J/ψ and γ Photoproduction in Pb-Pb Collisions at Large Hadron Collider

Hard photoproduction of J/ψ and γ at large hadron collider Pb-Pb collisions with center of mass energy 6300AGeV is discussed in the process Pb + Pb → Pb + J/ψ(Γ) + X with three types of equivalent photon spectrum function. It turns out that in hard photoproduction the J/ψ cross section is dominated by the gluon and heavy quark fragmentation, especially the gluon fragmentation is very important at large p_t, while the γ cross section is dominated by the leading order process. It may be conclude from the result that the hard photoproduction processes can be used to test several important problems such as the gluon distribution in the nucleus, gluon and heavy quark fragmentation of J/ψ, and so on. In addition the process also provide a new way of testing the EMC effects.