Cascade Mixing and the CP-Violating Angle Beta

TL;DR

This paper discusses how cascade mixing in B meson decays can measure cos(2*beta), helping to resolve discrete ambiguities in CP-violating phase angles in the Standard Model.

Contribution

It proposes using cascade mixing in B decays to directly measure cos(2*beta), reducing ambiguities in CP violation parameter determination.

Findings

Cascade mixing enables measurement of cos(2*beta)

This method can resolve discrete ambiguities in CP phase angles

It enhances understanding of CP violation in B meson decays

Abstract

In the decay chain B(d) --> Psi + K --> Psi + (pi l nu), neutral K mixing follows on the heels of neutral B mixing. This "cascade mixing" leads to an interference which probes cos(2*beta), where beta is one of the three CP-violating phase angles which characterize CP violation in the Standard Model. Widely-discussed future B-system experiments will determine trigonometric functions of these three phase angles, leaving the underlying angles themselves discretely ambiguous. A determination of cos(2*beta) through cascade mixing would eliminate all the discrete ambiguities entirely.