Femtoscopic study of the proton-proton and proton-deuteron systems in heavy-ion collisions at the LHC

Abstract

This work reports femtoscopic correlations of p$-$p ($\bar{\mathrm{p}}-\bar{\mathrm{p}}$) and p$-$d ($\bar{\mathrm{p}}-\bar{\mathrm{d}}$) pairs measured in Pb$-$Pb collisions at center-of-mass energy per nucleon $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV in the ALICE Collaboration. A fit to the measured proton-proton correlation functions allows one to extract the dependence of the nucleon femtoscopic radius of the particle-emitting source on the pair transverse mass ($m_{\text{T}}$) and on the average charge particle multiplicity $⟨{\text{dN}}_{\text{ch}}/\text{d}\hat{I}\cdot {⟩}^{1/3}$ for three centrality intervals (0$-$10$\%$, 10$-$30$\%$, 30$-$50$\%$). In both cases, the expected power-law and linear scalings are observed, respectively. The measured p$-$d correlations can be described by both two- and three-body calculations, indicating that the femtoscopy observable is not sensitive to the short-distance features of the dynamics of the p$-$(p$-$n) system, due to the large inter-particle distances in Pb$-$Pb collisions at the LHC. Indeed, in this study, the minimum measured femtoscopic source sizes for protons and deuterons have a minimum value at $2.73_{-0.05}^{+0.05}$ and $3.10_{-0.86}^{+1.04}$ fm, respectively, for the 30$-$50$\%$ centrality collisions. Moreover, the $m_{\mathrm{T}}$-scaling obtained for the p$-$p and p$-$d systems is compatible within 1$\ddot{I}ƒ$ of the uncertainties. These findings provide new input for fundamental studies on the production of light (anti)nuclei under extreme conditions.

26 pages, 3 captioned figures, 4 tables, authors from page 20, figures at http://alice-publications.web.cern.ch/node/12394

Cited by in corpus (1)

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