Consistent description of angular correlations in $\beta$ decay for Beyond Standard Model physics searches

Understand

Measurements of angular correlations between initial and final particles in $\beta$ decay remain one of the most promising ways of probing the Standard Model and looking for new physics.

• As experiments reach unprecedented precision well into the per-mille regime, proper extraction of results requires one to take into account a great number of nuclear structure and radiative corrections in a procedure which becomes dependent upon the experimental geometry.
• We provide here a compilation and update of theoretical results which describe all corrections in the same conceptual framework, point out pitfalls and review the influence of the experimental geometry.
• Finally, we summarize the potential for new physics reach.