Recent Results on T and CP Violation at BABAR

TL;DR

This paper reports the first direct observation of time-reversal violation in the B-meson system using data from the BABAR experiment, complementing previous CP violation findings and confirming fundamental symmetry principles.

Contribution

The study provides the first direct evidence of TRV in B-mesons, utilizing a large dataset from BABAR to measure symmetry violations directly.

Findings

First direct observation of TRV in B-mesons

Confirmation of CPV and TRV relationship via CPT theorem

Large dataset enabled precise symmetry violation measurements

Abstract

CP-violation (CPV) and Time-reversal violation (TRV) are intimately related through the CPT theorem: if one of these discrete symmetries is violated the other one has to be violated in such a way to conserve CPT. Although CPV in the B0-B0 system has been established by the B-factories, implying indirectly TRV, there is still no direct evidence of TRV. We report on the observation of TRV in the B-meson system performed with a dataset of 468 million BB pairs produced in Y(4S) decays collected by the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory. We also report on other CPV measurements recently performed on the B-meson system.