The elastic photoproduction cross sections for ρ and ϕ mesons from protons have been measured from 30 to 180 GeV. The energy dependences agree well with predictions made by using vector-meson dominance and an additive quark model. The ρ cross section is approximately constant with energy while the ϕ cross section rises from 0.5 to 0.7 μb with increasing energy.
The photon total cross section on protons has been measured with high precision in the Fermilab tagged-photon beam for photon energies from 18 to 185 GeV. The cross section decreases to a broad minimum near 40 GeV, and then rises by about 4 μb over the remainder of the range. A ρ+ω+ϕ vector-dominance model (normalized to low-energy data) falls below the high-energy results by 2 to 6 μb, suggesting a contribution from charm-anticharm states.
The energy dependence of the cross section for neutrino- and antineutrino-nucleon charged-current interactions has been determined from data taken in Fermilab's dichromatic neutrino beam. σνE=(0.669±0.003±0.024)×10−38 cm2/GeV and σν¯E=(0.340±0.003±0.02)×10−38 cm2/GeV are found. These results are higher than some previous measurements.
New measurements are reported of total cross sections for π ± , K ± , p and p on protons and deuterons at 11 momenta between 23 and 280 GeV/ c .
Measurements of flux-normalized neutrino and antineutrino total charged-current cross sections (σ) in the energy range 45<E<205 GeV are presented. We see no evidence for the anomalous sharp rise in σν¯σν reported by earlier authors. The neutrino cross section rises linearly with energy and with σE about 18% smaller than other measurements below 10 GeV. The average antineutrino slope at 55 GeV is consistent with measurements at low energy; however, a (20 ± 10)% increase is indicated over our energy range.
Total cross sections of π± and K± on protons and deuterons have been measured at 50, 100, 150, and 200 GeV/c. All of the cross sections rise with increasing momentum.
Proton and antiproton total cross sections on protons and deuterons have been measured at 50, 100, 150, and 200 GeV/c. The proton cross sections rise with increasing momentum. Antiproton cross sections fall with increasing momentum, but the rate of fall decreases between 50 and 150 GeV/c, and from 150 to 200 GeV/c there is little change in cross section.
We present the results of a search for third generation leptoquark (LQ) pairs in 110±8pb−1of p¯p collisions at s=1.8TeV recorded by the Collider Detector at Fermilab. We assume third generation leptoquarks decay to a τ lepton and a b quark with branching ratio β. We observe one candidate event, consistent with standard model background expectations. We place upper limits on σ(p¯p→LQLQ¯)̇β2 as a function of the leptoquark mass MLQ. We exclude at 95% confidence level scalar leptoquarks with MLQ<99GeV/c2, gauge vector leptoquarks with MLQ<225GeV/c2, and nongauge vector leptoquarks with MLQ<170GeV/c2 for β=1.
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.
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.
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