[1] CERN, CH-1211 Geneva, Switzerland
[2] LIP, P-1000 Lisbon, Portugal
[3] Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland
[4] Aalto Univ, Low Temp Lab, FI-02150 Espoo, Finland
[5] Univ Karlsruhe, IEKP, D-76128 Karlsruhe, Germany
[6] Univ Florence, Dipartimento Energet, I-50139 Florence, Italy
[7] Univ Bern, LHEP, CH-3012 Bern, Switzerland
[8] Univ Naples Federico II, Dipartimento Fis, I-80125 Naples, Italy
[9] Ist Nazl Fis Nucl, I-80125 Naples, Italy
[10] Univ Geneva, Dept Radiol, CH-1211 Geneva, Switzerland
[11] Jozef Stefan Inst, Exp Particle Phys Dept, Ljubljana 1001, Slovenia
[12] Brunel Univ, Uxbridge UB8 3PH, Middx, England
[13] Brookhaven Natl Lab, Upton, NY 11973 USA
[14] Russian Acad Sci, AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia
[15] Tech Univ Munich, Phys Dept E18, D-85748 Garching, Germany