Search for the doubly heavy baryons Ω _bc ⁰and Ξ _bc ⁰decaying to Λ _c ⁺π- And Ξ _c ⁺π- And c

The first search for the doubly heavy Ωbc0 baryon and a search for the Ξbc0 baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.2 fb - 1. The baryons are reconstructed via their decays to Λc+ π- and Ξc+ π-. No significant excess is found for invariant masses between 6700 and 7300, in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c2. Upper limits are set on the ratio of the Ωbc0 and Ξbc0 production cross-section times the branching fraction to Λc+ π- (Ξc+ π-) relative to that of the Λb0 (Ξb0) baryon, for different lifetime hypotheses, at 95% confidence level. The upper limits range from 0.5 × 10-4 to 2.5 × 10-4 for the Ωbc0 → Λc+ π- (Ξbc0 → Λc+ π-) decay, and from 1.4 × 10-3 to 6.9 × 10-3 for the Ωbc0 → Ξc+ π- (Ξbc0 → Λc+ π-) decay, depending on the considered mass and lifetime of the Ωbc0 (Ξbc0) baryon.