We report new results on a precision measurement of the ratio R=σLσT and the structure function F2 for deep-inelastic electron-nucleon scattering in the kinematic range 0.2≤x≤0.5 and 1≤Q2≤10 (GeV/c)2. Our results show, for the first time, a clear falloff of R with increasing Q2. Our R and F2 results are in good agreement with QCD predictions only when corrections for target-mass effects are included.
2.6 pct rad length target.
2.6 pct rad length target.
2.6 pct rad length target.
The charged particle multiplicity distributions for two-jet events ine+e− annihilation at 29 GeV have been measured using the High Resolution Spectrometer at PEP. A Poisson distribution describes the data for both the complete event and for the single jets. In addition, no correlation is observed between the multiplicities in the two jets of an event. For fixed values of the prong number of the complete event, the multiplicity sharing between the two jets is in good agreement with a binomial distribution. The rapidity gap distribution is exponential with a slope equal to the mean rapidity density. These observations, which are consistent with a picture of independent emission of single particles, are contrasted to the results from soft hadronic collisions and conclusions are drawn about the nature of clusters.
Charged Particle Multiplicity distributions for single jet and whole event from the two jet sample. The numerical values are given in the paper Derrick et al, PR D34 (86) 3304, and are coded in this database as (<a href=http://durpdg.dur.ac.uk/scripts/reacsearch.csh/TESTREAC/red+1437> RED = 1437 </a>).
Single Jet Mean Multiplicities.
Total event charged multiplicities.
η production has been investigated by the Mark II collaboration at the SLAC e+e− storage ring PEP. η particles are reconstructed by their γγ decay mode. The η fragmentation function has been measured and found to be in good agreement with the Lund-model prediction. η′ production has been measured for the first time in high-energy e+e− annihilation. There is evidence at the 3σ level for Ds± decay into ηπ± and η′π±.
Numerical values supplied by G.Wormser.
Z = 0.0 point extrapolated using LUND fragmentation model.
Z = 0.0 point extrapolated using LUND fragmentation model.
Measurements of inclusive transverse-momentum spectra for charged particles produced in proton-antiproton collisions at √2 of 630 and 1800 GeV are presented and compared with data taken at lower energies.
No description provided.
No description provided.
Results of fit to invariant cross section of the form AP0**N/(PT + P0)**N.
A search for multihadronic events produced with two energetic leptons has been performed at PETRA using 130 pb −1 accumulated by the CELLO detector at 35 GeV ⩽ √ s ⩽46.8 GeV. Three μ + μ − , eleven e + e − and three eμ events were observed. The mesured yields an dthe event characteristics are in good agreement with the expectation for the α 4 QED processes e + e − → ℓ + ℓ − q q and from semileptonic decays of pairs of heavy quarks.
No description provided.
Transverse-energy distributions have been measured for the collisions of the 32 S nucleus with Al, Ag, W, Pt, Pb, and U target nuclei, at an incident energy of 200 GeV per nucleon. The shapes of these distribution reflect the geometry of the collisions, including the deformation effects. For central collisions, the transverse-energy production in the region −0.1< η lab <2.9 increases approximately as A 0.5 , where A is the atomic mass number of the target. This increase is accompanied by a relative depletion in the forward region η lab > 2.9. These results are compared with those obtained under similar conditions with incident 16 O nuclei. A comparison is also made with the predictions of a Monte Carlo generator based on the dual parton model. Finally, we give estimates of the energy density reached and its dependence on the atomic mass number of the projectile.
No description provided.
No description provided.
No description provided.
A search for pairs of highpT prompt photons produced in hydrogen by a 280 GeV/c incidentπ- beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forpT>3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of αs is also presented.
PT is the transverse momentum of either of the two photons.
PT is the transverse momentum of either of the two photons.
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No description provided.
No description provided.
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The π − yield in the momentum range 500–740 MeV/ c produced by 800 MeV protons incident on targets of Be and C has been measured at laboratory production angles between 0° and 20°. The yield of 725 MeV/ c π − from Be and C at 0° is a factor of 6 greater than at 20°, for 600 MeV/ c π − the factor is 3. The yield from beryllium is typically 30% higher than from carbon.
No description provided.
No description provided.
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