Search for W′ boson production in the W′ → t over(b, ̄) decay channel
Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 641:6 (2006) 423-431
Abstract:
We present a search for the production of a new heavy gauge boson W′ that decays to a top quark and a bottom quark. We have analyzed 230 pb-1 of data collected with the DØ detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events above the standard model expectation is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W′ bosons times branching ratio to top quarks at the 95% confidence level for several different W′ boson masses. We exclude masses between 200 and 610 GeV for a W′ boson with standard-model-like couplings, between 200 and 630 GeV for a W′ boson with right-handed couplings that is allowed to decay to both leptons and quarks, and between 200 and 670 GeV for a W′ boson with right-handed couplings that is only allowed to decay to quarks. © 2006 Elsevier B.V. All rights reserved.Search for particles decaying into a Z boson and a photon in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV
Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 641:6 (2006) 415-422
Abstract:
We present the results of a search for a new particle X produced in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV and subsequently decaying to Zγ. The search uses 0.3 fb-1 of data collected with the DØ detector at the Fermilab Tevatron Collider. We set limits on the production cross section times the branching fraction σ (p over(p, ̄) → X) × B (X → Z γ) that range from 0.4 to 3.5 pb at the 95% C.L. for X with invariant masses between 100 and 1000 GeV / c2, over a wide range of X decay widths. © 2006 Elsevier B.V. All rights reserved.Measurement of the tt̄ production cross section in pp̄ collisions at s=1.96TeV using lepton+jets events with jet probability b-tagging
Physical Review D Particles Fields Gravitation and Cosmology 74:7 (2006)
Abstract:
We present a measurement of the tt̄ production cross section using events with one charged lepton and jets from pp̄ collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks coming from the event interaction vertex is applied to identify b quarks from top decay. Using 318pb-1 of data collected with the CDF II detector, we measure the tt̄ production cross section in events with at least one restrictive (tight) b-tagged jet and obtain 8.9-1.0+1.0(stat)-1.0+1.1(syst)pb. The cross section value assumes a top quark mass of mt=178GeV/c2 in the acceptance corrections. The dependence of the cross section on mt is presented in the paper. This result is consistent with other CDF measurements of the tt̄ cross section using different samples and analysis techniques, and has similar systematic uncertainties. We have also performed consistency checks by using the b-tagging probability function to vary the signal-to-background ratio and also using events that have at least two b-tagged jets. © 2006 The American Physical Society.Search for associated Higgs boson production WH→WWW *→l±νl′±ν′+X in pp̄ collisions at s=1.96TeV
Physical Review Letters 97:15 (2006)
Abstract:
We present a search for associated Higgs boson production in the process pp̄→WH→WWW*→l±νl′±ν′ +X in final states containing two like-sign isolated electrons or muons (e±e±, e±μ±, or μ±μ±). The search is based on D0 run II data samples corresponding to integrated luminosities of 360-380pb-1. No excess is observed over the predicted standard model background. We set 95% C.L. upper limits on σ(pp̄→WH) ×Br(H→WW*) between 3.2 and 2.8 pb for Higgs boson masses from 115 to 175 GeV. © 2006 The American Physical Society.Search for neutral, long-lived particles decaying into two muons in pp[over] collisions at sqrt[s]=1.96 TeV.
Phys Rev Lett 97:16 (2006) 161802