A precise measurement of 180 GeV muon energy losses in iron

The energy loss spectrum of 180 GeV muons has been measured with the 5.6 m long finely segmented Module 0 of the ATLAS hadron Tile Calorimeter at the CERN SPS. The differential probability dP/d nu per radiation length of a fractional energy loss nu = DeltaE(mu)/E-mu has been measured in the range 0.025 less than or equal to nu less than or equal to 0.97: it is compared with theoretical predictions for energy losses due to bremsstrahlung, production of electron-positron pairs. and energetic knock-on electrons. The iron elastic form factor correction Delta (el)(Fe) = 1.63 +/-0.17(stat)+/-0.23(syst)+/- (0.20)(0.14theor) to muon bremsstrahlung in the region of no screening of the nucleus by atomic electrons has been measured for the first time, and is compared with different theoretical predictions. RI David, Mario/C-4664-2012; Flix, Josep/G-5414-201

A measurement of the photonuclear interactions of 180 GeV muons in iron

The energy spectrum and the cross section of photonuclear interactions of 180 GeV muons in iron were measured at the CERN SPS using prototype modules of the ATLAS hadron calorimeter. The differential cross section (N-A/A)nudsigma/dnu for a union fractional energy loss nu = E-mu/E-mu was measured in the range 0.1 < nu < 1. The integrated cross section (N-A/A) integral(0.1)(1) nudsigma/dnu is (0.26 +/- 0.03(stat) +/- 0.03(syst)) . 10(-6) cm(2) g(-1) in agreement with the theoretical prediction of 0.267 . 10(-6) cm(2)g(-1). The best adjustment of the data to the theory is achieved for the value of sigma(gamma)N = (115 +/- 18(stat) +/- 15(syst))mub of the photon-nucleon cross section for photons with energies in the range from 18 to 180 GeV