Measurement of the dependence of the hadron production fraction ratio $f_\mathrm{s} / f_\mathrm{u}$ and $f_\mathrm{d} / f_ \mathrm{u}$ on B meson kinematic variables in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This study measures how the ratio of B_s to B+ hadron production fractions varies with transverse momentum and rapidity in proton-proton collisions at 13 TeV, revealing a dependence on p_T but no rapidity dependence.

Contribution

It provides the first detailed measurement of the dependence of $f_s/f_u$ on kinematic variables at 13 TeV, using CMS data, and confirms the constancy of $f_d/f_u$ across these variables.

Findings

$f_s/f_u$ depends on B meson p_T and approaches a constant at high p_T.

No significant rapidity dependence observed for $f_s/f_u$.

The ratio $f_d/f_u$ is consistent with unity and independent of kinematic variables.

Abstract

The dependence of the ratio between the B$_\mathrm{s}^0$ and B$^+$ hadron production fractions, $f_\mathrm{s} / f_\mathrm{u}$, on the transverse momentum ($p_\mathrm{T}$) and rapidity of the B mesons is studied using the decay channels B$_\mathrm{s}^0$ $\to$ J$/\psi\,\phi$ and B$^+$ $\to$ J$/\psi$ K$^+$. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6 fb$^{-1}$. The $f_\mathrm{s} / f_\mathrm{u}$ ratio is observed to depend on the B $p_\mathrm{T}$ and to be consistent with becoming asymptotically constant at large $p_\mathrm{T}$. No rapidity dependence is observed. The ratio of the B$^0$ to B$^+$ hadron production fractions, $f_\mathrm{d} / f_\mathrm{u}$, measured using the B$^0$ $\to$ J$/\psi$ K$^{*0}$ decay channel, is found to be consistent with unity and independent of $p_\mathrm{T}$ and rapidity, as expected from isospin invariance.