# Physics:Scaling variable

From HandWiki

One calls a scaling variable any variable allowing one to find an identical description of phenomena in different situations by expressing them in a suitable projection. Examples are the description of electromagnetic interactions in matter in terms of *L*/*X*_{0} where *X*_{0} is the radiation length, the probability distribution of multiplicities of produced particles which *scales* approximately if plotted in terms of ( KNO-distribution), and in particular the scaling variables in inclusive reactions ( Deep Inelastic Scattering Variables).

Deviations from exact scaling are called *scaling violations*.