64 research outputs found
Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron
The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is . The combined inclusive and differential asymmetries are consistent with recent standard model predictions
Inclusive Production of the State in Collisions at D0
We present a study of the inclusive production of the with the decay to the final state in hadronic collisions. Based on of collision data collected by the D0 experiment at the Fermilab Tevatron collider, we report the first evidence for the prompt production of and find the fraction of events originating from hadrons to be . The ratio of the non-prompt production rate to the yield in the same channel is . The values of the mass ~MeV and width ~MeV are consistent with previous measurements. 8 pages, 2 figue
Search for Violation of and Lorentz invariance in meson oscillations
We present the first search for CPT-violating effects in the mixing of mesons using the full Run II data set with an integrated luminosity of 10.4 fb of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPT- and Lorentz-invariance violating coupling coefficients. We find 95\% confidence intervals of GeV and GeV
Measurement of the lifetime in the flavor-specific decay channel
We present an updated measurement of the lifetime from the D0 collaboration using the semileptonic decays , with and (and the charge conjugate process). This measurement uses the full Tevatron Run II sample of proton-antiproton collisions at ~TeV, comprising an integrated luminosity of 10.4~fb. We find a flavor-specific lifetime . This technique is also used to determine the lifetime using the analogous decay with , yielding . Both measurements are consistent with the current world averages, and the lifetime measurement is one of the most precise to date. Taking advantage of the cancellation of systematic uncertainties, we determine the lifetime ratio
Measurement of the direct -violating parameter in the decay
We measure the direct CP-violating parameter A_CP for the decay of the charged charm meson, D+ -> K-pi+pi+ (and charge conjugate), using the full 10.4 fb-1 sample of ppbar collisions at sqrt(s) = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron collider. We extract the raw reconstructed charge asymmetry by fitting the invariant mass distributions for the sum and difference of charge-specific samples. This quantity is then corrected for detector-related asymmetries using data-driven methods and for possible physics asymmetries (from B -> D processes) using input from Monte Carlo simulation. We measure A_CP = [-0.16 +- 0.15 (stat.) +- 0.09 (syst.)]%, which is consistent with zero, as expected from the standard model prediction of CP conservation, and is the most precise measurement of this quantity to dateWe measure the direct CP-violating parameter ACP for the decay of the charged charm meson, D+→K-π+π+ (and charge conjugate), using the full 10.4 fb-1 sample of pp¯ collisions at s=1.96 TeV collected by the D0 detector at the Fermilab Tevatron collider. We extract the raw reconstructed charge asymmetry by fitting the invariant mass distributions for the sum and difference of charge-specific samples. This quantity is then corrected for detector-related asymmetries using data-driven methods and for possible physics asymmetries (from B→D processes) using input from Monte Carlo simulation. We measure ACP=[-0.16±0.15(stat)±0.09(syst)]%, which is consistent with zero, as expected from the standard model prediction of CP conservation, and is the most precise measurement of this quantity to date.We measure the direct CP-violating parameter A_CP for the decay of the charged charm meson, D+ -> K-pi+pi+ (and charge conjugate), using the full 10.4 fb-1 sample of ppbar collisions at sqrt(s) = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron collider. We extract the raw reconstructed charge asymmetry by fitting the invariant mass distributions for the sum and difference of charge-specific samples. This quantity is then corrected for detector-related asymmetries using data-driven methods and for possible physics asymmetries (from B -> D processes) using input from Monte Carlo simulation. We measure A_CP = [-0.16 +- 0.15 (stat.) +- 0.09 (syst.)]%, which is consistent with zero, as expected from the standard model prediction of CP conservation, and is the most precise measurement of this quantity to dat
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