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We report on a study of the measurement techniques used to determine the leptonic forward-backward asymmetry of top anti-top quark pairs in Tevatron experiments with a proton anti-proton initial state. Recently it was shown that a fit of…

High Energy Physics - Phenomenology · Physics 2014-07-30 Ziqing Hong , Ryan Edgar , Sarah Henry , David Toback , Jonathan S. Wilson , Dante Amidei

Recent experimental results from the CDF collaboration which study the top forward-backward asymmetry have strengthened the case that new physics is playing a role in t-tbar production. Here we propose a set of measurements, built from the…

High Energy Physics - Phenomenology · Physics 2013-05-29 David Krohn , Tao Liu , Jessie Shelton , Lian-Tao Wang

We present a new measurement of the forward-backward asymmetry in ttbar production in ppbar collisions in the lepton+jets channel at D0. We measure asymmetries from two different observables and unfold the data to allow the results to be…

High Energy Physics - Experiment · Physics 2019-08-14 Douglas Orbaker

The measurement of forward-backward asymmetry in the top and anti-top quark ($t \bar{t}$) production has been recently reconfirmed by the CDF Collaboration and shows a more than $3\sigma$ deviation from the Standard Model(SM) prediction in…

High Energy Physics - Phenomenology · Physics 2011-05-13 Biplob Bhattacherjee , Sudhansu S. Biswal , Diptimoy Ghosh

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…

High Energy Physics - Experiment · Physics 2014-10-15 D0 Collaboration

Among different measured observables of top-antitop quark pairs at hadron colliders, the forward-backward asymmetry ($A_{\text{FB}}$) measured by the CDF and D0 collaborations has inconsistency with the Standard Model prediction. The…

High Energy Physics - Phenomenology · Physics 2013-02-21 Sara Khatibi , Mojtaba Mohammadi Najafabadi

We present measurements of lepton (l) angular distributions in ttbar -> W+ b W- b -> l+ nu b l- nubar bbar decays produced in ppbar collisions at a center-of-mass energy of sqrt(s)=1.96TeV, where l is an electron or muon. Using data…

High Energy Physics - Experiment · Physics 2015-03-20 D0 Collaboration

We revisit the possibility that the top quark forward-backward asymmetry arises from the on-shell production and decay of scalar top partners to top-antitop pairs with missing transverse energy. Although the asymmetry is produced by…

High Energy Physics - Phenomenology · Physics 2013-11-22 Abhishek Kumar , John N. Ng , Andrew Spray , Peter T. Winslow

We present a simultaneous measurement of the forward-backward asymmetry and the top-quark polarization in $t\bar t$ production in dilepton final states using 9.7 fb$^{-1}$ of proton-antiproton collisions at $\sqrt{s}=1.96$ TeV with the D0…

High Energy Physics - Experiment · Physics 2015-09-29 D0 Collaboration

We propose a supersymmetric explanation for the anomalously high forward backward asymmetry in top pair production measured by CDF and D0. We suppose that it is due to the t-channel exchange of a right-handed sbottom which couples to d_R…

High Energy Physics - Phenomenology · Physics 2013-05-30 B. C. Allanach , K. Sridhar

The top quark forward-backward asymmetry A_{FB}^t measured at the Tevatron is above the Standard Model prediction by more than 2-sigma deviation, which might be a harbinger for new physics. In this work we examine the contribution to…

High Energy Physics - Phenomenology · Physics 2010-04-06 Junjie Cao , Zhaoxia Heng , Lei Wu , Jin Min Yang

The anomalous forward-backward asymmetry (A_FB) in t tbar production at the Tevatron is in apparent contradiction with the t tbar charge asymmetry (A_C) measurements at the LHC, which agree well with the standard model predictions. We argue…

High Energy Physics - Phenomenology · Physics 2012-12-04 Jure Drobnak , Alexander L. Kagan , Jernej F. Kamenik , Gilad Perez , Jure Zupan

We consider the recent measurement of the top quark forward-backward asymmetry at the Fermilab Tevatron, which shows a discrepancy of slightly more than 2$\sigma$ compared to the SM prediction. We find that $t$-channel exchange of a color…

High Energy Physics - Phenomenology · Physics 2010-12-09 Jing Shu , Tim M. P. Tait , Kai Wang

We propose to measure the threshold lepton asymmetry, that is the forward-backward asymmetry of the charged lepton in ttbar events near the production threshold. At threshold top quark pairs are produced in an s-wave. Angular momentum…

High Energy Physics - Phenomenology · Physics 2013-03-14 Adam Falkowski , Gilad Perez , Martin Schmaltz

A larger than expected forward-backward asymmetry in rapidity is observed in top quark pairs produced in proton-antiproton collisions at the Tevatron. The asymmetry is seen in both the top quark distribution $A_{FB}^t$ and in the…

High Energy Physics - Phenomenology · Physics 2011-11-18 Edmond L. Berger , Qing-Hong Cao , Chuan-Ren Chen , Jiang-Hao Yu , Hao Zhang

Forward-backward asymmetries $A_{FB}^t$ and $A_{FB}^\ell$ are observed in the top quark $t$ rapidity distribution and in the rapidity distribution of charged leptons $\ell$ from top quark decay at the Tevatron proton-antiproton collider,…

High Energy Physics - Phenomenology · Physics 2013-01-23 Edmond L. Berger

We present a new measurement of the inclusive forward-backward t-tbar production asymmetry and its rapidity and mass dependence. The measurements are performed with 5.3 fb^{-1} of p-pbar collisions at \sqrt{s} = 1.96 TeV, recorded with CDF…

High Energy Physics - Experiment · Physics 2011-06-24 The CDF Collaboration , T. Aaltonen

The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large $\ttbar$ invariant masses. Measurements of this quantity are subtle…

High Energy Physics - Phenomenology · Physics 2013-05-29 JoAnne L. Hewett , Jessie Shelton , Michael Spannowsky , Tim M. P. Tait , Michihisa Takeuchi

A sizeable difference in the differential production cross section of top- compared to antitop-quark production, denoted charge asymmetry, has been observed at the Tevatron. The experimental results seem to exceed the theory predictions…

High Energy Physics - Phenomenology · Physics 2015-05-30 Johann H. Kuhn , German Rodrigo

We define a lepton-based asymmetry in semi-leptonic ttbar production at the LHC. We show that the ratio of this lepton-based asymmetry and the ttbar charge asymmetry, measured as a function of the lepton transverse momentum or the ttbar…

High Energy Physics - Phenomenology · Physics 2015-06-18 Adrian Carmona , Mikael Chala , Adam Falkowski , Sara Khatibi , Mojtaba Mohammadi Najafabadi , Gilad Perez , Jose Santiago
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