共查询到20条相似文献,搜索用时 15 毫秒
1.
It is demonstrated that when quantum correlations are added, chiral Lagrangians need not generate strong many-body forces as they do in tree approximation. We suggest that a physically reasonable procedure is to adjust the σ-model parameters so as not to conflict with the current status of nuclear theory. As a consequence, the equilibrium density of abnormal states could be pushed up further, and the binding energy be considerably reduced. 相似文献
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Jan Smit 《Nuclear Physics B》1980,175(2):307-348
The strong chiral symmetry breaking in Wilson's lattice version of QCD is discussed and interpreted as a necessary manifestation of the triangle anomaly. At strong coupling the effective hamiltonian acting in the s-wave hadron sector is found to describe a generalized antiferromagnet which is analyzed with the expansion known in the theory of magnetism. Mesons emerge as spin waves: pseudoscalars as Nambu-Goldstone bosons, vectors as “dormant” Goldstone bosons. Current and dynamical quark masses are identified, such that mP2 ∫ m(cur), mv≈2[m(cur) + m(fyn)], and a fit to the particle spectrum gives m(dyn) = 390 MeV, mu,d(cur) = 5.4 MeV, ms(cur) = 140 MeV, mc(cur) = 1.07 GeV. Static baryons emerge with a mass mB = N[m(dyn) + m(cur)] + a contribution which is argued to vanish in the continuum limit. Vector and axial vector currents are defined on the lattice and studied at strong coupling. The relations , Zπ/Z? = 3.0 are found to agree with experiment. The resolution of the U(1) problem at strong coupling is discussed. 相似文献
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In hamiltonian lattice gauge theory, the fermion vacuum at lowest order in 1/g2 can be determined from degenerate perturbation theory plus mean field-spin wave techniques. Using compact QED as an example, we show that: (i) chiral symmetry is spontaneously broken; and (ii) . The pseudoscalar pseudoGoldstone particles—the “pions” of this abelian theory—correspond to antiferromagnetic spin wave excitations of the fermion vacuum. 相似文献
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I discuss the temperature dependence of quarkonium correlators calculated in lattice QCD. I show that the dominant source
of the temperature dependence comes from the zero-mode contribution, while the temperature dependence associated with the
melting of bound states is quite small. I study the zero-mode contribution quantitatively for various quark masses and show
that it is well described by a quasi-particle model with temperature-dependent heavy quark mass. As a byproduct, an estimate
of the medium dependence of the heavy-quark mass is obtained. 相似文献
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I. B. Pestov 《Physics of Atomic Nuclei》2011,74(7):1055-1061
Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself
spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field
(space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry
induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics.
Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction. 相似文献
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Chiral symmetry in nuclei 总被引:1,自引:0,他引:1
Effective field theory is considered to provide a highly useful framework for connecting nuclear physics with the symmetries and dynamics of the underlying theory of strong interactions, QCD. Of many issues that are of great current interest in this domain, I concentrate here on two: (1) A new class of ab initio calculations of observables in two-nucleon systems; (2) Attempts to extend chiral perturbation calculations to higher-order terms. 相似文献
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D. Atkinson P. W. Johnson M. Koopmans 《Zeitschrift fur Physik C Particles and Fields》1987,34(1):99-101
By applying bifurcation theory to a truncated Dyson-Schwinger equation for the quark propagator in massless QCD, we show that dynamical symmetry breaking occurs at a certain critical value of the coupling constant. Essential ingredients are (a) an effective dynamical mass for the gluon, and (b) a running coupling constant. 相似文献
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S. Narison 《Physics letters. [Part B]》1984,142(3):168-172
Using a spectral function sum rules approach, we derive some constraints among the Goldstone parameters, the lowest dimension vacuum condensates and the mass of the chiral matter superfield in supersymmetric QCD (SQCD). These relations are consistent with previous results on SQCD and complement them. 相似文献
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The contributions of the minimal chiral two-pion exchange nucleon-nucleon potential for some selected observables are studied by means of the variable phase method. We conclude that chiral symmetry is responsible for important cancellations, which are related to those occurring in pion-nucleon scattering. 相似文献
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The connection between chiral symmetry and supersymmetry is investigated in the context of a supersymmetric extension of the Nambu-Jona-Lasinio model. A supersymmetric gap equation is found and it is shown that no solution exists which breaks chiral symmetry. A simple physical argument for this phenomenon is given and possible implications for the dynamics of composite models are discussed. 相似文献
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An approach to baryons in the framework of the microscopic generalized Nambu-Jona-Lasinio chiral potential quark model is
considered and quite general arguments are given in favor of the effective restoration of the chiral symmetry in excited baryons.
The text was submitted by the authors in English. 相似文献
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T. DeGrand 《The European physical journal. Special topics》2007,152(1):1-27
Four lectures about chiral symmetry and dynamical fermions in QCD.
1) Chiral symmetry in continuum QCD with an eye toward lattice simulations. 2) Lattice fermions with exact chiral symmetry:
staggered fermions, fermions in
five dimensions, chiral fermions in four dimensions.
3) A typical lattice simulation from beginning to end: the simulation algorithm,
designing observables to measure some desired quantity, analyzing the data.
4) Recent lattice results relevant to chiral symmetry: a mini-review. 相似文献
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Dieter Gromes 《Physics letters. [Part B]》1982,115(6):482-486
We consider the influence of the gluon condensate in QCD on the energy levels of quarkonia, taking into account the x-dependence of 〈ω|:Gμva(x) Gaμv(0):|ω〉. The modification compared to earlier approaches which approxim ated the above vacuum expectation value by a constant is quite sizeable; for the b?b system we find that the effect can be essentially described in terms of a local potential. 相似文献
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Nirupam Dutta Surasree Mazumder 《The European Physical Journal C - Particles and Fields》2018,78(6):525
We demonstrate that spin flipping transitions occur between various quarkonium spin states due to transient magnetic field produced in non central heavy ion collisions (HICs). The inhomogeneous nature of the magnetic field results in non adiabatic evolution of (spin)states of quarkonia moving inside the transient magnetic environment. Our calculations explicitly show that the consideration of azimuthal inhomogeneity gives rise to dynamical mixing between different spin states owing to Majorana spin flipping. Notably, this effect of non-adiabaticity is novel and distinct from previously predicted mixing of the singlet and one of the triplet states of quarkonia in the presence of a static and homogeneous magnetic field. 相似文献
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T. Kojo 《Physics of Atomic Nuclei》2012,75(5):632-636
The 1/N c expansion classifies nuclearmatter, deconfined quark matter, and Quarkyonic matter in low temperature region. We investigate the realization of chiral symmetry in Quarkyonic matter by taking into account condensations of chiral particle-hole pairs. It is argued that chiral symmetry and parity are locally violated by the formation of chiral spirals, $\left\langle {\bar \psi exp\left( {2i\mu _q z\gamma ^0 \gamma ^z } \right)\psi } \right\rangle$ . An extension to multiple chiral spirals is also briefly discussed. 相似文献