Giles Barr

Abstract:

The NA48 collaboration is preparing a new experiment at CERN aiming to study CP violation in the K0-K0 system with an accuracy of 2 × 10-4 in the parameter ℛe(∈′/∈). Decays in two π0's will be recorded by a quasi-homogeneous liquid krypton calorimeter. A liquid krypton calorimeter has been chosen to combine good energy, position and time resolution with precise charge calibration and long-term stability. The prototype calorimeter incorporating the final design of the electrode read-out structure is presented in this paper. An energy resolution of ≃3.5%/√E with a constant term smaller than 0.5% has been obtained. The time resolution was found to be better than 300 ps above 15 GeV.

Abstract:

The Soudan 2 experiment has performed time-coincident cosmic ray air shower and underground muon measurements. Comparisons to Monte Carlo predictions show that such measurements can make statistically significant tests of the primary composition in the knee region of the cosmic ray spectrum. The results do not support any significant increase in the average primary mass with energy in the range of 104 TeV per nucleus. Some systematic uncertainties remain, however, particularly in the Monte Carlo modeling of the cosmic ray shower. © 1995 The American Physical Society.