The light front analysis of pi^{ -} mesons in A_{ P} (He, C, Mg, O) + A_{ T} (Li,C, Ne, Mg,Cu,Pb) collisions is carried out. The phase space of secondary pions is naturally divided into two parts in one of which the thermal equilibration assumption seems to be in a good agreement with data. Corresponding temperatures are extracted and compared to the results of other experiments. The dependence of the average temperature T on (A_{ P}*A_{ T})^{ 1/2} is studied.
Categories: hep-ex