Related papers: Top-Quark Forward-Backward Symmetry
A sizeable difference in the differential production cross section of top and antitop quarks, respectively, is predicted for hadronically produced heavy quarks. It is of order $\alpha_s$ and arises from the interference between charge odd…
CDF has observed a top forward-backward asymmetry discrepant with the Standard Model prediction at 3.4 \sigma. We analyze models that could generate the asymmetry, including flavor-violating W's, horizontal Z'_Hs, triplet and sextet…
Recent CDF and D0 measurements of the top quark forward-backward asymmetry at the Tevatron present deviations between 1-sigma and 2-sigma from QCD predictions and a cut M_inv > 450 GeV on the events increases this deviation to 3.4 sigma in…
A sizable charge asymmetry in top quark pair production has been observed at the Tevatron. The experimental results seem to exceed systematically the Standard Model theory predictions by a significant amount and have triggered a large…
We perform a model independent analysis on $q \bar{q} \rightarrow t \bar{t}$ using an effective lagrangian with dim-6 four-quark operators, and derive necessary conditions on new physics that are consistent with the $t\bar{t}$ production…
We present the first measurement of the integrated forward-backward charge asymmetry in top-antitop quark pair (ttbar) production in proton-antiproton collisions in the lepton plus jets final state. Using a b-jet tagging algorithm and…
We propose two new observables to measure the charge asymmetry in hadronic top-quark pair production in association with a hard jet. The incline asymmetry, based on the inclination between the planes of initial- and final-state momenta,…
An influence of the anomalous Wtb coupling on forward-backward asymmetry of top quark pair production at the Tevatron is investigated taking into account decays of the top quarks to 6 fermion final states containing one charged lepton. To…
We determine the dominant missing Standard Model (SM) contribution to the top quark pair forward-backward asymmetry at the Tevatron. Contrary to past expectations, we find a large, around 27%, shift relative to the well-known value of the…
In theories of Partial Compositeness the top quark is a mixture of a composite and an elementary state, and as a consequence its interactions with gauge bosons are expected to deviate from those of a point-like object. At sufficiently large…
We study the phenomenology of same sign top pair production at the LHC in a model-independent way. The complete set of dimension six operators involving two top (or anti-top) quarks is introduced and the connection with all possible t- or…
We analyse a simple Standard Model (SM) extension with only two new light fields: a scalar partner of the top (stop) (with mass above m_t) and a light neutral fermion chi^0 (with mass of a few GeV), coupled to SM quarks via a Yukawa…
We consider Z' and W' models recently proposed to explain the top forward-backward asymmetry at the Tevatron. We present the next-to-leading order QCD corrections to associated production of such vector bosons together with top quarks at…
Fermion mixing is conveniently described using the effective Lagrangian formalism. We apply this approach to study top mixing in models with an infinite tower of Kaluza-Klein fermion excitations. In the Randall-Sundrum background with a…
The exchange of a light $t$-channel flavor-changing gauge boson, $\Vp$, with mass $\sim m_{top}$ remains a leading explanation for the anomalous forward backward asymmetry in top quark production at the Tevatron. Unlike other ideas,…
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,…
The scalar partners of top and bottom quarks are expected to be the lightest squarks in supersymmetric theories, with potentially large cross sections at hadron colliders. We present predictions for the production of top and bottom squarks…
The forward-backward asymmetry in e+ e- annihilation into a quark-antiquark pair is considered in the double-logarithmic approximation at energies much higher than the masses of the weak bosons. It is shown that after accounting to all…
I calculate the top quark forward-backward asymmetry at the Tevatron in both the laboratory frame and the $t{\bar t}$ rest frame. I show that soft-gluon corrections are the dominant contribution to the asymmetry and closely approximate…
We consider how the measurement of top polarization at the Tevatron can be used to characterise and discriminate among different new physics models that have been suggested to explain the anomalous top forward-backward asymmetry reported at…