D. Allasia

Inelastic J / psi production in deep inelastic scattering from hydrogen and deuterium and the gluon distribution of free nucleons

We present results on inelastic J/PSI-production from muon interactions with hydrogen and deuterium at an incident muon energy of 280 GeV. The measured cross section ratio per nucleon for muon-indu ...

Measurement of the neutron and proton structure functions from neutrino and antineutrino scattering in deuterium

Abstract Data from an exposure of the BEBC bubble chamber filled with deuterium to neutrino and antineutrino wide band beams have been used to extract the x dependence of the structure functions for scattering on protons and neutrons and the fractional momentum distributions of the valence quarks and the antiquarks of different flavours. The difference F n 2 − F p 2 is compared with recent data from high energy μD scattering. A result is also obtained on the sum rule giving the difference between the number of up and down quarks in the nucleon.

Measurement of the neutron and the proton F2 structure function ratio

The ratio of the structure function F2n/F2p (x) has been measured in deep inelastic scattering of 274 GeV muons on hydrogen and deuterium targets exposed simultaneously to the beam. The results were obtained from 0.3 (0.6) million events from hydrogen (deuterium) in the range 0.004 <x< 0.8 and 1 <Q2< 190 GeV2. At x < 0.25 both the statistical and the systematic error is below 2%. Implications for parton distributions and for the σw/σz production cross section ratio in pp collisions are discussed. When compared to other results obtained at lower energies, the data indicate a Q2 dependence of the ratio.

Q2 dependence of the proton and neutron structure functions from neutrino and antineutrino scattering in deuterium

Abstract12,100 νD and 10,500

INCLUSIVE rho0 PRODUCTION IN anti-muon-neutrino D AND muon-neutrino D CHARGED CURRENT INTERACTIONS.

\bar vD

SEARCH FOR A DELTA(1236)-DELTA(1236) STRUCTURE OF THE DEUTERON

charged current interactions in deuterium measured in the BEBC bubble chamber were used to obtain the complete set of structure functions of proton and neutron. Thex andQ2 dependence of the structure functions of up and down valence quarks and antiquarks are presented and discussed. The Adler and Gross-Llewellyn Smith sum rules have been tested at differentQ2 values. A QCD analysis of the four non singlet structure functionsxF3νN,xuv,xdv andF2νn−F2νp has been performed yielding values ofΛLO between 100 and 300 MeV.

Measurement of the νμ and νμ nucleon charged-current total cross sections, and the ratio of νμ neutron to νμ proton charged-current total cross sections

Abstract An analysis has been performed of neutrino and antineutrino interactions with protons and neutrons in a deuterium bubble chamber. The interactions under study are quasielastic neutrino-neutron scattering and one-, two- and three-pion production reactions. Results are presented on cross sections, effective mass distributions, resonance production, momentum transfer distributions and coefficients of the decay angular distributions. Where possible, comparisons are made with existing theoretical models and predictions.

Measurement of the neutral current coupling constants in neutrino and antineutrino interactions with deuterium

Abstract Inclusive production of the meson resonance ϱ0 in high-energy neutrino and antineutrino charged current (CC) interactions in deuterium was studied using the bubble chamber BEBC exposed to the CERN-SPS wide band neutrino and antineutrino beams. In a sample of 10693 charged current ν μ D and 13 758νμD interactions we found 0.222 ± 0.014ϱ0 per charged current event. Thr production of f mesons is smaller than 0.03 per CC event (90% confidence level). The ϱ0 production properties are studied in terms of charged hadron multiplicity, of the mass of the hadronic system and of various kinematical variables. The experimental results are compared with the predictions of the Lund fragmentation model, whose predictions are about 50% higher than the experimental values.