Observation of the B_{s}^{0}→X(3872)ϕ Decay.

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The X(3872) is an exotic meson whose nature remains debated.
• Understanding its production mechanisms in different B meson decays is crucial.

Purpose of the Study:

• To report the first observation of the B_{s}^{0}→X(3872)ϕ decay.
• To investigate the production dynamics of the X(3872) in B^{0}, B_{s}^{0}, and B^{+} meson decays.

Main Methods:

• Analysis of proton-proton collision data at sqrt[s]=13 TeV, with 140 fb^{-1} integrated luminosity.
• Reconstruction of X(3872) via J/ψπ^{+}π^{-} and ϕ via K^{+}K^{-} decays.
• Measurement of branching fraction ratios involving B_{s}^{0}→X(3872)ϕ.

Main Results:

• The B_{s}^{0}→X(3872)ϕ decay is observed with a significance of 5.1σ.
• The ratio B[B_{s}^{0}→X(3872)ϕ]B[X(3872)→J/ψπ^{+}π^{-}] / B[B_{s}^{0}→ψ(2S)ϕ]B[ψ(2S)→J/ψπ^{+}π^{-}] is measured to be (2.21±0.29±0.17)%.
• Production rates suggest different dynamics for X(3872) in B^{0}/B_{s}^{0} versus B^{+} decays.

Conclusions:

• The observation of B_{s}^{0}→X(3872)ϕ provides new insights into the X(3872) particle.
• Discrepancies in production rates hint at underlying differences in B meson decay mechanisms.
• Further studies are needed to fully elucidate the nature of the X(3872).