Bo; Li, Haifeng; Li, Ho Ling; Li, Shu; Li, Xuefei; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lie, Ki; Liebal, Jessica; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Lindquist, Brian Edward; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Lisovyi, Mykhailo; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Dong; Liu, Jianbei; Liu, Kun; Liu, Lulu; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lo Sterzo, Francesco; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loevschall-Jensen, Ask Emil; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Lombardo, Vincenzo Paolo; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Losty, Michael; Lou, XinChou; Lounis, Abdenour; Loureiro, Karina; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Ludwig, Dörthe; Ludwig, Inga; Ludwig, Jens; Luehring, Frederick; Lukas, Wolfgang; Luminari, Lamberto; Lund, Esben; Lundberg, Björn; Lundberg, Johan; Lundberg, Olof; Lund-Jensen, Bengt; Lundquist, Johan; Lungwitz, Matthias; Lynn, David; Lysak, Roman; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Macina, Daniela; Mackeprang, Rasmus; Madar, Romain; Madaras, Ronald; Maddocks, Harvey Jonathan; Mader, Wolfgang; Madsen, Alexander; Maeno, Mayuko; Maeno, Tadashi; Magnoni, Luca; Magradze, Erekle; Mahboubi, Kambiz; Mahlstedt, Joern; Mahmoud, Sara; Mahout, Gilles; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Malecki, Piotr; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mamuzic, Judita; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Manfredini, Alessandro; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany Andreina; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mantifel, Rodger; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marroquim, Fernando; Marshall, Zach; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian; Martin, Brian Thomas; Martin, Jean-Pierre; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martinez, Homero; Martinez, Mario; Martin-Haugh, Stewart; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matsunaga, Hiroyuki; Matsushita, Takashi; Mättig, Peter; Mättig, Stefan; Mattravers, Carly; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; Mazini, Rachid; Mazur, Michael; Mazzaferro, Luca; Mazzanti, Marcello; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Mechtel, Markus; Medinnis, Mike; Meehan, Samuel; Meera-Lebbai, Razzak; Meguro, Tatsuma; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meineck, Christian; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mendoza Navas, Luis; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Meric, Nicolas; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer, Joerg; Michal, Sebastien; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Miller, Robert; Mills, Bill; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Mitrevski, Jovan; Mitsou, Vasiliki A; Mitsui, Shingo; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Moeller, Victoria; Mohapatra, Soumya; Mohr, Wolfgang; Moles-Valls, Regina; Molfetas, Angelos; Mönig, Klaus; Monini, Caterina; Monk, James; Monnier, Emmanuel; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Möser, Nicolas; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Mudd, Richard; Mueller, Felix; Mueller, James; Mueller, Klemens; Mueller, Thibaut; Mueller, Timo; Muenstermann, Daniel; Müller, Thomas; Munwes, Yonathan; Murillo Quijada, Javier Alberto; Murray, Bill; Mussche, Ido; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nackenhorst, Olaf; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagai, Yoshikazu; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Namasivayam, Harisankar; Nanava, Gizo; Napier, Austin; Narayan, Rohin; Nash, Michael; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Negrini, Matteo; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neusiedl, Andrea; Neves, Ricardo; Nevski, Pavel; Newcomer, Mitchel; Newman, Paul; Nguyen, Duong Hai; Nguyen Thi Hong, Van; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Niedercorn, Francois; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsen, Henrik; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Norberg, Scarlet; Nordberg, Markus; Novakova, Jana; Nozaki, Mitsuaki; Nozka, Libor; Nuncio-Quiroz, Adriana-Elizabeth; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; O'Brien, Brendan Joseph; O'Neil, Dugan; O'Shea, Val; Oakes, Louise Beth; Oakham, Gerald; Oberlack, Horst; Ocariz, Jose; Ochi, Atsuhiko; Ochoa, Ines; Oda, Susumu; Odaka, Shigeru; Odier, Jerome; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohshima, Takayoshi; Okamura, Wataru; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira, Miguel Alfonso; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Osuna, Carlos; Otero y Garzon, Gustavo; Ottersbach, John; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Simon; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganis, Efstathios; Pahl, Christoph; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Paleari, Chiara; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Panduro Vazquez, William; Pani, Priscilla; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Papadelis, Aras; Papadopoulou, Theodora; Paramonov, Alexander; Paredes Hernandez, Daniela; Park, Woochun; Parker, Michael Andrew; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pashapour, Shabnaz; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pearce, James; Pedersen, Maiken; Pedraza Lopez, Sebastian; Pedraza Morales, Maria Isabel; Peleganchuk, Sergey; Pelikan, Daniel; Peng, Haiping; Penning, Bjoern; Penson, Alexander; Penwell, John; Perez Cavalcanti, Tiago; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Perrodo, Pascal; Peshekhonov, Vladimir; Peters, Krisztian; Peters, Yvonne; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petschull, Dennis; Petteni, Michele; Pezoa, Raquel; Phan, Anna; Phillips, Peter William; Piacquadio, Giacinto; Pianori, Elisabetta; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Pingel, Almut; Pinto, Belmiro; Pizio, Caterina; Pleier, Marc-Andre; Pleskot, Vojtech; Plotnikova, Elena; Plucinski, Pawel; Poblaguev, Andrei; Poddar, Sahill; Podlyski, Fabrice; Poettgen, Ruth; Poggioli, Luc; Pohl, David-leon; Pohl, Martin; Polesello, Giacomo; Policicchio, Antonio; Polifka, Richard; Polini, Alessandro; Polychronakos, Venetios; Pomeroy, Daniel; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Pospelov, Guennady; Pospisil, Stanislav; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Pretzl, Klaus Peter; Price, Darren; Price, Joe; Price, Lawrence; Prieur, Damien; Primavera, Margherita; Proissl, Manuel; Prokofiev, Kirill; Prokoshin, Fedor; Protopapadaki, Eftychia-sofia; Protopopescu, Serban; Proudfoot, James; Prudent, Xavier; Przybycien, Mariusz; Przysiezniak, Helenka; Psoroulas, Serena; Ptacek, Elizabeth; Pueschel, Elisa; Puldon, David; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Quadt, Arnulf; Quarrie, David; Quayle, William; Quilty, Donnchadha; Raas, Marcel; Radeka, Veljko; Radescu, Voica; Radloff, Peter; Ragusa, Francesco; Rahal, Ghita; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Randrianarivony, Koloina; Rangel-Smith, Camila; Rao, Kanury; Rauscher, Felix; Rave, Tobias Christian; Ravenscroft, Thomas; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Reinsch, Andreas; Reisinger, Ingo; Relich, Matthew; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rieck, Patrick; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Rios, Ryan Randy; Ritsch, Elmar; Riu, Imma; Rivoltella, Giancesare; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Rocha de Lima, Jose Guilherme; Roda, Chiara; Roda Dos Santos, Denis; Roe, Adam; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romeo, Gaston; Romero Adam, Elena; Rompotis, Nikolaos; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosenbaum, Gabriel; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rosselet, Laurent; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexandre; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Ruckstuhl, Nicole; Rud, Viacheslav; Rudolph, Christian; Rudolph, Matthew Scott; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rumyantsev, Leonid; Rurikova, Zuzana; Rusakovich, Nikolai; Ruschke, Alexander; Rutherfoord, John; Ruthmann, Nils; Ruzicka, Pavel; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Saddique, Asif; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salek, David; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Sanchez, Arturo; Sánchez, Javier; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sansoni, Andrea; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Santoyo Castillo, Itzebelt; Sapp, Kevin; Saraiva, João; Sarangi, Tapas; Sarkisyan-Grinbaum, Edward; Sarrazin, Bjorn; Sarri, Francesca; Sartisohn, Georg; Sasaki, Osamu; Sasaki, Yuichi; Sasao, Noboru; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Sauvan, Jean-Baptiste; Savard, Pierre; Savinov, Vladimir; Savu, Dan Octavian; Sawyer, Craig; Sawyer, Lee; Saxon, David; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schaelicke, Andreas; Schaepe, Steffen; Schaetzel, Sebastian; Schäfer, Uli; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R. Dean; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schillo, Christian; Schioppa, Marco; Schlenker, Stefan; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Christopher; Schmitt, Sebastian; Schneider, Basil; Schnellbach, Yan Jie; Schnoor, Ulrike; Schoeffel, Laurent; Schoening, Andre; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schroeder, Christian; Schroer, Nicolai; Schultens, Martin Johannes; Schultes, Joachim; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwartzman, Ariel; Schwegler, Philipp; Schwemling, Philippe; Schwienhorst, Reinhard; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Sciacca, Gianfranco; Scifo, Estelle; Sciolla, Gabriella; Scott, Bill; Scutti, Federico; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekula, Stephen; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellers, Graham; Seman, Michal; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Serre, Thomas; Seuster, Rolf; Severini, Horst; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Sherwood, Peter; Shimizu, Shima; Shimojima, Makoto; Shin, Taeksu; Shiyakova, Mariya; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simoniello, Rosa; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smestad, Lillian; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Kenway; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snidero, Giacomo; Snow, Joel; Snyder, Scott; Sobie, Randall; Sodomka, Jaromir; Soffer, Abner; Soh, Dart-yin; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Solovyev, Victor; Soni, Nitesh; Sood, Alexander; Sopko, Vit; Sopko, Bruno; Sosebee, Mark; Soualah, Rachik; Soueid, Paul; Soukharev, Andrey; South, David; Spagnolo, Stefania; Spanò, Francesco; Spighi, Roberto; Spigo, Giancarlo; Spiwoks, Ralf; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stanitzki, Marcel Michael; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Staude, Arnold; Stavina, Pavel; Steele, Genevieve; Steinbach, Peter; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoebe, Michael; Stoerig, Kathrin; Stoicea, Gabriel; Stonjek, Stefan; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strang, Michael; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Strong, John; Stroynowski, Ryszard; Stugu, Bjarne; Stumer, Iuliu; Stupak, John; Sturm, Philipp; Styles, Nicholas Adam; Su, Dong; Subramania, Halasya Siva; Subramaniam, Rajivalochan; Succurro, Antonella; Sugaya, Yorihito; Suhr, Chad; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Suzuki, Yuta; Svatos, Michal; Swedish, Stephen; Swiatlowski, Maximilian; Sykora, Ivan; Sykora, Tomas; Ta, Duc; Tackmann, Kerstin; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tam, Jason; Tamsett, Matthew; Tan, Kong Guan; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tapprogge, Stefan; Tardif, Dominique; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tassi, Enrico; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teinturier, Marthe; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Testa, Marianna; Teuscher, Richard; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thoma, Sascha; Thomas, Juergen; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thong, Wai Meng; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tic, Tomáš; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tiouchichine, Elodie; Tipton, Paul; Tisserant, Sylvain; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tomlinson, Lee; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tonoyan, Arshak; Topfel, Cyril; Topilin, Nikolai; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Tran, Huong Lan; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alessandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Triplett, Nathan; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trovatelli, Monica; True, Patrick; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiakiris, Menelaos; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsung, Jieh-Wen; Tsuno, Soshi; Tsybychev, Dmitri; Tua, Alan; Tudorache, Alexandra; Tudorache, Valentina; Tuggle, Joseph; Tuna, Alexander Naip; Turala, Michal; Turecek, Daniel; Turk Cakir, Ilkay; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Tzanakos, George; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ughetto, Michael; Ugland, Maren; Uhlenbrock, Mathias; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Ungaro, Francesca; Unno, Yoshinobu; Urbaniec, Dustin; Urquijo, Phillip; Usai, Giulio; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Vahsen, Sven; Valencic, Nika; Valentinetti, Sara; Valero, Alberto; Valery, Loic; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Berg, Richard; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; Van Der Leeuw, Robin; van der Poel, Egge; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; Van Nieuwkoop, Jacobus; van Vulpen, Ivo; Vanadia, Marco; Vandelli, Wainer; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Vari, Riccardo; Varnes, Erich; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vassilakopoulos, Vassilios; Vazeille, Francois; Vazquez Schroeder, Tamara; Veloso, Filipe; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinogradov, Vladimir; Virzi, Joseph; Vitells, Ofer; Viti, Michele; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; Volpini, Giovanni; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vos, Marcel; Voss, Rudiger; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Vykydal, Zdenek; Wagner, Wolfgang; Wagner, Peter; Wahlen, Helmut; Wahrmund, Sebastian; Wakabayashi, Jun; Walch, Shannon; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Walsh, Brian; Wang, Chiho; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Kuhan; Wang, Rui; Wang, Song-Ming; Wang, Tan; Wang, Xiaoxiao; Warburton, Andreas; Ward, Patricia; Wardrope, David Robert; Warsinsky, Markus; Washbrook, Andrew; Wasicki, Christoph; Watanabe, Ippei; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Anthony; Waugh, Ben; Weber, Michele; Webster, Jordan S; Weidberg, Anthony; Weigell, Philipp; Weingarten, Jens; Weiser, Christian; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Werth, Michael; Wessels, Martin; Wetter, Jeffrey; Whalen, Kathleen; White, Andrew; White, Martin; White, Sebastian; Whitehead, Samuel Robert; Whiteson, Daniel; Whittington, Denver; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilhelm, Ivan; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Eric; Williams, Hugh; Williams, Sarah; Willis, William; Willocq, Stephane; Wilson, John; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wittig, Tobias; Wittkowski, Josephine; Wollstadt, Simon Jakob; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wong, Wei-Cheng; Wooden, Gemma; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wraight, Kenneth; Wright, Michael; Wrona, Bozydar; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xie, Song; Xu, Chao; Xu, Da; Xu, Lailin; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamaguchi, Yohei; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamauchi, Katsuya; Yamazaki, Takayuki; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Hongtao; Yang, Un-Ki; Yang, Yi; Yang, Zhaoyu; Yanush, Serguei; Yao, Liwen; Yasu, Yoshiji; Yatsenko, Elena; Yau Wong, Kaven Henry; Ye, Jingbo; Ye, Shuwei; Yen, Andy L; Yildirim, Eda; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Rikutaro; Yoshihara, Keisuke; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, Dantong; Yu, David Ren-Hwa; Yu, Jaehoon; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Zabinski, Bartlomiej; Zaidan, Remi; Zaitsev, Alexander; Zambito, Stefano; Zanello, Lucia; Zanzi, Daniele; Zaytsev, Alexander; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zenin, Oleg; Ženiš, Tibor; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhang, Dongliang; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Lei; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Ning; Zhou, Yue; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhuravlov, Vadym; Zibell, Andre; Zieminska, Daria; Zimin, Nikolai; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Zinonos, Zinonas; Ziolkowski, Michael; Zitoun, Robert; Živković, Lidija; Zmouchko, Viatcheslav; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zutshi, Vishnu; Zwalinski, Lukasz

2014-04-21

Using a sample of dilepton top-quark pair ($t\\bar{t}$) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of $t\\bar{t}+b+X$ and $t\\bar{t}$+c+X, collectively referred to as $t\\bar{t}$ + HF. The data set used corresponds to an integrated luminosity of 4.7  $fb{−1}$ of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF (b or c) quarks in the $t\\bar{t}$ sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b quarks from the $t\\bar{t}$ decays and the third to additional HF production. The dominant background to $t\\bar{t}$ + HF in this sample is $t\\bar{t}$+jet events in which a light-flavor jet is misidentified as a heavy-flavor jet. To determine the heavy- and light-flavor content of the additional b-tagged jets, a fit to the vertex mass distribution of b-tagged jets in t...

Dual Ginzburg-Landau theory and quark nuclear physics

International Nuclear Information System (INIS)

Toki, Hiroshi

1999-01-01

The elementary building blocks of matter are quarks. Hence, it is fundamental to describe hadrons and nuclei in terms of quarks and gluons, the subject of which is called Quark Nuclear Physics. The quark-dynamics is described by Quantum Chromodynamics (QCD). Our interest is the non-perturbative aspect of QCD as confinement, chiral symmetry breaking, hadronization etc. We introduce the dual Ginzburg-Landau theory (DGL), where the color monopole fields and their condensation is the QCD vacuum, play essential roles in describing these non-perturbative phenomena. We emphasize its connection to QCD through the use of the Abelian gauge. We apply the DGL theory to various observables. We discuss then the connection of the monopole fields with instantons, which are the classical solutions of the non-Abelian gauge theory and connect through the tunneling process QCD vacuum with different winding numbers. (author)

Aspects of the heavy-quark photoproduction in the semihard approach

International Nuclear Information System (INIS)

Mariotto, C. Brenner; Ducati, M.B. Gay; Machado, M.V.T.

2002-01-01

In this contribution we report on the calculations of heavy-quark photoproduction using the K p erpendicular to-factorization (semihard) approach, emphasizing the results obtained with the phenomenological saturation model. (author)

The heavy quark form factors at two loops

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Behring, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Teilchenphysik und Kosmologie; Bluemlein, J.; Freitas, A. de; Marquard, P.; Rana, N. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Falcioni, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Nikhef, Amsterdam (Netherlands). Theory Group

2017-12-15

We compute the two-loop QCD corrections to the heavy quark form factors in case of the vector, axial-vector, scalar and pseudo-scalar currents up to second order in the dimensional parameter ε=(4-D)/2. These terms are required in the renormalization of the higher order corrections to these form factors.

Effective interactions from q-deformed quark fields

International Nuclear Information System (INIS)

Timoteo, V. S.; Lima, C. L.

2007-01-01

From the mass term for q-deformed quark fields, we obtain effective contact interactions of the NJL type. The parameters of the model that maps a system of non-interacting deformed fields into quarks interacting via NJL contact terms is discussed

A new parametric equation of state and quark stars

International Nuclear Information System (INIS)

Na Xuesen; Xu Renxin

2011-01-01

It is still a matter of debate to understand the equation of state of cold matter with supra-nuclear density in compact stars because of unknown non-perturbative strong interaction between quarks. Nevertheless, it is speculated from an astrophysical view point that quark clusters could form in cold quark matter due to strong coupling at realistic baryon densities. Although it is hard to calculate this conjectured matter from first principles, one can expect that the inter-cluster interaction will share some general features with the nucleon- nucleon interaction successfully depicted by various models. We adopt a two-Gaussian component soft-core potential with these general features and show that quark clusters can form stable simple cubic crystal structure if we assume that the wave function of quark clusters have a Gaussian form. With this parametrization, the Tolman-Oppenheimer-Volkoff equation is solved with reasonably constrained parameter space to give mass-radius relations of crystalline solid quark stars. With baryon number densities truncated at 2n 0 at surface and the range of the interaction fixed at 2 fm we can reproduce similar mass-radius relations to that obtained with bag model equations of state. The maximum mass ranges from ∼ 0.5 solar mass to approx.> 3 solar mass . The recently measured high pulsar mass (approx.> 2 solar mass ) is then used to constrain the parameters of this simple interaction potential. (authors)

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.

Heavy-light mesons in lattice HQET and QCD

International Nuclear Information System (INIS)

Guazzini, D.

2007-12-01

We present a study of a combination of HQET and relativistic QCD to extract the b-quark mass and the B s -meson decay constant from lattice quenched simulations. We start from a small volume, where one can directly simulate the b-quark, and compute the connection to a large volume, where finite size effects are negligible, through a finite size technique. The latter consists of steps extrapolated to the continuum limit, where the b-region is reached through interpolations guided by the effective theory. With the lattice spacing given in terms of the Sommer's scale r 0 and the experimental B s and K masses, we get the final results for the renormalization group invariant mass M b =6.88(10) GeV, translating into anti m b (anti m b )=4.42(6) GeV in the MS scheme, and f B s =191(6) MeV for the decay constant. A renormalization condition for the chromo-magnetic operator, responsible, at leading order in the heavy quark mass expansion of HQET, for the mass splitting between the pseudoscalar and the vector channel in mesonic heavy-light bound states, is provided in terms of lattice correlations functions which well suits a non-perturbative computation involving a large range of renormalization scales and no valence quarks. The two-loop expression of the corresponding anomalous dimension in the Schroedinger functional (SF) scheme is computed starting from results in the literature; it requires a one-loop calculation in the SF scheme with a non-vanishing background field. The cutoff effects affecting the scale evolution of the renormalization factors are studied at one-loop order, and confirmed by non-perturbative quenched computations to be negligible for the numerical precision achievable at present. (orig.)

Heavy-light mesons in lattice HQET and QCD

Energy Technology Data Exchange (ETDEWEB)

Guazzini, D.

2007-12-15

We present a study of a combination of HQET and relativistic QCD to extract the b-quark mass and the B{sub s}-meson decay constant from lattice quenched simulations. We start from a small volume, where one can directly simulate the b-quark, and compute the connection to a large volume, where finite size effects are negligible, through a finite size technique. The latter consists of steps extrapolated to the continuum limit, where the b-region is reached through interpolations guided by the effective theory. With the lattice spacing given in terms of the Sommer's scale r{sub 0} and the experimental B{sub s} and K masses, we get the final results for the renormalization group invariant mass M{sub b}=6.88(10) GeV, translating into anti m{sub b}(anti m{sub b})=4.42(6) GeV in the MS scheme, and f{sub B{sub s}}=191(6) MeV for the decay constant. A renormalization condition for the chromo-magnetic operator, responsible, at leading order in the heavy quark mass expansion of HQET, for the mass splitting between the pseudoscalar and the vector channel in mesonic heavy-light bound states, is provided in terms of lattice correlations functions which well suits a non-perturbative computation involving a large range of renormalization scales and no valence quarks. The two-loop expression of the corresponding anomalous dimension in the Schroedinger functional (SF) scheme is computed starting from results in the literature; it requires a one-loop calculation in the SF scheme with a non-vanishing background field. The cutoff effects affecting the scale evolution of the renormalization factors are studied at one-loop order, and confirmed by non-perturbative quenched computations to be negligible for the numerical precision achievable at present. (orig.)

Color sextet quarks and new high-energy interactions

International Nuclear Information System (INIS)

White, A.R.; Kang, Kyungsik

1992-01-01

We review the implications of adding a flavor doublet of color sextet quarks to QCD. Theoretical attractions include -- ''minimal'' dynamical symmetry breaking of the electroweak interaction, solution of the Strong CP problem via the ''heavy axion'' η 6 , and Critical Pomeron Scaling at asymptotic energies. Related experimental phenomena, which there may be evidence for, include -- production of the η 6 at LEP, large cross-sections for W + W - and Z o Z o pairs and very high energy jets in hadron colliders, and a hadronic threshold above which high-energy ''exotic'' diffractive processes appear in Cosmic Ray events

Quarkonium states in an anisotropic quark-gluon plasma

Energy Technology Data Exchange (ETDEWEB)

Guo Yun

2009-09-10

In this work we study the properties of quarkonium states in a quark-gluon plasma which, due to expansion and non-zero viscosity, exhibits a local anisotropy in momentum space. We determine the hard-loop resummed gluon propagator in an anisotropic QCD plasma in general linear gauges and define a potential between heavy quarks from the Fourier transform of its static limit. This potential which arises due to one-gluon exchange describes the force between a quark and anti-quark at short distances. It is closer to the vacuum potential as compared to the isotropic Debye screened potential which indicates the reduced screening in an anisotropic QCD plasma. In addition, angular dependence appears in the potential; we find that there is stronger attraction on distance scales on the order of the inverse Debye mass for quark pairs aligned along the direction of anisotropy than for transverse alignment. The potential at long distances, however, is non-perturbative and modeled as a QCD string which is screened at the same scale as the Coulomb field. At asymptotic separation the potential energy is non-zero and inversely proportional to the temperature. With a phenomenological potential model which incorporates the different behaviors at short and long distances, we solve the three-dimensional Schroedinger equation. Our numerical results show that quarkonium binding is stronger at non-vanishing viscosity and expansion rate, and that the anisotropy leads to polarization of the P-wave states. Furthermore, we determine viscosity corrections to the imaginary part of the heavy-quark potential in the weak-coupling hard-loop approximation. The imaginary part is found to be smaller (in magnitude) than at vanishing viscosity. This implies a smaller decay width of quarkonium bound states in an anisotropic plasma. (orig.)

Quarkonium states in an anisotropic quark-gluon plasma

International Nuclear Information System (INIS)

Guo Yun

2009-01-01

In this work we study the properties of quarkonium states in a quark-gluon plasma which, due to expansion and non-zero viscosity, exhibits a local anisotropy in momentum space. We determine the hard-loop resummed gluon propagator in an anisotropic QCD plasma in general linear gauges and define a potential between heavy quarks from the Fourier transform of its static limit. This potential which arises due to one-gluon exchange describes the force between a quark and anti-quark at short distances. It is closer to the vacuum potential as compared to the isotropic Debye screened potential which indicates the reduced screening in an anisotropic QCD plasma. In addition, angular dependence appears in the potential; we find that there is stronger attraction on distance scales on the order of the inverse Debye mass for quark pairs aligned along the direction of anisotropy than for transverse alignment. The potential at long distances, however, is non-perturbative and modeled as a QCD string which is screened at the same scale as the Coulomb field. At asymptotic separation the potential energy is non-zero and inversely proportional to the temperature. With a phenomenological potential model which incorporates the different behaviors at short and long distances, we solve the three-dimensional Schroedinger equation. Our numerical results show that quarkonium binding is stronger at non-vanishing viscosity and expansion rate, and that the anisotropy leads to polarization of the P-wave states. Furthermore, we determine viscosity corrections to the imaginary part of the heavy-quark potential in the weak-coupling hard-loop approximation. The imaginary part is found to be smaller (in magnitude) than at vanishing viscosity. This implies a smaller decay width of quarkonium bound states in an anisotropic plasma. (orig.)

Heavy-quark production in deep-inelastic scattering

International Nuclear Information System (INIS)

Alekhin, Sergey; Bluemlein, Johannes; Moch, Sven-Olaf; Hamburg Univ.

2013-08-01

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 c (m c )=1.24±0.03(exp) +0.03 -0.02 (scale) +0.00 -0.07 (th) and m c (m c )=1.15±0.04(exp) +0.04 -0.00 (scale) are determined at NNLO and NLO, respectively. The values of m 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.

Heavy quark-antiquark pair production by double pomeron exchange in pp and AA collisions on the CMS

International Nuclear Information System (INIS)

Agababyan, N.M.; Ajrapetyan, M.G.; Galoyan, A.S.; Zarubin, P.I.; Malakhov, A.I.; Melkumov, G.L.; Chatrchyan, S.A.; Enkovskij, L.L.

1998-01-01

Events in hadronic and nuclear collisions, which contain a central dijet system together with the two quasi-elastically scattered beam particles are usually described by double pomeron scattering. We investigate these processes for central production of heavy quark-antiquark pairs on the LHC by using the CMS detector. The total and differential cross sections with the formation of cc bar and bb bar pairs for various interactions assumed to a realization on the LHC are evaluated. It is especially marked that this process can be used for investigations of various aspects of low-x physics, for instance, for a research of the gluon and quark distributions in the pomerons, the factorization hypothesis, coherent interaction of nuclei, nuclei shadowing and so on

Vectorlike quarks and heavy colored bosons at the LHC

Science.gov (United States)

Deandrea, A.; Iyer, A. M.

2018-03-01

We investigate the production of heavy colored scalars and vectors and their relevance at the LHC for the study of vectorlike quarks (T ). These colored states (C ) are present in a large number of extensions of the standard model, in particular, in composite models and in extradimensional models. Assuming that these bosonic states are heavier than the vectorlike quarks (VLQ), we consider their production through the process p p →C →t T . Large QCD production cross sections for C enable us to probe heavier masses for the VLQ, thereby allowing us to put stronger limits on the vectorlike quarks which are produced in their decay chain. We adopt a universal analysis strategy by including leptons under the classification of "jets," thereby limiting the bias towards a specific combination of final state. We also study the possibility of disentangling these scenarios from supersymmetric extensions of the standard model by using simple discriminants based on jet multiplicity and missing energy. We demonstrate that a simple set of cuts is sufficient to disentangle the VLQ signal from the backgrounds. In models with a moderate B .R .(C →T t ) , the analysis enables one to get a hint of VLQ masses as heavy as 3 TeV.

Constituent quarks and enhancement of multi-strange baryons in heavy-ion collisions

International Nuclear Information System (INIS)

Behera, Nirbhay Kumar; Nandi, Basanta Kumar; Sahoo, Raghunath

2011-01-01

Heavy-ion collisions at relativistic energies aim to produce a state of matter which is governed by partonic degrees of freedom, known as Quark-Gluon Plasma (QGP). In the central rapidity region, strangeness enhancement has been proposed as a potential signature of QGP. It has been observed that a quark participant scaling of the multi-strange baryon production and also a strangeness scaling of the enhancement. This confirms that the partonic degrees of freedom is playing a major role in the particle production mechanism and may therefore significantly determine the formation of QGP in heavy ion collisions

New results on CLEO's heavy quarks - bottom and charm

International Nuclear Information System (INIS)

Menary, S.

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 heavyclose quotes quarks - bottom and charm. I will describe new results in the B meson sector including the first observation of exclusive b → ulv decays, upper limits on gluonic penguin decay rates, and precise measurements of semileptonic and hadronic b → c branching fractions. The charmed hadron results that are discussed include the observation of isospin violation in D s * + decays, an update on measurements of the D s + decay constant, and the observation of a new excited Ξ c charmed baryon. These measurements have had a large impact on our understanding of heavy quark physics

Impact of the heavy-quark matching scales in PDF fits

Energy Technology Data Exchange (ETDEWEB)

Bertone, V. [VU University, Department of Physics and Astronomy, Amsterdam (Netherlands); Nikhef Theory Group Science Park 105, Amsterdam (Netherlands); Britzger, D.; Geiser, A.; Glazov, A.; Zenaiev, O. [DESY, Hamburg (Germany); Camarda, S. [CERN, Geneva (Switzerland); Cooper-Sarkar, A.; Giuli, F. [University of Oxford (United Kingdom); Godat, E.; Lyonnet, F.; Olness, F. [SMU Physics, Dallas, TX (United States); Kusina, A. [Universite Grenoble Alpes, CNRS/IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Polish Academy of Sciences, Institute of Nuclear Physics, Krakow (Poland); Luszczak, A. [T. Kosciuszko Cracow University of Technology, Krakow (Poland); Placakyte, R. [Universitaet Hamburg, Institut fuer Theoretische Physik, Hamburg (Germany); Radescu, V. [DESY, Hamburg (Germany); CERN, Geneva (Switzerland); Schienbein, I. [Universite Grenoble Alpes, CNRS/IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Collaboration: The xFitter Developers' Team

2017-12-15

We investigate the impact of displaced heavy-quark matching scales in a global fit. The heavy-quark matching scale μ{sub m} determines at which energy scale μ the QCD theory transitions from N{sub F} to N{sub F} + 1 in the variable flavor number scheme (VFNS) for the evolution of the parton distribution functions (PDFs) and strong coupling α{sub S}(μ). We study the variation of the matching scales, and their impact on a global PDF fit of the combined HERA data. As the choice of the matching scale μ{sub m} effectively is a choice of scheme, this represents a theoretical uncertainty; ideally, we would like to see minimal dependence on this parameter. For the transition across the charm quark (from N{sub F} = 3 to 4), we find a large μ{sub m} = μ{sub c} dependence of the global fit χ{sup 2} at NLO, but this is significantly reduced at NNLO. For the transition across the bottom quark (from N{sub F} = 4 to 5), we have a reduced μ{sub m} = μ{sub b} dependence of the χ{sup 2} at both NLO and NNLO as compared to the charm. This feature is now implemented in xFitter 2.0.0, an open source QCD fit framework. (orig.)

Strong Interactions, (De)coherence and Quarkonia

CERN Document Server

Bellucci, Stefano; Tiwari, Bhupendra Nath

2011-01-01

Quarkonia are the central objects to explore the non-perturbative nature of non-abelian gauge theories. We describe the confinement-deconfinement phases for heavy quarkonia in a hot QCD medium and thereby the statistical nature of the inter-quark forces. In the sense of one-loop quantum effects, we propose that the "quantum" nature of quark matters follows directly from the thermodynamic consideration of Richardson potential. Thereby we gain an understanding of the formation of hot and dense states of quark gluon plasma matter in heavy ion collisions and the early universe. In the case of the non-abelian theory, the consideration of the Sudhakov form factor turns out to be an efficient tool for soft gluons. In the limit of the Block-Nordsieck resummation, the strong coupling obtained from the Sudhakov form factor yields the statistical nature of hadronic bound states, e.g. kaons and Ds particles.

Experimental Highlights: Heavy Quark Physics in Heavy-Ion Collisions at RHIC

Directory of Open Access Journals (Sweden)

Nouicer Rachid

2017-01-01

Full Text Available The discovery at RHIC of large high-pT suppression and flow of electrons from heavy quarks flavors have altered our view of the hot and dense matter formed in central Au + Au collisions at √sNN = 200 GeV. These results suggest a large energy loss and flow of heavy quarks in the hot, dense matter. In recent years, the RHIC experiments upgraded the detectors; (1 PHENIX Collaboration installed silicon vertex tracker (VTX at midrapidity region and forward silicon vertex tracker (FVTX at the forward rapidity region, and (2 STAR Collaboration installed the heavy flavor tracker (HFT and the muon telescope detector (MTD both at the mid-rapidity region. The PHENIX experiments established measurements of ψ (1S and ψ (2S production as a function of system size, p + p, p + Al, p + Au, and 3He + Au collisions at √sNN = 200 GeV. In p/3He + A collisions at forward rapidity, we observe no difference in the ψ (2S /ψ (1S ratio relative to p + p collisions. At backward rapidity, where the comoving particle density is higher, we find that the ψ (2S is preferentially suppressed by a factor of two. STAR Collaboration presents the first J/ ψ measurements in the di-muon decay channel in Au + Au at √sNN = 200 GeV at mid-rapidity. We observe a clear J/ψ RAA suppression and qualitatively well described by transport models, including dissociation and regeneration simultaneously.

A quark-antiquark potential from a superconducting model of confinement

Directory of Open Access Journals (Sweden)

J.W. Alcock

1983-10-01

Full Text Available The Landau-Ginzburg phenomenological theory of superconductivity is used as a model of flux confinement. A monopole pair of sources is included to simulate a quark-antiquark system. The interaction energy is found in the static approximation appropriate for heavy quark systems, and equated with the interquark potential. This potential is compared with other suggested phenomenological potentials and succeeds in reproducing heavy quark spectra.

Dark matter admixed strange quark stars in the Starobinsky model

Science.gov (United States)

Lopes, Ilídio; Panotopoulos, Grigoris

2018-01-01

We compute the mass-to-radius profiles for dark matter admixed strange quark stars in the Starobinsky model of modified gravity. For quark matter, we assume the MIT bag model, while self-interacting dark matter inside the star is modeled as a Bose-Einstein condensate with a polytropic equation of state. We numerically integrate the structure equations in the Einstein frame, adopting the two-fluid formalism, and we treat the curvature correction term nonperturbatively. The effects on the properties of the stars of the amount of dark matter as well as the higher curvature term are investigated. We find that strange quark stars (in agreement with current observational constraints) with the highest masses are equally affected by dark matter and modified gravity.

Qualitative quark confinement

International Nuclear Information System (INIS)

Jackson, T.L.

1976-01-01

The infrared limit in asymptotically free non-abelian gauge theories using recently developed non-perturbative methods which allow derivation of zero momentum theorems for Green's functions and vertices is described. These low-energy theorems are compared to the infrared behavior predicted from the renormalization group equation when the existence of an infrared fixed point is assumed. A set of objects is exhibited whose low energy theorems violate the scaling behavior predicted by the renormalization group. This shows that the assumed fixed point cannot exist and that in the Landau gauge the effective charge becomes infinite in the infrared. Qualitatively this implies that as an attempt is made to separate elementary quanta the interaction between the quanta becomes arbitrarily strong. This indicates at least that the theories studied are capable of color confinement. Results are true only for theories with large numbers of quarks. This opens the possibility that large numbers of quarks are actually necessary for confinement

Vector Susceptibility of QCD Vacuum from an Effective Quark-Quark Interaction

Institute of Scientific and Technical Information of China (English)

ZONG Hong-Shi; QI Shi; CHEN Wei; WU Xiao-Hua

2003-01-01

.A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is given.

Nonperturbative volume reduction of large-N QCD with adjoint fermions

International Nuclear Information System (INIS)

Bringoltz, Barak; Sharpe, Stephen R.

2009-01-01

We use nonperturbative lattice techniques to study the volume-reduced 'Eguchi-Kawai' version of four-dimensional large-N QCD with a single adjoint Dirac fermion. We explore the phase diagram of this single-site theory in the space of quark mass and gauge coupling using Wilson fermions for a number of colors in the range 8≤N≤15. Our evidence suggests that these values of N are large enough to determine the nature of the phase diagram for N→∞. We identify the region in the parameter space where the (Z N ) 4 center symmetry is intact. According to previous theoretical work using the orbifolding paradigm, and assuming that translation invariance is not spontaneously broken in the infinite-volume theory, in this region volume reduction holds: the single-site and infinite-volume theories become equivalent when N→∞. We find strong evidence that this region includes both light and heavy quarks (with masses that are at the cutoff scale), and our results are consistent with this region extending toward the continuum limit. We also compare the action density and the eigenvalue density of the overlap Dirac operator in the fundamental representation with those obtained in large-N pure-gauge theory.

Heavy quark condensates from dynamically borken flavour symmetry

International Nuclear Information System (INIS)

Elliott, T.; King, S.F.

1992-01-01

We study the dynamics of top quark condensation induced by gauge interactions resulting from a broken flavour symmetry. The gap equation in dressed ladder approximation is solved numerically to obtain directly the top quark mass. The new high energy dynamics reduces the prediction of m t somewhat, but the usual problems of m t being too large and fine tuning remain. In order to solve these problems we extend our discussion to include fourth generation quark condensates. (orig.)

Improved lattice fermion action for heavy quarks

International Nuclear Information System (INIS)

Cho, Yong-Gwi; Hashimoto, Shoji; Jüttner, Andreas; Kaneko, Takashi; Marinkovic, Marina; Noaki, Jun-Ichi; Tsang, Justus Tobias

2015-01-01

We develop an improved lattice action for heavy quarks based on Brillouin-type fermions, that have excellent energy-momentum dispersion relation. The leading discretization errors of O(a) and O(a"2) are eliminated at tree-level. We carry out a scaling study of this improved Brillouin fermion action on quenched lattices by calculating the charmonium energy-momentum dispersion relation and hyperfine splitting. We present a comparison to standard Wilson fermions and domain-wall fermions.

Spin-dependent hadro- and photoproduction of heavy quarks at next-to-leading order of QCD

International Nuclear Information System (INIS)

Riedl, Johann

2014-01-01

In this thesis, we have studied heavy quark hadro- and photoproduction in detail and examined the possibilities of using heavy quark production for the extraction of the polarised parton distribution functions. All calculations are performed at O(α s 3 ) and O(αα s 2 ) accuracy, respectively, and theoretical uncertainties due to the choice of scales μ f,r and the heavy quark mass m Q have been discussed in detail. Based on our theoretical results we have presented detailed phenomenological studies for the existing PHENIX and STAR experiments at BNL-RHIC and the COMPASS experiment at CERN. Predictions have been made for possible future experiments at a low-energy antiproton-proton collider at GSI-FAIR, a proton-proton collider at J-PARC and an upcoming high-energy electron-ion collider (EIC).

Diquark condensate and quark interaction with instanton liquid

International Nuclear Information System (INIS)

Zinov'ev, G.M.; Molodtsov, S.V.

2003-01-01

The interaction of light quarks and instanton liquid is analyzed at finite density of quark/baryon matter and in the phase of nonzero values of diquark (color) condensate. It is shown that instanton liquid perturbation produced by such an interaction results in an essential increase of the critical value of quark chemical potential μ c which provokes the perceptible increase of quark matter density around the expected onset of the color superconductivity phase [ru

Static spin-dependent forces between heavy quarks in the classical approximation to dual QCD

International Nuclear Information System (INIS)

Baker, M.; Ball, J.S.; Zachariasen, F.

1991-01-01

We compute the static spin-dependent forces V S (R) (proportional to σ 1 ·σ 2 ) and V T (R) (proportional to 3σ 1 ·Rσ 2 ·R-σ 1 ·σ 2 ) between two quarks separated by R. This is done by treating the (weak) spin-dependent effects as a perturbation on the spin-independent potentials and fields computed earlier for dual QCD. What results is a definite prediction for the heavy-quark potentials which are similar to, but different in form from, those used in phenomenological treatments. Calculations of the masses and splittings of heavy-quark states using our potentials will provide a further test of the dual superconductor picture of QCD

Quarks for hadrons and leptons

International Nuclear Information System (INIS)

Lopes, J.L.

1975-01-01

The simplest, naive, model for a unified description of leptons and hadrons consists in postulating, besides the usual quarks p, n, lambda a fourth quark, with very heavy mass and very high binding to pairs like anti p n and anti p lambda. In a SU(4) scheme the fourth quark has a quantum number charm which may be taken as proportional to the lepton number. Muons would be distinguished from electrons by the occurence of a lambda-quark instead of a n-quark in their structure. The forces among these quarks would have to be such as to give leptons an almost point-like structure at the experimentally known energies as well as absence of strong interactions at these energies. However, one would expect the display of strong interactions by leptons at extremely high energies [pt

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 $t$...

Heavy quark pair production in polarized photon-photon collisions

International Nuclear Information System (INIS)

Jikia, G.; Tkabladze, A.

2000-04-01

We present the cross sections of the heavy quark-antiquark pair production in polarized photon photon collision for the general case of photon polarizations. The numerical results for top-antitop production cross sections together with production asymmetries are obtained for linearly polarized photon-photon collisions, including QCD radiative corrections. (orig.)

Asymmetries in heavy quark pair and dijet production at an EIC

Energy Technology Data Exchange (ETDEWEB)

Boer, Daniël [Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Mulders, Piet J. [Nikhef and Department of Physics and Astronomy, VU University Amsterdam,De Boelelaan 1081, NL-1081 HV Amsterdam (Netherlands); Pisano, Cristian [Dipartimento di Fisica, Università di Pavia,via Bassi 6, I-27100 Pavia (Italy); INFN Sezione di Pavia,via Bassi 6, I-27100 Pavia (Italy); Zhou, Jian [School of physics, Key Laboratory of Particle Physics and Particle Irradiation (MOE),Shandong University,Jinan, Shandong 250100 (China); Nikhef and Department of Physics and Astronomy, VU University Amsterdam,De Boelelaan 1081, NL-1081 HV Amsterdam (Netherlands)

2016-08-01

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 pair and dijet production at a future Electron-Ion Collider.

Excited State Contributions to the Heavy Baryon Fragmentation Functions in a Quark-Diquark Model

CERN Document Server

Adamov, A D; Goldstein, Gary R.

2001-01-01

Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. The resulting $\\Lambda_b$ production rate and polarization at LEP energies are in agreement with experiment. The $\\Lambda_c$ and $\\Xi_c$ functions are also obtained. The spin independent $f_1(z)$ is compared to data. The integrated values for production rates agree with the data.

Weak leptonic decay of light and heavy pseudoscalar mesons in an independent quark model

International Nuclear Information System (INIS)

Barik, N.; Dash, P.C.

1993-01-01

Weak leptonic decays of light and heavy pseudoscalar mesons are studied in a field-theoretic framework based on the independent quark model with a scalar-vector harmonic potential. Defining the quark-antiquark momentum distribution amplitude obtainable from the bound quark eigenmodes of the model with the assumption of a strong correlation between quark-antiquark momenta inside the decaying meson in its rest frame, we derive the partial decay width with correct kinematical factors from which we extract an expression for the pseudoscalar decay constants f M . Using the model parameters determined from earlier studies in the light-flavor sector and heavy-quark masses m c and m b from the hyperfine splitting of (D * ,D) and (B * ,B), we calculate the pseudoscalar decay constants. We find that while (f π ,f K )≡(138,157 MeV); (f D ,f Ds )≡(161,205 MeV), (f B ,f Bs )≡(122,154 MeV), and f Bc =221 MeV. We also obtain the partial decay widths and branching ratios for some kinematically allowed weak leptonic decay processes

Heavy baryons as polarimeters at colliders

Energy Technology Data Exchange (ETDEWEB)

Galanti, Mario [Department of Physics and Astronomy, University of Rochester,Rochester, NY 14627-0171 (United States); Giammanco, Andrea [Centre for Cosmology, Particle Physics and Phenomenology, Université catholique de Louvain,B-1348 Louvain-la-Neuve (Belgium); National Institute of Chemical Physics and Biophysics,10143 Tallinn (Estonia); Grossman, Yuval [Laboratory for Elementary-Particle Physics, Cornell University,Ithaca, NY 14853 (United States); Kats, Yevgeny; Stamou, Emmanuel [Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Rehovot 7610001 (Israel); Zupan, Jure [Department of Physics, University of Cincinnati,Cincinnati, OH 45221 (United States)

2015-11-10

In new-physics processes that produce b or c jets, a measurement of the initial b or c-quark polarization could provide crucial information about the structure of the new physics. In the heavy-quark limit, the b and c-quark polarizations are preserved in the lightest baryons they hadronize into, Λ{sub b} and Λ{sub c}, respectively. We revisit the prediction for the polarization retention after the hadronization process and extend it to the case of transverse polarization. We show how ATLAS and CMS can measure the b-quark polarization using semileptonic Λ{sub b} decays, and the c-quark polarization using Λ{sub c}{sup +}→pK{sup −}π{sup +} decays. For calibrating both measurements we suggest to use tt̄ samples in which these polarizations can be measured with precision of order 10% using 100 fb{sup −1} of data in Run 2 of the LHC. Measurements of the transverse polarization in QCD events at ATLAS, CMS and LHCb are motivated as well. The proposed measurements give access to nonperturbative QCD parameters relevant to the dynamics of the hadronization process.

Heavy quark masses in the continuum limit of quenched Lattice QCD

International Nuclear Information System (INIS)

De Divitiis, G.M.; Guagnelli, M.; Palombi, F.; Petronzio, R.; Tantalo, N.

2003-01-01

We compute charm and bottom quark masses in the quenched approximation and in the continuum limit of lattice QCD. We make use of a step scaling method, previously introduced to deal with two scale problems, that allows to take the continuum limit of the lattice data. We determine the RGI quark masses and make the connection to the MS-bar scheme. The continuum extrapolation gives us a value m b RGI =6.73(16) GeV for the b-quark and m c RGI =1.681(36) GeV for the c-quark, corresponding, respectively, to m b MS-bar (m b MS-bar =4.33(10) GeV and m c MS-bar (m c MS-bar =1.319(28) GeV. The latter result, in agreement with current estimates, is for us a check of the method. Using our results on the heavy quark masses we compute the mass of the B c meson, M B c =6.46(15) GeV

Perturbative determination of mass-dependent renormalization and improvement coefficients for the heavy-light vector and axial-vector currents with relativistic heavy and domain-wall light quarks

International Nuclear Information System (INIS)

Yamada, Norikazu; Aoki, Sinya; Kuramashi, Yoshinobu

2005-01-01

We determine the mass-dependent renormalization as well as improvement coefficients for the heavy-light vector and axial-vector currents consisting of the relativistic heavy and the domain-wall light quarks through the standard matching procedure. The calculation is carried out perturbatively at the one-loop level to remove the systematic error of O(α s (am Q ) n ap) as well as O(α s (am Q ) n ) (n>=0), where p is a typical momentum scale in the heavy-light system. We point out that renormalization and improvement coefficients of the heavy-light vector current agree with those of the axial-vector current, thanks to the exact chiral symmetry for the light quark. The results obtained with three different gauge actions, plaquette, Iwasaki and DBW2, are presented as a function of heavy quark mass and domain-wall height

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

International Nuclear Information System (INIS)

Kniehl, B.A.; Kotikov, A.V.

2006-07-01

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.)

Searches for heavy resonances in all-jet final states with top quarks using jet substructure techniques with the CMS experiment

Energy Technology Data Exchange (ETDEWEB)

Usai, Emanuele

2017-12-15

While the Standard Model is very successful in describing subnuclear phenomena, it is not a complete theory of particle physics. Several new theories have been developed to address its issues. Many extensions of the Standard Model predict the existence of high-mass resonances. In some cases these resonances have an enhanced coupling to third generation quarks or to a hypothetical new generation of heavy non-chiral quarks. This thesis describes two searches for new phenomena compatible with these theories, in particular a search is presented for resonant top-antitop production, and the first search for heavy resonances decaying to a top quark and a heavy top quark partner T is shown. The searches target the all-jets decay channels and use data collected by the CMS Experiment at the CERN LHC between 2012 and 2015 at a center-of-mass energy of 8 TeV and 13 TeV. Due to the high mass of the resonances considered, the final state particles have a high Lorentz-boost. To reconstruct the hadronic decay of the top quarks and W bosons, jet substructure techniques such as top quark and W boson tagging algorithms, and boosted b jet identification are employed. These algorithms are studied with a particular focus on their validation and performance assessment. No signs of physics beyond the Standard Model are observed, but stringent limits are placed on the production of heavy resonances decaying to top-antitop quark pairs or a top quark and a heavy T quark.

Searches for heavy resonances in all-jet final states with top quarks using jet substructure techniques with the CMS experiment

International Nuclear Information System (INIS)

Usai, Emanuele

2017-12-01

While the Standard Model is very successful in describing subnuclear phenomena, it is not a complete theory of particle physics. Several new theories have been developed to address its issues. Many extensions of the Standard Model predict the existence of high-mass resonances. In some cases these resonances have an enhanced coupling to third generation quarks or to a hypothetical new generation of heavy non-chiral quarks. This thesis describes two searches for new phenomena compatible with these theories, in particular a search is presented for resonant top-antitop production, and the first search for heavy resonances decaying to a top quark and a heavy top quark partner T is shown. The searches target the all-jets decay channels and use data collected by the CMS Experiment at the CERN LHC between 2012 and 2015 at a center-of-mass energy of 8 TeV and 13 TeV. Due to the high mass of the resonances considered, the final state particles have a high Lorentz-boost. To reconstruct the hadronic decay of the top quarks and W bosons, jet substructure techniques such as top quark and W boson tagging algorithms, and boosted b jet identification are employed. These algorithms are studied with a particular focus on their validation and performance assessment. No signs of physics beyond the Standard Model are observed, but stringent limits are placed on the production of heavy resonances decaying to top-antitop quark pairs or a top quark and a heavy T quark.

On extracting heavy quark parameters from moments with cuts

International Nuclear Information System (INIS)

Bigi, I.I.; Uraltsev, N.

2004-01-01

We point out that the moments of the photon energy spectrum in B→X s +γ decays have a significant bias compared to the OPE expressions used to evaluate them, when a lower cut on the photon energy is imposed. This typically increases the value extracted for the apparent b quark mass by 70 MeV or more together with an even more dramatic reduction in the apparent value of the kinetic energy expectation value. These nonperturbative effects are exponential in the effective hardness of the transition, which is strongly lowered by high cuts, and do not reflect a breakdown of the 1/m b expansion itself. Similar effects in semileptonic b→c decays are briefly addressed. Accounting for the cut-related shifts brings different measurements into good agreement, when the OPE-based theory employs the 'robust' approach. We stress the utility of the second moment of E γ , once the aforementioned effects have been included

Nonperturbative determination of the QCD potential at O(1/m)

International Nuclear Information System (INIS)

Koma, Y.; Koma, M.; Wittig, H.

2006-07-01

The relativistic correction to the QCD static inter-quark potential at O(1/m) is investigated nonperturbatively for the first time by using lattice Monte Carlo QCD simulations. The correction is found to be comparable with the Coulombic term of the static potential when applied to charmonium, and amounts to 26% of the Coulombic term for bottomonium. (Orig.)

Nonperturbative QCD and quark-gluon plasma

Energy Technology Data Exchange (ETDEWEB)

Shuryak, E V [Department of Physics and Astronomy, State University of New York, Stony Brook (United States)

2002-09-15

This is a brief written version of 5 lectures made at 2001 ICTP Summer School on High Energy Physics in Trieste. The lectures provide an overview of what we have learned about QCD vacuum, hadrons and hot / dense hadronic matter during the last 2 decades. Last two lectures contain discussion of heavy ion physics. We focus on the first surprising results from new heavy ion collider, RHIC, as well as recent development toward understanding of the old problem of 'soft pomeron' in high energy hadronic collisions and its connection to new heavy ion data. (author)

Properties of the quark gluon plasma from lattice QCD

International Nuclear Information System (INIS)

Mages, Simon Wolfgang

2015-01-01

Quantum Chromodynamics (QCD) is the theory of the strong interaction, the theory of the interaction between the constituents of composite elementary particles (hadrons). In the low energy regime of the theory, standard methods of theoretical physics like perturbative approaches break down due to a large value of the coupling constant. However, this is the region of most interest, where the degrees of freedom of QCD, the color charges, form color-neutral composite elementary particles, like protons and neutrons. Also the transition to more energetic states of matter like the quark gluon plasma (QGP), is difficult to investigate with perturbative approaches. A QGP is a state of strongly interacting matter, which existed shortly after the Big Bang and can be created with heavy ion collisions for example at the LHC at CERN. In a QGP the color charges of QCD are deconfined. This thesis explores ways how to use the non-perturbative approach of lattice QCD to determine properties of the QGP. It focuses mostly on observables which are derived from the energy momentum tensor, like two point correlation functions. In principle these contain information on low energy properties of the QGP like the shear and bulk viscosity and other transport coefficients. The thesis describes the lattice QCD simulations which are necessary to measure the correlation functions and proposes new methods to extract these low energy properties. The thesis also tries to make contact to another non-perturbative approach which is Improved Holographic QCD. The aim of this approach is to use the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence to make statements about QCD with calculations of a five dimensional theory of gravity. This thesis contributes to that work by constraining the parameters of the model action by comparing the predictions with those of measurements with lattice QCD.

The Theory of Quark and Gluon Interactions

CERN Document Server

Ynduráin, Francisco J

2006-01-01

F. J. Ynduráin's book on Quantum Chromodynamics has become a classic among advanced textbooks. First published in 1983, and translated into Russian in 1986, it now sees its fourth edition. It addresses readers with basic knowledge of field theory and particle phenomenology. The author presents the basic facts of quark and gluon physics in pedagogical form. Theory is always confronted with experimental findings. The reader will learn enough to be able to follow modern research articles. This fourth edition presents a new section on heavy quark effective theories, more material on lattice QCD and on chiral perturbation theory.

Heavy quarks and strong binding: A field theory of hadron structure

International Nuclear Information System (INIS)

Bardeen, W.A.; Chanowitz, M.S.; Drell, S.D.; Weinstein, M.; Yan, T.

1975-01-01

We investigate in canonical field theory the possibility that quarks may exist in isolation as very heavy particles, M/sub quark/) very-much-greater-than 1 GeV, yet form strongly bound hadronic states, M/sub hadron/) approx. 1 GeV. In a model with spin-1/2 quarks coupled to scalar gluons we find that a mechanism exists for the formation of bound states which are much lighter than the free constituents. Following Nambu, we introduce a color interaction mediated by gauge vector mesons to guarantee that all states with nonvanishing triality have masses much larger than 1 GeV. The possibility of such a solution to a stronly coupled field theory is exhibited by a calculation employing the variational principle in tree approximation. This procedure reduces the field-theoretical problem to a set of coupled differential equations for classical fields which are just the free parameters of the variational state. A striking property of the solution is that the quark wave function is confined to a thin shell at the surface of the hadronic bound state. Though the quantum corrections to this procedure remain to be investigated systematically, we explore some of the phenomenological implications of the trial wave functions so obtained. In particular, we exhibit the low-lying meson and baryon multiplets of SU(6); their magnetic moments, charge radii, and radiative decays, and the axial charge of the baryons. States of nonvanishing momenta are constructed and the softness of the hadron shell to deformations in scattering processes is discussed qualitatively along with the implications for deep-inelastic electron scattering and dual resonance models

Quantum chromodynamics

CERN Document Server

Martinelli, Guido

1994-01-01

1, Hadrons as bound states of quarks and gluons. 2, Quark models, confinement and asymptotic freedom. 3, The parton model; Deep Inelastic Scattering (DIS) process. 4, The parton model and QCD. 5) Phenomenology of the parton model; muon and neutrino DIS, structure functions and parton distributions. 6) W and Z production at Colliders. 7) Weak decays and strong interactions. 8) Heavy flavours effective theories and QCD. 9) Non-perturbative QCD.

Quark imprisonment as the origin of strong interactions

CERN Document Server

Amati, Daniele

1974-01-01

A formal scheme is suggested in which the only dynamical ingredients are weak and electro-magnetic interactions with quarks and leptons treated on the same footing. Strong interactions are generated by the requirement that quarks do not appear physically. (7 refs).

Nonperturbative quark-gluon thermodynamics at finite density

Science.gov (United States)

Andreichikov, M. A.; Lukashov, M. S.; Simonov, Yu. A.

2018-03-01

Thermodynamics of the quark-gluon plasma at finite density is studied in the framework of the Field Correlator Method, where thermodynamical effects of Polyakov loops and color magnetic confinement are taken into account. Having found good agreement with numerical lattice data for zero density, we calculate pressure P(T,μ), for 0 confinement.

NNLO O(α4s) results for heavy quark pair production in quark-antiquark collisions. The one-loop squared contributions

International Nuclear Information System (INIS)

Koerner, J.G.

2008-02-01

We calculate the NNLO O(α 4 s ) one-loop squared corrections to the production of heavy quark pairs in quark-antiquark annihilations. These are part of the NNLO O(α 4 s ) radiative QCD corrections to this process. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in the dimensional regularization scheme. We find very intriguing factorization properties for the finite part of the amplitudes. (orig.)

Model for dynamical chiral symmetry breaking and quark condensate

International Nuclear Information System (INIS)

Nekrasov, M.L.; Rochev, V.E.

1986-01-01

In the framework of the model, proposed earlier to describe nonperturbative QCD, the singularity of the type 1/k 4 in the gluon propagator is shown to result in dynamical chiral symmetry breaking and appearance of quark condensate. The value, obtained for quark condensate, is close to the phenomenological one

Quark model calculations of current correlators in the nonperturbative domain

International Nuclear Information System (INIS)

Celenza, L.S.; Shakin, C.M.; Sun, W.D.

1995-01-01

The authors study the vector-isovector current correlator in this work, making use of a generalized Nambu-Jona-Lasinio (NJL) model. In their work, the original NJL model is extended to describe the coupling of the quark-antiquark states to the two-pion continuum. Further, a model for confinement is introduced that is seen to remove the nonphysical cuts that appear in various amplitudes when the quark and antiquark go on mass shell. Quite satisfactory results are obtained for the correlator. The authors also use the correlator to define a T-matrix for confined quarks and discuss a rho-dominance model for that T-matrix. It is also seen that the Bethe-Salpeter equation that determines the rho mass (in the absence of the coupling to the two-pion continuum) has more satisfactory behavior in the generalized model than in the model without confinement. That improved behavior is here related to the absence of the q bar q cut in the basic quark-loop integral of the generalized model. In this model, it is seen how one may work with both quark and hadron degrees of freedom, with only the hadrons appearing as physical particles. 12 refs., 16 figs., 1 tab

Non-perturbative versus perturbative renormalization of lattice operators

International Nuclear Information System (INIS)

Goeckeler, M.; Technische Hochschule Aachen; Horsley, R.; Ilgenfritz, E.M.; Oelrich, H.; Forschungszentrum Juelich GmbH; Schierholz, G.; Forschungszentrum Juelich GmbH; Perlt, H.; Schiller, A.; Rakow, P.

1995-09-01

Our objective is to compute the moments of the deep-inelastic structure functions of the nucleon on the lattice. A major source of uncertainty is the renormalization of the lattice operators that enter the calculation. In this talk we compare the renormalization constants of the most relevant twist-two bilinear quark operators which we have computed non-perturbatively and perturbatively to one loop order. Furthermore, we discuss the use of tadpole improved perturbation theory. (orig.)

Heavy quark form factors at two loops in perturbative QCD

International Nuclear Information System (INIS)

Ablinger, J.; Schneider, C.; Behring, A.; Falcioni, G.

2017-11-01

We present the results for heavy quark form factors at two-loop order in perturbative QCD for different currents, namely vector, axial-vector, scalar and pseudo-scalar currents, up to second order in the dimensional regularization parameter. We outline the necessary computational details, ultraviolet renormalization and corresponding universal infrared structure.

The heavy quark-antiquark potential from lattice and perturbative QCD

OpenAIRE

Laschka, Alexander; Kaiser, Norbert; Weise, Wolfram

2009-01-01

The heavy quark-antiquark potential in perturbative QCD is subject to ambiguities. We show how to derive a well-defined and stable short-distance potential that can be matched to results from lattice QCD simulations at intermediate distances. The static potential as well as the order 1/m potential are discussed.

Heavy quark form factors at two loops in perturbative QCD

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Behring, A. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Teilchenphysik und Kosmologie; Bluemlein, J.; Freitas, A. de; Marquard, P.; Rana, N. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Falcioni, G. [Nikhef, Amsterdam (Netherlands). Theory Group

2017-11-15

We present the results for heavy quark form factors at two-loop order in perturbative QCD for different currents, namely vector, axial-vector, scalar and pseudo-scalar currents, up to second order in the dimensional regularization parameter. We outline the necessary computational details, ultraviolet renormalization and corresponding universal infrared structure.

Heavy-flavour hadrons as probes of strongly-interacting matter: highlights from ALICE

CERN Multimedia

CERN. Geneva

2014-01-01

In Pb-Pb collisions the heavy-flavour nuclear modification factor together with the elliptic-flow measurements allow one to study the heavy-quark transport properties in the hot and dense medium. The production of heavy quarks in heavy-ion collisions is furthermore also affected by the presence of cold nuclear matter in the initial state. The study of p-Pb collisions is instrument...

Weak interactions, quark masses and spontaneous violation of parity

International Nuclear Information System (INIS)

Kingsley, R.L.

1976-09-01

A six quark model is discussed for the weak interactions of hadrons in which parity is violated spontaneously in an SU(2) x U(1) gauge theory. Quarks with very small masses are required and their weak interactions approximate those of the Weinberg-Salam model. Suppression of strangeness-changing neutral currents requires at least seven quarks. (author)

Prediction of beauty particle masses with the heavy quark effective theory

International Nuclear Information System (INIS)

Aglietti, U.

1992-01-01

Using symmetry properties of the static theory for heavy quarks, the spectrum of beauty particles is predicted in terms of the spectrum of charmed particles. A simple technique for cancelling spin dependent corrections to the static theory is explained and systematically applied. (orig.)

Nuclear matter descriptions including quark structure of the hadrons

International Nuclear Information System (INIS)

Huguet, R.

2008-07-01

It is nowadays well established that nucleons are composite objects made of quarks and gluons, whose interactions are described by Quantum chromodynamics (QCD). However, because of the non-perturbative character of QCD at the energies of nuclear physics, a description of atomic nuclei starting from quarks and gluons is still not available. A possible alternative is to construct effective field theories based on hadronic degrees of freedom, in which the interaction is constrained by QCD. In this framework, we have constructed descriptions of infinite nuclear matter in relativistic mean field theories taking into account the quark structure of hadrons. In a first approach, the in medium modifications of mesons properties is dynamically obtained in a Nambu-Jona-Lasinio (NJL) quark model. This modification is taken into account in a relativistic mean field theory based on a meson exchange interaction between nucleons. The in-medium modification of mesons masses and the properties of infinite nuclear matter have been studied. In a second approach, the long and short range contributions to the in-medium modification of the nucleon are determined. The short range part is obtained in a NJL quark model of the nucleon. The long range part, related to pions exchanges between nucleons, has been determined in the framework of Chiral Perturbation theory. These modifications have been used to constrain the couplings of a point coupling relativistic mean field model. A realistic description of the saturation properties of nuclear matter is obtained. (author)

On exact account of heavy quark thresholds in hard processes

International Nuclear Information System (INIS)

Dokshitzer, Yu. L.

1993-01-01

We study the problem to accurately account for the heavy quark threshold effects in hard processes. We employ the direction perturbative Feynman diagram analysis and the Stueckelberg-Bogoliubov massive renormalization group formalism to show that both methods results in the same prescription for the 'physical' mass-dependent QCD effective coupling as an argument of anomalous dimensions that determine the evolution of structure function (parton distributions). By considering the one-loop example, we demonstrate that an intrinsic ambiguity of the standard approach based on the notion of 'effective number of quark flavours' may affect the α s determination at the level of two-loop effects

Heavy quark physics from SLD

International Nuclear Information System (INIS)

Messner, R.

1997-01-01

This report covers preliminary measurements from SLD on heavy quark production at the Z 0 , using 150,000 hadronic Z 0 decays accumulated during the 1993-1995 runs. A measurement of R 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 b and A c by use of the left-right forward-backward asymmetry. The lifetimes of B + and B 0 mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p 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

Weak mixing and CP-violation involving heavy quarks and possible measurements in e+e- experiments

International Nuclear Information System (INIS)

Ali, A.; Aydin, Z.Z.

1978-09-01

We evaluate weak mass mixing among the neutral heavy mesons with a bottom (Q = -1/3) or top (Q = +2/3) quark and CP-violation in the frame work of six quark (V - A) models. It is argued that bottom and top mesons may distinguish the Higgs exchange mechanism of CP-violation from a complex phase in the quark mass matrix, if bottom and top quark masses are sufficiently different. Estimates of weak mixing-and CP-violating effects for e + e - experiments at PETRA, PEP and CESR energies are presented. (orig.) [de

The bound state problem and quark confinement

International Nuclear Information System (INIS)

Chaichian, M.; Demichev, A.P.; Nelipa, N.F.

1980-01-01

A quantum field-theoretic model in which quark is confined is considered. System of equations for the Green functions of colour singlet and octet bound states is obtained. The method is based on the nonperturbative Schwinger-Dyson equations with the use of Slavnov-Taylor identities. It is shown that in the framework of the model if there exist singlet, then also exist octet bound states of the quark-antiquark system. Thus in general, confinement of free quarks does not mean absence of their coloured bound states. (author)

Heavy Quark Impact Factor at Next-to-leading Level

OpenAIRE

Ciafaloni, Marcello; Rodrigo, German

2000-01-01

We further analyze the definition and the calculation of the heavy quark impact factor at next-to-leading (NL) log(s) level, and we provide its analytical expression in a previously proposed k-factorization scheme. Our results indicate that k-factorization holds at NL level with a properly chosen energy scale, and with the same gluonic Green's function previously found in the massless probe case.

Constituent quarks and charge particle production in heavy-ion collisions

International Nuclear Information System (INIS)

Mishra, Aditya Nath; Mazumder, Rakesh; Sahoo, Raghunath; Nandi, Basanta Kumar

2012-01-01

Relativistic heavy-ion collisions aims at producing a state of matter which is governed by partonic degree of freedom. The pseudorapidity density of particle multiplicity and transverse energy are the key observables which provide the properties of matter produced in heavy-ion collisions. Study of their dependence on centrality and collision energy is of paramount importance to understand the particle production mechanism. This may provide insight into the partonic phase that might be created in nuclear collisions. Here, in a constituent quarks framework, charged particle and transverse energy production in heavy-ion collisions are studied both as a function of centrality and collision energy, and hence the study gives a prediction for Pb + Pb collisions

Bright branes for strongly coupled plasmas

International Nuclear Information System (INIS)

Mateos, David; Patino, Leonardo

2007-01-01

We use holographic techniques to study photon production in a class of finite temperature, strongly coupled, large-N c SU(N c ) quark-gluon plasmas with N f c quark flavours. Our results are valid to leading order in the electromagnetic coupling constant but non-perturbatively in the SU(N c ) interactions. The spectral function of electromagnetic currents and other related observables exhibit an interesting structure as a function of the photon frequency and the quark mass. We discuss possible implications for heavy ion collision experiments

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.)

AAMQS: A non-linear QCD analysis of new HERA data at small-x including heavy quarks

International Nuclear Information System (INIS)

Albacete, Javier L.; Armesto, Nestor; Salgado, Carlos A.; Milhano, Jose Guilherme; Quiroga Arias, Paloma

2011-01-01

We present a global analysis of available data on inclusive structure functions and reduced cross sections measured in electron-proton scattering at small values of Bjorken-x, x<0.01, including the latest data from HERA on reduced cross sections. Our approach relies on the dipole formulation of DIS together with the use of the non-linear running coupling Balitsky-Kovchegov equation for the description of the small-x dynamics. We improve our previous studies by including the heavy quark (charm and beauty) contribution to the reduced cross sections, and also by considering a variable flavor scheme for the running of the coupling. We obtain a good description of the data, with the fit parameters remaining stable with respect to our previous analyses where only light quarks were considered. The inclusion of the heavy quark contributions resulted in a good description of available experimental data for the charm component of the structure function and reduced cross section provided the initial transverse distribution of heavy quarks was allowed to differ from (more specifically, to have a smaller radius than) that of the light flavors. (orig.)

AAMQS: A non-linear QCD analysis of new HERA data at small-x including heavy quarks

Energy Technology Data Exchange (ETDEWEB)

Albacete, Javier L. [CEA/Saclay, URA 2306, Unite de Recherche Associee au CNRS, Institut de Physique Theorique, Gif-sur-Yvette cedex (France); Armesto, Nestor; Salgado, Carlos A. [Universidade de Santiago de Compostela, Departamento de Fisica de Particulas and IGFAE, Santiago de Compostela (Spain); Milhano, Jose Guilherme [Instituto Superior Tecnico (IST), Universidade Tecnica de Lisboa, CENTRA, Lisboa (Portugal); Theory Unit, CERN, Physics Department, Geneve 23 (Switzerland); Quiroga Arias, Paloma [UPMC Univ. Paris 6 and CNRS UMR7589, LPTHE, Paris (France)

2011-07-15

We present a global analysis of available data on inclusive structure functions and reduced cross sections measured in electron-proton scattering at small values of Bjorken-x, x<0.01, including the latest data from HERA on reduced cross sections. Our approach relies on the dipole formulation of DIS together with the use of the non-linear running coupling Balitsky-Kovchegov equation for the description of the small-x dynamics. We improve our previous studies by including the heavy quark (charm and beauty) contribution to the reduced cross sections, and also by considering a variable flavor scheme for the running of the coupling. We obtain a good description of the data, with the fit parameters remaining stable with respect to our previous analyses where only light quarks were considered. The inclusion of the heavy quark contributions resulted in a good description of available experimental data for the charm component of the structure function and reduced cross section provided the initial transverse distribution of heavy quarks was allowed to differ from (more specifically, to have a smaller radius than) that of the light flavors. (orig.)

LEP1 measurement of heavy quark forward-backward asymmetries with Opal detector

International Nuclear Information System (INIS)

Lafoux, H.

1996-01-01

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 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□ and a Higgs boson mass between 60 and 1000 GeV/c□. (author). 159 refs., 88 figs., 37 tabs

Nonperturbative renormalization of nonlocal quark bilinears for quasi-PDFs on the lattice using an auxiliary field

Energy Technology Data Exchange (ETDEWEB)

Green, Jeremy; Jansen, Karl; Steffens, Fernanda [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

2017-07-15

Quasi-PDFs provide a path toward an ab initio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an auxiliary field, we can replace the nonlocal operator with a pair of local operators in an extended theory. On the lattice, this is closely related to the static quark theory. In this approach, we show how to understand the pattern of mixing that is allowed by chiral symmetry breaking, and obtain a master formula for renormalizing the nonlocal operator that depends on three parameters. We present an approach for nonperturbatively determining these parameters and use perturbation theory to convert to the MS scheme. Renormalization parameters are obtained for two lattice spacings using Wilson twisted mass fermions and for different discretizations of the Wilson line in the nonlocal operator. Using these parameters we show the effect of renormalization on nucleon matrix elements with pion mass approximately 370 MeV, and compare renormalized results for the two lattice spacings. The renormalized matrix elements are consistent among the different Wilson line discretizations and lattice spacings.

Nonperturbative renormalization of nonlocal quark bilinears for quasi-PDFs on the lattice using an auxiliary field

International Nuclear Information System (INIS)

Green, Jeremy; Jansen, Karl; Steffens, Fernanda

2017-07-01

Quasi-PDFs provide a path toward an ab initio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an auxiliary field, we can replace the nonlocal operator with a pair of local operators in an extended theory. On the lattice, this is closely related to the static quark theory. In this approach, we show how to understand the pattern of mixing that is allowed by chiral symmetry breaking, and obtain a master formula for renormalizing the nonlocal operator that depends on three parameters. We present an approach for nonperturbatively determining these parameters and use perturbation theory to convert to the MS scheme. Renormalization parameters are obtained for two lattice spacings using Wilson twisted mass fermions and for different discretizations of the Wilson line in the nonlocal operator. Using these parameters we show the effect of renormalization on nucleon matrix elements with pion mass approximately 370 MeV, and compare renormalized results for the two lattice spacings. The renormalized matrix elements are consistent among the different Wilson line discretizations and lattice spacings.

Non-leptonic weak decay rate of explicitly flavored heavy mesons

International Nuclear Information System (INIS)

Suzuki, M.; California Univ., Berkeley

1981-01-01

It is argued quantitatively that a large difference between the D 0 and D + lifetimes is mainly due to non-perturbative long-distance effects. The total non-leptonic weak decay rates are related to the soft limit of short-distance processes. Scaling laws for the decay rates of heavy mesons with respect to mass are inferred from the QCD analysis of the soft limit of fragmentation. It is found that the decay rates are not determined by the disconnected spectator diagrams alone even in the limit of the heavy quark mass M Going to infinity ( 5 exp √ c log M. Some numerical discussion is made for the decay of B mesons and T mesons. (orig.)

Nonperturbative Dynamics of Strong Interactions from Gauge/Gravity Duality

Energy Technology Data Exchange (ETDEWEB)

Grigoryan, Hovhannes [Louisiana State Univ., Baton Rouge, LA (United States)

2008-08-01

This thesis studies important dynamical observables of strong interactions such as form factors. It is known that Quantum Chromodynamics (QCD) is a theory which describes strong interactions. For large energies, one can apply perturbative techniques to solve some of the QCD problems. However, for low energies QCD enters into the nonperturbative regime, where di erent analytical or numerical tools have to be applied to solve problems of strong interactions. The holographic dual model of QCD is such an analytical tool that allows one to solve some nonperturbative QCD problems by translating them into a dual ve-dimensional theory de ned on some warped Anti de Sitter (AdS) background. Working within the framework of the holographic dual model of QCD, we develop a formalism to calculate form factors and wave functions of vector mesons and pions. As a result, we provide predictions of the electric radius, the magnetic and quadrupole moments which can be directly veri ed in lattice calculations or even experimentally. To nd the anomalous pion form factor, we propose an extension of the holographic model by including the Chern-Simons term required to reproduce the chiral anomaly of QCD. This allows us to nd the slope of the form factor with one real and one slightly o -shell photon which appeared to be close to the experimental ndings. We also analyze the limit of large virtualities (when the photon is far o -shell) and establish that predictions of the holographic model analytically coincide with those of perturbative QCD with asymptotic pion distribution amplitude. We also study the e ects of higher dimensional terms in the AdS/QCD model and show that these terms improve the holographic description towards a more realistic scenario. We show this by calculating corrections to the vector meson form factors and corrections to the observables such as electric radii, magnetic and quadrupole moments.

Asymmetries in heavy meson production from light quark fragmentation

International Nuclear Information System (INIS)

Dias de Deus, J.; Duraes, F.

2000-01-01

We discuss the possibility of the asymmetry in D - /D + production from π - beams, being a direct consequence of the properties of the light quark fragmentation function into heavy mesons. The main features of the asymmetry, as a function of x F , are easily described. An integrated sum rule for the D - , D + multiplicity difference is presented. Predictions for the asymmetry in B meson production are given. (orig.)

24th Annual Seminar on theoretical physics, Pretoria, 10-14 July 1989

International Nuclear Information System (INIS)

1989-01-01

This seminar contains 14 papers which are all indexed separately. Topics covered include: real-time green functions in perturbative thermal field theories; non-perturbative calculations in cavity-QCD; cavity-QCD in a background field and hadrons containing a heavy quark; the quark self-energy in a cavity; the hadron spectrum from lattice QCD; exotic hadrons and the isospin delection rule in K → π π decays; nucleon form factors in the relavistic harmonic oscillator potential for quarks; a dirac description of nuclear polarized beam scattering; coherent nuclear energy levels in a supermanifold; macroscopic description of low-lying isovector 1 + states in deformed nuclei; J/ψ suppression in ultra-relativistic heavy ion collisions; transport coefficients in ultra-relativistic heavy ion collisions; decay of interactions during dislocation unbinding in adlayers; and influence of electron-magnon interaction on electronic and magnetic properties of ferromagnetic 4f-systems

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.

A nonperturbative study of quarkonium systems

International Nuclear Information System (INIS)

Ma, J.P.; McKellar, H.J.

1995-01-01

Using nonrelativistic QCD on the lattice we studied the mass spectrum of quarkonium systems nonperturbatively for a range of the bar quark mass. We determined two products of the matrix elements involved in quarkonium decays and studied the mass dependence of the results. We predict from our calculations the leptonic decay width of Υ, and use the mass dependence to predict the leptonic decay width of J/ψ. These calculations agree with the experimental results. In lattice NRQCD an additional parameter n is introduced, and we study the sensitivity of our results to the choice of n. (authors). 10 refs., 2 figs

Identification of bottom-quarks in searches for new heavy resonances decaying into boosted top-quarks with the ATLAS detector and a development of an improved $b$-tagging algorithm

CERN Document Server

AUTHOR|(SzGeCERN)700216

From all the so far discovered elementary particles, the top-quark is the heaviest. Its large mass of $173.34\\GeV$ is unexplained and suggests that the top-quark may play a special role in nature, as it occurs in many beyond the Standard Model predictions. Several of these theories anticipate, the existence of heavy particles that decay predominantly into top-quark pairs. Searches for such new particles have been already performed by the experiments of the TEVATRON collider located at the Fermi National Accelerator Laboratory as well as by the two largest LHC experiments, ATLAS and CMS. Meanwhile, the exclusion limits on some of these models extend already up to $\\TeV$ mass scales. Thus the ongoing searches for new heavy particles decaying into top-quark pairs focus more strongly on events that contain high-$\\pt$ top-quarks. The decay products of a boosted top-quark (or any other highly boosted particle) can be strongly collimated and their signatures in the detector system might even have a significant overl...

Moving NRQCD for heavy-to-light form factors on the lattice

International Nuclear Information System (INIS)

Horgan, R.R.; Khomskii, L.; Meinel, S.

2009-06-01

We formulate Non-Relativistic Quantum Chromodynamics (NRQCD) on a lattice which is boosted relative to the usual discretization frame. Moving NRQCD (mNRQCD) allows us to treat the momentum for the heavy quark arising from the frame choice exactly. We derive mNRQCD through O(1/m 2 ,v 4 rel ), as accurate as the NRQCD action in present use, both in the continuum and on the lattice with O(a 4 ) improvements. We have carried out extensive tests of the formalism through calculations of two-point correlators for both heavy-heavy (bottomonium) and heavy-light (B s ) mesons in 2+1 flavor lattice QCD and obtained nonperturbative determinations of energy shift and external momentum renormalization. Comparison to perturbation theory at O(α s ) is also made. The results demonstrate the effectiveness of mNRQCD. In particular we show that the decay constants of heavy-light and heavy-heavy mesons can be calculated with small systematic errors up to much larger momenta than with standard NRQCD. (orig.)

Exploring heavy-quark energy loss via b-tagging in heavy-ion collisions at the LHC

International Nuclear Information System (INIS)

Klay, Jennifer L

2005-01-01

A strategy to study flavour-dependent parton energy loss by tagging heavy quark jets in p+p, p+Pb and Pb+Pb collisions at the LHC is discussed. Estimates for production cross-sections and experimental techniques employed at collider detectors to search QQ-bar jets are presented and a brief evaluation of the capabilities of CMS, ALICE and ATLAS detectors are given

Entanglement of heavy quark impurities and generalized gravitational entropy

Science.gov (United States)

Kumar, S. Prem; Silvani, Dorian

2018-01-01

We calculate the contribution from non-conformal heavy quark sources to the entanglement entropy (EE) of a spherical region in N=4 SUSY Yang-Mills theory. We apply the generalized gravitational entropy method to non-conformal probe D-brane embeddings in AdS5×S5, dual to pointlike impurities exhibiting flows between quarks in large-rank tensor representations and the fundamental representation. For the D5-brane embedding which describes the screening of fundamental quarks in the UV to the antisymmetric tensor representation in the IR, the EE excess decreases non-monotonically towards its IR asymptotic value, tracking the qualitative behaviour of the one-point function of static fields sourced by the impurity. We also examine two classes of D3-brane embeddings, one which connects a symmetric representation source in the UV to fundamental quarks in the IR, and a second category which yields the symmetric representation source on the Coulomb branch. The EE excess for the former increases from the UV to the IR, whilst decreasing and becoming negative for the latter. In all cases, the probe free energy on hyperbolic space with β = 2 π increases monotonically towards the IR, supporting its interpretation as a relative entropy. We identify universal corrections, depending logarithmically on the VEV, for the symmetric representation on the Coulomb branch.

ψ(3S) and Υ(5S) Originating in Heavy Meson Molecules: A Coupled Channel Analysis Based on an Effective Vector Quark–Quark Interaction

International Nuclear Information System (INIS)

Matsuda, Y.; Sakai, M.; Hirano, M.

2013-01-01

In our previous coupled channel analysis based on the Cornell effective quark–quark interaction, it was indicated that the ψ(3S) solution corresponding to ψ(4040) originates from a D ∗ D¯ ∗ channel state. In this article, we report on a simultaneous analysis of the ψ - and Υ-family states. The most conspicuous outcome is a finding that the Υ(5S) solution corresponding to Υ(10860) originates from a B ∗ B¯ ∗ channel state, very much like ψ(3S). Some other characteristics of the result, including the induced very large S–D mixing and relation of some of the solutions with newly observed heavy quarkonia-like states are discussed. (author)

Searches for baryons with multiple heavy quarks at LHCb

CERN Multimedia

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...

Impact of LHCb heavy-quark production cross sections on parton distribution functions at very low x

Energy Technology Data Exchange (ETDEWEB)

Zenaiev, Oleksandr [DESY, Notkestrasse 85, Hamburg 22607 (Germany)

2015-07-01

The impact of recent measurements of heavy-flavour production in deep inelastic ep scattering and in pp collisions on parton distribution functions is studied in a QCD analysis in the fixed-flavour-number scheme at next-to-leading order. Differential cross sections of charm- and beauty-quark production measured by LHCb are used together with inclusive and heavy-flavour production cross sections in deep inelastic scattering at HERA. The heavy-flavour data of the LHCb experiment impose additional constraints on the gluon and the sea-quark distributions at very low partonic fractions of the proton momenta, x < 10{sup -4}. This kinematic range is currently not covered by other experimental data in perturbative QCD fits.

Experimental developments in relativistic heavy-ion collisions published between Quark Matter 2002 and the beginning of Quark Matter 2004

International Nuclear Information System (INIS)

Hemmick, Thomas K

2004-01-01

The Quark Matter conference is the 'meeting of record' for the field of relativistic heavy-ion physics. Each such conference is filled with exciting new data frequently presented to the world for the first time. However, the field also makes significant progress during the 18 months between Quark Matter conferences. Such progress is summarized in a single talk near the beginning of the conference and sets the stage for the newest data and discoveries. This paper is the experimental summary of selected results published in journals and presented at conferences between the end of QM2002 and the beginning of QM2004

Quark pair creation in color electric fields and effects of magnetic fields

International Nuclear Information System (INIS)

Tanji, Noato

2010-01-01

The time evolution of a system where a uniform and classical SU(3) color electric field and quantum fields of quarks interact with each other is studied focusing on non-perturbative pair creation and its back reaction. We characterize a color direction of an electric field in a gauge invariant way, and investigate its dependence. Momentum distributions of created quarks show plasma oscillation as well as quantum effects such as the Pauli blocking and interference. Pressure of the system is also calculated, and we show that pair creation moderates degree of anisotropy of pressure. Furthermore, enhancement of pair creation and induction of chiral charge under a color magnetic field which is parallel to an electric field are discussed.

Heavy quarks fragmentation in charmed mesons in DELPHI experiment at LEP; Etude de la fragmentation des quarks lourds en mesons charmes dans l`experience Delphi au LEP

Energy Technology Data Exchange (ETDEWEB)

Levy, J.M.

1994-04-01

With the big statistics expected at LEP, the electroweak sector of the Standard Model can be tested as well as the theory of strong interactions. Quantum Chromo-Dynamics is indeed predictive for quarks properties, but does not explain how quarks fragment into hadrons. So far the hadronization can only be described with phenomenological models. The work presented in this thesis was performed on the DELPHI experiment at LEP and concerns the production and the fragmentation of heavy quarks into charmed mesons D , D* and D**. With the whole statistics of 1991 and 1992 (1 013 300 hadronic decays of the Z), more than 4500 charmed mesons decays have been reconstructed in the channels D{sup 0}{yields} K{sup -} {pi}{sup +} , D{sup +}{yields} K{sup -} {pi}{sup +}{pi}+ and D{sup *}+{yields} D{sup 0}{pi}{sup +} followed by D{sup 0}{yields} K{sup -}{pi}{sup +} . Using also 1993 data and the channel D{sup 0}{yields} K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} , evidence for D** production is presented. For the first time, the production rate is measured for each D meson separately for cc and bb contributions. In fact, D mesons can be produced either directly from the fragmentation of c quark or un-directly from the fragmentation of b quark into B mesons which decay into D mesons. (authors). 120 refs.

Theory of heavy quark-antiquark states

International Nuclear Information System (INIS)

Shifman, M.A.

1981-01-01

A brief review of data on Q anti Q quark-antiquark states is presented. Masses and leptonic widths of Q anti Q levels on the basis of QCD sum rules are determined. Spin effects in Q anti Q interactions are discussed. Hadronic transitions between quarkonium levels and the processes of tau/psi→γ + light hadrons, Y→γ + light hadrons are considered [ru

ΔS=O weak interactions at the quark level

International Nuclear Information System (INIS)

McKellar, B.H.J.

1987-01-01

The calculation of short distance gluon exchange corrections to the ΔS=O weak interaction at the quark level is described. Results are given for the coefficients of the 36 independent 4 quark operators involving ud, d, and s quarks explicitly, and for the 16 independent operators which remain when s quarks are eliminated and only u and d quarks explicitly occur in the operators. There is considerable uncertainty in the interpretation of parity violating phenomena in nuclei at the moment, as will be clear from the proceedings of this workshop. There is of course a possibility that our nuclear structure calculations are incomplete, but what I want to emphasize here is the fact that the existing calculations of the weak coupling constants at the hadronic level have been based on an inadequate quark level description. Little of what I have to say is new. I refer you to various papers by Rober Miller and myself on ΔS=1 interactions and ΔS=O interactions at the quark level, and to our review. However the only attempt to calculate observable effects using a quark level Hamiltonian with all of the necessary structure is that of Goldman and Preston and their work was a high energy rather than a low energy application. This paper is a pedagogical discussion of the basic physics of this ΔS=O weak Hamiltonian at the quark level, and is designed to encourage its use in future calculations of the weak hadronic coupling constants. Some previously unpublished results on a simplified approximate form of the ΔS=O Hamiltonian are given here to facilitate use of this quark level Hamiltonian in future calculations. (author)

Experimental investigations of strong interaction in the non-perturbative QCD region

International Nuclear Information System (INIS)

Lindenbaum, S.J.; Samuel, S.

1993-09-01

A critical investigation of non-perturbative QCD require investigating glueballs, search for a Quark Gluon Plasma (OGP), and search for strangelets. In the glueball area the data obtained (E- 881) at 8 GeV/c were analyzed for π - + p → φφn (OZI forbidden), φK + K - n (OZI allowed), K - p → φφ(ΛΣ) (OZI allowed), and bar pp → φφ → φφπ 0 (OZI forbidden), φK + K - π 0 (OZI allowed). By comparing the OZI forbidden (glueball filter reactions) with the OZI allowed and previous 22 GeV/c π - p → φφn or φK + K - n data a further critical test of the so far unsuccessfully challenged hypothesis that our g T (2010), g T '(2300) and g T double-prime(2340) all with I G J PC = 0 + 2 ++ are produced by 1-3 2 ++ glueballs will be made. In the QGP search with a large-solid-angle TPC a good Ξ signal was observed. The ratio of Ξ to single strange quark particles such as λ is a better indication of strangeness enhancement in QGP formation. The data indicate enhancement by a factor ∼ 2 over cascade model (corrected to observed strangeness) predictions, but it is definitely far from conclusive at this stage since the result is model dependent. Double λ topologies of the type needed to discover light strangelets in the nanosecond lifetime region were found. In addition, research has been accomplished in three main areas: bosonic technicolor and strings, buckministerfullerene C 60 and neutrino oscillations in a dense neutrino gas

Gravity dual corrections to the heavy quark potential at finite-temperature

International Nuclear Information System (INIS)

Grigoryan, Hovhannes R.; Kovchegov, Yuri V.

2011-01-01

We apply gauge/gravity duality to compute 1/N c 2 corrections to the heavy quark potentials of a quark-anti-quark pair (QQ-bar) and of a quark-quark pair (QQ) immersed into the strongly coupled N=4 SYM plasma. On the gravity side these corrections come from the exchanges of supergravity modes between two string worldsheets stretching from the UV boundary of AdS space to the black hole horizon in the bulk and smeared over S 5 . We find that the contributions to the QQ-bar potential coming from the exchanges of all of the relevant modes (such as dilaton, massive scalar, 2-form field, and graviton) are all attractive, leading to an attractive net QQ-bar potential. We show that at large separations r and/or high-temperature T the potential is of Yukawa-type, dominated by the graviton exchange, in agreement with earlier findings. On the other hand, at small-rT the QQ-bar potential scales as ∼(1/r)ln(1/rT). In the case of QQ potential the 2-form contribution changes sign and becomes repulsive: however, the net QQ potential remains attractive. At large-rT it is dominated by the graviton exchange, while at small-rT the QQ potential becomes Coulomb-like.

The quark propagator in a covariant gauge

International Nuclear Information System (INIS)

Bonnet, F.D.R.; Leinweber, D.B.; Williams, A.G.; Zanotti, J.M.

2000-01-01

Full text: The quark propagator is one of the fundamental building blocks of QCD. Results strongly depend on the ansatz for the propagator. Direct simulations of QCD on a space time lattice can provide guidance and constraints on the analytic structure of the quark propagator. On the lattice the infrared and asymptotic behaviour of the quark propagator is of particular interest since it is a reflection of the accuracy of the discretised quark action. In the deep infrared region, artefacts associated with the finite size of the lattice spacing become small. This is the most interesting region as nonperturbative physics lies here. However, the ultraviolet behaviour at large momentum of the propagator will in general strongly deviate from the correct continuum behaviour. This behaviour will be action dependent. Some interesting progress has been made in improving the ultraviolet behaviour of the propagator. A method, recently developed and referred to as tree-level correction, consists of using the knowledge of the tree-level behaviour to eliminate the obvious lattice artefacts. Tree-level correction represents a crucial step in extracting meaningful results for the mass function and the renormalisation function outside of the deep infrared region. The mass function is particularly interesting as it provides insights into the constituent quark mass as a measure of the nonperturbative physics. In this poster I will present results from the analytic structure of the propagator in recent lattice studies for a variety of fermion actions in lattice QCD. I will also present the new ratio method used to tree-level correct these quark propagators

Multi-Quarks and Two-Baryon Interaction in Lattice QCD

International Nuclear Information System (INIS)

Okiharu, F.; Suganuma, H.; Takahashi, T. T.; Doi, T.

2006-01-01

We study multi-quark (3Q,4Q,5Q) systems in lattice QCD. We perform the detailed studies of multi-quark potentials in lattice QCD to clarify the inter-quark interaction in multi-quark systems. We find that all the multi-quark potentials are well described by the OGE Coulomb plus multi-Y-type linear potential, i.e., the multi-Y Ansatz. For multi-quark systems, we observe lattice QCD evidences of 'flip-flop', i.e., flux-tube recombination. These lattice QCD studies give an important bridge between elementary particle physics and nuclear physics

Net charge of quark jets in (anti)neutrino interactions

International Nuclear Information System (INIS)

Teper, M.

1981-01-01

We analyse recent measurements of the net charges of quark jets in neutrino and antineutrino interactions. The data indicates that (i) the two quarks in the nucleon fragmentation region prefer to behave as a diquark rather than as a pair of independent quarks, and (ii) the struck quark does not appear to suffer any soft charge exchange of the kind that occurs when a valence quark inside a nucleon is slowed to x approx. O. (orig.)

Quark interactions and colour chemistry

International Nuclear Information System (INIS)

Hong-Mo, C.

1982-01-01

The interaction between quarks, according to the current theory of quantum chromodynamics, is similar to the electromagnetic interaction between electrons and nucleons, both being governed by locally gauge-invariant field theories. It is tempting therefore to discuss the spectroscopy of hadrons, which are quark composites bound by colour forces, in the same language as the spectroscopy of atoms and molecules which are bound states of electrons and nucleons held together by e.m. forces. Because of the difference in gauge groups, however, the dynamics are very different. Nonetheless, it appears likely that metastable multiquark hadron states can exist which are analogous to atoms and molecules in QED. In these lectures, tentative steps are taken in developing the rudiments of a new colour chemistry' of these 'atoms' and 'molecules'. (author)

NNLO O({alpha}{sup 4}{sub s}) results for heavy quark pair production in quark-antiquark collisions. The one-loop squared contributions

Energy Technology Data Exchange (ETDEWEB)

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

2008-02-15

We calculate the NNLO O({alpha}{sup 4}{sub s}) one-loop squared corrections to the production of heavy quark pairs in quark-antiquark annihilations. These are part of the NNLO O({alpha}{sup 4}{sub s}) radiative QCD corrections to this process. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in the dimensional regularization scheme. We find very intriguing factorization properties for the finite part of the amplitudes. (orig.)

Nonperturbative Renormalization of Composite Operators with Overlap Fermions

Energy Technology Data Exchange (ETDEWEB)

J.B. Zhang; N. Mathur; S.J. Dong; T. Draper; I. Horvath; F. X. Lee; D.B. Leinweber; K.F. Liu; A.G. Williams

2005-12-01

We compute non-perturbatively the renormalization constants of composite operators on a quenched 16{sup 3} x 28 lattice with lattice spacing a = 0.20 fm for the overlap fermion by using the regularization independent (RI) scheme. The quenched gauge configurations were generated with the Iwasaki action. We test the relations Z{sub A} = Z{sub V} and Z{sub S} = Z{sub P} and find that they agree well (less than 1%) above {mu} = 1.6 GeV. We also perform a Renormalization Group (RG) analysis at the next-to-next-to-leading order and match the renormalization constants to the {ovr MS} scheme. The wave-function renormalization Z{sub {psi}} is determined from the vertex function of the axial current and Z{sub A} from the chiral Ward identity. Finally, we examine the finite quark mass behavior for the renormalization factors of the quark bilinear operators. We find that the (pa){sup 2} errors of the vertex functions are small and the quark mass dependence of the renormalization factors to be quite weak.

Experimental investigations of strong interactions in non-perturbative QCD region

International Nuclear Information System (INIS)

Lindenbaum, S.J.; Samuel, S.

1992-01-01

We have experimentally investigated the reactions π - p → φφn (OZI forbidden), φK + K - n (OZI allowed), K - p →φφ{ σ λ } (OZI allowed),φK + K - { σ λ }(OZI allowed),bar pp → φ φ π 0 (OZI forbidden), φK + K - π 0 (OZI allowed). By comparing the OZI forbidden (glueball filter) reactions with the OZI allowed and taking a global view we hope to critically test our hypothesis that the g T (2010), g T' (2300), and g T double-prime(2340) all with I G J PC = 0 + 2 ++ are produced by 1--3 2 ++ glueballs. We have searched for a Quark-Gluon Plasma by using 14.6 GeV/c x A Si ions incident on Au, Cu and Si. The novel detector used was a large solid angle TPC system. Although we found considerable strangeness enhancement this is explainable by conventional cascade physics including N* production. We have been engaged in phenomenological analyses in both glueball and heavy ion work. We have found that the θ(1720) is the same as the 0 ++ f 0 (1720) we discovered earlier. Furthermore that the G(1590) can be explained as a sum of the f 0 (1400) and f 0 (1720) and does not require a new resonant state. We have also found that the strangeness enhancement discovered in heavy ion collisions so far is explainable by conventional physics. We are in the STAR Collaboration at RHIC which uses a large TPC system to search for a Quark-Gluon Plasma

Decays of mesons with charm quarks on the lattice

International Nuclear Information System (INIS)

Ali Khan, A.; Braun, V.; Burch, T.; Goeckeler, M.; Schaefer, A.; Schierholz, G.

2007-10-01

We investigate mesons containing charm quarks on fine lattices with a -1 ∝ 5 GeV. The quenched approximation is employed using theWilson gauge action at β = 6.6 and nonperturbatively O(a) improvedWilson quarks. We present results for decay constants using various interpolating fields and give preliminary results for form factors of semileptonic decays of D s mesons to light pseudoscalar mesons. (orig.)

Some peculiarities of conjoined hadroproduction of standard Higgs boson and heavy quark pair

International Nuclear Information System (INIS)

Bagdasaryan, A.S.; Egoryan, R.Sh.; Grigoryan, S.G.; Matinyan, S.G.

1986-01-01

A contribution to total cross section of conjoined hadroproduction of the H 0 -boson and the heavy quark pair Q and Q-bar (Q=c, b, t,...) from the H 0 -boson ''gluonic'' production diagrams (the so-called GGH-diagrams) is being discussed. A comparison is carried out between contributions to total cross sections from the GGH-diagrams and the H 0 -boson ''direct'' quark production diagrams (QH-diagrams). It is shown that with increasing M H the enhancement effect of the GGH contribution ''enters the game''

The spin and flavor content of intrinsic sea quarks

International Nuclear Information System (INIS)

Bo-Qiang Ma; Brodsky, S.J.

1997-07-01

The intrinsic quark-antiquark pairs generated by the minimal energy nonperturbative meson-baryon fluctuations in the nucleon sea provide a consistent framework for understanding a number of empirical anomalies observed in the deep inelastic quark-parton structure of nucleons: the flavor asymmetry of the nucleon sea implied by the violation of Gottfried sum rule, the proton spin problem implied by the violation of the Ellis-Jaffe sum rule, and the outstanding conflict between two different determinations of the strange quark sea in the nucleon

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

International Nuclear Information System (INIS)

Ablinger, J.; Schneider, C.; Hasselhuhn, A.; Round, M.; Manteuffel, A. von

2014-07-01

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 >> m 2 1(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 (3) 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 (3) 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 2 1 /m 2 2 .

Study of Heavy Flavours from Muons Measured with the ALICE Detector in Proton-Proton and Heavy-Ion Collisions at the CERN-LHC

CERN Document Server

Zhang, X; Zhou, D; Crochet, P

Ultra-relativistic heavy-ion collisions aim at investigating the properties ofstrongly-interacting matter at extreme conditions of temperature and energy density. According to quantum chromodynamics (QCD) calculations, under such conditions, the formation of a deconfined medium, the Quark-Gluon Plasma (QGP), is expected. Amongst the most important probes of the properties of the QGP, heavy quarks are of particular interest since they are expected to be produced in hard scattering processes during the early stage of the collision and subsequently interact with the hot and dense medium. Therefore, the measurement of quarkonium states and open heavy flavours should provide essential information on the properties of the system formed at the early stage of heavy-ion collisions. Indeed, open heavy flavours are expected to be sensitive to the energy density through the mechanism of in-medium energy loss of heavy quarks, while quarkonium production should be sensitive to the initial temperature of the system through ...