236 research outputs found
Search for charged Higgs decays of the top quark using hadronic tau decays
We present the result of a search for charged Higgs decays of the top quark,
produced in collisions at 1.8 TeV. When the charged
Higgs is heavy and decays to a tau lepton, which subsequently decays
hadronically, the resulting events have a unique signature: large missing
transverse energy and the low-charged-multiplicity tau. Data collected in the
period 1992-1993 at the Collider Detector at Fermilab, corresponding to
18.70.7~pb, exclude new regions of combined top quark and charged
Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp;
submitted to Phys. Rev.
Inclusive jet cross section in collisions at TeV
The inclusive jet differential cross section has been measured for jet
transverse energies, , from 15 to 440 GeV, in the pseudorapidity region
0.10.7. The results are based on 19.5 pb of data
collected by the CDF collaboration at the Fermilab Tevatron collider. The data
are compared with QCD predictions for various sets of parton distribution
functions. The cross section for jets with GeV is significantly
higher than current predictions based on O() perturbative QCD
calculations. Various possible explanations for the high- excess are
discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review
Letter
Search for New Particles Decaying to Dijets at CDF
We have used 106 pb^-1 of data collected with the Collider Detector at
Fermilab to search for new particles decaying to dijets. We exclude at the 95%
confidence level models containing the following new particles: axigluons and
flavor universal colorons with mass between 200 and 980 GeV/c, excited quarks
with mass between 80 and 570 GeV/c^2 and between 580 and 760 GeV/c^2, color
octet technirhos with mass between 260 and 480 GeV/c^2, W' bosons with mass
between 300 and 420 GeV/c^2, and E_6 diquarks with mass between 290 and 420
GeV/c^2.Comment: 18 pages, 4 figures, 1 table. Submitted to Physical Review D Rapid
Communications. Postscript file of paper is also available at
http://www-cdf.fnal.gov/physics/pub97/cdf3276_dijet_search_prd_rc.p
Measurement of Dijet Angular Distributions at CDF
We have used 106 pb^-1 of data collected in proton-antiproton collisions at
sqrt(s)=1.8 TeV by the Collider Detector at Fermilab to measure jet angular
distributions in events with two jets in the final state. The angular
distributions agree with next to leading order (NLO) predictions of Quantum
Chromodynamics (QCD) in all dijet invariant mass regions. The data exclude at
95% confidence level (CL) a model of quark substructure in which only up and
down quarks are composite and the contact interaction scale is Lambda_ud(+) <
1.6 TeV or Lambda_ud(-) < 1.4 TeV. For a model in which all quarks are
composite the excluded regions are Lambda(+) < 1.8 TeV and Lambda(-) < 1. 6
TeV.Comment: 16 pages, 2 figures, 2 tables, LaTex, using epsf.sty. Submitted to
Physical Review Letters on September 17, 1996. Postscript file of full paper
available at http://www-cdf.fnal.gov/physics/pub96/cdf3773_dijet_angle_prl.p
The Charge Asymmetry in W-Boson Decays Produced in p-pbar Collisions at sqrt(s) = 1.8 TeV
The charge asymmetry has been measured using decays recorded by
the CDF detector during the 1992-93 run of the Tevatron Collider. The asymmetry
is sensitive to the ratio of and quark distributions to at
, where nonperturbative effects are minimal. It is found
that of the two current sets of parton distributions, those of Martin, Roberts
and Stirling (MRS) are favored over the sets most recently produced by the CTEQ
collaboration. The asymmetry data provide a stronger constraints on
ratio than the recent measurements of which are
limited by uncertainties originating from deutron corrections.Comment: to be published in PR
Search for New Particles Decaying to Dijets in p-pbar Collisions at sqrt(s)=1.8 TeV
We have used 19 pb**-1 of data collected with the Collider Detector at
Fermilab to search for new particles decaying to dijets. We exclude at 95%
confidence level models containing the following new particles: axigluons with
mass between 200 and 870 GeV, excited quarks with mass between 80 and 570 GeV,
and color octet technirhos with mass between 320 and 480 GeV.Comment: Submitted to Physical Review Letters in December 199
Measurement of and in collisions at TeV
We present a measurement of and in proton - antiproton collisions at TeV
using a significantly improved understanding of the integrated luminosity. The
data represent an integrated luminosity of 19.7 pb from the 1992-1993
run with the Collider Detector at Fermilab (CDF). We find ~nb and ~nb.Comment: Uses Latex, Article 12 point, figure appended as uuencoded file The
full PostScript available via WWW at
http://www-cdf.fnal.gov/physics/pub95/cdf3312_sigma_1a_prl_v3.p
Search For Charged Higgs Decays of the Top Quark Using Hadronic Decays of the Tau Lepton
This Letter describes a direct search for charged Higgs boson production in
proton-antiproton collisions at sqrt(s)=1.8 TeV recorded by the Collider
Detector at Fermilab. Two-Higgs-doublet extensions to the standard model
predict the existence of charged Higgs bosons. In such models, the branching
fraction for top quarks B(t --> H b --> tau nu b) can be large. This search
uses the hadronic decays of the tau lepton in this channel to significantly
extend previous limits on charged Higgs production.Comment: 6pages, 4 figures, 1 table; LaTeX; submitted to PR
Ratios of bottom meson branching fractions involving J/psi mesons and determination of b quark fragmentation fractions
We report a measurement of the ratios of the decay rates of the B^+, B^0 and
B^0_s mesons into exclusive final states containing a J/psi meson. The final
states were selected from 19.6 pb^{-1} of p-pbar collisions recorded by the
Collider Detector at Fermilab. These data are interpreted to determine the
bquark fragmentation fractions f_u, f_d and f_s. We also determine the
branching fractions for the decay modes B^+ --> J/psi K^+, B^+ --> J/psi
K^*(892)^+, B^0 --> J/psi K^0, B^0 --> J/psi K^*(892)^0 and B_s^0 --> J/psi
phi(1020). We discuss the implications of these measurements to B meson decay
models.Comment: 40 pages with 5 figures. Submitted to Phys. Rev. D. PostScript also
available at http://www-cdf.fnal.gov/physics/pub96/cdf3609_bfrag_br_prd.p
Limits on and couplings from and production in collisions at TeV
Direct limits are set on and three-boson couplings in a
search for and production with high transverse momentum in
collisions at TeV, using the Collider Detector
at Fermilab. The results are in agreement with the SU(2) U(1) model of
electroweak interactions. Assuming Standard Model coupling, the the
limits are interpreted as direct evidence for a non-zero coupling at
subprocess energies near 500 GeV. Alternatively, assumiong identical and
couplings, bounds and are obtained at CL for a form factor scale 1000 GeV.Comment: 16 pages, submitted to PRL, URL:
http://www-cdf.fnal.gov/physics/pub95/cdf2951_vvprl.p
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