Speaker
Description
Ultra-Peripheral Pb-Pb collisions, in which the two nuclei pass close to each other but at an impact parameter larger than the sum of their radii, provide information about the initial state of nuclei. In particular, J/Psi production in such collisions proceeds by photon-gluon interactions, and is sensitive to the nuclear gluon distribution. The ALICE collaboration has published measurements of UPC J/Psi production in LHC Run 1 at both forward and mid-rapidity, and has obtained a substantially larger data set in 2015 from LHC Run 2. The increased statistics has allowed a more precise study, and the higher collision energy means that lower values of Bjorken-x can be probed. In this study the first physics results from Run 2 on this channel will be presented.
