Rare B0_(s) -> mu+mu- decays

TL;DR

This review summarizes the current experimental efforts and results on measuring the rare B0_s -> mu+mu- decays, which are crucial for testing the Standard Model and probing new physics.

Contribution

It compiles and analyzes the latest experimental upper limits and the nearing observation of B0_s -> mu+mu- decays from major collider experiments.

Findings

Branching fraction upper limits are close to Standard Model predictions.

First observation of B0_s -> mu+mu- decay is imminent.

Measurements constrain extensions of the Standard Model.

Abstract

This review summarizes the current experimental results on rare B0_(s) -> mu+mu- decays of the Tevatron experiments CDF and D0, and the LHC experiments ATLAS, CMS and LHCb. The experimental branching fraction upper limits for the B0_s -> mu+mu- are already quite close to the branching fraction predicted by the Standard Model, and the first observation of the B0_s -> mu+mu- decay is expected soon. The rare decays B0_(s) -> mu+mu- are highly suppressed in the Standard Model, and therefore accurate measurements of these branching fractions provide complementary constraints to the free parameters of various extensions of the Standard Model.