相关论文: About flavor, spin and color
We study the structure of QCD at very large baryon density for an arbitrary number of flavors $N_f$. We provide evidence that for any number of flavors larger than $N_f=2$ chiral symmetry remains broken at asymptotically large chemical…
We suggest that breaking of SU(3) flavor symmetry mainly resides in the baryon wave--functions while the charge operators have no (or only small) explicit symmetry breaking components. We utilize the collective coordinate approach to chiral…
We extend Zirnbauer's color-flavor transformation in the fermionic sector to the case of the special unitary group. The transformation allows a certain integral over SU(N_c) color matrices to be transformed into an integral over flavor…
I review various aspects of chiral symmetry and its spontaneous breaking on null planes, including the interesting manner in which Goldstone's theorem is realized and the constraints that chiral symmetry imposes on the null-plane…
These lectures discuss the question of whether a key feature is seen in hadron spectroscopy--the near degeneracy of hadrons with different parity and/or spin. It has been conjectured that this is due to an effective restoration of chiral…
We test a candidate for a four-dimensional C-function. This is done by considering all asymptotically free, vectorlike gauge theories with N_f flavors and fermions in arbitrary representations of any simple Lie group. Assuming spontaneous…
Effects of soft breaking in N=1 supersymmetric gauge theories are studied. For N_f < N_c, we include the dynamics of the non-perturbative superpotential and use the original (s)quark and gauge fields. For N_f > N_c +1, we formulate the…
We investigate QCD with a large number of massless flavors with the aid of renormalization group flow equations. We determine the critical number of flavors separating the phases with and without chiral symmetry breaking in SU(Nc) gauge…
Behind the observed pattern of lepton flavor mixing is a partial or approximate mu-tau flavor symmetry --- a milestone on our road to the true origin of neutrino masses and flavor structures. In this review article we first describe the…
New relations between the quark spin-flavor contents of the nucleon and axial weak coupling constants are obtained in the chiral quark model with both SU(3) and U(1)-breaking effects. Using the nonsinglet spin combinations, $\Delta_3$ and…
We present an update of our ongoing study of the SU(2) gauge theory with one flavor of Dirac fermion in the adjoint representation. Compared to our previous results we now have data at larger lattice volumes, smaller values of the fermion…
We illustrate why color deconfines when chiral symmetry is restored in gauge theories with quarks in the fundamental representation, and while these transitions do not need to coincide when quarks are in the adjoint representation,…
It is shown that the principal pattern in baryon spectroscopy, which is associated with the flavor-spin dependent hyperfine interaction, is due to the spontaneous breaking of chiral symmetry in QCD and persists in the chiral limit. All…
Chiral symmetry breaking patterns are investigated in the U_L(n)xU_R(n) meson model. It is shown that new classes of minima of the effective potential belonging to the center of the Lie algebra exist for arbitrary flavor number n. The true…
It is well established that the $SU(P)_L$ gauge symmetry for $P\geq 3$ can address the question of fermion generation number due to the anomaly cancellation, but it neither commutes nor closes algebraically with electric and…
We analyse - within the hamiltonian formalism with staggered fermions - the patterns of chiral symmetry breaking for the strongly coupled Schwinger and $U({\cal N}_c)$-color `t Hooft models with one and two flavor of fermions. Using the…
The magnetic and transition magnetic moments of the ground-state baryons are computed in heavy baryon chiral perturbation theory in the large-$N_c$ limit, where N_c is the number of colors. SU(3) symmetry breaking is systematically studied…
The concept of (global) gauge symmetry breaking plays an important role in many areas of physics. Since the corresponding symmetry is a gauge symmetry, its breaking is actually gauge-dependent. Thus, it is possible to design gauges which…
In light of the observation of a relatively large $\theta^{}_{13}$, one has to consider breaking the $\mu$-$\tau$ symmetry properly which would otherwise result in a vanishing $\theta^{}_{13}$ (as well as $\theta^{}_{23} = \pi/4$).…
We examine flavor SU(3) breaking effects on meson-baryon scattering amplitudes in the chiral unitary model. It turns out that the SU(3) breaking, which appears in the leading quark mass term in the chiral expansion, can not explain the…