(Anti-)deuteron production in pp collisions at $$\sqrt{s}=13 \ \text {TeV}$$ s
- PDF / 1,129,740 Bytes
- 17 Pages / 595.276 x 790.866 pts Page_size
- 57 Downloads / 186 Views
Regular Article - Experimental Physics
(Anti-)deuteron production in pp collisions at
√
s = 13 TeV
ALICE Collaboration CERN, 1211 Geneva 23, Switzerland
Received: 11 March 2020 / Accepted: 17 July 2020 © CERN for the benefit of the ALICE Collaboration 2020
Abstract The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in highenergy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged par√ ticle multiplicity in inelastic pp collisions at s = 13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (dNch /dη ∼ 26) as measured in p–Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p–Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and statistical hadronisation models (SHM).
1 Introduction High-energy collisions at the large hadron collider (LHC) create a suitable environment for the production of light (anti-)nuclei. In ultra-relativistic heavy-ion collisions light (anti-)nuclei are abundantly produced [1–3], but in elementary pp collisions their production is lower [1,4–6]. As a consequence, there are only few detailed measurements of (anti-)nuclei production rate in pp collisions. However, with the recently collected large data sample it is now possible to perform more differential measurements of light (anti-) nuclei production as a function of multiplicity and transverse momentum. In this paper, we present the detailed study of the multiplicity dependence of (anti-)deuteron production in √ pp collisions at s = 13 TeV, the highest collision energy so far delivered at the LHC. The production mechanism of light (anti-)nuclei in highenergy hadronic collisions is not completely understood. However, two groups of models have turned out to be particu e-mail:
larly useful, namely statistical hadronisation models (SHM) and coalescence models. The SHMs, which assume particle production according to the thermal equilibrium expectation, have been very successful in explaining the yields of light (anti-)nuclei along with other hadrons in Pb–Pb collisions [7], suggesting a common chemical freeze-out temperature for light (anti-)nuclei and other hadron species. The ratio between the pT -integrated yields of deuterons and protons (d/p ratio) in Pb–Pb collisions remains constant as a function of centrality, but rises in pp and p–Pb collisions with increasing multiplicity, finally reaching the value observed in Pb–Pb [1,8,9]. The constant d/p ratio in Pb–Pb collisions as a function of centrality is consistent with thermal production, suggesting that the chemical freeze-out tem
Data Loading...
