Observation of the $B^{0}_(s)\rightarrow J/\psi p\overline{p}$ decays and precise $B^{0}_{s}$ mass measurement.

Fu J., Neri N., Spadaro Norella E.

Comunicazione
I - Fisica nucleare e subnucleare
Aula 32B-1 - Martedì 18 h 10:45 - 13:00
The first observation of the baryonic $B^{0}_(s)\rightarrow J/\psi p \overline{p}$ decays is reported using a data sample corresponding to an integrated luminosity of 5.3 fb${}^{-1}$, collected by the LHCb experiment in $pp$ collisions at the centre-of-mass energies of 7, 8, and 13 TeV. The corresponding branching fractions are measured with respect to the normalisation mode $B^{0}_{s}\rightarrow J/\psi K^{+}K^{-}$. The small $Q$-values of the $B^{0}_{s}\rightarrow J/\psi p \overline{p}$ reaction allows for a precise measurement of the $B_{s}^{0}$ mass that is also performed. The study for these decays has interesting physics motivations due to the sensitivity to new exotic states such as glueball and pentaquarks, which can occur in the $p \overline{p}$ and $J/\psi p(\overline{p})$ invariant masses, respectively. This possibility is supported by the measured enhancement of the $B_{s}^{0}$ branching fraction with respect to theoretical predictions.