Z. H. Zhu

Publications (66)105 Total impact

• Article: Halloysite-Nanotube-Supported Ru Nanoparticles for Ammonia Catalytic Decomposition to Produce CO(x)-Free Hydrogen

  L. Wang, J. L. Chen, L. Ge, Z. H. Zhu, V. Rudolph
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  ABSTRACT: Natural halloysite nanotubes (HNTs) were employed as the support of Ru nanoparticles, and the corresponding activity was tested in an ammonia catalytic decomposition reaction for the production of CO(x)-free hydrogen as the feed gas for proton exchange membrane fuel cell. N(2) physisorption, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, hydrogen temperature-programmed reduction, and X-ray photoelectron spectroscopy were used to investigate the morphology and structure of HNTs and Ru/HNTs. The results show that HNTs possess a suitable specific surface area and pore volume, as well as a tubular structure with good thermal stability. The supported Ru nanoparticles are mostly located on the external surface of HNTs, whereas the interaction is weak between Ru particles and Si-O groups on the surface of HNTs. The dispersion of Ru particles decreases with the increase of the Ru loading content. The ammonia conversion increases with the Ru loading content from 0.3 to 5.6 wt %, and the turnover frequency of ammonia reaches a peak value at a Ru loading content of 1.1 wt %.
  Energy & Fuels. 01/2011; 25(8):3408-3416.
• Article: tt̅ production cross section in pp̅ collisions at √s=1.8TeV

  V. M. Abazov, B. Abbott, A. Abdesselam, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, S. N. Ahmed, G. D. Alexeev, [......], H. Zheng, B. Zhou, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: Results are presented on a measurement of the tt̅ pair production cross section in pp̅ collisions at √s=1.8TeV from nine independent decay channels. The data were collected by the DØ experiment during the 1992–1996 run of the Fermilab Tevatron Collider. A total of 80 candidate events is observed with an expected background of 38.8±3.3 events. For a top quark mass of 172.1GeV/c2, the measured cross section is 5.69±1.21(stat)±1.04(syst)pb.
  Phys. Rev. D. 01/2003; 67(1).
• Article: Measurement of the angular distribution of electrons from W⃗eν decays observed in pp̅ collisions at √s=1.8 TeV

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, G. A. Alves, N. Amos, E. W. Anderson, M. M. Baarmand, [......], M. Zanabria, H. Zheng, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We present the first measurement of the electron angular distribution parameter α2 in W⃗eν events produced in proton-antiproton collisions as a function of the W boson transverse momentum. Our analysis is based on data collected using the DØ 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±α1cosθ*+α2cos2θ*), where θ* is the polar angle of the electron in the Collins-Soper frame. In the presence of QCD corrections, the parameters α1 and α2 become functions of pTW, 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.
  Phys. Rev. D. 03/2001; 63(7).
• Article: Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV.

  B Abbott, M Abolins, V Abramov, B S Acharya, D L Adams, M Adams, G A Alves, N Amos, E W Anderson, M M Baarmand, [......], M Zanabria, H Zheng, Z Zhou, Z H Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, E G Zverev, A Zylberstejn
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  ABSTRACT: We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.
  Physical Review Letters 03/2001; 86(10):1955-60. · 7.37 Impact Factor
• Article: Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV.

  B Abbott, M Abolins, V Abramov, B S Acharya, D L Adams, M Adams, G A Alves, N Amos, E W Anderson, M M Baarmand, [......], M Zanabria, H Zheng, Z Zhou, Z H Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, E G Zverev, A Zylberstejn
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  ABSTRACT: The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.
  Physical Review Letters 03/2001; 86(12):2523-8. · 7.37 Impact Factor
• Source

  Available from: Horst D Wahl

  Article: Search for large extra dimensions in dielectron and diphoton production.

  B Abbott, M Abolins, V Abramov, B S Acharya, D L Adams, M Adams, G A Alves, N Amos, E W Anderson, M M Baarmand, [......], M Zanabria, H Zheng, Z Zhou, Z H Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, E G Zverev, A Zylberstejn
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  ABSTRACT: We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.
  Physical Review Letters 03/2001; 86(7):1156-61. · 7.37 Impact Factor
• Article: Search for new physics in eμX data at DØ using SLEUTH: A quasi-model-independent search strategy for new physics

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, G. A. Alves, N. Amos, E. W. Anderson, M. M. Baarmand, [......], M. Zanabria, H. Zheng, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We present a quasi-model-independent search for the physics responsible for electroweak symmetry breaking. We define final states to be studied, and construct a rule that identifies a set of relevant variables for any particular final state. A new algorithm (“SLEUTH”) searches for regions of excess in those variables and quantifies the significance of any detected excess. After demonstrating the sensitivity of the method, we apply it to the semi-inclusive channel eμX collected in 108 pb-1 of pp̅ collisions at √s=1.8 TeV at the DØ experiment during 1992–1996 at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample.
  Phys. Rev. D. 10/2000; 62(9).
• Article: Limits on anomalous WWγ and WWZ couplings from WW/WZ⃗eνjj production

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, S. Ahn, V. Akimov, G. A. Alves, N. Amos, [......], M. Zanabria, H. Zheng, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: Limits on anomalous WWγ and WWZ couplings are presented from a study of WW/WZ⃗eνjj events produced in pp̅ collisions at √s=1.8 TeV. Results from the analysis of data collected using the DØ detector during the 1993–1995 Tevatron collider run at Fermilab are combined with those of an earlier study from the 1992–1993 run. A fit to the transverse momentum spectrum of the W boson yields direct limits on anomalous WWγ and WWZ couplings. With the assumption that the WWγ and WWZ couplings are equal, we obtain -0.34<λ<0.36 (with Δκ=0) and -0.43<Δκ<0.59 (with λ=0) at the 95% confidence level for a form-factor scale Λ=2.0 TeV.
  Phys. Rev. D. 08/2000; 62(5).
• Article: The b

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, V. Akimov, G. A. Alves, N. Amos, E. W. Anderson, [......], M. Zanabria, H. Zheng, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We present measurements of the b boverline production cross section and angular correlations using the DØ detector at the Fermilab Tevatron p poverline Collider operating at /sqrt(s) = 1.8 TeV. The /b quark production cross section for yb<1.0 and pTb>6 GeV//c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading order QCD calculation of heavy flavor production but are greater than the central values of these predictions. The angular correlations between /b and boverline quarks, measured from the azimuthal opening angle between their decay muons, also agree in shape with the next-to-leading order QCD prediction.
  Physics Letters B 07/2000; 487:264-272. · 3.95 Impact Factor
• Source

  Available from: Horst D Wahl

  Article: Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV.

  B Abbott, M Abolins, V Abramov, B S Acharya, D L Adams, M Adams, V Akimov, G A Alves, N Amos, E W Anderson, [......], M Zanabria, H Zheng, Z Zhou, Z H Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, E G Zverev, A Zylberstejn
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  ABSTRACT: Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.
  Physical Review Letters 07/2000; 84(25):5722-7. · 7.37 Impact Factor
• Article: Spin Correlation in tt¯ Production from pp¯ Collisions at √s = 1.8 TeV

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, V. Akimov, G. A. Alves, N. Amos, E. W. Anderson, [......], M. Zanabria, H. Zheng, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: The D0 collaboration has performed a study of spin correlation in tt¯ production for the process tt¯-->bW+b¯W-, where the W bosons decay to eν or μν. A sample of six events was collected during an exposure of the D0 detector to an integrated luminosity of approximately 125 pb-1 of s = 1.8 TeV pp¯ collisions. The standard model (SM) predicts that the short lifetime of the top quark ensures the transmission of any spin information at production to the tt¯ decay products. The degree of spin correlation is characterized by a correlation coefficient κ. We find that κ>-0.25 at the 68% confidence level, in agreement with the SM prediction of κ = 0.88.
  Physical Review Letters 06/2000; 85:256-261. · 7.37 Impact Factor
• Article: Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV.

  B Abbott, M Abolins, V Abramov, B S Acharya, D L Adams, M Adams, S Ahn, V Akimov, G A Alves, N Amos, [......], M Zanabria, H Zheng, Z Zhou, Z H Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, E G Zverev, A Zylberstejn
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  ABSTRACT: We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.
  Physical Review Letters 06/2000; 84(25):5710-5. · 7.37 Impact Factor
• Article: Isolated Photon Cross Section in pp¯ Collisions at √s = 1.8 TeV

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, S. Ahn, V. Akimov, G. A. Alves, N. Amos, [......], M. Zanabria, H. Zheng, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, V. Zutshi, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We report a new measurement of the cross section for the production of isolated photons with transverse energies ( EγT) above 10 GeV and pseudorapidities \|η\|<2.5 in pp¯ collisions at 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 QCD calculation for EγT>~36 GeV.
  Physical Review Letters 02/2000; 84:2786-2791. · 7.37 Impact Factor
• Article: Measurement of W and Z boson production cross sections in pp̅ collisions at √s=1.8 TeV

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, G. A. Alves, N. Amos, [......], Y. Yu, B. Zhang, Y. Zhou, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: DØ has measured the inclusive production cross section of W and Z bosons in a sample of 13 pb-1 of data collected at the Fermilab Tevatron. The cross sections, multiplied by their leptonic branching fractions, for production in pp̅ collisions at √s=1.8 TeV are σWB(W⃗eν)=2.36±0.02±0.08±0.13 nb, σWB(W⃗μν)=2.09±0.06±0.22±0.11 nb, σZB(Z⃗e+e-)=0.218±0.008±0.008±0.012 nb, and σZB(Z⃗μ+μ-)=0.178±0.022±0.021±0.009 nb, where the first uncertainty is statistical and the second systematic; the third reflects the uncertainty in the integrated luminosity. For the combined electron and muon analyses, we find σWB(W⃗lν)/σZB(Z⃗l+l-)=10.90±0.52. Assuming standard model couplings, we use this result to determine the width of the W boson, and obtain Γ(W)=2.044±0.097 GeV.
  Phys. Rev. D. 08/1999; 60(5).
• Article: Measurement of the top quark mass in the dilepton channel

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, H. Aihara, G. A. Alves, [......], Y. Yu, B. Zhang, Y. Zhou, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We report a measurement of the top quark mass using six candidate events for the process pp̅ →tt̅ +X⃗l+νbl-ν̅ b̅ +X, observed in the D0 experiment at the Fermilab pp̅ collider. Using maximum likelihood fits to the dynamics of the decays, we measure a mass for the top quark of mt=168.4±12.3(stat)±3.6(syst) Gev. We combine this result with our previous measurement in the tt̅ →l+jets channel to obtain mt=172.1±7.1 GeV as the best value of the mass of the top quark measured by D0.
  Phys. Rev. D. 07/1999; 60(5).
• Article: Measurement of the top quark pair production cross section in pp̅ collisions using multijet final states

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, H. Aihara, G. A. Alves, [......], Y. Yu, B. Zhang, Y. Zhou, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We have studied tt̅ production using multijet final states in pp̅ 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 tt̅ 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/c2. Combining this result with previous DØ measurements, where one or both of the W bosons decay leptonically, gives a tt̅ production cross section of 5.9±1.2 (stat)±1.1 (syst) pb.
  Phys. Rev. D. 05/1999; 60(1).
• Article: Small Angle J/ψ Production in pp¯ Collisions at √s = 1.8 TeV

  B. Abbott, M. Abolins, V. Abramov, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, H. Aihara, G. A. Alves, [......], Y. Yu, B. Zhang, Y. Zhou, Z. Zhou, Z. H. Zhu, M. Zielinski, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: This paper presents the first measurement of inclusive J/ψ production cross section in the forward pseudorapidity region 2.5<=\|ηJ/ψ\|<=3.7 in pp¯ collisions at s = 1.8 TeV. The results are based on 9.8 pb-1 of data collected using the D0 detector at the Fermilab Tevatron Collider. The inclusive J/ψ cross section for transverse momenta between 1 and 16 GeV/ c is compared with theoretical models of charmonium production.
  Physical Review Letters 12/1998; 82:35-40. · 7.37 Impact Factor
• Article: Direct measurement of the top quark mass by the DØ Collaboration

  B. Abbott, M. Abolins, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, H. Aihara, G. A. Alves, N. Amos, [......], P. Yepes, C. Yoshikawa, S. Youssef, J. Yu, Y. Yu, Z. H. Zhu, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: We determine the top quark mass mt using tt̅ pairs produced in the DØ detector by √s=1.8TeV pp̅ collisions in a 125pb-1 exposure at the Fermilab Tevatron. We make a two constraint fit to mt in tt̅ →bW+b̅ W- final states with one W boson decaying to qq̅ and the other to eν or μν. Likelihood fits to the data yield mt(l+jets)=173.3±5.6 (stat) ± 5.5 (syst) GeV/c2. When this result is combined with an analysis of events in which both W bosons decay into leptons, we obtain mt=172.1±5.2 (stat)±4.9 (syst) GeV/c2. An alternate analysis, using three constraint fits to fixed top quark masses, gives mt(l+jets)=176.0±7.9 (stat)±4.8 (syst) GeV/c2, consistent with the above result. Studies of kinematic distributions of the top quark candidates are also presented. 14.65.Ha, 13.85.Ni, 13.85.Qk
  Phys. Rev. D. 07/1998; 58(5).
• Article: Determination of the mass of the W boson using the D∅ detector at the Fermilab Tevatron

  B. Abbott, M. Abolins, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, H. Aihara, G. A. Alves, E. Amidi, [......], C. Yoshikawa, S. Youssef, J. Yu, Y. Yu, Q. Zhu, Z. H. Zhu, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: A measurement of the mass of the W boson is presented which is based on a sample of 5982 W⃗eν decays observed in pp̅ collisions at √s=1.8 TeV with the D∅ detector during the 1992–1993 run. From a fit to the transverse mass spectrum, combined with measurements of the Z boson mass, the W boson mass is measured to be MW=80.350±0.140(stat)±0.165(syst)±0.160(scale) GeV/c2. Detailed discussions of the determination of the absolute energy scale, the measured efficiencies, and all systematic uncertainties are presented.
  Phys. Rev. D. 06/1998; 58(1).
• Article: Search for top squark pair production in the dielectron channel

  S. Abachi, B. Abbott, M. Abolins, B. S. Acharya, I. Adam, D. L. Adams, M. Adams, S. Ahn, H. Aihara, G. Álvarez, [......], C. Yoshikawa, S. Youssef, J. Yu, Y. Yu, Q. Zhu, Z. H. Zhu, D. Zieminska, A. Zieminski, E. G. Zverev, A. Zylberstejn
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  ABSTRACT: This report describes the first search for top squark pair production in the channel t1t̃̅ 1→bb̅ χ̃1+χ̃1-→ee+jets+ET using 74.9±8.9 pb-1 of data collected using the DØ detector. A 95% confidence level upper limit on σ⋅B is presented. The limit is above the theoretical expectation for σ⋅B for this process, but does show the sensitivity of the current DØ data set to a particular topology for new physics.
  Phys. Rev. D. 12/1997; 57(1).