Measurement of the Branching Fractions B(B0 → p anti-p p anti-p) and B(B0s → p anti-p p anti-p)

Searches for the rare hadronic decays B0 → p anti-p p anti-p and B0s → p anti-p p anti-p are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of 9 fb^− 1. Significances of 9.3 σ and 4.0 σ, including statistical and systematic uncertainties, are obtained for the B0 → p anti-p p anti-p and B0s → p anti-p p anti-p signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays B0 → J/ψ(→ p anti-p) K*0(→ K+ π−) and B0s → J/ψ(→ p anti-p) × ϕ(→ K+ K−). The branching fractions are measured to be B(B0 → p anti-p p anti-p) = (2.2 ± 0.4 ± 0.1 ± 0.1) × 10^−8 and B(B0s → p anti-p p anti-p) = (2.3 ± 1.0 ± 0.2 ± 0.1) × 10^−8. In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.