QCD multiple scattering and nuclear dependence in
high energy nuclear collisions
Jianwei Qiu, Iowa State University
Abstract:
Nuclear dependence is an excellent probe of nuclear structure and
dynamical properties of strong interacting medium produced in
high energy nuclear collisions. Understanding the features of
different sources of nuclear dependence is extremely important
for discovering and learning new properties of QCD and strong
interaction physics. In this talk, I will discuss the close
connection between QCD partonparton multiple scattering and
nuclear dependence in high energy nuclear collisions. I will
present a systematic calculation of the universal (process
independent) nuclear dependence to nuclear parton distribution
functions (nPDFs), and show that coherent QCD multiple scattering
significantly modifies the gluon distribution and its evolution
at small$x$ and low $Q^2$. To explore the effect of QCD
multiple scattering in hadornic collisions, I will present a
recent calculation for transverse momentum broadening of heavy
vector bosons production, and discuss why the broadening could
be smaller in hot dense medium than in cold nuclear matter.
Finally, I will make some predictions for the broadening
at the LHC energies.
