Speaker: Prof. Dieter Roehrich (University ofBergen, Norway)
Time:  Dec.9, Tuesday, 10:30
Location:  Lecture Hall 9409

Abstract:

The parton structure of the nucleus at very low Bjorken-x, especially its gluon content, is largely unknow.  Measurements at small-x will not only provide experimental constrains for (nuclear) PDFs in a region of phasespace where experimental data is scarce, but will also enable the study of non-linear QCD effects such as gluon saturation. The scale at which saturation effects set in can be explored in the forward region of proton-proton and proton-nucleus collisions at the LHC. The ALICE Forward Calorimeter (FoCal) upgrade aims to investigate gluon PDFs down to Bjorken-x of ~10^-6 at a momentum transfer of Q ~ 4 GeV/c with direct photons. Positioned at very forward rapidities (3.4 < η < 5.8), FoCal will offer exceptional spatial resolution and ultra-fine granularity, making it uniquely capable of measuring direct photons, neutral mesons, and jets in a kinematic region sensitive to small-x gluons, as well as photo-production of vector mesons such as the J/psi in proton-Pb and Pb-Pb ultra-peripheral collisions.

Introduction: 

Dieter Roehrich, Professor for experimental nuclear physics at the University of Bergen in Norway. PhD from the Philipps-Universität Marburg, Germany, in 1986. Worked at the University of Frankfurt, BNL and CERN. Academician of the European Academy of Sciences (Academia Europaea) and Academician of the Norwegian Academy of Technological Sciences (NTVA). Research interests: ultra-relativistic nuclear collision, instrumentation, and medical physics. 

PPT or PDF file download:/FoCal_Wuhan_2025.pdf