New parton distribution functions for the photon Original Research Article

We present new improved parton distributions for the photon. We fit all available data on the photon structure function, F2γ (x, Q2), with Q2 ⩾ 3 GeV2, in order to determine the quark distributions. We also pay particular attention to the gluon distribution in the photon, gγ(x),Q2) which has been poorly constrained in earlier analyses which only include structure function data. We use large PT jet production in yy collisions from TRISTAN to constrain gγ. We also see what information can be gleaned from yp collisions at HERA on gγ and on the quark distributions at large x, where there are no structure function data. We review future prospects of elucidating the parton distributions of the photon.