Observation of the Bs0→X (3872 )ϕ Decay
Abstract
Using a data sample of proton-proton collisions at √{s }=13 TeV , corresponding to an integrated luminosity of 140 fb-1 collected by the CMS experiment in 2016-2018, the Bs0→X (3872 )ϕ decay is observed. Decays into J /ψ π+π- and K+K- are used to reconstruct, respectively, the X (3872 ) and ϕ . The ratio of the product of branching fractions B [Bs0 →X (3872 )ϕ ]B [X (3872 )→J /ψ π+π- ] to the product B [Bs0→ψ (2 S ) ϕ ]B [ψ (2 S ) →J /ψ π+π- ] is measured to be [2.21 ±0.29 (stat ) ±0.17 (syst ) ]% . The ratio B [Bs0→X (3872 )ϕ ]/B [B0 →X (3872 )K0 ] is found to be consistent with one, while the ratio B [Bs0→X (3872 )ϕ ]/B [B+ →X (3872 )K+ ] is two times smaller. This suggests a difference in the production dynamics of the X (3872 ) in B0 and Bs0 meson decays compared to B+ . The reported observation may shed new light on the nature of the X (3872 ) particle.
- Publication:
-
Physical Review Letters
- Pub Date:
- October 2020
- DOI:
- 10.1103/PhysRevLett.125.152001
- Bibcode:
- 2020PhRvL.125o2001S