Muon-induced background to proton decay in the p → K + ν decay channel with large underground liquid argon TPC detectors

摘要

Large liquid argon TPC detector programs such as LBNE and LAGUNA-LBNO will be able to make measurements of the proton lifetime which will outperform Cherenkov detectors in the proton decay channel p → K + ν . At the large depths which are proposed for such experiments, a non-negligible source of isolated charged kaons may be produced in the showers of cosmogenic muons. We present an estimate of the cosmogenic muon background to proton decay in the p → K + ν channel. The simulation of muon transport to a depth of 4 km w.e. is performed in the MUSIC framework and the subsequent propagation of muons and secondary particles in the vicinity of a cylindrical 20 kt LAr target is performed using Geant 4. An exposure time of 100 years is considered, with a rate of 0.0012 events/kt/year at 90% CL predicted from our simulations.