Extraction of clan model parameters from multiplicity distributions measured in pp collisions at LHC energies

Abstract

This paper presents the variation of clan model parameters nc and N̄ with energy for p-p collisions at √s = 900 and 2360 GeV using ALICE and CMS as the detectors. The data for multiplicity distribution was reported by the ALICE and CMS collaborations. The values of n̄c and N̄ are evaluated from the NBD fit parameters n̄ and k. Hegyi [Phys. Lett. B 274, 214 (1992)] suggested an alternative method for determination of clan model parameters from void probability. A comparison of values obtained from the two methods is also done. A close agreement of values obtained from the two methods was observed for 546 GeV p-p̄ collisions. However for LHC data the agreement is not very well. Void probability overestimates the value of n̄c and underestimates the value of N̄ compared to that obtained from NBD. n̄c is found to increase with energy for both ALICE and CMS data. Contrary to the observation at lower energies that N̄ does not depend on energy, it is found to vary with energy. The variation of N̄ with energy is more prominent for CMS data. The results are discussed in detail. For CMS data, comparison of the results with the 7000 GeV data is also shown. © 2011 World Scientific Publishing Company.