Related papers: Four-Fermi Effective Operators at e^+ e^- ---> \ba…
We compute the next-to-next-to-leading order (NNLO) QCD correction to the total cross-section for the reaction gg \to t\bar t + X. Together with the partonic channels we computed previously, the result derived in this letter completes the…
The next-to-next-to-leading order (NNLO) QCD corrections to top quark threshold pair production in gamma-gamma collisions are computed. The NNLO effects turn out to be significant. Threshold cross sections in gamma-gamma and e+e- collisions…
We have constructed a Monte Carlo generator for lowest-order predictions for the processes gamma gamma -> 4f and gamma gamma -> 4f+gamma in the Standard Model and extensions thereof by an effective gamma gamma Higgs coupling as well as…
We present the complete calculations of the forward-backward asymmetry ($A_{\rm FB}$) and the total cross section of top quark pair production induced by dimension-six four quark operators at the Tevatron up to…
We present one-loop matching coefficients between continuum and lattice QCD for the heavy-light four-fermion operators relevant for neutral B meson mixing both within and beyond the Standard Model. For the lattice theory we use…
We perform a global analysis of the sensitivity of LEP2 and e^+e^- colliders with a c.m. energy in the range 500 - 2000 GeV to new flavor-changing single top quark production in the effective Lagrangian approach. The processes considered…
Precision measurements of high energy top quarks at the LHC constitute a powerful probe of new physics. We study the effect of four fermion operators involving two tops and two light quarks on the high energy tail of the $t\bar t$ invariant…
This paper is devoted to the Standard Model cross-sections for the production of single top, top quark in pairs, triple-top quarks, and four top-quarks at three different centre of mass-energies e.g., $\sqrt{s}=$7, 10 and 14 TeV at existing…
If the minimal supersymmetric standard model at scales of around 1 TeV is realized in nature, the total top-squark pair production cross section should be measurable at the CERN Large Hadron Collider. In this work we present precise…
The dimension-four genuine anomalous quartic couplings are studied in processes of six-fermion production via e+e- collisions. Complete tree-level electroweak calculations are performed including initial-state-radiation and beamstrahlung.…
Recently it was shown that, in the framework of superstring inspired $\E$ models, the presence of generation dependent discrete symmetries allows us to construct a phenomenologically viable class of models in which the three generations of…
We compute the total cross section for $t\bar{t}t\bar{t}$ production at next-to-leading logarithmic (NLL$^{\prime}$) accuracy. This is the first time resummation is performed for a hadron-collider process with four colored particles in the…
Many theories, from Supersymmetry to models of Strong Electroweak Symmetry Breaking, look at the production of four top quarks as an interesting channel to evidentiate signals of new physics beyond the Standard Model. The production of…
The investigation of quartic gauge couplings provides a crucial test of the Standard Model and serves as a potential window into new physics at higher energy scales. Within the framework of Effective Field Theory, deviations from the SM can…
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…
Top interactions beyond the Standard Model can be conveniently described in the framework of gauge-invariant effective operators. We briefly review the general form of the fermion-fermion-gauge boson and fermion-fermion-Higgs interactions…
We consider Non-Standard neutrino Interactions (NSI), described by four-fermion operators of the form $(\bar{\nu}_{\alpha} \gamma {\nu}_{\beta}) (\bar{f} \gamma f)$, where $f$ is an electron or first generation quark. We assume these…
In the fermion content and gauge symmetry of the standard model (SM), we study the four-fermion operators in the torsion-free Einstein-Cartan theory. The collider signatures of irrelevant operators are suppressed by the high-energy cutoff…
The energy spectrum of the lepton(s) in e^+e^- --> tt-bar --> l^{+-} ...../l^+l^-..... at next linear colliders (NLC) is studied for arbitrary longitudinal beam polarizations as a possible test of new physics in top-quark couplings. The…
In the SM gauge symmetries and fermion content of neutrinos, charged leptons and quarks, we study the effective four-fermion operators of Einstein-Cartan type and their contributions to the Schwinger-Dyson equations of fermion self-energy…