Observation of the decay B(c)(+) → B(s)(0)π+

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The study of B meson decays provides crucial insights into the Standard Model of particle physics.
• Understanding rare decay modes helps to probe fundamental interactions and search for new physics beyond the Standard Model.

Purpose of the Study:

• To search for and observe the decay of the B(c)+ meson into a B(s)0 meson and a pion (B(c)+ → B(s)0 π+).
• To measure the product of the ratio of cross sections and branching fraction for this decay channel.

Main Methods:

• Analysis of proton-proton collision data collected by the LHCb detector at center-of-mass energies of 7 TeV and 8 TeV.
• Utilized B(s)0 → D(s)-π+ and B(s)0 → J/ψ φ decay channels for the analysis.
• Statistical significance determined to be in excess of 5 standard deviations.

Main Results:

• The decay B(c)+ → B(s)0 π+ was observed with high statistical significance ( > 5σ) in both decay channels.
• The measured product of cross-section ratio and branching fraction is [σ(B(c)+)/σ(B(s)0)] × B(B(c)+→ B(s)0π+) = (2.37 ± 0.31(stat) ± 0.11(syst) ± 0.17(τ(B(c)+))) × 10⁻³.
• This is the first observation of a B meson decaying into another B meson via the weak interaction.

Conclusions:

• The observation of B(c)+ → B(s)0 π+ provides a new channel to study B meson physics.
• This finding contributes to the comprehensive understanding of weak decays in the heavy quark sector.