Anomalous pion decay in effective QCD at finite temperature
Abstract
The width of the process π^{0} → γγ is calculated within effective QCD at finite temperature. We use two different effective models which describe chiral symmetry breaking and its restoration at finite temperature in SU(2)_{ƒ}: (i) an effective lagrangian with a nonlocal separable interaction kernel, (ii) A and BscaledNJL lagrangians which implement the scale anomaly of QCD. We calculate the temperature dependences of the quark and pion masses as well as of the pionparkantiquark coupling strength below and above the double quark mass threshold. At zero temperature we obtain a fairly good agreement with the experimental value for the decay width. The temperature dependence of the decay width is related to that of the pion mass. Γ_{π0 → γγ} is enhanced in the vicinity of the Mott temperature ( M_{π} = 2 m_{q}) for the nonlocal as well as for the Ascaled model and suppressed for the Bscaled model. We compare our results with the SU(2) NambuJonaLasinio model which is contained as a limiting case in our approach.
 Publication:

Nuclear Physics A
 Pub Date:
 February 1995
 DOI:
 10.1016/03759474(95)00304J
 Bibcode:
 1995NuPhA.592..561B