Evidence for Zc±(3900)Z_c^{\pm}(3900) in semi-inclusive decays of bb-flavored hadrons

International audienceWe present evidence for the exotic charged charmoniumlike state Zc±(3900) decaying to J/ψπ± in semi-inclusive weak decays of b-flavored hadrons. The signal is correlated with a parent J/ψπ+π- system in the invariant-mass range 4.2–4.7 GeV that would include the exotic structure Y(4260). The study is based on 10.4  fb−1 of pp¯ collision data collected by the D0 experiment at the Fermilab Tevatron collider

Measurement of the forward-backward asymmetry in Λb0\Lambda_b^0 and Λ‾b0\overline \Lambda_b^0 baryon production in pp‾p \overline p collisions at s=1.96\sqrt s =1.96 TeV

We measure the forward-backward asymmetry in the production of $\Lambda_b^0$ and $\overline \Lambda_b^0$ baryons as a function of rapidity in $p \overline p$ collisions at $\sqrt s =1.96$ TeV using $10.4$ fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron collider. The asymmetry is determined by the preference of $\Lambda_b^0$ or $\overline \Lambda_b^0$ particles to be produced in the direction of the beam protons or antiprotons, respectively. The measured asymmetry integrated over rapidity $y$ in the range $0.1<|y|<2$ is $A=0.04 \pm 0.07 {\rm (stat)} \pm 0.02 {\rm (syst)}$

Measurement of spin correlation between top and antitop quarks produced in ppˉp\bar{p} collisions at s=1.96\sqrt{s} = 1.96 TeV

We present a measurement of the correlation between the spins of t and tbar quarks produced in proton-antiproton collisions at the Tevatron Collider at a center-of-mass energy of 1.96 TeV. We apply a matrix element technique to dilepton and single-lepton+jets final states in data accumulated with the D0 detector that correspond to an integrated luminosity of 9.7 fb$^{-1}$. The measured value of the correlation coefficient in the off-diagonal basis, $O_{off} = 0.89 \pm 0.22$ (stat + syst), is in agreement with the standard model prediction, and represents evidence for a top-antitop quark spin correlation difference from zero at a level of 4.2 standard deviations.We present a measurement of the correlation between the spins of t and t¯ quarks produced in proton–antiproton collisions at the Tevatron Collider at a center-of-mass energy of 1.96 TeV. We apply a matrix element technique to dilepton and single-lepton+jets final states in data accumulated with the D0 detector that correspond to an integrated luminosity of 9.7 fb−1 . The measured value of the correlation coefficient in the off-diagonal basis, Ooff=0.89±0.22(stat+syst) , is in agreement with the standard model prediction, and represents evidence for a top–antitop quark spin correlation difference from zero at a level of 4.2 standard deviations.We present a measurement of the correlation between the spins of t and tbar quarks produced in proton-antiproton collisions at the Tevatron Collider at a center-of-mass energy of 1.96 TeV. We apply a matrix element technique to dilepton and single-lepton+jets final states in data accumulated with the D0 detector that correspond to an integrated luminosity of 9.7 fb$^{-1}$. The measured value of the correlation coefficient in the off-diagonal basis, $O_{off} = 0.89 \pm 0.22$ (stat + syst), is in agreement with the standard model prediction, and represents evidence for a top-antitop quark spin correlation difference from zero at a level of 4.2 standard deviations

Precise measurement of the top quark mass in dilepton decays using optimized neutrino weighting

We measure the top quark mass in dilepton final states of top-antitop events in proton-antiproton collisions at sqrt(s) = 1.96 TeV, using data corresponding to an integrated luminosity of 9.7 fb^-1 at the Fermilab Tevatron Collider. The analysis features a comprehensive optimization of the neutrino weighting method to minimize the statistical uncertainties. We also improve the calibration of jet energies using the calibration determined in top-antitop to lepton+jets events, which reduces the otherwise limiting systematic uncertainty from the jet energy scale. The measured top quark mass is mt = 173.32 +/- 1.36(stat) +/- 0.85(syst) GeV

Study of the normalized transverse momentum distribution of WW bosons produced in ppˉp \bar p collisions at s\sqrt {s} = 1.96 TeV

International audienceWe present a study of the normalized transverse momentum distribution of W bosons produced in pp¯ collisions, using data corresponding to an integrated luminosity of 4.35  fb-1 collected with the D0 detector at the Fermilab Tevatron collider at s=1.96  TeV. The measurement focuses on the transverse momentum region below 15 GeV, which is of special interest for electroweak precision measurements; it relies on the same detector calibration methods which were used for the precision measurement of the W boson mass. The measured distribution is compared to different QCD predictions and a procedure is given to allow the comparison of any further theoretical models to the D0 data

Study of the X±(5568){X^\pm(5568)} state with semileptonic decays of the Bs0{B_s^0} meson

International audienceWe present a study of the X±(5568) using semileptonic decays of the Bs0 meson using the full run II integrated luminosity of 10.4  fb-1 in proton-antiproton collisions at a center of mass energy of 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. We report evidence for a narrow structure, X±(5568), in the decay sequence X±(5568)→Bs0π± where Bs0→μ∓Ds±X, Ds±→ϕπ± which is consistent with the previous measurement by the D0 Collaboration in the hadronic decay mode, X±(5568)→Bs0π± where Bs0→J/ψϕ. The mass and width of this state are measured using a combined fit of the hadronic and semileptonic data, yielding m=5566.9-3.1+3.2(stat)-1.2+0.6(syst)  MeV/c2, Γ=18.6-6.1+7.9(stat)-3.8+3.5(syst)  MeV/c2 with a significance of 6.7σ