| 1. |
- Abazov, V. M., et al.
(författare)
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Measurement of dijet azimuthal decorrelations at central rapidities in p(p)over-bar collisions at root s=1.96 TeV
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:22, s. 221801-
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Tidskriftsartikel (refereegranskat)abstract
- Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the D0 detector in p (p) over bar collisions at a center-of-mass energy root s=1.96 TeV. The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb(-1). Azimuthal correlations are stronger at larger transverse momenta. These are well described in perturbative QCD at next-to-leading order in the strong coupling constant, except at large azimuthal differences where contributions with low transverse momentum are significant.
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| 2. |
- Abazov, V. M., et al.
(författare)
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Measurement of sigma(p(p)over-bar -> Z)center dot Br(Z ->tau tau) at root s=1.96 TeV
- 2005
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Ingår i: Physical Review D. Particles and fields. - 0556-2821 .- 1089-4918. ; 71:7, s. 072004-
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the cross section for Z production times the branching fraction to tau leptons, sigma.Br(Z ->tau(+)tau(-)), in p (p) over bar collisions at root s=1.96 TeV in the channel in which one tau decays into mu nu(mu)nu(tau), and the other into hadrons+nu(tau) or e nu(e)nu(tau). The data sample corresponds to an integrated luminosity of 226 pb(-1) collected with the D0 detector at the Fermilab Tevatron collider. The final sample contains 2008 candidate events with an estimated background of 55%. From this we obtain sigma.Br(Z ->tau(+)tau(-)) = 237 +/- 15(stat)+/- 18(sys)+/- 15(lum)pb, in agreement with the standard model prediction.
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| 3. |
- Abazov, V. M., et al.
(författare)
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Measurement of the B-s(0) lifetime in the exclusive decay channel B-s(0)-> J/psi phi
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:4, s. 042001-
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Tidskriftsartikel (refereegranskat)abstract
- Using the exclusive decay B-s(0)-->J/psi(mu(+)mu(-))phi(K+K-), we report the most precise single measurement of the B-s(0) lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb(-1) collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2004. We reconstruct 337 signal candidates, from which we extract the B-s(0) lifetime, tau(B-s(0))=1.444(-0.090)(+0.098)(stat)+/-0.020(sys) ps. We also report a measurement for the lifetime of the B-0 meson using the exclusive decay B-0-->J/psi(mu(+)mu(-))K-*0(892)(K(+)pi(-)). We reconstruct 1370 signal candidates, obtaining tau(B-0)=1.473(-0.050)(+0.052)(stat)+/-0.023(sys) ps, and the ratio of lifetimes, tau(B-s(0))/tau(B-0)=0.980(-0.071)(+0.076)(stat)+/-0.003(sys).
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| 4. |
- Abazov, V. M., et al.
(författare)
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Measurement of the Lambda(0)(b) lifetime in the decay Lambda(0)(b)-> J/psi Lambda(0) with the D0 detector
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:10, s. 102001-
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the Lambda(b)(0) lifetime in the exclusive decay channel Lambda(b)(0)-> J/psi Lambda(0), with J/psi ->mu(+)mu(-) and Lambda(0)-> p pi(-), the B-0 lifetime in the decay B-0-> J/psi K-S(0) with J/psi ->mu(+)mu(-) and K-S(0)->pi(+)pi(-), and the ratio of these lifetimes. The analysis is based on approximately 250 pb(-1) of data recorded with the D0 detector in p (p) over bar collisions at root s = 1.96 TeV. The Lambda(b)(0) lifetime is determined to be tau(Lambda(b)(0))=1.22(-0.18)(+0.22)(stat)+/- 0.04(syst) ps, the B-0 lifetime tau(B-0)=1.40(-) (+0.11)(0.10)(stat)+/- 0.03(syst) ps, and the ratio tau(Lambda(b)(0))/tau(B-0)=0.87(-) (+0.17)(0.14)(stat)+/- 0.03(syst). In contrast with previous measurements using semileptonic decays, this is the first determination of the Lambda(b)(0) lifetime based on a fully reconstructed decay channel.
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| 5. |
- Abazov, V. M., et al.
(författare)
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Measurement of the ratio of B+ and B-0 meson lifetimes
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:18, s. 182001-
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Tidskriftsartikel (refereegranskat)abstract
- The ratio of the B+ and B-0 meson lifetimes was measured using data collected in 2002-2004 by the D0 experiment in Run II of the Fermilab Tevatron Collider. These mesons were reconstructed in B→μ(+)ν D*-X decays, which are dominated by B-0 and B→μ(+)ν(D) over bar X-0 decays, which are dominated by B+. The ratio of lifetimes is measured to be τ(+)/τ(0)=1.080± 0.016(stat)± 0.014(syst).
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| 6. |
- Abazov, V. M., et al.
(författare)
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Measurement of the ratio of inclusive cross sections sigma(p(p)over-bar -> Z plus b jet)/sigma(p(p)over-bar -> Z plus jet) at root s=1.96 TeV
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:16, s. 161801-
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Tidskriftsartikel (refereegranskat)abstract
- Using the data collected with the D0 detector at root s=1.96 TeV, for integrated luminosities of about 180 pb(-1), we have measured the ratio of inclusive cross sections for p(p) over bar -> Z+b jet to p(p) over bar -> Z+jet production. The inclusive Z+b-jet reaction is an important background to searches for the Higgs boson in associated ZH production at the Fermilab Tevatron collider. Our measurement is the first of its kind, and relies on the Z -> e(+)e(-) and Z ->mu(+)mu(-) modes. The combined measurement of the ratio yields 0.021 +/- 0.005 for hadronic jets with transverse momenta p(T)> 20 GeV/c and pseudorapidities vertical bar eta vertical bar < 2.5, consistent with next-to-leading-order predictions of the standard model.
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| 7. |
- Abazov, V. M., et al.
(författare)
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Measurement of the WW production cross section in p(p)over-bar collisions at root(s)over-bar=1.96 TeV
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:15, s. 151801-
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the W boson pair-production cross section in p(p) over bar collisions at a center-of-mass energy of root s=1.96 TeV. The data, collected with the Run II D0 detector at Fermilab, correspond to an integrated luminosity of 224-252 pb(-1) depending on the final state (ee, e mu, or mu mu). We observe 25 candidates with a background expectation of 8.1 +/- 0.6(stat)+/- 0.6(syst)+/- 0.5(lum) events. The probability for an upward fluctuation of the background to produce the observed signal is 2.3x10(-7), equivalent to 5.2 standard deviations. The measurement yields a cross section of 13.8(-3.8)(+4.3)(stat)(-0.9)(+1.2)(syst)+/- 0.9(lum) pb, in agreement with predictions from the standard model.
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| 8. |
- Abazov, V. M., et al.
(författare)
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Search for anomalous heavy-flavor quark production in association with W bosons
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:15, s. 152002-
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Tidskriftsartikel (refereegranskat)abstract
- We search for anomalous production of heavy-flavor quark jets in association with W bosons at the Fermilab Tevatron p(p) over bar Collider in final states in which the heavy-flavor quark content is enhanced by requiring at least one tagged jet in an event. Jets are tagged using one algorithm based on semileptonic decays of b/c hadrons, and another on their lifetimes. We compare e+jets (164 pb(-1)) and mu+jets (145 pb(-1)) channels collected with the D0 detector at root s = 1.96 TeV to expectations from the standard model and set upper limits on anomalous production of such events.
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| 9. |
- Abazov, V. M., et al.
(författare)
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Search for first-generation scalar leptoquarks in p(p)over-bar collisions at root s=1.96 TeV
- 2005
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Ingår i: Physical Review D. Particles and fields. - 0556-2821 .- 1089-4918. ; 71:7, s. 071104-
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Tidskriftsartikel (refereegranskat)abstract
- We report on a search for pair production of first-generation scalar leptoquarks (LQ) in p (p) over bar collisions at root s=1.96 TeV using an integrated luminosity of 252 pb(-1) collected at the Fermilab Tevatron collider by the D0 detector. We observe no evidence for LQ production in the topologies arising from LQ(LQ) over bar -> eqeq and LQ(LQ) over bar -> eq nu q, and derive 95% C.L. lower limits on the LQ mass as a function of beta, where beta is the branching fraction for LQ -> eq. The limits are 241 and 218 GeV/c(2) for beta=1 and 0.5, respectively. These results are combined with those obtained by D0 at root s=1.8 TeV, which increases these LQ mass limits to 256 and 234 GeV/c(2).
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| 10. |
- Abazov, V. M., et al.
(författare)
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Search for the flavour-changing neutral current B-s(0)->mu+mu- in p(p)over-bar collisions at root s=1.96 TeV with the D0 dectector
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 94:7, s. 071802-
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of a search for the flavor-changing neutral current decay B-s(0)-->mu(+)mu(-) using a data set with integrated luminosity of 240 pb(-1) of p (p) over bar collisions at roots=1.96 TeV collected with the D0 detector in run II of the Fermilab Tevatron collider. We find the upper limit on the branching fraction to be B(B-s(0)-->mu(+)mu(-))less than or equal to5.0x10(-7) at the 95% C.L. assuming no contributions from the decay B-d(0)-->mu(+)mu(-) in the signal region. This limit is the most stringent upper bound on the branching fraction B-s(0)-->mu(+)mu(-) to date.
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