B Meson Time Reversal Violation (image) DOE/SLAC National Accelerator Laboratory 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 Usage Restrictions Credit required Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.