Beauty meson decays to charmonuim-like states at LHCb

TL;DR

This paper reports new observations of specific B_s meson decay modes, precise measurements of branching ratios, and the discovery of a new structure called X(4740) in the J/psi phi spectrum, advancing understanding of meson decays at LHCb.

Contribution

First observation of B_s decays to J/psi K*0 K*0 and chi_c1(3872) K+ K-, along with precise branching ratio measurements and discovery of the X(4740) structure.

Findings

Observation of B_s → J/psi K*0 K*0 decay.

Discovery of the X(4740) structure in J/psi phi spectrum.

Most precise measurement of B_s meson mass.

Abstract

The decays $B^{0}_{s} \to J\psi\pi^{+}\pi^{-}K^{+}K^{-}$ are studied using a data set corresponding to an integrated luminosity of 9fb$^{-1}$, collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The decays $B^{0}_{s} \to J\psi K^{*0}\bar{K^{*0}}$ and $B^{0}_{s} \to \chi_{c1}(3872)K^{+}K^{-}$, where the $K^{+}K^{-}$ pair does not originate from a $\phi$ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate $\chi_{c1}(3872)\phi$, $J/\psi K^{*0}\bar{K^{*0}}$, $\psi(2S) \phi$ and $\chi_{c1}(3872)K^{+}K^{-}$ states are reported. A structure denoted as $X(4740)$, is observed in the $J/\psi \phi$ mass spectrum with a significance in excess of 5.3 standard deviations. In addition, the most precise single measurement of the mass of the $B^{0}_{s}$ meson is performed.