Related papers: Light quarks masses and condensates in QCD
The light scalar meson spectrum is studied using the improved ladder QCD with the UA(1) breaking Kobayashi-Maskawa-'t Hooft interaction by solving the Schwinger-Dyson and Bethe-Salpeter equations. The dynamically generated…
Spontaneous chiral symmetry breaking, mesons and baryons are illustrated in the language of the Dirac theory. Various forces acting between quarks inside baryons are discussed. I explain why the naive quark models typically overestimate…
The light quark masses are determined using a new QCD Finite Energy Sum Rule (FESR) in the pseudoscalar channel. This FESR involves an integration kernel designed to reduce considerably the contribution of the (unmeasured) hadronic…
We probe effects of the partial chiral symmetry restoration to the mass of heavy-light mesons in a constituent quark model by changing the constituent quark mass of the light quark. Due to the competing effect between the quark mass and the…
It has recently been suggested \cite{Chang:2006bm} that a reliable and unambiguous definition of the non-perturbative massive quark condensate could be provided by considering a non positive-definite class of solutions to the Schwinger…
We present a quantitative analysis of chiral symmetry breaking in two-flavour continuum QCD in the quenched limit. The theory is set-up at perturbative momenta, where asymptotic freedom leads to precise results. The evolution of QCD towards…
We examine artifacts associated with the chiral symmetry breaking induced through the use of Wilson-Dirac fermions in lattice Monte Carlo computations. For light quark masses, the conventional quenched theory can not be defined using direct…
We explore a possible phase where chiral $SU(2)_L \times SU(2)_R$ symmetry is spontaneously broken while its center $Z_2$ symmetry remains unbroken and its consequence on thermal quantities. In this phase, chiral symmetry breaking is driven…
In the limit of vanishing up, down and strange quark masses, QCD exhibits a chiral symmetry. This symmetry is broken spontaneously to its vector subgroup, giving rise to Goldstone bosons. These acquire a small mass through the explicit…
The structure of the hadron spectrum is discussed in connection with the main phenomena of nonperturbative QCD: confinement and chiral symmetry breaking (CSB). For the higher part of the spectrum ($M \ge 2 GeV$) spin and chiral effects are…
Partially quenched chiral perturbation theory assumes that valence quarks propagating on gauge configurations prepared with sea quarks of different masses will form a chiral condensate as the valence quark mass goes to zero. I present a…
We discuss a random matrix theory that was originally constructed to describe two-color QCD at low density in the phase with a nonzero chiral condensate. With a particular choice of a parameter, the same random matrix theory also describes…
By means of unitarized Chiral Perturbation Theory it is possible to obtain a remarkable description of meson-meson scattering amplitudes up to 1.2 GeV, and generate poles associated to scalar and vector resonances. Since Chiral Perturbation…
Results for light quark masses obtained from lattice QCD simulations are compared and contrasted with other determinations. Relevance of these results to estimates of $\epsilon'/\epsilon$ is discussed.
Recently there have been proposals to understand features of QCD such as confinement and chiral symmetry breaking by considering supersymmetric versions of the theory with various patterns of soft breaking. In this note we recall that with…
I report on recent work done in collaboration with M. Knecht on patterns of spontaneous chiral symmetry breaking in the large-Nc limit of QCD-like theories, and with S. Peris and M. Perrottet concerning the question of matching long and…
We study the light scalar mesons in the QCD sum rule. We find that there are five independent scalar tetraquark currents in the local form, and we perform QCD sum rule analysis using both these currents and their combinations. Compared with…
I discuss the zero temperature phase diagram of QCD, as a function of baryon density and strange quark mass. The noteworthy points are that at sufficiently high density chiral symmetry is always restored, and at low strange quark mass there…
The surprising thing is that arising almost 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, the light scalar meson problem has become central in the nonperturbative quantum chromodynamics (QCD) for…
The electroweak symmetry breaking and origin of masses may be attributed to the breakdown of chiral symmetry due to a strong gauge dynamics. Among several candidates of such gauge systems, we focus on two-color QCD with $N_f=6$ massless…