Mapping the Proton's Fluctuating Waistline

Understand

We discuss a mechanism for the apparently universal scaling in the high-multiplicity tail of charged particle distributions for high energy nuclear collisions.

• We argue that this scaling behavior originates from rare fluctuations of the nucleon density.
• We discuss a pair of simple models of proton shape fluctuations.
• A "fat" proton with a size of 3 fm occurs with observable frequency.