We present a measurement of the W boson mass using data corresponding to 4.3 fb{sup -1} of integrated luminosity collected with the D0 detector during Run II at the Fermilab Tevatron p{bar p} ...collider. With a sample of 1677394 W {yields} e{nu} candidate events, we measure M{sub W} = 80.367 {+-} 0.026 GeV. This result is combined with an earlier D0 result determined using an independent Run II data sample, corresponding to 1 fb{sup -1} of integrated luminosity, to yield M{sub W} = 80.375 {+-} 0.023 GeV.
We present measurements of the differential cross section dσ/dργτ for the inclusive production of a photon in association with a b -quark jet for photons with rapidities |yγ| < 1.0 and 30 < ργτ < 300 ...GeV , as well as for photons with 1.5 <|yγ| < 2.5 and 30 < ργτ < 200 GeV, where ργτ is the photon transverse momentum. The b -quark jets are required to have pT > 15 GeV and rapidity |yjet| < 1.5. 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 $p\bar{p}$ Collider at $\sqrt{s}$ =1.96 TeV. The measured cross sections are compared with next-to-leading order perturbative QCD calculations using different sets of parton distribution functions as well as to predictions based on the kT-factorization QCD approach, and those from the SHERPA and PYTHIA Monte Carlo event generators.
Here, we present a search for the pair production of scalar top quarks ($\sim\atop{t}$1), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy ...of 1.96 TeV, using data corresponding to an integrated luminosity of 7.3fb-1 collected with the D0 experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a b quark, a charged lepton, and a scalar neutrino (ν˜). We investigate final states arising from$\sim\atop{t}$1 $≂\atop{t}$1→$b\bar{b}$ μτ$\sim\atop{v}$$\sim\atop{v}$ and $\sim\atop{t}$1$≂\atop{t}$1→$b\bar{b}$ ττ$\sim\atop{v}$$\sim\atop{v}$. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the (m$\sim\atop{t}$1, m$\sim\atop{v}$) plane.
We demonstrate that spin-orbit coupling (SOC) strength for electrons near the conduction band edge in few-layer γ -InSe films can be tuned over a wide range. This tunability is the result of a ...competition between film-thickness-dependent intrinsic and electric-field-induced SOC, potentially, allowing for electrically switchable spintronic devices. Using a hybrid k ⋅ p tight-binding model, fully parametrized with the help of density functional theory computations, we quantify SOC strength for various geometries of InSe-based field-effect transistors. The theoretically computed SOC strengths are compared with the results of weak antilocalization measurements on dual-gated multilayer InSe films, interpreted in terms of Dyakonov-Perel spin relaxation due to SOC, showing a good agreement between theory and experiment.
We report results from searches for neutral Higgs bosons produced in p{bar p} collisions recorded by the D0 experiment at the Fermilab Tevatron Collider. We study the production of inclusive neutral ...Higgs boson in the {tau}{tau} final state and in association with a b quark in the b{tau}{tau} and bbb final states. These results are combined to improve the sensitivity to the production of neutral Higgs bosons in the context of the minimal supersymmetric standard model (MSSM). The data are found to be consistent with expectation from background processes. Upper limits on MSSM Higgs boson production are set for Higgs boson masses ranging from 90 to 300 GeV. We exclude tan {beta} > 20-30 for Higgs boson masses below 180 GeV. These are the most stringent constraints on MSSM Higgs boson production in p{bar p} collisions.
The numbers of “ \(\gamma + {\mathrm {jet}}\)” events suitable for the determination of the gluon distribution function fpg(x,Q2) in a proton at the LHC for various intervals of x and Q2 are ...estimated. The contributions of background events of different sources are studied and estimated in the considered intervals of x and Q2. The PYTHIA event generator was used to produce physical events for this analysis.
Combination of CDF and D0 W -Boson mass measurements Agnew, J. P.; Annovi, A.; Bandurin, D. V. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
09/2013, Letnik:
88, Številka:
5
Journal Article
Recenzirano
Odprti dostop
We summarize and combine direct measurements of the mass of the W boson in radicals = 1.96 TeV proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. ...Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to 2.2 fb super(-1) of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to 4.3 fb super(-1) of integrated luminosity. The resulting Tevatron average for the mass of the W boson is MW = 80387 + or - 16 MeV. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of MW = 80385 + or - 15 MeV.
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