Flavor Changing Kaon Decays from HyperCP: Measurements of the K+/- -> pi+/- mu+ mu- Branching Ratios

TL;DR

This paper reports precise measurements of rare kaon decays involving flavor change, including the first observation of the K- -> pi- mu+ mu- decay, providing valuable data for testing theoretical models.

Contribution

It presents the first observation of the K- -> pi- mu+ mu- decay and measures its branching ratio, advancing experimental understanding of flavor-changing neutral currents.

Findings

First observation of K- -> pi- mu+ mu- decay

Measured branching ratios consistent with some theoretical models

Enhanced understanding of rare kaon decay processes

Abstract

The Fermilab HyperCP collaboration is making precision studies of charged hyperon and kaon decays, as well as searches for rare and forbidden hyperon and kaon decays. We report here on measurements of the branching ratios of the flavor-changing neutral-current decays: K+/- -> pi+/- mu+ mu-, and compare our results to theoretical predictions. This is the first observation of the K- -> pi- mu+ mu- decay.