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Contact: Bronwyn Barnett
DOE/SLAC National Accelerator Laboratory

B Meson Time Reversal Violation

Caption: We depict the process of transformation from one type of B meson into another type as time progresses, illustrated here as a red B turning into a blue B. When the process is time-reversed, represented by a reversed clock, a blue B turns into a red B. Almost all subatomic processes are expected to be time-symmetric: the rates of transformation are the same regardless of whether the process is run forward or in reverse. The high-energy physics experiment known as BaBar is the first to measure a subatomic process in both forward and reverse and to observe a violation of this time symmetry: the blue to red transformation in the figure occurs at a different rate compared to the red to blue transformation.

Credit: Greg Stewart/SLAC National Accelerator Laboratory

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Related news release: BaBar experiment confirms time asymmetry

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