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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 415 records · Page 23
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DOE OSTI2012

Observation of a narrow mass state decaying into Υ(1S)+γ in pp̄ collisions at √s=1.96 TeV

Using data corresponding to an integrated luminosity of 1.3 fb⁻¹, we observe a narrow mass state decaying into Υ(1S)+γ, where the Υ(1S) meson is detected by its decay into a pair of oppositely charged muons, and the photon is identified through its conversion into an electron-positron pair. The significance of this observation is 5.6 standard deviations. The mass of the state is centered at 10.551±0.014(stat)±0.017(syst) GeV/c², which is consistent with that of the state recently observed by the ATLAS Collaboration.

Abazov, V. M.↗
DOE OSTI2012

Search for WH associated production in pp̄ collisions at √s=1.96 TeV

This report describes a search for associated production of W and Higgs bosons based on data corresponding to an integrated luminosity of L≈5.3 fb⁻¹ collected with the D0 detector at the Fermilab Tevatron pp̄ Collider. Events containing a W→lν candidate (with l corresponding to e or μ) are selected in association with two or three reconstructed jets. One or two of the jets are required to be consistent with having evolved from a b quark. A multivariate discriminant technique is used to improve the separation of signal and backgrounds. Expected and observed upper limits are obtained for the product of the WH production cross section and branching ratios and reported in terms of ratios relative to the prediction of the standard model as a function of the mass of the Higgs boson (M H ). The observed and expected 95% C.L. upper limits obtained for an assumed M H =115 GeV are, respectively, factors of 4.5 and 4.8 larger than the value predicted by the standard model.

Abazov, V. M.↗
DOE OSTI2012

Search for Higgs boson production in oppositely charged dilepton and missing energy events in pp̄ collisions at √s=1.96 TeV

We present a search for the standard model Higgs boson using events with two oppositely charged leptons and large missing transverse energy as expected in H→WW decays. The events are selected from data corresponding to 8.6 fb⁻¹ of integrated luminosity in pp̄ collisions at √s=1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. No significant excess above the standard model background expectation in the Higgs boson mass range this search is sensitive to is observed, and upper limits on the Higgs boson production cross section are derived.

Abazov, V. M.↗
DOE OSTI2016

$B^{0}_{s}$ lifetime measurement in the CP-odd decay channel $B^{0}_{s} \to J/\psi f_{0}(980)$

The lifetime of the Bs0 meson is measured in the decay channel Bs0→J/ψπ+π- with 880≤Mπ+π-≤1080 MeV/c2, which is mainly a CP-odd state and dominated by the f0(980) resonance. In 10.4 fb-1 of data collected with the D0 detector in Run II of the Tevatron, the lifetime of the Bs0 meson is measured to be τ(Bs0)=1.70±0.14(stat)±0.05(syst) ps. Neglecting CP violation in Bs0/B¯s0 mixing, the measurement can be translated into the width of the heavy mass eigenstate of the Bs0, ΓH=0.59±0.05(stat)±0.02(syst) ps-1.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the Inclusive $t\bar{t}$ Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV and Determination of the Top Quark Pole Mass

The inclusive cross section of top quark-antiquark pairs produced in pp¯ collisions at s=1.96 TeV is measured in the lepton+jets and dilepton decay channels. 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. Employing multivariate analysis techniques we measure the cross section in the two decay channels and we perform a combined cross section measurement. For a top quark mass of 172.5 GeV, we measure a combined inclusive top quark-antiquark pair production cross section of σtt¯=7.26±0.13(stat)-0.50+0.57(syst) pb which is consistent with standard model predictions. We also perform a likelihood fit to the measured and predicted top quark mass dependence of the inclusive cross section, which yields a measurement of the pole mass of the top quark. The extracted value is mt=172.8±1.1(theo)-3.1+3.3(exp) GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Measurement of top quark polarization in t t ¯ lepton + jets final states

We present a measurement of top quark polarization in t ¯ t pair production in p ¯ p collisions at √ s = 1.96 TeV using data corresponding to 9.7 fb -1 of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the t ¯ t production plane. This is the first measurement of top quark polarization at the Tevatron using lepton + jet final states and the first measurement of the transverse polarization in t ¯ t production. The observed distributions are consistent with standard model predictions of nearly no polarization.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Measurement of the direct CP violating charge asymmetry in $B^\pm \rightarrow \mu^\pm \nu_\mu D^{0}$ decays

We present the first measurement of the CP violating charge asymmetry in B±→μ±νμD0 decays using the full Run II integrated luminosity of 10.4 fb-1 in proton-antiproton collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure a difference in the yield of B- and B+ mesons in these decays by fitting the reconstructed invariant mass distributions. This results in an asymmetry of AμD0=[-0.14±0.20]%, which is consistent with standard model predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Combination of D0 measurements of the top quark mass

We present a combination of measurements of the top quark mass by the D0 experiment in the lepton+jets and dilepton channels. We use all the data collected in Run I (1992–1996) at s=1.8 TeV and Run II (2001–2011) at s=1.96 TeV of the Tevatron pp¯ collider, corresponding to integrated luminosities of 0.1 fb-1 and 9.7 fb-1, respectively. The combined result is: mt=174.95±0.40(stat)±0.64(syst) GeV=174.95±0.75 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗