We present the first measurement of the jet pseudorapidity distribution in direct photon events from a sample of pp¯ collisions at s=1.8TeV, recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from hard quark-gluon Compton scattering, qg→qγ, with the final state quark producing the jet of hadrons. The jet pseudorapidity distribution in this model is sensitive to parton momentum fractions between 0.015 and 0.15. We find that the shape of the measured pseudorapidity distribution agrees well with next-to-leading order QCD calculations.Received 14 August 1997DOI:https://doi.org/10.1103/PhysRevD.57.1359©1998 American Physical Society

Pseudorapidity

10.1103/physrevd.57.1359

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Citations (3)

Measurement of the ratio σ(W→eν)/σ(Z→ee) inp¯pcollisions at√s =1.8TeV

Physical Review Letters (1990)

F. Abe D. Amidei G. Apollinari M. Ataç P. Auchincloss

An analysis of W- and Z-boson production using data from the Collider Detector at Fermilab at \ensuremath{\surd}s =1.8 TeV yields \ensuremath{\sigma}(W\ensuremath{\rightarrow}ev)/\ensuremath{\sigma}(Z\ensuremath{\rightarrow}ee)=10.2\ifmmode\pm\else\textpm\fi{}0.8(stat)\ifmmode\pm\else\textpm\fi{}0.4(syst). The width of the W boson, \ensuremath{\Gamma}(W), and a limit on the top-quark mass independent of decay mode are extracted from this measurement.

Fermilab

Electron–positron annihilation

10.1103/physrevlett.64.152

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Citations (30)

Dijet Production by Double Pomeron Exchange at the Fermilab Tevatron

Physical Review Letters (2000)

A. A. Affolder H. Akimoto A. Akopian M. G. Albrow P. Amaral

We report the first observation of dijet events with a double Pomeron exchange topology produced in &pmacr;p collisions at sqrt[s] = 1800 GeV. The events are characterized by a leading antiproton, two jets in the central pseudorapidity region, and a large rapidity gap on the outgoing proton side. We present results on jet kinematics and production rates, compare them with corresponding results from single diffractive and inclusive dijet production, and test factorization.

Pseudorapidity

Pomeron

Fermilab

Antiproton

10.1103/physrevlett.85.4215

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Citations (55)

Search for a Fourth-Generation Quark More Massive than theZ0Boson inpp<…

Physical Review Letters (2000)

T. Affolder H. Akimoto A. Akopian M. Albrow P. Amaral

We present the results of a search for pair production of a fourth-generation charge $\ensuremath{-}\frac{1}{3}$ quark $({b}^{\ensuremath{'}})$ in $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ $p\overline{p}$ collisions using $88{\mathrm{pb}}^{\ensuremath{-}1}$ of data obtained with the Collider Detector at Fermilab. We assume that both quarks decay via the flavor-changing neutral current process ${b}^{\ensuremath{'}}\ensuremath{\rightarrow}{\mathrm{bZ}}^{0}$ and that the ${b}^{\ensuremath{'}}$ mass is greater than ${m}_{Z}{+m}_{b}$. We studied the decay mode ${b}^{\ensuremath{'}}\overline{{b}^{\ensuremath{'}}}\ensuremath{\rightarrow}{Z}^{0}{Z}^{0}b\overline{b}$ where one ${Z}^{0}$ decays into ${e}^{+}{e}^{\ensuremath{-}}$ or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and the other decays hadronically, giving a signature of two leptons plus jets. An upper limit on the ${\ensuremath{\sigma}}_{p\overline{p}\ensuremath{\rightarrow}{b}^{\ensuremath{'}}\overline{{b}^{\ensuremath{'}}}}\ifmmode\times\else\texttimes\fi{}[B({b}^{\ensuremath{'}}\ensuremath{\rightarrow}{\mathrm{bZ}}^{0}){]}^{2}$ is established as a function of the ${b}^{\ensuremath{'}}$ mass. We exclude at $95%$ confidence level a ${b}^{\ensuremath{'}}$ quark with mass between 100 and $199\mathrm{GeV}{/c}^{2}$ for $B({b}^{\ensuremath{'}}\ensuremath{\rightarrow}{\mathrm{bZ}}^{0})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}100%$.

10.1103/physrevlett.84.835

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Citations (27)

Leptonic decays of the $Sigma$$sup -$ and $Xi$$sup -$ hyperons

Physical Review D (1975)

W. Tanenbaum V. Hungerbühler R. Majka J. N. Marx P. Némethy

The decays $Sigma$$sup -$$Yields$ne$sup -$anti $nu$, $Sigma$$sup - $$Yields$$lambda$e$sup -$anti $nu$ ($lambda$$Yields$$pi$$sup -$p), and $Xi$$sup - $$Yields$$lambda$e$sup -$anti $nu$ ($lambda$$Yields$$pi$$sup -$p) were studied using unpolarized hyperons from the Yale--Fermilab--BNL hyperon beam at the Brookhaven National Laboratory Alernating Gradient Synchrotron. The $Sigma$$sup - $, $Xi$$sup -$, e$sup -$, and $lambda$-decay-product momenta were measured by magnetic spectrometers with magnetostrictive wire spark chambers. A threshold Cherenkov counter and a total absorption calorimeter identified the electron and neutron, respectively. From a sample of 3507 reconstructed $Sigma$$sup - $$Yields$ne$sup -$anti $nu$ events we have found the abs. value of g/sub A//g/sub V/ = 0.435+-0.035. From a sample of 55 reconstructed $Sigma$$sup - $$Yields$$lambda$e$sup -$anti $nu$ events we have found g/sub V//g/sub A/ = 0.17+- 0.35, assuming that the conserved vector current hypothesis correctly predicts the weak magnetic form factor. A new one-angle Cabibbo fit gives f = 0.436+- 0.010, d = 0.812+-0.011, and theta + 0.232+-0.003 radian. (AIP)

Lambda baryon

Source

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Search for Scalar Top and Scalar Bottom Quarks inpp¯Collisions ats

Physical Review Letters (2000)

A. A. Affolder H. Akimoto A. Akopian M. G. Albrow P. Amaral

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

Pair production

10.1103/physrevlett.84.5704

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Citations (52)

Search forΞ*−,Σ*−, and Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields (1974)

V. Hungerbühler R. Majka J. N. Marx P. Némethy J. Sandweiss

The reactions of 24.6-GeV/c ${\ensuremath{\Sigma}}^{\ensuremath{-}}$ and ${\ensuremath{\Xi}}^{\ensuremath{-}}$ incident on a scintillator target were studied in a counter-spark chamber experiment. Upper limits on the production cross sections of ${\ensuremath{\Sigma}}^{*\ensuremath{-}}$ resonances which decay into ${\ensuremath{\Lambda}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\Xi}}^{*\ensuremath{-}}$ resonances which decay into ${\ensuremath{\Lambda}}^{0}{K}^{\ensuremath{-}}$ were obtained. A single ${\ensuremath{\Omega}}^{\ensuremath{-}}$ that was produced in the scintillator target has been observed, corresponding to a 115-\ensuremath{\mu}b/nucleon production cross section if produced by a ${\ensuremath{\Xi}}^{\ensuremath{-}}$. The ${\ensuremath{\Lambda}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ mass spectrum was found to be consistent with a Deck-type threshold enhancement.

10.1103/physrevd.10.2051

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Citations (6)

Search for a light Higgs boson at the Fermilab Tevatron proton-antiproton collider

Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields (1990)

F. Abe D. Amidei G. Apollinari M. Ataç P. Auchincloss

We have searched for a light standard-model Higgs boson produced in association with an intermediate vector boson at the Fermilab proton-antiproton collider operating at a center-of-mass energy of 1.8 TeV. The search was made by looking for an excess of isolated high-transverse-momentum charged-track pairs in $W$ and $Z$ events. A Higgs boson with a mass ${m}_{H}$ in the intervals $2{m}_{\ensuremath{\mu}}<{m}_{H}<818$ MeV/${\mathit{c}}^{2}$, and $846 \frac{\mathrm{MeV}}{{c}^{2}}<{m}_{H}<2{m}_{K}$ is excluded at 90% C.L.

Fermilab

Antiproton

10.1103/physrevd.41.1717

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Citations (3)

Inclusiveπ0production by high-energy protons

Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields (1976)

David C. Carey J. R. Johnson R. Kammerud David J. Ritchie A. Roberts

Measurements of the cross section for the reaction $p+p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}+\mathrm{anything}$ have been completed. The data cover a range of incident proton energies 50-400 GeV, ${\ensuremath{\pi}}^{0}$ transverse momenta 0.3-4 GeV/c, and laboratory angles 30-275 mrad. The experiment was performed using the internal proton beam at the Fermi National Accelerator Laboratory. A lead-glass counter was used to detect photons from the decay of ${\ensuremath{\pi}}^{0}'\mathrm{s}$ produced by collisions in thin targets of hydrogen or carbon. Tables of the measured cross sections are presented.

10.1103/physrevd.14.1196

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Citations (18)

Measurement ofbb¯rapidity correlations inpp¯

Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields (1999)

F. Abe H. Akimoto A. Akopian M. Albrow A. Amadon

We report the first direct measurement of bb¯ rapidity correlations in pp¯ collisions at s=1.8TeV. We select events with a high transverse momentum muon accompanied by a jet, and a second jet associated with a decay vertex displaced from the pp¯ interaction vertex. Two independent samples are obtained corresponding to events with a forward (2.0<|η|<2.6) or central (|η|<0.6) muon. We measure the ratio of forward to central bb¯ production to be 0.361±0.033(stat)−0.031+0.015(syst), in good agreement with the next-to-leading order QCD prediction 0.338−0.097+0.014. Received 7 December 1998DOI:https://doi.org/10.1103/PhysRevD.61.032001©1999 American Physical Society

10.1103/physrevd.61.032001

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Citations (28)