Proton-antiproton elastic scattering at CM energy 540 GeV has been studied in the t -range 0.04 < − t < 0.45 GeV 2 . The data are well fitted by the form exp ( bt ) with b = 17.1 ± 1.0 GeV −2 for | t | = 0.04 − 0.18 GeV su 2 and b = 13.7 ± 0.2 ± 0.2 GeV −2 for | t | = 0.21−0.45 GeV 2 . A luminosity measurement combined with the optical theorem gives σ tot = 67.6 ± 5.9 ± 2.7 mb and σ e1 / σ tot = 0.209 ± 0.018 ± 0.008.
No description provided.
No description provided.
ELASTIC RATIO ASSUMES RHO=0.
A sample of 52 Intermediate Vector Boson decays in the ( v e e) channel is described. They were produced at the CERN SPS Collider for an integrated luminosity of 0.136 pb −1 . Both production and decay properties fit well with expectations from the Standard Model of weak interactions. An improved value for the W mass is given and compared with the previously published value for the Z 0 mass.
No description provided.
Muons of high transverse momentum p μ T have been observed in the large drift chambers surrounding the UA1 detector at the CERN 540 GeV pp̄ collider. For an integrated luminosity of 108 nb −1 , 14 isolated muons have been found with p T > 15 GeV/ c . They are correlated with a large imbalance in total transverse energy, and show a kinematic behaviour consistent with the muonic decay of the Intermediate Vector Boson W ± of weak interactions. The partial cross section is in agreement with previous measurements for electronic decays and with muon-electron universality. The W mass is determined to be m W = 81 +6 −7 GeV/ c 2 .
No description provided.
The production of electrons with very high transverse momentum has been studied in the UA2 experiment at the CERN\(\bar pp\) collider (\(\sqrt s\)=540 GeV). From a sample of events containing an electron candidate withpT>15 GeV/c, we extract a clear signal resulting from the production of the charged intermediate vector bosonW±, which subsequently decays into an electron and a neutrino. We study theW production and decay properties. Further-more, we refine our results on the production and decay of the neutral vector bosonZ0. Finally, we compare the experimental results to the predictions of the standard model of the unified electro-weak theory.
No description provided.
We present measurements of the αα elastic scattering differential cross section at √ s = 126 GeV in the range 0.05 ⩽ ‖ t ‖
ERRORS ARE STATISTICAL ONLY.
EXPONENTIAL FIT TO CROSS SECTION BELOW T = 0.075 GEV**2.
OPTICAL THEOREM CALCULATION OF THE TOTAL CROSS SECTION ASSUMING RHO IS ZERO.
We report the observation of 21 dimuon events at the CERN p p Collider with the UA1 detector. The events range in invariant dimuon mass from 2 to 22 GeV / c 2 . The properties of these events are given. The bulk of the events are consistent with heavy-flavour production (mainly b b ) with a few candidates for Drell-Yan production. There remain a few events which are difficult to interpret in terms of these processes, in particular two events with isolated, like-sign muons.
No description provided.
No description provided.
Results are presented on two-jet and three-jet cross sections, measured in the UA1 experiment at the CERN Super Proton Synchrotron (SPS) pp̄ Collider, at the highest available subprocess cms energies ( s ̂ >150 GeV ). Precise measurements of the two-jet angular distribution are consistent with previous results but show significant scale-breaking effects. The three-jet Dalitz plot and the three-jet angular distributions show evidence for final- and initial-state bremsstrahlung processes, in agreement with the leading-order QCD predictions. A comparison of the yield of wide-angle three-jet events with the yield of two-jet events at smaller scattering angles gives for the strong interaction coupling constant: α s ( K 3J K 2J )=0.16±0.02±0.03 at Q 2 ≈4000 GeV 2 , where the factor K 3J K 2J may plausibly be assumed to be close to unity.
No description provided.
No description provided.
The production properties of a sample of 172 charged intermediate vector bosons produced at the CERN Super Proton Synchrotron Collider are described. The production cross-section, the longitudinal- and transverse-momentum distributions and the properties of hadronic jet activity produced in association with the weak bosons are in agreement with the expectations of the QCD-improved Drell-Yan mechanism.
No description provided.
The properties of a sample of 172 charged intermediate vector bosons decaying in the (eνe) channel and 16 neutral intermediate vector bosons decaying in the (e+e-) channel are described. Masses, decay widths, decay angular distributions, and production cross-sections are given; they are shown to be in excellent agreement with the expectations of the SU2 ⊗ U1 standard model. A limit is put on the number of light-neutrino types Nν ≤ 10 at 90% c.l.
W CROSS SECTIONS ARE GIVEN IN ARNISON ET AL., NC 44A, 1.
No description provided.
New data are presented on charged particle multiplicity distributions for non single-diffractive events produced at CM energies s = 200 and 900 GeV . The data were obtained at the CERN antiproton-proton collider operated in a new pulsed mode. The multiplicity distributions are very well described by a negative binomial distribution. The highest energy data show no sign of approaching scaling, confirming our earlier results on the breaking of KNO scaling. The energy variation of the average charged multiplicity can be fitted to a quadratic in ln s or a s 0.13 dependence.
Figure gives uncorrected multiplicity distributions. Here we give the corrected distributions. Data supplied by D. Ward.
Results for multiplicity moments based on negative binomial fit to corrected data. Errors reflect both statistical and systematic effects. Results from earlier data at 546 Gev cm energy are also given.
C moments for corrected data where CQ=<N**Q>/<N>**Q.
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