Volume 314 - The European Physical Society Conference on High Energy Physics (EPS-HEP2017) - Heavy Ion Physics (Parallel Session). Conveners: Ralf Averbeck; Raphael Granier de Cassagnac; Carlos Salgado. Scientific Secretary: Andrea Dainese.
Recent results on (anti-)(hyper-)nuclei production in pp, p-Pb and Pb-Pb collisions with ALICE
S. Trogolo* On behalf of the ALICE collaboration
*corresponding author
Full text: pdf
Pre-published on: 2017 November 29
Published on: 2018 March 20
Abstract
The ALICE Collaboration has collected a large data sample of Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV in 2015 at the Large Hadron Collider (LHC), which is complementary to that at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV from Run 1. In these collisions, a great variety of (anti-)(hyper-)nuclei is produced, namely deuteron, triton, $^3$He, $^4$He, hypertriton ($^3_{\Lambda}$H) and their antiparticles. Furthermore, the high quality data sample of pp collisions at $\sqrt{s}$ = 7 TeV and 13 TeV and p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV, collected at the LHC, allows for a systematic study of the light (anti-)nuclei production in different collision systems.

ALICE has excellent particle identification (PID) capabilities which allow for the detection of these rarely produced particles. PID is performed using several techniques, namely by exploiting the measurement of the specific energy-loss in the Time Projection Chamber (TPC) and the information of the Time-Of-Flight (TOF) detector. In addition, the Inner Tracking System (ITS) is used to distinguish secondary vertices originating from weak decays. This is extremely important for the measurement of (anti-)hypertriton which has a decay length of several centimeters. The decay mode into 2-body ($^3_{\Lambda}$H $\rightarrow ^3$He + $\pi^-$) is the one with the highest reconstruction efficiency, but the largest branching ratio is given by the 3-body decay channel ($^3_{\Lambda}$H $\rightarrow$ d + p + $\pi^-$).
Emphasis will be put on new results on nuclei production as a function of transverse momentum and multiplicity in all the collision systems as well as on the latest and more precise measurement of the hypertriton lifetime.
The results on (hyper-)nuclei production are compared with predictions from a model based on coalescence mechanism and from statistical-thermal models. The goal is to study the (hyper-)nuclei production mechanisms in heavy-ion collisions (Pb-Pb) and to compare them to those in small collision (pp, p-Pb) systems.
DOI: https://doi.org/10.22323/1.314.0200
Open Access