Light (hyper-)nuclei production at the LHC measured with ALICE

Francesco Barile,L Bravina,Y Foka,S Kabana

doi:10.1051/epjconf/20149504003

Francesco Barile, L Bravina + Show 2 more

Open Access

https://doi.org/10.1051/epjconf/20149504003

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Abstract

The high center-of-mass energies delivered by the LHC during the last three years of operation led to accumulate a significant statistics of light (hyper-)nuclei in pp, p--Pb and Pb--Pb collisions. The ALICE apparatus allows for the detection of these rarely produced particles over a wide momentum range thanks to its excellent vertexing, tracking and particle identification capabilities. The last is based on the specific energy loss in the Time Projection Chamber and the velocity measurement with the Time-Of-Flight detector. The Cherenkov technique, exploited by a small acceptance detector (HMPID), has also been used for the most central Pb--Pb collisions to identify (anti-)deuterons at intermediate transverse momentum. Results on the production of stable nuclei and anti-nuclei in pp, p--Pb and Pb--Pb collisions are presented. Hypernuclei production rates in Pb--Pb are also described, together with a measurement of the hypertriton lifetime. The results are compared with the predictions from thermal and coalescence models. Moreover the results on the search for weakly-decaying light exotic states, such as the $\Lambda\Lambda$ (H-dibaryon) and the $\Lambda$-neutron bound states are discussed.

Highlights

Collisions of ultra-relativistic heavy ions provide a unique experimental condition to produce nuclei and hypernuclei thanks to the huge amount of energy deposited into a volume much larger than i√n pp sNN collisions
The production mechanisms of these particles are typically discussed within two approaches: the statistical thermal model and the coalescence model
The particle identification (PID) detectors relevant for the analysis presented in this contribution are briefly described

Summary

Introduction

Collisions of ultra-relativistic heavy ions provide a unique experimental condition to produce nuclei and hypernuclei thanks to the huge amount of energy deposited into a volume much larger than i√n pp sNN collisions. The measurements presented here, have = 2.76 TeV as a function of collision centrality and ibnepe–nPpbercfoolrlmisieodnsinatPb√–sPNbN collisions at = 5.02 TeV as a function of charged-particle multiplicity. The unique particle identification capabilities of the ALICE detector [1] system is suited to measure nuclei and hypernuclei and for the search of exotic states like Λn bound states and the. The production mechanisms of these particles are typically discussed within two approaches: the statistical thermal model and the coalescence model. In the thermal model [2,3,4].

Particle identification in ALICE

Nuclei

Background

Hypertriton

Exotica bound states