# Sanford-Wang parameterisation

Template:Orphan The Sanford-Wang parameterisation is an empirical formula used to model the production of pions in nuclear interaction of the form p+A → ${\displaystyle \pi ^{+}}$+X where a beam of high-energy protons hit a material.
Its formula for the double-differential cross section with respect to momentum (p) and solid angle (${\displaystyle \Omega }$) is as follows.
Where p and ${\displaystyle \theta }$ are the momentum of the outgoing pion and its angle from the direction of the incident proton. The numbers ${\displaystyle c_{1}\ldots c_{8}}$ are the Sanford-Wang parameters and are typically varied to give a good fit with experimental data.