Event-by-event anti-deuteron multiplicity fluctuation in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV

TL;DR

This study models anti-deuteron production and its fluctuations in Pb+Pb collisions at 5.02 TeV, revealing suppression in peripheral collisions and Poissonian multiplicity fluctuations consistent with experimental data.

Contribution

It introduces a hybrid model combining MUSIC hydrodynamics and UrQMD transport to analyze anti-deuteron fluctuations, highlighting deviations from simple coalescence predictions.

Findings

Anti-deuteron to antiproton ratio suppressed in peripheral collisions

Anti-deuteron multiplicity follows Poisson distribution across centralities

Negative correlation between anti-deuteron and antiproton multiplicities

Abstract

Using the nucleon coalescence model based on kinetic freeze-out nucleons from the hybrid model of MUSIC hydrodynamics and UrQMD hadronic transport, we study the production of anti-deuteron and its event-by-event fluctuation in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV. We find a clear suppression of the anti-deuteron to antiproton yield ratio in peripheral collisions, which is in accordance with the measurements from the ALICE Collaboration. Also found is a Poissonian event-by-event fluctuation of the anti-deuteron multiplicity distribution in all collision centralities, which is different from the prediction of a simple coalescence model calculation that assumes all antiproton and antineutron pairs to have the same probability to form anti-deuterons. We further find a small negative correlation between the anti-deuteron and antiproton multiplicity distributions as a result of the baryon conservation.