Quark mass effects in quark number susceptibilities
International Nuclear Information System (INIS)
Graf, Thorben; Petreczky, Peter
2017-01-01
The quark degrees of freedom of the QGP with special focus on mass effects are investigated. A next-to-leading-order perturbation theory approach with quark mass dependence is applied and compared to lattice QCD results. (paper)
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.)
International Nuclear Information System (INIS)
Bhaduri, Partha Pratim; Chattopadhyay, Subhasis
2010-01-01
Differential elliptic flow v 2 (p T ) for identified hadrons is investigated in the FAIR energy regime, employing a hadronic-string transport model (UrQMD) as well as a partonic transport model (AMPT). It is observed that both models show a mass ordering of v 2 at low p T and a switch-over resulting in a baryon-meson crossing at intermediate p T . AMPT generates higher v 2 values compared to UrQMD. In addition, constituent quark number scaling behavior of elliptic flow is addressed. Scaling behavior in terms of the transverse momentum p T is found to be absent for both the partonic and the hadronic model. However, UrQMD and AMPT with a string melting scenario do exhibit an NCQ scaling of v 2 to varying degrees, with respect to the transverse kinetic energy KE T . But the default AMPT, where partonic scatterings are not included, does not show any considerable scaling behavior. A variable α is defined to quantify the degree of KE T scaling. We found that UrQMD gives better scaling than AMPT at FAIR.
International Nuclear Information System (INIS)
Xu Shu-Sheng; Shi Chao; Cui Zhu-Fang; Zong Hong-Shi; Jiang Yu
2015-01-01
Generally speaking, the quark propagator is dependent on the quark chemical potential in the dense quantum chromodynamics (QCD). By means of the generating functional method, we prove that the quark propagator actually depends on p_4 + iμ from the first principle of QCD. The relation between quark number density and quark condensate is discussed by analyzing their singularities. It is concluded that the quark number density has some singularities at certain μ when T = 0, and the variations of the quark number density as well as the quark condensate are located at the same point. In other words, at a certain μ the quark number density turns to nonzero, while the quark condensate begins to decrease from its vacuum value. (paper)
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.
The quark mass and baryon numbers of empty chiral bags
International Nuclear Information System (INIS)
Jezabek, M.; Zalewski, K.
1984-01-01
We show that for spherical chiral bags the baryon number of the Dirac vacuum inside the bag does not depend on quark masses. Thus, the sum of the baryon numbers of an empty chiral bag and the skyrmion surrounding the bag is an integer, which depends on the boundary condition on the surface of the bag. This extends the result obtained by Goldstone and Jaffe for massless quarks. (orig.)
Influence of light-quark masses in dynamical scale breaking
International Nuclear Information System (INIS)
Barcelos Neto, J.; Chanda, R.
1984-01-01
It is demonstrated that light quark masses may significantly contribute to the logarithmic scale breaking in deep inelastic electromagnetic lepton-nucleon scattering. This is mainly due to the combination of scale variables together with large 'current' masses for u and d quarks, recently reported in the literature. Upper limits for current masses of u and d quarks, using positivity properties of the forward electromagnetic structure function F 2 of the nucleon are also estimated. (Author) [pt
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
Quark flavour conserving violations of the lepton number
Binétruy, Pierre; Lavignac, Stephane; Savoy, C A
1998-01-01
We study supersymmetric models of lepton and baryon number violation based on an abelian family gauge group. Due to possible lepton-Higgs mixing, the lepton violating couplings are related to the Yukawa couplings and may be generated by them even if they were absent in the original theory. Such terms may be dominant and are not given by the naive family charge counting rules. This enhancement mechanism can provide an alignment between lepton-number violating terms and Yukawa couplings: as a result they conserve quark flavour. A natural way of suppressing baryon number violation in this class of models is also proposed.
Improving the quark number susceptibilities for staggered fermions
International Nuclear Information System (INIS)
Gavai, Rajiv V.
2003-01-01
Quark number susceptibilities approach their ideal gas limit at sufficiently high temperatures. As in the case of other thermodynamic quantities, this limit itself is altered substantially on lattices with small temporal extent, N t = 4-8, making it thus difficult to check the validity of perturbation theory. Unlike other observables, improving susceptibilities or number densities is subject to constraints of current conservation and absence of chemical potential (μ) dependent divergences. We construct such an improved number density and susceptibility for staggered fermions and show that they approximate the continuum ideal gas limit better on small temporal lattices
Y-Scaling in a simple quark model
International Nuclear Information System (INIS)
Kumano, S.; Moniz, E.J.
1988-01-01
A simple quark model is used to define a nuclear pair model, that is, two composite hadrons interacting only through quark interchange and bound in an overall potential. An ''equivalent'' hadron model is developed, displaying an effective hadron-hadron interaction which is strongly repulsive. We compare the effective hadron model results with the exact quark model observables in the kinematic region of large momentum transfer, small energy transfer. The nucleon reponse function in this y-scaling region is, within the traditional frame work sensitive to the nucleon momentum distribution at large momentum. We find a surprizingly small effect of hadron substructure. Furthermore, we find in our model that a simple parametrization of modified hadron size in the bound state, motivated by the bound quark momentum distribution, is not a useful way to correlate different observables
Energy Technology Data Exchange (ETDEWEB)
Shekhter, V [AN SSSR, Leningrad. Inst. Yadernoj Fiziki
1981-04-01
The history is described of the concept of quarks, ie., hypothetical particles of which,hadrons (strongly interacting particles) are believed to consist. The quark properties differ from those of known elementary particles. The electric charge of quarks is 1/3 and 2/3 of the electron charge and they obviously only exist inside hadrons. Quark existence is generally recognized because it has been confirmed by experimental verification of predictions made using a quark model.
Hard-Thermal-Loop QCD thermodynamics and quark number susceptibility
Directory of Open Access Journals (Sweden)
Mogliacci Sylvain
2014-04-01
Full Text Available The weak-coupling expansion of the QCD pressure is known up to the order g6 log g. However, at experimentally relevant temperatures, the corresponding series is poorly convergent. In this proceedings, we discuss at which extent the gauge-invariant resummation scheme, Hard-Thermal-Loop perturbation theory (HTLpt, improves the apparent convergence. We first present HTLpt results for QCD thermodynamic functions up to three-loop order at vanishing chemical potential. Then, we report a preliminary HTLpt result of one-loop quark number susceptibility, probing the finite density equation of state. Our results are consistent with lattice data down to 2 − 3Tc, reinforcing the weakly-coupled quasiparticle picture in the intermediate coupling regime.
Quark-number susceptibility, thermodynamic sum rule, and the hard thermal loop approximation
International Nuclear Information System (INIS)
Chakraborty, Purnendu; Mustafa, Munshi G.; Thoma, Markus H.
2003-01-01
The quark number susceptibility, associated with the conserved quark number density, is closely related to the baryon and charge fluctuations in the quark-gluon plasma, which might serve as signature for the quark-gluon plasma formation in ultrarelativistic heavy-ion collisions. In addition to QCD lattice simulations, the quark number susceptibility has been calculated recently using a resummed perturbation theory (hard thermal loop resummation). In the present work we show, based on general arguments, that the computation of this quantity neglecting hard thermal loop vertices contradicts the Ward identity and violates the thermodynamic sum rule following from quark number conservation. We further show that the hard thermal loop perturbation theory is consistent with the thermodynamic sum rule
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.)
Probing high scale physics with top quarks at the Large Hadron Collider
Dong, Zhe
With the Large Hadron Collider (LHC) running at TeV scale, we are expecting to find the deviations from the Standard Model in the experiments, and understanding what is the origin of these deviations. Being the heaviest elementary particle observed so far in the experiments with the mass at the electroweak scale, top quark is a powerful probe for new phenomena of high scale physics at the LHC. Therefore, we concentrate on studying the high scale physics phenomena with top quark pair production or decay at the LHC. In this thesis, we study the discovery potential of string resonances decaying to t/tbar final state, and examine the possibility of observing baryon-number-violating top-quark production or decay, at the LHC. We point out that string resonances for a string scale below 4 TeV can be detected via the t/tbar channel, by reconstructing center-of-mass frame kinematics of the resonances from either the t/tbar semi-leptonic decay or recent techniques of identifying highly boosted tops. For the study of baryon-number-violating processes, by a model independent effective approach and focusing on operators with minimal mass-dimension, we find that corresponding effective coefficients could be directly probed at the LHC already with an integrated luminosity of 1 inverse femtobarns at 7 TeV, and further constrained with 30 (100) inverse femtobarns at 7 (14) TeV.
Two-colour QCD at finite fundamental quark-number density and related theories
International Nuclear Information System (INIS)
Hands, S.J.; Kogut, J.B.; Morrison, S.E.; Sinclair, D.K.
2001-01-01
We are simulating SU(2) Yang-Mills theory with four flavours of dynamical quarks in the fundamental representation of SU(2) 'colour' at finite chemical potential, μ for quark number, as a model for QCD at finite baryon number density. In particular we observe that for μ large enough this theory undergoes a phase transition to a state with a diquark condensate which breaks quark-number symmetry. In this phase we examine the spectrum of light scalar and pseudoscalar bosons and see evidence for the Goldstone boson associated with this spontaneous symmetry breaking. This theory is closely related to QCD at finite chemical potential for isospin, a theory which we are now studying for SU(3) colour
Two-colour QCD at finite fundamental quark-number density and related theories
International Nuclear Information System (INIS)
Hands, S. J.; Kogut, J. B.; Morrison, S. E.; Sinclair, D. K.
2000-01-01
We are simulating SU(2) Yang-Mills theory with four flavours of dynamical quarks in the fundamental representation of SU(2) colour at finite chemical potential, p for quark number, as a model for QCD at finite baryon number density. In particular we observe that for p large enough this theory undergoes a phase transition to a state with a diquark condensate which breaks quark-number symmetry. In this phase we examine the spectrum of light scalar and pseudoscalar bosons and see evidence for the Goldstone boson associated with this spontaneous symmetry breaking. This theory is closely related to QCD at finite chemical potential for isospin, a theory which we are now studying for SU(3) colour
The quark-hadron transition in systems with net baryon number
International Nuclear Information System (INIS)
Olive, K.A.; Harvard Univ., Cambridge, MA
1982-01-01
The transition from quark matter to hadronic matter is examined in systems with arbitrary chemical potentials corresponding to net baryon number. In the hardron phase, both a Reid-type potential for nucleons and the ππ potential derived from Weinberg's effective lagrangian have been included. In the quark phase, a linear confining potential has been considered. Results are most sensitive to the slope of the confining potential, although qualitatively the behavior of the thermodynamic properties remain unchanged. The critical baryon density is found to remain roughly constant for all temperatures below the critical temperature, Tsub(c), then falls rapidly to zero as T → Tsub(c). Below Tsub(c) this density is about 30n 0 for K = 0.18 GeV 2 (the slope of the quark potential) and 23n 0 for K = 0.10 GeV 2 . (orig.)
International Nuclear Information System (INIS)
Tyapkin, A.A.
1976-01-01
The problem is raised on the interpretation of quarks having fractional quantum numbers as structural quasi-particles. A new composite model is proposed on the basis of the fundamental triplet representation of fermions having integral quantum numbers
Quark number density and susceptibility calculation with one correction in mean field potential
International Nuclear Information System (INIS)
Singh, S. Somorendro
2016-01-01
We calculate quark number density and susceptibility of a model which has one loop correction in mean field potential. The calculation shows continuous increasing in the number density and susceptibility up to the temperature T = 0.4 GeV. Then the value of number density and susceptibility approach to the lattice result for higher value of temperature. The result indicates that the calculated values of the model fit well and the result increase the temperature to reach the lattice data with the one loop correction in the mean field potential. (author)
Quark and lepton masses at the GUT scale including supersymmetric threshold corrections
International Nuclear Information System (INIS)
Antusch, S.; Spinrath, M.
2008-01-01
We investigate the effect of supersymmetric (SUSY) threshold corrections on the values of the running quark and charged lepton masses at the grand unified theory (GUT) scale within the large tanβ regime of the minimal supersymmetric standard model. In addition to the typically dominant SUSY QCD contributions for the quarks, we also include the electroweak contributions for quarks and leptons and show that they can have significant effects. We provide the GUT scale ranges of quark and charged lepton Yukawa couplings as well as of the ratios m μ /m s , m e /m d , y τ /y b and y t /y b for three example ranges of SUSY parameters. We discuss how the enlarged ranges due to threshold effects might open up new possibilities for constructing GUT models of fermion masses and mixings.
Scaling studies of QCD with the dynamical highly improved staggered quark action
International Nuclear Information System (INIS)
Bazavov, A.; Freeman, W.; Toussaint, D.; Bernard, C.; Laiho, J.; DeTar, C.; Levkova, L.; Oktay, M.; Gottlieb, Steven; Heller, U. M.; Hetrick, J. E.; Osborn, J.; Sugar, R. L.; Van de Water, R. S.
2010-01-01
We study the lattice spacing dependence, or scaling, of physical quantities using the highly improved staggered quark (HISQ) action introduced by the HPQCD/UKQCD Collaboration, comparing our results to similar simulations with the asqtad fermion action. Results are based on calculations with lattice spacings approximately 0.15, 0.12, and 0.09 fm, using four flavors of dynamical HISQ quarks. The strange and charm quark masses are near their physical values, and the light-quark mass is set to 0.2 times the strange-quark mass. We look at the lattice spacing dependence of hadron masses, pseudoscalar meson decay constants, and the topological susceptibility. In addition to the commonly used determination of the lattice spacing through the static quark potential, we examine a determination proposed by the HPQCD Collaboration that uses the decay constant of a fictitious ''unmixed ss'' pseudoscalar meson. We find that the lattice artifacts in the HISQ simulations are much smaller than those in the asqtad simulations at the same lattice spacings and quark masses.
Variable-flavor-number scheme in analysis of heavy-quark electro-production data
International Nuclear Information System (INIS)
Alekhin, S.; Bluemlein, J.; Klein, S.; Moch, S.
2009-08-01
We check the impact of the factorization scheme employed in the calculation of the heavy-quark deep-inelastic scattering (DIS) electro-production on the PDFs determined in the NNLO QCD analysis of the world inclusive neutral-current DIS data combined with the ones on the neutrino-nucleon DIS di-muon production and the fixed-target Drell-Yan process. The charm-quark DIS contribution is calculated in the general-mass variable-flavor-number (GMVFN) scheme: At asymptotically large values of the momentum transfer Q it is given by the zero-mass 4-flavor scheme and at the value of Q equal to the charm-quark mass it is smoothly matched with the 3-flavor scheme using the Buza-Matiounine-Smith-van Neerven prescription. The PDFs obtained in this variant of the fit are very similar to the ones obtained in the fit with a 3-flavor scheme employed. Our 5-flavor PDFs derived from the 3-flavor ones using the NNLO matching conditions are used to calculate the rates of W ± /Z and t anti t production at the Tevatron collider and the LHC at NNLO. (orig.)
Tidal Love numbers of neutron and self-bound quark stars
International Nuclear Information System (INIS)
Postnikov, Sergey; Prakash, Madappa; Lattimer, James M.
2010-01-01
Gravitational waves from the final stages of inspiraling binary neutron stars are expected to be one of the most important sources for ground-based gravitational wave detectors. The masses of the components are determinable from the orbital and chirp frequencies during the early part of the evolution, and large finite-size (tidal) effects are measurable toward the end of inspiral, but the gravitational wave signal is expected to be very complex at this time. Tidal effects during the early part of the evolution will form a very small correction, but during this phase the signal is relatively clean. The accumulated phase shift due to tidal corrections is characterized by a single quantity related to a star's tidal Love number. The Love number is sensitive, in particular, to the compactness parameter M/R and the star's internal structure, and its determination could provide an important constraint to the neutron star radius. We show that Love numbers of self-bound strange quark matter stars are qualitatively different from those of normal neutron stars. Observations of the tidal signature from coalescing compact binaries could therefore provide an important, and possibly unique, way to distinguish self-bound strange quark stars from normal neutron stars. Tidal signatures from self-bound strange quark stars with masses smaller than 1M · are substantially smaller than those of normal stars owing to their smaller radii. Thus tidal signatures of stars less massive than 1M · are probably not detectable with Advanced LIGO. For stars with masses in the range 1-2M · , the anticipated efficiency of the proposed Einstein telescope would be required for the detection of tidal signatures.
Strange star candidates revised within a quark model with chiral mass scaling
Institute of Scientific and Technical Information of China (English)
Ang Li; Guang-Xiong Peng; Ju-Fu Lu
2011-01-01
We calculate the properties of static strange stars using a quark model with chiral mass scaling. The results are characterized by a large maximum mass (～ 1.6 M⊙) and radius (～ 10 km). Together with a broad collection of modern neutron star models, we discuss some recent astrophysical observational data that could shed new light on the possible presence of strange quark matter in compact stars. We conclude that none of the present astrophysical observations can prove or confute the existence of strange stars.
Scaling behavior in first-order quark-hadron phase transition
International Nuclear Information System (INIS)
Hwa, R.C.
1994-01-01
It is shown that in the Ginzburg-Landau description of first-order quark-hadron phase transition the normalized factorial moments exhibit scaling behavior. The scaling exponent ν depends on only one effective parameter g, which characterizes the strength of the transition. For a strong first-order transition, we find ν=1.45. For weak transition it is 1.30 in agreement with the earlier result on second-order transition
Quantum numbers of anti-grand-unified-theory Higgs fields from the quark-lepton spectrum
International Nuclear Information System (INIS)
Froggatt, C.D.; Nielsen, H.B.; Smith, D.J.
2002-01-01
A series of Higgs field quantum numbers in the anti-grand-unification model, based on the gauge group SMG 3 xU(1) f , is tested against the spectrum of quark and lepton masses and mixing angles. A more precise formulation of the statement that the couplings are assumed of order unity is given. It is found that the corrections coming from this more precise assumption do not contain factors of the order of the number of colors, N c =3, as one could have feared. We also include a combinatorial correction factor, taking account of the distinct internal orderings within the chain Feynman diagrams in our statistical estimates. Strictly speaking our model predicts that the uncertainty in its predictions and thus the accuracy of our fits should be ±60%. Many of the best fitting quantum numbers give a higher accuracy fit to the masses and mixing angles, although within the expected fluctuations in a χ 2 . This means that our fit is as good as it can possibly be
International Nuclear Information System (INIS)
Matveev, V.A.; Tavkhelidze, A.N.
2006-01-01
A brief review is given of the priority works which were mainly carried out at the Laboratory of Theoretical Physics, JINR, and devoted to the introduction to hadron physics of the concept of color and colored quarks, and to the description of hadrons in the framework of the model of quasi-free quarks. These ideas play a key role in the modern theory of strong interactions - quantum chromodynamics
Continuum-limit scaling of overlap fermions as valence quarks
International Nuclear Information System (INIS)
Cichy, Krzysztof; Herdoiza, Gregorio; Jansen, Karl
2009-10-01
We present the results of a mixed action approach, employing dynamical twisted mass fermions in the sea sector and overlap valence fermions, with the aim of testing the continuum limit scaling behaviour of physical quantities, taking the pion decay constant as an example. To render the computations practical, we impose for this purpose a fixed finite volume with lattice size L∼1.3 fm. We also briefly review the techniques we have used to deal with overlap fermions. (orig.)
Perturbation theory of the quark-gluon plasma at finite temperature and baryon number density
International Nuclear Information System (INIS)
Anon.
1984-01-01
At very high energy densities, hadronic matter becomes an almost ideal gas of quarks and gluons. In these circumstances, the effects of particle interactions are small, and to some order in perturbation theory are computable by methods involving weak coupling expansions. To illustrate the perturbative methods which may be used to compute the thermodynamic potential, the results and methods which are employed to compute to first order in α/sub s/ are reviewed. The problem of the plasmon effect, and the necessity of using non-perturbative methods when going beyond first order in α/sub s/ in evaluating the thermodynamic potential are discussed. The results at zero temperature and finite baryon number density to second order in α/sub s/ are also reviewed. The method of renormalization group improving the weak coupling expansions by replacing the expansion by an expansion in a temperature and baryon number density dependent coupling which approaches zero at high energy densities is discussed. Non-perturbative effects such as instantons are briefly mentioned and the breakdown of perturbation theory for the thermodynamical at order α/sub s/ 3 for finite temperature is presented
Quark parton model with logarithmic scaling violation and high energy neutrino interactions
International Nuclear Information System (INIS)
Isaev, P.S.; Kovalenko, S.G.
1979-01-01
In the framework of the proposed earlier quark parton model with logarithmic scaling violation the cross sections of deep inelastic ν(anti ν)N interactions are calculated, the contribution of the charmed particle production are evaluated. The kinematical mass corrections to scaling violations and threshold effects are taken into account. Joint analysis of the experimental data on deep inelastic ep, ed scattering and charged current neutrino interaction are performed by using the unique set of free parameters of the model. Evaluations of the c-quark and W-boson masses are obtained. Neutral current data as well are analysed. The analysis is performed with taken into account scaling violation effects. The obtained estimations of the charmed quark mass Msub(c)=3.0+-1.2 GeV. W-boson mass Mw=50+-10 GeV, and the Weinberg angle SINsup(2)THETAsub(w)=0.26+-0.04 are within errors in agreement with the generally accepted ones
Scaling of the quark-antiquark potential and improved actions in SU(2) lattice gauge theory
International Nuclear Information System (INIS)
Montvay, I.; Gutbrod, F.
1983-11-01
The scaling behaviour of the quark-antiquark potential is investigated by a high statistics Monte Carlo calculation in SU(2) lattice gauge theory. Besides the standard one-plaquette action we also use Symanzik's tree-level improved action and Wilson's block-spin improved action. No significant differences between Symanzik's action and the standard action have been observed. For small β Wilson's action scales differently. The string tension value chi extracted from the data corresponds to Λsub(latt) = (0.018 +- 0.001) √chi for the one-plaquette action. (orig.)
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
Geometric Scaling Analysis of Deep Inelastic Scattering Data Including Heavy Quarks
International Nuclear Information System (INIS)
Wu Qing-Dong; Zeng Ji; Hu Yuan-Yuan; Li Quan-Bo; Xiang Wen-Chang; Zhou Dai-Cui
2016-01-01
An analytic massive total cross section of photon-proton scattering is derived, which has geometric scaling. A geometric scaling is used to perform a global analysis of the deep inelastic scattering data on inclusive structure function F_2 measured in lepton–hadron scattering experiments at small values of Bjorken x. It is shown that the descriptions of the inclusive structure function F_2 and longitudinal structure function F_L are improved with the massive analytic structure function, which may imply the gluon saturation effect dominating the parton evolution process at HERA. The inclusion of the heavy quarks prevent the divergence of the lepton–hadron cross section, which plays a significant role in the description of the photoproduction region. (paper)
Thermal recombination: Beyond the valence quark approximation
Energy Technology Data Exchange (ETDEWEB)
Mueller, B. [Department of Physics, Duke University, Durham, NC 27708 (United States); Fries, R.J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)]. E-mail: fries@physics.umn.edu; Bass, S.A. [Department of Physics, Duke University, Durham, NC 27708 (United States); RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)
2005-07-07
Quark counting rules derived from recombination models agree well with data on hadron production at intermediate transverse momenta in relativistic heavy-ion collisions. They convey a simple picture of hadrons consisting only of valence quarks. We discuss the inclusion of higher Fock states that add sea quarks and gluons to the hadron structure. We show that, when recombination occurs from a thermal medium, hadron spectra remain unaffected by the inclusion of higher Fock states. However, the quark number scaling for elliptic flow is somewhat affected. We discuss the implications for our understanding of data from the Relativistic Heavy Ion Collider.
An advanced course in computational nuclear physics bridging the scales from quarks to neutron stars
Lombardo, Maria; Kolck, Ubirajara
2017-01-01
This graduate-level text collects and synthesizes a series of ten lectures on the nuclear quantum many-body problem. Starting from our current understanding of the underlying forces, it presents recent advances within the field of lattice quantum chromodynamics before going on to discuss effective field theories, central many-body methods like Monte Carlo methods, coupled cluster theories, the similarity renormalization group approach, Green’s function methods and large-scale diagonalization approaches. Algorithmic and computational advances show particular promise for breakthroughs in predictive power, including proper error estimates, a better understanding of the underlying effective degrees of freedom and of the respective forces at play. Enabled by recent improvements in theoretical, experimental and numerical techniques, the state-of-the art applications considered in this volume span the entire range, from our smallest components – quarks and gluons as the mediators of the strong force – to the c...
International Nuclear Information System (INIS)
Degtyarenko, P.V.; Efremenko, Yu.V.; Fedorov, V.B.
1991-01-01
Energy and A-dependencies of cumulative Λ 0 particle spectra for the particles emitted at angle 90 deg have been studied by means of electronic method; its polarization has been determined. Obtained data are analyzed both in terms of nuclear scaling phenomena and of possible existence of baryonrich quark-gluon plasma and are compared with other known data on cumulative particle formation. 31 refs.; 8 figs
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
Energy Technology Data Exchange (ETDEWEB)
Wicke, Daniel; /Wuppertal U., Dept. Math.
2009-08-01
Tevatron experiments CDF and D0 and was the last of the quarks to be discovered. As the partner of the bottom quark the top quark is expected to have quantum numbers identical to that of the other known up-type quarks. Only the mass is a free parameter. We now know that it is more than 30 times heavier than the next heaviest quark, the bottom quark. Thus, within the Standard Model all production and decay properties are fully defined. Having the complete set of quarks further allows to verify constraints that the Standard Model puts on the sum of all quarks or particles. This alone is reason enough to experimentally study the top quark properties. The high value of the top quark mass and its closeness to the electroweak scale has inspired people to speculate that the top quark could have a special role in the electroweak symmetry breaking. Confirming the expected properties of the top quark experimentally establishes the top quark as we expect it to be. Any deviation from the expectations gives hints to new physics that may help to solve the outstanding questions. In this review the recent results on top quark properties obtained by the Tevatron experiments CDF and D0 are summarized. At the advent of the LHC special emphasis is given to the basic measurement methods and the dominating systematic uncertainties. After a short introduction to the Standard Model and the experimental environment in the remainder of this chapter, Chapter 2 describes the current status of top quark mass measurements. Then measurments of interaction properties are described in Chapter 3. Finally, Chapter 4 deals with analyses that consider hypothetical particles beyond the Standard Model in the observed events.
International Nuclear Information System (INIS)
Wicke, Daniel
2009-01-01
Tevatron experiments CDF and D0 and was the last of the quarks to be discovered. As the partner of the bottom quark the top quark is expected to have quantum numbers identical to that of the other known up-type quarks. Only the mass is a free parameter. We now know that it is more than 30 times heavier than the next heaviest quark, the bottom quark. Thus, within the Standard Model all production and decay properties are fully defined. Having the complete set of quarks further allows to verify constraints that the Standard Model puts on the sum of all quarks or particles. This alone is reason enough to experimentally study the top quark properties. The high value of the top quark mass and its closeness to the electroweak scale has inspired people to speculate that the top quark could have a special role in the electroweak symmetry breaking. Confirming the expected properties of the top quark experimentally establishes the top quark as we expect it to be. Any deviation from the expectations gives hints to new physics that may help to solve the outstanding questions. In this review the recent results on top quark properties obtained by the Tevatron experiments CDF and D0 are summarized. At the advent of the LHC special emphasis is given to the basic measurement methods and the dominating systematic uncertainties. After a short introduction to the Standard Model and the experimental environment in the remainder of this chapter, Chapter 2 describes the current status of top quark mass measurements. Then measurments of interaction properties are described in Chapter 3. Finally, Chapter 4 deals with analyses that consider hypothetical particles beyond the Standard Model in the observed events.
International Nuclear Information System (INIS)
Kramer, G.; Spiesberger, H.; Cape Town Univ., Rondebosch
2015-09-01
We present predictions for b-quark production in photoproduction and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e + e - data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.
International Nuclear Information System (INIS)
Grinstein, S.; Mostafa, M.; Piegaia, R.; Alves, G.A.; Carvalho, W.; Maciel, A.K.; Motta, H. da; Oliveira, E.; Santoro, A.; Lima, J.G.; Oguri, V.; Gomez, B.; Hoeneisen, B.; Mooney, P.; Negret, J.P.; Ducros, Y.; Beri, S.B.; Bhatnagar, V.; Kohli, J.M.; Singh, J.B.; Shivpuri, R.K.; Acharya, B.S.; Banerjee, S.; Dugad, S.R.; Gupta, A.; Krishnaswamy, M.R.; Mondal, N.K.; Narasimham, V.S.; Parua, N.; Shankar, H.C.; Park, Y.M.; Choi, S.; Kim, S.K.; Castilla-Valdez, H.; Gonzalez Solis, J.L.; Hernandez-Montoya, R.; Magana-Mendoza, L.; Sanchez-Hernandez, A.; Pawlik, B.; Gavrilov, V.; Gershtein, Y.; Kuleshov, S.; Belyaev, A.; Dudko, L.V.; Ermolov, P.; Karmanov, D.; Leflat, A.; Manankov, V.; Merkin, M.; Shabalina, E.; Abramov, V.; Babintsev, V.V.; Bezzubov, V.A.; Bojko, N.I.; Burtovoi, V.S.; Chekulaev, S.V.; Denisov, S.P.; Dyshkant, A.; Eroshin, O.V.; Evdokimov, V.N.; Galyaev, A.N.; Goncharov, P.I.; Gurzhiev, S.N.; Kostritskiy, A.V.; Kozelov, A.V.; Kozlovsky, E.A.; Mayorov, A.A.; Babukhadia, L.; Davis, K.; Fein, D.; Forden, G.E.; Guida, J.A.; Johns, K.; Nang, F.; Narayanan, A.; Rutherfoord, J.; Shupe, M.; Aihara, H.; Barberis, E.; Clark, A.R.
1999-01-01
We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120 pb -1 of data collected in p bar p collisions at √ (s) =1.8 TeV by the D0 Collaboration during 1992 - 1996. No deviation from standard model expectations is observed. We use the data to set limits on the quark-electron compositeness scale. The 95% confidence level lower limits on the compositeness scale vary between 3.3 and 6.1thinspthinspTeV depending on the assumed form of the effective contact interaction. copyright 1999 The American Physical Society
International Nuclear Information System (INIS)
Gasiorowicz, S.; Rosner, J.L.
1982-01-01
The quark model began as little more than a quantum-number counting device. After a brief period during which quarks only played a symmetry role, serious interest in quark dynamics developed. The marriage of the principle of local gauge invariance and quarks has been astonishingly productive. Although many questions still need to be be answered, there is little doubt that the strong, weak and electroweak interactions of matter are described by gauge theories of interactions of the quarks. This review is focussed on the successes
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
Energy Technology Data Exchange (ETDEWEB)
Naumann-Emme, Sebastian
2011-07-15
In this thesis, pairs of top quarks produced in proton-proton collisions at a center-of-mass energy of 7 TeV and decaying in the muon+jets channel t anti t {yields} (b{mu}{nu})(bqq{sup '}) are analyzed using data that were recorded by the CMS detector in the year 2010 and correspond to an integrated luminosity of 35.9 pb{sup -1}. A sample of 78 events is selected by requiring exactly one isolated muon and at least four jets, two of them being identified as jets from the decay of b quarks. Given these selection criteria, the expected fraction of t anti t events is 94%. The trijet mass, M3, and the dijet mass, M2, are reconstructed, taking into account the b-tagging information. M3 and M2 are estimators of the masses of hadronically decaying top quarks and the corresponding W bosons, respectively. Templates for M2 and for the event-wise mass difference {delta}M{sub 32}=M3-M2 are parametrized as linear functions of the top quark mass, m{sub t}, and the jet energy scale (JES). Based on the precise knowledge of the W boson mass, M2 provides a strong handle on the energy scale of jets from light quarks. The reconstructed M2 and {delta}M{sub 32} in data are compared to the template functions from simulation in a combined likelihood fit. The overall JES in the selected sample is found to be 1.048{+-}0.040(stat){+-}0.015(syst) relative to the simulated JES and the measured m{sub t} is 167.8{+-}7.1(stat+JES){+-}3.1(syst) GeV. This is one of the first measurements of m{sub t} at the Large Hadron Collider. Furthermore, the JES measurement is an important input for the commissioning of the CMS experiment for the upcoming measurements with more data in the near future. (orig.)
International Nuclear Information System (INIS)
Naumann-Emme, Sebastian
2011-07-01
In this thesis, pairs of top quarks produced in proton-proton collisions at a center-of-mass energy of 7 TeV and decaying in the muon+jets channel t anti t → (bμν)(bqq ' ) are analyzed using data that were recorded by the CMS detector in the year 2010 and correspond to an integrated luminosity of 35.9 pb -1 . A sample of 78 events is selected by requiring exactly one isolated muon and at least four jets, two of them being identified as jets from the decay of b quarks. Given these selection criteria, the expected fraction of t anti t events is 94%. The trijet mass, M3, and the dijet mass, M2, are reconstructed, taking into account the b-tagging information. M3 and M2 are estimators of the masses of hadronically decaying top quarks and the corresponding W bosons, respectively. Templates for M2 and for the event-wise mass difference ΔM 32 =M3-M2 are parametrized as linear functions of the top quark mass, m t , and the jet energy scale (JES). Based on the precise knowledge of the W boson mass, M2 provides a strong handle on the energy scale of jets from light quarks. The reconstructed M2 and ΔM 32 in data are compared to the template functions from simulation in a combined likelihood fit. The overall JES in the selected sample is found to be 1.048±0.040(stat)±0.015(syst) relative to the simulated JES and the measured m t is 167.8±7.1(stat+JES)±3.1(syst) GeV. This is one of the first measurements of m t at the Large Hadron Collider. Furthermore, the JES measurement is an important input for the commissioning of the CMS experiment for the upcoming measurements with more data in the near future. (orig.)
Abbaspour, S.; Mohammad Moosavi Nejad, S.
2018-05-01
Charged Higgs bosons are predicted by some non-minimal Higgs scenarios, such as models containing Higgs triplets and two-Higgs-doublet models, so that the experimental observation of these bosons would indicate physics beyond the Standard Model. In the present work, we introduce a channel to indirect search for the charged Higgses through the hadronic decay of polarized top quarks where a top quark decays into a charged Higgs H+ and a bottom-flavored meson B via the hadronization process of the produced bottom quark, t (↑) →H+ + b (→ B + jet). To obtain the energy spectrum of produced B-mesons we present, for the first time, an analytical expression for the O (αs) corrections to the differential decay width of the process t →H+ b in presence of a massive b-quark in the General-Mass Variable-Flavor-Number (GM-VFN) scheme. We find that the most reliable predictions for the B-hadron energy spectrum are made in the GM-VFN scheme, specifically, when the Type-II 2HDM scenario is concerned.
Measurements and searches with top quarks
International Nuclear Information System (INIS)
Peters, Reinhild Yvonne
2008-01-01
In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t(bar t)H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more channels
Predicting {theta}{sub 13} and the neutrino mass scale from quark lepton mass hierarchies
Energy Technology Data Exchange (ETDEWEB)
Buchmueller, W.; Domcke, V.; Schmitz, K.
2011-11-15
Flavour symmetries of Froggatt-Nielsen type can naturally reconcile the large quark and charged lepton mass hierarchies and the small quark mixing angles with the observed small neutrino mass hierarchies and their large mixing angles. We point out that such a flavour structure, together with the measured neutrino mass squared differences and mixing angles, strongly constrains yet undetermined parameters of the neutrino sector. Treating unknown O(1) parameters as random variables, we obtain surprisingly accurate predictions for the smallest mixing angle, sin{sup 2}2{theta}{sub 13}=0.07{sup +0.11}{sub -0.05}, the smallest neutrino mass, m{sub 1}=2.5{sup +1.7}{sub -1.6} x 10{sup -3} eV, and one Majorana phase, {alpha}{sub 21}/{pi}=1.0{sup +0.2}{sub -0.2}. (orig.)
International Nuclear Information System (INIS)
Close, F.E.
1976-01-01
The studies of inelastic electron scattering at SLAC and of neutrino scattering at CERN have been widely interpreted as giving support to the idea that the nucleon is built from elementary constituents, called partons, and that these partons have the same quantum numbers as the quarks that are familiar in spectroscopy. In particular, a very simple regularity in the data, known as scale invariance or just 'scaling' was seen at least at moderate energies (2 2 > approximately 1 GeV) which is natural in the parton model. The data on e + e - annihilation also appear to be consistent with scaling when Esub(cm) approximately 5 GeV. These lectures are concerned with the scaling phenomena. One may expect the new hadronic degree of freedom to generate scaling violations in inelastic electron and neutrino scattering. These are mentioned briefly in these lectures. (Auth.)
Quark mass correction to chiral separation effect and pseudoscalar condensate
Energy Technology Data Exchange (ETDEWEB)
Guo, Er-dong [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190 (China); Kavli Institute of Theoretical Physics China, Chinese Academy of Sciences,Beijing 100190 (China); Lin, Shu [School of Physics and Astronomy, Sun Yat-Sen University,No 2 University Road, Zhuhai 519082 (China)
2017-01-25
We derived an analytic structure of the quark mass correction to chiral separation effect (CSE) in small mass regime. We confirmed this structure by a D3/D7 holographic model study in a finite density, finite magnetic field background. The quark mass correction to CSE can be related to correlators of pseudo-scalar condensate, quark number density and quark condensate in static limit. We found scaling relations of these correlators with spatial momentum in the small momentum regime. They characterize medium responses to electric field, inhomogeneous quark mass and chiral shift. Beyond the small momentum regime, we found existence of normalizable mode, which possibly leads to formation of spiral phase. The normalizable mode exists beyond a critical magnetic field, whose magnitude decreases with quark chemical potential.
Asymptotics of pion electromagnetics form factor in scale invariant quark model
International Nuclear Information System (INIS)
Efremov, A.V.; Radyushkin, A.V.
1976-01-01
A consistent relativistic approach is proposed to the investigation of asymptotic behaviour of form factor of a system, composed of two spinor particles, interacting with the vector of (pseudo) scalar neutral field. It is shown that the assumption of finite and small asymptotical value of quark-gluon interaction invariant charge at small distances (g 9 2 9 2 ln(-Q 2 ) 2 values (Q 2 is squared momentum)
Top-Quark p(T) - Spectra at CMS and Flavor Independence of z - Scaling
Czech Academy of Sciences Publication Activity Database
Tokarev, M. V.; Zborovský, Imrich
2017-01-01
Roč. 14, č. 5 (2017), s. 681-686 ISSN 1547-4771 R&D Projects: GA MŠk(CZ) LG15052 Institutional support: RVO:61389005 Keywords : high energy * proton-proton collisions * self-similarity * top quark spectra Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
International Nuclear Information System (INIS)
Volkov, D.V.; Zheltukhin, A.A.; Pashnev, A.I.
1975-01-01
As it has shown, the study of vacuum transitions in dual models makes it possible to establish certain relations between duality, on the one hand, and the quark structure of resonances and the internal symmetries, on the other. In the case of Veneziano model the corresponding quark structure of resonances is determined by the infinity number of quarks of increasing mass. The intercents of the main trajectory and all adopted trajectories are additive with respect to squares of mass-forming quarks. The latter circumstance results in a number of important consequences: the presence of quadratic mass formulas for resonance states; the exact SU(infinity)-symmetry for the three-resonance coupling constants; the validity of Adler's self-consistency principle for external particles composed of different quarks and anti-quarks, etc
Reynolds number scaling of straining motions in turbulence
Elsinga, Gerrit; Ishihara, T.; Goudar, M. V.; da Silva, C. B.; Hunt, J. C. R.
2017-11-01
Strain is an important fluid motion in turbulence as it is associated with the kinetic energy dissipation rate, vorticity stretching, and the dispersion of passive scalars. The present study investigates the scaling of the turbulent straining motions by evaluating the flow in the eigenframe of the local strain-rate tensor. The analysis is based on DNS of homogeneous isotropic turbulence covering a Reynolds number range Reλ = 34.6 - 1131. The resulting flow pattern reveals a shear layer containing tube-like vortices and a dissipation sheet, which both scale on the Kolmogorov length scale, η. The vorticity stretching motions scale on the Taylor length scale, while the flow outside the shear layer scales on the integral length scale. These scaling results are consistent with those in wall-bounded flow, which suggests a quantitative universality between the different flows. The overall coherence length of the vorticity is 120 η in all directions, which is considerably larger than the typical size of individual vortices, and reflects the importance of spatial organization at the small scales. Transitions in flow structure are identified at Reλ 45 and 250. Below these respective Reynolds numbers, the small-scale motions and the vorticity stretching motions appear underdeveloped.
A Chain Perspective on Large-scale Number Systems
Grijpink, J.H.A.M.
2012-01-01
As large-scale number systems gain significance in social and economic life (electronic communication, remote electronic authentication), the correct functioning and the integrity of public number systems take on crucial importance. They are needed to uniquely indicate people, objects or phenomena
Small-scale dynamo at low magnetic Prandtl numbers
Schober, Jennifer; Schleicher, Dominik; Bovino, Stefano; Klessen, Ralf S.
2012-12-01
The present-day Universe is highly magnetized, even though the first magnetic seed fields were most probably extremely weak. To explain the growth of the magnetic field strength over many orders of magnitude, fast amplification processes need to operate. The most efficient mechanism known today is the small-scale dynamo, which converts turbulent kinetic energy into magnetic energy leading to an exponential growth of the magnetic field. The efficiency of the dynamo depends on the type of turbulence indicated by the slope of the turbulence spectrum v(ℓ)∝ℓϑ, where v(ℓ) is the eddy velocity at a scale ℓ. We explore turbulent spectra ranging from incompressible Kolmogorov turbulence with ϑ=1/3 to highly compressible Burgers turbulence with ϑ=1/2. In this work, we analyze the properties of the small-scale dynamo for low magnetic Prandtl numbers Pm, which denotes the ratio of the magnetic Reynolds number, Rm, to the hydrodynamical one, Re. We solve the Kazantsev equation, which describes the evolution of the small-scale magnetic field, using the WKB approximation. In the limit of low magnetic Prandtl numbers, the growth rate is proportional to Rm(1-ϑ)/(1+ϑ). We furthermore discuss the critical magnetic Reynolds number Rmcrit, which is required for small-scale dynamo action. The value of Rmcrit is roughly 100 for Kolmogorov turbulence and 2700 for Burgers. Furthermore, we discuss that Rmcrit provides a stronger constraint in the limit of low Pm than it does for large Pm. We conclude that the small-scale dynamo can operate in the regime of low magnetic Prandtl numbers if the magnetic Reynolds number is large enough. Thus, the magnetic field amplification on small scales can take place in a broad range of physical environments and amplify week magnetic seed fields on short time scales.
Small-scale dynamo at low magnetic Prandtl numbers.
Schober, Jennifer; Schleicher, Dominik; Bovino, Stefano; Klessen, Ralf S
2012-12-01
The present-day Universe is highly magnetized, even though the first magnetic seed fields were most probably extremely weak. To explain the growth of the magnetic field strength over many orders of magnitude, fast amplification processes need to operate. The most efficient mechanism known today is the small-scale dynamo, which converts turbulent kinetic energy into magnetic energy leading to an exponential growth of the magnetic field. The efficiency of the dynamo depends on the type of turbulence indicated by the slope of the turbulence spectrum v(ℓ)∝ℓ^{ϑ}, where v(ℓ) is the eddy velocity at a scale ℓ. We explore turbulent spectra ranging from incompressible Kolmogorov turbulence with ϑ=1/3 to highly compressible Burgers turbulence with ϑ=1/2. In this work, we analyze the properties of the small-scale dynamo for low magnetic Prandtl numbers Pm, which denotes the ratio of the magnetic Reynolds number, Rm, to the hydrodynamical one, Re. We solve the Kazantsev equation, which describes the evolution of the small-scale magnetic field, using the WKB approximation. In the limit of low magnetic Prandtl numbers, the growth rate is proportional to Rm^{(1-ϑ)/(1+ϑ)}. We furthermore discuss the critical magnetic Reynolds number Rm_{crit}, which is required for small-scale dynamo action. The value of Rm_{crit} is roughly 100 for Kolmogorov turbulence and 2700 for Burgers. Furthermore, we discuss that Rm_{crit} provides a stronger constraint in the limit of low Pm than it does for large Pm. We conclude that the small-scale dynamo can operate in the regime of low magnetic Prandtl numbers if the magnetic Reynolds number is large enough. Thus, the magnetic field amplification on small scales can take place in a broad range of physical environments and amplify week magnetic seed fields on short time scales.
International Nuclear Information System (INIS)
Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Anderson, M.; Arkhipkin, D.; Averichev, G.S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Bhardwaj, S.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L.C.; Blyth, S.-L.; Bonner, B.E.; Botje, M.; Bouchet, J.; Brandin, A.V.; Bravar, A.; Bystersky, M.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Castillo, J.; Catu, O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cosentino, M.R.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Daugherity, M.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S.M.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dunin, V.B.; Dunlop, J.C.; Dutta Mazumdar, M.R.; Eckardt, V.; Edwards, W.R.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Ganti, M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.S.; Gorbunov, Y.G.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guimaraes, K.S.F.F.; Guo, Y.; Gupta, N.; Gutierrez, T.D.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Henry, T.W.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Horner, M.J.; Huang, H.Z.; Huang, S.L.; Hughes, E.W.; Humanic, T.J.; Igo, G.; Jacobs, P.; Jacobs, W.W.; Jakl, P.; Jia, F.; Jiang, H.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev, V.Yu.; Kim, B.C.; Kiryluk, J.; Kisiel, A.; Kislov, E.M.; Klein, S.R.; Kocoloski, A.; Koetke, D.D.
2007-01-01
We present STAR measurements of the azimuthal anisotropy parameter v 2 for pions, kaons, protons, Lambda, bar Lambda, Xi+bar Xi,and Omega + bar Omega, along with v 4 for pions, kaons, protons, and Lambda + bar Lambda at mid-rapidity for Au+Au collisions at sqrt sNN=62.4and 200 GeV. The v 2 (p T ) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, v 2 values at 62.4, 130, and 200 GeV are as little as 10 percent-15 percent larger than those in Pb+Pb collisions at sqrt s NN=17.3 GeV. At intermediate transverse momentum (p T from 1.5-5 GeV/c),the 62.4 GeV v 2 (p T ) and v 4 (p T ) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the non-flow contributions to pions and protons and some indications are found for a smaller non-flow contribution to protons than pions. Baryon v 2 is larger than anti-baryon v 2 at 62.4 and 200 GeV perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to mid-rapidity enhances v 2 , or that anti-baryon and baryon annihilation is larger in the in-plane direction
Jet energy scale corrections and their impact on measurements of the top-quark mass at CMS
International Nuclear Information System (INIS)
Kirschenmann, Henning
2014-10-01
The final state of many physics processes at the Large Hadron Collider (LHC) is dominated by jets, the experimental signature of quarks and gluons. The precise measurement of jets is a prerequisite to understand these processes. In this thesis, the determination of jet-energy corrections at CMS using dijet events is described, and the investigation of a correction specifically tailored to improve the reconstruction of b-jets in top-quark mass measurements is presented. Dijet events are used to determine the response relative to the central detector region in data and simulation as a function of the pseudorapidity η. Two complementary response estimators are introduced and detailed supplementary studies, e.g. of the time stability of the response, are performed. For the 2011 data-taking period, the MC/Data differences are found to be below 5% in the tracker-covered detector region with systematic uncertainties of less than 1%. Furthermore, a study of b-jet properties in 2012 data is presented. The correlation of various such observables with the response is exploited to improve the jet-energy measurement of b-jets. A resolution improvement of about 10% can be achieved, and the evaluation of b-jet specific jet-energy scale uncertainties (b-JES) indicates improvements of about 30%. This additional correction is applied to an existing measurement of the top-quark mass in the muon+jets channel. It leads to a statistical sensitivity improvement of about 10% and a reduction of systematic uncertainties related to the b-JES from 0.6 GeV to 0.3 GeV.
Laenen, E.
2012-01-01
The theoretical aspects of a number of top quark properties such as its mass and its couplings are reviewed. Essential aspects in the theoretical description of top quark production, singly, in pairs and in association, as well as its decay related to spin and angular correlations are discussed.
Experimental constraint on quark electric dipole moments
Liu, Tianbo; Zhao, Zhiwen; Gao, Haiyan
2018-04-01
The electric dipole moments (EDMs) of nucleons are sensitive probes of additional C P violation sources beyond the standard model to account for the baryon number asymmetry of the universe. As a fundamental quantity of the nucleon structure, tensor charge is also a bridge that relates nucleon EDMs to quark EDMs. With a combination of nucleon EDM measurements and tensor charge extractions, we investigate the experimental constraint on quark EDMs, and its sensitivity to C P violation sources from new physics beyond the electroweak scale. We obtain the current limits on quark EDMs as 1.27 ×10-24 e .cm for the up quark and 1.17 ×10-24 e .cm for the down quark at the scale of 4 GeV2 . We also study the impact of future nucleon EDM and tensor charge measurements, and show that upcoming new experiments will improve the constraint on quark EDMs by about 3 orders of magnitude leading to a much more sensitive probe of new physics models.
International Nuclear Information System (INIS)
Kerman, A.K.
1981-01-01
This short talk gives some very general comments on what I see as the impact on nuclear physics of the last ten years' developments in the picture of the nucleon and the hadron. On the other hand there may also be some nuclear physics lessons - lessons we've learned by trying to deal with the multi-fermion system over a long period - and I will discuss what those lessons might be for the problem at hand, hadron phy-physics up to 31 GeV. After that I will discuss a number of implications of quarks for low energy physics
Diffractive dissociation and new quarks
International Nuclear Information System (INIS)
White, A.R.
1983-04-01
We argue that the chiral limit of QCD can be identified with the strong (diffractive dissociation) coupling limit of reggeon field theory. Critical Pomeron scaling at high energy must then be directly related to an infra-red fixed-point of massless QCD and so requires a large number of flavors. This gives a direct argument that the emergence of diffraction-peak scaling, KNO scaling etc. at anti p-p colliders are evidence of a substantial quark structure still to be discovered
Coordinated scaling of cortical and cerebellar numbers of neurons
Directory of Open Access Journals (Sweden)
Suzana Herculano-Houzel
2010-03-01
Full Text Available While larger brains possess concertedly larger cerebral cortices and cerebella, the relative size of the cerebral cortex increases with brain size, but relative cerebellar size does not. In the absence of data on numbers of neurons in these structures, this discrepancy has been used to dispute the hypothesis that the cerebral cortex and cerebellum function and have evolved in concert and to support a trend towards neocorticalization in evolution. However, the rationale for interpreting changes in absolute and relative size of the cerebral cortex and cerebellum relies on the assumption that they reflect absolute and relative numbers of neurons in these structures across all species – an assumption that our recent studies have shown to be flawed. Here I show for the first time that the numbers of neurons in the cerebral cortex and cerebellum are directly correlated across 19 mammalian species of 4 different orders, including humans, and increase concertedly in a similar fashion both within and across the orders Eulipotyphla (Insectivora, Rodentia, Scandentia and Primata, such that on average a ratio of 3.6 neurons in the cerebellum to every neuron in the cerebral cortex is maintained across species. This coordinated scaling of cortical and cerebellar numbers of neurons provides direct evidence in favor of concerted function, scaling and evolution of these brain structures, and suggests that the common notion that equates cognitive advancement with neocortical expansion should be revisited to consider in its stead the coordinated scaling of neocortex and cerebellum as a functional ensemble.
Direct Numerical Simulation of Low Capillary Number Pore Scale Flows
Esmaeilzadeh, S.; Soulaine, C.; Tchelepi, H.
2017-12-01
The arrangement of void spaces and the granular structure of a porous medium determines multiple macroscopic properties of the rock such as porosity, capillary pressure, and relative permeability. Therefore, it is important to study the microscopic structure of the reservoir pores and understand the dynamics of fluid displacements through them. One approach for doing this, is direct numerical simulation of pore-scale flow that requires a robust numerical tool for prediction of fluid dynamics and a detailed understanding of the physical processes occurring at the pore-scale. In pore scale flows with a low capillary number, Eulerian multiphase methods are well-known to produce additional vorticity close to the interface. This is mainly due to discretization errors which lead to an imbalance of capillary pressure and surface tension forces that causes unphysical spurious currents. At the pore scale, these spurious currents can become significantly stronger than the average velocity in the phases, and lead to unphysical displacement of the interface. In this work, we first investigate the capability of the algebraic Volume of Fluid (VOF) method in OpenFOAM for low capillary number pore scale flow simulations. Afterward, we compare VOF results with a Coupled Level-Set Volume of Fluid (CLSVOF) method and Iso-Advector method. It has been shown that the former one reduces the VOF's unphysical spurious currents in some cases, and both are known to capture interfaces sharper than VOF. As the conclusion, we will investigate that whether the use of CLSVOF or Iso-Advector will lead to less spurious velocities and more accurate results for capillary driven pore-scale multiphase flows or not. Keywords: Pore-scale multiphase flow, Capillary driven flows, Spurious currents, OpenFOAM
Dependency on scale of power numbers of Rushton disc turbines
Energy Technology Data Exchange (ETDEWEB)
Bujalski, W.; Nienow, A.W.; Chatwin, S.; Cooke, M.
1987-01-01
Extensive and very accurate power numbers have been obtained for a wide range of Rushton disc turbines using water as the working fluid in six fully baffled vessels from 0.22 to 1.83 m diameter. The results show that for Reynolds numbers greater than or equal to 2 x 10/sup 4/, the average peak power number anti Po is dependent on the disc thickness (x/sub 1/) to impeller diameter (D) ratio and to the vessel diameter (T). Provided x/sub 1//D is constant, anti Po is independent of impeller to vessel ratio in the range 0.25 less than or equal to D/T less than or equal to 0.70. For 0.01 less than or equal to x/sub 1//D less than or equal to 0.05 and for the range of vessels studied, the equation anti Po = 2.5(x/sub 1//D)/sup -0.2/ (T/T/sub 0/)/sup 0.065/ fitted the data to within +/- 3% where T/sub 0/ is a 1 m diameter vessel. An F-test shows that the inclusion of the small effect of scale, (T/T/sub 0/), is statistically significant at the 99% level. The implications of these scale and geometrical effects for mixing research, process design and scale-up are discussed.
arXiv Top Quark Mass Measurements at the LHC
AUTHOR|(INSPIRE)INSPIRE-00220136
2016-01-01
The top quark mass ($m_{top}$) is a fundamental parameter of the Standard Model of Particle Physics (SM). As the heaviest of all SM particles with a mass close to the electroweak symmetry-breaking scale, the top quark plays a pivotal role in the theory of elementary particles. The exact value of the top quark mass has implications on a number of theoretical predictions, which motivates the need for precision measurements of $m_{top}$. This document highlights a number of such measurements carried out by the ATLAS and CMS collaborations based on the combined LHC Run 1 datasets at centre-of-mass energies of $\\sqrt{s}=7$ and $8$ TeV. A wide range of analysis strategies are employed for a number of final-state signatures. Measurements of both the top quark pole mass as well as the value of $m_{top}$ as defined by the Monte Carlo generator in simulated signal samples are discussed.
Study of stellar objects with strange quark matter crust
International Nuclear Information System (INIS)
Hothi, N.; Bisht, S.
2012-01-01
The absolute stability of strange quark matter is a viable possibility and immensely effects physics at the astrophysical scale. Relativistic heavy-ion reactions offer a stage to produce this exotic state of matter and the enhanced production of strange particles during these reactions can be studied within the framework of quark-gluon plasma (QGP). We have tried to investigate the role of strangeness under the compact star phenomenology. Emphasis is laid upon the possibility of existence of a third family of strange quark stars and its study help in revealing a number of unexplored features of the cosmos. Bag model parameters have been used to determine some integral parameters for a sequence of strange stars with crust and strange dwarfs constructed out of strange quark matter crust. A comparative analysis is performed between the strange and neutron stars and the strange and white dwarfs based upon these intrinsic parameters and paramount differences are observed. The intimacy between astrophysics and strange quarks depends strongly upon the strange quark matter hypothesis. It states that for a collection of more than a few hundred u, d and s quarks, the energy per baryon E/A of strange quark matter (SQM) can be well below the energy per baryon of the most stable atomic nuclei
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
Scale breaking effects in the quark-parton model for large P perpendicular phenomena
International Nuclear Information System (INIS)
Baier, R.; Petersson, B.
1977-01-01
We discuss how the scaling violations suggested by an asymptotically free parton model, i.e., the Q 2 -dependence of the transverse momentum of partons within hadrons may affect the parton model description of large p perpendicular phenomena. We show that such a mechanism can provide an explanation for the magnitude of the opposite side correlations and their dependence on the trigger momentum. (author)
On the difference between the pole and the MS masses of the top quark at the electroweak scale
Energy Technology Data Exchange (ETDEWEB)
Jegerlehner, Fred [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Kalmykov, Mikhail Yu.; Kniehl, Bernd A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2012-12-15
We argue that for a Higgs boson mass M{sub H} {proportional_to} 125 GeV, as estimated from recent Higgs searches at the LHC, the inclusion of the electroweak radiative corrections in the relationship between the pole and MS masses of the top quark reduces the difference to about 1 GeV. This fact is relevant for the scheme dependence of electroweak observables as well as for the extraction of the top quark mass from experimental data.
Compound quarks and gluons and parton confinement (proposal of a different approach)
International Nuclear Information System (INIS)
Krolikowski, W.
1978-01-01
The author develops further the compound model proposed in 1971, where coloured quarks are factorized into elementary constituents carrying separately the flavour and colour quantum numbers and obeying the 'compensating' wrong statistics. An 'effective quantum chromodynamics' is conjectured, where both coloured quarks and vector gluons (which obey good statistics) are factorized into elementary constituents obeying wrong statistics. Then the Pauli connection of spin and statistics confines these elementary constituents within bound states obeying good statistics. In the parton model approximation with these elementary constituents as partons it prevents also coloured quarks and vector gluons from appearing as free particles. The expected confinement violation for coloured quarks and vector gluons and the observed scaling violation have here a common origin, namely the clustering of elementary constituents inside hadrons. The basic difference between leptons and quarks is related in this model to wrong statistics of elementary constituents involved in the quark structure. (Auth.)
International Nuclear Information System (INIS)
Anon.
1987-01-01
Quarks are understood to interact through the 'colour' force, carried by gluons. Under normal conditions these quarks are confined - frozen together in 'colourless' states such as protons, neutrons and other strongly interacting particles. However if the quarks are compressed tightly together and/or are 'heated' by increasing their energy, they should eventually break loose from their colour bonds to form a new kind of matter – the so-called quark-gluon plasma. Although QGP has not yet been synthesized in the Laboratory, it was most likely the stuff of the Universe 10 -5 second after the Big Bang. Thus the search for this 'new' matter is attracting a growing number of physicists, theorists and experimenters from both the particle physics and nuclear physics fields
International Nuclear Information System (INIS)
Joos, H.
1976-07-01
The main topics of these lectures are: phenomenological approach to quark confinement, standard Lagrangian of hadrondynamics, Lagrangian field theory and quark confinement, classical soliton solutions in a simple model, quantization of extended systems, colour charge screening and quantization on a lattice and remarks on applications. A survey of the scientific publications listed according to the topics until 26 March 1976 is supplemented. (BJ) [de
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
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
Quark fragmentation function and the nonlinear chiral quark model
International Nuclear Information System (INIS)
Zhu, Z.K.
1993-01-01
The scaling law of the fragmentation function has been proved in this paper. With that, we show that low-P T quark fragmentation function can be studied as a low energy physocs in the light-cone coordinate frame. We therefore use the nonlinear chiral quark model which is able to study the low energy physics under scale Λ CSB to study such a function. Meanwhile the formalism for studying the quark fragmentation function has been established. The nonlinear chiral quark model is quantized on the light-front. We then use old-fashioned perturbation theory to study the quark fragmentation function. Our first order result for such a function shows in agreement with the phenomenological model study of e + e - jet. The probability for u,d pair formation in the e + e - jet from our calculation is also in agreement with the phenomenological model results
Numbers, scale and symbols: the public understanding of nanotechnology
International Nuclear Information System (INIS)
Batt, Carl A.; Waldron, Anna M.; Broadwater, Natalie
2008-01-01
Nanotechnology will be an increasing part of the everyday lives of most people in the world. There is a general recognition that few people understand the implications of the technology, the technology itself or even the definition of the word. This lack of understanding stems from a lack of knowledge about science in general but more specifically difficulty in grasping the size scale and symbolism of nanotechnology. A potential key to informing the general public is establishing the ability to comprehend the scale of nanotechnology. Transitioning from the macro to the nanoscale seems to require an ability to comprehend scales of one-billion. Scaling is a skill not common in most individuals and tests of their ability to extrapolate size based upon scaling a common object demonstrates that most individuals cannot scale to the extent needed to make the transition to nanoscale. Symbolism is another important vehicle to providing the general public with a basis to understand the concepts of nanotechnology. With increasing age, individuals are able to draw representations of atomic scale objects, but these tend to be iconic and the different representations not easily translated. Ball and stick models are most recognized by the public, which provides an opportunity to present not only useful symbolism but also a reference point for the atomic scale.
Numbers, scale and symbols: the public understanding of nanotechnology
Batt, Carl A.; Waldron, Anna M.; Broadwater, Natalie
2008-10-01
Nanotechnology will be an increasing part of the everyday lives of most people in the world. There is a general recognition that few people understand the implications of the technology, the technology itself or even the definition of the word. This lack of understanding stems from a lack of knowledge about science in general but more specifically difficulty in grasping the size scale and symbolism of nanotechnology. A potential key to informing the general public is establishing the ability to comprehend the scale of nanotechnology. Transitioning from the macro to the nanoscale seems to require an ability to comprehend scales of one-billion. Scaling is a skill not common in most individuals and tests of their ability to extrapolate size based upon scaling a common object demonstrates that most individuals cannot scale to the extent needed to make the transition to nanoscale. Symbolism is another important vehicle to providing the general public with a basis to understand the concepts of nanotechnology. With increasing age, individuals are able to draw representations of atomic scale objects, but these tend to be iconic and the different representations not easily translated. Ball and stick models are most recognized by the public, which provides an opportunity to present not only useful symbolism but also a reference point for the atomic scale.
Indian Academy of Sciences (India)
eter for the tests of the electroweak theory, since radiative corrections to many ... The uncertainty due to jet energy scale (JES) is the dominating systematic .... In the Standard Model, the charge of the top quark is predicted to be that of a normal up- ..... non-negative and f+ + f0 < 1, and the star marks the expectation from the ...
Bootstrapping quarks and gluons
Energy Technology Data Exchange (ETDEWEB)
Chew, G.F.
1979-04-01
Dual topological unitarization (DTU) - the approach to S-matrix causality and unitarity through combinatorial topology - is reviewed. Amplitudes associated with triangulated spheres are shown to constitute the core of particle physics. Each sphere is covered by triangulated disc faces corresponding to hadrons. The leading current candidate for the hadron-face triangulation pattern employs 3-triangle basic subdiscs whose orientations correspond to baryon number and topological color. Additional peripheral triangles lie along the hadron-face perimeter. Certain combinations of peripheral triangles with a basic-disc triangle can be identified as quarks, the flavor of a quark corresponding to the orientation of its edges that lie on the hadron-face perimeter. Both baryon number and flavor are additively conserved. Quark helicity, which can be associated with triangle-interior orientation, is not uniformly conserved and interacts with particle momentum, whereas flavor does not. Three different colors attach to the 3 quarks associated with a single basic subdisc, but there is no additive physical conservation law associated with color. There is interplay between color and quark helicity. In hadron faces with more than one basic subdisc, there may occur pairs of adjacent flavorless but colored triangles with net helicity +-1 that are identifiable as gluons. Broken symmetry is an automatic feature of the bootstrap. T, C and P symmetries, as well as up-down flavor symmetry, persist on all orientable surfaces.
Bootstrapping quarks and gluons
International Nuclear Information System (INIS)
Chew, G.F.
1979-04-01
Dual topological unitarization (DTU) - the approach to S-matrix causality and unitarity through combinatorial topology - is reviewed. Amplitudes associated with triangulated spheres are shown to constitute the core of particle physics. Each sphere is covered by triangulated disc faces corresponding to hadrons. The leading current candidate for the hadron-face triangulation pattern employs 3-triangle basic subdiscs whose orientations correspond to baryon number and topological color. Additional peripheral triangles lie along the hadron-face perimeter. Certain combinations of peripheral triangles with a basic-disc triangle can be identified as quarks, the flavor of a quark corresponding to the orientation of its edges that lie on the hadron-face perimeter. Both baryon number and flavor are additively conserved. Quark helicity, which can be associated with triangle-interior orientation, is not uniformly conserved and interacts with particle momentum, whereas flavor does not. Three different colors attach to the 3 quarks associated with a single basic subdisc, but there is no additive physical conservation law associated with color. There is interplay between color and quark helicity. In hadron faces with more than one basic subdisc, there may occur pairs of adjacent flavorless but colored triangles with net helicity +-1 that are identifiable as gluons. Broken symmetry is an automatic feature of the bootstrap. T, C and P symmetries, as well as up-down flavor symmetry, persist on all orientable surfaces
International Nuclear Information System (INIS)
Lipkin, H.J.
1980-09-01
Quark-lepton unification is examined without assuming higher symmetries on more general gauge theories. In particular, properties are sought which are generally attributed to SU(5) models which are already present without the assumption of SU(5)
Quark chemistry: charmonium molecules
International Nuclear Information System (INIS)
De Rujula, A.; Jaffe, R.L.
1977-01-01
The theoretical and experimental evidence for two quark-two antiquark hadrons is reviewed. Concentration is placed on predictions for S-wave ''charmonium molecules,'' built of a c anti c charmonium pair and a light quark-antiquark pair. Their spectrum and quantum numbers are predicted and an estimate of their decay couplings and their prediction in monochromatic pion decays from charmonium resonances produced in e + e - -annihilation is given. Some S-wave charmonium resonances should be detectable in these decays, but typical branching ratios are only at the 1% level. 19 references
International Nuclear Information System (INIS)
Anon.
1981-01-01
In spite of (or perhaps because of) the present doctrine of total quark confinement held by the majority of particle theorists, experimental searches for free fractional charge and other anomalous stable particles in ordinary matter have been increasing in number during recent years, using a range of techniques of increasing sophistication and sensitivity. As a result, researchers in this area had a conference to themselves in June. About 40 participants and 150 observers gathered at San Francisco State University to report progress and discuss future plans, with representatives present from almost every group involved in quark searches
Indian Academy of Sciences (India)
2012-10-04
Oct 4, 2012 ... The theoretical aspects of a number of top quark properties such as ... to the quadratic divergences of the Higgs self-energy, while yet, ..... given in the literature, each with the aim of recovering a well-behaved expansion in αs.
Reynolds Number Scaling and Parameterization of Stratified Turbulent Wakes
2017-04-17
be solved numerically. These issues are the focal point of our current investigations. The most recent update on our work on high Re effects in...Reynolds numbers, internal waves, nonlinear effects , mean flows, Lagrangian dispersion. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT... location where nonlinear dynamics and, therefore, Lagrangian mean drift are most potent. An extensive existing database of 19 2-D simulations of
Mapping copy number variation by population-scale genome sequencing
DEFF Research Database (Denmark)
Mills, Ryan E.; Walter, Klaudia; Stewart, Chip
2011-01-01
Genomic structural variants (SVs) are abundant in humans, differing from other forms of variation in extent, origin and functional impact. Despite progress in SV characterization, the nucleotide resolution architecture of most SVs remains unknown. We constructed a map of unbalanced SVs (that is......, copy number variants) based on whole genome DNA sequencing data from 185 human genomes, integrating evidence from complementary SV discovery approaches with extensive experimental validations. Our map encompassed 22,025 deletions and 6,000 additional SVs, including insertions and tandem duplications...
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.)
Top Quark Mass Measurements at ATLAS and CMS
McCarthy, Tom; The ATLAS collaboration
2016-01-01
The top quark mass ($m_{top}$) is a fundamental parameter of the Standard Model of Particle Physics (SM). As the heaviest of all known SM particles with a mass close to the EW symmetry breaking scale, the top quark plays a pivotal role in the theory of elementary particles. The exact value of the top quark mass has implications on a number of theoretical predictions, which motivates the need for precision measurements of $m_{top}$. This presentation highlights a number of such precision measurements carried out by the ATLAS and CMS collaborations at centre-of-mass energies of $\\sqrt{s}=7$ and $8$ TeV from the combined LHC Run I datasets. A wide range of analysis strategies are employed in a number of channels. Measurements of both the top quark pole mass and $m_{top}$ as defined by the Monte Carlo generator in simulated signal samples are shown. Finally, a summary of combinations of the LHC measurements is presented, together with a look toward top quark mass measurements at $\\sqrt{s}=13$ TeV.
Quarks as quasiparticles of bound states
International Nuclear Information System (INIS)
Tyapkin, A.A.
1977-01-01
Interpretation of quarks as strongly bound subsystems of the baryon structure, being in various states with integer the quantum numbers Q and B, is considered. Three original quark states, distinguished by Q, B, and J, are unambiguously determined from the condition that the quarks have the corresponding fractional quantum numbers while the integer quantum numbers for the whole system are known. With this in view the new quantum number ''colour'' is interpreted as a quantity, specifying the appearance of the subsystems in various eigen-states. Basing on the generalized Sakata model, the self-consistency of change of the colour states in the three-quark system is explained
''Follow that quark!'' (and other exclusive stories)
International Nuclear Information System (INIS)
Carroll, A.S.
1987-01-01
Quarks are considered to be the basic constituents of matter. In a series of recent experiments, Carroll studied exclusive reactions as a means of determining the interactions between quarks. Quantum Chromo-dynamics (QCD) is the modern theory of the interaction of quarks. This theory explains how quarks are held together via the strong interaction in particles known as hadrons. Hadrons consisting of three quarks are called baryons. Hadrons made up of a quark and an antiquark are called mesons. In his lecture, Carroll describes what happens when two hadrons collide and scatter to large angles. The violence of the collision causes the gluons that bind the quarks in a particular hadron to temporarily lose their grip on particular quarks. Quarks scramble toward renewed unity with other quarks, and they undergo rearrangement, which generally results in additional new particles. A two-body exclusive reaction has occurred when the same number of particles exist before and after the collisions. At large angles these exclusive reactions are very rare. The labels on the quarks known as flavor enable the experimenter to follow the history of individual quarks in detail during these exclusive reactions. Carroll describes the equipment used in the experiment to measure short distance, hard collisions at large angles. The collisions he discusses occur when a known beam of mesons or protons collide with a stationary proton target. Finally, Carroll summarizes what the experiments have shown from the study of exclusive reactions and what light some of their results shed on the theory of QCD
Sextet quarks and light pseudoscalars
International Nuclear Information System (INIS)
Clark, T.E.; Leung, C.N.; Love, S.T.; Rosner, J.L.; Chicago Univ., IL
1986-01-01
Light pseudoscalar bosons are a very general consequence of the existence of higher-color representations (such as sextets) of quarks. It is shown that if the condensate vertical stroke vertical stroke=F 3 defines a scale F>>Λ QCD , as has been expected on the basis of perturbative and lattice calculations, then present limits on axions exclude a wide range of values of F. Such limits therefore serve as complements to direct accelerator searches for higher-color quarks. (orig.)
International Nuclear Information System (INIS)
Maki, Tuula; Helsinki Inst. of Phys.; Helsinki U. of Tech.
2008-01-01
The top quark is the heaviest elementary particle. Its mass is one of the fundamental parameters of the standard model of particle physics, and an important input to precision electroweak tests. This thesis describes three measurements of the top-quark mass in the dilepton decay channel. The dilepton events have two neutrinos in the final state; neutrinos are weakly interacting particles that cannot be detected with a multipurpose experiment. Therefore, the signal of dilepton events consists of a large amount of missing energy and momentum carried off by the neutrinos. The top-quark mass is reconstructed for each event by assuming an additional constraint from a top mass independent distribution. Template distributions are constructed from simulated samples of signal and background events, and parameterized to form continuous probability density functions. The final top-quark mass is derived using a likelihood fit to compare the reconstructed top mass distribution from data to the parameterized templates. One of the analyses uses a novel technique to add top mass information from the observed number of events by including a cross-section-constraint in the likelihood function. All measurements use data samples collected by the CDF II detector
The conventional quark picture
International Nuclear Information System (INIS)
Dalitz, R.H.
1976-01-01
For baryons, mesons and deep inelastic phenomena the ideas and the problems of the conventional quark picture are pointed out. All observed baryons fit in three SU(3)-multiplets which cluster into larger SU(6)-multiplets. No mesons are known which have quantum numbers inconsistent with belonging to a SU(3) nonet or octet. The deep inelastic phenomena are described in terms of six structure functions of the proton. (BJ) [de
On the ultimate uncertainty of the top quark pole mass
Beneke, M.; Marquard, P.; Nason, P.; Steinhauser, M.
2017-12-01
We combine the known asymptotic behaviour of the QCD perturbation series expansion, which relates the pole mass of a heavy quark to the MS ‾ mass, with the exact series coefficients up to the four-loop order to determine the ultimate uncertainty of the top-quark pole mass due to the renormalon divergence. We perform extensive tests of our procedure by varying the number of colours and flavours, as well as the scale of the strong coupling and the MS ‾ mass. Including an estimate of the internal bottom and charm quark mass effect, we conclude that this uncertainty is around 110 MeV. We further estimate the additional contribution to the mass relation from the five-loop correction and beyond to be around 300 MeV.
Validation of the flux number as scaling parameter for top-spray fluidised bed systems
DEFF Research Database (Denmark)
Hede, Peter Dybdahl; Bach, P.; Jensen, Anker Degn
2008-01-01
2SO4 using Dextrin as binder in three top-spray fluidised bed scales, i.e. a small-scale (type: GEA Aeromatic-Fielder Strea-1), medium-scale (type: Niro MP-1) and large-scale (type: GEA MP-2/3). Following the parameter guidelines adapted from the original patent description, the flux number....... Coating conditions with flux number values of 4.5 and 4.7 were however successful in terms of agglomeration tendency and match of particle size fractions, but indicated in addition a strong influence of nozzle pressure. The present paper suggests even narrower boundaries for the flux number compared...
International Nuclear Information System (INIS)
Nambu, J.
1978-01-01
Three quark models of hadron structure, which suggest an explanation of quarks confinement mechanism in hadrons are considered. Quark classifications, quark flawors and colours, symmetry model of hadron structure based on the colour theory of strong interaction are discussed. Diagrams of colour combinations of quarks and antiquarks, exchange of gluons, binding quarks in hadron. Quark confinement models based on the field theory, string model rotating and bag model are discussed. Diagrams of the colour charge distribution explaining the phenomena of infrared ''slavery'' and ultraviolet ''freedom'' are given. The models considered explain but some quark properties, creating prerequisites for the development of the consequent theory of hadron structure
Top quark physics in ATLAS (CORFU 2014)
Moreno Llácer, M; The ATLAS collaboration
2014-01-01
The top quark is the heaviest elementary particle observed to date. Being heavier than a W boson, it is the only quark that decays weakly, i.e. into a real W boson and a b quark, before hadronization can occur. In addition, it is the only quark whose Yukawa coupling to the Higgs boson is order of unity. For these reasons the top quark plays a special role in the Standard Model of Particle Physics and in many of its extensions. An accurate knowledge of its properties (mass, couplings, production cross section, decay branching ratios, etc.) can bring key information on fundamental interactions at the electroweak breaking scale and beyond. In this talk the latest measurements of the characteristics of the top quark carried out in the ATLAS experiment at the Large Hadron Collider are presented.
Baryon inhomogeneity from the cosmic quark-hadron phase transition
International Nuclear Information System (INIS)
Kurki-Suonio, H.
1991-01-01
We discuss the generation of inhomogeneity in the baryon-number density during the cosmic quark-hadron phase transition. We use a simple model with thin-wall phase boundaries and ideal-gas equations of state. The nucleation of the phase transition introduces a new distance scale into the universe which will be the scale of the generated inhomogeneity. We review the estimate of this scale. During the transition baryon number is likely to collect onto a layer at the phase boundary. These layers may in the end be deposited as small regions of very high baryon density. 21 refs., 1 fig
Kaon quark distribution functions in the chiral constituent quark model
Watanabe, Akira; Sawada, Takahiro; Kao, Chung Wen
2018-04-01
We investigate the valence u and s ¯ quark distribution functions of the K+ meson, vK (u )(x ,Q2) and vK (s ¯)(x ,Q2), in the framework of the chiral constituent quark model. We judiciously choose the bare distributions at the initial scale to generate the dressed distributions at the higher scale, considering the meson cloud effects and the QCD evolution, which agree with the phenomenologically satisfactory valence quark distribution of the pion and the experimental data of the ratio vK (u )(x ,Q2)/vπ (u )(x ,Q2) . We show how the meson cloud effects affect the bare distribution functions in detail. We find that a smaller S U (3 ) flavor symmetry breaking effect is observed, compared with results of the preceding studies based on other approaches.
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.
Domain wall QCD with physical quark masses
Blum, T.; Christ, N.H.; Frison, J.; Garron, N.; Hudspith, R.J.; Izubuchi, T.; Janowski, T.; Jung, C.; Jüttner, A.; Kelly, C.; Kenway, R.D.; Lehner, C.; Marinkovic, M.; Mawhinney, R.D.; McGlynn, G.; Murphy, D.J.; Ohta, S.; Portelli, A.; Sachrajda, C.T.; Soni, A.
2016-01-01
We present results for several light hadronic quantities ($f_\\pi$, $f_K$, $B_K$, $m_{ud}$, $m_s$, $t_0^{1/2}$, $w_0$) obtained from simulations of 2+1 flavor domain wall lattice QCD with large physical volumes and nearly-physical pion masses at two lattice spacings. We perform a short, O(3)%, extrapolation in pion mass to the physical values by combining our new data in a simultaneous chiral/continuum `global fit' with a number of other ensembles with heavier pion masses. We use the physical values of $m_\\pi$, $m_K$ and $m_\\Omega$ to determine the two quark masses and the scale - all other quantities are outputs from our simulations. We obtain results with sub-percent statistical errors and negligible chiral and finite-volume systematics for these light hadronic quantities, including: $f_\\pi$ = 130.2(9) MeV; $f_K$ = 155.5(8) MeV; the average up/down quark mass and strange quark mass in the $\\bar {\\rm MS}$ scheme at 3 GeV, 2.997(49) and 81.64(1.17) MeV respectively; and the neutral kaon mixing parameter, $B_K$...
Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija
Flavour inclusive, udsc and b fragmentation functions in unbiased jets, and flavour inclusive, udsc, b and gluon fragmentation functions in biased jets are measured in e+e- annihilations from data collected at centre-of-mass energies of 91.2, and 183-209 GeV with the OPAL detector at LEP. The unbiased jets are defined by hemispheres of inclusive hadronic events, while the biased jet measurements are based on three-jet events selected with jet algorithms. Several methods are employed to extract the fragmentation functions over a wide range of scales. Possible biases are studied in the results are obtained. The fragmentation functions are compared to results from lower energy e+e- experiments and with earlier LEP measurements and are found to be consistent. Scaling violations are observed and are found to be stronger for the fragmentation functions of gluon jets than for those of quarks. The measured fragmentation functions are compared to three recent theoretical next-to-leading order calculations and to the p...
Energy Technology Data Exchange (ETDEWEB)
Kanki, T [Osaka Univ., Toyonaka (Japan). Coll. of General Education
1976-12-01
We present a quark-gluon-parton model in which quark-partons and gluons make clusters corresponding to two or three constituent quarks (or anti-quarks) in the meson or in the baryon, respectively. We explicitly construct the constituent quark state (cluster), by employing the Kuti-Weisskopf theory and by requiring the scaling. The quark additivity of the hadronic total cross sections and the quark counting rules on the threshold powers of various distributions are satisfied. For small x (Feynman fraction), it is shown that the constituent quarks and quark-partons have quite different probability distributions. We apply our model to hadron-hadron inclusive reactions, and clarify that the fragmentation and the diffractive processes relate to the constituent quark distributions, while the processes in or near the central region are controlled by the quark-partons. Our model gives the reasonable interpretation for the experimental data and much improves the usual ''constituent interchange model'' result near and in the central region (x asymptotically equals x sub(T) asymptotically equals 0).
International Nuclear Information System (INIS)
Granier de Cassagnac, R.
2010-01-01
The quark-gluon plasma (QGP) is a state of matter in which the universe was expected to be a few micro-seconds after the big-bang. Violent collisions of heavy ions are supposed to re-create this state in particle accelerators. Numerous signatures of this fugacious state have already been observed at the RHIC (relativistic heavy ion collider). The first evidence of the violence of collisions is the number of generated particles: about 6000 per collision, mostly hadrons. This figure seems high but in fact is less than theoretically expected and is the first sign of the formation of a QGP that saturates the density of gluons. Another sign, observed at the RHIC is the damping of the particle jets that are produced in the collision. This damping is consistent with the crossing of a medium whose density is so high that it can not be made of hadrons but of partons. In the RHIC experiments the collective behaviour of quarks and gluons shows that they are strongly interacting with one another. This fact supports the idea that the QGP is more a perfect liquid rather than an ideal gas in which quarks and gluons move freely. (A.C.)
Instanton vacuum at finite density of quark matter
International Nuclear Information System (INIS)
Molodtsov, S.V.; Zinovjev, G.M.
2002-01-01
We study light quark interactions in the instanton liquid at finite quark/baryon number density analyzing chiral and diquark condensates and investigate the behaviors of quark dynamical mass and both condensates together with instanton liquid density as a function of quark chemical potential. We conclude the quark impact (estimated in the tadpole approximation) on the instanton liquid could shift color superconducting phase transition to higher values of the chemical potential bringing critical quark matter density to the values essentially higher than conventional nuclear one
Scaling up adsorption media reactors for copper removal with the aid of dimensionless numbers.
Chang, Ni-Bin; Houmann, Cameron; Wanielista, Martin
2016-02-01
Adsorption media may be used to sorb copper in an aquatic environment for pollution control. Effective design of adsorption media reactors is highly dependent on selection of the hydraulic residence time when scaling up a pilot-scale reactor to a field-scale reactor. This paper seeks to improve scaling-up technique of the reactor design process through the use of the Damköhler and Péclet numbers via a dimensional analysis. A new scaling-up theory is developed in this study through a joint consideration of the Damköhler and Péclet numbers for a constant media particle size such that a balance between transport control and reaction control can be harmonized. A series of column breakthrough tests at varying hydraulic residence times revealed a clear peak adsorption capacity at a Damköhler number of 2.74. The Péclet numbers for the column breakthrough tests indicated that mechanical dispersion is an important effect that requires further consideration in the scaling-up process. However, perfect similitude of the Damköhler number cannot be maintained for a constant media particle size, and relaxation of hydrodynamic similitude through variation of the Péclet number must occur. Copyright © 2015 Elsevier Ltd. All rights reserved.
Medicine in words and numbers: a cross-sectional survey comparing probability assessment scales
Directory of Open Access Journals (Sweden)
Koele Pieter
2007-06-01
Full Text Available Abstract Background In the complex domain of medical decision making, reasoning under uncertainty can benefit from supporting tools. Automated decision support tools often build upon mathematical models, such as Bayesian networks. These networks require probabilities which often have to be assessed by experts in the domain of application. Probability response scales can be used to support the assessment process. We compare assessments obtained with different types of response scale. Methods General practitioners (GPs gave assessments on and preferences for three different probability response scales: a numerical scale, a scale with only verbal labels, and a combined verbal-numerical scale we had designed ourselves. Standard analyses of variance were performed. Results No differences in assessments over the three response scales were found. Preferences for type of scale differed: the less experienced GPs preferred the verbal scale, the most experienced preferred the numerical scale, with the groups in between having a preference for the combined verbal-numerical scale. Conclusion We conclude that all three response scales are equally suitable for supporting probability assessment. The combined verbal-numerical scale is a good choice for aiding the process, since it offers numerical labels to those who prefer numbers and verbal labels to those who prefer words, and accommodates both more and less experienced professionals.
Quark mean field theory and consistency with nuclear matter
International Nuclear Information System (INIS)
Dey, J.; Tomio, L.; Dey, M.; Frederico, T.
1989-01-01
1/N c expansion in QCD (with N c the number of colours) suggests using a potential from meson sector (e.g. Richardson) for baryons. For light quarks a σ field has to be introduced to ensure chiral symmetry breaking ( χ SB). It is found that nuclear matter properties can be used to pin down the χ SB-modelling. All masses, M Ν , m σ , m ω are found to scale with density. The equations are solved self consistently. (author)
Who needs more than four quarks
International Nuclear Information System (INIS)
Montonen, C.; Roos, M.
1976-09-01
The authors argue that there are no compelling reasons, experimental or theoretical, for an enlarged quark sector. They show that there is a large number of acceptable anomaly-free models with the usual four-quark-sector and one or two heavy charged leptons. (L.M.K.)
International Nuclear Information System (INIS)
Huang Yimin; Bhattacharjee, A.
2010-01-01
The Sweet-Parker layer in a system that exceeds a critical value of the Lundquist number (S) is unstable to the plasmoid instability. In this paper, a numerical scaling study has been done with an island coalescing system driven by a low level of random noise. In the early stage, a primary Sweet-Parker layer forms between the two coalescing islands. The primary Sweet-Parker layer breaks into multiple plasmoids and even thinner current sheets through multiple levels of cascading if the Lundquist number is greater than a critical value S c ≅4x10 4 . As a result of the plasmoid instability, the system realizes a fast nonlinear reconnection rate that is nearly independent of S, and is only weakly dependent on the level of noise. The number of plasmoids in the linear regime is found to scales as S 3/8 , as predicted by an earlier asymptotic analysis [N. F. Loureiro et al., Phys. Plasmas 14, 100703 (2007)]. In the nonlinear regime, the number of plasmoids follows a steeper scaling, and is proportional to S. The thickness and length of current sheets are found to scale as S -1 , and the local current densities of current sheets scale as S -1 . Heuristic arguments are given in support of theses scaling relations.
Quark confinement in a constituent quark model
International Nuclear Information System (INIS)
Langfeld, K.; Rho, M.
1995-01-01
On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation function. We then propose a confining Nambu-Jona-Lasinio-type model. The confinement is implemented in analogy to Anderson localization in condensed matter systems. We study the model's phase structure as well as its behavior under extreme conditions, i.e. high temperature and/or high density
Quark exchange and nuclear dynamics
International Nuclear Information System (INIS)
Moniz, E.J.
1985-01-01
This paper gives a qualitative understanding of hadronic phenomena in terms of quark degrees of freedom. The basic model which incorporates saturating confining interactions and the study of hadron-hadron scattering has been carried through in collaboration with F. Lenz, J.T. Londergan, R. Rosenfelder, M. Stingl and K. Yazaki. It is shown that minimal confining dynamics together with exchange symmetry indeed leads to a remarkable range of phenomena at both the nuclear and particle energy scales. Most observables are well described by an effective hadron theory, the quark momentum distribution being the major exception. These features emerge even in the simplest model, namely, U(1) color and hadrons composed of two quarks (anti qq or qq). The author concentrates here on this model. In the concluding section, he remarks on the SU(N) results, particularly on the extent to which the color-hidden dynamics are constrained by examining the systematics of nuclear and hadronic phenomena. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Nejad, S.M.M. [Yazd University, Faculty of Physics, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O.Box 19395-5531, Tehran (Iran, Islamic Republic of); Balali, Mahboobe [Yazd University, Faculty of Physics, P.O. Box 89195-741, Yazd (Iran, Islamic Republic of)
2016-03-15
We present the analytical expressions for the next-to-leading order corrections to the partial decay width t(↑) → bW{sup +}, followed by b @→ H{sub b}X, for nonzero b-quark mass (m{sub b} ≠ 0) in the fixed-flavor-number scheme (FFNs). To make the predictions for the energy distribution of outgoing hadrons H{sub b}, as a function of the normalized H{sub b}-energy fraction x{sub H}, we apply the general-mass variable-flavor-number scheme (GM-VFNs) in a specific helicity coordinate system where the polarization of top quark is evaluated relative to the b-quark momentum. We also study the effects of gluon fragmentation and finite hadron mass on the hadron energy spectrum so that hadron masses are responsible for the low x{sub H} threshold. In order to describe both the b-quark and the gluon hadronizations in top decays we apply realistic and nonperturbative fragmentation functions extracted through a global fit to the e{sup +}e{sup -} annihilation data from CERN LEP1 and SLAC SLC by relying on their universality and scaling violations. (orig.)
Introduction: Scaling and structure in high Reynolds number wall-bounded flows
International Nuclear Information System (INIS)
McKeon, B.J.; Sreenivasan, K.R.
2007-05-01
The papers discussed in this report are dealing with the following aspects: Fundamental scaling relations for canonical flows and asymptotic approach to infinite Reynolds numbers; large and very large scales in near-wall turbulences; the influence of roughness and finite Reynolds number effects; comparison between internal and external flows and the universality of the near-wall region; qualitative and quantitative models of the turbulent boundary layer; the neutrally stable atmospheric surface layer as a model for a canonical zero-pressure-gradient boundary layer (author)
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.
Compositeness of quarks and leptons
International Nuclear Information System (INIS)
Peskin, M.E.
1981-01-01
I review along grand lines the theoretical ideas associated with the notion that quarks and leptons are composite. I first discuss various constituent pictures which have been proposed to account for the quantum numbers of the observed quarks and leptons, a study I call the Quantum Numerology. I then discuss some new theoretical developments of the past two years which bear on the subject of composite fermions and which make plausible (or rule out) some of the major dynamical assumptions of these constituent models. Finally, I discuss the consequences of the compositeness of quarks and leptons by setting up a series of scenarios for this compositeness and exploring, for each scenario, its experimental implications. (orig./HSI)
Experimental scaling of fluctuations and confinement with Lundquist number in the RFP
International Nuclear Information System (INIS)
Stoneking, M.R.; Chapman, J.T.; Prager, S.C.; Sarff, J.S.
1997-09-01
The scaling of the magnetic and velocity fluctuations with Lundquist number (S) is examined experimentally over a range of values from 7 x 10 4 to 10 6 in a reversed field pinch (RFP) plasma. Magnetic fluctuations do not scale uniquely with the Lundquist number. At high (relative) density, fluctuations scale as b∝S -0.18 , and fluctuations are almost independent of S at low relative density, b∝S -0.07 ; however both exponents fall in the range of theoretical and numerical predictions. At high relative density, the scaling of the energy confinement time follows expectations for transport in a stochastic magnetic field. A confinement scaling law (nτ E ∝β 4/5 T -7/10 A -3/5 I φ 2 ) is derived assuming the persistent dominance of stochastic magnetic diffusion in the RFP and on the measured scaling of magnetic fluctuations. The peak velocity fluctuations during a sawtooth cycle scale marginally stronger than magnetic fluctuations but weaker than a simple Ohm's law prediction. The sawtooth period is determined by a resistive-Alfvenic hybrid time (T saw ∝√(τ R τ Alf )) rather than a purely resistive time
Symmetries and aggregates of quarks as constituents of hadrons
International Nuclear Information System (INIS)
Kibler, M.
1982-07-01
The interest of the Lie algebra of the group SU(n) for the classification of hadrons and the description of some of their static properties is emphasized for n=3, 4, 6, 8. The cases n=3 and 4 allow to introduce the quark flavors (u,d,s,) and (u,d,c,s), respectively, and the consideration of the spin of hadrons leads to the chain SU(2m) contains SU(m) x SU(2). The hadrons are described as bound states or aggregates of quarks of type quark-quark-quark for baryons and quark-antiquark for mesons. The Pauli exclusion principle applied to the three-quark baryons requires the introduction of a new quantum number, the color: each flavor of quark then comes in three colors
Is the number and size of scales in Liolaemus lizards driven by climate?
José Tulli, María; Cruz, Félix B
2018-05-03
Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they occur. To buffer these fluctuations, ectotherms use different strategies, including the integument, which is a barrier that minimizes temperature exchange between the inner body and the surrounding air. In lizards, this barrier is constituted by keratinized scales of variable size, shape and texture, and its main function is protection, water loss avoidance and thermoregulation. The size of scales in lizards has been proposed to vary in relation to climatic gradients; however, it has also been observed that in some groups of Iguanian lizards could be related to phylogeny. Thus, here, we studied the area and number of scales (dorsal and ventral) of 61 species of Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the nature of the variation of the scales with climate, and found that the number and size of scales are related to climatic variables, such as temperature and geographical variables as altitude. The evolutionary process that better explained how these morphological variables evolved was the Ornstein-Uhlenbeck model. The number of scales seemed to be related to common ancestry, whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological traits. In fact, the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind and is thus under less pressure to change in response to alterations in external conditions. It is possible that scale ornamentation such as keels and granulosity may bring some more information in this regard. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
International Nuclear Information System (INIS)
Bjorken, J.D.
1985-12-01
Even if stable hadrons with fractional charge do not exist, most of the criteria of observability used for ordinary elementary particles apply in principle to quarks as well. This is especially true in a simplified world containing only hadrons made of top quarks and gluons. In the real world containing light quarks, essential complications do occur, but most of the conclusions survive
International Nuclear Information System (INIS)
Jacob, Maurice
1988-01-01
The 'Quark Matter' Conference caters for physicists studying nuclear matter under extreme conditions. The hope is that relativistic (high energy) heavy ion collisions allow formation of the long-awaited quark-gluon plasma, where the inter-quark 'colour' force is no longer confined inside nucleon-like dimensions
Phase structure of lattice QCD for general number of flavors
International Nuclear Information System (INIS)
Iwasaki, Y.; Kanaya, K.; Yoshie, T.; Kaya, S.; Sakai, S.
2004-01-01
We investigate the phase structure of lattice QCD for the general number of flavors in the parameter space of gauge coupling constant and quark mass, employing the one-plaquette gauge action and the standard Wilson quark action. Performing a series of simulations for the number of flavors N F =6-360 with degenerate-mass quarks, we find that when N F ≥7 there is a line of a bulk first order phase transition between the confined phase and a deconfined phase at a finite current quark mass in the strong coupling region and the intermediate coupling region. The massless quark line exists only in the deconfined phase. Based on these numerical results in the strong coupling limit and in the intermediate coupling region, we propose the following phase structure, depending on the number of flavors whose masses are less than Λ d which is the physical scale characterizing the phase transition in the weak coupling region: When N F ≥17, there is only a trivial IR fixed point and therefore the theory in the continuum limit is free. On the other hand, when 16≥N F ≥7, there is a nontrivial IR fixed point and therefore the theory is nontrivial with anomalous dimensions, however, without quark confinement. Theories which satisfy both quark confinement and spontaneous chiral symmetry breaking in the continuum limit exist only for N F ≤6
Weighing and Body Monitoring among College Women: The Scale Number as an Emotional Barometer
Mintz, Laurie B.; Awad, Germine H.; Stinson, Rebecca D.; Bledman, Rashanta A.; Coker, Angela D.; Kashubeck-West, Susan; Connelly, Kathleen
2013-01-01
This study investigated weighing and body-monitoring behaviors, as well as psychological and behavioral reactions to weighing, among female college students. Weighing and body monitoring were engaged in by the majority of participants. Participants changed food intake and exercise based on weight. About 63% reported that the scale number impacts…
Andrew P. Kinziger; Rodney J. Nakamoto; Bret C. Harvey
2014-01-01
Given the general pattern of invasions with severe ecological consequences commonly resulting from multiple introductions of large numbers of individuals on the intercontinental scale, we explored an example of a highly successful, ecologically significant invader introduced over a short distance, possibly via minimal propagule pressure. The Sacramento pikeminnow (
Quark Matter May Not Be Strange.
Holdom, Bob; Ren, Jing; Zhang, Chen
2018-06-01
If quark matter is energetically favored over nuclear matter at zero temperature and pressure, then it has long been expected to take the form of strange quark matter (SQM), with comparable amounts of u, d, and s quarks. The possibility of quark matter with only u and d quarks (udQM) is usually dismissed because of the observed stability of ordinary nuclei. However, we find that udQM generally has lower bulk energy per baryon than normal nuclei and SQM. This emerges in a phenomenological model that describes the spectra of the lightest pseudoscalar and scalar meson nonets. Taking into account the finite size effects, udQM can be the ground state of baryonic matter only for baryon number A>A_{min} with A_{min}≳300. This ensures the stability of ordinary nuclei and points to a new form of stable matter just beyond the periodic table.
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
Perturbative current quark masses in QCD
International Nuclear Information System (INIS)
Scadron, M.D.
1982-01-01
Neutral PCAC current quark masses follow from the covariant light plane of QCD requirement that α-m-circumflex(M), which is not inconsistent with the spontaneous breakdown of chiral symmetry. The resulting current quark mass ratio (m sub(s)/m-circumflex) sub(curr)=5 and scale m-circumflex sub(curr)=62 MeV at M=2 Gev are compatible with the observed πNσ - term, the Goldberger-Treiman discrepancy, the low-lying 0 - , 1/2 + , 1 - , 3/2 + hadron mass spectrum, the flavor independence of the dynamically generated quark mass and the perturbative weak binding limit. (author)
Space-Time Geometry of Quark and Strange Quark Matter
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We study quark and strange quark matter in the context of general relativity. For this purpose, we solve Einstein's field equations for quark and strange quark matter in spherical symmetric space-times. We analyze strange quark matter for the different equations of state (EOS) in the spherical symmetric space-times, thus we are able to obtain the space-time geometries of quark and strange quark matter. Also, we discuss die features of the obtained solutions. The obtained solutions are consistent with the results of Brookhaven Laboratory, i.e. the quark-gluon plasma has a vanishing shear (i.e. quark-gluon plasma is perfect).
Jan-e~Alam; Subhasis~Chattopadhyay; Tapan~Nayak
2008-10-01
Quark Matter 2008—the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions was held in Jaipur, the Pink City of India, from 4-10 February, 2008. Organizing Quark Matter 2008 in India itself indicates the international recognition of the Indian contribution to the field of heavy-ion physics, which was initiated and nurtured by Bikash Sinha, Chair of the conference. The conference was inaugurated by the Honourable Chief Minister of Rajasthan, Smt. Vasundhara Raje followed by the key note address by Professor Carlo Rubbia. The scientific programme started with the theoretical overview, `SPS to RHIC and onwards to LHC' by Larry McLerran followed by several theoretical and experimental overview talks on the ongoing experiments at SPS and RHIC. The future experiments at the LHC, FAIR and J-PARC, along with the theoretical predictions, were discussed in great depth. Lattice QCD predictions on the nature of the phase transition and critical point were vigorously debated during several plenary and parallel session presentations. The conference was enriched by the presence of an unprecedented number of participants; about 600 participants representing 31 countries across the globe. This issue contains papers based on plenary talks and oral presentations presented at the conference. Besides invited and contributed talks, there were also a large number of poster presentations. Members of the International Advisory Committee played a pivotal role in the selection of speakers, both for plenary and parallel session talks. The contributions of the Organizing Committee in all aspects, from helping to prepare the academic programme down to arranging local hospitality, were much appreciated. We thank the members of both the committees for making Quark Matter 2008 a very effective and interesting platform for scientific deliberations. Quark Matter 2008 was financially supported by: Air Liquide (New Delhi) Board of Research Nuclear Sciences (Mumbai) Bose
Nondimensional scaling of magnetorheological rotary shear mode devices using the Mason number
Becnel, Andrew C.; Sherman, Stephen; Hu, Wei; Wereley, Norman M.
2015-04-01
Magnetorheological fluids (MRFs) exhibit rapidly adjustable viscosity in the presence of a magnetic field, and are increasingly used in adaptive shock absorbers for high speed impacts, corresponding to high fluid shear rates. However, the MRF properties are typically measured at very low (γ ˙10,000 s-1) Searle cell magnetorheometer, along with a full scale rotary-vane magnetorheological energy absorber (γ ˙>25,000 s-1) are employed to analyze MRF property scaling across shear rates using a nondimensional Mason number to generate an MRF master curve. Incorporating a Reynolds temperature correction factor, data from both experiments is shown to collapse to a single master curve, supporting the use of Mason number to correlate low- and high-shear rate characterization data.
Quark fragmentation into 3PJ quarkonium
International Nuclear Information System (INIS)
Ma, J.P.
1996-01-01
The functions of parton fragmentation into 3 P J quarkonium at order α 2 s are calculated, where the parton can be a heavy or a light quark. The obtained functions explicitly satisfy the Altarelli-Parisi equation and they are divergent, behaving as z -1 near z = O. However, if one choses the renormalization scale as twice of the heavy quark mass, the fragmentation functions are regular over the whole range of z. 15 refs., 2 figs
International Nuclear Information System (INIS)
Stehlik, M.; Ososkov, G.A.
2003-01-01
The statistical problem to expand the experimental distribution of transverse momenta into Rayleigh distribution is considered. A high-efficient testing procedure for testing the hypothesis of the homogeneity of the observed measurements which is optimal in the sense of Bahadur is constructed. The exact likelihood ratio (LR) test of the scale parameter of the Rayleigh distribution is proposed for cases when the hypothesis of homogeneity holds. Otherwise the efficient procedure for testing the number of components in the mixture is also proposed
Chaudhuri, Swetaprovo; Wu, Fujia; Law, Chung
2012-11-01
In this work we clarify the role of Markstein diffusivity on turbulent flame speed and it's scaling, from analysis and experimental measurements on constant-pressure expanding flames propagating in near isotropic turbulence. For all C0-C4 hydrocarbon-air mixtures presented in this work and recently published C8 data from Leeds, the normalized turbulent flame speed data of individual mixtures approximately follows the recent theoretical and experimental ReT, f 0 . 5 scaling, where the average radius is the length scale and thermal diffusivity is the transport property. We observe that for a constant ReT, f 0 . 5 , the normalized turbulent flame speed decreases with increasing Mk. This could be explained by considering Markstein diffusivity as the large wavenumber, flame surface fluctuation dissipation mechanism. As originally suggested by the theory, replacing thermal diffusivity with Markstein diffusivity in the turbulence Reynolds number definition above, the present and Leeds dataset could be scaled by the new ReT, f 0 . 5 irrespective of the fuel considered, equivalence ratio, pressure and turbulence intensity for positive Mk flames. This work was supported by the Combustion Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Basic Energy Sciences under Award Number DE-SC0001198 and by the Air Force Office of Scientific Research.
Turbulence Enhancement by Fractal Square Grids: Effects of the Number of Fractal Scales
Omilion, Alexis; Ibrahim, Mounir; Zhang, Wei
2017-11-01
Fractal square grids offer a unique solution for passive flow control as they can produce wakes with a distinct turbulence intensity peak and a prolonged turbulence decay region at the expense of only minimal pressure drop. While previous studies have solidified this characteristic of fractal square grids, how the number of scales (or fractal iterations N) affect turbulence production and decay of the induced wake is still not well understood. The focus of this research is to determine the relationship between the fractal iteration N and the turbulence produced in the wake flow using well-controlled water-tunnel experiments. Particle Image Velocimetry (PIV) is used to measure the instantaneous velocity fields downstream of four different fractal grids with increasing number of scales (N = 1, 2, 3, and 4) and a conventional single-scale grid. By comparing the turbulent scales and statistics of the wake, we are able to determine how each iteration affects the peak turbulence intensity and the production/decay of turbulence from the grid. In light of the ability of these fractal grids to increase turbulence intensity with low pressure drop, this work can potentially benefit a wide variety of applications where energy efficient mixing or convective heat transfer is a key process.
International Nuclear Information System (INIS)
Hill, C.T.
1981-10-01
Exactly two years ago at the 1979 Lepton, Photon Symposium at Fermilab, Mary K. Gaillard presented a histogram showing the number of papers predicting a given value of toponium mass as a function of mass. I have translated this into the t-quark mass and presented it including several other bounds arising from an assortment of physical principles and arguments. These include Veltman's rho-parameter bound, a well-known bound from grand unification due to Cabibbo, Maiani, Parisi and Petronzio, and considerations of Higgs potential stability and unitarity. The central popular mechanism for generating t-quark mass predictions, you will recall, was to employ discrete symmetries in the Higgs sector of left-right symmetric models, leading to a central popular prediction of m approx. 15 GeV. It should be noted that discrete symmetries can lead to larger values (and smaller ones), but clearly with diminished unanimity. We should also mention independent ideas which presume a basic universal ratio of m/sup (+2/3)//m/sup (-1/3)/ for all generations and lead to a prediction of m approx. 26 GeV. In the intervening two years physicists have kept busy generating new t-quark mass predictions and Petra has pushed the lower bound up to approx. 18.5 GeV. New physical ideas have emerged which now focus more directly upon dynamical aspects of grand-unification. uv versus ir behavior of field theory, and nonlinear renormalization group equations with quasi-fixed point behavior. Some of these ideas make statements about hypothetical fourth generation fermion masses. These ideas are reviewed with an eye to statements one can make about mass scales beyond the third generation, as well
On the ultimate uncertainty of the top quark pole mass
Energy Technology Data Exchange (ETDEWEB)
Beneke, M. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Marquard, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Nason, P. [INFN, Sezione di Milano Bicocca (Italy); Steinhauser, M. [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik
2016-05-15
We combine the known asymptotic behaviour of the QCD perturbation series expansion, which relates the pole mass of a heavy quark to the MS mass, with the exact series coefficients up to the four-loop order to determine the ultimate uncertainty of the top-quark pole mass due to the renormalon divergence. We perform extensive tests of our procedure by varying the number of colours and flavours, as well as the scale of the strong coupling and the MS mass, and conclude that this uncertainty is around 70 MeV. We further estimate the additional contribution to the mass relation from the five-loop correction and beyond to be 250 MeV.
On the ultimate uncertainty of the top quark pole mass
International Nuclear Information System (INIS)
Beneke, M.; Nason, P.; Steinhauser, M.
2016-05-01
We combine the known asymptotic behaviour of the QCD perturbation series expansion, which relates the pole mass of a heavy quark to the MS mass, with the exact series coefficients up to the four-loop order to determine the ultimate uncertainty of the top-quark pole mass due to the renormalon divergence. We perform extensive tests of our procedure by varying the number of colours and flavours, as well as the scale of the strong coupling and the MS mass, and conclude that this uncertainty is around 70 MeV. We further estimate the additional contribution to the mass relation from the five-loop correction and beyond to be 250 MeV.
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
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.
Required number of records for ASCE/SEI 7 ground-motion scaling procedure
Reyes, Juan C.; Kalkan, Erol
2011-01-01
The procedures and criteria in 2006 IBC (International Council of Building Officials, 2006) and 2007 CBC (International Council of Building Officials, 2007) for the selection and scaling ground-motions for use in nonlinear response history analysis (RHA) of structures are based on ASCE/SEI 7 provisions (ASCE, 2005, 2010). According to ASCE/SEI 7, earthquake records should be selected from events of magnitudes, fault distance, and source mechanisms that comply with the maximum considered earthquake, and then scaled so that the average value of the 5-percent-damped response spectra for the set of scaled records is not less than the design response spectrum over the period range from 0.2Tn to 1.5Tn sec (where Tn is the fundamental vibration period of the structure). If at least seven ground-motions are analyzed, the design values of engineering demand parameters (EDPs) are taken as the average of the EDPs determined from the analyses. If fewer than seven ground-motions are analyzed, the design values of EDPs are taken as the maximum values of the EDPs. ASCE/SEI 7 requires a minimum of three ground-motions. These limits on the number of records in the ASCE/SEI 7 procedure are based on engineering experience, rather than on a comprehensive evaluation. This study statistically examines the required number of records for the ASCE/SEI 7 procedure, such that the scaled records provide accurate, efficient, and consistent estimates of" true" structural responses. Based on elastic-perfectly-plastic and bilinear single-degree-of-freedom systems, the ASCE/SEI 7 scaling procedure is applied to 480 sets of ground-motions. The number of records in these sets varies from three to ten. The records in each set were selected either (i) randomly, (ii) considering their spectral shapes, or (iii) considering their spectral shapes and design spectral-acceleration value, A(Tn). As compared to benchmark (that is, "true") responses from unscaled records using a larger catalog of ground
The Stokes number approach to support scale-up and technology transfer of a mixing process.
Willemsz, Tofan A; Hooijmaijers, Ricardo; Rubingh, Carina M; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees
2012-09-01
Transferring processes between different scales and types of mixers is a common operation in industry. Challenges within this operation include the existence of considerable differences in blending conditions between mixer scales and types. Obtaining the correct blending conditions is crucial for the ability to break up agglomerates in order to achieve the desired blend uniformity. Agglomerate break up is often an abrasion process. In this study, the abrasion rate potential of agglomerates is described by the Stokes abrasion (St(Abr)) number of the system. The St(Abr) number equals the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. In this study, the St(Abr) approach demonstrates to be a useful tool to predict the abrasion of agglomerates during blending when technology is transferred between mixer scales/types. Applying the St(Abr) approach revealed a transition point between parameters that determined agglomerate abrasion. This study gave evidence that (1) below this transition point, agglomerate abrasion is determined by a combination of impeller effects and by the kinetic energy density of the powder blend, whereas (2) above this transition point, agglomerate abrasion is mainly determined by the kinetic energy density of the powder blend.
Bulk viscosity in 2SC quark matter
International Nuclear Information System (INIS)
Alford, Mark G; Schmitt, Andreas
2007-01-01
The bulk viscosity of three-flavour colour-superconducting quark matter originating from the nonleptonic process u + s ↔ u + d is computed. It is assumed that up and down quarks form Cooper pairs while the strange quark remains unpaired (2SC phase). A general derivation of the rate of strangeness production is presented, involving contributions from a multitude of different subprocesses, including subprocesses that involve different numbers of gapped quarks as well as creation and annihilation of particles in the condensate. The rate is then used to compute the bulk viscosity as a function of the temperature, for an external oscillation frequency typical of a compact star r-mode. We find that, for temperatures far below the critical temperature T c for 2SC pairing, the bulk viscosity of colour-superconducting quark matter is suppressed relative to that of unpaired quark matter, but for T ∼> T c /30 the colour-superconducting quark matter has a higher bulk viscosity. This is potentially relevant for the suppression of r-mode instabilities early in the life of a compact star
Quark diquark symmetry breaking
International Nuclear Information System (INIS)
Souza, M.M. de
1980-01-01
Assuming the baryons are made of quark-diquark pairs, the wave functions for the 126 allowed ground states are written. The quark creation and annihilations operators are generalized to describe the quark-diquark structure in terms of a parameter σ. Assuming that all quark-quark interactions are mediated by gluons transforming like an octet of vector mesons, the effective Hamiltonian and the baryon masses as constraint equations for the elements of the mass matrix is written. The symmetry is the SU(6) sub(quark)x SU(21) sub(diquark) broken by quark-quark interactions respectively invariant under U(6), U(2) sub(spin), U(3) and also interactions transforming like the eighth and the third components of SU(3). In the limit of no quark-diquark structure (σ = 0), the ground state masses is titted to within 1% of the experimental data, except for the Δ(1232), where the error is almost 2%. Expanding the decuplet mass equations in terms of σ and keeping terms only up to the second order, this error is reduced to 67%. (Author) [pt
International Nuclear Information System (INIS)
Zurek, W H
2013-01-01
I show that random distributions of vortex–antivortex pairs (rather than of individual vortices) lead to scaling of typical winding numbers W trapped inside a loop of circumference C with the square root of that circumference, W∼√C, when the expected winding numbers are large, |W| ≫ 1. Such scaling is consistent with the Kibble–Zurek mechanism (KZM), with 〈W 2 〉 inversely proportional to ξ-hat , the typical size of the domain that can break symmetry in unison. (The dependence of ξ-hat on quench rate is predicted by KZM from critical exponents of the phase transition.) Thus, according to KZM, the dispersion √ 2 > scales as √(C/ ξ-hat ) for large W. By contrast, a distribution of individual vortices with randomly assigned topological charges would result in the dispersion scaling with the square root of the area inside C (i.e., √ 2 > ∼ C). Scaling of the dispersion of W as well as of the probability of detection of non-zero W with C and ξ-hat can be also studied for loops so small that non-zero windings are rare. In this case I show that dispersion varies not as 1/√( ξ-hat ), but as 1/ ξ-hat , which results in a doubling of the scaling of dispersion with the quench rate when compared to the large |W| regime. Moreover, the probability of trapping of non-zero W becomes approximately equal to 〈W 2 〉, and scales as 1/ ξ-hat 2 . This quadruples—as compared with √ 2 > ≃ √C/ξ-circumflex valid for large W—the exponent in the power law dependence of the frequency of trapping of |W| = 1 on ξ-hat when the probability of |W| > 1 is negligible. This change of the power law exponent by a factor of four—from 1/√( ξ-hat ) for the dispersion of large W to 1/ ξ-hat 2 for the frequency of non-zero W when |W| > 1 is negligibly rare—is of paramount importance for experimental tests of KZM. (paper)
The time scale for the transition to turbulence in a high Reynolds number, accelerated flow
International Nuclear Information System (INIS)
Robey, H.F.; Zhou Ye; Buckingham, A.C.; Keiter, P.; Remington, B.A.; Drake, R.P.
2003-01-01
An experiment is described in which an interface between materials of different density is subjected to an acceleration history consisting of a strong shock followed by a period of deceleration. The resulting flow at this interface, initiated by the deposition of strong laser radiation into the initially well characterized solid materials, is unstable to both the Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities. These experiments are of importance in their ability to access a difficult experimental regime characterized by very high energy density (high temperature and pressure) as well as large Reynolds number and Mach number. Such conditions are of interest, for example, in the study of the RM/RT induced mixing that occurs during the explosion of a core-collapse supernova. Under these experimental conditions, the flow is in the plasma state and given enough time will transition to turbulence. By analysis of the experimental data and a corresponding one-dimensional numerical simulation of the experiment, it is shown that the Reynolds number is sufficiently large (Re>10 5 ) to support a turbulent flow. An estimate of three key turbulence length scales (the Taylor and Kolmogorov microscales and a viscous diffusion scale), however, shows that the temporal duration of the present flow is insufficient to allow for the development of a turbulent inertial subrange. A methodology is described for estimating the time required under these conditions for the development of a fully turbulent flow
Quarks in hadrons and nuclei and electromagnetic probes
International Nuclear Information System (INIS)
Faessler, Amand
1995-01-01
Deuteron properties and nuclear magnetic moments are studied in the non-relativistic quark cluster model. The quark cluster model is modified to include chiral symmetry. This reduces the number of parameters. The σ meson is exchanged between quarks and not as in earlier versions between nucleons. The charge monopole, quadrupole and magnetic-dipole form factors and the tensor polarization of the deuteron in this microscopic meson-quark cluster model are calculated. The deuteron wave function is derived from a microscopic 6-quark Hamiltonian which, in addition to a quadratic confinement potential, includes the one-pion and the one-gluon exchange potentials between quarks. The electromagnetic current operators are constructed on the quark level, i.e., the photon is coupled directly to the quarks. Aside from the one-body impulse current, pionic and gluonic exchange current corrections are included. Due to the Pauli principle on the quark level, new quark interchange terms arise in the one-body and two-body current matrix elements, that are not present on the nucleon level. While these additional quark exchange currents are small for low momentum transfers, we find that they appreciably influence the electromagnetic structure of the deuteron beyond a momentum transfer of q = 5fm -1 . (author)
Parity doublers in chiral potential quark models
International Nuclear Information System (INIS)
Kalashnikova, Yu. S.; Nefediev, A. V.; Ribeiro, J. E. F. T.
2007-01-01
The effect of spontaneous breaking of chiral symmetry over the spectrum of highly excited hadrons is addressed in the framework of a microscopic chiral potential quark model (Generalised Nambu-Jona-Lasinio model) with a vectorial instantaneous quark kernel of a generic form. A heavy-light quark-antiquark bound system is considered, as an example, and the Lorentz nature of the effective light-quark potential is identified to be a pure Lorentz-scalar, for low-lying states in the spectrum, and to become a pure spatial Lorentz vector, for highly excited states. Consequently, the splitting between the partners in chiral doublets is demonstrated to decrease fast in the upper part of the spectrum so that neighboring states of an opposite parity become almost degenerate. A detailed microscopic picture of such a 'chiral symmetry restoration' in the spectrum of highly excited hadrons is drawn and the corresponding scale of restoration is estimated
Integrability in heavy quark effective theory
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.
Dakin, James T.
1974-01-01
Reviews theoretical principles underlying the quark model. Indicates that the agreement with experimental results and the understanding of the quark-quark force are two hurdles for the model to survive in the future. (CC)
Directory of Open Access Journals (Sweden)
Nitin Bhardwaj
2010-05-01
Full Text Available Through combinatorial regulation, regulators partner with each other to control common targets and this allows a small number of regulators to govern many targets. One interesting question is that given this combinatorial regulation, how does the number of regulators scale with the number of targets? Here, we address this question by building and analyzing co-regulation (co-transcription and co-phosphorylation networks that describe partnerships between regulators controlling common genes. We carry out analyses across five diverse species: Escherichia coli to human. These reveal many properties of partnership networks, such as the absence of a classical power-law degree distribution despite the existence of nodes with many partners. We also find that the number of co-regulatory partnerships follows an exponential saturation curve in relation to the number of targets. (For E. coli and Bacillus subtilis, only the beginning linear part of this curve is evident due to arrangement of genes into operons. To gain intuition into the saturation process, we relate the biological regulation to more commonplace social contexts where a small number of individuals can form an intricate web of connections on the internet. Indeed, we find that the size of partnership networks saturates even as the complexity of their output increases. We also present a variety of models to account for the saturation phenomenon. In particular, we develop a simple analytical model to show how new partnerships are acquired with an increasing number of target genes; with certain assumptions, it reproduces the observed saturation. Then, we build a more general simulation of network growth and find agreement with a wide range of real networks. Finally, we perform various down-sampling calculations on the observed data to illustrate the robustness of our conclusions.
Quark contact interactions at the LHC
Bazzocchi, F.; De Sanctis, U.; Fabbrichesi, M.; Tonero, A.
2012-06-01
Quark contact interactions are an important signal of new physics. We introduce a model in which the presence of a symmetry protects these new interactions from giving large corrections in flavor changing processes at low energies. This minimal model provides the basic set of operators which must be considered to contribute to the high-energy processes. To discuss their experimental signature in jet pairs produced in proton-proton collisions, we simplify the number of possible operators down to two. We show (for a representative integrated luminosity of 200pb-1 at s=7TeV) how the presence of two operators significantly modifies the bound on the characteristic energy scale of the contact interactions, which is obtained by keeping a single operator.
Quark flavour observables in the Littlest Higgs model with T-parity after LHC Run 1
Blanke, Monika; Recksiegel, Stefan
2016-04-02
The Littlest Higgs Model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. We present a new analysis of quark observables in the LHT model in view of the oncoming flavour precision era. We use all available information on the CKM parameters, lattice QCD input and experimental data on quark flavour observables and corresponding theoretical calculations, taking into account new lower bounds on the symmetry breaking scale and the mirror quark masses from the LHC. We investigate by how much the branching ratios for a number of rare $K$ and $B$ decays are still allowed to depart from their SM values. This includes $K^+\\to\\pi^+\
Report of the Quark Flavor Physics Working Group
Butler, J N; Ritchie, J L; Cirigliano, V; Kettell, S; Briere, R; Petrov, A A; Schwartz, A; Skwarnicki, T; Zupan, J; Christ, N; Sharpe, S R; Van de Water, R S; Altmannshofer, W; Arkani-Hamed, N; Artuso, M; Asner, D M; Bernard, C; Bevan, A J; Blanke, M; Bonvicini, G; Browder, T E; Bryman, D A; Campana, P; Cenci, R; Cline, D; Comfort, J; Cronin-Hennessy, D; Datta, A; Dobbs, S; Duraisamy, M; El-Khadra, A X; Fast, J E; Forty, R; Flood, K T; Gershon, T; Grossman, Y; Hamilton, B; Hill, C T; Hill, R J; Hitlin, D G; Jaffe, D E; Jawahery, A; Jessop, C P; Kagan, A L; Kaplan, D M; Kohl, M; Krizan, P; Kronfeld, A S; Lee, K; Littenberg, L S; MacFarlane, D B; Mackenzie, P B; Meadows, B T; Olsen, J; Papucci, M; Parsa, Z; Paz, G; Perez, G; Piilonen, L E; Pitts, K; Purohit, M V; Quinn, B; Ratcliff, B N; Roberts, D A; Rosner, J L; Rubin, P; Seeman, J; Seth, K K; Schmidt, B; Schopper, A; Sokoloff, M D; Soni, A; Stenson, K; Stone, S; Sundrum, R; Tschirhart, R; Vainshtein, A; Wah, Y W; Wilkinson, G; Wise, M B; Worcester, E; Xu, J; Yamanaka, T
2013-01-01
This report represents the response of the Intensity Frontier Quark Flavor Physics Working Group to the Snowmass charge. We summarize the current status of quark flavor physics and identify many exciting future opportunities for studying the properties of strange, charm, and bottom quarks. The ability of these studies to reveal the effects of new physics at high mass scales make them an essential ingredient in a well-balanced experimental particle physics program.
Theory of wire number scaling in wire-array Z pinches
International Nuclear Information System (INIS)
Desjarlais, M.P.; Marder, B.M.
1999-01-01
Pulsed-power-driven Z pinches, produced by imploding cylindrical arrays of many wires, have generated very high x-ray radiation powers (>200 TW) and energies (2 MJ). Experiments have revealed a steady improvement in Z-pinch performance with increasing wire number at fixed total mass and array radius. The dominant mechanism acting to limit the performance of these devices is believed to be the Rayleigh-Taylor instability which broadens the radially imploding plasma sheath and consequently reduces the peak radiation power. A model is presented which describes an amplification over the two-dimensional Rayleigh-Taylor growth rate brought about by kink-like forces on the individual wires. This amplification factor goes to zero as the number of wires approaches infinity. This model gives results which are in good agreement with the experimental data and provides a scaling for wire-array Z pinches. copyright 1999 American Institute of Physics
Mach number scaling of helicopter rotor blade/vortex interaction noise
Leighton, Kenneth P.; Harris, Wesley L.
1985-01-01
A parametric study of model helicopter rotor blade slap due to blade vortex interaction (BVI) was conducted in a 5 by 7.5-foot anechoic wind tunnel using model helicopter rotors with two, three, and four blades. The results were compared with a previously developed Mach number scaling theory. Three- and four-bladed rotor configurations were found to show very good agreement with the Mach number to the sixth power law for all conditions tested. A reduction of conditions for which BVI blade slap is detected was observed for three-bladed rotors when compared to the two-bladed baseline. The advance ratio boundaries of the four-bladed rotor exhibited an angular dependence not present for the two-bladed configuration. The upper limits for the advance ratio boundaries of the four-bladed rotors increased with increasing rotational speed.
The catamorphy of quark-lepton families
International Nuclear Information System (INIS)
Wilkinson, D.H.
1988-11-01
Quark-lepton families appear to be limited in number. This can be understood if they are catamorphically related. This is illustrated by a simple geometrical Ansatz that gives the correct number of fermion fields per family and limits the number of families to three
Scale-up of a Luminescent Solar Concentrator-Based Photomicroreactor via Numbering-up.
Zhao, Fang; Cambié, Dario; Janse, Jeroen; Wieland, Eric W; Kuijpers, Koen P L; Hessel, Volker; Debije, Michael G; Noël, Timothy
2018-01-02
The use of solar energy to power chemical reactions is a long-standing dream of the chemical community. Recently, visible-light-mediated photoredox catalysis has been recognized as the ideal catalytic transformation to convert solar energy into chemical bonds. However, scaling photochemical transformations has been extremely challenging due to Bouguer-Lambert-Beer law. Recently, we have pioneered the development of luminescent solar concentrator photomicroreactors (LSC-PMs), which display an excellent energy efficiency. These devices harvest solar energy, convert the broad solar energy spectrum to a narrow-wavelength region, and subsequently waveguide the re-emitted photons to the reaction channels. Herein, we report on the scalability of such LSC-PMs via a numbering-up strategy. Paramount in our work was the use of molds that were fabricated via 3D printing. This allowed us to rapidly produce many different prototypes and to optimize experimentally key design aspects in a time-efficient fashion. Reactors up to 32 parallel channels have been fabricated that display an excellent flow distribution using a bifurcated flow distributor (standard deviations below 10%). This excellent flow distribution was crucial to scale up a model reaction efficiently, displaying yields comparable to those obtained in a single-channel device. We also found that interchannel spacing is an important and unique design parameter for numbered-up LSC-PMs, which influences greatly the photon flux experienced within the reaction channels.
Quark ensembles with the infinite correlation length
Zinov'ev, G. M.; Molodtsov, S. V.
2015-01-01
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.
Quark ensembles with the infinite correlation length
International Nuclear Information System (INIS)
Zinov’ev, G. M.; Molodtsov, S. V.
2015-01-01
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble
Quark ensembles with the infinite correlation length
Energy Technology Data Exchange (ETDEWEB)
Zinov’ev, G. M. [National Academy of Sciences of Ukraine, Bogoliubov Institute for Theoretical Physics (Ukraine); Molodtsov, S. V., E-mail: molodtsov@itep.ru [Joint Institute for Nuclear Research (Russian Federation)
2015-01-15
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.
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.
International Nuclear Information System (INIS)
Frampton, P.H.; Jarlskog, C.
1985-01-01
It is shown that the quark mass matrices in the Standard Electroweak Model satisfy the empirical relation M = M 1 + Ψ(Λ 2 ), where M(M sp (')) refers to the mass matrix of the charge 2/3(-1/3) quarks normalized to the largest eigenvalue, m sub (t)(m sub (b)), and Λ = V sub (us) = 0.22
Colourless confinement for quarks
International Nuclear Information System (INIS)
Anon.
1994-01-01
The enigma of quarks is that they are there, hidden deep inside nucleons and other strongly interacting particles, but refuse to come out. The tighter the quark bonds are stretched, the more difficult they are to break. This dogma has been accepted for some thirty years but has never been mathematically proved
International Nuclear Information System (INIS)
Cartwright, Susan
1992-01-01
Like any other electrically charged particles, quarks should give out electromagnetic radiation (photons) when they vibrate. One of the physics results from CERN's LEP collider is the first clear observation of this quark radiation from electron-positron collisions. At lower energies this radiation could only be inferred
Energy Technology Data Exchange (ETDEWEB)
Cartwright, Susan
1992-04-15
Like any other electrically charged particles, quarks should give out electromagnetic radiation (photons) when they vibrate. One of the physics results from CERN's LEP collider is the first clear observation of this quark radiation from electron-positron collisions. At lower energies this radiation could only be inferred.
International Nuclear Information System (INIS)
Larios, F.
2006-01-01
We give an overview of the physics of the Top quark, from the experimental discovery to the studies of its properties. We review some of the work done on the Electroweak and Flavor Changing couplings associated with the Top quark in the Standard Model and beyond. We will focus on the specific contribution of phycisits working in Mexico and Mexican physicists working abroad
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
The smallest thermal scales in a turbulent channel flow at Prandtl number
International Nuclear Information System (INIS)
Bergant, R.; Tiselj, I.
2004-01-01
For describing the turbulent heat transfer from a wall to a fluid at low Reynolds (Re < 10000) and low Prandtl numbers (Pr < 20) a direct numerical simulation (DNS) can be used, which describes all the length and time scales of the phenomenon. The object of this paper is to find out the influence of the smallest temperature scales on the largest ones, which are responsible for the macro behavior of the near-wall heat transfer. Simulation, performed at Re = 2650 and Pr = 1, was calculated for velocity field with the DNS accuracy and for three different temperature fields. First temperature field, calculated with the DNS accuracy, was used as a reference to the second and third temperature fields where the highest Fourier coefficients in streamwise and spanwise directions were filtered and damped. It means, that the smallest temperature scales were not described with DNS accuracy anymore. New approach shows that results, for at least first and second order statistics, are comparable to the DNS ones without filtering and damping. (author)
Scaling and interaction of self-similar modes in models of high Reynolds number wall turbulence.
Sharma, A S; Moarref, R; McKeon, B J
2017-03-13
Previous work has established the usefulness of the resolvent operator that maps the terms nonlinear in the turbulent fluctuations to the fluctuations themselves. Further work has described the self-similarity of the resolvent arising from that of the mean velocity profile. The orthogonal modes provided by the resolvent analysis describe the wall-normal coherence of the motions and inherit that self-similarity. In this contribution, we present the implications of this similarity for the nonlinear interaction between modes with different scales and wall-normal locations. By considering the nonlinear interactions between modes, it is shown that much of the turbulence scaling behaviour in the logarithmic region can be determined from a single arbitrarily chosen reference plane. Thus, the geometric scaling of the modes is impressed upon the nonlinear interaction between modes. Implications of these observations on the self-sustaining mechanisms of wall turbulence, modelling and simulation are outlined.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).
Platinum clusters with precise numbers of atoms for preparative-scale catalysis.
Imaoka, Takane; Akanuma, Yuki; Haruta, Naoki; Tsuchiya, Shogo; Ishihara, Kentaro; Okayasu, Takeshi; Chun, Wang-Jae; Takahashi, Masaki; Yamamoto, Kimihisa
2017-09-25
Subnanometer noble metal clusters have enormous potential, mainly for catalytic applications. Because a difference of only one atom may cause significant changes in their reactivity, a preparation method with atomic-level precision is essential. Although such a precision with enough scalability has been achieved by gas-phase synthesis, large-scale preparation is still at the frontier, hampering practical applications. We now show the atom-precise and fully scalable synthesis of platinum clusters on a milligram scale from tiara-like platinum complexes with various ring numbers (n = 5-13). Low-temperature calcination of the complexes on a carbon support under hydrogen stream affords monodispersed platinum clusters, whose atomicity is equivalent to that of the precursor complex. One of the clusters (Pt 10 ) exhibits high catalytic activity in the hydrogenation of styrene compared to that of the other clusters. This method opens an avenue for the application of these clusters to preparative-scale catalysis.The catalytic activity of a noble metal nanocluster is tied to its atomicity. Here, the authors report an atom-precise, fully scalable synthesis of platinum clusters from molecular ring precursors, and show that a variation of only one atom can dramatically change a cluster's reactivity.
Large scale Direct Numerical Simulation of premixed turbulent jet flames at high Reynolds number
Attili, Antonio; Luca, Stefano; Lo Schiavo, Ermanno; Bisetti, Fabrizio; Creta, Francesco
2016-11-01
A set of direct numerical simulations of turbulent premixed jet flames at different Reynolds and Karlovitz numbers is presented. The simulations feature finite rate chemistry with 16 species and 73 reactions and up to 22 Billion grid points. The jet consists of a methane/air mixture with equivalence ratio ϕ = 0 . 7 and temperature varying between 500 and 800 K. The temperature and species concentrations in the coflow correspond to the equilibrium state of the burnt mixture. All the simulations are performed at 4 atm. The flame length, normalized by the jet width, decreases significantly as the Reynolds number increases. This is consistent with an increase of the turbulent flame speed due to the increased integral scale of turbulence. This behavior is typical of flames in the thin-reaction zone regime, which are affected by turbulent transport in the preheat layer. Fractal dimension and topology of the flame surface, statistics of temperature gradients, and flame structure are investigated and the dependence of these quantities on the Reynolds number is assessed.
Possible reason why leptons are lighter than quarks
International Nuclear Information System (INIS)
Volkas, R.R.
1994-01-01
The minimal model of spontaneously broken leptonic colour and discrete quark-lepton symmetry predicts that charged leptons have the same masses as their partner charge +2/3 quarks up to small radiative corrections. By invoking a different pattern of symmetry braking, a similar model can be constructed with the structural feature that charged leptons have to be lighter than their partner quarks because of fermion mixing effects. As well as furnishing a new model-building tool, this is phenomenologically interesting because the scale of the new physics responsible for the quark-lepton mass hierarchy could be as low as several hundred GeV. 8 refs
Search for Excited Quarks in ep Collisions at HERA
Aaron, F D; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naroska, B; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Sheviakov, I; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R
2009-01-01
A search for excited quarks is performed using the full ep data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb^-1. The electroweak decays of excited quarks q* -> q gamma, q* -> q Z and q* -> q W with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches.
Critical parameters of Quark-Hadron phase transition with interacting and massive quarks
International Nuclear Information System (INIS)
Singh, C.P.; Patra, B.K.
1994-06-01
Current techniques to simulate the dynamical behaviour of Quark-Gluon Plasma (QGP) reveal that the order of the phase transition as well as the values of the critical parameters depend on the number of quark flavours as well as on the quark-masses included in the simulation. We attempt to show here the effects of the number of quark flavours and quark-masses on critical parameters by using the perturbative, finite temperature field theory to g 3 s order in the strong coupling g s . We treat the hadrons as particles with finite size and its implications on the equation of state for hadron gas are studied. We find that the critical temperature T c is lowered by 9 MeV as we move from two to three quark flavours. The nature of the phase transition always remains as first order. However, the inclusion of quark-masses in our calculation does not affect the result much. (author). 14 refs, 3 figs
About the damping of quark-hadron form factors in relative quark momentum
International Nuclear Information System (INIS)
Lewin, K.; Kallies, W.
1979-01-01
A problem of sufficient damping of hadron bound states at nonasymptotic relative quark momenta is discussed. This phenomenon is considered in the connection with the power scaling beginning at momentum transfer | t | >= 2-3 GeV 2 . Damping of hadron bound states is obtained on the basis of a behaviour of four-quark Green's functions in the momentum transfer which is required by diffraction scattering
Quark mean field theory and consistency with nuclear matter
International Nuclear Information System (INIS)
Dey, J.; Dey, M.; Frederico, T.; Tomio, L.
1990-09-01
1/N c expansion in QCD (with N c the number of colours) suggests using a potential from meson sector (e.g. Richardson) for baryons. For light quarks a σ field has to be introduced to ensure chiral symmetry breaking ( χ SB). It is found that nuclear matter properties can be used to pin down the χ SB-modelling. All masses, M N , m σ , m ω are found to scale with density. The equations are solved self consistently. (author). 29 refs, 2 tabs
Differences between quark and gluon jets as seen at LEP
International Nuclear Information System (INIS)
Tasevsky, M.
2001-01-01
The differences between quark and gluon jets are studied using LEP results on jet widths, scale dependent multiplicities, ratios of multiplicities, slopes and curvatures and fragmentation functions. It is emphasized that the observed differences stem primarily from the different quark and gluon colour factors
Differences between Quark and Gluon jets as seen at LEP
Tasevsky, Marek
2001-01-01
The differences between quark and gluon jets are studied using LEP results on jet widths, scale dependent multiplicities, ratios of multiplicities, slopes and curvatures and fragmentation functions. It is emphasized that the observed differences stem primarily from the different quark and gluon colour factors.
Constraints on nucleon quark models from deep inelastic scattering data
International Nuclear Information System (INIS)
Nataf, R.S.
1980-12-01
Within the context of Q.C.D. it is assumed that quarks and gluons have rather sharply defined masses in the confinement region. Then the experimental data on structure functions give an upper limit to the light quark masses approximately 600MeV. Target mas corrections to scaling depend on further approximations
Tests of Full-Scale Helicopter Rotors at High Advancing Tip Mach Numbers and Advance Ratios
Biggers, James C.; McCloud, John L., III; Stroub, Robert H.
2015-01-01
As a continuation of the studies of reference 1, three full-scale helicopter rotors have been tested in the Ames Research Center 40- by SO-foot wind tunnel. All three of them were two-bladed, teetering rotors. One of the rotors incorporated the NACA 0012 airfoil section over the entire length of the blade. This rotor was tested at advance ratios up to 1.05. Both of the other rotors were tapered in thickness and incorporated leading-edge camber over the outer 20 percent of the blade radius. The larger of these rotors was tested at advancing tip Mach numbers up to 1.02. Data were obtained for a wide range of lift and propulsive force, and are presented without discussion.
Random number generators for large-scale parallel Monte Carlo simulations on FPGA
Lin, Y.; Wang, F.; Liu, B.
2018-05-01
Through parallelization, field programmable gate array (FPGA) can achieve unprecedented speeds in large-scale parallel Monte Carlo (LPMC) simulations. FPGA presents both new constraints and new opportunities for the implementations of random number generators (RNGs), which are key elements of any Monte Carlo (MC) simulation system. Using empirical and application based tests, this study evaluates all of the four RNGs used in previous FPGA based MC studies and newly proposed FPGA implementations for two well-known high-quality RNGs that are suitable for LPMC studies on FPGA. One of the newly proposed FPGA implementations: a parallel version of additive lagged Fibonacci generator (Parallel ALFG) is found to be the best among the evaluated RNGs in fulfilling the needs of LPMC simulations on FPGA.
Quark confinement and the quark model
International Nuclear Information System (INIS)
Kuti, J.
1977-01-01
The CERN-JINR School of Physics is meant to give young experimental physicists and introduction to the theoretical aspects of recent advances in elementary particle physics. The purpose of the lectures contained in this paper is to discuss recent work on the quark model and its applications to hadron spectroscopy and some high-energy phenomena. (Auth.)
Vilella, Kenny; Deschamps, Frederic
2018-04-01
Thermal evolution of terrestrial planets is controlled by heat transfer through their silicate mantles. A suitable framework for modelling this heat transport is a system including bottom heating (from the core) and internal heating, e.g., generated by secular cooling or by the decay of radioactive isotopes. The mechanism of heat transfer depends on the physical properties of the system. In systems where convection is able to operate, two different regimes are possible depending on the relative amount of bottom and internal heating. For moderate internal heating rates, the system is composed of active hot upwellings and cold downwellings. For large internal heating rates, the bottom heat flux becomes negative and the system is only composed of active cold downwellings. Here, we build theoretical scaling laws for both convective regimes following the approach of Vilella & Kaminski (2017), which links the surface heat flux and the temperature jump across both the top and bottom thermal boundary layer (TBL) to the Rayleigh number and the dimensionless internal heating rate. Theoretical predictions are then verified against numerical simulations performed in 2D and 3D-Cartesian geometry, and covering a large range of the parameter space. Our theoretical scaling laws are more successful in predicting the thermal structure of systems with large internal heating rates than that of systems with no or moderate internal heating. The differences between moderate and large internal heating rates are interpreted as differences in the mechanisms generating thermal instabilities. We identified three mechanisms: conductive growth of the TBL, instability impacting, and TBL erosion, the last two being present only for moderate internal heating rates, in which hot plumes are generated at the bottom of the system and are able to reach the surface. Finally, we apply our scaling laws to the evolution of the early Earth, proposing a new model for the cooling of the primordial magma ocean
International Nuclear Information System (INIS)
Chaichian, M.; Hayashi, M.; Honkaranta, T.
1980-01-01
We consider in QCD the second order, in gluon-quark coupling constant, contribution of the quark-quark scatte-ring (bremsstrahlung) to the transverse momentum distribution of muon pairs produced in proton-proton collisions. In certain kinematical regions accesible to experimental tests, this contribution is quite large in comparison with the first order calculations. This happens for a specific choice of scale violating structure functions which fit the deep inelastic data. Thus the first order QCD calcula-tion alone is not conclusive in trying to fit the data -one must necessarily check the effect of the second order quark-quark scattering as compared with the first order quark-gluon and the quark-antiquark scattering. This remark concerns also the case when in the first order diagrams the effect of primordial transverse momentum of partons is included as well as the case when the first order is replaced by DDT type of formulae. Mass regularization and different prescriptions for the constant term in q → g + q vertex are considered. Results are presented for the energies √s=6.5, 27, 63, 800 GeV and are compared with experiment. Implications of these results for the detection of W +- -mesons via psub(T) distribution of their decay products μ +- in proton-proton collisions are mentioned. (author)
Fritzsch, Harald
1983-01-01
Quark rossi, verdi e blu ; quark dotati di stranezza e di incanto ; quark 'su' e 'giù' : sembra che i fisici delle particelle giochino a confondere la curiosità del profano, con queste denominazioni fantasiose. Che cosa significano ? e, soprattutto, i quark sono i costituenti davvero elementari della materia ?
Top Quark Properties at Tevatron
Energy Technology Data Exchange (ETDEWEB)
Lysák, Roman [Prague, Inst. Phys.
2017-11-27
The latest CDF and D0 experiment measurements of the top quark properties except the top quark mass are presented. The final combination of the CDF and D0 forward-backward asymmetry measurements is shown together with the D0 measurements of the inclusive top quark pair cross-section as well as the top quark polarization.
Orbital angular momentum parton distributions in quark models
International Nuclear Information System (INIS)
Scopetta, S.; Vento, V.
2000-01-01
At the low energy, hadronic, scale we calculate Orbital Angular Momentum (OAM) twist-two parton distributions for the relativistic MIT bag model and for nonrelativistic quark models. We reach the scale of the data by leading order evolution in perturbative QCD. We confirm that the contribution of quarks and gluons OAM to the nucleon spin grows with Q 2 , and it can be relevant at the experimental scale, even if it is negligible at the hadronic scale, irrespective of the model used. The sign and shape of the quark OAM distribution at high Q 2 may depend strongly on the relative size of the OAM and spin distributions at the hadronic scale. Sizeable quark OAM distributions at the hadronic scale, as proposed by several authors, can produce the dominant contribution to the nucleon spin at high Q 2 . (author)
A chiral quark model of the nucleon
International Nuclear Information System (INIS)
Wakamatsu, M.; Yoshiki, H.
1991-01-01
The baryon-number-one extended solution of a chiral quark lagrangian is obtained in the stationary-phase approximation with full inclusion of the sea-quark degrees of freedom. The collective quantization method is then applied to this static solution to obtain the nucleon (and Δ) state with the definite spin and isospin. A fundamental quantity appearing in this quantization procedure is the moment of inertia of the soliton system. We evaluate this quantity without recourse to the derivative expansion, by performing the necessary double sum over all the positive- and negative-energy quark orbitals in the mean field potential. Closed formulas are-derived for the nucleon (and Δ) matrix elements of arbitrary quark bilinear operators. These formulas are then used for calculating various nucleon observables in a nonperturbative manner with inclusion of the sea-quark effects. An especially interesting observable is the spin expectation value of the proton related to the recent EMC experiment. We derive the proton spin sum rule, and then explicitly evaluate the detailed contents of this sum rule. The proton spin analysis is shown to be particularly useful for clarifying the underlying dynamical content of the Skyrme model at quark level, thereby providing us with valuable information about its utility and limitation. (orig.)
International Nuclear Information System (INIS)
Anisovich, V.V.
1989-06-01
Using the language of the quarks and gluons for description of the soft hadron physics it is necessary to take into account two characteristic phenomena which prevent one from usage of QCD Lagrangian in the straightforward way, chiral symmetry breaking, and confinement of colour particles. The topics discussed in this context are: QCD in the domain of soft processes, phenomenological Lagrangian for soft processes and exotic mesons, spectroscopy of low-lying hadrons (mesons, baryons and mesons with heavy quarks - c,b -), confinement forces, spectral integration over quark masses. (author) 3 refs.; 19 figs.; 3 tabs
Energy Technology Data Exchange (ETDEWEB)
Goldhaber, J.
1986-11-13
The paper concerns the experimental search for quark-gluon plasma. The theory of a quark-gluon plasma is first given. Then the method which researchers hope will create the quark-gluon plasma is described; the idea is to use heavy ion beams in, the CERN SPS. The CERN 'heavy-ion programme' involves research groups mainly from CERN, Lawrence Berkeley Laboratory and Gellsellschaft fuer Schwerionenforschung. The experiments in the research programme are outlined, together with the detector equipment employed in the experiments.
A semiclassical model for quark jet fragmentation
International Nuclear Information System (INIS)
Andersson, B.; Gustafson, G.; Peterson, C.
1979-01-01
A semiclassical model is presented for the way the energy of a fast quark is transformed into observable hadrons. It reproduces the features of 1+1 dimensional QED (the Schwinger model) concerning a flat rapidity distribution in the central region. It also reproduces results from phenomenological considerations, which, based upon scaling, predict that meson formation in the fragmentation region can be described by an iterative scheme, implying a set of coupled integral equations. In particular the model predicts that the probability to find a meson containing the leading quark is independent of the Feynman scaling variable z. The iterative structure corresponds to a Brownian motion with relevance both to the cofinement problems and to the distribution of mass in the quark jet. (orig.) [de
Effect of soft mode on shear viscosity of quark matter
International Nuclear Information System (INIS)
Fukutome, Takahiko; Iwasaki, Masaharu
2008-01-01
We calculate the shear viscosity of quark matter at finite temperature and density. If we assume that the quark interacts with the soft mode, which is a collective mode of a quark-antiquark pair, the self-energy of the quark is calculated by quasi-particle random phase approximation. It is shown that its imaginary part is large and its mean free path is short. With the use of the Kubo formula, the shear viscosity of quark matter decreases. The Reynolds number of quark matter is estimated to be about 10. As temperature increases, shear viscosity increases gradually for T>200 MeV. Moreover it is shown that the shear viscosity also increases with the chemical potential for μ>200 MeV. (author)
Top quark measurements at ATLAS
Grancagnolo, Sergio; The ATLAS collaboration
2017-01-01
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, this gives us the unique opportunity to probe the properties of bare quarks at the Large Hadron Collider. This talk will present highlights of a few recent precision measurements by the ATLAS Collaboration of the top quark using 13 TeV and 8 TeV collision data: top-quark pair and single top production cross sections including differential distributions will be presented alongside top quark properties measurements. These measurements, including results using boosted top quarks, probe our understanding of top quark production in the TeV regime. Measurements of the top quark mass and searches for rare top quark decays are also presented.
Top quark measurements at ATLAS
AUTHOR|(INSPIRE)INSPIRE-00041686; The ATLAS collaboration
2017-01-01
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, it allows us to probe the properties of bare quarks at the Large Hadron Collider. Highlights of a few recent precision measurements by the ATLAS Collaboration of the top quark using 13 TeV and 8 TeV collision data will be presented: top-quark pair and single top production cross sections including differential distributions will be presented alongside measurements of top-quark properties, including results using boosted top quarks, probe our understanding of top-quark production in the TeV regime. Measurements of the top-quark mass and searches for rare top quark decays are also presented.
Spinodal instability of baryon-rich quark matter
International Nuclear Information System (INIS)
Li, Feng; Ko, Che Ming
2017-01-01
The spinodal instabilities of both confined and expanding baryon-rich quark matters are studied in a transport model derived from the Nambu-Jona-Lasino model. Appreciable higher-order density moments are seen as a result of the first-order phase transition in both cases. The skewness of the quark number event-by-event distribution in a small subvolume of the system becomes appreciable for the confined quark matter. For the expanding quark matter, the density fluctuations lead to enhanced anisotropic flows and dilepton yield. (paper)
Scaling behaviour in the number of criminal acts committed by individuals
Cook, Will; Ormerod, Paul; Cooper, Ellie
2004-07-01
We examine the distribution of the extent of criminal activity by individuals in two widely cited data bases. The Cambridge Study in Delinquent Development records criminal convictions amongst a group of working class youths in the UK over a 14 year period. The Pittsburgh Youth Study measures self-reported criminal acts over intervals of six months or a year in three groups of boys in the public school system in Pittsburgh, PA. The range of the data is very substantially different between these two measures of criminal activity, one of which is convictions and the other self-reported acts. However, there are many similarities between the characteristics of the data sets. A power law relationship between the frequency and rank of the number of criminal acts describes the data well in both cases, and fits the data better than an exponential relationship. Power law distributions of macroscopic observables are ubiquitous in both the natural and social sciences. They are indicative of correlated, cooperative phenomena between groups of interacting agents at the microscopic level. However, there is evidence of a bimodal distribution, again in each case. Excluding the frequency with which zero crimes are committed or reported reduces the absolute size of the estimated exponent in the power law relationship. The exponent is virtually identical in both cases. A better fit is obtained for the tail of the distribution. In other words, there appears to be a subtle deviation from straightforward power law behaviour. The description of the data when the number of boys committing or reporting zero crimes are excluded is different from that when they are included. The crucial step in the criminal progress of an individual appears to be committing the first act. Once this happens, the number of criminal acts committed by an individual can take place on all scales.
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.
International Nuclear Information System (INIS)
Luttrell, S.P.; Wada, S.; Webber, B.R.
1981-01-01
We calculate the leading order Wilson coefficient functions of the four-quark operators in the current product expansion. The process dependence of the contributions of the four-quark operators is given, and it is argued that they are likely to be negative. It is also argued that the spin (n) dependence of the ratio of the four-quark term to the twist-two terms is linear in n (or at most proportional n log n), though the number of independent four-quark operators grows like n 2 . (orig.)
Strong interactions - quark models
International Nuclear Information System (INIS)
Goto, M.; Ferreira, P.L.
1979-01-01
The variational method is used for the PSI and upsilon family spectra reproduction from the quark model, through several phenomenological potentials, viz.: linear, linear plus coulomb term and logarithmic. (L.C.) [pt
Multileptons from heavy quarks
International Nuclear Information System (INIS)
Phillips, R.J.N.
1984-03-01
The paper is concerned with a brief look at the various multilepton signals that are expected at p-barp colliders from the production and cascade decay of top quarks, plus the backgrounds from b and c production. (author)
International Nuclear Information System (INIS)
Roberts, R.G.
1984-11-01
The paper concerns the behaviour of quarks in nuclei. Confinement size changes and dynamical rescaling; A dependence; low-x region; gluons and confinement size; and nucleons in a nucleus; are all discussed. (U.K.)
International Nuclear Information System (INIS)
Hasenfratz, P.; Kuti, J.
1978-01-01
The quark bag model is reviewed here with particular emphasis on spectroscopic applications and the discussion of exotic objects as baryonium, gluonium, and the quark phase of matter. The physical vacuum is pictured in the model as a two-phase medium. In normal phase of the vacuum, outside hadrons, the propagation of quark and gluon fields is forbidden. When small bubbles in a second phase are created in the medium of the normal phase with a characteristic size of one fermi, the hadron constituent fields may propagate inside the bubbles in normal manner. The bubble (bag) is stabilized against the pressure of the confined hadron constituent fields by vacuum pressure and surface tension. Inside the bag the colored quarks and gluons are governed by the equations of quantum chromodynamics. (Auth.)
International Nuclear Information System (INIS)
Guersey, F.
1974-01-01
A mathematical framework based on octonions is developed for the description of the color quark scheme in which quarks are unobservable, the color SU(3) is exact, and only color singlets correspond to observable hadrons. The fictitious Hilbert space in which quarks operate is taken to be a space of vectors with octonion components. This space admits as a gauge group an exact SU(3) identified with the color SU/sub C/(3). Because of the nonassociativity of the underlying algebra, nonsinglet representations of SU/sub C/(3) are unobservable, while the subspace of color singlets satisfies associativity along with conditions for observability. Octonion quark fields satisfy the commutation relations of parafermions of order 3, leading to the correct SU(6) multiplets for hadrons. (U.S.)
International Nuclear Information System (INIS)
Anon.
1995-01-01
Nine months after a careful announcement of tentative evidence for the long-awaited sixth 'top' quark, physicists from the CDF and DO experiments at Fermilab's Tevatron proton-antiproton collider declared on 2 March that they had finally discovered the top quark. Last year (June 1994, page 1), the CDF experiment at the Tevatron reported a dozen candidate top events. These, said CDF, had all the characteristics expected of top, but the difficulties of extracting the tiny signal from a trillion proton-antiproton collisions made them shy of claiming a discovery. For its part, the companion DO Tevatron experiment reported a few similar events but were even more guarded about their interpretation as top quarks. Just after these hesitant announcements, performance at the Tevatron improved dramatically last summer. After the commissioning of a new linear accelerator and a magnet realignment, the machine reached a new world record proton-antiproton collision luminosity of 1.28 x 10 31 per sq cm per s, ten times that originally planned. Data began to pour in at an unprecedented rate and the data sample grew to six trillion collisions. Luminosity has subsequently climbed to 1.7 x 10 31 . The top quark is the final letter in the alphabet of Standard Model particles. According to this picture, all matter is composed of six stronglyinteracting subnuclear particles, the quarks, and six weakly interacting particles, the leptons. Both sextets are neatly arranged as three pairs in order of increasing mass. The fifth quark, the 'beauty' or 'b' quark, was also discovered at Fermilab, back in 1977. Since then physicists have been eagerly waiting for the top to turn up, but have been frustrated by its heaviness - the top is some 40 times the mass of its 'beautiful' partner. Not only is the top quark the heaviest by far, but it is the only quark which has been actively hunted. After the quarry was glimpsed last year, the net has now been
Are quarks and leptons composite
International Nuclear Information System (INIS)
Harari, H.
1982-01-01
The possibility that quarks and leptons are composite was studied. A line of reasoning was pursued which followed several steps. The standard model was assumed and the need to go beyond it was demonstrated. Different classes of ideas were considered. The notion of compositeness and its general difficulties, mainly the scale problem, were studied. A connection between composite massless fermions and an unbroken chiral symmetry was assumed. A general framework based on hypercolor and a chiral symmetry was established. The general requirements for a candidate model were established. A minimal scheme was found and its successes and failures were studied. (HK)
International Nuclear Information System (INIS)
Shirkov, D.V.
1982-01-01
In this paper recent studies of invariant QCD coupling anti asub(s)(Qsup(2)) in the 2-loop approximation with account of fermionic mass effects are summarized. The main results are: An explicit expression for anti asub(s)(Qsup(2)) in the 2-loop approximation with accurate account of heavy quark masses. A quantitative analysis on the basis of the above-mentioned expression for anti asub(s)(Qsup(2)) of the energy dependence of the scale QCD parameter ν and the conclusion about its inadequacy in the modern energy range
Power corrections from decoupling of the charm quark
Knechtli, Francesco; Korzec, Tomasz; Leder, Björn; Moir, Graham; Alpha Collaboration
2017-11-01
Decoupling of heavy quarks at low energies can be described by means of an effective theory as shown by S. Weinberg in Ref. [1]. We study the decoupling of the charm quark by lattice simulations. We simulate a model, QCD with two degenerate charm quarks. In this case the leading order term in the effective theory is a pure gauge theory. The higher order terms are proportional to inverse powers of the charm quark mass M starting at M-2. Ratios of hadronic scales are equal to their value in the pure gauge theory up to power corrections. We show, by precise measurements of ratios of scales defined from the Wilson flow, that these corrections are very small and that they can be described by a term proportional to M-2 down to masses in the region of the charm quark mass.
DEFF Research Database (Denmark)
Sørensen, Paul Haase; Taylor, John C.
1984-01-01
Processes with coloured particles in the initial state are generally infrared divergent. We investigate the effect of this on processes with colourless particles in the initial state, when the amplitude is near an intermediate quark pole. The result is a characteristic logarithmic depedence...... on the 'binding energy'(even though spectator interactions are taken into account), and the result is gauge-invariant. Summed to all orders the logarithms could perhaps suppress the quark pole....
Surface structure of quark stars with magnetic fields
Indian Academy of Sciences (India)
We investigate the impact of magnetic fields on the electron distribution of the electrosphere of quark stars. For moderately strong magnetic fields of ∼ 1013 G, quantization effects are generally weak due to the large number density of electrons at surface, but can nevertheless affect the photon emission properties of quark ...
Twisted mass lattice QCD with non-degenerate quark masses
International Nuclear Information System (INIS)
Muenster, Gernot; Sudmann, Tobias
2006-01-01
Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term is considered in the framework of chiral perturbation theory. For two and three numbers of quark flavours, respectively, with non-degenerate quark masses the pseudoscalar meson masses and decay constants are calculated in next-to-leading order including lattice effects quadratic in the lattice spacing a
Multiple production of hadrons at high energies in the model of quark-gluon strings
International Nuclear Information System (INIS)
Kaidalov, A.B.; Ter-Martirosyan, K.A.
1983-01-01
Multiple production of hadrons at high energies is considered in the framework of the approach based on a picture of formation and subsequent fission of the quark-gluon strings, corresponding to the Pomeron with αsub(P)(0) > 1. The topological (1/nsub(f))-expansion and the colour-tube model is used. Inclusive cross-sections are expressed in therms of the structure functions and fragmentation functions of quarks and their limiting values are in an agreement with the results of the reggeon theory. It is pointed out that an account of rapidity fluctuations of the ends of the quark-gluon strings, connected to valence or sea quarks, allows one to explain a number of characteristic features of the multiple production of hadrons. In particular the model, which takes into account multipomeron configurations, reproduces the experimentally observed rise of inclusive spectra in a central region and well describes both rapidity and multiplicity distributions of charged particles up to energies of the SPS-collider. It is shown that in this approach the KNO-scaling is only approximately satisfied and the pattern of its violation at energies √ s approximately 10 3 GeV is predicted. Inclusive spectra are investigated in the whole region 0 or approximately 0.1) Feynman scaling is violated only logarithmically and deviations from it are very rsmall at s 3 +10 4 GeV
Scaling of nuclear modification factors for hadrons and light nuclei
Energy Technology Data Exchange (ETDEWEB)
Zhou, C.S. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); University of Chinese Academy of Sciences, Beijing (China); Ma, Y.G. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); ShanghaiTech University, Shanghai (China); Zhang, S. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China)
2016-12-15
The number of constituent quarks (NCQ) scaling for hadrons and the number of constituent nucleons (NCN) scaling for light nuclei are proposed for nuclear modification factors (R{sub cp}) of hadrons and light nuclei, respectively, according to the experimental investigations in relativistic heavy-ion collisions. Based on the coalescence mechanism the scalings are performed for pions and protons at the quark level, and for light nuclei d(anti d) and {sup 3}He at the nucleonic level, respectively, formed in Au+Au and Pb+Pb collisions, and a nice scaling behaviour emerges. The NCQ or NCN scaling law of R{sub cp} can be, respectively, taken as a probe for the quark or nucleon coalescence mechanism for the formation of hadron or light nuclei in relativistic heavy-ion collisions. (orig.)
Scaling of Polymer Degradation Rate within a High-Reynolds-Number Turbulent Boundary Layer
Elbing, Brian; Solomon, Michael; Perlin, Marc; Dowling, David; Ceccio, Steven
2009-11-01
An experiment conducted at the U.S. Navy's Large Cavitation Channel on a 12.9 m long flat-plate test model produced the first quantitative measurements of polymer molecular weight within a turbulent boundary layer. Testing was conducted at speeds to 20 m/s and downstream distance based Reynolds numbers to 220 million. These results showed that the rate of polymer degradation by scission of the polymer chains increases with increased speed, downstream distance and surface roughness. With the surface fully rough at 20 m/s there was no measureable level of drag reduction at the first measurement location (0.56 m downstream of injection). These results are scaled with the assumption that the rate of degradation is dependent on the polymer residence time in the flow and the local shear rate. A successful collapse of the data within the measurement uncertainty was achieved over a range of flow speed (6.6 to 20 m/s), surface roughness (smooth and fully rough) and downstream distance from injection (0.56 to 9.28 m).
Inflating metastable quark-gluon plasma universe
International Nuclear Information System (INIS)
Jenkovszky, L.L.; Kaempfer, B.; Sysoev, V.M.
1990-01-01
We show within the Friedmann model with the equation of state p(T)=aT 4 -AT that our universe has expanded exponentially when it was in a metastable quark-gluon plasma state. The scale factor during that epoch increased by many orders of magnitude. 13 refs.; 5 figs
Nuclear and quark matter at high temperature
Energy Technology Data Exchange (ETDEWEB)
Biro, Tamas S. [H.A.S. Wigner Research Centre for Physics, Budapest (Hungary); Jakovac, Antal [Roland Eotvos University, Budapest (Hungary); Schram, Zsolt [University of Debrecen, Institute for Theoretical Physics, Debrecen (Hungary)
2017-03-15
We review important ideas on nuclear and quark matter description on the basis of high-temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the -partially still open- problems of the hadronization process. (orig.)
Important configurations in six-quark N-N states. II. Current quark model
International Nuclear Information System (INIS)
Stancu, F.; Wilets, L.
1989-01-01
Quark basis states constructed from molecular-type orbitals were shown previously to be more convenient to use than cluster model states for N-N processes. The usual cluster model representation omits configurations which emerge naturally in a molecular basis which contains the same number of spatial functions. The importance of the omitted states was demonstrated for a constituent quark model. The present work extends the study to the prototypical current quark model, namely the MIT bag. In order to test the expansion for short-range N-N interactions, the eigenstates and eigenenergies of six quarks in a spherical bag, including one-gluon exchange, are calculated. The lowest eigenenergies are lowered significantly with respect to the usual cluster model. This reaffirms the importance of dynamics for obtaining the needed short-range repulsion
Scale and the Evolutionarily Based Approximate Number System: An Exploratory Study
Delgado, Cesar; Jones, M. Gail; You, Hye Sun; Robertson, Laura; Chesnutt, Katherine; Halberda, Justin
2017-01-01
Crosscutting concepts such as "scale, proportion, and quantity" are recognised by U.S. science standards as a potential vehicle for students to integrate their scientific and mathematical knowledge; yet, U.S. students and adults trail their international peers in scale and measurement estimation. Culturally based knowledge of scale such…
Universal parametrization for quark and lepton substructure
International Nuclear Information System (INIS)
Akama, Keiichi; Terazawa, Hidezumi.
1994-01-01
A universal parametrization for possible quark and lepton substructure is advocated in terms of quark and lepton form factors. It is emphasized that the lower bounds on compositeness scale, Λ c , to be determined experimentally strongly depend on their definitions in composite models. From the recent HERA data, it is estimated to be Λ c > 50 GeV, 0.4 TeV and 10 TeV, depending on the parametrizations with a single-pole form factor, a contact interaction and a logarithmic form factor, respectively. (author)
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
Prediction of new Quarks, Generations and Quark Masses
Lach, Thedore
2002-04-01
The Standard model currently suggests no relationship between the quark and lepton masses. The CBM (model) of the nucleus has resulted in the prediction of two new quarks, an up quark mass of 237.31 MeV/c2 and a dn quark mass of 42.392 MeV/c2. These two new quarks help explain the numerical relationship between all the quark and lepton masses in a single function. The mass of each SNU-P (quark or lepton) is just the geometric mean of two related SNU-Ps, either in the same generation or in the same family. This numerology predicts the following masses for the electron family: 0.511000 (electron), 7.743828 (predicted), 117.3520, 1778.38, 26950.08 MeV. The resulting slope of these masses when plotted on semi log paper is "e" to 5 significant figures using the currently accepted mass for Tau. This theory suggests that all the "dn like" quarks have a mass of just 10X multiples of 4.24 MeV (the mass of the "d" quark). The first 3 "up like" quark masses are 38, 237 and 1500 MeV. This theory also predicts a new heavy generation with a lepton mass of 27 GeV, a "dn like" quark of 42.4 GeV, and an "up like" quark of 65 GeV. Significant evidence already exists for the existence of these quarks, and lepton.
A QCD derivation of the additive quark model from two and three gluon exchanges
International Nuclear Information System (INIS)
Lipkin, H.J.
1982-06-01
The contributions to the Pomeron from two and three gluon exchanges are shown to give the correct combinatorial factors for the additive quark model relation between meson and baryon Pomeron couplings, even though two-quark and three-quark operators are involved. Similar results hold for the contributions to hadron masses from three-gluon vertices as well as one-gluon exchange. The color algebra reduces the multiquark couplings to a linear function of quark number. (author)
Essence of the Vacuum Quark Condensate
International Nuclear Information System (INIS)
Brodsky, Stanley
2010-01-01
We show that the chiral-limit vacuum quark condensate is qualitatively equivalent to the pseudoscalar meson leptonic decay constant in the sense that they are both obtained as the chiral-limit value of well-defined gauge-invariant hadron-to-vacuum transition amplitudes that possess a spectral representation in terms of the current-quark mass. Thus, whereas it might sometimes be convenient to imagine otherwise, neither is essentially a constant mass-scale that fills all spacetime. This means, in particular, that the quark condensate can be understood as a property of hadrons themselves, which is expressed, for example, in their Bethe-Salpeter or light-front wavefunctions.
Color quarks as a new stage of knowledge of microcosm
International Nuclear Information System (INIS)
Bogolyubov, N.N.
1985-01-01
The theory of color quarks is discussed in a popular form. The idea of color quarks lies in the main principle of modern conceptions of the world of elementary particles and atomic nuclei. In 1965 in the studies of A.N. Tavkhelidze, B.V. Struminsky and N.N. Bogolyubov as well as independently in the studies of M. Khan, E.Nambu and J.Miyamote the hypothesis on the presence of a new quantum number of quarks called subsequently color has been suggested. For each type of quarks with specified values of isotopic spin, electrical charge and strangeness three unitary-equivalent states which differ in the values of the new quantum number - color exist. The hypothesis of color quarks turned out cardinal idea which cleared the way to the solution of fundamental problems of the theory of elementary particles
QCD as a basis for quark and nuclear forces
International Nuclear Information System (INIS)
Close, F.E.
1983-01-01
This chapter examines quarks in nucleons and the ideas behind the quantum chromodynamic (QCD) theory of their interactions. Compares nuclei and nucleons, and examines length or energy scales in physics. Reviews the present knowledge about the basic building blocks: quarks and leptons. Discusses color, building colorless hadrons, effects of color inside hadrons (spin flavor correlations, magnetic moments), color as the source of a field theory (molecular and nuclear forces), non-Abelian theories (qualitative features, boson-fermion vertices in SU(N), gauge invariance), renormalization and scaling violation (Lagrangians and renormalization, logs in perturbation theory), and quarks and nuclear forces
Total number of planetary nebulae in different galaxies and the PN distance scale.
Peimbert, M.
1990-12-01
RESUMEN A partir de una muestra de quince galaxias se encuentra que la tasa de natalidad de nebulosas planetarias por unidad de luminosidad, , disminuye al aumentar la luminosidad y al aumentar (B - V)0. Se discuten posibles explicaciones para estos resultados. Se estima el valor de para la Galaxia y a partir de el se encuentra que el numero total de nebulosas planetarias en nuestra galaxia con R de 7200 j 1800. El valor galactico de implica que la mayorfa de las estrellas de masa intermedia pasa por la etapa de nebulosa planetaria. El valor galactico de , la tasa de mortalidad estelar por unidad de luminosidad y la tasa de natalidad de enanas blancas favorecen escalas de distancias largas para nebulosas planetarias, como la de Cudworth (1974) y la de Mallik y Peimbert (1988). ABSTRACT From a sample of fifteen galaxies it is found that the birth rate of PN per unit luminosity, , decreases with increasing luminosity and with increasing (B - V)0 possible reasons for these relationships are discussed. The value for the Galaxy is estimated and, from it, a total number of PN of 7200 # 1800 wid R < 0.64 pc is obtained. The galactic value implies that most of the intermediate mass stars go through the PN stage. The galactic value, the stellar death rate per unit luminosity and the white dwarf birth rate are in favor of long distance scales to PN like those of Cudworth (1974) and Mallik and (1988). Key wonis: NEBULAE.PLANETARY - STARS-EVOLUTION - STARS-SThLIAR STA. S
Dogan, Eda; Hearst, R Jason; Ganapathisubramani, Bharathram
2017-03-13
A turbulent boundary layer subjected to free-stream turbulence is investigated in order to ascertain the scale interactions that dominate the near-wall region. The results are discussed in relation to a canonical high Reynolds number turbulent boundary layer because previous studies have reported considerable similarities between these two flows. Measurements were acquired simultaneously from four hot wires mounted to a rake which was traversed through the boundary layer. Particular focus is given to two main features of both canonical high Reynolds number boundary layers and boundary layers subjected to free-stream turbulence: (i) the footprint of the large scales in the logarithmic region on the near-wall small scales, specifically the modulating interaction between these scales, and (ii) the phase difference in amplitude modulation. The potential for a turbulent boundary layer subjected to free-stream turbulence to 'simulate' high Reynolds number wall-turbulence interactions is discussed. The results of this study have encouraging implications for future investigations of the fundamental scale interactions that take place in high Reynolds number flows as it demonstrates that these can be achieved at typical laboratory scales.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).
Meson Spectroscopy in the Light Quark Sector
De Vita, R.
2014-03-01
Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the qbar q configuration as tetraquarks (qqoverline{qq}), hybrids (qbar qg) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for qbar q states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e+e- annihilation, pbar p annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states. This intense effort is
International Nuclear Information System (INIS)
Rho, Mannque.
1980-04-01
The present status of our understanding of the physics of hadronic (nuclear or neutron) matter under extreme conditions, in particular at high densities is discussed. This is a problem which challenges three disciplines of physics: nuclear physics, astrophysics and particle physics. It is generally believed that we now have a correct and perhaps ultimate theory of the strong interactions, namely quantum chromodynamics (QCD). The constituents of this theory are quarks and gluons, so highly dense matters should be describable in terms of these constituents alone. This is a question that addresses directly to the phenomenon of quark confinement, one of the least understood aspects in particle physics. For nuclear physics, the possibility of a phase change between nuclear matter and quark matter introduces entirely new degrees of freedom in the description of nuclei and will bring perhaps a deeper understanding of nuclear dynamics. In astrophysics, the properties of neutron stars will be properly understood only when the equation of state of 'neutron' matter at densities exceeding that of nuclear matter can be realiably calculated. Most fascinating is the possibility of quark stars existing in nature, not entirely an absurd idea. Finally the quark matter - nuclear matter phase transition must have occured in the early stage of universe when matter expanded from high temperature and density; this could be an essential ingredient in the big-bang cosmology
A Study on Time-Scales Ratio and Turbulent Prandtl Number in Ducts of Industrial Applications
DEFF Research Database (Denmark)
Rokni, Masoud
2006-01-01
is solved using a two-equation heat ﬂux model. The computed results compare satisfactory with the available experimental data. The time-scale ratio R is deﬁned as the ratio between the dynamic time-scale (k/ε) and the scalar time-scale(0.5θθ/εθ). Based on existing DNS data and calculations in this work...... of heat exchangers for various applications area....
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
A quark interpretation of the combinatorial hierarchy
International Nuclear Information System (INIS)
Enqvist, Kari.
1979-01-01
We propose a physical interpretation of the second level of the combinatorial hierarchy in terms of three quarks, three antiquarks and the vacuum. This interpretation allows us to introduce a new quantum number, which measures electromagnetic mass splitting of the quarks. We extend our argument by analogue to baryons, and find some SU(3) and some new mass formulas for baryons. The generalization of our approach to other hierarchy levels is discussed. We present also an empirical mass formula for baryons, which seems to be loosely connected with the combinatorial hierarchy. (author)
Single top quark production at LEP200?
International Nuclear Information System (INIS)
Boos, E.; Ishikawa, T.; Kaneko, T.; Kawabata, S.; Kurihara, Y.; Shimizu, Y.; Tanaka, H.
1994-01-01
A complete tree-level calculation of the reaction e + e - → e + ν e anti tb (e - anti ν e t anti b) in the electroweak standard theory in the LEP200 energy range is presented. For top quark masses in the range 130 to 190 GeV the cross sections are found to be in the order of 10 -5 to 10 -6 pb. Therefore, the number of single top quark events is expected to be negligible even with an integrated luminosity of L = 500 pb -1 . It is further demonstrated that the Weizsaecker-Williams approximation is approaching the accurate cross section calculations resonably well. (orig.)
The fourth family of quarks and leptons
International Nuclear Information System (INIS)
Cline, D.B.; Soni, A.
1987-01-01
This book presents the proceedings of The Fourth Family of Quarks and Leptons. Topics covered include: Missing Transverse Energy Events and a Search for Additional Neutrino Families and a Fourth-Generation Lepton; Cosmological Limit on the Number of Families; and Charmed Baryon Decay
The stokes number approach to support scale-up and technology transfer of a mixing process
Willemsz, T.A.; Hooijmaijers, R.; Rubingh, C.M.; Frijlink, H.W.; Vromans, H.; Voort Maarschalk, K. van der
2012-01-01
Transferring processes between different scales and types of mixers is a common operation in industry. Challenges within this operation include the existence of considerable differences in blending conditions between mixer scales and types. Obtaining the correct blending conditions is crucial for
The Stokes number approach to support scale-up and technology transfer of a mixing process
Willemsz, Tofan A; Hooijmaijers, Ricardo; Rubingh, Carina M; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees
Transferring processes between different scales and types of mixers is a common operation in industry. Challenges within this operation include the existence of considerable differences in blending conditions between mixer scales and types. Obtaining the correct blending conditions is crucial for
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.
Quark vs Gluon Jet Tagging at ATLAS
Rubbo, Francesco; The ATLAS collaboration
2017-01-01
Distinguishing quark-initiated from gluon-initiated jets is useful for many measurements and searches at the LHC. We present a quark-initiated versus gluon-initiated jet tagger from the ATLAS experiment using the number of reconstructed charged particles inside the jet. The measurement of the charged-particle multiplicity inside jets from Run 1 is used to derive uncertainties on the tagger performance for Run 2. With an efficiency of 60% to select quark-initiated jets, the efficiency to select gluon-initiated jets is between 10 and 20% across a wide range in jet pT up to 1.5 TeV with about an absolute 5% systematic uncertainty on the efficiencies. In addition, we also present preliminary studies on a tagger for the ATLAS experiment using the full radiation pattern inside a jet processed as images in deep neural network classifiers.
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
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
Mulders, Martijn
2016-01-01
Ever since the discovery of the top quark at the Tevatron collider in 1995 the measurement of its mass has been a high priority. As one of the fundamental parameters of the Standard Theory of particle physics, the precise value of the top quark mass together with other inputs provides a test for the self-consistency of the theory, and has consequences for the stability of the Higgs field that permeates the Universe. In this review I will briefly summarize the experimental techniques used at the Tevatron and the LHC experiments throughout the years to measure the top quark mass with ever improving accuracy, and highlight the recent progress in combining all measurements in a single world average combination. As experimental measurements became more precise, the question of their theoretical interpretation has become important. The difficulty of relating the measured quantity to the fundamental top mass parameter has inspired alternative measurement methods that extract the top mass in complementary ways. I wil...
Signatures of quark-gluon plasma production
International Nuclear Information System (INIS)
Gyulassy, M.
1985-01-01
A critical analysis of a variety of proposed signatures for quark-gluon formation in ultrarelativistic nuclear collisions is given. The authors emphasize that longitudinal growth rather than the nuclear radius controls the time scales for expansion. The author pointed out the qualitative difference of the evolution of the plasma produced in the stopping regime E approx. 10 GeV/nucleon and the scaling regime E > 1 TeV/nucleon. This difference reflects itself in the the rmal profile function
The Quark's Model and Confinement
Novozhilov, Yuri V.
1977-01-01
Quarks are elementary particles considered to be components of the proton, the neutron, and others. This article presents the quark model as a mathematical concept. Also discussed are gluons and bag models. A bibliography is included. (MA)
Heavy quarks at hadron colliders
International Nuclear Information System (INIS)
Paige, F.E.
1989-01-01
This paper discusses a conference at which the standard model requiring the existence of a top quark + to form a weak isospin doublet with the b quark is explored. Collaboration suggestions are offered. Results are explored
International Nuclear Information System (INIS)
Metzger, M.
2006-01-01
Reynolds number effects on relevant length and time scales in the near-wall region of a canonical turbulent boundary layer are investigated. Well resolved measurements in the atmospheric surface layer are compared with existing laboratory data to give a composite Reynolds number range spanning over three orders of magnitude. In the field experiments, a vertical rake of twenty single element hot-wires was used to measure the axial velocity, u, characteristics in the lower log layer region of the atmospheric surface layer that flows over Utah's western desert. Only data acquired under conditions of near-neutral thermal stability are analyzed. The shape of the power spectra of u as a function of distance from the wall, y, and Reynolds number is investigated, with emphasis on the appropriate scaling parameters valid across different wavenumber, k, bands. In particular, distance from the wall is found to scale the region of the u spectra around ky = 1. The presence of a k -1 slope in the spectra is also found to correlate with the Reynolds number dependence in the peak of the root mean square u profile. In addition, Reynolds number trends in the profiles of the Taylor microscales, which represent intermediate length and time scales in the boundary layer, are shown to deviate from classical scaling
International Nuclear Information System (INIS)
Welke, G.M.; Heiss, W.D.
1986-01-01
In an infinite one-dimensional quark gas it is shown that a static color force, which increases at large distance, leads to a density fluctuation in the ground state. A self-consistent mean field can only be found for an effectively attractive quark-quark interaction that increases less than linearly at large distances. For a fixed coupling constant, the clustering disappears at high quark density
Energy Technology Data Exchange (ETDEWEB)
Biswas, S. N.
1980-07-01
The application of quantum statistical mechanics to a system of particles consisting of quarks is considered. Realistic theoretical investigations have been underway to understand highly dense objects such as white dwarfs and neutron stars. The various possibilities in the case of very high densities such as 10/sup 15/ or 10/sup 16/ g/cm/sup 3/ are enumerated. The thermodynamics of a phase transition from neutron matter phase to quark matter phase is analysed. Preliminary results based on quantum chromodynamics and other phenomenological models are reported.
International Nuclear Information System (INIS)
Rho, M.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette
1983-01-01
Some features of quark degrees of freedom in nuclei are discussed in the light of recent developments in QCD. The principal aim of this talk is to propose, and give a tentative support to, the motion that one can study through nuclear matter different facets of the vacuum structure implied by quantum chromodynamics (QCD). This will be done using the recent (exciting) results obtained in particle physics, in particular lattice gauge calculations. Relevance of this aspect of problem to quark degrees of freedom as well as meson degrees of freedom in nuclei will be discussed. (orig.)
Quark Orbital Angular Momentum
Directory of Open Access Journals (Sweden)
Burkardt Matthias
2015-01-01
Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.
International Nuclear Information System (INIS)
Anon.
1995-01-01
High energy heavy ion collisions have become one of the major growth areas of modern physics. Providing common ground between particle and nuclear physics, it has produced a wave of new interest and a series of major projects to provide beams of higher energies and increasing nuclear complexity. Reflecting this interest, and despite record rainstorms, over 450 enthusiastic high energy heavy ion followers met in Monterey, California, at the 11th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions. Named Quark Matter '95, the meeting was characterized by its own flood of new results from experiments studying collisions of gold nuclei at the Brookhaven Alternating Gradient Synchrotron (AGS) and with silicon beams at the CERN SPS synchrotron, as well as preliminary results from the first run with lead beams at CERN late last year (December 1994, page 15). A striking aspect of the Conference was the growth in attendance and, in particular, the large number of young physicists who attended the meeting, underlining the vitality and appeal of this important field. The new preliminary data from CERN experiments NA44, NA49, NA52, WA97, and WA98, made available with remarkable speed following the initial lead beam run in November and December 1994, represent a significant step in the study of heavy ion collisions. Physicists have finally come close to conditions where it is possible to consider event-by-event analysis of these very complex final states. The importance of this emerging approach to relativistic heavy ion collisions was emphasized by Reinhard Stock (Frankfurt) and other speakers in a pre-conference workshop devoted to physics with the collider detectors at big new projects now in the pipeline - RHIC at Brookhaven and LHC at CERN. The study of collisions of heavy nuclei at relativistic energies is dominated by the search for the Quark-Gluon Plasma, the 'soup' of free quarks and gluons expected to have played an important role
Directory of Open Access Journals (Sweden)
Ilse Storch
2002-06-01
Full Text Available This paper explores the effects of spatial resolution on the performance and applicability of habitat models in wildlife management and conservation. A Habitat Suitability Index (HSI model for the Capercaillie (Tetrao urogallus in the Bavarian Alps, Germany, is presented. The model was exclusively built on non-spatial, small-scale variables of forest structure and without any consideration of landscape patterns. The main goal was to assess whether a HSI model developed from small-scale habitat preferences can explain differences in population abundance at larger scales. To validate the model, habitat variables and indirect sign of Capercaillie use (such as feathers or feces were mapped in six study areas based on a total of 2901 20 m radius (for habitat variables and 5 m radius sample plots (for Capercaillie sign. First, the model's representation of Capercaillie habitat preferences was assessed. Habitat selection, as expressed by Ivlev's electivity index, was closely related to HSI scores, increased from poor to excellent habitat suitability, and was consistent across all study areas. Then, habitat use was related to HSI scores at different spatial scales. Capercaillie use was best predicted from HSI scores at the small scale. Lowering the spatial resolution of the model stepwise to 36-ha, 100-ha, 400-ha, and 2000-ha areas and relating Capercaillie use to aggregated HSI scores resulted in a deterioration of fit at larger scales. Most importantly, there were pronounced differences in Capercaillie abundance at the scale of study areas, which could not be explained by the HSI model. The results illustrate that even if a habitat model correctly reflects a species' smaller scale habitat preferences, its potential to predict population abundance at larger scales may remain limited.
A measurement of the top quark's charge
Energy Technology Data Exchange (ETDEWEB)
Unalan, Zeynep Gunay [Michigan State Univ., East Lansing, MI (United States)
2007-01-01
The top quark was discovered in 1995 at the Fermilab National Accelerator Laboratory (Fermilab). One way to confirm if the observed top quark is really the top quark posited in the Standard Model (SM) is to measure its electric charge. In the Standard Model the top quark is the isospin partner of the bottom quark and is expected to have a charge of +2/3. However, an alternative 'exotic' model has been proposed with a fourth generation exotic quark that has the same characteristics, such as mass, as our observed top but with a charge of -4/3. This thesis presents the first CDF measurement of the top quark's charge via its decay products, a W boson and a bottom quark, using ~ 1 fb^{-1} of data. The data were collected by the CDF detector from proton anti-proton (p$\\bar{p}$) collisions at √s = 1.96 TeV at Fermilab. We classify events depending on the charges of the bottom quark and associated W boson and count the number of events which appear 'SM-like' or 'exotic-like' with a SM-like event decaying as t → W^{+}b and an exotic event as t → W^{-}b. We find the p-value under the Standard Model hypothesis to be 0.35 which is consistent with the Standard Model. We exclude the exotic quark hypothesis at an 81% confidence level, for which we have chosen a priori that the probability of incorrectly rejecting the SM would be 1%. The calculated Bayes Factor (BF) is 2 x Ln(BF)=8.54 which is interpreted as the data strongly favors the Standard Model over the exotic quark hypothesis.
Possibility of stable quark stars
International Nuclear Information System (INIS)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.
1976-08-01
A recent zero temperature equation of state which contains quark-partons separated from conventional baryons by a phase transition is used to investigate the stability of quark stars. The sensitivity to the input physics is also considered. The conclusions, which are found to be relatively model independent, indicate that a separately identifiable class of stable objects called quark stars does not exist
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)
Percolation transition in Yang-Mills matter at a finite number of colors.
Lottini, Stefano; Torrieri, Giorgio
2011-10-07
We examine baryonic matter at a quark chemical potential of the order of the confinement scale μ(q)∼Λ(QCD). In this regime, quarks are supposed to be confined but baryons are close to the "tightly packed limit" where they nearly overlap in configuration space. We show that this system will exhibit a percolation phase transition when varied in the number of colors N(c): at high N(c), large distance correlations at the quark level are possible even if the quarks are essentially confined. At low N(c), this does not happen. We discuss the relevance of this for dense nuclear matter, and argue that our results suggest a new "phase transition," varying N(c) at constant μ(q).
Unlocking color and flavor in superconducting strange quark matter
International Nuclear Information System (INIS)
Alford, Mark; Berges, Juergen; Rajagopal, Krishna
1999-01-01
We explore the phase diagram of strongly interacting matter with massless u and d quarks as a function of the strange quark mass m s and the chemical potential μ for baryon number. Neglecting electromagnetism, we describe the different baryonic and quark matter phases at zero temperature. For quark matter, we support our model-independent arguments with a quantitative analysis of a model which uses a four-fermion interaction abstracted from single-gluon exchange. For any finite m s , at sufficiently large μ we find quark matter in a color-flavor-locked state which leaves a global vector-like SU(2) color+L+R symmetry unbroken. As a consequence, chiral symmetry is always broken in sufficiently dense quark matter. As the density is reduced, for sufficiently large m s we observe a first-order transition from the color-flavor-locked phase to color superconducting phase analogous to that in two-flavor QCD. At this unlocking transition chiral symmetry is restored. For realistic values of m s our analysis indicates that chiral symmetry breaking may be present for all densities down to those characteristic of baryonic matter. This supports the idea that quark matter and baryonic matter may be continuously connected in nature. We map the gaps at the quark Fermi surfaces in the high density color-flavor-locked phase onto gaps at the baryon Fermi surfaces at low densities
High temperature QCD with three flavors of improved staggered quarks
International Nuclear Information System (INIS)
Bernard, C.; Burch, T.; Tar, C.E. de; Gottlieb, Steven; Gregory, Eric; Heller, U.M.; Osborn, J.; Sugar, R.L.; Toussaint, D.
2003-01-01
We present an update of our study of high temperature QCD with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad staggered quark action. Simulations are being carried out on lattices with N t = 4, 6 and 8 for the case of three degenerate quarks with masses less than or equal to the strange quark mass, m s and on lattices with N t = 6 and 8 for degenerate up and down quarks with masses in the range 0.2m s ≤ m u,d ≤ 0.6m s and the strange quark fixed near its physical value. We also report on first computations of quark number susceptibilities with the Asqtad action. These susceptibilities are of interest because they can be related to event-by-event fluctuations in heavy ion collision experiments. Use of the improved quark action leads to a substantial reduction in lattice artifacts. This can be seen already for free fermions and carries over into our results for QCD
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
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.)
Exploring the safety in numbers effect for vulnerable road users on a macroscopic scale.
Tasic, Ivana; Elvik, Rune; Brewer, Simon
2017-12-01
A "Safety in Numbers" effect for a certain group of road users is present if the number of crashes increases at a lower rate than the number of road users. The existence of this effect has been invoked to justify investments in multimodal transportation improvements in order to create more sustainable urban transportation systems by encouraging walking, biking, and transit ridership. The goal of this paper is to explore safety in numbers effect for cyclists and pedestrians in areas with different levels of access to multimodal infrastructure. Data from Chicago served to estimate the expected number of crashes on the census tract level by applying Generalized Additive Models (GAM) to capture spatial dependence in crash data. Measures of trip generation, multimodal infrastructure, network connectivity and completeness, and accessibility were used to model travel exposure in terms of activity, number of trips, trip length, travel opportunities, and conflicts. The results show that a safety in numbers effect exists on a macroscopic level for motor vehicles, pedestrians, and bicyclists. Copyright © 2017 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Deligeorges, S.
1985-01-01
After a brief recall on the classification of subatomic particles, this paper deals with quark nuggets, particle with more than three quarks, a big bag, which is called ''nuclearite''. Neutron stars, in fact, are big sacks of quarks, gigantic nuggets. Now, physicists try to calculate which type of nuggets of strange quark matter is stable, what has been the influence of quark nuggets on the primordial nucleosynthesis. At the present time, one says that if these ''nuggets'' exist, and in a large proportion, they may be candidates for the missing mass [fr
Basic features of the pion valence-quark distribution function
Energy Technology Data Exchange (ETDEWEB)
Chang, Lei [CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005 (Australia); Mezrag, Cédric; Moutarde, Hervé [Centre de Saclay, IRFU/Service de Physique Nucléaire, F-91191 Gif-sur-Yvette (France); Roberts, Craig D. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Rodríguez-Quintero, Jose [Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Huelva E-21071 (Spain); Tandy, Peter C. [Center for Nuclear Research, Department of Physics, Kent State University, Kent, OH 44242 (United States)
2014-10-07
The impulse-approximation expression used hitherto to define the pion's valence-quark distribution function is flawed because it omits contributions from the gluons which bind quarks into the pion. A corrected leading-order expression produces the model-independent result that quarks dressed via the rainbow–ladder truncation, or any practical analogue, carry all the pion's light-front momentum at a characteristic hadronic scale. Corrections to the leading contribution may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea-quarks. Working with available empirical information, we use an algebraic model to express the principal impact of both classes of corrections. This enables a realistic comparison with experiment that allows us to highlight the basic features of the pion's measurable valence-quark distribution, q{sup π}(x); namely, at a characteristic hadronic scale, q{sup π}(x)∼(1−x){sup 2} for x≳0.85; and the valence-quarks carry approximately two-thirds of the pion's light-front momentum.
Energy Technology Data Exchange (ETDEWEB)
Hinzmann, Andreas Dominik
2011-10-07
The Large Hadron Collider (LHC) at the Conseil Europeen pour la Recherche Nucleaire (CERN) allows to study the interactions of quarks and gluons in a yet unexplored energy regime. In 2010, the LHC delivered an integrated luminosity of more than 36 pb{sup -1} of proton-proton collisions at a center-of-mass energy of {radical}(s)=7 TeV. In these proton-proton collisions, the interactions of the constituent quarks and gluons produced a considerable amount of jets of particles with transverse momenta above 1 TeV. Well suited for the study of these jet processes is the Compact Muon Solenoid (CMS) experiment situated at the LHC point 5 as it can measure jets with the necessary energy and angular resolutions over a large range of transverse momentum ({proportional_to}30 GeV
quarks (quark compositeness). Models describing quarks as bound states of constituent particles may be able to explain the number of quark generations, quark masses and charges. A common signature of these models are additional contact interactions between quarks in high-momentum-transfer interactions, observable in the cross section of jet processes. Inspired by the Rutherford experiment, the scattering angle of two-jet processes (dijets) is measured to study the point-like quark and gluon scattering processes predicted by QCD. The dijet scattering angle is expressed in terms of {chi}{sub dijet} = e {sup vertical} {sup stroke} {sup y{sub 1}-y
Energy Technology Data Exchange (ETDEWEB)
Hinzmann, Andreas Dominik
2011-10-07
The Large Hadron Collider (LHC) at the Conseil Europeen pour la Recherche Nucleaire (CERN) allows to study the interactions of quarks and gluons in a yet unexplored energy regime. In 2010, the LHC delivered an integrated luminosity of more than 36 pb{sup -1} of proton-proton collisions at a center-of-mass energy of {radical}(s)=7 TeV. In these proton-proton collisions, the interactions of the constituent quarks and gluons produced a considerable amount of jets of particles with transverse momenta above 1 TeV. Well suited for the study of these jet processes is the Compact Muon Solenoid (CMS) experiment situated at the LHC point 5 as it can measure jets with the necessary energy and angular resolutions over a large range of transverse momentum ({proportional_to}30 GeV
quarks (quark compositeness). Models describing quarks as bound states of constituent particles may be able to explain the number of quark generations, quark masses and charges. A common signature of these models are additional contact interactions between quarks in high-momentum-transfer interactions, observable in the cross section of jet processes. Inspired by the Rutherford experiment, the scattering angle of two-jet processes (dijets) is measured to study the point-like quark and gluon scattering processes predicted by QCD. The dijet scattering angle is expressed in terms of {chi}{sub dijet} = e {sup vertical} {sup stroke} {sup y{sub 1}-y
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
Scale up of a luminescent solar concentrator based photomicroreactor via numbering-up
Zhao, Fang; Cambié, Dario; Janse, Jeroen; Wieland, Eric W.; Kuijpers, Koen P.L.; Hessel, Volker; Debije, Michael G.; Noël, Timothy
2018-01-01
The use of solar energy to power chemical reactions is a long-standing dream of the chemical community. Recently, visible-light-mediated photoredox catalysis has been recognized as the ideal catalytic transformation to convert solar energy into chemical bonds. However, scaling photochemical
Top quark pair production at the LHC
Energy Technology Data Exchange (ETDEWEB)
Baernreuther, Peter
2012-06-28
production in quark anti-quark annihilation channel, and the result of the double virtual corrections in the gluon fusion channel. The latter was calculated by the author in his doctoral thesis autonomously. Our results agree with already published partial results. Furthermore, the author was involved in the improvement of the double virtual corrections in the quark annihilation channel through implementation of newly developed methods. The complete NNLO results enable a reduction of the scale dependence of the production process from 15% to 4%. This allows an excellent comparison with the experimental results. Another essential component of this work, was the development and implementation of new methods for the computer-aided calculation of the production process.
Top quark pair production at the LHC
International Nuclear Information System (INIS)
Baernreuther, Peter
2012-01-01
annihilation channel, and the result of the double virtual corrections in the gluon fusion channel. The latter was calculated by the author in his doctoral thesis autonomously. Our results agree with already published partial results. Furthermore, the author was involved in the improvement of the double virtual corrections in the quark annihilation channel through implementation of newly developed methods. The complete NNLO results enable a reduction of the scale dependence of the production process from 15% to 4%. This allows an excellent comparison with the experimental results. Another essential component of this work, was the development and implementation of new methods for the computer-aided calculation of the production process.
Quark effects in nuclear physics
International Nuclear Information System (INIS)
Miller, G.A.
1983-01-01
A phenomenological approach which enables the size of quark effects in various nuclear processes is discussed. The principle of conservation of probability provides significant constraints on six quark wave functions. Using this approach, it is found that the low-energy proton-proton weak interaction can be explained in terms of W and Z boson exchanges between quarks. That the value of the asymptotic ratio of D to S state wave functions is influenced (at the 5% level) by quark effects, is another result of our approach. We have not discovered a nuclear effect that can be uniquely explained by quark-quark interactions. However it does seem that quark physics is very relevant for nuclear physics. 52 references
Top-quark pair production in a running mass scheme
Energy Technology Data Exchange (ETDEWEB)
Dowling, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik
2013-11-15
Between the Tevatron and LHC, top-quark physics is now becoming an area for precision physics. This has lead to an increase in theoretical activity to match the experimental accuracy of top anti-top production. We discuss the difficulty in properly defining the top-quark mass as measured by experiments and present results for differential distributions of top-quark pair production in a running mass scheme. The use of such a scheme shows better convergence in the perturbative expansion and improves the scale dependence as opposed to the typical on-shell scheme.
Top-quark pair production in a running mass scheme
International Nuclear Information System (INIS)
Dowling, M.; Moch, S.; Hamburg Univ.
2013-11-01
Between the Tevatron and LHC, top-quark physics is now becoming an area for precision physics. This has lead to an increase in theoretical activity to match the experimental accuracy of top anti-top production. We discuss the difficulty in properly defining the top-quark mass as measured by experiments and present results for differential distributions of top-quark pair production in a running mass scheme. The use of such a scheme shows better convergence in the perturbative expansion and improves the scale dependence as opposed to the typical on-shell scheme.
The breaking of flavor democracy in the quark sector
Fritzsch, Harald; Xing, Zhi-Zhong; Zhang, Di
2017-09-01
The democracy of quark flavors is a well-motivated flavor symmetry, but it must be properly broken in order to explain the observed quark mass spectrum and flavor mixing pattern. We reconstruct the texture of flavor democracy breaking and evaluate its strength in a novel way, by assuming a parallelism between the Q=+2/3 and Q=-1/3 quark sectors and using a nontrivial parametrization of the flavor mixing matrix. Some phenomenological implications of such democratic quark mass matrices, including their variations in the hierarchy basis and their evolution from the electroweak scale to a super-high energy scale, are also discussed. Supported by National Natural Science Foundation of China (11375207) and National Basic Research Program of China (2013CB834300)
A large-scale survey of genetic copy number variations among Han Chinese residing in Taiwan
Directory of Open Access Journals (Sweden)
Wu Jer-Yuarn
2008-12-01
Full Text Available Abstract Background Copy number variations (CNVs have recently been recognized as important structural variations in the human genome. CNVs can affect gene expression and thus may contribute to phenotypic differences. The copy number inferring tool (CNIT is an effective hidden Markov model-based algorithm for estimating allele-specific copy number and predicting chromosomal alterations from single nucleotide polymorphism microarrays. The CNIT algorithm, which was constructed using data from 270 HapMap multi-ethnic individuals, was applied to identify CNVs from 300 unrelated Han Chinese individuals in Taiwan. Results Using stringent selection criteria, 230 regions with variable copy numbers were identified in the Han Chinese population; 133 (57.83% had been reported previously, 64 displayed greater than 1% CNV allele frequency. The average size of the CNV regions was 322 kb (ranging from 1.48 kb to 5.68 Mb and covered a total of 2.47% of the human genome. A total of 196 of the CNV regions were simple deletions and 27 were simple amplifications. There were 449 genes and 5 microRNAs within these CNV regions; some of these genes are known to be associated with diseases. Conclusion The identified CNVs are characteristic of the Han Chinese population and should be considered when genetic studies are conducted. The CNV distribution in the human genome is still poorly characterized, and there is much diversity among different ethnic populations.
New signals for vector-like down-type quark in U(1) of E_6
Das, Kasinath; Li, Tianjun; Nandi, S.; Rai, Santosh Kumar
2018-01-01
We consider the pair production of vector-like down-type quarks in an E_6 motivated model, where each of the produced down-type vector-like quark decays into an ordinary Standard Model light quark and a singlet scalar. Both the vector-like quark and the singlet scalar appear naturally in the E_6 model with masses at the TeV scale with a favorable choice of symmetry breaking pattern. We focus on the non-standard decay of the vector-like quark and the new scalar which decays to two photons or two gluons. We analyze the signal for the vector-like quark production in the 2γ +≥ 2j channel and show how the scalar and vector-like quark masses can be determined at the Large Hadron Collider.
Hadron structure in a simple model of quark/nuclear matter
International Nuclear Information System (INIS)
Horowitz, C.J.; Moniz, E.J.; Negele, J.W.
1985-01-01
We study a simple model for one-dimensional hadron matter with many of the essential features needed for examining the transition from nuclear to quark matter and the limitations of models based upon hadron rather than quark degrees of freedom. The dynamics are generated entirely by the quark confining force and exchange symmetry. Using Monte Carlo techniques, the ground-state energy, single-quark momentum distribution, and quark correlation function are calculated for uniform matter as a function of density. The quark confinement scale in the medium increases substantially with increasing density. This change is evident in the correlation function and momentum distribution, in qualitative agreement with the changes observed in deep-inelastic lepton scattering. Nevertheless, the ground-state energy is smooth throughout the transition to quark matter and is described remarkably well by an effective hadron theory based on a phenomenological hadron-hadron potential
More about unphysical zeroes in quark mass matrices
Energy Technology Data Exchange (ETDEWEB)
Emmanuel-Costa, David, E-mail: david.costa@tecnico.ulisboa.pt [Departamento de Física and Centro de Física Teórica de Partículas - CFTP, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); González Felipe, Ricardo, E-mail: ricardo.felipe@tecnico.ulisboa.pt [Departamento de Física and Centro de Física Teórica de Partículas - CFTP, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa (Portugal); ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Rua Conselheiro Emídio Navarro, 1959-007 Lisboa (Portugal)
2017-01-10
We look for all weak bases that lead to texture zeroes in the quark mass matrices and contain a minimal number of parameters in the framework of the standard model. Since there are ten physical observables, namely, six nonvanishing quark masses, three mixing angles and one CP phase, the maximum number of texture zeroes in both quark sectors is altogether nine. The nine zero entries can only be distributed between the up- and down-quark sectors in matrix pairs with six and three texture zeroes or five and four texture zeroes. In the weak basis where a quark mass matrix is nonsingular and has six zeroes in one sector, we find that there are 54 matrices with three zeroes in the other sector, obtainable through right-handed weak basis transformations. It is also found that all pairs composed of a nonsingular matrix with five zeroes and a nonsingular and nondecoupled matrix with four zeroes simply correspond to a weak basis choice. Without any further assumptions, none of these pairs of up- and down-quark mass matrices has physical content. It is shown that all non-weak-basis pairs of quark mass matrices that contain nine zeroes are not compatible with current experimental data. The particular case of the so-called nearest-neighbour-interaction pattern is also discussed.
HUNTING THE QUARK GLUON PLASMA.
Energy Technology Data Exchange (ETDEWEB)
LUDLAM, T.; ARONSON, S.
2005-04-11
The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been accessible only for high-energy physics experiments with collisions of ''elementary'' particles such as protons and electrons. It is at these high energies that the predictions of quantum chromodynamics (QCD), the fundamental theory that describes the role of quarks and gluons in nuclear matter, come into play, and new phenomena are sought that may illuminate our view of the basic structure of matter on the sub-atomic scale, with important implications for the origins of matter on the cosmic scale. The RHIC experiments have recorded data from collisions of gold nuclei at the highest energies ever achieved in man-made particle accelerators. These collisions, of which hundreds of millions have now been examined, result in final states of unprecedented complexity, with thousands of produced particles radiating from the nuclear collision. All four of the RHIC experiments have moved quickly to analyze these data, and have begun to understand the phenomena that unfold from the moment of collision as these particles are produced. In order to provide benchmarks of simpler interactions against which to compare the gold-gold collisions, the experiments have gathered comparable samples of data from collisions of a very light nucleus (deuterium) with gold nuclei, as well as proton-proton collisions, all with identical beam energies and experimental apparatus. The early measurements have revealed compelling evidence for the existence of a new form of nuclear
HUNTING THE QUARK GLUON PLASMA
International Nuclear Information System (INIS)
LUDLAM, T.; ARONSON, S.
2005-01-01
The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been accessible only for high-energy physics experiments with collisions of ''elementary'' particles such as protons and electrons. It is at these high energies that the predictions of quantum chromodynamics (QCD), the fundamental theory that describes the role of quarks and gluons in nuclear matter, come into play, and new phenomena are sought that may illuminate our view of the basic structure of matter on the sub-atomic scale, with important implications for the origins of matter on the cosmic scale. The RHIC experiments have recorded data from collisions of gold nuclei at the highest energies ever achieved in man-made particle accelerators. These collisions, of which hundreds of millions have now been examined, result in final states of unprecedented complexity, with thousands of produced particles radiating from the nuclear collision. All four of the RHIC experiments have moved quickly to analyze these data, and have begun to understand the phenomena that unfold from the moment of collision as these particles are produced. In order to provide benchmarks of simpler interactions against which to compare the gold-gold collisions, the experiments have gathered comparable samples of data from collisions of a very light nucleus (deuterium) with gold nuclei, as well as proton-proton collisions, all with identical beam energies and experimental apparatus. The early measurements have revealed compelling evidence for the existence of a new form of nuclear matter at extremely high
Search for vector-like quarks and excited quarks at CMS
Rauco, Giorgia
2017-01-01
We present the results of the latest searches for new hypothetical heavy quarks using proton-proton collisions data collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV. Vector-like quarks are postulated to solve the hierarchy problem and stabilize the Higgs mass and they are not constrained by the Higgs discovery and electroweak measurements, as for the case of a fourth generation of fermions. They can either be produced singly or pair-wise and their decays result in a variety of final states, containing massive standard model quarks and bosons (Z, W, H). Being these new particles expected to be appearing at the TeV scale, they give rise to boosted topologies, in which jet substructures techniques play a fundamental role. An alternative type of heavy quark resonance are the excited quarks, which are predicted by the compositeness model, being their evidence a clear signature of the composite structure of the ordinary matter. Their decay leads to the corresponding ordinary qua...
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.)
Study of dibaryon states containing three different types of quarks
International Nuclear Information System (INIS)
Leandri, J.; Silvestre-Brac, B.
1997-01-01
Previously we have shown, in a simple chromomagnetic model, that including heavy quarks in the dibaryon sector can lead to favorable configurations for stability against decay into two baryons. In this study we investigate a reduced set of favorable candidates that have emerged from our previous works. We use a non-relativistic quark model with quarks interacting through a QCD-inspired potential, which has been tested previously in meson and baryon spectroscopy. A variational procedure is performed using a great number of Gaussian functions containing all the possibilities for colour, isospin, and spin components. (author)
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
Nucleon quark distributions in a covariant quark-diquark model
Energy Technology Data Exchange (ETDEWEB)
Cloet, I.C. [Special Research Centre for the Subatomic Structure of Matter and Department of Physics and Mathematical Physics, University of Adelaide, SA 5005 (Australia) and Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)]. E-mail: icloet@physics.adelaide.edu.au; Bentz, W. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan)]. E-mail: bentz@keyaki.cc.u-tokai.ac.jp; Thomas, A.W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)]. E-mail: awthomas@jlab.org
2005-08-18
Spin-dependent and spin-independent quark light-cone momentum distributions and structure functions are calculated for the nucleon. We utilize a modified Nambu-Jona-Lasinio model in which confinement is simulated by eliminating unphysical thresholds for nucleon decay into quarks. The nucleon bound state is obtained by solving the Faddeev equation in the quark-diquark approximation, where both scalar and axial-vector diquark channels are included. We find excellent agreement between our model results and empirical data.
Prediction of new Quarks, Generations & low Mass Quarks
Lach, Theodore
2003-04-01
The CBM (model) of the nucleus has resulted in the prediction of two new quarks, an "up" quark of mass 237.31 MeV/c2 and a "dn" quark of mass 42.392 MeV/c2. These two new predicted quarks helped to determine that the masses of the quarks and leptons are all related by a geometric progression relationship. The mass of each quark or lepton is just the "geometric mean" of two related elementary particles, either in the same generation or in the same family. This numerology predicts the following masses for the electron family: 0.511000 (electron), 7.74 (predicted), 117.3, 1778.4 (tau), 26950.1 MeV. The geometric ratio of this progression is 15.154 (e to the power e). The mass of the tau in this theory agrees very well with accepted values. This theory suggests that all the "dn like" quarks have a mass of just 10X multiples of 4.24 MeV (the mass of the "d" quark). The first 3 "up like" quark masses are 38, 237.31 and 1500 MeV. This theory also predicts a new heavy generation with a lepton mass of 27 GeV, a "dn like" quark of 42.4 GeV, and an "up like" quark of 65 GeV. Significant evidence already exists for the existence of these new quarks, and lepton. Ref. Masses of the Sub-Nuclear Particles, nucl-th/ 0008026, @ http://xxx.lanl.gov. Infinite Energy, Vol 5, issue 30.
1990-01-01
This volume contains 14 review articles on the theory and phenomenology of the creation and diagnosis of quark-gluon plasma. They are written by active investigators of in the various research topics, which range from the QCD foundation through transport theory and thermalization models to the examination of possible signatures. The monograph should be useful not only to the experienced researchers in the subject but also to newcomers.
Wood, Barry
2018-01-01
The value of Tyler Volk’s Quarks to Culture is evident when the book is placed against popular histories of the universe, dozens of which have provided evidence for an immense cosmic past. But such histories are often anecdotal, like early British histories of the kings of England. Unlike these works, Volk artfully presents the case for structural continuity and systematic creativity across 13.8 billion years of cosmic history.
International Nuclear Information System (INIS)
Paschos, E.A.
1976-08-01
The quark parton model describes the inclusive electro- and neutrino production data if a clear distinction is made between reactions which take place at high and at low energies. For the low energy region the classical view of six structure functions of the proton is still adequate. For the high energy region models can be constructed which are consistent with the experimental data. (BJ) [de
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.
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.)
Nayak, Tapan; Sarkar, Sourav
2014-01-01
At extremely high temperatures and densities, protons and neutrons may dissolve into a "soup" of quarks and gluons, called the Quark-Gluon Plasma (QGP). For a few microseconds, shortly after the Big Bang, the Universe was filled with the QGP matter. The search and study of Quark-Gluon Plasma (QGP) is one of the most fundamental research topics of our times. The QGP matter has been probed by colliding heavy ions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, New York and the Large Hadron Collider at CERN, Geneva. By colliding heavy-ions at a speed close to that of light, scientists aim to obtain - albeit over a tiny volume of the size of a nucleus and for an infinitesimally short instant - a QGP state. This QGP state can be observed by dedicated experiments, as it reverts to hadronic matter through expansion and cooling. This volume presents some of the current theoretical and experimental understandings in the field of QGP.
Fields, symmetries, and quarks
International Nuclear Information System (INIS)
Mosel, U.
1989-01-01
'Fields, symmetries, and quarks' covers elements of quantum field theory, symmetries, gauge field theories and phenomenological descriptions of hadrons, with special emphasis on topics relevant to nuclear physics. It is aimed at nuclear physicists in general and at scientists who need a working knowledge of field theory, symmetry principles of elementary particles and their interactions and the quark structure of hadrons. The book starts out with an elementary introduction into classical field theory and its quantization. As gauge field theories require a working knowledge of global symmetries in field theories this topic is then discussed in detail. The following part is concerned with the general structure of gauge field theories and contains a thorough discussion of the still less widely known features of Non-Abelian gauge field theories. Quantum Chromodynamics (QCD), which is important for the understanding of hadronic matter, is discussed in the next section together with the quark compositions of hadrons. The last two chapters give a detailed discussion of phenomenological bag-models. The MIT bag is discussed, so that all theoretical calculations can be followed step by step. Since in all other bag-models the calculational methods and steps are essentially identical, this chapter should enable the reader to actually perform such calculations unaided. A last chapter finally discusses the topological bag-models which have become quite popular over the last few years. (orig.)
Transversity quark distributions in a covariant quark-diquark model
Energy Technology Data Exchange (ETDEWEB)
Cloet, I.C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439-4843 (United States)], E-mail: icloet@anl.gov; Bentz, W. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan)], E-mail: bentz@keyaki.cc.u-tokai.ac.jp; Thomas, A.W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); College of William and Mary, Williamsburg, VA 23187 (United States)], E-mail: awthomas@jlab.org
2008-01-17
Transversity quark light-cone momentum distributions are calculated for the nucleon. We utilize a modified Nambu-Jona-Lasinio model in which confinement is simulated by eliminating unphysical thresholds for nucleon decay into quarks. The nucleon bound state is obtained by solving the relativistic Faddeev equation in the quark-diquark approximation, where both scalar and axial-vector diquark channels are included. Particular attention is paid to comparing our results with the recent experimental extraction of the transversity distributions by Anselmino et al. We also compare our transversity results with earlier spin-independent and helicity quark distributions calculated in the same approach.
Quark core stars, quark stars and strange stars
International Nuclear Information System (INIS)
Grassi, F.
1988-01-01
A recent one flavor quark matter equation of state is generalized to several flavors. It is shown that quarks undergo a first order phase transition. In addition, this equation of state depends on just one parameter in the two flavor case, two parameters in the three flavor case, and these parameters are constrained by phenomenology. This equation of state is then applied to the hadron-quark transition in neutron stars and the determination of quark star stability, the investigation of strange matter stability and possible strange star existence. 43 refs., 6 figs
Top quark pair production and top quark properties at CDF
Energy Technology Data Exchange (ETDEWEB)
Moon, Chang-Seong [INFN, Pisa
2016-06-02
We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.
Baryon- and lepton-number non-conserving processes and intermediate mass scales
International Nuclear Information System (INIS)
Nieves, J.F.
1981-01-01
An analysis of the possible mechanisms to mediate various baryon- and lepton-number non-conserving processes is presented. Processes considered include the Δ(B+L) = 0 proton decay, ΔB = 2 neutron-antineutron oscillations and neutrino Majorana masses. Among our results we find that, in the absence of elementary scalars and exotic fermions, all the renormalizable interactions of vector bosons and ordinary fermions conserve B-L. Therefore, the observation of Δ(B-L) not equal 0 processes would imply the existence of elementary scalars and/or exotic fermions. (orig.)
A Study of charm quark production in beauty quark decays with the OPAL detector at LEP
Waller, David
2003-01-01
The production of charm quarks in beauty quark decays has been studied with the OPAL detector at the Large Electron Positron collider near Geneva, Switzerland. The branching ratio Br(b -1 DDX) has been measured using hadronic zo decays collected between 1993 and 1995. Here b refers to the admixture of weakly decaying hadrons containing ab quark that are produced in electron-positron annihilations at a centre of mass energy equal to the mass of the zo boson. The impact parameter significance of tracks in tagged b-jets is used to differentiate b -1 DDX decays from other decays. The result is Br(b -1 DDX) = (10.0 ± 3.2(stat.)~~:~(syst. det.)~~~04 (syst. phys.))%. where syst. det. is the systematic uncertainty due to the modelling of the detector, and syst. phys. is the systematic uncertainty due to the modelling of the underlying particle physics. Using this result, the average number of charm and anti-charm quarks produced in a beauty quark decay, nc, is found to be l.12~8:i6- Ill
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
Quark solitons as constituents of hadrons
International Nuclear Information System (INIS)
Ellis, J.; Frishman, Y.; Hanany, A.; Karlinev, M.
1992-01-01
We exhibit static solutions of multi-flavour QCD in two dimensions that have the quantum numbers of baryons and mesons, constructed out of quark and anti-quark solitons. In isolation the latter solitons have infinite energy, corresponding to the presence of a string carrying the non-singlet colour flux off to spatial infinity. When N c solitons of this type are combined, a static, finite-energy, colour singlet solution is formed, corresponding to a baryon. Similarly, static meson solutions are formed out of a soliton and an anti-soliton of different flavours. The stability of the mesons against annihilation is ensured by flavour conservation. The static solutions exist only when the fundamental fields of the bosonized lagrangian belong to U(N c xN f ) rather than to SU(N c )xU(N f ). Discussion of flavour-symmetry breaking requires a careful treatment of the normal-ordering ambiguity. Our results can be viewed as a derivation of the constituent quark model in QCD 2 , allowing a detailed study of constituent mass generation and of the heavy-quark symmetry. (orig.)
Roth, J. R.
1976-01-01
Parametric variation of independent variables which may affect the characteristics of bumpy torus plasma have identified those which have a significant effect on the plasma current, ion kinetic temperature, and plasma number density, and those which do not. Empirical power law correlations of the plasma current, and the ion kinetic temperature and number density were obtained as functions of potential applied to the midplane electrode rings, the background neutral gas pressure, and the magnetic field strength. Additional parameters studied included the type of gas, the polarity of the midplane electrode rings, the mode of plasma operation, and the method of measuring the plasma number density. No significant departures from the scaling laws appear to occur at the highest ion kinetic temperatures or number densities obtained to date.
Nonequilibrium quark production in the expanding QCD plasma
Tanji, Naoto; Berges, Jürgen
2018-02-01
We perform real-time lattice simulations of nonequilibrium quark production in the longitudinally expanding QCD plasma. Starting from a highly occupied gluonic state with vacuum quark sector, we extract the time evolution of quark and gluon number densities per unit transverse area and rapidity. The total quark number shows after an initial rapid increase an almost linear growth with time. Remarkably, this growth rate appears to be consistent with a simple kinetic theory estimate involving only two-to-two scattering processes in small-angle approximation. This extends previous findings about the role of two-to-two scatterings for purely gluonic dynamics in accordance with the early stages of the bottom-up thermalization scenario.
A quark matter contribution to the cosmic ray spectrum
International Nuclear Information System (INIS)
Lawson, K.
2013-01-01
I will describe a possible dark matter model in which the dark matter is composed of heavy nuggets of standard model quarks and antiquarks bound in a high density phase of QCD. If objects of this type are formed early in the universe's history they may provide the observed dark matter content. In this scenario the nuggets are dark not because of their fundamentally weak interactions but because of the incredibly small number density required to explain the observed mass density of the dark matter. The correspondingly small flux of these objects through the earth renders them invisible to conventional high sensitivity dark matter searches intended to detect weakly interacting particles with a flux many orders of magnitude larger. Instead the greatest search potential for dark matter models of this form may come from the largest scale cosmic ray detectors. I will briefly describe the properties of quark nugget dark matter and then use these properties in order to predict the signal they would produce in a variety of cosmic ray detectors. (authors)
Static quark-antiquark potential
International Nuclear Information System (INIS)
Deo, B.B.; Barik, B.K.
1983-01-01
A heavy-quark--antiquark potential is suggested which connects asymptotic freedom and quark confinement in a unified manner by formal methods of field theory using some plausible assumptions. The potential has only one additional adjustable parameter B which is proportional to (M/sub q//m/sub q/), where M/sub q/ and m/sub q/ are the constituent and current quark masses, respectively
Infrared slavery and quark confinement
Alabiso, C
1976-01-01
The question is considered of whether the so-called infrared slavery mechanism as, e.g., being manifest in non-Abelian gauge theories, necessarily confines quarks. Making a specific ansatz for the long- range forces, the Schwinger-Dyson equation is solved for the quark Green function. Besides having a confining solution, it appears that quarks may by-pass the long-range forces and be produced. (20 refs).
Infrared slavery and quark confinement
International Nuclear Information System (INIS)
Alabiso, C.; Schierholz, G.
1976-01-01
The question of whether the so-called infrared slavery mechanism as, e.g., being manifest in non-Abelian gauge theories, necessarily confines quarks is posed. Making a specific ansatz for the long-range forces, the Schwinger-Dyson equation is solved for the quark Green function. Besides having a confining solution, it appears that quarks may by-pass the long-range forces and be produced. (Auth.)
Exotic Signals of Vectorlike Quarks
Energy Technology Data Exchange (ETDEWEB)
Dobrescu, Bogdan A. [Fermilab; Yu, Felix [U. Mainz, PRISMA
2016-12-06
Vectorlike fermions are an important target for hadron collider searches. We show that the vectorlike quarks may predominantly decay via higher-dimensional operators into a quark plus a couple of other Standard Model fermions. Pair production of vectorlike quarks of charge 2/3 at the LHC would then lead to a variety of possible final states, including $t\\bar t + 4\\tau$, $t\\bar b\
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
Quark matter or new particles?
Michel, F. Curtis
1988-01-01
It has been argued that compression of nuclear matter to somewhat higher densities may lead to the formation of stable quark matter. A plausible alternative, which leads to radically new astrophysical scenarios, is that the stability of quark matter simply represents the stability of new particles compounded of quarks. A specific example is the SU(3)-symmetric version of the alpha particle, composed of spin-zero pairs of each of the baryon octet (an 'octet' particle).
Datta, D P
2003-01-01
We show that the generic 1/f spectrum problem acquires a natural explanation in a class of scale free solutions to the ordinary differential equations. We prove the existence and uniqueness of this class of solutions and show how this leads to a nonstandard, fuzzy extension of the ordinary framework of calculus, and hence, that of the classical dynamics and quantum mechanics. The exceptional role of the golden mean irrational number is also explained.
International Nuclear Information System (INIS)
Datta, Dhurjati Prasad
2003-01-01
We show that the generic 1/f spectrum problem acquires a natural explanation in a class of scale free solutions to the ordinary differential equations. We prove the existence and uniqueness of this class of solutions and show how this leads to a nonstandard, fuzzy extension of the ordinary framework of calculus, and hence, that of the classical dynamics and quantum mechanics. The exceptional role of the golden mean irrational number is also explained
International Nuclear Information System (INIS)
Zouzou, S.
1986-01-01
In the framework of simple non-relativistic potential models, we examine the system consisting of two quarks and two antiquarks with equal or unequal masses. We search for possible bound states below the threshold for the spontaneous dissociation into two mesons. We solve the four body problem by empirical or systematic variational methods and we include the virtual meson-meson components of the wave function. With standard two-body potentials, there is no proliferation of multiquarks. With unequal quark masses, we obtain however exotic (anti Qanti Qqq) bound states with a baryonic antidiquark-quark-quark structure very analogous to the heavy flavoured (Q'qq) baryons. (orig.)
Rzhetsky, A; Gomez, S M
2001-10-01
Current growth in the field of genomics has provided a number of exciting approaches to the modeling of evolutionary mechanisms within the genome. Separately, dynamical and statistical analyses of networks such as the World Wide Web and the social interactions existing between humans have shown that these networks can exhibit common fractal properties-including the property of being scale-free. This work attempts to bridge these two fields and demonstrate that the fractal properties of molecular networks are linked to the fractal properties of their underlying genomes. We suggest a stochastic model capable of describing the evolutionary growth of metabolic or signal-transduction networks. This model generates networks that share important statistical properties (so-called scale-free behavior) with real molecular networks. In particular, the frequency of vertices connected to exactly k other vertices follows a power-law distribution. The shape of this distribution remains invariant to changes in network scale: a small subgraph has the same distribution as the complete graph from which it is derived. Furthermore, the model correctly predicts that the frequencies of distinct DNA and protein domains also follow a power-law distribution. Finally, the model leads to a simple equation linking the total number of different DNA and protein domains in a genome with both the total number of genes and the overall network topology. MatLab (MathWorks, Inc.) programs described in this manuscript are available on request from the authors. ar345@columbia.edu.
Search for excited quarks in ep collisions at HERA
International Nuclear Information System (INIS)
Aaron, F.D.; Alimujiang, K.
2009-03-01
A search for excited quarks is performed using the full e ± p data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb -1 . The electroweak decays of excited quarks q * →qγ, q * →qZ and q * →qW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q * production cross sections and on the ratio f/Λ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches. (orig.)
Search for excited quarks in ep collisions at HERA
Energy Technology Data Exchange (ETDEWEB)
Aaron, F.D. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Alimujiang, K. [DESY, Hamburg (DE)] (and others)
2009-03-15
A search for excited quarks is performed using the full e{sup {+-}}p data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb{sup -1}. The electroweak decays of excited quarks q{sup *}{yields}q{gamma}, q{sup *}{yields}qZ and q{sup *}{yields}qW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q{sup *} production cross sections and on the ratio f/{lambda} of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches. (orig.)
Differences between quark and gluon jets at LEP1
Boutemeur, Madjid
1997-01-01
A report is ven here on the differences between quark and gluon initiated jets as measured in LEPl. Various measurements, agree qualitatively on the differences between quark and gluon jets. However a direct quantitative comparison among the measurements as well as comparisons between the measurements and analytical calculations are difficult. This is due to the dependence of the results on the selected event topologies and used jet finding algorithms. Topology dependence of the charged particle multiplicity in quark and gluon jets is studied by ALEPH and transverse momentum-like scales are proposed to account for it. OPAL produced the first quantitative test of QCD analytic prediction for the ratio of the mean particle multiplicity between gluon and quark jets valid, at least, for 39 GeV jets.
Hadron production at RHIC: recombination of quarks
Energy Technology Data Exchange (ETDEWEB)
Fries, Rainer J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
2005-01-01
We discuss quark recombination applied to the hadronization of a quark gluon plasma. It has been shown that the quark recombination model can explain essential features of hadron production measured in high energy heavy ion collisions.
Cold quark matter in compact stars
Energy Technology Data Exchange (ETDEWEB)
Franzon, B.; Fogaca, D. A.; Navarra, F. S. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)
2013-03-25
We used an equation of state for the cold quark matter to the study of properties of quark stars. We also discuss the absolute stability of quark matter and compute the mass-radius relation for self-bound stars.
Models of quark bags and their consequences
International Nuclear Information System (INIS)
Bogolubov, P.N.
1977-01-01
The development of the first Dubna Quark Bag and the results obtained in this way are considered. The idea of the first Dubna Quark Bag is as follows: baryons are constructed of three quarks measons are constructed of two quarks, and each quark is interpreted as the Dirac particle which moves in a scalar square well. The so-called quasiindependent quark model is considered too. It is a simple quark model based on an analogy with the shell model for nuclei. The quarks are considered as moving in an arbitrary radially-symmetric field, and their one-particle wave function satisfies the usual Dirac equation. Such quark model can give at least the same results as the relativistic bag model. A possibility exists to improve the results of the relativistic quark model with the oscillator interaction between quarks. The results of the MIT-Bag model and the quasiindependent quark model coincide
A gentilionic approach to quark colours
International Nuclear Information System (INIS)
Cattani, M.S.D.; Fernandes, N.C.
1984-01-01
An extended form of Noether's theorem enable us to identify the colour quantum number with the eigenvalue of the invariant of the algebra of S sup((3)). In the gentilionic approach, the composition of the S sup((3)) colour with the symmetric quark model seems to constitute an exact symmetry of Nature. It is also argued some general properties and the universality of Gentile statistics. (Author) [pt
A gentilion hypothesis for quark colours
International Nuclear Information System (INIS)
Cattani, M.S.D.; Fernandes, N.C.
1984-01-01
Extendind the Noether's theorem it is possible to identify the colour quantum numbers with the eigenvalue of a S sup((3)) algebra invariant. In the gentilion approximation, the composition of the coloured S sup((3)) with the symmetric quark model seems to constitute in an exact symmetry of the nature. Some general properties related with the observationality in Quantum Mechanics are also approached and the Gentile statistical universality is asserted. (L.C.) [pt
Quark and Gluon Relaxation in Quark-Gluon Plasmas
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.
The discovery of the top quark
International Nuclear Information System (INIS)
Sinervo, P.K.
1995-12-01
The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the Τ resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark
The Discovery of the Top Quark
Sinervo, P.K.
1995-12-01
The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.
Energy Technology Data Exchange (ETDEWEB)
Otterlund, Ingvar; Ruuskanen, Vesa
1993-12-15
In his welcome address to the 10th International Conference on Ultra- Relativistic Nucleus-Nucleus Collisions (Quark Matter '93), held in Borlange, Sweden, from 20-24 June, Hans-Ake Gustafsson was puzzled why this year's conference was billed as the tenth in the series. He had tried to count but could only find eight forerunners - Bielefeld (1982), Brookhaven (1983), Helsinki (1984), Asilomar (1986), Nordkirchen (1987), Lenox (1988), Menton (1990), Gatlinburg (1991), making this year's meeting at Borlange the ninth. The answer was given by Helmut Satz in his introductory talk, pointing out that at the time of the Bielefeld meeting, a few conferences dealing with similar topics had already been held. The Bielefeld organizers thus did not consider their conference the first. Whatever its pedigree, the Borlange meeting covered particle production in highly excited and compressed nuclear matter, fluctuations and correlations, quark phenomena (quantum chromodynamics - QCD) in nuclear collisions, probes and signatures of Quark-Gluon Plasma (QGP), future collider experiments and instrumentation. The theoretical talks were split between the fundamental properties of the hot and dense matter at or near equilibrium, and the interface between theory and experiment. The phenomenological modelling of heavy ion collisions seems to reproduce at least all the main features of the data with hadrons, resonances and strings as the degrees of freedom. However secondary interactions among the produced hadrons or strings need to be added. Hydrodynamic calculations lead to results which reproduce the main features of the collisions. With increasing collision energy, the parton degrees of freedom become more important. Klaus Geiger described an ambitious scheme treating the whole nucleus-nucleus collision in terms of a kinetic parton (quark/gluon) cascade. The initial parton distribution at the beginning of the collision is determined from the quark-gluon nuclear structure and the
International Nuclear Information System (INIS)
Otterlund, Ingvar; Ruuskanen, Vesa
1993-01-01
In his welcome address to the 10th International Conference on Ultra- Relativistic Nucleus-Nucleus Collisions (Quark Matter '93), held in Borlange, Sweden, from 20-24 June, Hans-Ake Gustafsson was puzzled why this year's conference was billed as the tenth in the series. He had tried to count but could only find eight forerunners - Bielefeld (1982), Brookhaven (1983), Helsinki (1984), Asilomar (1986), Nordkirchen (1987), Lenox (1988), Menton (1990), Gatlinburg (1991), making this year's meeting at Borlange the ninth. The answer was given by Helmut Satz in his introductory talk, pointing out that at the time of the Bielefeld meeting, a few conferences dealing with similar topics had already been held. The Bielefeld organizers thus did not consider their conference the first. Whatever its pedigree, the Borlange meeting covered particle production in highly excited and compressed nuclear matter, fluctuations and correlations, quark phenomena (quantum chromodynamics - QCD) in nuclear collisions, probes and signatures of Quark-Gluon Plasma (QGP), future collider experiments and instrumentation. The theoretical talks were split between the fundamental properties of the hot and dense matter at or near equilibrium, and the interface between theory and experiment. The phenomenological modelling of heavy ion collisions seems to reproduce at least all the main features of the data with hadrons, resonances and strings as the degrees of freedom. However secondary interactions among the produced hadrons or strings need to be added. Hydrodynamic calculations lead to results which reproduce the main features of the collisions. With increasing collision energy, the parton degrees of freedom become more important. Klaus Geiger described an ambitious scheme treating the whole nucleus-nucleus collision in terms of a kinetic parton (quark/gluon) cascade. The initial parton distribution at the beginning of the collision is determined from the quark-gluon nuclear structure
Hot nuclear matter in the modified quark-meson coupling model with quark-quark correlations
International Nuclear Information System (INIS)
Zakout, I.; Jaqaman, H.R.
2000-01-01
Short-range quark-quark correlations in hot nuclear matter are examined within the modified quark-meson coupling (MQMC) model by adding repulsive scalar and vector quark-quark interactions. Without these correlations, the bag radius increases with the baryon density. However, when the correlations are introduced the bag size shrinks as the bags overlap. Also as the strength of the scalar quark-quark correlation is increased, the decrease of the effective nucleon mass M* N with the baryonic density is slowed down and tends to saturate at high densities. Within this model we study the phase transition from the baryon-meson phase to the quark-gluon plasma (QGP) phase with the latter modelled as an ideal gas of quarks and gluons inside a bag. Two models for the QGP bag parameter are considered. In one case, the bag is taken to be medium-independent and the phase transition from the hadron phase to QGP is found to occur at five to eight times ordinary nuclear matter density for temperatures less than 60 MeV. For lower densities, the transition takes place at a higher temperature, reaching up to 130 MeV at zero density. In the second case, the QGP bag parameter is considered to be medium-dependent as in the MQMC model for the hadronic phase. In this case, it is found that the phase transition occurs at much lower densities. (author)
Kurkela, Aleksi
2016-07-20
We generalize the state-of-the-art perturbative Equation of State of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to order g^5 in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated using a dimensionally reduced effective theory, while the soft non-zero modes are resummed using the Hard Thermal Loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium.
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.
On the distribution of quarks in nuclei
International Nuclear Information System (INIS)
Baldin, A.M.; Panebrattsev, V.S.; Stavinskij, V.S.
1984-01-01
On the basis of the data on cumulative proton, deuteron and nuclear fragment production in hadr on-nucleon reactions and deep inelastic muon-nucleon scattering quark distributions in light, intemediate and heavy nuclei have been investigated. Conditions of limiting fragmentation of hadrons and nuclei in the studied processes have been investigated to obtain quark-parton structure functions (Gs 2 ) of the studied hadrons or nuclei. Invariant differential cross sections of π + , π - , K + meson production on aluminium, deuterium and lead nuclei and their dependence on scale variable at the transverse momentum value Psub(T) approximately 0 have been obtained. Properties of structure functions G 2 and behaviour of different nuclei differential cross sections of limiting fragmentation have been investigated. It is concluded that considered regularities testify to the presence of multiquark states in nuclei, different by its structure from nUcleons
On the limits of application of the nolocal quark model
International Nuclear Information System (INIS)
Efimov, G.V.; Ivanov, M.A.; Novitsyn, E.A.; Ryabtsev, A.D.
1983-01-01
The possibility of application of the nolocal quark model (NQM) to the physics of mesons, containin charmed quarks, is considered. A method for description of states with identical quantum numbers is suggested. I' order to distinguish between such states different quark currents are introduced with additional condition of ''o thogonality'' implied. The latter allows one to neglect nondiagonal off-shell matrix elements in compositeness conditi ' for coupling constants. In the framework of NQM with ditional assumptions mentioned several decay widths of vector charmonium states have been computed, namely lepton c widths of J/psi(3100), psi'(3685) and psi(3770) an the decay width into charmed D-mesons psi(3770) → D nti D. It is shown that the two-parametric freedom of the m del is not sufficient to fit the experimental data. It is co'cluded that the revision of basic concepts of NQM is nec ssary in physics of mesons containing c-quarks
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)
Quarks, gluons, colour: facts or fiction?
International Nuclear Information System (INIS)
Buchholz, D.
1996-01-01
A general method is presented that allows one to determine from the local gauge invariant observables of a quantum field theory the underlying particle and symmetry structures appearing at the lower (ultraviolet) end of the spatio-temporal scale. Particles that are confined to small scales, i.e. do not appear in the physical spectrum, can be uncovered in this way without taking recourse to gauge fields or indefinite metric spaces. In this way notions such as quark, gluon, colour symmetry and confinement acquire a new and intrinsic meaning which is stable under gauge or duality transformations. The method is illustrated by the example of the Schwinger model. (orig.)
Study of quark structure functions
International Nuclear Information System (INIS)
Dao, F.T.; Flaminio, E.; Lai, K.; Metcalf, M.; Wang, L.
1977-01-01
The quark structure functions of the proton are determined through a combined analysis of the reactions pN → ll-barX and eN → eX. The valence-quark structure function of the pion is also given by analyzing the πN → μμ-barX data measured by the Branson et al
Hadron interactions in quark models
International Nuclear Information System (INIS)
Narodetskij, I.M.
1987-01-01
Some recent developments on the study of quark degrees of freedom in hadron scattering at intermediate energy are reviewed. Physical foundations of the P-matrix approach and the Quark Compound Bag method are discussed including applications to pion-pion, pion-nucleon, nucleon-nucleon and three-nucleon systems
International Nuclear Information System (INIS)
Yu, L.H.
1998-01-01
Recent advances in self-amplified spontaneous emission (SASE) experiments stimulate interest in quantitative comparison of measurements with theory. In this paper we show that the widely used simulation code TDA3D, developed by Tran and Wurtele [Comput. Phys. Commun. 54, 263 (1989)] even though a single frequency code, can be used to determine the output power in the SASE process with excellent approximation in the exponential growth regime. The method applies when the gain is not very high, which is a special advantage, because when the gain is not very high, the analytical calculation is particularly difficult since the exponential growing term does not dominate. The analysis utilizes a scaling relation between the output power and the number of simulation particles in the code TDA3D: left-angle P right-angle=N λ ' /N λ left-angle P ' right-angle, where left-angle P right-angle is the output power and N λ is the line density of the electrons, while left-angle P ' right-angle is the calculated output power using a line density N λ ' of the number of simulation particles in the code TDA3D. Because of the scaling property, the number of simulation particles can be taken to be many orders of magnitude less than the actual experiment. Comparison of our results with experiment yields new insight into the SASE process. copyright 1998 The American Physical Society
Directory of Open Access Journals (Sweden)
Jichul Ryu
2016-04-01
Full Text Available In this study, 52 asymptotic Curve Number (CN regression equations were developed for combinations of representative land covers and hydrologic soil groups. In addition, to overcome the limitations of the original Long-term Hydrologic Impact Assessment (L-THIA model when it is applied to larger watersheds, a watershed-scale L-THIA Asymptotic CN (ACN regression equation model (watershed-scale L-THIA ACN model was developed by integrating the asymptotic CN regressions and various modules for direct runoff/baseflow/channel routing. The watershed-scale L-THIA ACN model was applied to four watersheds in South Korea to evaluate the accuracy of its streamflow prediction. The coefficient of determination (R2 and Nash–Sutcliffe Efficiency (NSE values for observed versus simulated streamflows over intervals of eight days were greater than 0.6 for all four of the watersheds. The watershed-scale L-THIA ACN model, including the asymptotic CN regression equation method, can simulate long-term streamflow sufficiently well with the ten parameters that have been added for the characterization of streamflow.
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)
Quark models in hadron physics
International Nuclear Information System (INIS)
Phatak, Shashikant C.
2007-01-01
In this talk, we review the role played by the quark models in the study of interaction of strong, weak and electromagnetic probes with hadrons at intermediate and high momentum transfers. By hadrons, we mean individual nucleons as well as nuclei. We argue that at these momentum transfers, the structure of hadrons plays an important role. The hadron structure of the hadrons is because of the underlying quark structure of hadrons and therefore the quark models play an important role in determining the hadron structure. Further, the properties of hadrons are likely to change when these are placed in nuclear medium and this change should arise from the underlying quark structure. We shall consider some quark models to look into these aspects. (author)
Energy Technology Data Exchange (ETDEWEB)
De Ford, D
1988-01-01
The objective of this research is to provide a novel approach to the problem of scale-up of fermentations. The work subscribes the idea that two regions appear in bioreactors as the volume increases. The first is where high oxygen transfer occurs and the second is where low oxygen transfer occurs. It is assumed that organisms grown in a stirred tank fermenter travel in a cyclical manner through these two regions. A dimensionless factor is developed, the bioreactor number. Using this number the performance of any stirred tank fermenter can be described as a function of its geometry, operating conditions and physical properties of media. A mathematical model for the prediction of the physiological response of aerobic micro-organisms (specific growth rate, final cell concentration and product synthesis) as a function of the bioreactor number is also developed. It was adjusted by using the results of fermentations performed in a specially designed experimental rig allowing the simulation of fermenters with various bioreactor numbers. If the bioreactor and physiological models are linked it is possible to predict how micro-organisms respond when geometry, operating conditions or media properties are changed in a bioreactor. This approach is a tool for decision making in the design and operation of fermenters.
International Nuclear Information System (INIS)
Schramm, D.N.; Fields, B.; Thomas, D.
1992-01-01
The possible implications of the quark-hadron transition for cosmology are explored. Possible surviving signatures are discussed. In particular, the possibility of generating a dark matter candidate such as strange nuggets or planetary mass black holes is noted. Much discussion is devoted to the possible role of the transition for cosmological nucleosynthesis. It is emphasized that even an optimized first order phase transition will not significantly alter the nucleosynthesis constraints on the cosmological baryon density nor on neutrino counting. However, it is noted that Be and B observations in old stars may eventually be able to be a signature of a cosmologically significant quark-hadron transition. It is pointed out that the critical point in this regard is whether the observed B/Be ratio can be produced by spallation processes or requires cosmological input. Spallation cannot produce a B/Be ratio below 7.6. A supporting signature would be Be and B ratios to oxygen that greatly exceed galactic values. At present, all data is still consistent with a spallagenic origin
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
Top quark production at the LHC (single top and tt-bar cross sections)
International Nuclear Information System (INIS)
Lange, J.
2014-01-01
With the large number of top quarks produced at the LHC, top quark physics enters an era of precision and properties measurements. This article reviews the recent advances in top quark cross section measurements performed by ATLAS and CMS using data recorded in 2011 with integrated luminosities up to 5 fb -1 . They include precision inclusive cross sections, the establishment of challenging channels, first differential cross section measurements and single top production. An overall good agreement with Standard Model predictions is observed
International Nuclear Information System (INIS)
Ruppert, J.; Rahmede, C.; Bleicher, M.
2005-01-01
Within the ADD-model, we elaborate an idea by Vacavant and Hinchliffe [J. Phys. G 27 (2001) 1839] and show quantitatively how to determine the fundamental scale of TeV-gravity and the number of compactified extra dimensions from data at LHC. We demonstrate that the ADD-model leads to strong correlations between the missing E T in gravitons at different center of mass energies. This correlation puts strong constraints on this model for extra dimensions, if probed at s=5.5 TeV and s=14 TeV at LHC
Tiselj, Iztok
2014-12-01
Channel flow DNS (Direct Numerical Simulation) at friction Reynolds number 180 and with passive scalars of Prandtl numbers 1 and 0.01 was performed in various computational domains. The "normal" size domain was ˜2300 wall units long and ˜750 wall units wide; size taken from the similar DNS of Moser et al. The "large" computational domain, which is supposed to be sufficient to describe the largest structures of the turbulent flows was 3 times longer and 3 times wider than the "normal" domain. The "very large" domain was 6 times longer and 6 times wider than the "normal" domain. All simulations were performed with the same spatial and temporal resolution. Comparison of the standard and large computational domains shows the velocity field statistics (mean velocity, root-mean-square (RMS) fluctuations, and turbulent Reynolds stresses) that are within 1%-2%. Similar agreement is observed for Pr = 1 temperature fields and can be observed also for the mean temperature profiles at Pr = 0.01. These differences can be attributed to the statistical uncertainties of the DNS. However, second-order moments, i.e., RMS temperature fluctuations of standard and large computational domains at Pr = 0.01 show significant differences of up to 20%. Stronger temperature fluctuations in the "large" and "very large" domains confirm the existence of the large-scale structures. Their influence is more or less invisible in the main velocity field statistics or in the statistics of the temperature fields at Prandtl numbers around 1. However, these structures play visible role in the temperature fluctuations at low Prandtl number, where high temperature diffusivity effectively smears the small-scale structures in the thermal field and enhances the relative contribution of large-scales. These large thermal structures represent some kind of an echo of the large scale velocity structures: the highest temperature-velocity correlations are not observed between the instantaneous temperatures and
Strange particle production from quark matter droplets
International Nuclear Information System (INIS)
Werner, K.; Hladik, M.
1995-01-01
We recently introduced new methods to study ultrarelativistic nuclear scattering by providing a link between the string model approach and a thermal description. The string model is used to provide information about fluctuations in energy density. Regions of high energy density are considered to be quark matter droplets and treated macroscopically. At SPS energies, we find mainly medium size droplets---with energies up to few tens of Gev. A key issue is the microcanonical treatment of individual quark matter droplets. Each droplet hadronizes instantaneously according to the available n-body phase space. Due to the huge number of possible hadron configurations, special Monte Carlo techniques have been developed to calculate this disintegration. We present results concerning the production of strange particles from such a hadronization as compared to string decay. copyright 1995 American Institute of Physics
The potential model of coloured quarks
International Nuclear Information System (INIS)
Greenberg, O.W.
1981-01-01
The success of the additive potential model of colored quarks for the masses, decay rates, and other properties of single mesons and baryons does not imply that this model can yield the observed meson-nucleon and nucleon-nucleon interactions. We give a comprehensive discussion of this issue. In agreement with previous authors, we conclude that, on the contrary, this model predicts inverse-power color-analog van der Waals potentials between separated hadrons which are in substantial contradiction with experimental data. We also discuss pathologies of non-abelian confining potentials, and show that the hamiltonian is unbounded below for an arbitrary number of quarks and antiquarks in a definite color state for all color states, except the singlet, triplet, and antitriplet. (orig.)
Lattice analysis of SU(2) chromodynamics with light quarks
International Nuclear Information System (INIS)
Laermann, E.
1986-01-01
I report on the Monte-Carlo simulation of a SU(2) lattice gauge theory which includes dynamical Kogut-Susskind quarks. On a 16*8 3 lattice the masses of ρ and π mesons are studied, the condensate measuring the chiral symmetry breaking determined, and the potential between static quarks measured. Extrapolations to vanishing quark mass yield a finite ρ mass but a value for the π mass which is compatible with zero, as well as a result different from zero for the quark condensate in accordance with the spontaneous breaking of the chiral symmetry of massless non-Abelian gauge theories. The shape of the q-anti q potential equals the pure gauge potential for small to intermediate distances. However at large distances (σ(fm)) deviations from the linear increase are indicated as they are expected due to the breakup of the flux tube between heavy quarks because of spontaneous quark-pair production. For all numerical calculations it is common that they favor a value for the scale parameter Λsub(anti Manti S)(N F =4) of quantum chromodynamics which is smaller than in the pure gauge field theory. (orig.) [de
Reproducing the Higgs boson data with vector-like quarks
International Nuclear Information System (INIS)
Bonne, N.; Moreau, G.
2012-01-01
Vector-Like (VL) quarks arise in the main alternatives to the supersymmetric extensions of the Standard Model (SM). Given the experimental possibility of a 125 GeV Higgs boson with rates significantly different from the SM expectations, it is motivating to study the effects of VL quarks on the Higgs boson cross sections and branching ratios. We perform a systematic search for the minimal field contents and gauge group representations of VL quarks able to significantly improve the fit of the measured Higgs rates, and simultaneously, to satisfy the direct constraints on VL quark masses as well as the electro-weak precision tests. In particular, large enhancements can be achieved in certain diphoton channels - as pointed out by both the ATLAS and CMS Collaborations - optimizing then the Higgs rate fit. This is a consequence of the introduction of VL quarks, with high electric charges of 8/3 or -7/3, which are exchanged in the Higgs-to-diphoton loop. Interestingly, the field contents and formal Higgs couplings obtained here are similar to those of scenarios in warped/composite frameworks arising from different motivations. The various exotic-charge quarks predicted, possibly below the TeV scale, might lead to a rich phenomenology soon at the LHC.
Infrared fixed point solution for the top quark mass and unification of couplings in the MSSM
International Nuclear Information System (INIS)
Bardeen, W.A.; Carena, M.; Pokorski, S.; Wagner, C.E.M.
1993-08-01
We analyze the implications of the infrared quasi fixed point solution for the top quark mass in the Minimal Supersymmetric Standard Model. This solution could explain in a natural way the relatively large value of the top quark mass and, if confirmed experimentally, may be suggestive of the onset of nonperturbative physics at very high energy scales. In the framework of grand unification, the expected bottom quark -- tau lepton Yukawa coupling unification is very sensitive to the fixed point structure of the top quark mass. For the presently allowed values of the electroweak parameters and the bottom quark mass, the Yukawa coupling unification implies that the top quark mass must be within ten percent of its fixed point values
Light-quark, heavy-quark systems: An update
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.
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
Feldmann, Daniel; Bauer, Christian; Wagner, Claus
2018-03-01
We present results from direct numerical simulations (DNS) of turbulent pipe flow at shear Reynolds numbers up to Reτ = 1500 using different computational domains with lengths up to ?. The objectives are to analyse the effect of the finite size of the periodic pipe domain on large flow structures in dependency of Reτ and to assess a minimum ? required for relevant turbulent scales to be captured and a minimum Reτ for very large-scale motions (VLSM) to be analysed. Analysing one-point statistics revealed that the mean velocity profile is invariant for ?. The wall-normal location at which deviations occur in shorter domains changes strongly with increasing Reτ from the near-wall region to the outer layer, where VLSM are believed to live. The root mean square velocity profiles exhibit domain length dependencies for pipes shorter than 14R and 7R depending on Reτ. For all Reτ, the higher-order statistical moments show only weak dependencies and only for the shortest domain considered here. However, the analysis of one- and two-dimensional pre-multiplied energy spectra revealed that even for larger ?, not all physically relevant scales are fully captured, even though the aforementioned statistics are in good agreement with the literature. We found ? to be sufficiently large to capture VLSM-relevant turbulent scales in the considered range of Reτ based on our definition of an integral energy threshold of 10%. The requirement to capture at least 1/10 of the global maximum energy level is justified by a 14% increase of the streamwise turbulence intensity in the outer region between Reτ = 720 and 1500, which can be related to VLSM-relevant length scales. Based on this scaling anomaly, we found Reτ⪆1500 to be a necessary minimum requirement to investigate VLSM-related effects in pipe flow, even though the streamwise energy spectra does not yet indicate sufficient scale separation between the most energetic and the very long motions.
A search for quark compositeness at the LHC. Dijet angular distributions
International Nuclear Information System (INIS)
Usubov, Z.U.; Abdinov, O.B.
1999-01-01
The effects of dijet angular distributions coming from a model of quark compositeness are considered. The influence of the parton distribution function, calorimeter non-linearity and energy resolution is investigated. The data sensitivity to the quark compositeness scale for low and high LHC luminosity is studied
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.
Malka, Elad; Shvarts, Dov
2017-10-01
We re-examine the way 2/3D effects on scaling laws for ignition metrics, such as the generalized Lawson Criterion (GLC) and the Ignition Threshold Factor (ITF). These scaling laws were derived for 1D symmetrical case and 2/3D perturbations [Hann et al. PoP 2010; Lindl et al., PoP 2014; Betti et al., PoP 2010]. The main cause for the difference between the 1D and the 2/3D scaling laws in those works, is heat conduction losses from the hot-spot bubbles to the cold shell [Kishony and Shvarts, PoP 2001]. This ``dry out'' of the bubbles is the dominant mechanism for intermediate mode number perturbations (6hot spot. These two effects do not have an effective 1D analogue and therefore needs a more complicated model. A consistent extension of the ignition metrics for l <=6, accounting for both energy loss mechanisms, will be presented and compared with previous models and results. This work was supported by the LLNL under subcontract B614207.
A precise characterisation of the top quark electro-weak vertices at the ILC
Energy Technology Data Exchange (ETDEWEB)
Amjad, M.S. [Laboratoire de l' Accelerateur Lineaire (LAL), Centre Scientifique d' Orsay, BP 34, Orsay Cedex (France); COMSATS Institute of Information Technology, Islamabad (Pakistan); Bilokin, S.; Poeschl, R.; Richard, F.; Rouene, J. [Laboratoire de l' Accelerateur Lineaire (LAL), Centre Scientifique d' Orsay, BP 34, Orsay Cedex (France); Boronat, M.; Garcia, I.G.; Perello, M.; Ros, E.; Vos, M. [Universitat de Valencia CSIC, IFIC, Paterna (Spain); Doublet, P. [Universitat de Valencia CSIC, IFIC, Paterna (Spain); Universite Paris-Sud, IUT d' Orsay, Orsay Cedex (France); Frisson, T. [Laboratoire de l' Accelerateur Lineaire (LAL), Centre Scientifique d' Orsay, BP 34, Orsay Cedex (France); CERN, Geneva 23 (Switzerland); Femenia, P.R. [Universitat de Valencia CSIC, IFIC, Paterna (Spain); Technische Universitaet Muenchen, Garching (Germany)
2015-10-15
Top quark production in the process e{sup +}e{sup -} → t anti t at a future linear electron positron collider with polarised beams is a powerful tool to determine indirectly the scale of new physics. The presented study, based on a detailed simulation of the ILD detector concept, assumes a centre-of-mass energy of √(s) = 500 GeV and a luminosity of L = 500 fb{sup -1} equally shared between the incoming beam polarisations of P{sub e{sup -}}, P{sub e{sup +}} = ±0.8, -+0.3. Events are selected in which the top pair decays semi-leptonically and the cross sections and the forward-backward asymmetries are determined. Based on these results, the vector, axial vector and tensorial CP conserving couplings are extracted separately for the photon and the Z{sup 0} component. With the expected precision, a large number of models in which the top quark acts as a messenger to new physics can be distinguished with many standard deviations. This will dramatically improve expectations from e.g. the LHC for electro-weak couplings of the top quark. (orig.)
How the physicists nailed the quarks
International Nuclear Information System (INIS)
Anon.
1985-01-01
The paper reviews quarks, from its prediction in 1962, to the experiments confirming its existence in the 1970's and 1980's. The elementary particles of matter; building particles from quarks; why quarks can never be isolated; and the six quarks; are all discussed. (U.K.)
Baryons in the unquenched quark model
Energy Technology Data Exchange (ETDEWEB)
Bijker, R.; Díaz-Gómez, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, AP 70-543, 04510 Mexico DF (Mexico); Lopez-Ruiz, M. A. [Physics Department and Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States); Santopinto, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, via Dodecaneso 33, I-16146 Italy (Italy)
2016-07-07
In this contribution, we present the unquenched quark model as an extension of the constituent quark model that includes the effects of sea quarks via a {sup 3}P{sub 0} quark-antiquark pair-creation mechanism. Particular attention is paid to the spin and flavor content of the proton, magnetic moments and β decays of octet baryons.
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.)
International Nuclear Information System (INIS)
Menzione, A.
1995-10-01
Most of the material presented in this report, comes from contributions to the parallel session PL20 of this conference. We summarise the experimental results of direct production of Top quarks, coming from the CDF and C0 Collaborations at Fermilab, and compare these results to what one expects within current theoretical understanding. Particular attention is given to new results such as all hadronic modes of t bar t decay. As far as the mass is concerned, a comparison is made with precision measurements of related quantities, coming from LEP and other experiments. An attempt is made to look at the medium-term future and understand which variables and with what accuracy one can measure them with increased integrated luminosity
Quarks and numerical simulation
International Nuclear Information System (INIS)
Weingarten, D.
1996-01-01
This work deals with the quantum chromodynamics and the theory of quarks's behaviour. The experimentation supports this theory but until now no computation have prove it. The resolution of the mathematic equations were far beyond the capability of human or the quickest computer of the seventies. A dedicated computer was built: the GF11. The mass of eight hadrons was computed in 91. In 95, a new particle was found by computation. The author explains the mathematical modeling of chromodynamics and the methods to solve it. It requires 10 17 arithmetic operations. So specific computer is needed. GF11 uses 566 processors in parallel. New machines hundred of times more efficient will be needed to go further. That will be a new tool for theorician physicists. (O.M.). 9 refs., 2 figs., 1 tab
Dihadron fragmentation functions in the quark-jet model: Transversely polarized quarks
Matevosyan, Hrayr H.; Kotzinian, Aram; Thomas, Anthony W.
2018-01-01
Within the most recent extension of the quark-jet hadronization framework, we explore the transverse-polarization-dependent dihadron fragmentation functions (DiFFs) H1∢ and H1⊥ of a quark into π+π- pairs. Monte Carlo (MC) simulations are employed to model polarized quark hadronization and calculate the corresponding number densities. These, in turn, are used to extract the Fourier cosine moments of the DiFFs H1∢ and H1⊥. A notable finding is that there are previously unnoticed apparent discrepancies between the definitions of the so-called interference DiFF (IFF) H1∢ , entering the cross sections for two-hadron semi-inclusive electroproduction, and those involved in the production of two pairs of hadrons from back-to-back jets in electron-positron annihilation. This manuscript completes the studies of all four leading-twist DiFFs for unpolarized hadron pairs within the quark-jet framework, following our previous work on the helicity-dependent DiFF G1⊥.
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)
Directory of Open Access Journals (Sweden)
Daniel Pettersson
2016-01-01
later the growing importance of transnational agencies and international, regional and national assessments. How to reference this article Pettersson, D., Popkewitz, T. S., & Lindblad, S. (2016. On the Use of Educational Numbers: Comparative Constructions of Hierarchies by Means of Large-Scale Assessments. Espacio, Tiempo y Educación, 3(1, 177-202. doi: http://dx.doi.org/10.14516/ete.2016.003.001.10
Quark Condensate in the Strange Matter
Institute of Scientific and Technical Information of China (English)
LU Chang-Fang; LU" Xiao-Fu
2003-01-01
In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including N, Σ, Ξ, and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that 〈π→2〉 plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number.
Transition in x-ray yield, mass scaling observed in the high-wire-number, plasma-shell regime
International Nuclear Information System (INIS)
Whitney, K.G.; Pulsifer, P.E.; Apruzese, J.P.; Thornhill, J.W.; Davis, J.; Sanford, T.W.L.; Mock, R.C.; Nash, T.J.
1999-01-01
Initial calculations, based on classical transport coefficients and carried out to predict the efficiency with which the implosion kinetic energy of aluminum Z pinches could be thermalized and converted into kilovolt x-rays, predicted a sharp transition between m 2 and m yield scaling, where m is the aluminum array mass. Later, when ad hoc increases in the heat conductivity and artificial viscosity were introduced into these calculations and the densities that were achieved on axis were sharply reduced, the transition from m 2 to m scaling was found to have shifted, but was otherwise still fairly sharp and well-defined. The location of these breakpoint curves defined the locus of implosion velocities at which the yields would obtain their maximum for different mass arrays. The first such mass breakpoint curve that was calculated is termed hard, while the second is termed soft. Early 24, 30, and 42 aluminum wire experiments on the Saturn accelerator at the Sandia National laboratories confirmed the predictions of the soft breakpoint curve calculations. In this talk, the authors present results from a more recent set of aluminum experiments on Saturn, in which the array mass was varied at a fixed array radius and in which the radius was varied for a fixed mass. In both sets of experiments, the wire numbers were large: in excess of 92 and generally 136 or 192. In this high-wire-number regime, the wire plasmas are calculated to merge to form a plasma shell prior to significant radial implosion. Large wire number has been found to improve the pinch compressibility, and the analysis of these experiments in the shell regime shows that they come very close to the original predictions of the hard breakpoint curve calculations. A discussion of these detailed comparisons will be presented
International Nuclear Information System (INIS)
Greenberg, O.W.
1982-01-01
Quarks as fundamental constituents of hadrons play a central role in elementary particle physics. We give an annotated bibliography of references to quarks and related topics in elementary particle physics, as well as to the role of quarks in areas outside elementary particle physics, such as nuclear physics, and astrophysics and cosmology. We label references E (elementary), I (intermediate), and A (advanced) to guide the reader. Articles selected for incorporation in a reprint volume (to be published separately by the American Association of Physics Teachers) are indicated by an an asterisk. A short list of particularly helpful elementary and intermediate references is indicated by a star
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
Holographic lessons for quark dynamics
Chernicoff, Mariano; García, J. Antonio; Güijosa, Alberto; Pedraza, Juan F.
2012-05-01
We give a brief overview of recent results obtained through the gauge/gravity correspondence, concerning the propagation of a heavy quark in strongly coupled conformal field theories (such as {N}=4 super-Yang-Mills), both at zero and finite temperature. In the vacuum, we discuss energy loss, radiation damping, signal propagation and radiation-induced fluctuations. In the presence of a thermal plasma, our emphasis is on early-time energy loss, screening and quark-antiquark evolution after pair creation. Throughout, quark dynamics is seen to be efficiently encapsulated in the usual string worldsheet dynamics.
Energy Technology Data Exchange (ETDEWEB)
Harari, H
1976-01-01
The experimental information which was accumulated in the last 18 months in e/sup +/e/sup -/ collisions and ..nu..N scattering indicates that more than four kinds of quarks are already present. Six different pieces of evidence for the existence of six quarks: the triangle anomalies, the value of R, psi-spectroscopy, neutrino processes, CP-violation and the possible existence of V+A currents are discussed. It is concluded that there is strong (but not yet conclusive) evidence for the existence of six quarks and six leptons.
International Nuclear Information System (INIS)
Harari, Haim
The experimental information which was accumulated in the last 18 months in e + e - collisions and neutrino+N scattering indicates that more than four kinds of quarks are already present. Six different pieces of evidence for the existence of six quarks are discussed: the triangle anomalies, the value of R, psi-spectroscopy, neutrino processes, CP-violation and the possible existence of V+A currents. It is concluded that there is strong (but not yet conclusive) evidence for the existence of six quarks and six leptons
International Nuclear Information System (INIS)
Thorndike, E.H.; Poling, R.A.
1988-01-01
Recent experimental results on the decay of b-flavored hadrons are reviewed. Substantial progress has been made in the study of exclusive and inclusive B-meson decays, as well as in the theoretical understanding of these processes. The two most prominent developments are the continuing failure to observe evidence of decays of the b quark to a u quark rather than a c quark, and the surprisingly high level of B 0 -anti B 0 mixing which has recently been reported by the ARGUS collaboration. Notwithstanding these results, we conclude that the health of the Standard Model is excellent. (orig.)
Quark chiral condensate from the overlap quark propagator
Wang, Chao; Bi, Yujiang; Cai, Hao; Chen, Ying; Gong, Ming; Liu, Zhaofeng
2017-05-01
From the overlap lattice quark propagator calculated in the Landau gauge, we determine the quark chiral condensate by fitting operator product expansion formulas to the lattice data. The quark propagators are computed on domain wall fermion configurations generated by the RBC-UKQCD Collaborations with N f = 2+1 flavors. Three ensembles with different light sea quark masses are used at one lattice spacing 1/a = 1.75(4) GeV. We obtain in the SU(2) chiral limit. Supported by National Natural Science Foundation of China (11575197, 11575196, 11335001, 11405178), joint funds of NSFC (U1632104, U1232109), YC and ZL acknowledge the support of NSFC and DFG (CRC110)
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
Quark-anti-quark potential in N=4 SYM
Energy Technology Data Exchange (ETDEWEB)
Gromov, Nikolay [Mathematics Department, King’s College London,The Strand, London WC2R 2LS (United Kingdom); St. Petersburg INP,Gatchina, 188 300, St.Petersburg (Russian Federation); Levkovich-Maslyuk, Fedor [Mathematics Department, King’s College London,The Strand, London WC2R 2LS (United Kingdom); Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden)
2016-12-22
We construct a closed system of equations describing the quark-anti-quark potential at any coupling in planar N=4 supersymmetric Yang-Mills theory. It is based on the Quantum Spectral Curve method supplemented with a novel type of asymptotics. We present a high precision numerical solution reproducing the classical and one-loop string predictions very accurately. We also analytically compute the first 7 nontrivial orders of the weak coupling expansion. Moreover, we study analytically the generalized quark-anti-quark potential in the limit of large imaginary twist to all orders in perturbation theory. We demonstrate how the QSC reduces in this case to a one-dimensional Schrodinger equation. In the process we establish a link between the Q-functions and the solution of the Bethe-Salpeter equation.
Top quark studies at hadron colliders
Energy Technology Data Exchange (ETDEWEB)
Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)
1997-01-01
The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.
Quark virtuality and QCD vacuum condensates
International Nuclear Information System (INIS)
Zhou Lijuan; Ma Weixing
2004-01-01
Based on the Dyson-Schwinger equations (DSEs) in the 'rainbow' approximation, the authors investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, authors calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ u,d 2 =0.7 GeV 2 for u, d quarks, and λ s 2 =1.6 GeV 2 for s quark. The theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions
Top quark studies at hadron colliders
International Nuclear Information System (INIS)
Sinervo, P.K.
1997-01-01
The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented
Top quark studies at hadron colliders
International Nuclear Information System (INIS)
Sinervo, P.K.
1996-08-01
The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and D null collaborations are reviewed, including the top quark cross section, mass, branching fractions and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented
Theoretical estimation of Photons flow rate Production in quark gluon interaction at high energies
Al-Agealy, Hadi J. M.; Hamza Hussein, Hyder; Mustafa Hussein, Saba
2018-05-01
photons emitted from higher energetic collisions in quark-gluon system have been theoretical studied depending on color quantum theory. A simple model for photons emission at quark-gluon system have been investigated. In this model, we use a quantum consideration which enhances to describing the quark system. The photons current rate are estimation for two system at different fugacity coefficient. We discussion the behavior of photons rate and quark gluon system properties in different photons energies with Boltzmann model. The photons rate depending on anisotropic coefficient : strong constant, photons energy, color number, fugacity parameter, thermal energy and critical energy of system are also discussed.
Quark flavour observables in the Littlest Higgs model with T-parity after LHC Run 1.
Blanke, Monika; Buras, Andrzej J; Recksiegel, Stefan
2016-01-01
The Littlest Higgs model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. The latter originate in the interactions of ordinary quarks and leptons with heavy mirror quarks and leptons that are mediated by new heavy gauge bosons. Also a heavy fermionic top partner is present in this model which communicates with the SM fermions by means of standard [Formula: see text] and [Formula: see text] gauge bosons. We present a new analysis of quark flavour observables in the LHT model in view of the oncoming flavour precision era. We use all available information on the CKM parameters, lattice QCD input and experimental data on quark flavour observables and corresponding theoretical calculations, taking into account new lower bounds on the symmetry breaking scale and the mirror quark masses from the LHC. We investigate by how much the branching ratios for a number of rare K and B decays are still allowed to depart from their SM values. This includes [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]. Taking into account the constraints from [Formula: see text] processes, significant departures from the SM predictions for [Formula: see text] and [Formula: see text] are possible, while the effects in B decays are much smaller. In particular, the LHT model favours [Formula: see text], which is not supported by the data, and the present anomalies in [Formula: see text] decays cannot be explained in this model. With the recent lattice and large N input the imposition of the [Formula: see text] constraint implies a significant suppression of the branching ratio for [Formula: see text] with respect to its SM value while allowing only for small modifications of [Formula: see text]. Finally, we investigate how the LHT physics could be distinguished from other models by means of indirect measurements and
Effects of dynamical quarks in UKQCD simulations
International Nuclear Information System (INIS)
Allton, Chris
2002-01-01
Recent results from the UKQCD Collaboration's dynamical simulations are presented. The main feature of these ensembles is that they have a fixed lattice spacing and volume, but varying sea quark mass from infinite (corresponding to the quenched simulation) down to roughly that of the strange quark mass. The main aim of this work is to uncover dynamical quark effects from these 'matched' ensembles. We obtain some evidence of dynamical quark effects in the static quark potential with less effects in the hadronic spectrum
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
A precise determination of the top-quark pole mass
International Nuclear Information System (INIS)
Wang, Sheng-Quan; Wu, Xing-Gang; Si, Zong-Guo; Brodsky, Stanley J.
2018-01-01
The Principle of Maximum Conformality (PMC) provides a systematic way to eliminate the renormalization scheme and renormalization scale uncertainties for high-energy processes. We have observed that by applying PMC scale setting, one obtains comprehensive and self-consistent pQCD predictions for the top-quark pair total cross section and the top-quark pair forward-backward asymmetry in agreement with the measurements at the Tevatron and LHC. As a step forward, in the present paper, we determine the top-quark pole mass via a detailed comparison of the top-quark pair cross section with the measurements at the Tevatron and LHC. The results for the top-quark pole mass are m t = 174.6 +3.1 -3.2 GeV for the Tevatron with √(S) = 1.96 TeV, m t = 173.7 ± 1.5 and 174.2 ± 1.7 GeV for the LHC with √(S) = 7 and 8 TeV, respectively. Those predictions agree with the average, 173.34 ± 0.76 GeV, obtained from various collaborations via direct measurements. The consistency of the pQCD predictions using the PMC with all of the collider measurements at different energies provides an important verification of QCD. (orig.)
A precise determination of the top-quark pole mass
Wang, Sheng-Quan; Wu, Xing-Gang; Si, Zong-Guo; Brodsky, Stanley J.
2018-03-01
The Principle of Maximum Conformality (PMC) provides a systematic way to eliminate the renormalization scheme and renormalization scale uncertainties for high-energy processes. We have observed that by applying PMC scale setting, one obtains comprehensive and self-consistent pQCD predictions for the top-quark pair total cross section and the top-quark pair forward-backward asymmetry in agreement with the measurements at the Tevatron and LHC. As a step forward, in the present paper, we determine the top-quark pole mass via a detailed comparison of the top-quark pair cross section with the measurements at the Tevatron and LHC. The results for the top-quark pole mass are m_t=174.6^{+3.1}_{-3.2} GeV for the Tevatron with √{S}=1.96 TeV, m_t=173.7± 1.5 and 174.2± 1.7 GeV for the LHC with √{S} = 7 and 8 TeV, respectively. Those predictions agree with the average, 173.34± 0.76 GeV, obtained from various collaborations via direct measurements. The consistency of the pQCD predictions using the PMC with all of the collider measurements at different energies provides an important verification of QCD.
New signals for vector-like down-type quark in U(1) of E{sub 6}
Energy Technology Data Exchange (ETDEWEB)
Das, Kasinath; Rai, Santosh Kumar [Harish-Chandra Research Institute, HBNI, Regional Centre for Accelerator-based Particle Physics, Allahabad (India); Li, Tianjun [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Nandi, S. [Oklahoma State University, Department of Physics and Oklahoma Center for High Energy Physics, Stillwater, OK (United States)
2018-01-15
We consider the pair production of vector-like down-type quarks in an E{sub 6} motivated model, where each of the produced down-type vector-like quark decays into an ordinary Standard Model light quark and a singlet scalar. Both the vector-like quark and the singlet scalar appear naturally in the E{sub 6} model with masses at the TeV scale with a favorable choice of symmetry breaking pattern. We focus on the non-standard decay of the vector-like quark and the new scalar which decays to two photons or two gluons. We analyze the signal for the vector-like quark production in the 2γ+ ≥ 2j channel and show how the scalar and vector-like quark masses can be determined at the Large Hadron Collider. (orig.)
Quark effects in nuclear physics
International Nuclear Information System (INIS)
Scholten, O.
1990-01-01
The magnitude of the quark effect for low-energy nuclear physics is investigated. Coulomb energy is studied in the A=3 system in order to determine the effect of the composite structure of the nucleon. In the actual calculations a non-relativistic quark-cluster model description has been used. A nucleon size b=0.617 fm, the width of the relative wave function Φ of the quarks in the nucleon, has been assumed. It is concluded that the contribution to Coulomb energies due to quark effects are significant compared to the observed Nolen-Schiffer anomaly. However these do not provide the long searched for 'smoking gun'. When the free parameters that appear in the calculation are adjusted to reproduce the same charge form factor, the calculated anomalies are not significantly different. 2 figs., 2 tabs., 8 refs.2
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)
Quark potential of spontaneous strings
International Nuclear Information System (INIS)
German, G.; Kleinert, H.
1989-01-01
The authors present some recent developments in string models with an extrinsic curvature term in action. Particular emphasis is placed upon the static quark potential and on the thermal deconfinement properties of spontaneous strings
Dilip, Jana
2008-01-01
The ATLAS potential for the study of the top quark properties and physics beyond the Standard Model in the top quark sector, is described. The measurements of the top quark charge, the spin and spin correlations, the Standard Model decay (t-> bW), rare top quark decays associated to flavour changing neutral currents (t-> qX with X = gluon, Z, photon) and ttbar resonances are discussed. The sensitivity of the ATLAS experiment is estimated for an expected luminosity of 1fb-1 at the LHC. The full simulation of the ATLAS detector is used. For the Standard Model measurements the expected precision is presented. For the tests of physics beyond the Standard Model, the 5 sigma discovery potential (in the presence of a signal) and the 95% Confidence Level (CL) limit (in the absence of a signal) are given.
CERN. Geneva
2011-01-01
Higgs mechanism. There are various hints at deviations from the Standard Model expectation which have been observed recently by Tevatron experiments in top final states. Several signatures of new physics accessible at the LHC either suffer from top-quark production as a significant background or contain top quarks themselves. In this talk, we present results on top quark physics obtained from the first LHC data collected by the CMS experiment.They include measurements of the top pair production cross section in various channels and their combination, measurements of the top quark mass, the single top cross section, a search for new particles decaying into top pairs, and a first look at the charge asymmetry.
Dumé, Belle
2003-01-01
"Physicists working at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the US say that they have come closer than ever before to creating a quark-gluon plasma" (0.5 page)
Colour screening and quark confinement
International Nuclear Information System (INIS)
Mack, G.
1978-03-01
It is proposed that in Quantum Chromodynamics the colour charge of gluons and of anything with zero triality is screened by a dynamical Higgs mechanism with Higgs scalars made out of gluons. The center Z 3 of the gauge group SU(3) is left unbroken in this way, and single quarks, which have nonzero triality, cannot be screened. Long range forces between them persist therefore. Given that the Higgs mechanism produces a mass gap, the most favorable configuration of field lines between e.g. quark and antiquark will be in strings analogous to magnetic field lines in a superconductor. The strings confine the quarks. The screening mechanism, on the other hand, produces not only the mass gap (which leads to string formation) but is also responsible for saturation of forces, i.e. absence of bound states of six quarks etc. (orig.) [de
Colour screening and quark confinement
International Nuclear Information System (INIS)
Mack, G.
1978-01-01
It is proposed that in quantum chromodynamics the colour charge of gluons and of anything with zero triality is screened by a dynamic Higgs mechanism with Higgs scalars made out of gluons, but the center Z 3 of the gauge group SU(3) is left unbroken, and single quarks, which have nonzero triality, are not screened. Long range forces between them persist therefore. Given that the Higgs mechanism produces a mass gap, the most favourable configuration of field lines between e.g., quark and antiquark will be in strings analogous to magnetic field lines in a superconductor. The string confine the quarks. The screening mechanism, on the other hand, produces not only the mass gap (which leads to string formation) but is also responsible for saturation of forces, i.e. absence of bound states of six quarks, etc. (Auth.)
Generation labels in composite models for quarks and leptons
International Nuclear Information System (INIS)
Harari, H.; Seiberg, N.
1981-03-01
Models in which quarks and leptons are approximately massless composites of fundamental massless fermions which are confined by a hypercolor force are considered. The fundamental Lagrangian exhibits an axial U(1)sub(X) symmetry which is broken by hypercolor instantons, leaving a conserved discrete subgroup. It is proposed that the distinction between different generations of quarks and leptons is given by the X-number. The resulting generation labelling scheme does not lead to massless Goldstone bosons or to new anomalies and is based on a quantum number which is already contained in the theory. The dynamical rishon model is described as an illustrative example. (H.K.)
Nitta, Tatsumi; The ATLAS collaboration
2017-01-01
By colliding protons and examining particles emitted from the collisions, the Large Hadron Collider aims to study the interactions of quarks and gluons at the highest energies accessible in a controlled experimental way. In such collisions, W bosons or top quarks which have TeV scale momentum can be accessible. Reconstructing such boosted jets are becoming important. In particular, the ability to identify original particle that decays to quarks against normal QCD jets plays a central role in various searches at high energy scale. This is typically done by the use of a single physically motivated observable constructed from the constituents of the jet. In this work, multiple complementary observables are combined using boosted decision trees and neural networks to increase the ability to distinguish W bosons and top quarks from light quark jets in the ATLAS experiment.
International Nuclear Information System (INIS)
Toki, H.
2000-01-01
We discuss the research fields to be studied by the Japan Hadron Facility being planned in the site of JAERI as a joint project with Neutron Science Project. We would expect to reveal the most microscopic structure of matter using the intensity frontier proton machine. In particular, we would like to develop Quark Nuclear Physics to describe hadrons and nuclei in terms of quarks and gluons. (author)
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
Quark effects in nuclear structure
International Nuclear Information System (INIS)
Watt, A.
1987-01-01
Some experimental data in nuclear structure physics cannot be explained on the assumption that nuclei consist of inert protons and neutrons. The quark model attributes a definite internal structure to nucleons and implies that their properties should change when embedded in a nucleus. This article reviews some of the experimental evidence for these effects and discusses some new aspects of nuclear structure predicted by the quark model
International Nuclear Information System (INIS)
Li Zheng; Zhang Dongjie; Ma Linwei; West, Logan; Ni Weidou
2011-01-01
CCS is seen as an important and strategic technology option for China to reduce its CO 2 emission, and has received tremendous attention both around the world and in China. Scholars are divided on the role CCS should play, making the future of CCS in China highly uncertain. This paper presents the overall circumstances for CCS development in China, including the threats and opportunities for large scale deployment of CCS, the initial barriers and advantages that China currently possesses, as well as the current progress of CCS demonstration in China. The paper proposes the implementation of a limited number of larger scale, fully integrated CCS demonstration projects and explains the potential benefits that could be garnered. The problems with China's current CCS demonstration work are analyzed, and some targeted policies are proposed based on those observations. These policy suggestions can effectively solve these problems, help China gain the benefits with CCS demonstration soon, and make great contributions to China's big CO 2 reduction mission. - Highlights: → We analyze the overall circumstances for CCS development in China in detail. → China can garner multiple benefits by conducting several large, integrated CCS demos. → We present the current progress in CCS demonstration in China in detail. → Some problems exist with China's current CCS demonstration work. → Some focused policies are suggested to improve CCS demonstration in China.
Theory of quark mixing matrix and invariant functions of mass matrices
International Nuclear Information System (INIS)
Jarlskog, C.
1987-10-01
The outline of this talk is as follows: The origin of the quark mixing matrix. Super elementary theory of flavour projection operators. Equivalences and invariances. The commutator formalism and CP violation. CP conditions for any number of families. The 'angle' between the quark mass matrices. Application to Fritzsch and Stech matrices. References. (author)
Polarization in heavy quark decays
Energy Technology Data Exchange (ETDEWEB)
Alimujiang, K.
2006-07-01
In this thesis I concentrate on the angular correlations in top quark decays and their next.to.leading order (NLO) QCD corrections. I also discuss the leading.order (LO) angular correlations in unpolarized and polarized hyperon decays. In the first part of the thesis I calculate the angular correlation between the top quark spin and the momentum of decay products in the rest frame decay of a polarized top quark into a charged Higgs boson and a bottom quark in Two-Higgs-Doublet-Models: t({up_arrow}) {yields} b + H{sup +}. I provide closed form formulae for the O({alpha}{sub s}) radiative corrections to the unpolarized and the polar correlation functions for m{sub b}{ne}0 and m{sub b}=0. In the second part I concentrate on the semileptonic rest frame decay of a polarized top quark into a bottom quark and a lepton pair: t({up_arrow}){yields}X{sub b}+l{sup +}+{nu}{sub l}. I present closed form expressions for the O({alpha}{sub s}) radiative corrections to the unpolarized part and the polar and azimuthal correlations for m{sub b}{ne}0 and m{sub b}=0. In the last part I turn to the angular distribution in semileptonic hyperon decays. Using the helicity method I derive complete formulas for the leading order joint angular decay distributions occurring in semileptonic hyperon decays including lepton mass and polarization effects. (orig.)
Measurements of the Z partial decay width into c anti c and multiplicity of charm quarks per b decay
International Nuclear Information System (INIS)
Abreu, P.; Adam, W.; Adye, T.
2000-01-01
The partial decay width R c of the Z into c anti c quark pair and the number of charm quarks n c per b decay are measured with the DELPHI detector at LEP 1. Particle identification provides clear D 0 , D + , D s + and Λ c + signatures. The charm hadron production rate is measured in each channel by a fit to the scaled energy, impact parameter information and the invariant mass spectrum. Two measurements of R c are presented, from the D *+ production rate and from the overall charm counting, including strange charm baryon production, in c anti c events. The multiplicity n c , which includes hidden c anti c and strange charm baryon production, is inferred from the charm counting in b anti b events. The final results are R c =0.1665±0.0095 and n c =1.166±0.086. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Monty, J.P.; Lien, K.; Chong, M.S. [University of Melbourne, Department of Mechanical Engineering, Parkville, VIC (Australia); Allen, J.J. [New Mexico State University, Department of Mechanical Engineering, Las Cruces, NM (United States)
2011-12-15
A high Reynolds number boundary-layer wind-tunnel facility at New Mexico State University was fitted with a regularly distributed braille surface. The surface was such that braille dots were closely packed in the streamwise direction and sparsely spaced in the spanwise direction. This novel surface had an unexpected influence on the flow: the energy of the very large-scale features of wall turbulence (approximately six-times the boundary-layer thickness in length) became significantly attenuated, even into the logarithmic region. To the author's knowledge, this is the first experimental study to report a modification of 'superstructures' in a rough-wall turbulent boundary layer. The result gives rise to the possibility that flow control through very small, passive surface roughness may be possible at high Reynolds numbers, without the prohibitive drag penalty anticipated heretofore. Evidence was also found for the uninhibited existence of the near-wall cycle, well known to smooth-wall-turbulence researchers, in the spanwise space between roughness elements. (orig.)
Broeren, Andy P.; Woodard, Brian S.; Diebold, Jeffrey M.; Moens, Frederic
2017-01-01
Aerodynamic assessment of icing effects on swept wings is an important component of a larger effort to improve three-dimensional icing simulation capabilities. An understanding of ice-shape geometric fidelity and Reynolds and Mach number effects on the iced-wing aerodynamics is needed to guide the development and validation of ice-accretion simulation tools. To this end, wind-tunnel testing and computational flow simulations were carried out for an 8.9 percent-scale semispan wing based upon the Common Research Model airplane configuration. The wind-tunnel testing was conducted at the Wichita State University 7 by 10 ft Beech wind tunnel from Reynolds numbers of 0.8×10(exp 6) to 2.4×10(exp 6) and corresponding Mach numbers of 0.09 to 0.27. This paper presents the results of initial studies investigating the model mounting configuration, clean-wing aerodynamics and effects of artificial ice roughness. Four different model mounting configurations were considered and a circular splitter plate combined with a streamlined shroud was selected as the baseline geometry for the remainder of the experiments and computational simulations. A detailed study of the clean-wing aerodynamics and stall characteristics was made. In all cases, the flow over the outboard sections of the wing separated as the wing stalled with the inboard sections near the root maintaining attached flow. Computational flow simulations were carried out with the ONERA elsA software that solves the compressible, threedimensional RANS equations. The computations were carried out in either fully turbulent mode or with natural transition. Better agreement between the experimental and computational results was obtained when considering computations with free transition compared to turbulent solutions. These results indicate that experimental evolution of the clean wing performance coefficients were due to the effect of three-dimensional transition location and that this must be taken into account for future
Searching for color sextet quarks at high energy hardon colliders
International Nuclear Information System (INIS)
Kantar, M.
2005-01-01
We analyze the resonance and pair production of color sextet quarks and their decay modes at very high energy hadron colliders such as VHLC (Very Large Hadron Collider) with the energy of 28 TeV and SSC (Superconducting Super Collider) for two options with energies of 40 TeV and 100 TeV, respectively. The total cross sections of color sextet quark for three different machines are calculated and plotted versus its mass. The distributions of transverse momentum T p and invariant mass jj m of two final state jets are plotted for signals and backgrounds and analyzed the discovery limits of this resonance particle. The observation condition of color sextet quarks are performed by the number of signal events to the number of background events
Possible spin 3/2 quarks in neutrino reactions
International Nuclear Information System (INIS)
Aguiar, C.E.M.; Lopes, A.L.B.; Martins Simoes, J.A.; Leite Lopes, J.
1984-01-01
In this paper we discuss the hypothesis that quarks are composite objects and that excited states with spin 3/2 can be produced in neutrino reactions. Experimental consequences are analysed. The most relevant ones are scaling violations of a particular type and a consistent rate for same-sign dileptons
A consistent analysis for the quark condensate in QCD
International Nuclear Information System (INIS)
Huang Zheng; Huang Tao
1988-08-01
The dynamical symmetry breaking in QCD is analysed based on the vacuum condensates. A self-consistent equation for the quark condensate (φ φ) is derived. A nontrivial solution for (φ φ) ≠ 0 is given in terms of the QCD scale parameter A
Quark-diquark approximation of the three-quark structure of baryons in the quark confinement model
International Nuclear Information System (INIS)
Efimov, G.V.; Ivanov, M.A.; Lyubovitskij, V.E.
1990-01-01
Octet (1 + /2) and decuplet (3 + /2) of baryons as relativistic three-quark states are investigated in the quark confinement model (QCM), the relativistic quark model, based on some assumptions about hadronization and quark confinement. The quark-diquark approximation of the three-quark structure of baryons is proposed. In the framework of this approach the description of the main low-energy characteristics of baryons as magnetic moments, electromagnetic radii and form factors, ratio of axial and vector constants in semileptonic baryon octet decays, strong form factors and decay widths is given. The obtained results are in agreement with experimental data. 31 refs.; 4 figs.; 5 tabs
Composite quarks and their magnetic moments
International Nuclear Information System (INIS)
Parthasarathy, R.
1980-08-01
A composite quark model based on the symmetry group SU(10)sub(flavour) x SU(10)sub(colour) with the assumption of mass non-degenerate sub-quarks is considered. Magnetic moments of quarks and sub-quarks are obtained from the observed nucleon magnetic moments. Using these quark and sub-quark magnetic moments, a satisfactory agreement for the radiative decays of vector mesons (rho,ω) is obtained. The ratio of the masses of the sub-quarks constituting the u,d,s quarks are found to be Msub(p)/Msub(n) = 0.3953 and Msub(p)/Msub(lambda) = 0.596, indicating a mass hierarchy Msub(p) < Msub(n) < Msub(lambda) for the sub-quarks. (author)
Top quark production at the LHC
Gilles, Geoffrey; The ATLAS collaboration
2018-01-01
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, it gives us the unique opportunity to probe the properties of bare quarks at the Large Hadron Collider. This talk will present highlights of a few recent precision measurements of the top quark using 13 TeV and 8 TeV collision data: top-quark pair and single top production cross sections, including differential distributions and production in association with bosons, will be presented alongside top quark properties measurements. These measurements, including results using boosted top quarks, probe our understanding of top quark production in the TeV regime. Measurements of the top quark mass are also presented.
International Nuclear Information System (INIS)
Harari, H.
1977-01-01
The physics of quarks and leptons within the framework of gauge theories for the weak and electromagnetic interactions is reviewed. The Weinberg-Salam SU(2)xU(1) theory is used as a ''reference point'' but models based on larger gauge groups, especially SU(2)sub(L)xSU(2)sub(R)xU(1), are discussed. We distinguish among three ''Generations'' of fundamental fermions: The first generation (e - , νsub(e), u, d), the second generation (μ - , νsub(μ), c, s) and the third generation (tau - , νsub(tau), t, b). For each generation are discussed the classification of all fermions, the charged and neutral weak currents, possible right-handed currents, parity and CP-violation, fermion masses and Cabibbo-like angles and related problems. Theoretical ideas as well as experimental evidence, emphasizing open theoretical problems and possible experimental tests are reviewed, as well as the possibility of unifying the weak, electromagnetic and strong interactions in a grand unification scheme. The problems and their possible solutions are presented, generation by generation, but a brief subject-index (following the table of contents) enbales the interested reader to follow any specific topic throughout the three generations. (author)
AUTHOR|(SzGeCERN)655637
The measurement of prompt photon associated with a b jet in proton-proton interactions can provide us insight into the inner structure of proton. This is because precision of determination of parton distribution functions of b quark and gluon can be increased by such a measurement. The measurement of cross-section of prompt photon associated with a b jet (process $pp\\longrightarrow \\gamma + b + X$) at $\\sqrt{s}$= 8 TeV with the ATLAS detector is presented. Full 8 TeV dataset collected by ATLAS during the year 2012 was used in this analysis. Corresponding integrated luminosity is 20.3 $fb^{-1}$. Fiducial differential cross-section as a function of photon transverse momentum at particle level was extracted from data and compared with the prediction of leading order event generator Pythia 8. Cross-section extracted from data is normalised independently on the Monte Carlo prediction. Values of data distribution lie above Monte Carlo values. The difference can be explained by presence of higher order effects not ...
The quark-hadron phase transition and primordial nucleosynthesis
Hogan, Craig J.
1987-01-01
After presenting the current view of the processes taking place during the cosmological transition from 'quark soup' to normal hadron matter, attention is given to what happens to cosmological nucleosynthesis in the presence of small-scale baryon inhomogeneities. The QCD phase transition is among the plausible sources of this inhomogeneity. It is concluded that the formation of primordial 'quark nuggets' and other cold exotica requires very low entropy regions at the outset, and that even the more modest nonlinearities perturbing nucleosynthesis probably require some ingredient in addition to a quiescent, mildly supercooled transition.
Charm and strange quark contributions to the proton structure
Energy Technology Data Exchange (ETDEWEB)
Torokoff, K
1999-02-01
The possibility to have charm and strange quarks as quantum mechanical fluctuations in the proton wave function is investigated based on a model for non-perturbative QCD dynamics. Both hadron and parton basis are examined. A scheme for energy fluctuations is constructed and compared with explicit energy-momentum conservation. Resulting momentum distributions for charm and strange quarks in the proton are derived at the starting scale Q{sub 0} for the perturbative QCD evolution. Kinematical constraints are found to be important when comparing to the `intrinsic charm` model 20 refs, 30 figs, 9 tabs
Charm and strange quark contributions to the proton structure
International Nuclear Information System (INIS)
Torokoff, K.
1999-02-01
The possibility to have charm and strange quarks as quantum mechanical fluctuations in the proton wave function is investigated based on a model for non-perturbative QCD dynamics. Both hadron and parton basis are examined. A scheme for energy fluctuations is constructed and compared with explicit energy-momentum conservation. Resulting momentum distributions for charm and strange quarks in the proton are derived at the starting scale Q 0 for the perturbative QCD evolution. Kinematical constraints are found to be important when comparing to the 'intrinsic charm' model
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
Parton distributions and EMC ratios of the 6Li nucleus in the constituent quark exchange model
Modarres, M.; Hadian, A.
2017-10-01
While the constituent quark model (CQM), in which the quarks are assumed to be the complex objects, is used to calculate the parton distribution functions of the iso-scalar lithium-6 (6Li) nucleus, the u-d constituent quark distribution functions of the 6Li nucleus are evaluated from the valence quark exchange formalism (VQEF) for the A = 6 iso-scalar system. After computing the valence quark, sea quark, and gluon distribution functions in the constituent quark exchange model (CQEM, i.e., CQM +VQEF), the nucleus structure function is calculated for the 6Li nucleus at the leading order (LO) and the next-to-leading-order (NLO) levels to extract the European muon collaboration (EMC) ratio, at different hard scales, using the standard Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGALP) evolution equations. The outcomes are compared with those of our previous works and the available NMC experimental data, and various physical points are discussed. It is observed that the present EMC ratios are considerably improved compared with those of our previous works, in which only the valence quark distributions were considered to calculate the EMC ratio, and are closer to the NMC data. Finally, it is concluded that at a given appropriate hard scale, the LO approximation may be enough for calculating the nucleus EMC ratio.
A new kind of bottom quark factory
International Nuclear Information System (INIS)
Mtingwa, S.K.; Strikman, M.; AN SSSR, Leningrad
1991-01-01
We describe a novel method of producing large numbers of B mesons containing bottom quarks. It is known that one should analyze at least 10 9 B meson decays to elucidate the physics of CP violation and rare B decay modes. Using the ultra high energy electron beams from the future generation of electron linear colliders, we Compton backscatter low energy laser beams off these electron beams. From this process, we produce hot photons having energy hundreds of GeV. Upon scattering these hot photons onto stationary targets, we show that it is possible to photoproduce and measure the necessary 10 9 B mesons per year. 24 refs., 4 figs
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.)
The Ways of Four-Quark Hadrons
CERN. Geneva
2014-01-01
Ten years after the discovery of the X(3872) we can assert that a number of exotic four-quark hadrons with hidden charm and beauty have been discovered, the most recent, Z(3900), found by BES in 2013, being among the top-striking ones. However, ten years have not been enough to dispel the controversy about their inner structure, with two body hadron molecules and compact multiquark states being the withstanding antipodal models. In this seminar I will review the status of the field, presenting both the experimental facts and the theoretical pictures attempting to interpret them.
Heavy-Quark Associated Production with One Hard Photon at Hadron Colliders
Energy Technology Data Exchange (ETDEWEB)
Hartanto, Heribertus Bayu [Florida State Univ., Tallahassee, FL (United States)
2013-01-01
We present the calculation of heavy-quark associated production with a hard photon at hadron colliders, namely $pp(p\\bar p) → Q\\bar Q +X$γ (for $Q=t,b$), at Next-to-Leading Order (NLO) in Quantum Chromodynamics (QCD). We study the impact of NLO QCD corrections on the total cross section and several differential distributions at both the Tevatron and the Large Hadron Collider (LHC). For $t\\bar t$γ production we observe a sizeable reduction of the renormalization and factorization scale dependence when the NLO QCD corrections are included, while for $b\\bar b$γ production a considerable scale dependence still persists at NLO in QCD. This is consistent with what emerges in similar processes involving $b$ quarks and vector bosons and we explain its origin in detail. For $b\\bar b$γ production we study both the case in which at least one $b$ jet and the case in which at least two $b$ jets are observed. We perform the $b\\bar b$γ calculation using the Four Flavor Number Scheme (4FNS) and compare the case where at least one $b$ jet is observed with the corresponding results from the Five Flavor Number Scheme (5FNS) calculation. Finally we compare our results for $p\\bar p →+b+X$γ with the Tevatron data.
The proton electromagnetic form factor F2 and quark orbital angular ...
Indian Academy of Sciences (India)
Protein; electromagnetic form factors; perturbative QCD; quark orbital angular momentum. ... Failures of the ASD approach to correctly predict ex- perimental ... The success of the formalism is the correct prediction of the Q2 scaling behavior of ...
Inclusive production of large-p/sub T/ protons and quark-quark elastic scattering
International Nuclear Information System (INIS)
Chen, C.K.
1978-01-01
A proton-formation process in combination with hard quark-quark scattering is capable of explaining the observed large-p/sub T/ single-proton inclusive production data. This model implies that the inclusive production of two large-p/sub T/ protons at opposite directions is dominated by large-angle elastic scattering of two up quarks, and becomes an ideal place to study elastic quark-quark scattering. This two-proton inclusive production process is also ideal for the study of the spin structure of quark-quark elastic scattering, so the assumptions of pure vector-type quark-quark interaction and of colored quarks can be checked empirically. The consistency of applying the quark-elastic-scattering idea to large-angle elastic proton-proton scattering and to the inclusive production of large-p/sub T/ protons is also demonstrated
Strange Quark Matter Status and Prospects
Sandweiss, J.
2004-01-01
The existence of quark states with more than three quarks is allowed in QCD. The stability of such quark matter states has been studied with lattice QCD and phenomenological bag models, but is not well constrained by theory. The addition of strange quarks to the system allows the quarks to be in lower energy states despite the additional mass penalty. There is additional stability from reduced Coulomb repulsion. SQM is expected to have a low Z/A. Stable or metastable massive multiquark states contain u, d, and s quarks.
Searches for new heavy quarks in ATLAS
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.
Nucleon form factors, generalized parton distributions and quark angular momentum
Energy Technology Data Exchange (ETDEWEB)
Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kroll, Peter [Bergische Univ., Wuppertal (Germany). Fachbereich Physik; Regensburg Univ. (Germany). Institut fuer Theoretische Physik
2013-02-15
We extract the individual contributions from u and d quarks to the Dirac and Pauli form factors of the proton, after a critical examination of the available measurements of electromagnetic nucleon form factors. From this data we determine generalized parton distributions for valence quarks, assuming a particular form for their functional dependence. The result allows us to study various aspects of nucleon structure in the valence region. In particular, we evaluate Ji's sum rule and estimate the total angular momentum carried by valence quarks at the scale {mu}=2 GeV to be J{sup u}{sub v}=0.230{sup +0.009}{sub -0.024} and J{sup d}{sub v}=-0.004{sup +0.010}{sub -0.016}.
Nucleon form factors, generalized parton distributions and quark angular momentum
International Nuclear Information System (INIS)
Diehl, Markus; Kroll, Peter; Regensburg Univ.
2013-02-01
We extract the individual contributions from u and d quarks to the Dirac and Pauli form factors of the proton, after a critical examination of the available measurements of electromagnetic nucleon form factors. From this data we determine generalized parton distributions for valence quarks, assuming a particular form for their functional dependence. The result allows us to study various aspects of nucleon structure in the valence region. In particular, we evaluate Ji's sum rule and estimate the total angular momentum carried by valence quarks at the scale μ=2 GeV to be J u v =0.230 +0.009 -0.024 and J d v =-0.004 +0.010 -0.016 .
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.
Huber, Stefan; Nuerk, Hans-Christoph; Reips, Ulf-Dietrich; Soltanlou, Mojtaba
2017-12-23
Symbolic magnitude comparison is one of the most well-studied cognitive processes in research on numerical cognition. However, while the cognitive mechanisms of symbolic magnitude processing have been intensively studied, previous studies have paid less attention to individual differences influencing symbolic magnitude comparison. Employing a two-digit number comparison task in an online setting, we replicated previous effects, including the distance effect, the unit-decade compatibility effect, and the effect of cognitive control on the adaptation to filler items, in a large-scale study in 452 adults. Additionally, we observed that the most influential individual differences were participants' first language, time spent playing computer games and gender, followed by reported alcohol consumption, age and mathematical ability. Participants who used a first language with a left-to-right reading/writing direction were faster than those who read and wrote in the right-to-left direction. Reported playing time for computer games was correlated with faster reaction times. Female participants showed slower reaction times and a larger unit-decade compatibility effect than male participants. Participants who reported never consuming alcohol showed overall slower response times than others. Older participants were slower, but more accurate. Finally, higher grades in mathematics were associated with faster reaction times. We conclude that typical experiments on numerical cognition that employ a keyboard as an input device can also be run in an online setting. Moreover, while individual differences have no influence on domain-specific magnitude processing-apart from age, which increases the decade distance effect-they generally influence performance on a two-digit number comparison task.
Nuclear matter from effective quark-quark interaction.
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.
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.)
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
Wohrer, Adrien; Machens, Christian K
2015-03-01
All of our perceptual experiences arise from the activity of neural populations. Here we study the formation of such percepts under the assumption that they emerge from a linear readout, i.e., a weighted sum of the neurons' firing rates. We show that this assumption constrains the trial-to-trial covariance structure of neural activities and animal behavior. The predicted covariance structure depends on the readout parameters, and in particular on the temporal integration window w and typical number of neurons K used in the formation of the percept. Using these predictions, we show how to infer the readout parameters from joint measurements of a subject's behavior and neural activities. We consider three such scenarios: (1) recordings from the complete neural population, (2) recordings of neuronal sub-ensembles whose size exceeds K, and (3) recordings of neuronal sub-ensembles that are smaller than K. Using theoretical arguments and artificially generated data, we show that the first two scenarios allow us to recover the typical spatial and temporal scales of the readout. In the third scenario, we show that the readout parameters can only be recovered by making additional assumptions about the structure of the full population activity. Our work provides the first thorough interpretation of (feed-forward) percept formation from a population of sensory neurons. We discuss applications to experimental recordings in classic sensory decision-making tasks, which will hopefully provide new insights into the nature of perceptual integration.
Flavor Physics in the Quark Sector
Energy Technology Data Exchange (ETDEWEB)
Antonelli, Mario; /Frascati; Asner, David Mark; /Carleton U.; Bauer, Daniel Adams; /Imperial Coll., London; Becher, Thomas G.; /Fermilab; Beneke, M.; /Aachen, Tech. Hochsch.; Bevan, Adrian John; /Queen Mary, U. of London; Blanke, Monika; /Munich, Tech. U. /Munich, Max Planck Inst.; Bloise, C.; /Frascati; Bona, Marcella; /CERN; Bondar, Alexander E.; /Novosibirsk, IYF; Bozzi, Concezio; /INFN, Ferrara; Brod, Joachim; /Karlsruhe U.; Buras, Andrzej J.; /Munich, Tech. U.; Cabibbo, N.; /INFN, Rome /Rome U.; Carbone, A.; /INFN, Bologna; Cavoto, Gianluca; /INFN, Rome; Cirigliano, Vincenzo; /Los Alamos; Ciuchini, Marco; /INFN, Rome; Coleman, Jonathon P.; /SLAC; Cronin-Hennessy, Daniel P.; /Minnesota U.; Dalseno, J.P.; /KEK, Tsukuba /Glasgow U. /Queen Mary, U. of London /Freiburg U. /Charles U. /Pisa U. /Vienna, OAW /Imperial Coll., London /Bergen U. /INFN, Rome /Rome U. /Munich, Tech. U. /INFN, Rome /Rome U. /Southampton U. /INFN, Rome /Nara Women' s U. /Florida U. /INFN, Turin /Turin U. /Edinburgh U. /Warwick U. /INFN, Rome /Rome U. /Massachusetts U., Amherst /KEK, Tsukuba /Bern U. /CERN /Munich, Tech. U. /Mainz U., Inst. Phys. /Wayne State U. /Munich, Max Planck Inst. /CERN /Frascati /Brookhaven /Mainz U., Inst. Kernphys. /Munich, Tech. U. /Siegen U. /Imperial Coll., London /Victoria U. /KEK, Tsukuba /Fermilab /Washington U., St. Louis /Frascati /Warwick U. /Indian Inst. Tech., Madras /Melbourne U. /Princeton U. /Beijing, Inst. High Energy Phys. /INFN, Rome /INFN, Rome3 /Fermilab /SLAC /York U., Canada /Brookhaven /UC, Irvine /INFN, Rome /Rome U. /Valencia U., IFIC /INFN, Padua /Padua U. /Munich, Max Planck Inst. /Barcelona U. /Warwick U. /Tata Inst. /Frascati /Mainz U., Inst. Phys. /Vienna U. /KEK, Tsukuba /Orsay, LPT /Frascati /Munich, Tech. U. /Brookhaven /Bern U. /CERN /Mainz U., Inst. Phys. /Wayne State U. /Valencia U., IFIC /CERN /Kentucky U. /Oxford U. /Iowa State U. /Bristol U. /INFN, Rome /Rutherford /CERN /Orsay, LAL /Glasgow U. /INFN, Padua /Queen Mary, U. of London /Texas U. /LPHE, Lausanne /Fermilab /UC, Santa Cruz /Vienna, OAW /Cincinnati U. /Frascati /Orsay, LAL /Ohio State U. /Purdue U. /Novosibirsk, IYF /Frascati /INFN, Rome /Padua U. /INFN, Rome /Bern U. /Karlsruhe U. /Brookhaven /CERN /Paris U., VI-VII /Zurich, ETH /Pisa U. /Frascati /Oxford U. /Orsay, LAL /INFN, Rome2 /INFN, Rome /INFN, Rome3 /Princeton U. /Fermilab /Queen' s U., Kingston /KEK, Tsukuba /Melbourne U. /Brookhaven /Indiana U. /INFN, Rome /Rome U. /Pisa U. /Mainz U., Inst. Phys. /Karlsruhe U. /Oxford U. /Cambridge U., DAMTP /Edinburgh U. /CERN
2010-08-26
In the past decade, one of the major challenges of particle physics has been to gain an in-depth understanding of the role of quark flavor. In this time frame, measurements and the theoretical interpretation of their results have advanced tremendously. A much broader understanding of flavor particles has been achieved, apart from their masses and quantum numbers, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions. Among the most interesting phenomena of flavor physics is the violation of the CP symmetry that has been subtle and difficult to explore. In the past, observations of CP violation were confined to neutral K mesons, but since the early 1990s, a large number of CP-violating processes have been studied in detail in neutral B mesons. In parallel, measurements of the couplings of the heavy quarks and the dynamics for their decays in large samples of K,D, and B mesons have been greatly improved in accuracy and the results are being used as probes in the search for deviations from the Standard Model. In the near future, there will be a transition from the current to a new generation of experiments, thus a review of the status of quark flavor physics is timely. This report is the result of the work of the physicists attending the 5th CKM workshop, hosted by the University of Rome 'La Sapienza', September 9-13, 2008. It summarizes the results of the current generation of experiments that is about to be completed and it confronts these results with the theoretical understanding of the field which has greatly improved in the past decade.
Spin effects in high energy quark-quark scattering
International Nuclear Information System (INIS)
Goloskokov, S.V.; Selyugin, O.V.
1993-01-01
The spin amplitudes in high-energy quark-quark scattering at /t/>1 GeV 2 are analyzed. It is shown that the gluon contributions in the QCDα s 3 order lead to the spin-flip amplitude growing as s. This means the existence of the spin-flip part in pomeron exchange. The resulting T f is about few per cent of the spin-non-flip contribution. The factorization of the large-distance and high-energy effects in the spin-flip amplitude is obtained. 13 refs.; 2 figs.; 1 tab
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
Analytical Formulae linking Quark Confinement and Chiral Symmetry Breaking
International Nuclear Information System (INIS)
Doi, Takahiro M.; Redlich, Krzysztof; Sasaki, Chihiro; Suganuma, Hideo
2016-01-01
Dirac spectrum representations of the Polyakov loop fluctuations are derived on the temporally odd-number lattice, where the temporal length is odd with the periodic boundary condition. We investigate the Polyakov loop fluctuations based on these analytical relations. It is semi-analytically and numerically found that the low-lying Dirac eigenmodes have little contribution to the Polyakov loop fluctuations, which are sensitive probe for the quark deconfinement. Our results suggest no direct one-to-one corresponding between quark confinement and chiral symmetry breaking in QCD
Covariant introduction of quark spin into the dual resonance model
International Nuclear Information System (INIS)
Iroshnikov, G.S.
1979-01-01
A very simple method of insertion of a quark spin into the dual resonance model of hadron interaction is proposed. The method is suitable for amplitudes with an arbitrary number of particles. The amplitude of interaction of real particles is presented as a product of contribution of oscillatory excitations in the (q anti q) system and of a spin factor. The latter is equal to the trace of the product of the external particle wave functions constructed from structural quarks and satisfying the relativistic Bargman-Wigner equations. Two examples of calculating the meson interaction amplitudes are presented
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
International Nuclear Information System (INIS)
Gizhko, Andrii
2016-06-01
Three different, but related topics are the subject of this thesis, performed in the context of the ZEUS and CMS groups at DESY. The first measurement of the MS beauty-quark mass m b (m b ) at an electron-proton collider is presented. The measurement is based on a QCD analysis of beauty production cross sections in deep inelastic (DIS) ep scattering measured by ZEUS at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The measured value of the running beauty-quark mass in the MS scheme was found to be m b (m b )=4.07±0.14 (fit) +0.01 -0.07 (mod.) +0.05 -0.00 (param.) +0.08 -0.05 ( theo.) GeV, which is in good agreement with the world average Particle Data Group value and previous measurements at electron-positron colliders. It is also found to be consistent with the expected running of m b (μ). A first measurement of the charm-quark mass m c (μ) running in the MS scheme is presented. The measurement is based on a QCD analysis of the published H1 and ZEUS combination of charm cross section measurements in DIS ep scattering at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The running charm-quark mass m c (μ) was measured at different scales μ and is presented in a charm-quark mass running plot with a comparison to the world average Particle Data Group m c (m c ) evolved to higher scales. The running is found to be consistent with the expectations from QCD. The uncertainties of the theoretical predictions for Higgs production in association with beauty-quarks originating from the beauty-quark mass were studied and reduced for massive and massless QCD calculations. The beauty-quark mass measurement m b (m b ) was used to decrease the variation of the beauty-quark mass to 0.17 GeV. It was shown that the uncertainty from the beauty-quark mass m b (m b ) in the case of massive calculations for Hb anti b production at LHC can be reduced to 2%. This makes it negligible compared to other
Energy Technology Data Exchange (ETDEWEB)
Gizhko, Andrii
2016-06-15
Three different, but related topics are the subject of this thesis, performed in the context of the ZEUS and CMS groups at DESY. The first measurement of the MS beauty-quark mass m{sub b}(m{sub b}) at an electron-proton collider is presented. The measurement is based on a QCD analysis of beauty production cross sections in deep inelastic (DIS) ep scattering measured by ZEUS at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The measured value of the running beauty-quark mass in the MS scheme was found to be m{sub b}(m{sub b})=4.07±0.14 (fit){sup +0.01}{sub -0.07}(mod.){sup +0.05}{sub -0.00}(param.){sup +0.08}{sub -0.05}( theo.) GeV, which is in good agreement with the world average Particle Data Group value and previous measurements at electron-positron colliders. It is also found to be consistent with the expected running of m{sub b}(μ). A first measurement of the charm-quark mass m{sub c}(μ) running in the MS scheme is presented. The measurement is based on a QCD analysis of the published H1 and ZEUS combination of charm cross section measurements in DIS ep scattering at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The running charm-quark mass m{sub c}(μ) was measured at different scales μ and is presented in a charm-quark mass running plot with a comparison to the world average Particle Data Group m{sub c}(m{sub c}) evolved to higher scales. The running is found to be consistent with the expectations from QCD. The uncertainties of the theoretical predictions for Higgs production in association with beauty-quarks originating from the beauty-quark mass were studied and reduced for massive and massless QCD calculations. The beauty-quark mass measurement m{sub b}(m{sub b}) was used to decrease the variation of the beauty-quark mass to 0.17 GeV. It was shown that the uncertainty from the beauty-quark mass m{sub b}(m{sub b}) in the case of massive calculations for Hb anti b
Fundamental quark, lepton correspondence and dynamics with weak decay interactions
International Nuclear Information System (INIS)
Van der Spuy, E.
1977-10-01
A nonlinear fermion-field equation of motion and its (in principle) exact solutions, making use of the previously developed technique of infinite component free spinor fields, are discussed. It is shown to be essential for the existence of the solutions to introduce the isosymmetry breaking mechanism by coupling the isospin polarization of the domain of the universe of such particle fields to the field isospin. The essential trigger for the isosymmetry breaking mechanism is the existence of the electromagnetic interaction and the photon fields, carrying an infinite range isospin polarization change in the domain. A quartet of proton, neutron, lambda and charmed quark field solutions, with their respective characteristic Regge trajectories and primary isospin quantum numbers, and a quartet of lepton fields electron neutrino, electron, muon, muon nutrino, are shown to emerge naturally. The equations of motion of the quark and lepton propagators are deduced. The complicated charge nature of the quarks and the need for quark confinement is discussed and a correspondence principle is established between the quark and lepton field solutions. The correspondence is such that the dynamics of the leptons on their own appears to be compatible with quantum electrodynamics on the one hand, and on the other hand permits a natural GIM-Cabibbo weak decay interaction with a Cibibbo angle equal to the domain isospin polarization-change phase angle
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.)
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 p-antip annihilation in the quark model
International Nuclear Information System (INIS)
Niskanen, J.A.
1988-05-01
After a concise review of the N-antiN annihilation in the quark rearrangement and 3 P 0 annihilation models, preliminary results are given for the case with an additional term where a q-antiq pair with the gluon quantum number 3 S 1
Some spectroscopic problems in the bag theory of quark confinement
International Nuclear Information System (INIS)
Jaffe, R.L.
1976-04-01
In addition to conventional mesons and baryons, the bag model predicts the existence of several classes of unusual hadrons. The spectroscopy of two classes of unconventional hadrons is discussed: first are the Q 2 antiQ 2 mesons; second are Q 3 baryons or QantiQ mesons with quantum numbers forbidden by the nonrelativistic quark model
Sub-color and leptoquark-quark symmetry
International Nuclear Information System (INIS)
Nakamura, Fumihiko
1982-01-01
On the basis of leptoquark-quark symmetry, we propose possible models, in which leptons and gauge bosons are constructed is SU(2) symmetry. In one of the cases, the subcolor is introduced as the quantum number of the leptoquark. Then the possibility of baryon decay is discussed. (author)
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.)
The QCD phase transition with 2, 3, and 4 flavors of dynamical quarks
International Nuclear Information System (INIS)
Christ, N.H.
1991-01-01
Recent results from the 256-node Columbia machine are presented on 16 3 xN t lattices for N t = 4 and 6 using Kogut-Susskind fermions with quark masses ranging between 0.01 and 1.0 lattice units. It is argued that for four flavors the region for small quark mass where the transition is first order shrinks more rapidly than suggested by naive scaling gas N t increases from 4 to 6. For N t = 4 and three degenerate flavors of quarks the transition remains first order at m = 0.025 however it is weaker than for four flavors. For 2 flavors no first order signal is seen even when the quark mass decreased to 0.01. Finally, the location and nature of the transition as the strange quark mass is varied (interpolating between the case of 2 and 3 degenerate flavors) is discussed. (orig.)
Top quark mass measurement and color effects at the LHC
International Nuclear Information System (INIS)
Kovalchuk, Nataliia
2018-04-01
The top quark, the heaviest fundamental particle discovered to date, is one of the most peculiar particles that were discovered so far. It plays a crucial role in consistency checks of the Standard Model and in searches for new physics, e.g., supersymmetry, composite Higgs, and many other exotic models. In this thesis, an important property of the top quark is measured: the mass. This analysis is based on the data recorded at a center-of-mass energy of 13 TeV in 2016 with the CMS detector at the CERN LHC, and corresponds to an integrated luminosity of 35.9 fb -1 . The mass of the top quark is measured using the top quark pair event candidate, which corresponds to events with one muon or electron and at least four jets. The corresponding decay products are used in a kinematic fit to perform the jet quark assignment, increase the fraction of correctly reconstructed top quarks and to improve the mass resolution. Using the ideogram method the top quark mass is measured simultaneously with the jet scale factor (JSF), constrained by the jets arising from the W boson decay. The estimated result is calibrated with samples simulated with a next-to-leading order matrix element generator matched to the parton shower. The top quark mass is measured to be m t =172.25±0.08 (stat+JSF)±0.62 (syst) GeV. The results are tested for possible kinematic dependence by performing measurements of the top quark mass in different phase space regions. The residual data-to-simulation calibration of the energy of the jets is also estimated from dijet events with data collected at center-of-mass energy of 13 TeV in 2015 with the CMS detector corresponding to an integrated luminosity of 2.1 fb -1 . The corrections are performed using selected back-to-back dijet events by the MPF and dijet balance methods and are found to differ from unity by less then 3% in the barrel region and up to 17% in the endcap and forward regions of the detector. This result was used in the top mass measurement
Dynamical quark and gluon condensates from a modified perturbative QCD
International Nuclear Information System (INIS)
Cabo Montes de Oca, A.; Martinez Pedrera, D.
2004-12-01
As it was suggested by previous works on a modified perturbation expansion for QCD, the possibility for the generation of large quark condensates in the massless version of the theory is explored. For this purpose, it is firstly presented a way to well define the Feynman diagrams at any number of loops by just employing dimensional regularization. After that, the calculated zero and one loop corrections to the effective potential indicate a strong instability of the system under the generation of quark condensates even in the absence of the gluon one. The quark condensate dependence of particular two loop terms does not modify the instability picture arising at one loop. The results suggest a possible mechanism for a sort of Top Condensate Model to be a dynamically fixed effective action for massless QCD. The inability of lattice calculations in detecting this possibility could be related to the current limitations in treating the fermion determinants. (author)
Quark distributions in nuclear matter and the EMC effect
Energy Technology Data Exchange (ETDEWEB)
Mineo, H.; Bentz, W. E-mail: bentz@keyaki.cc.u-tokai.ac.jp; Ishii, N.; Thomas, A.W.; Yazaki, K
2004-05-03
Quark light cone momentum distributions in nuclear matter and the structure function of a bound nucleon are investigated in the framework of the Nambu-Jona-Lasinio model. This framework describes the nucleon as a relativistic quark-diquark state, and the nuclear matter equation of state by using the mean field approximation. The scalar and vector mean fields in the nuclear medium couple to the quarks in the nucleon and their effect on the spin independent nuclear structure function is investigated in detail. Special emphasis is placed on the important effect of the vector mean field and on a formulation which guarantees the validity of the number and momentum sum rules from the outset.
Pomeron-Quark Coupling from Charge Conjugation Invariance
International Nuclear Information System (INIS)
Zhou Lijuan; Wu Qing; Ma Weixing; Gu Yunting
2006-01-01
Based on the charge conjugation invariance and the vacuum property of the Pomeron, we point out that the commonly used vector vertex of the Pomeron coupling to quark is incorrect since it contradicts with the Pomeron property. We also claim that the soft Pomeron could be a tensor glueball ξ(2230) with quantum numbers I G J PC = 0 + 2 ++ and total decay width Γ tot ≅100 MeV, which lies on the soft Pomeron trajectory α p = 1.08+0.20t. Therefore, the coupling vertex of the soft Pomeron to quark should be tensorial which is invariant under the charge conjugation and can explain why the inadequate vector coupling, γ μ , of the soft Pomeron to quark is successful in dealing with Pomeron physics.
Measuring the sea quark polarization
International Nuclear Information System (INIS)
Makdisi, Y.
1993-01-01
Spin is a fundamental degree of freedom and measuring the spin structure functions of the nucleon should be a basic endeavor for hadron physics. Polarization experiments have been the domain of fixed target experiments. Over the years large transverse asymmetries have been observed where the prevailing QCD theories predicted little or no asymmetries, and conversely the latest deep inelastic scattering experiments of polarized leptons from polarized targets point to the possibility that little of the nucleon spin is carried by the valence quarks. The possibility of colliding high luminosity polarized proton beams in the Brookhaven Relativistic Heavy Ion Collider (RHIC) provides a great opportunity to extend these studies and systematically probe the spin dependent parton distributions specially to those reactions that are inaccessible to current experiments. This presentation focuses on the measurement of sea quark and possibly the strange quark polarization utilizing the approved RHIC detectors
Waves in magnetized quark matter
Fogaça, D. A.; Sanches, S. M.; Navarra, F. S.
2018-05-01
We study wave propagation in a non-relativistic cold quark-gluon plasma immersed in a constant magnetic field. Starting from the Euler equation we derive linear wave equations and investigate their stability and causality. We use a generic form for the equation of state, the EOS derived from the MIT bag model and also a variant of the this model which includes gluon degrees of freedom. The results of this analysis may be relevant for perturbations propagating through the quark matter phase in the core of compact stars and also for perturbations propagating in the low temperature quark-gluon plasma formed in low energy heavy ion collisions, to be carried out at FAIR and NICA.
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
Quark matter brings heavy ions to Oakland
International Nuclear Information System (INIS)
Klein, Spencer; Nystrand, Joakim
2004-01-01
The Quark Matter 2004 conference, held in Oakland, California, in January, provided participants with evidence for the elusive quark-gluon plasma. Spencer Klein and Joakim Nystrand describe the highlights of the meeting
On the Coulomb gauge quark propagator
International Nuclear Information System (INIS)
Kloker, M.; Alkofer, R.; Krassnigg, A.; Krenn, R.
2006-01-01
Full text: A solution of the quark Dyson-Schwinger equation including transverse gluons is presented. The corresponding retardation effects in the quark propagator are discussed. Especially, their effects on confinement properties and dynamical mass generation are described. (author)
International Nuclear Information System (INIS)
Rho, M.
1981-01-01
Quantum chromodynamics is believed to be candidate theory for the strong interactions and contains as its ingredients spinor quark fields and vector gluons, none of which can perhaps be ever liberated and detected in laboratories. A nucleus consists of nucleons bound by nuclear force which are however separately observable and which seem to preserve their identities even under extreme conditions. An intriguing question is: when compressed to high densities or heated to high temperature, at what point does a nuclear matter cease to be describable in terms of nucleon and meson degrees of freedom, but become a plasma of quarks and gluons; and how does this transition occur. This is not an idle question. If quarks and gluons are never to be observed isolated, then it may be that at low energies (or at low densities) they are not the right variables to do physics with. Instead hadrons must be. On the other hand, asymptotic freedom - the unique property of non-abelian gauge theories to which QCD belongs that quark-gluon and gluon-gluon interactions get weaker at short distances - tells us that at some large matter density the matter must necessarily be in the form of quark gas interacting only weakly. This means that a change in degrees of freedom must take place. We would like to know where this occurs and how. In this talk, I would like to address to this question by discussing first the large success we have had in understanding the role that mesons play in finite nuclei and nuclear matter and then attempting to correlate nucleon and meson degrees of freedom to quark-gluon degrees of freedom. In my opinion we are now at a stage where we feel fairly confident in our understanding of nucleon-meson structure of nuclei and nuclear matter and any further progress in deeper understanding of nuclear dynamics - and strong interactions - must come from QCD or its effective version, bags or strings. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hirschbuehl, Dominic [Univ. of Karlsruhe (Germany)
2005-12-23
In 1995 the heaviest elementary particle, top quark, was discovered at the Tevatron collider in top-antitop quark pair production. Since the top quark mass is of the same order as the electroweak symmetry breaking scale, measurements of the properties of the top quark like mass, charge, spin or the production mechanism, offer a good opportunity to test the Standard Model at such high energies. Top quarks at the Tevatron are predominantly pair-produced through light quark-antiquark annihilation. Higher order perturbative QCD calculations predict a sizeable asymmetry between the number of top quarks and antitop quarks produced in forward direction. This asymmetry is induced through radiative corrections. A measurement of the asymmetry can check the perturbative QCD predictions. Due to the high mass of the top quark, nearly the mass of a gold nucleus, the life time of the top quark is much shorter than the hadronization time-scale. This means that the top quark decays before it has a chance to form a bound state. The Standard Model predicts that the top quark decays in nearly 100% of the cases into a W boson and a b quark via a charge-current weak interaction. The measurement of the W boson helicity probes the V-A structure of the weak interaction and differences to the expectation would give evidence for new physics. Until the start of the Large Hadron Collider at CERN, the Tevatron is the only experiment where top quarks can be directly produced and their properties be measured. The Tevatron reaches a center-of-mass energy of 1.96 TeV in proton antiproton collisions. The data used in this analysis were taken in Run II of the Tevatron with the Collider Detector at Fermilab (CDF) in the years 2001-2004 and represent an integrated luminosity of 319 pb{sup -1}. The thesis is organized in the following way: In the first chapter a short overview of the Standard Model is given. The theoretical aspects of the top quark decay are described with particular emphasis on the
Bengtson, Barbara J.
2013-01-01
Understanding the linear relationship of numbers is essential for doing practical and abstract mathematics throughout education and everyday life. There is evidence that number line activities increase learners' number sense, improving the linearity of mental number line representations (Siegler & Ramani, 2009). Mental representations of…
Quark degrees of freedom in compact stars
Energy Technology Data Exchange (ETDEWEB)
Marranghello, G.F.; Vasconcellos, C.A.Z. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica. Dept. de Fisica; Hadjimichef, D. [Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica. Dept. de Fisica
2001-07-01
Nuclear matter may show a phase transition at high densities, where quarks and gluons are set free, forming a so called quark-gluon plasma. At the same range of densities, neutron stars are formed. In this work we have grouped both ideas in the study of the quark-gluon plasma formation inside compact stars, here treated as pure neutron star, hybrid star and pure quark matter star. (author)
Quark degrees of freedom in compact stars
International Nuclear Information System (INIS)
Marranghello, G.F.; Vasconcellos, C.A.Z.; Hadjimichef, D.
2001-01-01
Nuclear matter may show a phase transition at high densities, where quarks and gluons are set free, forming a so called quark-gluon plasma. At the same range of densities, neutron stars are formed. In this work we have grouped both ideas in the study of the quark-gluon plasma formation inside compact stars, here treated as pure neutron star, hybrid star and pure quark matter star. (author)
The weak conversion rate in quark matter
International Nuclear Information System (INIS)
Heiselberg, H.
1992-01-01
The weak conversion rate of strange to down quarks, s + u ↔ u + d, is calculated analytically for degenerate u, d and s quark matter to leading orders in temperature and deviations from chemical equilibrium. The rate is applied to burning of neutron matter into quark matter, to evaporation from quark nuggets in the early universe, for estimating the lifetime of strangelets, and to pulsar glitches
Top quark production at the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Varnes, Erich W.; /Arizona U.
2010-09-01
The Fermilab Tevatron has, until recently, been the only accelerator with sufficient energy to produce top quarks. The CDF and D0 experiments have collected large samples of top quarks. We report on recent top quark production measurements of the single top and t{bar t} production cross sections, as well as studies of the t{bar t} invariant mass distribution and a search for highly boosted top quarks.
Free-quark phases in dense stars
Energy Technology Data Exchange (ETDEWEB)
Keister, B D; Kisslinger, L S [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics
1976-08-30
The possibility is examined that superdense matter can undergo a transition to a phase of free quarks within models which assume that the quark confinement potential is screened at high densities. The results imply that a phase of pure quarks of this type is unlikely to be found in stable stellar systems although they do not preclude the possible existence of a transition region which contains quarks and neutrons in equilibrium at the center of neutron stars.
Triplicity of hadrons, quarks and subquarks
International Nuclear Information System (INIS)
Terazawa, Hidezumi.
1989-11-01
Triplicity of hadrons, quarks and subquarks asserting that a certain physical quantity such as the weak current is taken equally well as either one of a composite operator of hadrons, that of quarks and that of subquarks is proposed. Among other things, the weak mixing angle, the quark mixing matrix and the mass sum rules for quarks and leptons are revisited, reinterpreted and discussed in detail in triplicity. (author)
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.)
Pion electromagnetic polarizabilities and quarks
International Nuclear Information System (INIS)
Llanta, E.; Tarrach, R.
1980-01-01
The electric and magnetic polarizabilities of the neutral and charged pion are calculated in a coloured quark field theory at the one-loop level. The theory has as free parameter the quark mass but our results do not depend on it. We have found that the electric polarizabilities are αsub(π+-) = -0.04 α/m 3 sub(π), αsub(π 0 ) = -0.4 α/m 3 sub(π). These values are compared with calculations in other models and some comments are made about the polarizability sum rules. (orig.)
International Nuclear Information System (INIS)
Rho, M.
1983-11-01
The issue as to whether or not quarks will manifest themselves explicitly in nuclear processes is discussed in the light of the recently discovered topological structure of the baryon. Due to the leakage of the baryon charge from a confinement region (bag) into a meson-cloud region, there emerges a sort of topological equivalence principle which renders physically equivalent the description in terms of Goldstone meson fields alone (the Skyrmion) and the description in terms of a bag (confining quarks) surrounded by a meson cloud (the chiral bag model). How this new structure will modify our understanding of the nucleon and the nucleus is examined
The unconfined quarks and gluons
International Nuclear Information System (INIS)
Abdus Salam
1977-01-01
The consequences of the lepton-hadron gauge unification hypothesis with unconfined quarks and gluons being the hall-mark are discussed. Quark and gluon decays into leptons are shown to provide a new source of multileptonic production in NN, νN and μN collisions. A theorem is stated and proved which highlights the differences between the dynamics of gauge versus non-gauge 1 - particles. Empirical manifestations of gauge coloured mesons are discussed. The question of exact confinement or not is concluded to be in the end an empirical one and must be settled in the laboratory
Quarks and gluons in the phase diagram of quantum chromodynamics
Energy Technology Data Exchange (ETDEWEB)
Welzbacher, Christian Andreas
2016-07-14
In this dissertation we study the phase diagram of strongly interacting matter by approaching the theory of quantum chromodynamics in the functional approach of Dyson-Schwinger equations. With these quantum (field) equations of motions we calculate the non-perturbative quark propagator within the Matsubara formalism. We built up on previous works and extend the so-called truncation scheme, which is necessary to render the infinite tower of Dyson-Schwinger equations finite and study phase transitions of chiral symmetry and the confinement/deconfinement transition. In the first part of this thesis we discuss general aspects of quantum chromodynamics and introduce the Dyson-Schwinger equations in general and present the quark Dyson-Schwinger equation together with its counterpart for the gluon. The Bethe-Salpeter equation is introduced which is necessary to perform two-body bound state calculations. A view on the phase diagram of quantum chromodynamics is given, including the discussion of order parameter for chiral symmetry and confinement. Here we also discuss the dependence of the phase structure on the masses of the quarks. In the following we present the truncation and our results for an unquenched N{sub f} = 2+1 calculation and compare it to previous studies. We highlight some complementary details for the quark and gluon propagator and discus the resulting phase diagram, which is in agreement with previous work. Results for an equivalent of the Columbia plot and the critical surface are discussed. A systematically improved truncation, where the charm quark as a dynamical quark flavour is added, will be presented in Ch. 4. An important aspect in this investigation is the proper adjustment of the scales. This is done by matching vacuum properties of the relevant pseudoscalar mesons separately for N{sub f} = 2+1 and N f = 2+1+1 via a solution of the Bethe-Salpeter equation. A comparison of the resulting N{sub f} = 2+1 and N{sub f} = 2+1+1 phase diagram indicates
Flavor Physics in the Quark Sector
Antonelli, Mario; Bauer, Daniel Adams; Becher, Thomas G.; Beneke, M.; Bevan, Adrian John; Blanke, Monika; Bloise, C.; Bona, Marcella; Bondar, Alexander E.; Bozzi, Concezio; Brod, Joachim; Buras, Andrzej J.; Cabibbo, N.; Carbone, A.; Cavoto, Gianluca; Cirigliano, Vincenzo; Ciuchini, Marco; Coleman, Jonathon P.; Cronin-Hennessy, Daniel P.; Dalseno, J.P.; Davies, C.H.; Di Lodovico, Francesca; Dingfelder, Jochen C.; Dolezal, Zdenek; Donati, Simone; Dungel, W.; Egede, Ulrik; Eigen, Gerald; Faccini, Riccardo; Feldmann, Thorsten; Ferroni, Fernando; Flynn, Jonathan M.; Franco, Enrico; Fujikawa, M.; Furic, Ivan K.; Gambino, Paolo; Gardi, E.; Gershon, Timothy John; Giagu, Stefano; Golowich, Eugene; Goto, Toru; Greub, C.; Grojean, Christophe; Guadagnoli, Diego; Haisch, U.A.; Harr, Robert Francis; Hoang, Andre H.; Hurth, Tobias; Isidori, Gino; Jaffe, D.E.; Juttner, Andreas; Jager, Sebastian; Khodjamirian, Alexander; Koppenburg, Patrick Stefan; Kowalewski, Robert V.; Krokovny, P.; Kronfeld, Andreas Samuel; Laiho, J.; Lanfranchi, G.; Latham, Thomas Edward; Libby, James F.; Limosani, A.; Lopes Pegna, David; Lu, Cai-Dian; Lubicz, Vittorio; Lunghi, Enrico; Luth, Vera G.; Maltman, K.; Marciano, William Joseph; Martin, Emilie Claire Mutsumi; Martinelli, Guido; Martinez-Vidal, Fernando; Masiero, A.; Mateu, V.; Mescia, Federico; Mohanty, Gagan Bihari; Moulson, Matthew; Neubert, Matthias; Neufeld, Helmut; Nishida, Shohei; Offen, Nils; Palutan, M.; Paradisi, Paride; Parsa, Z.; Passemar, Emilie; Patel, M.; Pecjak, B.D.; Petrov, Alexey A.; Pich, Antonio; Pierini, Maurizio; Plaster, Brad; Powell, Brian Alfred; Prell, Soeren Andre; Rademaker, J.; Rescigno, Marco; Ricciardi, Stefania; Robbe, Patrick; Rodrigues, E.; Rotondo, Marcello; Sacco, Roberto; Schilling, Christopher James; Schneider, Olivier; Scholz, Enno E.; Schumm, Bruce Andrew; Schwanda, C.; Schwartz, Alan Jay; Sciascia, Barbara; Serrano, Justine; Shigemitsu, J.; Shipsey, Ian P.J.; Sibidanov, A.L.; Silvestrini, Luca; Simonetto, Franco; Simula, Silvano; Smith, Christopher; Soni, A.; Sonnenschein, Lars; Sordini, Viola; Sozzi, Marco S.; Spadaro, Tommaso; Spradlin, Patrick Michael; Stocchi, Achille; Tantalo, Nazario; Tarantino, Cecilia; Telnov, Alexandre V.; Tonelli, Diego; Towner, I.S.; Trabelsi, K.; Urquijo, Phillip; Van de Water, R.S.; Van Kooten, Richard J.; Virto, Javier; Volpi, Guido; Wanke, R.; Westhoff, Susanne; Wilkinson, G.; Wingate, Matthew Bowen; Xie, Y.; Zupan, Jure
2010-01-01
One of the major challenges of particle physics has been to gain an in-depth understanding of the role of quark flavor and measurements and theoretical interpretations of their results have advanced tremendously: apart from masses and quantum numbers of flavor particles, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions. Among the most interesting phenomena of flavor physics is the violation of the CP symmetry that has been subtle and difficult to explore. Till early 1990s observations of CP violation were confined to neutral $K$ mesons, but since then a large number of CP-violating processes have been studied in detail in neutral $B$ mesons. In parallel, measurements of the couplings of the heavy quarks and the dynamics for their decays in large samples of $K, D$, and $B$ mesons have been greatly improved in accuracy and the results are being used as probes in the search for deviations from the Standard Model. In the near...
Bethe-Salpeter dynamics and the constituent mass concept for heavy quark mesons
International Nuclear Information System (INIS)
Souchlas, N.; Stratakis, D.
2010-01-01
The definition of a quark as heavy requires a comparison of its mass with the nonperturbative chiral symmetry breaking scale which is about 1 GeV (Λ χ ∼1 GeV) or with the scale Λ QCD ∼0.2 GeV that characterizes the distinction between perturbative and nonperturbative QCD. For quark masses significantly larger than these scales, nonperturbative dressing effects, or equivalently nonperturbative self-energy contributions, and relativistic effects are believed to be less important for physical observables. We explore the concept of a constituent mass for heavy quarks in the Dyson-Schwinger equations formalism, for light-heavy and heavy-heavy quark mesons by studying their masses and electroweak decay constants.
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.)
Simulating at realistic quark masses. Light quark masses
International Nuclear Information System (INIS)
Goeckeler, M.; Streuer, T.
2006-11-01
We present new results for light quark masses. The calculations are performed using two flavours of O(a) improved Wilson fermions. We have reached lattice spacings as small as a ∝0.07 fm and pion masses down to m π ∝340 MeV in our simulations. This gives us significantly better control on the chiral and continuum extrapolations. (orig.)
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.)
Quark fragmentation in e+e- collisions
International Nuclear Information System (INIS)
Oddone, P.
1984-12-01
This brief review of new results in quark and gluon fragmentation observed in e + e - collisions concentrates mostly on PEP results and, within PEP, mostly on TPC results. The new PETRA results have been reported at this conference by M. Davier. It is restricted to results on light quark fragmentation since the results on heavy quark fragmentation have been reported by J. Chapman
Planar quark diagrams and binary spin processes
International Nuclear Information System (INIS)
Grigoryan, A.A.; Ivanov, N.Ya.
1986-01-01
Contributions of planar diagrams to the binary scattering processes are analyzed. The analysis is based on the predictions of quark-gluon picture of strong interactions for the coupling of reggeons with quarks as well as on the SU(6)-classification of hadrons. The dependence of contributions of nonplanar corrections on spins and quark composition of interacting particles is discussed
Charm-quarks and new elementary particles
International Nuclear Information System (INIS)
Petersen, J.L.
1978-01-01
This is the first part of an extensive paper which discusses: the Nobel prize in physics 1976; discovery of the J/psi-particle; elementary particles and elementary building blocks; the four reciprocal effects; gauge theories; quark-antiquark reciprocal effects; the high-energy approximation; a simple quark-antiquark potential; and quark diagrams and the Zweig rule. (Auth.)
Variational approach to chiral quark models
Energy Technology Data Exchange (ETDEWEB)
Futami, Yasuhiko; Odajima, Yasuhiko; Suzuki, Akira
1987-03-01
A variational approach is applied to a chiral quark model to test the validity of the perturbative treatment of the pion-quark interaction based on the chiral symmetry principle. It is indispensably related to the chiral symmetry breaking radius if the pion-quark interaction can be regarded as a perturbation.
A variational approach to chiral quark models
International Nuclear Information System (INIS)
Futami, Yasuhiko; Odajima, Yasuhiko; Suzuki, Akira.
1987-01-01
A variational approach is applied to a chiral quark model to test the validity of the perturbative treatment of the pion-quark interaction based on the chiral symmetry principle. It is indispensably related to the chiral symmetry breaking radius if the pion-quark interaction can be regarded as a perturbation. (author)
Pole masses of quarks in dimensional reduction
International Nuclear Information System (INIS)
Avdeev, L.V.; Kalmykov, M.Yu.
1997-01-01
Pole masses of quarks in quantum chromodynamics are calculated to the two-loop order in the framework of the regularization by dimensional reduction. For the diagram with a light quark loop, the non-Euclidean asymptotic expansion is constructed with the external momentum on the mass shell of a heavy quark
The quark gluon plasma; Le plasma de quarks et de gluons
Energy Technology Data Exchange (ETDEWEB)
Granier de Cassagnac, R. [Ecole Polytechnique, Lab. Leprince-Ringuet, 91 - Palaiseau (France)
2010-05-15
The quark-gluon plasma (QGP) is a state of matter in which the universe was expected to be a few micro-seconds after the big-bang. Violent collisions of heavy ions are supposed to re-create this state in particle accelerators. Numerous signatures of this fugacious state have already been observed at the RHIC (relativistic heavy ion collider). The first evidence of the violence of collisions is the number of generated particles: about 6000 per collision, mostly hadrons. This figure seems high but in fact is less than theoretically expected and is the first sign of the formation of a QGP that saturates the density of gluons. Another sign, observed at the RHIC is the damping of the particle jets that are produced in the collision. This damping is consistent with the crossing of a medium whose density is so high that it can not be made of hadrons but of partons. In the RHIC experiments the collective behaviour of quarks and gluons shows that they are strongly interacting with one another. This fact supports the idea that the QGP is more a perfect liquid rather than an ideal gas in which quarks and gluons move freely. (A.C.)
Directory of Open Access Journals (Sweden)
TRIFINA, L.
2011-02-01
Full Text Available This paper analyzes the extrinsic information scaling coefficient influence on double-iterative decoding algorithm for space-time turbo codes with large number of antennas. The max-log-APP algorithm is used, scaling both the extrinsic information in the turbo decoder and the one used at the input of the interference-canceling block. Scaling coefficients of 0.7 or 0.75 lead to a 0.5 dB coding gain compared to the no-scaling case, for one or more iterations to cancel the spatial interferences.
Charge asymmetry ratio as a probe of quark flavour couplings of resonant particles at the LHC
International Nuclear Information System (INIS)
Kom, Chun-Hay; Stirling, W.J.
2011-01-01
We show how a precise knowledge of parton distribution functions, in particular those of the u and d quarks, can be used to constrain a certain class of New Physics models in which new heavy charged resonances couple to quarks and leptons. We illustrate the method by considering a left-right symmetric model with a W' from a SU(2) R gauge sector produced in quark-antiquark annihilation and decaying into a charged lepton and a heavy Majorana neutrino. We discuss a number of quark and lepton mixing scenarios, and simulate both signals and backgrounds in order to determine the size of the expected charge asymmetry. We show that various quark-W' mixing scenarios can indeed be constrained by charge asymmetry measurements at the LHC, particularly at √(s)=14 TeV. (orig.)
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.)
International Nuclear Information System (INIS)
Meyer, Joerg; Bonn U
2007-01-01
Elementary particle physics raises questions that are several thousand years old. What are the fundamental components of matter and how do they interact? These questions are linked to the question of what happened in the very first moments after the creation of the universe. Modern physics systematically tests nature to find answers to these and other fundamental questions. Precise theories are developed that describe various phenomena and at the same time are reduced to a few basic principals of nature. Simplification and reduction have always been guiding concepts of physics. The interplay between experimental data and theoretical descriptions led to the Standard Model of elementary particle physics. It summarizes the laws of nature and is one of most precise descriptions of nature achieved by mankind. Despite the great success of the Standard Model it is not the ultimate theory of everything. Models beyond the Standard Model try to unify all interactions in one grand unified theory. The number of free parameters is attempted to be reduced. Gravity is attempted to be incorporated. Extensions to the Standard Model like supersymmetry address the so-called hierarchy problem. Precision measurements are the key for searches of new particles and new physics. A powerful tool of experimental particle physics are particle accelerators. They provide tests of the Standard Model at smallest scales. New particles are produced and their properties are investigated. In 1995 the heaviest known elementary particle, called top quark, has been discovered at Fermilab. It differs from all other lighter quarks due to the high mass and very short lifetime. This makes the top quark special and an interesting object to be studied. A rich program of top physics at Fermilab investigates whether the top quark is really the particle as described by the Standard Model. The top quark mass is a free parameter of the theory that has been measured precisely. This thesis presents a precise
Energy Technology Data Exchange (ETDEWEB)
Meyer, Joerg [Univ. of Bonn (Germany)
2007-01-01
Elementary particle physics raises questions that are several thousand years old. What are the fundamental components of matter and how do they interact? These questions are linked to the question of what happened in the very first moments after the creation of the universe. Modern physics systematically tests nature to find answers to these and other fundamental questions. Precise theories are developed that describe various phenomena and at the same time are reduced to a few basic principals of nature. Simplification and reduction have always been guiding concepts of physics. The interplay between experimental data and theoretical descriptions led to the Standard Model of elementary particle physics. It summarizes the laws of nature and is one of most precise descriptions of nature achieved by mankind. Despite the great success of the Standard Model it is not the ultimate theory of everything. Models beyond the Standard Model try to unify all interactions in one grand unified theory. The number of free parameters is attempted to be reduced. Gravity is attempted to be incorporated. Extensions to the Standard Model like supersymmetry address the so-called hierarchy problem. Precision measurements are the key for searches of new particles and new physics. A powerful tool of experimental particle physics are particle accelerators. They provide tests of the Standard Model at smallest scales. New particles are produced and their properties are investigated. In 1995 the heaviest known elementary particle, called top quark, has been discovered at Fermilab. It differs from all other lighter quarks due to the high mass and very short lifetime. This makes the top quark special and an interesting object to be studied. A rich program of top physics at Fermilab investigates whether the top quark is really the particle as described by the Standard Model. The top quark mass is a free parameter of the theory that has been measured precisely. This thesis presents a precise
The hadron to quark/gluon transition
International Nuclear Information System (INIS)
Brown, G.E.; Bethe, H.A.; Pizzochero, P.M.
1991-01-01
In this paper we are concerned with the hadron to quark/gluon transition. We describe the equilibrium states of hadronic matter by a Hagedorn spectrum; introducing scaling masses, as dictated by the restoration of chiral invariance with increasing temperature, we show that in the chiral SU(2) f limit there is a maximum hadron temperature (T H ) max ≅ 128 MeV. Since the quark/gluon perturbative phase involves restoration of conformal invariance, we take the bag constant to be the conformal anomaly, i.e. the gluon condensate. The stability condition P QG > 0 for the pressure requires that there is a minimum temperature; we find (T QG ) min ≅ 172 MeV for SU(2) f . According to the simple Hagedorn model, there appears to be a region of temperature between (T H ) max and (T QG ) min in which no admissible equilibrium states exist. Since the two phases cannot exist at a common temperature, in this model there is no QCD phase transition. (orig.)
The calculation of multiquark hadrons by the quark model baryon, meson and multiquark states
International Nuclear Information System (INIS)
Takeuchi, Sachiko; Takizawa, Makoto; Yasui, Shigehiro
2011-01-01
The 1st new hadron summer school related with the new science field, 'the comprehensive research of new hadron states searched by variable flavor number scheme', was held on August 18-20, 2010. This report is one of the 'quark model' lectures. The chapter 1 describes following problems: 1. The background and the significance as a phenomenological theory of the constituent quark model. 2. The introduction of the quark model. 3. The summary of the properties of hadrons in which the quark model can apply to three quarks (qqq) and, one quark and antiquark (q - q) configurations, but is difficult to apply to some configurations. 4. A brief summary of exotic hadrons and recent problems. In chapter 2, the introduction and some exercises of the stochastic variational method are reported as a technique of solving spatial part of multiquark states. In the chapter 3, spins and color parts in multiquark states are calculated. The group theory is applied to calculate the eigenvalues of the Casimir operators of SU(2), SU(3) and SU(6). In the problems of being unable to apply Casimir operators, the direct matrix diagonalization method, m-scheme, is employed for interacting quarks and for the interaction involving quark mass. To find the attractive interaction in tetraquark (QQqq-bar) state is given as an exercise problem. (Y. Kazumata)
Fragmentation of quarks and gluons
International Nuclear Information System (INIS)
Soeding, P.
1983-10-01
The author presents a review about quark and gluon jets. He describes the particle contents of the different types of jets. Finally he considers the hadronization mechanism with special regards to three-jet events in e + e - annihilation and hadronization in nuclear matter. (HSI)
Quarks, history of a discovery
International Nuclear Information System (INIS)
Husson, D.
2000-01-01
This book gives a presentation of quarks and stresses on the historical aspects of the studies that led to their discovery. The 'aesthetical' motivations of the scientists in their research are explained with only a minimum of mathematical concepts. (J.S.)
Phase space quark counting rule
International Nuclear Information System (INIS)
Wei-gin, C.; Lo, S.
1980-01-01
A simple quark counting rule based on phase space consideration suggested before is used to fit all 39 recent experimental data points on inclusive reactions. Parameter free relations are found to agree with experiments. Excellent detail fits are obtained for 11 inclusive reactions