Parity odd bubbles in hot QCD
Loading...
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
We consider the topological susceptibility for an SU(N) gauge theory in the limit of a large number of colors, $N \to \infty$. 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 $T=T_d$, is of second order. Then we argue that Witten's relation implies that the topological susceptibility vanishes in a calculable fashion at $T_d$. As noted by Witten, this implies that for sufficiently light quark masses, metastable states which act like regions of nonzero $θ$ --- parity odd bubbles --- can arise at temperatures just below $T_d$. Experimentally, parity odd bubbles have dramatic signatures: the $η'$ meson, and especially the $η$ meson, become light, and are copiously produced. Further, in parity odd bubbles, processes which are normally forbidden, such as $η\to π^0 π^0$, are allowed. The most direct way to detect parity violation is by measuring a parity odd global asymmetry for charged pions, which we define.
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
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