Parton content of virtual photons
Parton content of virtual photons
The parton content of virtual transverse photons \ensuremath{\gamma}(${\mathit{P}}^{2}$) is expressed in terms of perturbative pointlike and nonperturbative hadronic (VMD) components. The resulting LO and NLO parton distributions ${\mathit{f}}^{\ensuremath{\gamma}(\mathit{P}2}$)(x,${\mathit{Q}}^{2}$) are smooth in ${\mathit{P}}^{2}$. They apply uniformly to all ${\mathit{P}}^{2}$\ensuremath{\ge}0 whenever \ensuremath{\gamma}(${\mathit{P}}^{2}$) is probed at a scale ${\mathit{Q}}^{2}$\ensuremath{\gg}${\mathit{P}}^{2}$ where the transverse photons …