SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Park Jong Y) "

Sökning: WFRF:(Park Jong Y)

Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Abazov, V. M., et al. (författare)
  • Measurement of the t-channel single top quark production cross section
  • 2010
  • Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 682:4-5, s. 363-369
  • Tidskriftsartikel (refereegranskat)abstract
    • The DO Collaboration reports direct evidence for electroweak production of single top quarks through the t-channel exchange of a virtual W boson. This is the first analysis to isolate an individual single top quark production channel. We select events containing an isolated electron or muon, missing transverse energy, and two, three or four jets from 2.3 fb(-1) of p (p) over bar collisions at the Fermilab Tevatron Collider. One or two of the jets are identified as containing a b hadron. We combine three multivariate techniques optimized for the t-channel process to measure the t- and s-channel cross sections simultaneously. We measure cross sections of 3.14(-0.80)(+0.94) pb for the t-channel and 1.05 +/- 0.81 pb for the s-channel. The measured t-channel result is found to have a significance of 4.8 standard deviations and is consistent with the standard model prediction.
  •  
2.
  • Abazov, V. M., et al. (författare)
  • Constraints on Models for the Higgs Boson with Exotic Spin and Parity in VH -> Vb(b)over-bar Final States
  • 2014
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:16, s. 161802
  • Tidskriftsartikel (refereegranskat)abstract
    • We present constraints on models containing non-standard-model values for the spin J and parity P of the Higgs boson H in up to 9.7 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. These are the first studies of Higgs boson J(P) with fermions in the final state. In the ZH -> llb (b) over bar, WH -> l nu b (b) over barb, and ZH -> nu nu b (b) over bar final states, we compare the standard model (SM) Higgs boson prediction, J(P) = 0(+), with two alternative hypotheses, J(P) = 0(-) and J(P) = 2(+). We use a likelihood ratio to quantify the degree to which our data are incompatible with non-SM J(P) predictions for a range of possible production rates. Assuming that the production rate in the signal models considered is equal to the SM prediction, we reject the J(P) = 0(-) and J(P) = 2(+) hypotheses at the 97.6% CL and at the 99.0% CL, respectively. The expected exclusion sensitivity for a J(P) = 0(-)(J(P) = 2(+)) state is at the 99.86% (99.94%) CL. Under the hypothesis that our data are the result of a combination of the SM-like Higgs boson and either a J(P) = 0(-) or a J(P) = 2(+) signal, we exclude a J(P) = 0(-) fraction above 0.80 and a JP = 2(+) fraction above 0.67 at the 95% CL. The expected exclusion covers J(P) = 0(-)(J(P) = 2(+)) fractions above 0.54 (0.47).
  •  
3.
  • Abazov, V. M., et al. (författare)
  • Determination of the strong coupling constant from the inclusive jet cross section in pp collisions at s=1.96 TeV
  • 2009
  • Ingår i: PHYS REV D. - 1550-7998. ; 80:11, s. 111107
  • Tidskriftsartikel (refereegranskat)abstract
    • We determine the strong coupling constant alpha(s) and its energy dependence from the p(T) dependence of the inclusive jet cross section in pp collisions at s=1.96 TeV. The strong coupling constant is determined over the transverse momentum range 50 < p(T)< 145 GeV. Using perturbative QCD calculations to order O(alpha(3)(s)) combined with O(alpha(4)(s)) contributions from threshold corrections, we obtain alpha(s)(M-Z)=0.1161(-0.0048)(+0.0041). This is the most precise result obtained at a hadron-hadron collider.
  •  
4.
  • Abazov, V. M., et al. (författare)
  • Double parton interactions in gamma+3 jet and gamma plus b/c jet+2 jet events in p(p)over-bar collisions at root s=1.96 TeV
  • 2014
  • Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:7, s. 072006
  • Tidskriftsartikel (refereegranskat)abstract
    • We determine the fraction of events with double parton (DP) Scattering in a single p (p) over bar collisions at root s = 1.96 TeV in gamma + 3 jet and gamma + b/c jet + 2 jet events collected with the D0 detector and corresponding to an integrated luminosity of about 8.7 fb(-1). The DP fractions and effective cross sections (sigma(eff)) are measured for both event samples using the same kinematic selections. The measured DP fractions range from 0.21 to 0.17, with effective cross sections in the gamma + 3 jet and gamma + b/cjet + 2 jet samples of sigma(incl)(eff) = 12.7 +/- 0.2(stat) +/- 1.3(syst) mb and sigma(HF)(eff) = 14.6 +/- 0.6(stat) +/- 3.2(syst) mb, respectively.
  •  
5.
  • Abazov, V. M., et al. (författare)
  • Electron and photon identification in the Do experiment
  • 2014
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. - 0168-9002 .- 1872-9576. ; 750, s. 78-95
  • Tidskriftsartikel (refereegranskat)abstract
    • The electron and photon reconstruction and identification algorithms used by the DO Collaboration at the Fermilab Tevatron collider are described. The determination of the electron energy scale and resolution is presented. Studies of the performance of the electron and photon reconstruction and identification are summarized. The results are based on measurements of Z boson decay events of Z ee and Z gamma ll(i=e mu) collected in pp(over bar) collisions at a center- of- mass energy of 1.96 TeV using an integrated luminosity of up to10 fb(-1.)
  •  
6.
  • Abazov, V. M., et al. (författare)
  • Evidence for s-channel single top quark production in p(p)over-bar collisions at root s=1.96 TeV
  • 2013
  • Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 726:4-5, s. 656-664
  • Tidskriftsartikel (refereegranskat)abstract
    • We present measurements of the cross sections for the two main production modes of single top quarks in p (p) over bar collisions at root s = 1.96 TeV in the Run II data collected with the DO detector at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.7 fb(-1). The s-channel cross section is measured to be sigma(p (p) over bar -> tb + X) = 1.10(-0.31)(+0.33) pb with no assumptions on the value of the t-channel cross section. Similarly, the t-channel cross section is measured to be sigma(p (p) over bar -> tqb + X) = 3.07(-0.49)(+0.54) pb. We also measure the s + t combined cross section as sigma(p (p) over bar -> tb + X, tqb + X) = 4.11(-0.55)(+0.60) ph and set a lower limit on the CKM matrix element vertical bar V-tb vertical bar> 0.92 at 95% C.L., assuming mt = 172.5 GeV. The probability to measure a cross section for the s channel at the observed value or higher in the absence of signal is 1.0 x 10(-4), corresponding to a significance of 3.7 standard deviations. 
  •  
7.
  • Abazov, V. M., et al. (författare)
  • Improved b quark jet identification at the D0 experiment
  • 2014
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. - 0168-9002 .- 1872-9576. ; 763, s. 290-303
  • Tidskriftsartikel (refereegranskat)abstract
    • The ability to identify jets which originated from b quarks is an important tool of the physics program of the D0 experiment at the Fermilab Tevatron p (p) over bar collider. This paper describes a new algorithm designed to select jets originating from b quarks while suppressing the contamination caused by jets from other quark flavors and gluons. Additionally, a new technique, the SystemN method, for determining the misidentification rate directly from data is presented. (C) 2014 Elsevier B.V. All rights reserved.
  •  
8.
  • Abazov, V. M., et al. (författare)
  • Jet energy scale determination in the DO experiment
  • 2014
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. - 0168-9002 .- 1872-9576. ; 763, s. 442-475
  • Tidskriftsartikel (refereegranskat)abstract
    • The calibration of jet energy measured in the DO detector is presented, based on p (p) over bar collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider, jet energies are measured using a sampling calorimeter composed of uranium and liquid argon as the passive and active media, respectively. This paper describes the energy calibration of jets performed with gamma+jet, Z+jet and dilet events, with jet transverse momentum p(T) > 6 GeV and pseudorapidity range vertical bar eta vertical bar < 3.6, The corrections are measured separately for data and simulation, achieving a precision of 1.4-1.8% for jets in the central part of the calorimeter ancl up to 3.5% for the jets with pseudorapidity vertical bar eta vertical bar = 3.0. Specific corrections are extracted to enhance the description of jet energy in simulation and in particular of the effects due to the flavor of the parton originating the jet, correcting biases up to 3-4% in jets with low PT originating from gluons and up to 6-8% in jets from b quarks. Published by Elsevier B.V.
  •  
9.
  • Abazov, V. M., et al. (författare)
  • Measurement of Associated Production of Z Bosons with Charm Quark Jets in p(p)over-bar Collisions at root s = 1.96 TeV
  • 2014
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:4, s. 042001
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the first measurements of the ratios of cross sections sigma(p (p) over bar -> Z + c jet)/sigma(p (p) over bar -> Z + jet) and sigma(p (p) over bar -> Z + jet)/sigma(p (p) over bar -> Z + b jet) for the associated production of a Z boson with at least one charm or bottom quark jet. Jets have transverse momentum p(T)(jet) > 20 GeV and pseudorapidity vertical bar eta(jet)vertical bar < 2.5. These cross section ratios are measured differentially as a function of jet and Z boson transverse momenta, based on 9.7 fb(-1) of p<(p)over bar> collisions collected with the D0 detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. The measurements show significant deviations from perturbative QCD calculations and predictions from various event generators.
  •  
10.
  • Abazov, V. M., et al. (författare)
  • Measurement of differential tt production cross sections in pp collisions
  • 2014
  • Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:9, s. 092006
  • Tidskriftsartikel (refereegranskat)abstract
    • The production of top quark-antiquark pair events in pp collisions at root s= 1.96 TeV is studied as a function of the transverse momentum and absolute value of the rapidity of the top quarks as well as of the invariant mass of the tt pair. We select events containing an isolated lepton, a large imbalance in transverse momentum, and four or more jets with at least one jet identified as originating from a b quark. The data sample corresponds to 9.7 fb(-1) of integrated luminosity recorded with the D0 detector during Run II of the Fermilab Tevatron Collider. Observed differential cross sections are consistent with standard model predictions.
  •  
Skapa referenser, mejla, bekava och länka
 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy