We have measured the differential cross section for pp and p̄p elastic scattering at √ s = 31, 53 and 62 GeV in the interval 0.05 < | t | < 0.85 GeV 2 at the CERN ISR using the Split Field Magnet detector. At 53 and 62 GeV, for 0.17 < | t | < 0.85 GeV 2 both pp and p̄p data show simple exponential behaviour in t ; at √ s = 31 GeV the data for 0.05 < | t | < 0.85 GeV 2 are consistent with a change in slope near | t | = 0.15 GeV 2 .
ERRORS CONTAIN BOTH STATISTICAL AND T-DEPENDENT SYSYEMATIC ERRORS.
No description provided.
LOCAL SLOPE PARAMETERS BASED ON QUADRATIC EXPONENTIAL FIT.
The ratio R of the total cross section for e+e− annihilation into hadrons to the lowest-order QED cross section for e+e−→μ+μ− has been measured for center-of-mass energies ranging from 50 to 61.4 GeV. If we allow for an overall shift of —4.9%, about 1.5 times our estimated normalization error, the results are consistent with the standard-model predictions.
Error quoted contains point-to-point systematics. There is also an additional 3.2 pct systematic error.
The inclusive cross section for the production of charmed D<sup loc="post">∗±</sup> mesons in two-photon processes is measured with the AMY detector at the TRISTAN e<sup loc="post">+</sup>e<sup loc="post">−</sup> collider. D<sup loc="post">∗±</sup> mesons are identified from the distribution of charged-particle transverse momenta relative to the jet axis. A data sample corresponding to an integrated luminosity of 176 pb<sup loc="post">−1</sup> at a center-of-mass energy of 58 GeV is used to determine a cross section σ(e<sup loc="post">+</sup>e<sup loc="post">−</sup> → e<sup loc="post">+</sup>e<sup loc="post">−</sup>D<sup loc="post">∗±</sup>X) = 270 ± 49(stat) ± 38(syst) pb. The results are compared with theoretical expectations based on the Vector Meson Dominance, direct quark-parton model, and resolved photon processes.
No description provided.
Reduced acceptance region to compare with the TOPAZ results.
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No description provided.
Measurements of open charm production in photon-photon collisions made with the AMY detector at TRISTAN are reported. Charmed hadrons were identified by detecting the high momentum muons or electrons from their semileptonic decays. The data sample corresponds to an integrated luminosity of 275 pb −1 at an average center of mass energy of 58 GeV. Results are presented in the form of cross sections of inclusive leptons from charm for both muons and electrons. The measured cross section is 1.8 standard deviations higher than theoretical predictions based on the direct and photon-gluon fusion process, where the mass of charm quark is assumed to be 1.6 GeV.
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The multiplicities of charged secondaries in proton-proton collisions were determined using the split-field-magnet detector at the CERN Intersecting Storage Rings (ISR). Measurements are presented on multiplicity distributions both for inelastic and non-single-diffractive events at four different energies s=30.4, 44.5, 52.6, and 62.2 GeV. The results reported here represent the first high-statistics measurement of charged multiplicity distributions at ISR energies with a magnetic detector covering nearly the full solid angle.
INELASTIC EVENTS.
NON-SINGLE-DIFFRACTIVE EVENTS.
Moments of the multiplicity distributions for Inelastic events.
Single photon production in pp collisions at 30 < √ s < 62 GeV has been measured with liquid-argon-lead calorimeters at the CERN ISR. This process remains approximately constant with increasing √ s . For fixed √ s , the single photon to π 0 ratio increases strongly with increase in p T . The γ π 0 ratio is about 0.2 for p T above 4.5 GeV/c.
No description provided.
Differential and total cross-sections for photoproduction of gamma proton to proton pi0 omega and gamma proton to Delta+ omega were determined from measurements of the CB-ELSA experiment, performed at the electron accelerator ELSA in Bonn. The measurements covered the photon energy range from the production threshold up to 3GeV.
Differential cross section as a function of the OMEGA angle.
Differential cross section as a function of the OMEGA angle.
Differential cross section as a function of the PI0 angle.
We search for Higgs bosons produced in association with a massive vector boson in 91±7pb−1 of pp¯ collisions at s=1.8TeV recorded by the Collider Detector at Fermilab. We assume the Higgs scalar H0 decays to a bb¯ pair with branching ratio β, and we consider the hadronic decays of the vector boson V ( W or Z). Observations are consistent with background expectations. We place 95% confidence level upper limits on σ(pp¯→H0V)β as a function of the scalar mass (MH0) over the range 70<MH0<140GeV/c2. When combined with an analysis of the case where V is a leptonically decaying W, these limits vary from 23 pb at MH0=70GeV/c2 to 17 pb at MH0=140GeV/c2.
Cross section from the hadronic analysis fit (C=MEASURED) plus 95 PCT confidence upper limits from the hadronic, leptonic and combined analyses.
The ratio of the W+≥1 jet cross section to the inclusive W cross section is measured using W±→e±ν events from p¯p collisions at s=1.8TeV. The data are from 108pb−1 of integrated luminosity collected with the Collider Detector at Fermilab. Measurements of the cross section ratio for jet transverse energy thresholds (ETmin) ranging from 15 to 95 GeV are compared to theoretical predictions using next-to-leading-order QCD calculations. Data and theory agree well for ETmin>25GeV, where the predictions lie within 1 standard deviation of the measured values.
No description provided.
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