Measurement of the forward-backward asymmetry in the distribution of leptons in $t\bar{t}$ events in the lepton$+$jets channel

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Rev.D 90 (2014) 072001, 2014.
Inspire Record 1283842 DOI 10.17182/hepdata.64673

We present measurements of the forward-backward asymmetry in the angular distribution of leptons from decays of top quarks and antiquarks produced in proton-antiproton collisions. We consider the final state containing a lepton and at least three jets. The entire sample of data collected by the D0 experiment during Run II of the Fermilab Tevatron Collider, corresponding to 9.7 inverse fb of integrated luminosity, is used. The asymmetry measured for reconstructed leptons is $A_{FB}^l = \big(2.9 \pm 2.1(stat.) ^{+1.5}_{-1.7}(syst.) \big)$%. When corrected for efficiency and resolution effects within the lepton rapidity coverage of $|y_l|<1.5$, the asymmetry is found to be $A_{FB}^l = \big(4.2 \pm 2.3(stat.) ^{+1.7}_{-2.0}(syst.) \big)$%. Combination with the asymmetry measured in the dilepton final state yields $A_{FB}^l = \big(4.2 \pm 2.0(stat.) \pm 1.4(syst.) \big)$%. We examine the dependence of $A_{FB}^l$ on the transverse momentum and rapidity of the lepton. The results are in agreement with predictions from the next-to-leading-order QCD generator \mcatnlo, which predicts an asymmetry of $A_{FB}^l = 2.0$% for $|y_l|<1.5$.

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Measurement of the photon$+b$-jet production differential cross section in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Acharya, B.S. ; et al.
Phys.Lett.B 714 (2012) 32-39, 2012.
Inspire Record 1095100 DOI 10.17182/hepdata.61739

We present measurements of the differential cross section dsigma/dpT_gamma for the inclusive production of a photon in association with a b-quark jet for photons with rapidities |y_gamma|< 1.0 and 30<pT_gamma <300 GeV, as well as for photons with 1.5<|y_gamma|< 2.5 and 30< pT_gamma <200 GeV, where pT_gamma is the photon transverse momentum. The b-quark jets are required to have pT>15 GeV and rapidity |y_jet| < 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.

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Measurement of dijet angular distributions at s**(1/2) = 1.96-TeV and searches for quark compositeness and extra spatial dimensions

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 103 (2009) 191803, 2009.
Inspire Record 824127 DOI 10.17182/hepdata.52427

We present the first measurement of dijet angular distributions in ppbar collisions at sqrt{s}=1.96TeV at the Fermilab Tevatron Collider. The measurement is based on a dataset corresponding to an integrated luminosity of up to 0.7fb-1 collected with the D0 detector. Dijet angular distributions have been measured over a range of dijet masses, from 0.25TeV to above 1.1TeV. The data are in good agreement with the predictions of perturbative QCD and are used to constrain new physics models including quark compositeness, large extra dimensions, and TeV-1 scale extra dimensions. For all models we set the most stringent direct limits to date.

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Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Lett.B 678 (2009) 45-54, 2009.
Inspire Record 815094 DOI 10.17182/hepdata.51854

We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.

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Measurement of the shape of the boson transverse momentum distribution in $p \bar{p} \to Z / \gamma^{*} \to e^+ e^- + X$ events produced at $\sqrt{s}$=1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 100 (2008) 102002, 2008.
Inspire Record 769689 DOI 10.17182/hepdata.50920

We present a measurement of the shape of the Z/gamma* boson transverse momentum (qT) distribution in ppbar -> Z/gamma* -> ee+X events at a center-of-mass energy of 1.96 TeV using 0.98 fb-1 of data collected with the D0 detector at the Fermilab Tevatron collider. The data are found to be consistent with the resummation prediction at low qT, but above the perturbative QCD calculation in the region of qT>30 GeV/c. Using events with qT<30 GeV/c, we extract the value of g2, one of the non-perturbative parameters for the resummation calculation. Data at large boson rapidity y are compared with the prediction of resummation and with alternative models that employ a resummed form factor with modifications in the small Bjorken x region of the proton wave function.

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First measurement of $\sigma$ ($p \bar{p} \to Z^{)}$ . Br ($Z \to \tau \tau^{)}$ at $\sqrt{s}$ = 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.

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Measurement of the Differential Cross-Section for the Production of an Isolated Photon with Associated Jet in $p \bar{p}$ Collisions at $\sqrt{s}$ = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Lett.B 666 (2008) 435-445, 2008.
Inspire Record 782968 DOI 10.17182/hepdata.50549

The process $p\bar{p} \to \gamma$ + jet + X is studied using 1.0 $fb^{-1}$ of data collected by the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider at a center-of-mass energy $\sqrt{s}$=1.96 TeV. Photons are reconstructed in the central rapidity region |$y^{\gamma}$|< 1.0 with transverse momenta in the range 30<$p^{\gamma}_T$<400 GeV while jets are reconstructed in either the central |$y^{jet}$|< 0.8 or forward 1.5 <|$y^{jet}$|<2.5 rapidity intervals with $p^{jet}_T$> 15 GeV. The differential cross section $d^3\sigma/dp^{\gamma}_T dy^\gamma dy^{jet}$ is measured as a function of $p^{\gamma}_T$ in four regions, differing by the relative orientations of the photon and the jet in rapidity. Ratios between the differential cross sections in each region are also presented. Next-to-leading order QCD predictions using different parameterizations of parton distribution functions and theoretical scale choices are compared to the data. The predictions do not simultaneously describe the measured normalization and Pt_gamma dependence of the cross section in any of the four measured regions.

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Measurement of inclusive differential cross sections for $\upsilon_{1S}$ production in $p \bar{p}$ collisions at $\sqrt{s}$ = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 94 (2005) 232001, 2005.
Inspire Record 676877 DOI 10.17182/hepdata.51525

We present measurements of the inclusive production cross sections of the Upsilon(1S) bottomonium state in ppbar collisions at sqrt(s) = 1.96 TeV. Using the Upsilon(1S) to mu+mu- decay mode for a data sample of 159 +- 10 pb^-1 collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Upsilon(1S) transverse momentum for three ranges of the Upsilon(1S) rapidity: 0 < |y| < 0.6, 0.6 < |y| < 1.2, and 1.2 < |y| < 1.8.

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Measurement of differential $Z / \gamma^{*}$ + jet + $X$ cross sections in $p \bar{p}$ collisions at $\sqrt{s}$ = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Lett.B 669 (2008) 278-286, 2008.
Inspire Record 792812 DOI 10.17182/hepdata.49090

We present new measurements of differential cross sections for Z/gamma*(->mumu)+jet+X production in a 1 fb-1 data sample collected with the D0 detector in proton anti-proton collisions at sqrt{s}=1.96 TeV. Results include the first measurements differential in the Z/gamma* transverse momentum and rapidity, as well as new measurements differential in the leading jet transverse momentum and rapidity. Next-to-leading order perturbative QCD predictions are compared to the measurements, and reasonable agreement is observed, except in the region of low Z/gamma* transverse momentum. Predictions from two event generators based on matrix elements and parton showers, and one pure parton shower event generator are also compared to the measurements. These show significant overall normalization differences to the data and have varied success in describing the shape of the distributions.

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Measurement of Z/gamma*+jet+X angular distributions in p anti-p collisions at s**(1/2) = 1.96.TeV

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Abolins, Maris A. ; et al.
Phys.Lett.B 682 (2010) 370-380, 2010.
Inspire Record 826756 DOI 10.17182/hepdata.52513

We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.

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