Solution to the Sudakov suppressed Balitsky-Kovchegov equation and its application to HERA data

We analytically solve the Sudakov suppressed Balitsky-Kovchegov evolution equation with fixed and running coupling constants in the saturation region. The analytic solution of the S-matrix shows that the exp(-O(η^2))rapidity dependence of the solution with the fixed coupling constant is replaced by the exp(-O(η^3/2))dependence in the smallest dipole running coupling case, as opposed to obeying the law found in our previous publication, where all the solutions of the next-to-leading order evolution equations comply with exp(-O(η))rapidity dependence once the QCD coupling is switched from the fixed coupling to the smallest dipole running coupling prescription. This finding indicates that the corrections of the sub-leading double logarithms in the Sudakov suppressed evolution equation are significant, which compensate for a part of the evolution decrease of the dipole amplitude introduced by the running coupling effect. To test the analytic findings, we calculate the numerical solutions of the Sudakov suppressed evolution equation, and the numerical results confirm the analytic outcomes. Moreover, we use the numerical solutions of the evolution equationto fit the HERA data. This demonstrates that the Sudakov suppressed evolution equation can achieve a good quality fit to the data.

Centrality Dependence of Charmed-Meson Photoproduction in Ultrarelativistic Heavy Ion Collisions

We calculate the centrality dependence of inclusive cross section of large-p _(T )charmed-meson(D^0,D~*,D^(*+),and D_s^+)from heavy quark fragmentation by the hard photoproduction processes in ultrarelativistic heavy ion collisions.The numerical results indicate that the contribution of the hard photoproduction processes cannot be negligible for the inclusive charmed-meson production in Au-Au collisions at Relativistic Heavy Ion Collider(RHIC)and Pb-Pb collisions at Large Hadron Collider(LHC).