| 231. |
- Abazov, V. M., et al.
(författare)
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Study of the decay Bs0→J/ψf2′(1525) in μ +μ -K +K - final states
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:9, s. 092011-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the decay Bs0→J/ψK +K - for invariant masses of the K +K - pair in the range 1.35<M(K +K -)<2GeV. The data sample corresponds to an integrated luminosity of 10.4fb -1 of pp̄ collisions at √s=1.96TeV accumulated with the D0 detector at the Fermilab Tevatron collider. From the study of the invariant mass and spin of the K +K - system, we find evidence for the two-body decay Bs0→J/ψf2′(1525) and measure the relative branching fraction of the decays Bs0→J/ψf2′(1525) and Bs0→J/ψ to be R f2′/=0.19±0.05(stat)±0.04(syst).
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| 232. |
- Abazov, V. M., et al.
(författare)
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Limits on anomalous trilinear gauge boson couplings from WW, WZ and Wγ production in pp- collisions at √s=1.96TeV
- 2012
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 718:2, s. 451-459
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Tidskriftsartikel (refereegranskat)abstract
- We present searches for the anomalous γWW and ZWW trilinear gauge boson couplings from WW and WZ production using lepton plus dijet final states and a combination with results from Wγ, WW, and WZ production with leptonic final states. The analyzed data correspond to up to 8.6fb -1 of integrated luminosity collected by the D0 detector in pp- collisions at s=1.96TeV. We set the most stringent limits at a hadron collider to date assuming two different relations between the anomalous coupling parameters δκ γ, λ, and δg1Z for a cutoff energy scale Λ=2TeV. The combined 68% C.L. limits are -0.057<δκ γ<0.154, -0.015<λ<0.028, and -0.008<δg1Z<0.054 for the LEP parameterization, and -0.007<δκ<0.081 and -0.017<λ<0.028 for the equal couplings parameterization. We also present the most stringent limits of the W boson magnetic dipole and electric quadrupole moments.
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| 233. |
- Abazov, V. M., et al.
(författare)
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Measurement of the differential gamma plus c-jet cross section and the ratio of differential gamma plus c and gamma plus b cross sections in p(p)over-bar collisions at root s=1.96 TeV
- 2013
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 719:4-5, s. 354-361
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the differential cross section d sigma/dp(T)(gamma) for the associated production of a c-quark jet and an isolated photon with rapidity vertical bar y(gamma)vertical bar < 1.0 and transverse momentum 30 < p(T)(gamma) < 300 GeV. The c-quark jets are required to have vertical bar y(jet)vertical bar < 1.5 and p(T)(jet) > 15 GeV. The ratio of differential cross sections for gamma + c to gamma + b production as a function of p(T)(gamma) is also presented. The results are based on data corresponding to an integrated luminosity of 8.7 fb(-1) recorded with the D0 detector at the Fermilab Tevatron p (p) over bar Collider at root s = 1.96 TeV. The obtained results are compared to next-to-leading order perturbative QCD calculations using various parton distribution functions, to predictions based on the k(T)-factorization approach, and to predictions from the SHERPA and PYTHIA Monte Carlo event generators.
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| 234. |
- Abazov, V. M., et al.
(författare)
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Measurement of the p(p)over-bar -> W plus b plus X production cross section at root s=1.96 TeV D0 Collaboration
- 2013
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 718:4-5, s. 1314-1320
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the cross section for W boson production in association with at least one b-quark jet in proton-antiproton collisions. The measurement is made using data corresponding to an integrated luminosity of 6.1fb-1 recorded with the D0 detector at the Fermilab Tevatron pp̄ Collider at s=1.96TeV. We measure an inclusive cross section of σ(W(→μν)+b+X)=1.04±0.05(stat.)±0.12(syst.) pb and σ(W(→eν)+b+X)=1.00±0.04(stat.)±0.12(syst.) pb in the phase space defined by pTν>25GeV, pTb-jet>20 GeV, |ηb-jet|<1.1, and a muon (electron) with pTℓ>20 GeV and |ημ|<1.7 (|ηe|<1.1 or 1.5<|ηe|<2.5). The combined result per lepton family is σ(W(→ℓν)+b+X)=1.05±0.12(stat.+syst.) pb for |ηℓ|<1.7. The results are in agreement with predictions from next-to-leading order QCD calculations using mcfm, σ(W+b){dot operator}B(W→ℓν)=1.34-0.34+0.41(syst.) pb, and also with predictions from the sherpa and madgraph Monte Carlo event generators.
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| 235. |
- Abazov, V. M., et al.
(författare)
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Measurement of the ratio of three-jet to two-jet cross sections in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 720:1-3, s. 6-12
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the ratio of multijet cross sections in p (p) over barp collisions at root s = 1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a data set corresponding to an integrated luminosity of 0.7 fb(-1) collected with the DO detector. The ratio of the inclusive three-jet to two-jet cross sections, R-3/2, has been measured as a function of the jet transverse momenta. The data are compared to QCD predictions in different approximations. Popular tunes of the PYriiiA event generator do not agree with the data, while SHERPA provides a reasonable description of the data. A perturbative QCD prediction in next-to-leading order in the strong coupling constant, corrected for non-perturbative effects, gives a good description of the data.
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| 236. |
- Abazov, V. M., et al.
(författare)
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Measurement of the semileptonic charge asymmetry in B-0 meson mixing with the D0 detector
- 2012
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:7, s. 072009-
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the semileptonic mixing asymmetry for B-0 mesons, a(sl)(d), using two independent decay channels: B-0 -> mu+D-X, with D- ->! K+ pi(-) pi(-); and B-0 -> mu+D*X-, with D*(-) -> (D) over bar (0) pi(-), (D) over bar (-)(0) K+ pi(-) (and charge conjugate processes). We use a data sample corresponding to 10.4 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV, collected with the D0 experiment at the Fermilab Tevatron collider. We extract the charge asymmetries in these two channels as a function of the visible proper decay length of the B-0 meson, correct for detector-related asymmetries using data-driven methods, and account for dilution from charge-symmetric processes using Monte Carlo simulation. The final measurement combines four signal visible proper decay length regions for each channel, yielding a(sl)(d) = [0.68 +/- 0: 45(stat) +/- 0.14(syst)]%. This is the single most precise measurement of this parameter, with uncertainties smaller than the current world average of B factory measurements.
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| 237. |
- Abazov, V. M., et al.
(författare)
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Combined search for the Higgs boson with the D0 experiment
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052011-
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Tidskriftsartikel (refereegranskat)abstract
- We perform a combination of searches for standard model Higgs boson production in p (p) over bar collisions recorded by the D0 detector at the Fermilab Tevatron Collider at a center of mass energy of root s = 1.96 TeV. The different production and decay channels have been analyzed separately, with integrated luminosities of up to 9.7 fb(-1) and for Higgs boson masses 90 <= M-H <= 200 GeV. We combine these final states to achieve optimal sensitivity to the production of the Higgs boson. We also interpret the combination in terms of models with a fourth generation of fermions, and models with suppressed Higgs boson couplings to fermions. The result excludes a standard model Higgs boson at 95% C.L. in the ranges 90 < M-H < 101 GeV and 157 < M-H < 178 GeV, with an expected exclusion of 155 < M-H < 175 GeV. In the range 120 < M-H < 145 GeV, the data exhibit an excess over the expected background of up to 2 standard deviations, consistent with the presence of a standard model Higgs boson of mass 125 GeV.
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| 238. |
- Abazov, V. M., et al.
(författare)
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Measurement of the combined rapidity and p(T) dependence of dijet azimuthal decorrelations in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 721:4-5, s. 212-219
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first combined measurement of the rapidity and transverse momentum dependence of dijet azimuthal decorrelations, using the recently proposed quantity R-Delta phi. The variable R-Delta phi measures the fraction of the inclusive dijet events in which the azimuthal separation of the two jets with the highest transverse momenta is less than a specified value of the parameter Delta phi(max). The quantity R-Delta phi is measured in p (p) over bar collisions at root s = 1.96 TeV, as a function of the dijet rapidity interval, the total scalar transverse momentum, and Delta phi(max). The measurement uses an event sample corresponding to an integrated luminosity of 0.7 fb(-1) collected with the DO detector at the Fermilab Tevatron Collider. The results are compared to predictions of a perturbative QCD calculation at next-to-leading order in the strong coupling with corrections for non-perturbative effects. The theory predictions describe the data well, except in the kinematic region of large dijet rapidity intervals and small Delta phi(max).
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| 239. |
- Abazov, V. M., et al.
(författare)
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Measurement of the differential cross sections for isolated direct photon pair production in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 725:1-3, s. 6-14
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of direct photon pair production cross sections using 8.5 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron p (p) over bar collider. The results are presented as differential distributions of the photon pair invariant mass d sigma/dM(gamma gamma), pair transverse momentum d sigma/dp(T)(gamma gamma) azimuthal angle between the photons d sigma/d Delta(phi)(gamma gamma), and polar scattering angle in the Collins-Soper frame d sigma/d vertical bar cos theta*vertical bar. Measurements are performed for isolated photons with transverse momenta p(T)(gamma) > 18 (17) GeV for the leading (next-to-leading) photon in P-T, pseudorapidities vertical bar eta(gamma)vertical bar < 0.9, and a separation in eta-phi space Delta R-gamma gamma > 0.4. We present comparisons with the predictions from Monte Carlo event generators DIPHOX and RESBOS implementing QCD calculations at next-to-leading order, 2 gamma NNLO at next-to-next-to-leading order, and SHERPA using matrix elements with higher-order real emissions matched to parton shower.
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| 240. |
- Abazov, V. M., et al.
(författare)
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Measurement of the ratio of differential cross sections sigma(p(p)over-bar -> Z + b jet)/sigma(p(p)over-bar -> Z + jet) in p(p)over-bar collisions at root s = 1.96 TeV
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:9, s. 092010-
-
Tidskriftsartikel (refereegranskat)abstract
- We measure the ratio of cross sections, sigma(p (p) over bar -> Z + b jet)/sigma(p (p) over bar -> Z + jet), for associated production of a Z boson with at least one jet. The ratio is also measured as a function of the Z boson transverse momentum, jet transverse momentum, jet pseudorapidity, and the azimuthal angle between the Z boson with respect to the highest p(T) b tagged jet. These measurements use data collected by the D0 experiment in Run II of Fermilab's Tevatron p (p) over bar Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of 9.7 fb(-1). The results are compared to predictions from next-to-leading order calculations and various Monte Carlo event generators.
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