Physics potential of the CMS CASTOR forward calorimeter

The CASTOR calorimeteris a detector covering the very forward region of the CMS experiment at the LHC. It surrounds the beam pipe with 14 longitudinal modules each of which consisting of 16 azimuthal sectors and allows to reconstruct shower profiles, separate electrons and photons from hadrons and search for phenomena with anomalous hadronic energy depositions. The physics program that can be performed with this detector includes a large variety of different QCD topics. In particular, the calorimeteris supposed to contribute to studies of low-x partondynamics, diffractive scattering, multi- partoninteractions and cosmic ray related physics in proton-proton and heavy-ion collisions. The physics capabilities of this detector are briefly summarized in this paper.