Date

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First measurement of sigma (p anti-p ---> Z) . Br (Z ---> tau tau) at s**(1/2) = 1.96- TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.D 71 (2005) 072004, 2005.
Inspire Record 666357 DOI 10.17182/hepdata.50921

We present a measurement of the cross section for $Z$ production times the branching fraction to $\tau$ leptons, $\sigma \cdot$Br$(Z\to \tau^+ \tau^-)$, in $p \bar p$ collisions at $\sqrt{s}=$1.96 TeV in the channel in which one $\tau$ decays into $\mu \nu_{\mu} \nu_{\tau}$, and the other into $\rm {hadrons} + \nu_{\tau}$ or $e \nu_e \nu_{\tau}$. The data sample corresponds to an integrated luminosity of 226 pb$^{-1}$ collected with the D{\O}detector at the Fermilab Tevatron collider. The final sample contains 2008 candidate events with an estimated background of 55%. From this we obtain $\sigma \cdot$Br$(Z \to \tau^+ \tau^-)=237 \pm 15$(stat)$\pm 18$(sys)$ \pm 15$(lum) pb, in agreement with the standard model prediction.

1 data table

Measured cross section times branching ratio.


Measurement of the WW production cross section in p anti-p collisions at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 94 (2005) 151801, 2005.
Inspire Record 1650063 DOI 10.17182/hepdata.42037

A change in estimated integrated luminosity (from 226 pb$^{-1} to 257 pb$^{-1}$ leads to a corrected value for ${\sigma (p \bar p \to Z) \cdot}$Br${(Z \to \tau \tau)}$ of $209\pm13(stat.)\pm16(syst.)\pm13(lum) pb.

1 data table

Total cross section for W boson pair production. The second systematic (DSYS) error is due to the uncertainty in the luminosity.


Measurement of dijet azimuthal decorrelations at central rapidities in p anti-p collisions at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 94 (2005) 221801, 2005.
Inspire Record 659398 DOI 10.17182/hepdata.19397

Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the D0 detector in pp-bar collisions at a center-of-mass energy sqrt(s)=1.96 TeV. The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb-1. Azimuthal correlations are stronger at larger transverse momenta. These are well-described in perturbative QCD at next-to-leading order in the strong coupling constant, except at large azimuthal differences where soft effects are significant.

4 data tables

Distribution for the maxPT jet from 75 to 100 GeV.

Distribution for the maxPT jet from 100 to 130 GeV.

Distribution for the maxPT jet from 130 to 180 GeV.

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Observation of the top quark

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 74 (1995) 2632-2637, 1995.
Inspire Record 393099 DOI 10.17182/hepdata.42452

The DO collaboration reports on a search for the Standard Model top quark in pbar-p collisions at Sqrt(s)=1.8TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50pb-1. We have searched for t-tbar production in the dilepton and single-lepton decay channels, with and without tagging of b-quark jets. We observed 17 events with an expected background of 3.8+/-0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2.0E-6 (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199~+19_21 (stat.)+/- 22 (syst.)GeV/c**2 and its production cross section to be 6.4 +/- 2.2 pb.

1 data table

Cross section refers to top quark mass equal 199. (+19, -21, +- 22) GeV.