共查询到20条相似文献,搜索用时 0 毫秒
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《Nuclear Physics B》1988,307(4):669-704
The meson Bethe-Salpeter wavefunction and density-density correlation function are calculated for SU(N) lattice gauge theory in two dimensions and shown to agree in detail with continuum weak coupling solutions. 相似文献
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Marco Bochicchio 《Few-Body Systems》2016,57(6):455-459
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The temporal pseudoscalar meson correlation function in a QCD plasma is investigated in a range of temperatures exceeding Tc and yet of experimental interest. Only the flavour-singlet channel is considered and the imaginary time formalism is employed for the finite temperature calculations. The behaviour of the meson spectral function and of the temporal correlator is first studied in the HTL approximation, where one replaces the free thermal quark propagators with the HTL resummed ones. This procedure satisfactory describes the soft fermionic modes, but its application to the propagation of hard quarks is not reliable. An improved version of the so-called NLA scheme, which allows a better treatment of the hard fermionic modes, is then proposed. The impact of the improved NLA on the pseudoscalar temporal correlator is investigated. 相似文献
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We discuss QCD with two light flavors at large baryon chemical potential micro. Color superconductivity leads to partial breaking of the color SU(3) group. We show that the infrared physics is governed by the gluodynamics of the remaining SU(2) group with an exponentially soft confinement scale Lambda(')(QCD) approximately Deltaexp[-a(mu)/(gDelta)], where Delta< mu is the superconducting gap, g is the strong coupling, and a = 2sqrt[2] pi/11. We estimate that, at moderate baryon densities, Lambda(')(QCD) is O(10 MeV) or smaller. The confinement radius increases exponentially with density, leading to "asymptotic deconfinement." The velocity of the SU(2) gluons is small due to the large dielectric constant of the medium. 相似文献
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Piotr Czerski 《Central European Journal of Physics》2012,10(2):342-348
Analytical results for the spatial dependence of the correlation functions for all meson excitations in perturbative Quantum
Chromodynamics, the lowest order, are calculated. The meson screening mass is obtained as a large distance limit of the correlation
function. Our analysis leads to a better understanding of the excitations of Quark Gluon Plasma at sufficiently large temperatures
and may be of relevance for future numerical calculations with fully interacting Quantum Chromodynamics. 相似文献
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We show that in very dense quark matter there must exist metastable domain walls where the axial U(1) phase of the color-superconducting condensate changes by 2pi. The decay rate of the domain walls is exponentially suppressed and we compute it semiclassically. We give an estimate of the critical chemical potential above which our analysis is under theoretical control. 相似文献
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WANG Rui CHEN Ying GONG Ming LIU Chuan LIU Yu-Bin LIU Zhao-Feng MA Jian-Ping MENG Xiang-Fei ZHANG Jian-Bo 《理论物理通讯》2015,63(5):559-564
Vector meson mass values are studied at finite chemical potential and temperature in lattice QCD with lattice size of 24 × 122× 6 using two flavors of staggered quarks. The investigation focuses on the change of the vector meson mass in the critical region close to T c with two different types of chemical potentials switched on: the isoscalar chemical potential μS and its isovector counterpart μV. It is found that the vector meson mass increases in the QGP phase with both chemical potentials and decreases with μS in the confinement phase. 相似文献
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本文讨论在背景场量子色动力学框架中的等时方程赝标介子解. 方程的积分核由微扰和非微扰贡献两部分组成.微拔部分是通常的单胶子交换图的贡献;非微扰部分的贡献来自于最低阶的夸克和胶子凝聚效应. 当输入合理的夸克质量参数和耦合常数时,可以得到与实验相符合的赝标介子谱. 相似文献
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We investigate the effects of an external magnetic field in the gap structure of a color superconductor with three massless quark flavors. Using an effective theory with four-fermion interactions, inspired by one-gluon exchange, we show that the long-range component B of the external magnetic field that penetrates the color-flavor locked phase modifies its gap structure, producing a new phase of lower symmetry. A main outcome of our study is that the B field tends to strengthen the gaps formed by Q-charged and Q-neutral quarks that coupled among themselves through tree-level vertices. These gaps are enhanced by the field-dependent density of states of the Q-charged quarks on the Fermi surface. Our considerations are relevant for the study of highly magnetized compact stars. 相似文献
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Based on the quark-gluon contents of nucleon and strongly believing that the force mediators, Pomeron and its counterpart in the conventional approach of Regge theory, for high energy diffractive process would be the tensor glueball and Odderonrespectively, we discuss photo-production of vector meson ø off the deuteron at energy less than 3 GeV in the QCD inspired model in which the quark gluon degrees of freedom and glueball, Odderon exchange are taken into account. A calculation isperformed for γ+D → ø+D, and the theoretical predictions of the differential cross section dσ γD/dt, are presented and compared with available experimental data. Our QCD inspired model reproduces data quite well in the whole range of the experimental measurements up to |t|≌ 0.4~GeV. Our results can be used toextract γn →øn data, which cannot be measured in experiment. 相似文献
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The leading-twist distribution amplitude for the longitudinal rho-meson was studied using QCD Sum Rules with nonlocal condensates and a spectral density which includes next-to-leading order radiative corrections. The obtained profile is compared with results from standard QCD sum rules, lattice QCD, holographic QCD, a light-front quark model, and the instanton liquid model. Preliminary estimates for the first two moments of the transverse ρ-meson distribution amplitude are also given. 相似文献
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We report on a lattice investigation of improved quenched Wilson fermions above and below the confinement-deconfinement phase
transition. Results on meson screening masses as well as spatial wave functions are presented. Moreover, the meson dispersion
relation is studied. Below the critical temperature we do not observe any significant temperature effect while above the data are consistent with a leading free quark behavior.
Received: 2 April 2001 / Published online: 8 June 2001 相似文献
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The masses of pseudoscalar and vector mesons and their radial excitations are measured in the quenched approximation to QCD by a 32nd-order numerical hopping-parameter expansion on a 164 lattice. Scaling behaviour, finite-size effects and the influence of statistics are studied. 相似文献