First measurement of the relative production of $B_s^0$ and $B^+$ mesons $f_s/f_u$ in $pp$ collisions at $\sqrt s = 13.6 ~ \mathrm{TeV}$

by Daniele Provenzano (Università degli Studi di Cagliari, INFN Cagliari)

Friday 11 Sept 2026, 15:00 → 16:00 Europe/Berlin

CP-03-123 - E5a Seminarraum (TUDortmund)

A new measurement of the ratio of the $B_s^0$ and $B^+$ fragmentation fractions, $f_s$/$f_u$, will be presented. The measurement is performed with $B_s^0 \to J/\psi \phi$ and $B^+ \to J/\psi K^+$ decays in $pp$ collisions for the first time at a centre-of-mass energy of $\sqrt s = 13.6~\mathrm{TeV}$, using LHCb Run 3 data collected with the all-new LHCb Upgrade detector in 2024. The dependence of this observable on $B$-meson kinematic variables is also discussed, confirming the dependence on transverse momentum. Finally, the combination of this measurement with previous LHCb results at different centre-of-mass energies will be shown.