Amplitude Analysis of the B^{0}→K^{*0}μ^{+}μ^{-} Decay

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The Standard Model (SM) of particle physics describes fundamental particles and forces.
• Deviations from SM predictions in B meson decays can indicate new physics beyond the SM.
• Previous analyses of b- to s-quark transitions have shown tensions with SM expectations.

Purpose of the Study:

• To perform an amplitude analysis of the B^{0}→K^{*0}μ^{+}μ^{-} decay.
• To directly extract coefficients of short-distance physics effects, sensitive to new physics.
• To investigate long-distance contributions and obtain an accurate assessment of their impact.

Main Methods:

• Utilized a dataset of 4.7 fb^{-1} of pp collision data from the LHCb experiment.
• Performed a q^{2}-unbinned amplitude analysis to extract physics coefficients.
• Systematically investigated long-distance contributions from nonfactorizable QCD processes.

Main Results:

• Successfully extracted coefficients of short-distance physics effects for the first time directly from data.
• Obtained the most accurate assessment to date of long-distance contributions' impact.
• Observed deviations from SM predictions at the 1.8 standard deviation level, with a global significance of 1.4 standard deviations.

Conclusions:

• The measured corrections to short-distance couplings are consistent with previous b- to s-quark transition analyses.
• The observed discrepancies with SM predictions are modest but warrant further investigation.
• This analysis provides crucial data for probing physics beyond the Standard Model.