Quark masses and chiral symmetry.
نویسنده
چکیده
I discuss the global structure of the strongly interacting gauge theory of quarks and gluons as a function of the quark masses and the CP violating parameter. I concentrate on whether a rst order phase transition occurs at = : I show why this is expected when multiple avors have a small degenerate mass. This transition can be removed by suucient avor-breaking. I speculate on the implications of this structure for Wilson's lattice fermions.
منابع مشابه
Chiral Symmetry in Matter *
Soft-pion theorems are used to show how chiral symmetry constrains the contributions of low-momentum pions to the quark condensate, the pion decay constant and hadron masses, all of which have been proposed as signals of partial restoration of chiral symmetry in matter. These have contributions of order T 2 for a pion gas or of order mπ for cold nuclear matter, which have different coefficients...
متن کاملPossible Pseudogap Phase in QCD
Thermal pion fluctuations, in principle, can completely disorder the phase of the quark condensate and thus restore chiral symmetry. If this happens before the quark condensate melts, strongly-interacting matter will be in the pseudogap state just above the chiral phase transition. The quark condensate does not vanish locally and quarks acquire constituent masses in the pseudogap phase, despite...
متن کاملDirect extraction of the chiral quark condensate and bounds on the light quark masses
We select sum rules from which one can extract directly reliable limits on the size of the chiral symmetry breaking light quark condensate 〈ψ̄ψ〉. Combined results from the nucleon and B∗-B mass-splitting sum rules give a result compatible with the standard value: 〈ψ̄ψ〉(1 GeV)≃ (−229 MeV), through the determinations of the quark-gluon mixed condensate. The vector form factor of the D → K∗lν semi-l...
متن کاملBaryon Masses in Lattice QCD with Exact Chiral Symmetry
We investigate the baryon mass spectrum in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with Wilson gauge action at β = 6.1 on the 20×40 lattice, we compute (point-to-point) quark propagators for 30 quark masses in the range 67 MeV ≤ mq ≤ 1790 MeV. For baryons only composed of strange and charm quarks, their masses are extracted directly from the time ...
متن کاملFoundations of the Constituent Quark Model
‘Constituent quarks’ means massive quarks, in contrast to the nearly massless u, d, s quarks of the QCD lagrangian. The dynamical or constituent masses appear owing to the spontaneous chiral symmetry breaking in QCD. A realistic mechanism of the chiral symmetry breaking is provided by instantons. Therefore, I review the present status of the QCD instanton vacuum, emphasizing the mechanism of ch...
متن کاملThe θ-Vacua and the Leutwyler–Smilga Scaling Regime
The partition function of QCD is studied in the Leutwyler–Smilga scaling regime for an arbitrary number of quark flavors and masses including the contributions from all winding numbers. For Nf = 2 and degenerate quark masses, the partition function becomes independent of the quark masses at θ = π and subsequently the scalar chiral condensate vanishes. There is a discontinuity at θ = π in the fi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review. D, Particles and fields
دوره 52 5 شماره
صفحات -
تاریخ انتشار 1995