Measurements of the very-forward energy in pp collisions at the LHC and constraints for cosmic ray air showers
2019 August 30
The very-forward energy production in hadron collisions is of great importance for the understanding of ultra-high energy cosmic ray air showers. The CASTOR calorimeter of CMS is located at $-6.6<\eta<-5.2$ in a unique phase-space for this purpose; the characteristics of secondaries in this phase-space of hadron collisions have a determining impact on the formation of air shower cascades. We present the latest results of CASTOR including the first direct measurement of the ratio of electromagnetic to hadronic energy in the forward phase-space at the LHC. Possible implications of these results for cosmic ray physics are outlined.