Event-by-Event Fluctuations and the Search for the Critical Point within the NA49 Experiment

TL;DR

This paper reports on event-by-event fluctuation analyses in heavy-ion collisions at CERN SPS to search for the QCD critical point, providing new insights into phase transition signals and hadronic observable fluctuations.

Contribution

It presents novel fluctuation measurements, especially of K/p ratios, linking experimental results to theoretical predictions about the QCD phase transition and critical point.

Findings

Observation of significant K/p fluctuation patterns

Potential connection between strangeness and baryon number fluctuations

Results support the existence of a critical point in strongly interacting matter

Abstract

In heavy-ion collisions in the energy regime probed at the CERN SPS, experimental hints for the deconfinement phase transition have been seen in numerous inclusive hadronic observables. In order to further characterize this transition, and in the pursuit of indications for the expected critical point of strongly interacting matter, the NA49 collaboration has conducted analyses of the event-by-event fluctuations of various hadronic observables. A selection of these results will be presented and discussed in the light of theoretical predictions. Among these are new results on hadron ratio fluctuations, in particular K/p fluctuations and their potential connection to the correlation between strangeness and baryon number, thus revealing the basic degrees of freedom produced in heavy-ion collisions.