Search for rare B(0)((s))→μ(+)μ(-)μ(+)μ(-) decays.

Area of Science:

• Particle Physics
• High Energy Physics
• Hadron Spectroscopy

Background:

• Searches for rare B meson decays provide sensitive probes of the Standard Model and potential new physics beyond it.
• The decays B(0)((s))→μ(+)μ(-)μ(+)μ(-) are predicted to be rare within the Standard Model, making their observation a sign of new physics.
• Previous searches have placed stringent limits on these and related decays.

Purpose of the Study:

• To search for the rare decays B(0)((s))→μ(+)μ(-)μ(+)μ(-) using a large dataset collected by the LHCb detector.
• To set new upper limits on the branching fractions of these decays.
• To constrain parameters within a supersymmetric model featuring scalar and pseudoscalar particles decaying into muon pairs.

Main Methods:

• Analysis of 1.0 fb(-1) of LHCb data collected in 2011.
• Selection of candidate events with four muons in the final state.
• Statistical analysis to set upper limits on branching fractions, assuming phase-space models and specific supersymmetric scenarios.

Main Results:

• The number of observed candidates is consistent with the expected background from Standard Model processes.
• Upper limits at the 95% confidence level are set: B(B(s)(0)→μ(+)μ(-)μ(+)μ(-))<1.6×10(-8) and B(B(0)→μ(+)μ(-)μ(+)μ(-))<6.6×10(-9).
• Limits are also set for decays into hypothetical scalar (S) and pseudoscalar (P) particles within a supersymmetric context.

Conclusions:

• The absence of a significant signal places stringent constraints on the branching fractions of B(0)((s))→μ(+)μ(-)μ(+)μ(-).
• These results disfavor certain parameter space regions for new physics models, including specific supersymmetric scenarios.
• The study demonstrates the LHCb experiment's capability to probe rare B meson decays with high precision.