In this experiment, a high-energy photon strikes a stationary chunk of beryllium. This collision occasionally results in the creation of a charmed meson (D0). Charmed mesons do not live very long before they decay into two other particles, a pion (π) and a kaon (K). The D0 has a lifetime of 4.0 x 10-13 s. They don't live long enough to travel very far through the detector--unless they are going very fast! This activity will help you to explore that very thing.
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