Transverse Energy Measurement in Heavy Ion Collisions with CMS

Possibilities of the transverse energy measurement in Pb-Pb and Ca-Ca collisions at LHC with CMS detector are studied. It is shown that the CMS calorimeters are well adapted for this measurement. The detected transverse energy strongly depends on the impact parameter, thus allowing one to measure the centrality of the collisions. For central Pb-Pb and Ca-Ca interactions, about 86% of generated transverse energy will be detected by the CMS calorimeters. For peripheral events, the fraction of detected transverse energy is slightly less, about 82% for Pb-Pb and 76% for Ca-Ca collisions.