Observation of the decay $B_s^0\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and evidence for $B^0\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$

Abstract

The first observation of the rare decay$B_s^0\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and evidence for $B^0\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ are reported, using $pp$ collision data recorded by the LHCb detector at centre-of-mass energies $\sqrt{s}=7$ and 8~TeV, corresponding to an integrated luminosity of $3{\mbox{\,fb}^{-1}}$. The branching fractions in the $\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ invariant mass range $400<m(\ddot{I}{€}^{+}\ddot{I}{€}^{-})<1600\mathrm{Me}\mathrm{V}/c^2$ are $[3.48\pm 0.23\pm 0.17\pm 0.35]\times 10^{-6}$ and $[1.82\pm 0.25\pm 0.41\pm 0.14]\times 10^{-7}$ for $B_s^0\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and $B^0\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ respectively, where the uncertainties are statistical, systematic and from the normalisation mode $B_s^0\to \ddot{I}•\ddot{I}•$. A combined analysis of the $\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ mass spectrum and the decay angles of the final-state particles identifies the exclusive decays $B_s^0\to \ddot{I}•f_0(980)$, $B_s^0\to \ddot{I}•f_2(1270)$, and $B_s^0\to \ddot{I}•\ddot{I}{}^0$ with branching fractions of $[1.12\pm 0.16_{-0.08}^{+0.09}\pm 0.11]\times 10^{-6}$, $[0.61\pm 0.13_{-0.05}^{+0.12}\pm 0.06]\times 10^{-6}$ and $[2.7\pm 0.7\pm 0.2\pm 0.2]\times 10^{-7}$, respectively.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-028.html