Single charged-particle inclusive cross sections for photon, pion and kaon beams on hydrogen at the CERN-SPS are presented as functions ofpT andxF. Data cover the range 0.0
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This paper reports cross-section measurements for the ρ0 and K*(890) vector mesons produced in e+e− annihilation at s=29 GeV. The data, which were taken with the High Resolution Spectrometer operating at the SLAC colliding-beam facility PEP, correspond to an integrated luminosity of 291 pb−1. The measured multiplicities for fractional momentum x>0.05 are Nρ0=0.79±0.04 and NK*0(890)=0.53±0.04. The measured fragmentation functions agree well with the predictions of the Lund model and when extrapolated to threshold, the corresponding total multiplicities are Nρ0=0.90±0.05 and NK*0(890)=0.59±0.05.
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A full-kinematics measurement of the π − p→ π − p π 0 reaction in the incident π − momentum region from 295 to 450 MeV/ c is presented. The measurement was performed with the OMICRON spectrometer at the CERN synchrocyclotron.
Integrated cross section.
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NUCLEUS IS NUCLEAR PHOTOEMULSION. EVENT WITH A TOTAL CHARGE OF ALL SPECTATOR FRAGMENTS OF A PROJECTILE = 0.
NUCLEUS IS NUCLEAR PHOTOEMULSION. EVENT WITH A TOTAL CHARGET OF ALL SPECTATOR FRAGMENTS OF A PROJECTILE = 1.
NUCLEUS IS NUCLEAR PHOTOEMULSION.
We have measured dijet angular distributions at √s =1.8 TeV with the Collider Detector at Fermilab and the Tevatron p¯p Collider and find agreement with leading-order QCD. By comparing the distribution for the highest dijet invariant masses with the prediction of a model of quark compositeness, we set a lower limit on the associated scale parameter Λc at 330 GeV (95% C.L.).
Numerical values read from figure in preprint.
Production rates of multijet hadronic final states are studied ine+e− annihilation at 29 GeV center of mass energy. QCD shower model calculations with exact first order matrix element weighting at the first gluon vertex are capable of reproducing the observed multijet event rates over a large range of jet pair masses. The method used to reconstruct jets is well suited for directly comparing experimental jet rates with parton rates calculated in perturbative QCD. Evidence for the energy dependene of αs is obtained by comparing the observed production rates of 3-jet events with results of similar studies performed at higher center of mass energies.
Observed production rates relative to the total hadronic cross section.
Production rates corrected for fragmentation, initial state radiation and detector effects.
Inclusive charged particle production ine+e− annihilation into hadrons is studied in terms of the particle fractional momentumxp. Thexp distribution for gluon jets is extracted by comparing two data samples measured in the TASSO detector: nearly symmetric three jet events at centre-of-mass energyW∼35 GeV and two jet events atW∼22 GeV, yielding quark and gluon jets of similar energies (∼11.5 GeV). No significant difference is observed between quark and gluon jets. Monte Carlo models based on parton showers describe the trend and energy variation of the data better than a model with second order matrix element in αs.
2 JET data at sqrt(s) = 35 GeV.
3 JET data at sqrt(s) = 22 GeV.
Gluon jet data at sqrt(s) = 11.5 GeV.
We report on total cross section and forward backward charge asymmetry measurements of the reactione+e− → τ+τ− at centre of mass energies of 35.0 GeV and 42.4 GeV using the TASSO detector. Including previous data an analysis in terms of electroweak parameters of the standard model is presented, and lower limits on mass scale parameters of residual contact interactions are given. A combined analysis of electroweak couplings using all our results on leptonic reactionse+e−→l+l− has been performed.
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We report on an analysis of the multiplicity distributions of charged particles produced ine+e− annihilation into hadrons at c.m. energies between 14 and 46.8 GeV. The charged multiplicity distributions of the whole event and single hemisphere deviate significantly from the Poisson distribution but follow approximate KNO scaling. We have also studied the multiplicity distributions in various rapidity intervals and found that they can be well described by the negative binomial distribution only for small central intervals. We have also analysed forward-backward multiplicity correlations for different energies and selections of particle charge and shown that they can be understood in terms of the fragmentation properties of the different quark flavours and by the production and decay of resonances. These correlations are well reproduced by the Lund string model.
RATIO of MULT/DISPERSION for the whole event to that for the single hemisphere data.
Complete event multiplicities.
Single hemisphere multiplicities.
This paper reports results of a search for production by radiative e+e− annihilation of particles that interact only weakly in matter. The search has been made in a data set corresponding to 110 pb−1 acquired with the ASP detector at the Stanford Linear Accelerator Center storage ring PEP (√s =29 GeV). No anomalous signal has been observed, which limits the number of generations of light neutrinos to be Nν<7.9 (at 90% C.L.). Limits are also placed on the masses of particles predicted to exist by models of supersymmetry.
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