Time reversal violation for entangled neutral mesons

J Bernabéu

doi:10.1088/1742-6596/447/1/012005

Abstract

A direct evidence for Time Reversal Violation (TRV) means an experiment that, considered by itself, clearly shows TRV independent of, and unconnected to, the results for CP Violation. No existing result before the recent BABAR experiment with entangled neutral B mesons had demonstrated TRV in this sense. There is a unique opportunity for a search of TRV with unstable particles thanks to the Einstein-Podolsky-Rosen (EPR) Entanglement between the two neutral mesons in B, and PHI, Factories. The two quantum effects of the first decay as a filtering measurement and the transfer of information to the still living partner allow performing a genuine TRV asymmetry with the exchange of "in" and "out" states. With four independent TRV asymmetries, BABAR observes a large deviation of T-invariance with a statistical significance of 14 standard deviations, far more than needed to declare the result as a discovery. This is the first direct observation of TRV in the time evolution of any system.

Highlights

I was asked by the organizers to report about the recent discovery of Time Reversal Violation (TRV) in the Entangled Neutral B-system and the conceptual basis for such observation
The significance of the T-violation signal is obtained from the CL contours assuming Gaussian errors, the result corresponds to a significance equivalent to 14 standard deviations, and constitutes a direct observation of T violation
A unique opportunity for bypassing the problem of T-symmetry tests in unstable particles is provided by the Einstein-Podolsky-Rosen Entanglement between the two neutral mesons in B, and Φ, factories

Summary

Introduction

I was asked by the organizers to report about the recent discovery of Time Reversal Violation (TRV) in the Entangled Neutral B-system and the conceptual basis for such observation. Not all tests of T-symmetry are ruled out for particles that decay, as long as ΔΓ is not needed for the observable asymmetry. This last association is the foundation of the experimental performance of the Time-Reversal Transformation for a transition of the neutral B-

Results

Conclusion