Evidence for Modification of $b$ Quark Hadronization in High-Multiplicity $pp$ Collisions at $\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}$

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Evidence for Modification of $b$ Quark Hadronization in High-Multiplicity $p p$ Collisions at $\sqrt{s} = 13 TeV$

R. Aaij et al. (LHCb Collaboration)

Phys. Rev. Lett. 131, 061901 – Published 10 August 2023

Abstract

The production rate of $B_{s}^{0}$ mesons relative to $B^{0}$ mesons is measured by the LHCb experiment in $p p$ collisions at a center-of-mass energy $\sqrt{s} = 13 TeV$ over the forward rapidity interval $2 < y < 4.5$ as a function of the charged particle multiplicity measured in the event. Evidence at the $3.4 σ$ level is found for an increase of the ratio of $B_{s}^{0}$ to $B^{0}$ cross sections with multiplicity at transverse momenta below $6 GeV / c$ , with no significant multiplicity dependence at higher transverse momentum. Comparison with data from $e^{+} e^{-}$ collisions implies that the density of the hadronic medium may affect the production rates of $B$ mesons. This is qualitatively consistent with the emergence of quark coalescence as an additional hadronization mechanism in high-multiplicity collisions.

Received 28 April 2022
Revised 24 September 2022
Accepted 20 January 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.061901

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