Publications
708 results found
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the Effective Weak Mixing Angle in pp¯→Z/γ∗→e+e− Events, Physical Review Letters, Vol: 115, ISSN: 1079-7114
Abe K, Adam J, Aihara H, et al., 2015, Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 pi(0) detector, Physical Review D, Vol: 91, ISSN: 1550-7998
This paper presents a measurement of the charged current interaction rate of the electron neutrino beam component of the beam above 1.5 GeV using the large fiducial mass of the T2K π0 detector. The predominant portion of the νe flux (∼85%) at these energies comes from kaon decays. The measured ratio of the observed beam interaction rate to the predicted rate in the detector with water targets filled is 0.89±0.08(stat)±0.11(sys), and with the water targets emptied is 0.90±0.09(stat)±0.13 (sys). The ratio obtained for the interactions on water only from an event subtraction method is 0.87±0.33(stat)±0.21(sys). This is the first measurement of the interaction rate of electron neutrinos on water, which is particularly of interest to experiments with water Cherenkov detectors.
Abe K, Adam J, Aihara H, et al., 2015, Measurement of the nu(mu) charged current quasielastic cross section on carbon with the T2K on-axis neutrino beam, Physical Review D, Vol: 91, ISSN: 1550-7998
We report a measurement of the νμ charged current quasielastic cross-sections on carbon in the T2K on-axis neutrino beam. The measured charged current quasielastic cross-sections on carbon at mean neutrino energies of 1.94 GeV and 0.93 GeV are (11.95±0.19(stat)+1.82−1.47(syst))×10−39 cm2/neutron, and (10.64±0.37(stat)+2.03−1.65(syst))×10−39 cm2/neutron, respectively. These results agree well with the predictions of neutrino interaction models. In addition, we investigated the effects of the nuclear model and the multi-nucleon interaction.
Abazov VM, Abbott B, Acharya BS, et al., 2015, Precision measurement of the top-quark mass in lepton+jets final states, Physical Review D, Vol: 91, ISSN: 1550-7998
We measure the mass of the top quark in lepton+jets final states using the full sample of pp¯ collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at s√=1.96 TeV, corresponding to 9.7 fb−1 of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from tt¯ production or background. The overall jet energy scale is constrained in situ by the mass of the W boson. We measure mt=174.98±0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.
Collaboration T, Abe K, Adam J, et al., 2015, Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6E20 protons on target, Physical Review D, Vol: 91, ISSN: 1550-7998
We report on measurements of neutrino oscillation using data from the T2Klong-baseline neutrino experiment collected between 2010 and 2013. In ananalysis of muon neutrino disappearance alone, we find the following estimatesand 68% confidence intervals for the two possible mass hierarchies: Normal Hierarchy: $\sin^2\theta_{23}=0.514^{+0.055}_{-0.056}$ and $\Deltam^2_{32}=(2.51\pm0.10)\times 10^{-3}$ eV$^2$/c$^4$ Inverted Hierarchy: $\sin^2\theta_{23}=0.511\pm0.055$ and $\Deltam^2_{13}=(2.48\pm0.10)\times 10^{-3}$ eV$^2$/c$^4$ The analysis accounts for multi-nucleon mechanisms in neutrino interactionswhich were found to introduce negligible bias. We describe our first analyses that combine measurements of muon neutrinodisappearance and electron neutrino appearance to estimate four oscillationparameters and the mass hierarchy. Frequentist and Bayesian intervals arepresented for combinations of these parameters, with and without includingrecent reactor measurements. At 90% confidence level and including reactormeasurements, we exclude the region: $\delta_{CP}=[0.15,0.83]\pi$ for normal hierarchy and$\delta_{CP}=[-0.08,1.09]\pi$ for inverted hierarchy. The T2K and reactor data weakly favor the normal hierarchy with a BayesFactor of 2.2. The most probable values and 68% 1D credible intervals for theother oscillation parameters, when reactor data are included, are: $\sin^2\theta_{23}=0.528^{+0.055}_{-0.038}$ and $|\Deltam^2_{32}|=(2.51\pm0.11)\times 10^{-3}$ eV$^2$/c$^4$.
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the forward-backward asymmetry in Λ<i><sub>b</sub></i><SUP>0</SUP> and (Λ)over-bar<i><sub>b</sub></i><SUP>0</SUP> baryon production in <i>p</i>(<i>p</i>)over-bar collisions at √<i>s</i>=1.96 TeV, PHYSICAL REVIEW D, Vol: 91, ISSN: 1550-7998
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- Citations: 4
Aaltonen T, Abazov VM, Abbott B, et al., 2015, Tevatron Constraints on Models of the Higgs Boson with Exotic Spin and Parity Using Decays to Bottom-Antibottom Quark Pairs, PHYSICAL REVIEW LETTERS, Vol: 114, ISSN: 0031-9007
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- Citations: 3
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the <i>W</i> plus <i>b</i>-jet and <i>W</i> plus <i>c</i>-jet differential production cross sections in <i>p</i> (<i>p</i>)over-bar collisions at √<i>s</i>=1.96 TeV, PHYSICS LETTERS B, Vol: 743, Pages: 6-14, ISSN: 0370-2693
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- Citations: 6
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the φ<sub>η</sub>* distribution of muon pairs with masses between 30 and 500 GeV in 10.4 fb<SUP>-1</SUP> of <i>p</i>(<i>p</i>)over-bar collisions, PHYSICAL REVIEW D, Vol: 91, ISSN: 1550-7998
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- Citations: 5
Abe K, Adam J, Aihara H, et al., 2015, Neutrino oscillation physics potential of the T2K experiment, Progress of Theoretical and Experimental Physics, Vol: 2015, ISSN: 2050-3911
The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle θ13 have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal sin22θ23, the octant of θ23, and the mass hierarchy, in addition to the measurements of δCP, sin2θ23, and Δm232, for various combinations of ν-mode and ν¯-mode data-taking.With an exposure of 7.8×1021protons-on-target, T2K can achieve 1σ resolution of 0.050 (0.054) on sin2θ23 and 0.040 (0.045)×10−3eV2 on Δm232 for 100% (50%) neutrino beam mode running assuming sin2θ23=0.5 and Δm232=2.4×10−3eV2. T2K will have sensitivity to the CP-violating phase δCP at 90% C.L. or better over a significant range. For example, if sin22θ23 is maximal (i.e. θ23=45∘) the range is −115∘<δCP<−60∘ for normal hierarchy and +50∘<δCP<+130∘ for inverted hierarchy. When T2K data is combined with data from the NOνA experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero δCP is substantially increased compared to if each experiment is analyzed alone.
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the ratio of inclusive cross sections σ(<i>p</i>(<i>p</i>)over-bar) → <i>Z</i>+2<i>b</i> jets/σ(<i>p</i>((<i>p</i>)over-bar) → <i>Z</i>+2 jets) in <i>p</i>((<i>p</i>)over-bar) collisions at √<i>s</i>=1.96 TeV, PHYSICAL REVIEW D, Vol: 91, ISSN: 1550-7998
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- Citations: 3
Abe K, Adam J, Aihara H, et al., 2015, Search for short baseline nu(e) disappearance with the T2K near detector, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 91, ISSN: 1550-2368
The T2K experiment has performed a search for νe disappearance due to sterile neutrinos using 5.9×1020 protons on target for a baseline of 280 m in a neutrino beam peaked at about 500 MeV. A sample of νe CC interactions in the off-axis near detector has been selected with a purity of 63% and an efficiency of 26%. The p-value for the null hypothesis is 0.085 and the excluded region at 95% C.L. is approximately sin22θee>0.3 for Δm2eff>7 eV2/c4.
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the <i>B<sub>s</sub></i><SUP>0</SUP> Lifetime in the Flavor-Specific Decay Channel <i>B<sub>s</sub></i><SUP>0</SUP>→<i>D<sub>s</sub></i><SUP>-</SUP>μ<SUP>+</SUP>ν<i>X</i>, PHYSICAL REVIEW LETTERS, Vol: 114, ISSN: 0031-9007
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- Citations: 9
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the Forward-Backward Asymmetry in the Production of B<SUP>±</SUP> Mesons in p(p)over-bar Collisions at √s=1.96 TeV, PHYSICAL REVIEW LETTERS, Vol: 114, ISSN: 0031-9007
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- Citations: 10
Abazov VM, Abbott B, Acharya BS, et al., 2015, Measurement of the electron charge asymmetry in p(p)over-bar -> W + X -> ev plus X decays in p(p)over-bar collisions at root S=1.96 TeV, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 91, ISSN: 1550-2368
We present a measurement of the electron charge asymmetry in p¯p→W+X→eν+X events at a center-of-mass energy of 1.96 TeV, using data corresponding to 9.7 fb−1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The asymmetry is measured as a function of the electron pseudorapidity and is presented in five kinematic bins based on the electron transverse energy and the missing transverse energy in the event. The measured asymmetry is compared with next-to-leading-order predictions in perturbative quantum chromodynamics and provides accurate information for the determination of parton distribution functions of the proton. This is the most precise lepton charge asymmetry measurement to date.
Abazov VM, Abbott B, Acharya BS, et al., 2014, Measurement of the direct <i>CP</i>-violating parameter A<sub>CP</sub> in the decay D<SUP>+</SUP> → K<SUP>-</SUP>π<SUP>+</SUP>π<SUP>+</SUP>, PHYSICAL REVIEW D, Vol: 90, ISSN: 1550-7998
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- Citations: 6
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the Inclusive Electron Neutrino Charged Current Cross Section on Carbon with the T2K Near Detector, PHYSICAL REVIEW LETTERS, Vol: 113, ISSN: 0031-9007
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- Citations: 40
Abazov VM, Abbott B, Acharya BS, et al., 2014, Observation and studies of double J/psi production at the Tevatron, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 90, ISSN: 1550-2368
We present the observation of doubly produced J/ψ mesons with the D0 detector at Fermilab in p¯p collisions at √s=1.96 TeV. The production cross section for both singly and doubly produced J/ψ mesons is measured using a sample with an integrated luminosity of 8.1 fb−1. For the first time, the double J/ψ production cross section is separated into contributions due to single and double parton scatterings. Using these measurements, we determine the effective cross section σeff, a parameter characterizing an effective spatial area of the parton-parton interactions and related to the parton spatial density inside the nucleon.
Abazov VM, Abbott B, Acharya BS, et al., 2014, Measurement of differential tt production cross sections in pp collisions, PHYSICAL REVIEW D, Vol: 90, ISSN: 1550-7998
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- Citations: 32
Abazov VM, Abbott B, Acharya BS, et al., 2014, Jet energy scale determination in the DO experiment, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 763, Pages: 442-475, ISSN: 0168-9002
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- Citations: 19
Abazov VM, Abbott B, Acharya BS, et al., 2014, Improved <i>b</i> quark jet identification at the D0 experiment, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 763, Pages: 290-303, ISSN: 0168-9002
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- Citations: 18
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear deexcitation gamma rays, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 90, ISSN: 1550-2368
We report the first measurement of the neutrino-oxygen neutral-current quasielastic (NCQE) cross section. It is obtained by observing nuclear deexcitation γ rays which follow neutrino-oxygen interactions at the Super-Kamiokande water Cherenkov detector. We use T2K data corresponding to 3.01×1020 protons on target. By selecting only events during the T2K beam window and with well-reconstructed vertices in the fiducial volume, the large background rate from natural radioactivity is dramatically reduced. We observe 43 events in the 4–30 MeV reconstructed energy window, compared with an expectation of 51.0, which includes an estimated 16.2 background events. The background is primarily nonquasielastic neutral-current interactions and has only 1.2 events from natural radioactivity. The flux-averaged NCQE cross section we measure is 1.55×10−38 cm2 with a 68% confidence interval of (1.22,2.20)×10−38 cm2 at a median neutrino energy of 630 MeV, compared with the theoretical prediction of 2.01×10−38 cm2.
Abazov VM, Abbott B, Acharya BS, et al., 2014, Measurement of the forward-backward asymmetry in top quark-antiquark production in p(p)over-bar collisions using the lepton plus jets channel, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 90, ISSN: 1550-2368
We present a measurement of the forward–backward asymmetry in top quark–antiquark production using the full Tevatron Run II data set collected by the D0 experiment at Fermilab. The measurement is performed in lepton+jets final states using a new kinematic fitting algorithm for events with four or more jets and a new partial reconstruction algorithm for events with only three jets. Corrected for detector acceptance and resolution effects, the asymmetry is evaluated to be AFB=(10.6±3.0)%. Results are consistent with the standard model predictions which range from 5.0% to 8.8%. We also present the dependence of the asymmetry on the invariant mass of the top quark–antiquark system and the difference in rapidities of the top quark and antiquark.
Abazov VM, Abbott B, Acharya BS, et al., 2014, Constraints on Models for the Higgs Boson with Exotic Spin and Parity in <i>VH</i> → <i>Vb</i>(<i>b</i>)over-bar Final States, PHYSICAL REVIEW LETTERS, Vol: 113, ISSN: 0031-9007
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- Citations: 7
Abazov VM, Abbott B, Acharya BS, et al., 2014, Measurement of the differential γ+2b-jet cross section and the ration σ(γ+2<i>b</i>-jets)/σ(γ plus <i>b</i>-jet) in p(p)over-bar collisions at √s=1.96 TeV, PHYSICS LETTERS B, Vol: 737, Pages: 357-365, ISSN: 0370-2693
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- Citations: 6
Abazov VM, Abbott B, Acharya BS, et al., 2014, Measurement of the forward-backward asymmetry in the distribution of leptons in <i>t</i>(<i>t</i>)over-bar events in the lepton plus jets channel, PHYSICAL REVIEW D, Vol: 90, ISSN: 1550-7998
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- Citations: 23
Abdallah J, Abreu P, Adam W, et al., 2014, Measurement of the electron structure function <i>F</i><sub>2</sub><i><SUP>e</SUP></i> at LEP energies, PHYSICS LETTERS B, Vol: 737, Pages: 39-47, ISSN: 0370-2693
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- Citations: 1
Abe K, Adam J, Aihara H, et al., 2014, Measurement of the inclusive nu(mu) charged current cross section on iron and hydrocarbon in the T2K on-axis neutrino beam, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 90, ISSN: 1550-2368
We report a measurement of the νμ inclusive charged current cross sections on iron and hydrocarbon in the Tokai-to-Kamioka (T2K) on-axis neutrino beam. The measured inclusive charged current cross sections on iron and hydrocarbon averaged over the T2K on-axis flux with a mean neutrino energy of 1.51 GeV are (1.444±0.002(stat)+0.189−0.157(syst))×10−38 cm2/nucleon and (1.379±0.009(stat)+0.178−0.147(syst))×10−38 cm2/nucleon, respectively, and their cross-section ratio is 1.047±0.007(stat)±0.035(syst). These results agree well with the predictions of the neutrino interaction model, and thus we checked the correct treatment of the nuclear effect for iron and hydrocarbon targets in the model within the measurement precisions.
Abazov VM, Abbott B, Acharya BS, et al., 2014, Measurement of the electric charge of the top quark in <i>t</i>(<i>t</i>)over-bar events, PHYSICAL REVIEW D, Vol: 90, ISSN: 1550-7998
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- Citations: 7
Abazov VM, Abbott B, Acharya BS, et al., 2014, Precision measurement of the top quark mass in lepton plus jets final states, Physical Review Letters, Vol: 113, ISSN: 0031-9007
We measure the mass of the top quark in lepton+jets final states using the full sample of p¯p collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at √s=1.96 TeV, corresponding to 9.7 fb−1 of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from t¯t production or background. The overall jet energy scale is constrained in situ by the mass of the W boson. We measure mt=174.98±0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.
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