Search for hidden-sector bosons in $B^0\to K^{\ast 0}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ decays

Abstract

A search is presented for hidden-sector bosons, $\ddot{I}‡$, produced in the decay $B^0\to K^{\ast }(892{)}^0\ddot{I}‡$, with $K^{\ast }(892{)}^0\to K^{+}\ddot{I}{€}^{-}$ and $\ddot{I}‡\to \hat{I}{¼}^{+}\hat{I}{¼}^{-}$. The search is performed using $pp$-collision data corresponding to 3.0 fb${}^{-1}$ collected with the LHCb detector. No significant signal is observed in the accessible mass range $214\le m(\ddot{I}‡)\le 4350$ MeV, and upper limits are placed on the branching fraction product $\mathcal{B}(B^0\to K^{\ast }(892{)}^0\ddot{I}‡)\times \mathcal{B}(\ddot{I}‡\to \hat{I}{¼}^{+}\hat{I}{¼}^{-})$ as a function of the mass and lifetime of the $\ddot{I}‡$ boson. These limits are of the order of $10^{-9}$ for $\ddot{I}‡$ lifetimes less than 100 ps over most of the $m(\ddot{I}‡)$ range, and place the most stringent constraints to date on many theories that predict the existence of additional low-mass bosons.

All figures and tables, along with supplementary material, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-036.html