Production of nuclei and antinuclei in pp and Pb-Pb collisions with ALICE at the LHC

TL;DR

This paper reports the first measurements of nuclei and antinuclei production in proton-proton and lead-lead collisions at the LHC, using ALICE detector data to analyze their yields and compare with thermal model predictions.

Contribution

It provides the first experimental results on light nuclei and antinuclei production in high-energy collisions at the LHC, with detailed particle identification and statistical analysis.

Findings

Observation of significant numbers of light nuclei and antinuclei in Pb-Pb collisions.

Comparison of particle ratios with thermal model predictions.

High-statistics data enabling detailed study of nuclei production mechanisms.

Abstract

We present first results on the production of nuclei and antinuclei such as (anti)deuterons, (anti)tritons, (anti)3He and (anti)4He in pp collisions at $\s$ = 7 TeV and Pb-Pb collisions at $\sNN$ = 2.76 TeV. These particles are identified using their energy loss (dE/dx) information in the Time Projection Chamber of the ALICE experiment. The Inner Tracking System gives a precise determination of the event vertex, by which primary and secondary particles are separated. The high statistics of over 360 million events for pp and 16 million events for Pb-Pb collisions give a significant number of light nuclei and antinuclei (Pb-Pb collisions: \sim30,000 anti-deuterons($\bar{d}$) and \sim4 anti-alpha($\bar{^4He}$)). The predictions of various particle ratios from the THERMUS model is also discussed.