Observation of the decay $\hat{I}{›}_b^0\to \ddot{I}ˆ(2S)p\ddot{I}{€}^{-}$

Abstract

The Cabibbo-suppressed decay $\hat{I}{›}_b^0\to \ddot{I}ˆ(2S)p\ddot{I}{€}^{-}$ is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9fb${}^{-1}$ of integrated luminosity at centre-of-mass energies of 7, 8 and 13TeV, respectively. The $\ddot{I}ˆ(2S)$ mesons are reconstructed in the $\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ final state. The~branching fraction with respect to that of the $\hat{I}{›}_b^0\to \ddot{I}ˆ(2S)p{K}^{-}$ decay mode is measured to be $$\frac{\mathcal{B}\left(\hat{I}{›}_b^0\to \ddot{I}ˆ(2S)p\ddot{I}{€}^{-}\right)}{\mathcal{B}\left(\hat{I}{›}_b^0\to \ddot{I}ˆ(2S)p{K}^{-}\right)}=\left(11.4\pm 1.3\pm 0.2\right)\%,$$ where the first uncertainty is statistical and the second is systematic. The $\ddot{I}ˆ(2S)p$ and $\ddot{I}ˆ(2S)\ddot{I}{€}^{-}$ mass spectra are investigated and no evidence for exotic resonances is found.

16 pages, 2 figures. 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-2018-022.html