Strong constraints on the rare decays B(s)(0) → μ+ μ- and B0 → μ+ μ-

Area of Science:

• Particle Physics
• High-Energy Physics
• Standard Model

Background:

• Rare B meson decays provide sensitive probes of new physics beyond the Standard Model.
• The decays B(s)(0) → μ+ μ- and B0 → μ+ μ- are particularly sensitive to contributions from new particles and interactions.
• Previous searches have placed stringent limits on these branching fractions.

Purpose of the Study:

• To search for the rare decays B(s)(0) → μ+ μ- and B0 → μ+ μ-.
• To set new upper limits on the branching fractions of these decays.
• To test the predictions of the Standard Model in the flavor physics sector.

Main Methods:

• Analysis of 1.0 fb⁻¹ of pp collision data collected at √s = 7 TeV.
• Utilized the LHCb detector at the Large Hadron Collider.
• Statistical analysis to distinguish signal from background and set limits.

Main Results:

• Observed event yields are consistent with Standard Model background and signal expectations.
• Established upper limits on branching fractions: B(B(s)(0) → μ+ μ-) < 4.5(3.8)×10⁻⁹ and B(B0 → μ+ μ-) < 1.0(0.81)×10⁻⁹ at 95%(90%) confidence level.
• These results constrain new physics scenarios.

Conclusions:

• The Standard Model predictions for these rare decays are consistent with the experimental observations.
• The stringent upper limits further restrict parameter space for theories beyond the Standard Model.
• The LHCb experiment continues to provide crucial data for precision tests of the Standard Model.