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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
E Aguilo,
M Ahsan,
G D Alexeev,
G Alkhazov, [......],
C Zeitnitz,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic,
V Zutshi,
E G Zverev
[show abstract]
[hide abstract]
ABSTRACT: Anomalous Wtb couplings modify the angular correlations of the top-quark decay products and change the single top-quark production cross section. We present limits on anomalous top-quark couplings by combining information from W boson helicity measurements in top-quark decays and anomalous coupling searches in the single top-quark final state. We set limits on right-handed vector couplings as well as left-handed and right-handed tensor couplings based on about 1 fb(-1) of data collected by the D0 experiment.
Physical Review Letters 04/2009; 102(9):092002. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
E Aguilo,
M Ahsan,
G D Alexeev,
G Alkhazov, [......],
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
A Zieminski,
L Zivkovic,
V Zutshi,
E G Zverev
[show abstract]
[hide abstract]
ABSTRACT: We measure the mass of the top quark using top-quark pair candidate events in the lepton+jets channel from data corresponding to 1 fb;{-1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider. We use a likelihood technique that reduces the jet energy scale uncertainty by combining an in situ jet energy calibration with the independent constraint on the jet energy scale (JES) from the calibration derived using photon+jets and dijet samples. We find the mass of the top quark to be 171.5+/-1.8(stat.+JES)+/-1.1(syst.) GeV.
Physical Review Letters 11/2008; 101(18):182001. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
E Aguilo,
S H Ahn,
M Ahsan,
G D Alexeev, [......],
C Zeitnitz,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
A Zieminski,
L Zivkovic,
V Zutshi,
E G Zverev
[show abstract]
[hide abstract]
ABSTRACT: We present a study of the polarization of the Upsilon(1S) and Upsilon(2S) states using a 1.3 fb;{-1} data sample collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron Collider. We measure the polarization parameter alpha=(sigma_{T}-2sigma_{L})/(sigma_{T}+2sigma_{L}), where sigma_{T} and sigma_{L} are the transversely and longitudinally polarized components of the production cross section, as a function of the transverse momentum (p_{T};{Upsilon}) for the Upsilon(1S) and Upsilon(2S). Significant p_{T};{Upsilon}-dependent longitudinal polarization is observed for the Upsilon(1S). A comparison with theoretical models is presented.
Physical Review Letters 11/2008; 101(18):182004. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
E Aguilo,
M Ahsan,
G D Alexeev,
G Alkhazov, [......],
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
A Zieminski,
L Zivkovic,
V Zutshi,
E G Zverev
[show abstract]
[hide abstract]
ABSTRACT: We present an observation for ZZ-->l+l-l'+l'- (l, l'=e or mu) production in p[over]p collisions at a center-of-mass energy of sqrt[s]=1.96 TeV. Using 1.7 fb(-1) of data collected by the D0 experiment at the Fermilab Tevatron Collider, we observe three candidate events with an expected background of 0.14(+0.03)_(-0.02) events. The significance of this observation is 5.3 standard deviations. The combination of D0 results in this channel, as well as in ZZ-->l+l- nu[over]nu, yields a significance of 5.7 standard deviations and a combined cross section of sigma(ZZ)=1.60+/-0.63(stat)+0.16_-0.17(syst) pb.
Physical Review Letters 10/2008; 101(17):171803. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
E Aguilo,
S H Ahn,
M Ahsan,
G D Alexeev, [......],
C Zeitnitz,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
A Zieminski,
L Zivkovic,
V Zutshi,
E G Zverev
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the production of neutral Higgs bosons varphi decaying into tau+tau - final states in pp over collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of approximately 1 fb(-1), were collected by the D0 experiment at the Fermilab Tevatron Collider. Limits on the production cross section times branching ratio are set. The results are interpreted in the minimal supersymmetric standard model yielding limits that are the most stringent to date at hadron colliders.
Physical Review Letters 09/2008; 101(7):071804. · 7.37 Impact Factor
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M. Maggiora, V. Abazov,
G. Alexeev,
M. Alexeev,
A. Amoroso,
N. Angelov,
S. Baginyan,
F. Balestra,
V. A. Baranov,
Yu. Batusov, [......],
V. Tchalyshev,
F. Tessarotto,
E. Tomasi-Gustafsson,
F. Tosello,
E. P. Velicheva,
L. Venturelli,
L. Vertogradov,
M. Virius,
G. Zosi,
N. Zurlo
[show abstract]
[hide abstract]
ABSTRACT: New possibilities arising from the availability at GSI of antiproton beams, possibly polarised, are discussed. The investigation
of the nucleon structure can be boosted by accessing in Drell-Yan processes experimental asymmetries related to cross-sections
in which the parton distribution functions (PDF) only appear, without any contribution from fragmentation functions; such
processes are not affected by the chiral suppression of the transversity functionh
1(x). Spin asymmetries in hyperon production and Single Spin Asymmetries are discussed as well, together with further items like
electric and magnetic nucleonic form factors and open charm production. Counting rates estimations are provided for each physical
case. The sketch of a possible experimental apparatus is proposed.
Czechoslovak Journal of Physics 12/2004; 55:A75-A92. · 0.42 Impact Factor
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T. Zhao,
H.J. Lubatti,
D. Denisov,
R. Rucinski, V. Abazov,
V. Malyshev,
E. Komissarov,
A. Kalinin,
G. Alexeev,
B. Sabirov,
Y. Yatsunenko
[show abstract]
[hide abstract]
ABSTRACT: The design of the new D0 forward angle muon tracking detector and its gas system are described in this paper. The new D0 forward muon tracking detector is based on a minidrift tube technology. The minidrift tubes are operated in proportional mode using a fast nonflammable gas mixture. The basic operational characteristics of this gas mixture and the effects of impurities are presented. Special requirements of the gas system that lead to our design choices are discussed. The gas distribution, recirculation, control, and monitoring system are described.
IEEE Transactions on Nuclear Science 07/2002; · 1.45 Impact Factor
