共查询到20条相似文献,搜索用时 46 毫秒
1.
A quark meson coupling model based on
SU(3)L×SU(3)R symmetry and scale invariance is proposed. The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to investigating the nuclear matter at finite
temperature and density. The effective
baryon masses, compression modulus and hyperon potentials are all reasonable.
The critical temperature of liquid-gas phase transition is also calculated
in this model. 相似文献
2.
The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiralfields are considered, the phase shifts of 1 So wave are obviously improved. 相似文献
3.
Introducing a finite chemical potential μ for the quark number density ψ°ψ, we study analytically the restoration of Π° chiral symmetry as μ is varied. In the strong coupling limit, the effective lagrangian for SU(N) gauge theories coupled to fermion fields in d dimensions is derived for all N. In the case of SU(2) we predict a second order chiral symmetry restoration phase transition, whereas for all N?3 the transition is first order. Predictions are given for the critical values of the chemical potential μ. 相似文献
4.
Zeitschrift für Physik C Particles and Fields - We discuss an effective Lagrangian model in which theU (1) chiral symmetry is restored above theSU (L) ?SU (L) chiral phase transition (L... 相似文献
5.
We investigate the composition and structure of neutron-, hybrid-, and quark stars within an effective QCD-motivated model of strong interaction. The hadronic phase is described within a novel chiral SU(3) model and the deconfined quark-gluon plasma phase is formulated within the bag model. The phase transition between these phases is treated as a first order transition having two conserved charges. 相似文献
6.
J. Kogut H. Matsuoka M. Stone H.W. Wyld S. Shenker J. Shigemitsu D.K. Sinclair 《Nuclear Physics B》1983,225(1):93-122
Chiral symmetry restoration in an environment rich in baryons is studied by computer simulation methods in SU(2) and SU(3) gauge theories in the quenched approximation. The basic theory of symmetry restoration as a function of chemical potential is illusstrated and the implementation of the ideas on a lattice is made explicit. A simple mean field model is presented to guide one's expectations. The second order conjugate-gradient iterative method and the pseudo-fermion Monte Carlo procedure are convergent methods of calculating the fermion propagator in an environment rich in baryons. Computer simulations of SU(3) gauge theory show an abrupt chiral symmetry restoring transition and the critical chemical potential and induced baryon density are estimated crudely. A smoother transition is observed for the color group SU(2). 相似文献
7.
用手征 SU( 3)夸克模型分析了 ( 0 s) 6组态的六夸克态能量 ,结果表明手征 SU( 3)介子场可以对某些多奇异数的态提供较强的吸引作用 .进一步用共振群方法研究了 ( ΩΩ) 0 + 及 ( ΩΞ) 1+ 等多奇异数系统 ,得到 ( ΩΩ) 0 是一个深度束缚的双重态. An analysis is made for the (0s) 6 six quark cluster states in the chiral SU (3) quark model. The results show that for some multistrangeness states the chiral SU (3) could offer more attraction. Further RGM dynamical calculation of the multistrangeness system (ΩΩ) 0+ and (ΩΞ) 1+ has been done. It shows that (ΩΩ) 0+ is a deeply bound state in the chiral SU (3) quark model. 相似文献
8.
The kaon cloud correction to the magnetic moments of the octet baryons that arises when chiral SU(2) × SU(2) symmetry is enlarged to SU(3) × SU(3) is calculated in the chiral bag model. The effect is considerably smaller than the pion cloud effect provided the bag radius is R ? 1 fm. We discuss the implications of this result on our ongoing attempt to incorporate chiral symmetry into the bag model of the nucleon and on the scale sizes associated with (nearly) massless quarks and massive quarks. 相似文献
9.
Philip Rau Jan Steinheimer Stefan Schramm Horst St?cker 《Central European Journal of Physics》2012,10(6):1302-1305
With an effective chiral flavour SU(3) model we show the effect of hadronic resonances on the QCD phase diagram. We state that varying the resonance couplings to the scalar and vector fields affects the order and location of the phase transition, the possible existence of a critical end point (CEP), and the thermodynamic properties. We present (strange) quark number susceptibilities at zero baryochemical potential and at three different points at the phase transition. Comparing results to lattice QCD, we state that reasonable large vector couplings limit the phase transition to a smooth crossover ruling out a CEP. 相似文献
10.
Christian S. Fischer Axel Maas Jens A. Müller 《The European Physical Journal C - Particles and Fields》2010,68(1-2):165-181
We study a gauge-invariant order parameter for deconfinement and the chiral condensate in SU(2) and SU(3) Yang–Mills theory in the vicinity of the deconfinement phase transition using the Landau gauge quark and gluon propagators. We determine the gluon propagator from lattice calculations and the quark propagator from its Dyson–Schwinger equation, using the gluon propagator as input. The critical temperature and a deconfinement order parameter are extracted from the gluon propagator and from the dependency of the quark propagator on the temporal boundary conditions. The chiral transition is determined using the quark condensate as order parameter. We investigate whether and how a difference in the chiral and deconfinement transition between SU(2) and SU(3) is manifest. 相似文献
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在手征SU(3)夸克模型和扩展的手征SU(3)夸克模型的框架下, 用变分的方法系统地研究了同位旋为0、1, 自旋宇称为0+、1+和2+的udss四夸克系统6个低组态的能量. 模型的参数取自以前的工作, 它能很好地描述核子-核子散射相移以及核子-超子散射截面. S道相互作用的参数由拟合K介子和K*介子的质量定出, 并且考虑了具有相同量子数的态之间的态混合效应. 结果表明, 同位旋为0且自旋宇称为1+的udss能量低于相应的K*K*,的阈能, 且该组态中KK*的成分相当小, 因此该组态的宽度可能较小, 可视为一个可能的四夸克态的候选者. 相似文献
14.
We present a study of Goldstone boson scattering based on the flavor SU(3) chiral Lagrangian formulated with vector mesons in the tensor field representation. A coupled-channel computation is confronted with the empirical s- and p-wave phase shifts, where good agreement with the data set is obtained up to about 1.2 GeV. There are two relevant free parameters only, the chiral limit value of the pion decay constant and the coupling constant characterizing the decay of the rho meson into a pair of pions. We apply a recently suggested approach that implements constraints from micro-causality and coupled-channel unitarity. Generalized potentials are obtained from the chiral Lagrangian and are expanded in terms of suitably constructed conformal variables. The partial-wave scattering amplitudes are defined as solutions of non-linear integral equations that are solved by means of an N/D ansatz. 相似文献
15.
The phase transition of the two-dimensional SU(2)⊗ SU(2) lattice chiral model has been studied by a variational cumulant expansion method. The internal energy and the specific heat are calculated to the 4th order correction and they are in good agreement with the Monte Carlo (MC) resdits. Except the behavior of the crossover region, similarities between this model and the four-dimensional SU(2) lattice gauge model are also discussed. 相似文献
16.
S. Hands I. Montvay L. Scorzato J. Skullerud 《The European Physical Journal C - Particles and Fields》2001,22(3):451-461
We study SU(2) lattice gauge theory at non-zero chemical potential with one staggered quark flavor in the adjoint representation.
In this model the fermion determinant, although real, can be both positive and negative. We have performed numerical simulations
using both hybrid Monte Carlo and two-step multibosonic algorithms, the latter being capable of exploring sectors with either
determinant sign. We find that the positive determinant sector behaves like a two-flavor theory, with the chiral condensate
rotating into a two-flavor diquark condensate for , implying a superfluid ground state. Good agreement is found with analytical predictions made using chiral perturbation theory.
In the ‘full’ model there is no sign of either onset of baryon density or diquark condensation for the range of chemical potentials
we have considered. The impact of the sign problem has prevented us from exploring the true onset transition and the mode
of diquark condensation, if any, for this model.
Received: 28 September 2001 / Published online: 23 November 2001 相似文献
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We consider corrections to the baryon mass spectrum when the u and the d quarks are massive, i.e. the pion acquires its physical mass. This breaks explicitely the SU(2) chiral symmetry of the chiral quark model. We also include the massive K- and η-mesons to examine the broken SU(3) and SU(3) × SU(3) symmetries. These small corrections do improve the mass spectrum. 相似文献
19.
R. Dashen 《Physics letters. [Part B]》1974,50(4):460-462
We show that in the non-linear σ-model, we have a phase transition when the isospin chemical potential is equal to the meson mass. This result is shown to be generally true in the SU(2)×SU(2) symmetry breaking model. 相似文献
20.
HUANGFei ZHANGZong-Ye YUYou-Wen 《理论物理通讯》2004,42(4):577-580
The isospin I = 0 and I = 1 kaon-nucleon S and P partial waves phase shifts have been studied in the chiral SU(3) quark model by solving a resonating group method equation. When the parameters of the chiral fields are taken in a reasonable region, the numerical results of S-wave are in good agreement with the experimental data, and the P-wave phase shifts can also be explained qualitatively by the calculation of only central force considered. 相似文献