par Tytgat, Michel 
Référence Physical review. D, Particles, fields, gravitation, and cosmology, 61, 11
Publication Publié, 2000
Référence Physical review. D, Particles, fields, gravitation, and cosmology, 61, 11
Publication Publié, 2000
Article révisé par les pairs
| Résumé : | We consider QCD at (Formula presented) with two, one and zero light flavors (Formula presented) using the Di Vecchia–Veneziano–Witten effective Lagrangian. For (Formula presented) we show that (Formula presented) is spontaneously broken at (Formula presented) for finite quark mass splittings, (Formula presented) In the (Formula presented) plane, there is a line of first order transitions at (Formula presented) with two critical end points, (Formula presented) We compute the tension of the domain walls that relate the two (Formula presented) violating vacua. For (Formula presented) the tension of the family of equivalent domain walls agrees with the expression derived by Smilga from chiral perturbation theory at next-to-leading order. For (Formula presented) (Formula presented) there is only one domain wall and a wall-some sphaleron at (Formula presented) At the critical points, (Formula presented) the domain wall fades away, (Formula presented) is restored and the transition becomes of second order. For (Formula presented) (Formula presented) is spontaneously broken only if the number of colors (Formula presented) is large and/or if the quark is sufficiently heavy. Taking the heavy quark limit (Formula presented) provides a simple derivation of the multibranch (Formula presented) dependence of the vacuum energy of large (Formula presented) pure Yang-Mills theory. In the large (Formula presented) limit, there are many quasistable vacua with a decay rate (Formula presented) © 2000 The American Physical Society. |
