By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium.

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We report on the first observation of neutrino induced production of muon pairs in the electromagnetic field of a nucleus. The data has been obtained using the CHARM II detector exposed to the CERN wideband neutrino and antineutrino beams. A clear signal of 55 +/- 16 events is seen in a sample of dimuons of opposite charge without visible recoil at the vertex. The cross section is determined and found to be in agreement with the standard model prediction

We report on a study of the dierential cross sections d=dy for the processes of elastic -and -electron scattering. The data on which this analysis is based were recorded between 1987 and 1990 with the CHARM II detector in the wide band neutrino beam at the CERN-SPS. For the rst time the shapes of these y-distributions have been determined in a modelindependent w a y . A t to the data yields for the squares of the neutral coupling constants the ratio g 2 R =g 2 L = 0 : 60 0:19 (stat:) 0:09 (syst:).