Forward physics with CASTOR and TOTEM at CMS
Many limitations in understanding important aspects of hadron collisions become most visible in the forward phase space at colliders. This is where the contributing physics is most soft, however, at the same time the energy transport is by far largest. This is why this region is in particular important for astroparticle physics. The CASTOR calorimeter at CMS has performed a series of measurements up to 13TeV. In this presentation we review the data and draw conclusions on the model performance and potential impact on understanding of hadron collisions. Furthermore, also the combined measurements of TOTEM+CMS are presented and discussed.