Observation of the decay $Λ^0_b\rightarrowψ(2S)pπ^-$

Abstract

The Cabibbo-suppressed decay $Λ^0_b\rightarrowψ(2S)pπ^-$ 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 $ψ(2S)$ mesons are reconstructed in the $μ^+μ^-$ final state. The~branching fraction with respect to that of the $Λ^0_b\rightarrowψ(2S)pK^-$ decay mode is measured to be $$\frac{\mathcal{B}\left(Λ^0_b\rightarrowψ(2S)pπ^- \right)} {\mathcal{B}\left(Λ^0_b\rightarrowψ(2S)pK^-\right)}=\left(11.4 \pm 1.3 \pm 0.2\right)\!\%\,,$$ where the first uncertainty is statistical and the second is systematic. The $ψ(2S)p$ and $ψ(2S)π^-$ 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