First observation of the rare purely baryonic decay $B^0\to p\bar{p}$

Abstract

The first observation of the decay of a $B^0$ meson to a purely baryonic final state, $B^0\to p\bar{p}$, is reported. The proton-proton collision data sample used was collected with the LHCb experiment at center-of-mass energies of 7 and 8 TeV and corresponds to an integrated luminosity of 3.0 fb${}^{-1}$. The branching fraction is determined to be $$\mathcal{B}(B^0\to p\bar{p})=(1.25\pm 0.27\pm 0.18)\times 10^{-8},$$ where the first uncertainty is statistical and the second systematic. The decay mode $B^0\to p\bar{p}$ is the rarest decay of the $B^0$ meson observed to date. The decay $B_s^0\to p\bar{p}$ is also investigated. No signal is seen and the upper limit $\mathcal{B}(B_s^0\to p\bar{p})<1.5\times 10^{-8}$ at 90% confidence level is set on the branching fraction.

'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-2017-022.html