High pt charged-pion production in Pb-Au collisions at 158AGeV/c

TL;DR

This paper reports measurements of charged-pion transverse momentum spectra in Pb-Au collisions at 158 AGeV/c, revealing exponential spectra with a slight increase in inverse slope with collision centrality and a constant pi-/pi+ ratio.

Contribution

First measurement of charged-pion spectra at high pt in Pb-Au collisions at CERN SPS, showing exponential behavior and centrality dependence of inverse slope.

Findings

Exponential transverse momentum spectra with average inverse slope of 245 MeV/c.

Inverse slope increases by 2.4% with collision centrality.

Pi-/pi+ ratio remains constant at 1.028 across measured pt range.

Abstract

The CERES/Na45 experiment at CERN SPS measured transverse momentum spectra of charged-pions in the range 1<pt<4GeV/c near mid-rapidity in 158 AGeV/c Pb-Au collisions. The invariant transverse momentum spectra are exponential over the entire observed range. The average inverse slope is 245+/- 5MeV/c, it shows a 2.4% increase with centrality of the collision over the 35% most central fraction of the cross section. The pi-/pi+ ratio is constant at 1.028+/-0.005 over the pt interval measured.