Production of light nuclei and anti-nuclei in pp and Pb-Pb collisions at LHC energies

Submission Date: 
30/06/2015
Article Information
Submission Form
System: 
p-p
System: 
Pb-Pb
Energy: 
2.76 TeV
Energy: 
7 TeV
Abstract Plain Text: 

The production of (anti-)deuteron, (anti-)triton and (anti-)3He nuclei in pp collisions at $\sqrt{s} = 7$ TeV
and in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV has been measured using the ALICE detector at
the LHC. The Pb-Pb spectra exhibit a significant hardening with increasing centrality due to radial
flow demonstrating that they show signatures of the evolution to the kinetic freeze-out. This behavior is
demonstrated by combined blast-wave fits of several particles. The integrated particle yields are discussed
with respect to coalescence and thermal-statistical model expectations. The particle ratios, d/p and 3He/p,
in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of
$T_{\rm chem} \approx 156$ MeV while the d/p ratio in pp collisions is lower by a factor of 2.5 than in Pb-Pb collisions.
Furthermore, no significant centrality dependence in these ratios is observed, favoring coalescence models in which nuclei
production is proportional to particle density instead of absolute particle multiplicity. Using source parameters from two-pion HBT
analyzes in the coalescence approach, one can successfully approximate the deuteron and 3He data illustrating that
both processes are governed by the same lengths of homogeneity.

Depends on https://aliceinfo.cern.ch/ArtSubmission/node/121