Olimov Kh.K., Lutpullaev S.L., Glagolev V.V., et al. Centrality dependences of soft and hard components of pt distributions of negative pions in 4He+12C collisions at 4.2AGeV/c.
The dependences of the shapes of transverse momentum distributions of the negative pions, produced in minimum bias 4He+12C collisions at a momentum of 4.2GeV/c per nucleon, on collision centrality and ﬁtting range of pt were analyzed systematically. To study the change in slopes (temperatures) of the pt spectra of π− with changing collision centrality and ﬁtting pt range, the pt spectra, extracted from the experimental data and quark–gluon string model (QGSM) calculations, were ﬁtted by the one-and two-temperature Hagedorn and Boltzmann functions. Fitting of the experimental pt distributions of π− in both the whole pt and pt =0.1–1.2GeV/c intervals required the two-temperature functions for adequate description of spectra, in agreement with the previous ﬁndings for diﬀerent sets of colliding nuclei and various energies. On the whole, the absolute values of the extracted temperatures were lower in case of ﬁtting range pt =0.1–0.7GeV/c as compared to the ﬁtting interval pt =0.1–1.2GeV/c. The one-temperature functions were suﬃcient for ﬁtting satisfactorily the experimental pt distributions of the negative pions in range pt =0.1–0.7GeV/c. In contrast to the experimental temperatures, the extracted QGSM temperatures were not sensitive to collision centrality and ﬁtting range of pt.