Measurement of the angular distribution of electrons from W ---> e neutrino decays observed 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.D 63 (2001) 072001, 2001.
Inspire Record 533572 DOI 10.17182/hepdata.41717

We present the first measurement of the electron angular distribution parameter alpha_2 in W to e nu events produced in proton-antiproton collisions as a function of the W boson transverse momentum. Our analysis is based on data collected using the D0 detector during the 1994--1995 Fermilab Tevatron run. We compare our results with next-to-leading order perturbative QCD, which predicts an angular distribution of (1 +/- alpha_1 cos theta* + alpha_2 cos^2 theta*), where theta* is the polar angle of the electron in the Collins-Soper frame. In the presence of QCD corrections, the parameters alpha_1 and alpha_2 become functions of p_T^W, the W boson transverse momentum. This measurement provides a test of next-to-leading order QCD corrections which are a non-negligible contribution to the W boson mass measurement.

0 data tables match query

Search for electroweak production of single top quarks in p anti-p collisions

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Rev.D 63 (2000) 031101, 2000.
Inspire Record 531764 DOI 10.17182/hepdata.42976

We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb.

0 data tables match query

High p(T) jets in anti-p p collisions at s**(1/2) = 630-GeV and 1800-GeV

The D0 collaboration Abbott, B. ; Abdesselam, A. ; Abolins, M. ; et al.
Phys.Rev.D 64 (2001) 032003, 2001.
Inspire Record 539003 DOI 10.17182/hepdata.42946

Results are presented from analyses of jet data produced in pbarp collisions at sqrt{s} = 630 and 1800 GeV collected with the DO detector during the 1994-95 Fermilab Tevatron Collider run. We discuss details of detector calibration, and jet selection criteria in measurements of various jet production cross sections at sqrt{s} = 630 and 1800 GeV. The inclusive jet cross sections, the dijet mass spectrum, the dijet angular distributions, and the ratio of inclusive jet cross sections at sqrt{s} = 630 and 1800 GeV are compared to next-to-leading-order QCD predictions. The order alpha_s^3 calculations are in good agreement with the data. We also use the data at sqrt{s} = 1800 GeV to rule out models of quark compositeness with a contact interaction scale less than 2.2 TeV at the 95% confidence level.

0 data tables match query

Search for first-generation scalar and vector leptoquarks

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abdesselam, A. ; et al.
Phys.Rev.D 64 (2001) 092004, 2001.
Inspire Record 557085 DOI 10.17182/hepdata.42922

We describe a search for the pair production of first-generation scalar and vector leptoquarks in the eejj and enujj channels by the D0 Collaboration. The data are from the 1992--1996 ppbar run at sqrt{s} = 1.8 TeV at the Fermilab Tevatron collider. We find no evidence for leptoquark production; in addition, no kinematically interesting events are observed using relaxed selection criteria. The results from the eejj and enujj channels are combined with those from a previous D0 analysis of the nunujj channel to obtain 95% confidence level (C.L.) upper limits on the leptoquark pair-production cross section as a function of mass and of beta, the branching fraction to a charged lepton. These limits are compared to next-to-leading-order theory to set 95% C.L. lower limits on the mass of a first-generation scalar leptoquark of 225, 204, and 79 GeV/c^2 for beta=1, 1/2, and 0, respectively. For vector leptoquarks with gauge (Yang-Mills) couplings, 95% C.L. lower limits of 345, 337, and 206 GeV/c^2 are set on the mass for beta=1, 1/2, and 0, respectively. Mass limits for vector leptoquarks are also set for anomalous vector couplings.

0 data tables match query

The Isolated photon cross-section 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. 84 (2000) 2786-2791, 2000.
Inspire Record 511200 DOI 10.17182/hepdata.42075

We report a new measurement of the cross section for the production of isolated photons, with transverse energies (ET) above 10 GeV and pseudorapidities |eta| < 2.5, in p pbar collisions at sqrt{s} = 1.8 TeV. The results are based on a data sample of 107.6 pb-1 recorded during 1992--1995 with the D0 detector at the Fermilab Tevatron collider. The background, predominantly from jets which fragment to neutral mesons, was estimated using the longitudinal shower shape of photon candidates in the calorimeter. The measured cross section is in good agreement with the next-to-leading order (NLO) QCD calculation for ET > 36 GeV.

0 data tables match query

Mass identified particle production in proton anti-proton collisions at s**(1/2) = 300-GeV, 540-GeV, 1000-GeV, and 1800-GeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Phys.Rev.D 48 (1993) 984-997, 1993.
Inspire Record 363171 DOI 10.17182/hepdata.22669

The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.

0 data tables match query

phi meson production from p anti-p collisions at s**(1/2) = 1.8-TeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Z.Phys.C 67 (1995) 411-416, 1995.
Inspire Record 405368 DOI 10.17182/hepdata.14115

Fermilab experiment E735 located at the CO intersection region of the\(\sqrt s= 1.8\) TeV\(p\bar p\) collider analysed over 900 Φ→K+K− events. Measured were the transverse momentum spectrum, the correlation between the average transverse momentum <pt> and the charged particle multiphcityNc, as well as the probability of Φ production per charged track,NΦ/Nc, versusNc. We have also made an estinate of the total inclusive cross section for Φ mesons,\(\sigma (p\bar p \to \phi X) = 7.3 \pm 2.2 mb\).

0 data tables match query

Cross-sections for deuterium, tritium, and helium production in p p collisions at s = 1.8-TeV

Alexopoulos, T. ; Anderson, E.W. ; Biswas, N.N. ; et al.
Phys.Rev.D 62 (2000) 072004, 2000.
Inspire Record 536253 DOI 10.17182/hepdata.22220

We present the results of a search for the production of light elements in p¯p collisions at the Fermilab Tevatron collider. Momentum, time of flight, and dE/dx measurements are used to distinguish nuclei from elementary particles. A production ratio for deuterium to hydrogen is calculated and compared to the primordial value of the big bang model. Some evidence for tritium is found and none for helium isotopes.

0 data tables match query

Observation of the top quark

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 74 (1995) 2632-2637, 1995.
Inspire Record 393099 DOI 10.17182/hepdata.42452

The DO collaboration reports on a search for the Standard Model top quark in pbar-p collisions at Sqrt(s)=1.8TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50pb-1. We have searched for t-tbar production in the dilepton and single-lepton decay channels, with and without tagging of b-quark jets. We observed 17 events with an expected background of 3.8+/-0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2.0E-6 (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199~+19_21 (stat.)+/- 22 (syst.)GeV/c**2 and its production cross section to be 6.4 +/- 2.2 pb.

0 data tables match query

Measurement of the top quark pair production cross-section in p anti-p collisions using multijet final states

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.
Phys.Rev.D 60 (1999) 012001, 1999.
Inspire Record 475565 DOI 10.17182/hepdata.42156

We have studied tbar-t production using multijet final states in pbar-p collisions at a center-of-mass energy of 1.8 TeV, with an integrated luminosity of 110.3 pb(-1). Each of the top quarks with these final states decays exclusively to a bottom quark and a W boson, with the W bosons decaying into quark-antiquark pairs. The analysis has been optimized using neural networks to achieve the smallest expected fractional uncertainty on the tbar-t production cross section, and yields a cross section of 7.1 +/- 2.8(stat.) +/- 1.5(syst.) pb, assuming a top quark mass of 172.1 GeV/c^(2). Combining this result with previous D0 measurements, where one or both of the W bosons decay leptonically, gives a tbar t production cross section of 5.9 +/- 1.2(stat) +/- 1.1(syst) pb.

0 data tables match query