Pion fluctuation and its multiplicity dependence in ultrarelativistic nuclear collisions

This paper studies the multiplicity dependence of the fluctuation pattern of pions produced for 16O–AgBr interactions at 60 A GeV and 32S–AgBr interactions at 200 A GeV. We divided the data for the pions produced into four sets depending on the number of shower tracks (ns). We investigated the fluctuation pattern of emitted pions corresponding to different sets in both η (pseudorapidity) and ϕ (azimuthal angle) space. The multiplicity dependence was studied with respect to parameters αq, Dq, multifractal specific heat c, and effective fluctuation strength αeff. The study clearly indicates that the fluctuation pattern depends on multiplicity both in pseudorapidity and azimuthal angle space for 16O initiated interactions. However, for 32S initiated interactions, no multiplicity dependence is evidenced by the data in azimuthal angle space. For both, the multiplicity dependence is not very strong and significant only at large average multiplicity. Multiplicity dependence was further studied in a small window around the central pseudorapidity, and we found that multiplicity dependence is more prominent in the central region. The multiplicity dependence of αeff is more pronounced in the case of 32S–AgBr interactions than in case of 16O–AgBr interactions. PACS Nos.: 25.75–q, 24.60 Ky