Nuclear Physics Colloquium Nuclear Physics Colloquium Location:
Physics Building Science Campus Riedberg, Max-von-Laue-Str. 1,
room PHYS 2.116
Time: Monday, December 9, 2013,
3:00-4:00pm (plus 10min for discussion)
Contact: hees@fias.uni-frankfurt.de
Studies of the hard exclusive processes allowed for the first time to measure the three dimensional structure of fast nucleons – the $x$-dependent transverse single parton distributions in the nucleon. This puts strong restrictions on the description of proton-proton interactions at the LHC and in particular on some of the parameters of the Monte Carlo models of pp interactions. Several features of the underlying events in hard collisions follow from this geometry while considerations of the S-channel unitarity leed to a number of challenging questions about the origin of non-linear effects. An explanation is suggested of the long standing puzzle of the high rate of multiparton interactions as due to the pQCD induced correlations. Evidence for the presence of the fluctuations of the gluon density in nucleons as well as fluctuations of the overall strength of the interactions are presented and implications for pA collisions are outlined. The kinematic range where interaction of fast partons of the projectile with the target reaches black disk regime strength is estimated. Implications for forward hadron production are briefly discussed.