Study of $B_s^0\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}{K}^{+}{K}^{-}$ decays

Abstract

The decays $B_s^0\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}{K}^{+}{K}^{-}$ 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 13TeV. The decays $B_s^0\to J/\ddot{I}ˆK^{\ast 0}{\bar{K}}^{\ast 0}$ and $B_s^0\to \ddot{I}{‡}_{c1}(3872)K^{+}{K}^{-}$, where the $K^{+}{K}^{-}$ pair does not originate from a $\ddot{I}•$ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate $\ddot{I}{‡}_{c1}(3872)\ddot{I}•$, $J/\ddot{I}ˆK^{\ast 0}{\bar{K}}^{\ast 0}$, $\ddot{I}ˆ(2S)\ddot{I}•$ and $\ddot{I}{‡}_{c1}(3872)K^{+}{K}^{-}$ states are reported. A structure, denoted as $X(4740)$, is observed in the $J/\ddot{I}ˆ\ddot{I}•$ mass spectrum and, assuming a Breit-Wigner parameterisation, its mass and width are determined to be \begin{eqnarray*} m_{X(4740)} & = & 4741 \pm 6 \pm 6\,{\mathrm{MeV}}/c^2 \,, \\ Γ_{X(4740)} & = & 53 \pm 15 \pm 11\,{\mathrm{MeV}} \,, \end{eqnarray*} where the first uncertainty is statistical and the second is systematic. In addition, the most precise single measurement of the mass of the $B_s^0$ meson is performed and gives a value of $$m_{B_s^0}=5366.98\pm 0.07\pm 0.13\mathrm{MeV}/c^2.$$

32 pages, 10 figures; All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-035.html (LHCb public pages)"