Data are presented on the reactions K ± p → π 0 X, K ± p → η X, pp → π 0 X and p p → π 0 X in the kinematic region with s ⋍ 200 GeV 2 , x ≳ 0.7 and − t ≲ 1 GeV 2 . The data agree well with the predictions of triple-Regge theory and the K ∗ and nucleon Regge trajectories extracted from the data agree with the linear trajectories extrapolated from the particle poles.
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We have measured the ratio of inclusive production of η to π0 at transverse momenta above 1.5 GeV/c. Results are presented for various meson and proton beams with momenta of 100, 200, and 300 GeV/c incident upon a hydrogen target. The ηπ0 production ratio is found to be independent of incident beam momentum and of the transverse and longitudinal momenta of production. The ratio for pion- and proton-induced reactions is 0.44 ± 0.05; for kaons, it is 0.74 ± 0.12.
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We present data on π0 and η inclusive production from 100-GeV/c π±p collisions in the kinematic region x>~0.7 and 0<−t≲4 (GeV/c)2. The results are in excellent agreement with the predictions of triple-Regge theory and we have extracted the ρ and A2 trajectories out to −t=4 (GeV/c)2.
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We compare high-transverse-momentum (P⊥) inclusive π0 production from π−, K−, p, and p¯ beams, at 100 and 200 GeV/c, for center-of-mass (c.m.) angles ranging from 2° to 115° and P⊥<4.5 GeV/c. The ratio σ(pp→π0X)σ(πp→π0X) decreases with increasing P⊥, and changes dramatically with c.m. angle. Also, the ratios σ(K−p→π0X)σ(π−p→π0X) and σ(p¯p→π0X)σ(pp→π0X) are approximately constant. These measurements are consistent with a theoretical viewpoint in which constituents of the incident hadrons undergo a hard-scattering subprocess.
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We report the full reconstruction of χc mesons through the decay chain χc→J/ψ γ, J/ψ→μ+μ−, using data obtained at the Collider Detector at Fermilab in 2.6±0.2 pb−1 of p¯p collisions at √s =1.8 TeV. This exclusive χc sample is used to measure the χc-meson production cross section times branching fractions. We obtain σ×B=3.2±0.4(stat)−1.1+1.2(syst) nb for χc mesons decaying to J/ψ with pT>6.0 GeV/c and pseudorapidity ‖η‖<0.5. From this and the inclusive J/ψ cross section we calculate the inclusive b-quark cross section to be 12.0±4.5 μb for pTb>8.5 GeV/c and ‖yb‖<1.
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This determination of the b-quark cross section uses an earlier CDF measurement of the pbar p --> J/PSI X cross section of 6.88 +- 1.11 nb. See Abe et al. PRL 69, 3704.
We present a measurement of the b-quark cross section in 1.8 TeV p-p¯ collisions recorded with the Collider Detector at Fermilab using muonic b-quark decays. In the central rapidity region (‖yb‖<1.0), the cross section is 295±21±75 nb (59±14±15 nb) for pTb>21 GeV/c (29 GeV/c). Comparisons are made to previous measurements and next-to-leading order QCD calculations.
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We present measurements of the bottom-quark production cross sections in pp¯ collisions at √s =1.8 TeV. From the inclusive electron production rate, we have determined the bottom-quark production cross sections to be 1010±270, 168±43, 37±10 nb for the rapidity range of ‖yb‖<1.0 and the transverse momentum ranges of pTb>15, 23, 32 GeV/c, respectively. In addition, from the associated electron-D0 production rate, we have determined the bottom-quark cross section to be 364±80(stat)±95(syst) nb for ‖yb‖<1.0 and pTb>19 GeV/c.
From the inclusive electron production rate.
From the associated electron-D0 production rate.
Inclusive jet cross sections have been measured in p¯p collisions at √s =546 and 1800 GeV, using the Collider Detector at Fermilab. The ratio of jet cross sections is compared to predictions from simple scaling and O(as3) QCD. Our data exclude scaling and lie (1.5–2.4)σ below a range of QCD predictions.
Additional systematic uncertainty +23,-26 pct.
Additional systematic uncertainty +-16 pct.
Additional systematic uncertainty +-0.22.
We present measurements from events with two isolated prompt photons in p¯p collisions at √s =1.8 TeV. The differential cross section, measured as a function of transverse momentum (PT) of each photon, is about 3 times what next-to-leading-order QCD calculations predict. The cross section for photons with PT in the range 10–19 GeV is 86±27(stat)−23+32(syst) pb. We also study the correlation between the two photons in both azimuthal angle and PT. The magnitude of the vector sum of the transverse momenta of both photons, KT=‖PT1+PT2‖, has a mean value of 〈KT〉=5.1±1.1 GeV.
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Vector sum of the photons transvserse momenta.. Errors contain both statistics and systematics.. Data read from plots.
If quarks are composite particles then excited states are expected. We have searched in pp¯ collisions for excited quarks (q*) which decay to common quarks by emitting a W boson (q*→qW) or a photon (q*→qγ). The simplest model of excited quarks has been excluded for mass M*<540 GeV/c2 at 95% confidence level.
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