The s ---> d gamma decay in and beyond the Standard Model

TL;DR

This paper investigates the sensitivity of the s ---> d gamma decay process to New Physics beyond the Standard Model, improving predictions and exploring various new physics scenarios through FCNC transitions.

Contribution

It provides improved Standard Model predictions for CP violation in radiative K decays and introduces a new strategy to distinguish electroweak and QCD penguin contributions.

Findings

Subleading magnetic contribution to epsilon prime even with New Physics.

Enhanced understanding of FCNC transitions in s ---> d sector.

A new method to differentiate electroweak and QCD penguin effects.

Abstract

The New Physics sensitivity of the s ---> d gamma transition and its accessibility through hadronic processes are thoroughly investigated. Firstly, the Standard Model predictions for the direct CP-violating observables in radiative K decays are systematically improved. Besides, the magnetic contribution to epsilon prime is estimated and found subleading, even in the presence of New Physics, and a new strategy to resolve its electroweak versus QCD penguin fraction is identified. Secondly, the signatures of a series of New Physics scenarios, characterized as model-independently as possible in terms of their underlying dynamics, are investigated by combining the information from all the FCNC transitions in the s ---> d sector.