Using time-dependent indirect $CP$ asymmetries to measure $T$ and $CPT$ violation in $B^0$-${\bar B}^0$ mixing

TL;DR

This paper demonstrates that time-dependent indirect $CP$ asymmetries in $B$ decays can be used to measure $T$ and $CPT$ violation in $B^0$-${ar B}^0$ mixing without requiring entangled states or neglecting penguin pollution.

Contribution

It introduces a method to measure $T$ and $CPT$ violation using time-dependent asymmetries that is applicable at LHCb and $B$ factories, independent of entanglement and width difference assumptions.

Findings

Allows measurement of $T$ and $CPT$ violation in $B$ mixing.

Applicable at LHCb and $B$ factories without entangled states.

Does not require neglecting penguin pollution or assuming non-zero width difference.

Abstract

Quantum field theory, which is the basis for all of particle physics, requires that all processes respect $CPT$ invariance. It is therefore of paramount importance to test the validity of $CPT$ conservation. In this Letter, we show that the time-dependent, indirect $CP$ asymmetries involving $B$ decays to a $CP$ eigenstate contain enough information to measure $T$ and $CPT$ violation in $B^0$-${\bar B}^0$ mixing, in addition to the standard $CP$-violating weak phases. Entangled $B^0{\bar B}^0$ states are not required (so that this analysis can be carried out at LHCb, as well as at the $B$ factories), penguin pollution need not be neglected, and the measurements can be made even if the $B^0$-${\bar B}^0$ width difference vanishes.