Publication at Faculty of Mathematics and Physics |
2010
Abstract
A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c.
The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons.
The muon critical energy in lead tungstate is measured to be 160+5/-6 plus or minus 8 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy.