2 research outputs found
Construction and test of a fine-grained liquid argon preshower prototype
A separate liquid argon preshower detector consisting of two layers featuring a fine granularity of 2.5~10 was studied by the RD3 collaboration. A prototype covering approximately 0.8 in pseudo-rapidity and 9 degrees in azimuth was built and tested at CERN in July 94. CMOS and GaAs VLSI preamplifiers were designed and tested for this occasion. The combined response of this detector and an accordion electromagnetic calorimeter prototype to muons, electrons and photons is presented. For minimum ionizing tracks a signal-to-noise ratio of 4.5 per preshower layer was measured. Above 150~GeV the space resolution for electrons is better than 250~m in both directions. The precision on the electromagnetic shower direction, determined together with the calorimeter, is better than 4 mrad above 50~GeV. It is concluded that the preshower detector would adequately fulfil its role for future operation at CERN Large Hadron Collider
PII: 0370-2693(87)90325-X
The invariant mass distribution of jet pairs observed in the UA2 central calorimeter is examined in the search for an excess of events in the region of the W -+ and Z bosons, which would reveal their decays into quark-antiquark pairs. We give a detailed account of the methods of analysis used to optimize the mass resolution achieving ~ + 10%. A structure is observed at the level of = 3 standard deviations in the mass region of W ± and Z with shape and position consistent with expectation from their qft decays. It contains 632 + 190 events, 1.4 standard deviations above the standard model prediction of 340 + 80 events. On leave from Scuola Norrnal