Study of electron pair production below the Z mass at the CERN pp collider UA2 Collaboration Bern-Cambridge-CERN-Dortmund-Heidelberg-Melbourne-Milano-Orsay (LAL)-Pavia- Perugia-Pisa-Saclay (CEN)

Results on the cross section for the production of electron pairs in pp collisions at x/~--630 GeV are presented. The measured value is a= 405 + 51 (syst.) _+ 84 (syst.) pb, in the invariant mass interval 10 < m < 70 GeV. The results are compared to recent theoretical calculations which include O(o~ 2 ) QCD contributions. The comparison of these data with those of lower energy experiments show approximate scaling as a function of the variable x/z= m/x~ss

The detection of neutrino interactions in the emulsion/lead target of the OPERA experiment

The OPERA neutrino detector in the underground Gran Sasso Laboratory (LNGS) was designed to perform the first detection of neutrino oscillations in appearance mode through the study of \u3bd\u3bc\u2192 \u3bd\u3c4 oscillations. The apparatus consists of an emulsion/lead target complemented by electronic detectors and it is placed in the high energy long-baseline CERN to LNGS beam (CNGS) 730 km away from the neutrino source. Runs with CNGS neutrinos were successfully carried out in 2007 and 2008 with the detector fully operational with its related facilities for the emulsion handling and analysis. After a brief description of the beam and of the experimental setup we report on the collection, reconstruction and analysis procedures of first samples of neutrino interaction event