Deuteron coalescence probability in jets in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

Abstract

This article presents the first measurement of the (anti)deuteron and antiproton transverse-momentum distributions, the deuteron coalescence parameter, and the ratio between the yields of deuteron and proton in and out of jets in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. Three regions are used to study the jet-correlated production: Toward, Away, and Transverse to the jet axis, which direction is approximated by the leading particle in the event with $p_{\rm T}^{\rm lead} > 5$ GeV/$c$. The jet contribution is obtained from the Toward region by subtracting the underlying event, which dominates the Transverse region. In p-Pb collisions, an enhancement of the coalescence parameter $B_{\rm 2}$ is observed in jets compared to the underlying event. The enhancement is larger than the one observed in a similar analysis already in pp collisions. The results are compared with predictions from PYTHIA 8.314 using the Angantyr model with a deuteron production model based on ordinary nuclear reactions. The model is able to qualitatively reproduce the large enhancement of the coalescence parameter in jets with respect to the out-of-jets one. The results are further compared in detail with similar ones from previous studies for pp collisions at $\sqrt{s} = 13$ TeV.