FIRST EXPERIENCE AND RESULTS FROM THE HERA-B VERTEX DETECTOR SYSTEM

The HERA-B collaboration is building a detector to realize the ambitio us goal of observing CP violation in decays of neutral B-mesons. A cen tral element of the apparatus is the silicon vertex detector used to s electively trigger on these decays in a high charged particle multipli city background environment and to reconstruct secondary vertices from such decays with high precision. The vertex detector, the supporting infrastructure and first results using prototype detectors are describ ed. Results include imaging of the proton interaction region on the HE RA-B target, hit distributions in the detector planes, and alignment o f the detectors with each other and the target. (C) 1998 Elsevier Scie nce B.V. All rights reserved.