# Tag Info

The differential cross section: $$\frac{\text{d}\sigma(p\bar p \to \gamma\cdots)}{\text{d} p_T^\gamma}$$ is proportional to a probability density function (pdf) for the transverse momentum of the photon $p_T^\gamma$. In fact, if a photon is produced in the above process, the pdf for its transverse momentum would be  p(p_T^\gamma) = ...