B(s,d)→ℓ(+)ℓ(-) in the standard model with reduced theoretical uncertainty

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Field Theory

Background:

• The Standard Model (SM) describes fundamental particles and forces.
• Precision measurements of rare B meson decays provide stringent tests of the SM.
• Theoretical uncertainties in branching ratio predictions have historically limited these tests.

Purpose of the Study:

• To provide updated, precise branching ratio predictions for Bs,d→ℓ+ℓ- decays within the Standard Model.
• To incorporate new theoretical corrections to reduce uncertainties in these predictions.
• To compare theoretical predictions with experimental observations, particularly for the muonic decay of the Bs meson.

Main Methods:

• Combining new O(αem) and O(αs2) perturbative corrections to the decay amplitudes.
• Calculating updated branching ratio predictions for Bs→μ+μ- and Bd→μ+μ- decays.
• Analyzing the impact of new corrections on theoretical uncertainties.

Main Results:

• Updated branching ratio prediction for Bs→μ+μ- is (3.65±0.23)×10-9.
• Inclusion of new corrections significantly reduces theoretical uncertainties of perturbative origin.
• The new corrections begin to dominate over parametric uncertainties.

Conclusions:

• The updated predictions offer improved precision for testing the Standard Model.
• The calculated value for Bs→μ+μ- is in good agreement with recent experimental observations.
• Further theoretical and experimental advancements are crucial for precision tests of particle physics.