A novel observable for $C\!P$ violation in multi-body decays and its application potential to charm and beauty meson decays

TL;DR

The paper introduces a new observable, FBI-CP asymmetry, for detecting $C ext{-}P$ violation in multi-body heavy meson decays, which isolates interference effects and enhances statistical sensitivity.

Contribution

It proposes the FBI-CP asymmetry as a novel measurement tool that improves $C ext{-}P$ violation detection in heavy meson decays by isolating interference effects and increasing statistical power.

Findings

FBI-CP asymmetry isolates interference-induced $C ext{-}P$ violation.

It nearly doubles the statistical sensitivity compared to traditional methods.

Applicable to charm and beauty meson decay channels.

Abstract

A novel observable measuring the $C\!P$ asymmetry in multi-body decays of heavy mesons, which is called the forward-backward asymmetry induced $C\!P$ asymmetry (FBI-$C\!P$A), $A_{CP}^{FB}$, is introduced. This observable has the dual advantages that 1) it can isolate the $C\!P$ asymmetry associated with the interference of the $S$- and $P$-wave amplitude from that associated with the $S$- or $P$-wave amplitude alone; 2) it can effectively almost double the statistics comparing to the conventionally defined regional $C\!P$ asymmetry. We also suggest to perform the measurements of FBI-$C\!P$A in some three-body decay channels of charm and beauty mesons.