Observation of the Annihilation Decay Mode B^{0}→K^{+}K^{-}

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The Standard Model of particle physics predicts various decay modes for B mesons.
• Understanding these decays provides insights into fundamental interactions and the properties of quarks.
• Previous searches for the B0→K+K- decay had not yielded a definitive observation.

Purpose of the Study:

• To search for and observe the B0→K+K- decay for the first time.
• To perform an improved measurement of the branching fraction for the Bs0→π+π- decay.
• To contribute to the precise determination of fundamental parameters in particle physics.

Main Methods:

• Analysis of proton-proton collision data collected by the LHCb experiment.
• Utilizing integrated luminosities of 1.0 fb⁻¹ at 7 TeV and 2.0 fb⁻¹ at 8 TeV.
• Statistical analysis to establish the significance of the observed decay and measure branching fractions.

Main Results:

• The B0→K+K- decay was observed for the first time with a significance exceeding 5 standard deviations.
• The branching fraction for B0→K+K- was measured to be (7.80±1.27±0.81±0.21)×10⁻⁸.
• An improved measurement of the branching fraction for Bs0→π+π- was obtained as (6.91±0.54±0.63±0.19±0.40)×10⁻⁷.

Conclusions:

• The observation of B0→K+K- marks a significant advancement in the study of B meson decays.
• The precise measurements of branching fractions provide crucial data for testing theoretical models.
• This research enhances our understanding of flavor physics at the LHC.