Rare $B$ Decays as Tests of the Standard Model

TL;DR

Rare $B$ decays are crucial for testing the Standard Model and constraining new physics, with ongoing research providing insights into fundamental particle interactions and guiding future theoretical developments.

Contribution

This review summarizes the current status and future prospects of rare $B$ decays as tools for probing the Standard Model and searching for new physics.

Findings

Strong constraints on new physics energy scales from rare decays

Rare $b$ decays help understand Standard Model patterns

Potential to guide new physics model building

Abstract

One of the most interesting puzzles in particle physics today is that new physics is expected at the TeV energy scale to solve the hierarchy problem, and stabilise the Higgs mass, but so far no unambiguous signal of new physics has been found. Strong constraints on the energy scale of new physics can be derived from precision tests of the electroweak theory and from flavour-changing or CP-violating processes in strange, charm and beauty hadron decays. Decays that proceed via flavour-changing-neutral-current processes are forbidden at the lowest perturbative order in the Standard Model and are, therefore, rare. Rare $b$ hadron decays are playing a central role in the understanding of the underlying patterns of Standard Model physics and in setting up new directions in model building for new physics contributions. In this article the status and prospects of this field are reviewed.