Abstract
Although violation in the meson system has been well established by the factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral mesons into definite flavor states ( or ), and or final states (referred to as or ), allow comparisons between the probabilities of four pairs of -conjugated transitions, for example, and , as a function of the time difference between the two decays. Using pairs produced in decays collected by the BABAR detector at SLAC, we measure -violating parameters in the time evolution of neutral mesons, yielding and . These nonzero results represent the first direct observation of violation through the exchange of initial and final states in transitions that can only be connected by a -symmetry transformation.
- Received 24 July 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.211801
© 2012 American Physical Society
Viewpoint
Particle Decays Point to an Arrow of Time
Published 19 November 2012
An experiment studying B meson decays makes a direct observation of time-reversal violation without relying on assumed relationships with other fundamental symmetries.
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