The NA48 liquid-krypton calorimeter

摘要

The NA48 experiment at CERN was primarily designed to measure the value of Re(epsilon'/epsilon), the parameter of direct CP-violation, from two-pion decays in simultaneous K-L(0) and K-S(0) beams produced at two different targets. Data for this measurement were taken from 1997 to 2001. The value obtained from the data taken in 1997-1999 is Re(epsilon'/epsilon) (15.3 +/- 2.6) x 10(-4) (Eur. Phys. J. 22 (2001) 231). The remaining data are being analyzed at present. In 2002 and the following years, rare-decay and CP-violation studies will be made in a high-intensity K-S(0) beam (CERN/SPSC 2000-002) and in simultaneous beams of charged kaons (CERN/SPSC 2000-003), using basically the same apparatus. Photons from neutral-pion decays are detected by a liquid-krypton calorimeter. For the Re(epsilon'/epsilon) measurement it is very important to suppress the huge background from K-L(0) --> 3pi(0) decays, which requires very good spatial, energy and L time resolution. (C) 2002 Elsevier Science B.V. All rights reserved. References: 4