Cross section (physics)

Probability of a given process occurring in a particle collision

In physics, the cross section is a measure related to the probability that a specific process will take place in a collision of two particles. For example, the Rutherford cross section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus. Cross section is typically denoted σ (sigma) and has dimension of area, with units of square meter or more often in barns.

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