M. Monteno

Study of the isospin symmetry breaking in the light quark sea of the nucleon from the Drell-Yan process

Abstract The ratio of cross-sections for muon pair production through the Drell-Yan process in p − p and p − d reactions has been measured at y ≈ 0, with 450 GeVc incident protons. The asymmetry A DY = δ pp − δ pn δ pp +δ pn amounts to −0.09 ± 0.02 ± 0.025. The ratio u d of the nucleon sea structure functions derived from this measurement amounts to 0.51 ± 0.04 ± 0.05 at x = 0.18 and suggests that isospin symmetry is broken in the light quark sea of the nucleon.

Observation of a threshold effect in the anomalous J/ψ suppression

Abstract We report on a search for a phase transition from ordinary nuclear matter to a state of deconfined quarks and gluons as predicted by lattice QCD calculations. A new measurement of charmonium production in Pb-Pb interactions at 158 GeV/ c per nucleon agrees with our previous results and confirms the anomalous J/ ψ suppression we had already observed on a significantly smaller data sample. New event selection and analysis techniques show that, for peripheral collisions, the J/ ψ cross-section per nucleon-nucleon collision agrees with the precise suppression pattern inferred from a wide range of measurements extending from p-p up to S-U collisions. As the collisions become more central, the Pb-Pb cross-section exhibits a clear departure from this normal behaviour. The onset of the anomalous J/ ψ suppression reported here is the first clear observation of a threshold effect in heavy ion collisions and can be considered as a strong indication of the production of a deconfined quark-gluon phase in central Pb-Pb collisions.

Charmonium production and nuclear absorption in p-A interactions at 450 GeV

Abstract.The production of

Transverse momentum distributions of J/ψ, ψ′, Drell–Yan and continuum dimuons produced in Pb–Pb interactions at the SPS

{\rm J}/\psi

Study of penetrating cosmic ray muons and search for large scale anisotropies at the Gran Sasso Laboratory

and

J/ψ, ψ′ and Drell-Yan production in pp and pd interactions at 450 GeV/c

\psi^\prime

Results on leptonic probes from NA50

charmonium states in proton-nucleus interactions has been investigated by the NA50 experiment, at the CERN SPS. High statistics data sets were collected with collisions induced by 450 GeV protons incident on Be, Al, Cu, Ag and W targets. The

ATMOSPHERIC NEUTRINO OSCILLATIONS WITH THREE NEUTRINOS AND A MASS HIERARCHY

{\rm J}/\psi

Transverse momentum distribution of J/Ψ produced in PbPb and p-A interactions at the CERN SPS

and

Charmonia absorption in p-A collisions at the CERN SPS results and implications for PbPb interactions

\psi^\prime