English

Parity odd bubbles in hot QCD

High Energy Physics - Phenomenology 2007-05-23 v1

Abstract

We consider the topological susceptibility for an SU(N) gauge theory in the limit of a large number of colors, NN \to \infty. At nonzero temperature, the behavior of the topological susceptibility depends upon the order of the deconfining phase transition. The most interesting possibility is if the deconfining transition, at T=TdT=T_d, is of second order. Then we argue that Witten's relation implies that the topological susceptibility vanishes in a calculable fashion at TdT_d. As noted by Witten, this implies that for sufficiently light quark masses, metastable states which act like regions of nonzero θ\theta --- parity odd bubbles --- can arise at temperatures just below TdT_d. Experimentally, parity odd bubbles have dramatic signatures: the η\eta' meson, and especially the η\eta meson, become light, and are copiously produced. Further, in parity odd bubbles, processes which are normally forbidden, such as ηπ0π0\eta \to \pi^0 \pi^0, are allowed. The most direct way to detect parity violation is by measuring a parity odd global asymmetry for charged pions, which we define.

Keywords

Cite

@article{arxiv.hep-ph/9808366,
  title  = {Parity odd bubbles in hot QCD},
  author = {D. Kharzeev and R. D. Pisarski and M. H. G. Tytgat},
  journal= {arXiv preprint arXiv:hep-ph/9808366},
  year   = {2007}
}

Comments

9 pages, LaTeX, requires sprocl.sty, to appear in the Proceedings of the 3rd workshop on "Continuous Advances in QCD", Minneapolis, 16-19 April, 1998