25 research outputs found
Diffractive Dijet Production at sqrt(s)=630 and 1800 GeV at the Fermilab Tevatron
We report a measurement of the diffractive structure function of
the antiproton obtained from a study of dijet events produced in association
with a leading antiproton in collisions at GeV at the
Fermilab Tevatron. The ratio of at GeV to
obtained from a similar measurement at GeV is compared with
expectations from QCD factorization and with theoretical predictions. We also
report a measurement of the (-Pomeron) and ( of parton in
Pomeron) dependence of at GeV. In the region
, GeV and , is
found to be of the form , which obeys
- factorization.Comment: LaTeX, 9 pages, Submitted to Phys. Rev. Letter
A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab
We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the
creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c
s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at
sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron
collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi
K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) =
(1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from
psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)
Search for Single-Top-Quark Production in p-pbar Collisions at sqrt(s)=1.8 TeV
We search for standard model single-top-quark production in the W-gluon
fusion and W* channels using 106 pb^-1 of data from p-pbar collisions at
sqrt(s)=1.8 TeV collected with the Collider Detector at Fermilab. We set an
upper limit at 95% C.L. on the combined W-gluon fusion and W* single-top cross
section of 14 pb, roughly six times larger than the standard model prediction.
Separate 95% C.L. upper limits in the W-gluon fusion and W* channels are also
determined and are found to be 13 and 18 pb, respectively.Comment: 6 pages, 2 figures; submitted to Phys. Rev. Let
Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV
We report a measurement of the ratio of the bottom quark production cross
section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom
quarks with transverse momenta greater than 10.75 GeV identified through their
semileptonic decays and long lifetimes. The measured ratio
sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with
next-to-leading order (NLO) quantum chromodynamics (QCD)
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Observation of Xi - production in e+e- annihilation at 29 GeV.
Inclusive - production in e+e- annihilation at 29 GeV has been measured with the Mark II detector. From an integrated luminosity of 207 pb-1, we determine a production rate of 0.0170.0040.004 -++ per hadronic event. A search for *0(1530)-+ leads to an upper limit of N(*0)/N(-)<0.35 at a 90% confidence level. © 1987 The American Physical Society
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Measurement of γγψ final states in ψ′ decay
The decay mode ψ′→γγψ has been studied with the Mark-II detector at SPEAR. New measurements of branching ratios for decays of the type ψ′→γχ, χ→γψ involving known χ states are presented. The existence of a χ state of mass near 3455 MeV/c2 produced in this decay chain is not confirmed, and the upper limit (90% confidence level) of the product of branching ratios is measured to be 0.13%. A new decay mode, ψ′→π0ψ, which violates isospin conservation is observed with branching ratio (0.15±0.06)%. © 1980 The American Physical Society
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Measurement of γγψ final states in ψ′ decay
The decay mode ψ′→γγψ has been studied with the Mark-II detector at SPEAR. New measurements of branching ratios for decays of the type ψ′→γχ, χ→γψ involving known χ states are presented. The existence of a χ state of mass near 3455 MeV/c2 produced in this decay chain is not confirmed, and the upper limit (90% confidence level) of the product of branching ratios is measured to be 0.13%. A new decay mode, ψ′→π0ψ, which violates isospin conservation is observed with branching ratio (0.15±0.06)%. © 1980 The American Physical Society
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Observation of the c (2980) Produced in the Radiative Decay of the (3684)
In a study of (3684) radiative decays with the Mark II detector at SPEAR, the decay sequence c (2980) is observed, with the c (2980) decaying into several completely reconstructed hadronic modes. A mass M=29808 MeV/c2 and a width <40 MeV/c2 (90%) confidence level) are obtained, and estimates of some of the decay branching ratios are presented. © 1980 The American Physical Society