How To Kill a Penguin

TL;DR

This paper discusses how to eliminate the large flavor-changing Z-penguin contribution within minimal-flavor-violation models using precision Z decay measurements, leading to strict limits on related rare decay processes.

Contribution

It provides a detailed method to constrain the Z-penguin contribution using Z -> b anti-b observables, refining predictions for rare K- and B-decays.

Findings

Stringent bounds on non-standard contributions to the Inami-Lim function C

Tight limits on branching ratios of Z-penguin dominated decays

Enhanced understanding of flavor-changing processes in minimal-flavor-violation models

Abstract

Within constrained minimal-flavor-violation the large destructive flavor-changing Z-penguin managed to survive eradication so far. We give a incisive description of how to kill it using the precision measurements of the Z -> b anti-b pseudo observables. The derived stringent range for the non-standard contribution to the universal Inami-Lim function C leads to tight two-sided limits for the branching ratios of all Z-penguin dominated flavor-changing K- and B-decays.