Ch. Berger

Observation of a Narrow Resonance Formed in e+ e- Annihilation at 9.46-GeV

Abstract An experiment using the PLUTO detector has observed the formation of a narrow, high mass, resonance in e+e− annihilations at the DORIS storage ring. The mass is determined to be 9.46±0.01 GeV which is consistent with that of the Upsilon. The gaussian width σ is observed as 8±1 MeV and is equal to the DORIS energy resolution. This suggests that the resonance is a bound state of a new heavy quark-antiquark pair. An electronic width Γee=1.3±0.4 keV was obtained. In standard theoretical models, this favors a quark charge assignment of 1 3 .

Study of atmospheric neutrino interactions with the Fréjus detector

Abstract We present an analysis of the neutrino event sample recorded in the Frejus experiment. This sample which corresponds to the 1.56 kt yr final sensitivity of the experiment is compared to the predictions of a Monte Carlo neutrino simulation program. It is based on a recent calculation of the atmospheric neutrino flux at the Frejus latitude which takes into account muon polarization effects. The comparison is performed on the distributions of the visible energy, the zenith angle and the neutrino flavor. Good agreement is obtained between the data and the simulation within statistics.

First observation of hadron production in e+e− collisions at 13 and 17 GeV CMS energy with the pluto detector at petra: Pluto Collaboration

Abstract First results from the magnetic detector PLUTO at the new e + e − storage ring PETRA are shown. The ratio R of the cross section for hadron production to that for μ-pair production has been measured to be R = 5.0 ± 0.5 at 13 GeV and 4.3 ±0.5 at 17 GeV. Both values have an additional systematic error of 20%. The events show a typical 2-jet structure. The mean transverse momentum approaches a constant value with increasing energy implying a shrinkage of the jet opening angle.

Measurement of F-2(c(c)over-bar) and F-2(b(b)over-bar) at high Q(2) using the H1 vertex detector at HERA

Abstract.Measurements are presented of inclusive charm and beauty cross sections in e + p collisions at HERA for values of photon virtuality Q2 > 150 GeV2 and of inelasticity 0.1 < y < 0.7. The charm and beauty fractions are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 vertex detector. The data are divided into four regions in Q2 and Bjorken x, and values for the structure functions

The Fréjus nucleon decay detector

F_2^{c\bar{c}}

A study of multi-jet events in e+e− annihilation

and

Jet analysis of the ϒ(9.46) decay into charged hadrons

F_2^{b\bar{b}}

Search for single top quark production in ep collisions at HERA

are obtained. The results are found to be compatible with the predictions of perturbative quantum chromodynamics.

Measurement and QCD analysis of the photon structure function F2(x, Q2)

Abstract The characteristics, trigger and monitoring systems, data acquisition as well as the performance of the Frejus nucleon decay detector are presented.

Inclusive dijet production at low Bjorken-x in deep inelastic scattering

Abstract A multi-jet analysis of hadronic final states from e + e − annihilation in the energy range 27 E cm S = 0.15 ± 0.03 (stat. error) ± 0.02 (syst. error). The inferred energy distribution of the most energetic parton is in good agreement with the first-order QCD prediction. A scalar-gluon model is strongly disfavoured. Higher-twist contributions to the three-jet sample are found to be small.