$B$-jet fragmentation with $B^{\pm} \to J/\psi K^{\pm}$ decays in $\sqrt{s} = 13$ TeV $pp$ collisions at LHCb

TL;DR

This paper measures the fragmentation functions and radial profiles of $B^{ mootnotesize extpm}$ mesons within jets at 13 TeV, revealing insights into heavy-flavor hadron production and gluon fragmentation contributions.

Contribution

It provides the first detailed measurements of $B^{ mootnotesize extpm}$ jet fragmentation functions and profiles at LHC energies, highlighting the increasing role of gluon fragmentation.

Findings

Gluon fragmentation contribution increases with jet transverse momentum.

Measured fragmentation functions are consistent with some theoretical models.

Results enhance understanding of heavy-flavor production in high-energy collisions.

Abstract

The collinear and transverse-momentum-dependent jet fragmentation function and the radial profile for $B^{\pm}$ mesons in jets are measured. The $B^{\pm}$ mesons are reconstructed through the $J/\psi (\to \mu^{+} \mu^{-}) K^{\pm}$ decay channel using proton-proton collision data collected during 2016-2018 with the LHCb detector at a center-of-mass energy of $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of $5.4$ fb$^{-1}$. The results complement recent measurements of jet fragmentation functions for heavy-flavor hadrons and suggest a growing contribution of gluon fragmentation to $B^{\pm}$ mesons as the jet transverse momentum increases.