Measurement of event-by-event transverse momentum and multiplicity fluctuations using strongly intensive measures $Δ[P_T, N]$ and $Σ[P_T, N]$ in nucleus-nucleus collisions at the CERN Super Proton Synchrotron
nucl-ex
/ Authors
NA49 Collaboration, T. Anticic, B. Baatar, J. Bartke, H. Beck, L. Betev, H. Bialkowska, C. Blume, B. Boimska, J. Book
and 57 more authors
M. Botje, P. Buncic, P. Christakoglou, P. Chung, O. Chvala, J. Cramer, V. Eckardt, Z. Fodor, P. Foka, V. Friese, M. Gazdzicki, K. Grebieszkow, C. Hohne, K. Kadija, A. Karev, V. Kolesnikov, M. Kowalski, D. Kresan, A. Laszlo, R. Lacey, M. van Leeuwen, M. Mackowiak-Pawlowska, M. Makariev, A. Malakhov
/ Abstract
Results from the NA49 experiment at the CERN SPS are presented on event-by-event transverse momentum and multiplicity fluctuations of charged particles, produced at forward rapidities in central Pb+Pb interactions at beam momenta 20$A$, 30$A$, 40$A$, 80$A$, and 158$A$ GeV/c, as well as in systems of different size ($p+p$, C+C, Si+Si, and Pb+Pb) at 158$A$ GeV/c. This publication extends the previous NA49 measurements of the strongly intensive measure $Φ_{p_T}$ by a study of the recently proposed strongly intensive measures of fluctuations $Δ[P_T, N]$ and $Σ[P_T, N]$. In the explored kinematic region transverse momentum and multiplicity fluctuations show no significant energy dependence in the SPS energy range. However, a remarkable system size dependence is observed for both $Δ[P_T, N]$ and $Σ[P_T, N]$, with the largest values measured in peripheral Pb+Pb interactions. The results are compared with NA61/SHINE measurements in $p+p$ collisions, as well as with predictions of the UrQMD and EPOS models.