Observation of the $B_s^0 \rightarrow J/\psi \phi \phi$ decay

TL;DR

This paper reports the first observation of the decay $B_s^0 ightarrow J/ff \, ff \, ff$ using LHCb data, measuring its branching ratio and $B_s^0$ mass with high significance.

Contribution

It presents the first observation and measurement of the $B_s^0 ightarrow J/ff \, ff \, ff$ decay channel, including mass and branching fraction ratios.

Findings

First observation of the decay with 15 sigma significance.

Measured $B_s^0$ mass as 5367.08 MeV/c$^2$ with uncertainties.

Branching fraction ratio of 0.0115 with statistical and systematic errors.

Abstract

The $B_s^0 \rightarrow J/\psi \phi \phi$ decay is observed in $pp$ collision data corresponding to an integrated luminosity of 3 fb$^{-1}$ recorded by the LHCb detector at centre-of-mass energies of 7 TeV and 8 TeV. This is the first observation of this decay channel, with a statistical significance of 15 standard deviations. The mass of the $B_s^0$ meson is measured to be $5367.08\,\pm \,0.38\,\pm\, 0.15$ MeV/c$^2$. The branching fraction ratio $\mathcal{B}(B_s^0 \rightarrow J/\psi \phi \phi)/\mathcal{B}(B_s^0 \rightarrow J/\psi \phi)$ is measured to be $0.0115\,\pm\, 0.0012\, ^{+0.0005}_{-0.0009}$. In both cases, the first uncertainty is statistical and the second is systematic. No evidence for non-resonant $B_s^0 \rightarrow J/\psi \phi K^+ K^-$ or $B_s^0 \rightarrow J/\psi K^+ K^- K^+ K^-$ decays is found.