Simple parametrizations of light meson properties in hot or dense matter

Sophisticated calculations of the dynamics of relativistic heavy-ion collisions often need as input properties of light mesons in medium. In this context simple analytical expressions for these quantities which respect chiral symmetry and low-energy current algebra results are most desirable. In the present work we provide such simple expressions based on a bosonized version of the microscopic NJL model. We also study the pion lifetime in hot and dense matter showing that the ratio pi(pi(-) --> mu(-) + <(nu)over bar>(mu)/pi(pi(-) --> e(-) + <(nu)over bar>(e)) changes by a factor about three and thus carries a clear signature of the chiral phase transition. (C) 1997 Elsevier Science B.V.