Amidei, Dante E
[1000.0, 7000.0]
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Probing hard color singlet exchange in p anti-p collisions at S**(1/2) = 630-GeV and 1800-GeV

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Lett.B 440 (1998) 189-202, 1998.
Inspire Record 476389 DOI 10.17182/hepdata.42131

We present results on dijet production via hard color-singlet exchange in proton-antiproton collisions at root-s = 630 GeV and 1800 GeV using the DZero detector. The fraction of dijet events produced via color-singlet exchange is measured as a function of jet transverse energy, separation in pseudorapidity between the two highest transverse energy jets, and proton-antiproton center-of-mass energy. The results are consistent with a color-singlet fraction that increases with an increasing fraction of quark-initiated processes and inconsistent with two-gluon models for the hard color-singlet.

2 data tables
Table 1

Colour-singlet fraction at 1.8 TeV.

Table 2

Ratio of colour-singlet fractions between 630 and 1800 GeV.


Search for Higgs bosons produced in association with a vector boson in p anti-p collisions at S**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 81 (1998) 5748-5753, 1998.
Inspire Record 475077 DOI 10.17182/hepdata.42136

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

1 data table
Table 1

Cross section from the hadronic analysis fit (C=MEASURED) plus 95 PCT confidence upper limits from the hadronic, leptonic and combined analyses.


The Inclusive jet cross-section in anti-p p collisions at S**(1/2) = 1.8-TeV

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Rev.Lett. 82 (1999) 2451-2456, 1999.
Inspire Record 473457 DOI 10.17182/hepdata.42154

We have made a precise measurement of the central inclusive jet cross section at sqrt(s) = 1.8 TeV. The measurement is based on an integrated luminosity of 92 pb-1 collected at the Fermilab Tevatron pbar-p Collider with the D-Zero detector. The cross section, reported as a function of jet transverse energy (ET >= 60 GeV) in the pseudorapidity interval |eta| <= 0.5, is in good agreement with predictions from next-to-leading order quantum chromodynamics.

2 data tables
Table 1

Inclusive cross section for ABS(ETARAP)<0.5. The quoted systematic (DSYS) errors do not include the luminosity uncertainty of 6.1 PCT.

Table 2

Inclusive cross section for 0.1<=ABS(ETARAP)<=0.7. Data are taken from the AIP E-PAPS ftp site shown above. The quoted (DSYS) errors are the total systematic errors including the luminosity uncertainty.


Search for second generation leptoquarks in the dimuon plus dijet channel of p anti-p collisions at S**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 81 (1998) 4806-4811, 1998.
Inspire Record 473168 DOI 10.17182/hepdata.42155

We report on a search for second generation leptoquarks (Phi_2) using a data sample corresponding to an integrated luminosity of 110 pb^{-1} collected at the Collider Detector at Fermilab. We present upper limits on the production cross section as a function of Phi_2 mass, assuming that the leptoquarks are produced in pairs and decay into a muon and a quark with branching ratio beta. Using a Next-to-Leading order QCD calculation, we extract a lower mass limit of M_{\Phi_2} > 202 (160) GeV$/c^{2} at 95% confidence level for scalar leptoquarks with beta=1(0.5).

1 data table
Table 1

Cross section times branching ratios.


The Dijet mass spectrum and a search for quark compositeness in anti-p p collisions at S**(1/2) = 1.8-TeV

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Rev.Lett. 82 (1999) 2457-2462, 1999.
Inspire Record 473420 DOI 10.17182/hepdata.42143

Using the DZero detector at the 1.8 TeV pbarp Fermilab Tevatron collider, we have measured the inclusive dijet mass spectrum in the central pseudorapidity region |eta_jet| < 1.0 for dijet masses greater than 200 Gev/c^2. We have also measured the ratio of spectra sigma(|eta_jet| < 0.5)/sigma(0.5 < |eta_jet| < 1.0). The order alpha_s^3 QCD predictions are in good agreement with the data and we rule out models of quark compositeness with a contact interaction scale < 2.4 TeV at the 95% confidence level.

2 data tables
Table 1

Dijet cross section for ABS(ETARAP)<1.0.

Table 2

Ratio of cross sections for ABS(ETARAP) < 0.5 / 0.5 < ABS(ETARAP) < 1.0.


Small angle J / psi production in p anti-p collisions at S**(1/2) = 1.8-TeV

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Rev.Lett. 82 (1999) 35-40, 1999.
Inspire Record 473954 DOI 10.17182/hepdata.42141

This paper presents the first measurement of the inclusive J/Psi production cross section in the forward pseudorapidity region 2.5<|eta|<3.7 in ppbar collisions at sqrt(s)=1.8TeV. The results are based on 9.8 pb-1 of data collected using the D0 detector at the Fermilab Tevatron Collider. The inclusive J/Psi cross section for transverse momenta between 1 and 16 GeV/c is compared with theoretical models of charmonium production.

1 data table
Table 1

Only statistical errors are shown. Cross section tines branching ratio.


Dijet production in photon-photon collisions at S**(1/2)(ee) = 161-GeV and 172-GeV

The OPAL collaboration Abbiendi, G. ; Ackerstaff, K. ; Alexander, G. ; et al.
Eur.Phys.J.C 10 (1999) 547-561, 1999.
Inspire Record 474009 DOI 10.17182/hepdata.49386

Di-jet production is studied in collisions of quasi-real photons radiated by the LEP beams at e+e- centre-of-mass energies 161 and 172 GeV. The jets are reconstructed using a cone jet finding algorithm. The angular distributions of direct and double-resolved processes are measured and compared to the predictions of leading order and next-to-leading order perturbative QCD. The jet energy profiles are also studied. The inclusive two-jet cross-section is measured as a function of transverse energy and rapidity and compared to next-to-leading order perturbative QCD calculations. The inclusive two-jet cross-section as a function of rapidity is compared to the prediction of the leading order Monte Carlo generators PYTHIA and PHOJET. The Monte Carlo predictions are calculated with different parametrisations of the parton distributions of the photon. The influence of the `underlying event' has been studied to reduce the model dependence of the predicted jet cross-sections from the Monte Carlo generators.

14 data tables
Table 1

Differential 2-jet cross section as a function of cos(theta*) for 'double-resolved' and 'direct' events.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of the sigma(W + >= 1 jet) / sigma(W) cross-section ratio from anti-p p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 81 (1998) 1367-1372, 1998.
Inspire Record 469969 DOI 10.17182/hepdata.42146

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.

1 data table
Table 1

No description provided.


A search for heavy pointlike Dirac monopoles

The D0 collaboration Abbott, B. ; Abolins, M. ; Acharya, Bannanje Sripath ; et al.
Phys.Rev.Lett. 81 (1998) 524-529, 1998.
Inspire Record 468445 DOI 10.17182/hepdata.42158

We have searched for central production of a pair of photons with high transverse energies in $p\bar p$ collisions at $\sqrt{s} = 1.8$ TeV using $70 pb^{-1}$ of data collected with the D\O detector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of $610, 870, or 1580 GeV/c^2$ on the mass of a spin 0, 1/2, or 1 Dirac monopole.

1 data table
Table 1

No description provided.


Search for the rare decay W+- ---> pi+- + gamma in proton - anti-proton collisions at S**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.D 58 (1998) 031101, 1998.
Inspire Record 468516 DOI 10.17182/hepdata.42167

We have searched for the rare decay W±→π±+γ in 83 pb−1 of data taken in proton-antiproton collisions at s=1.8 TeV with the Collider Detector at Fermilab. We find three events in the signal region and estimate the background to be 5.2±1.5 events. We set a 95% confidence level upper limit of 7×10−4 on the ratio of partial widths, Γ(W±→π±+γ)/Γ(W±→e±+ν).

1 data table
Table 1

No description provided.