Neutral pion number fluctuations at high multiplicity in pp-interactions at 50 GeV

The results of E-190 experiment (project Thermalization) with 50 GeV pro- ton beam irradiation of SVD-2 setup are presented. MC simulation has shown the linear dependence of number of photons detected in electromagnetic calorimeter and the average number of neutral pions. Multiplicity distribution of neutral pion, N0, for total number of particles in the event, Ntot = Nch + N0, are obtained with corrections on the setup accep- tance, triggering and efficiency of the event reconstruction. The scaled variance of neutral pionfluctuations, ! = D/ , versus total multiplicity is measured. The fluctuations increase at Ntot > 18. According to quantum statistics models this behavior can indicate a pioncondensate formation in the high pionmultiplicity system. This effect has been observed for the first time.