Recent results from NA61/SHINE and NA49

TL;DR

This paper presents recent experimental results on particle spectra and fluctuations from NA61/SHINE and NA49 at CERN SPS, highlighting phase space effects and comparing different collision systems to understand underlying physics.

Contribution

It introduces new measurements of particle spectra and fluctuations, and offers a novel approach to analyze excitation functions in heavy-ion collisions.

Findings

Dependence of fluctuation results on phase space coverage.

Explanation of differences between NA49 and STAR measurements.

Insights into particle production mechanisms in p+p and Pb+Pb collisions.

Abstract

Preliminary results on particle spectra and fluctuations in inelastic p+p interactions measured by NA61/SHINE at the CERN SPS are presented and its future ion program is discussed. We also show results on the excitation functions of event-by-event particle ratio fluctuations in central Pb+Pb collisions from NA49 using a novel approach. We found a dependence of the results on phase space coverage which appears to explain the reported difference between measurements of NA49 and those of STAR in central Au+Au collisions.