Lev Dudko

Modeling of anomalous Wtb interactions in single top quark events using subsidiary fields

A method to simulate anomalous fermion-boson interactions n Wtb vertex is presented with a minimal set of simulated samples of single top quark events at th e LHC energies. In proposed method, additional subsidiary vector fields corresponding to the St andard Model gauge fields are implemented for each type of the anomalous vertex structure. The method a ll ws to simulate a manifestation of anomalous gauge couplings in two approaches used in experim ental analyses either keeping only the linear order contributions in the anomalous couplings or ke eping all contributions in numerators and denominators as appeared in matrix elements. For the proces ses with several anomalous couplings contributing simultaneously to the production and to the decay as well as to various interference terms the method allows to model correctly the dependence of kinemati c distributions on anomalous couplings. The method shows how to generate a minimum set of event sample s needed for a concrete analysis. All the single top quark production mechanisms, t-, sand associative tW-channels, are considered. The correctness of the proposed method is demonstrated.A method to simulate anomalous fermion–boson interactions in Wtb vertex is presented with a minimal set of simulated samples of single top quark events at the LHC energies. In the proposed method, additional subsidiary vector fields corresponding to the Standard Model gauge fields are implemented for each type of the anomalous vertex structure. The method allows to simulate a manifestation of anomalous gauge couplings in two approaches used in experimental analyses either keeping only the linear order contributions in the anomalous couplings or keeping all contributions in numerators and denominators as appeared in matrix elements. For the processes with several anomalous couplings contributing simultaneously to the production and to the decay as well as to various interference terms the method allows to model correctly the dependence of kinematic distributions on anomalous couplings. The method shows how to generate a minimum set of event samples needed for a concrete analysis. All the single top quark production mechanisms, t-, s- and associative tW-channels, are considered. The correctness of the proposed method is demonstrated.

Complete calculations of

We present the results of a complete tree level calculation of the processes pp(\bar p) -> Wb\bar b and Wb\bar b + jet that includes the single top signal and all irreducible backgrounds simultaneously. In order to probe the structure of the Wtb coupling with the highest possible accuracy and to look for possible deviations from standard model predictions, we identify sensitive observables and propose an optimal set of cuts which minimizes the background compared to the signal. At the LHC, the single top and the single anti-top rates are different and the corresponding asymmetry yields additional information. The analysis shows that the sensitivity for anomalous couplings will be improved at the LHC by a factor of 2--3 compared to the expectations for the first measurements at the upgraded Tevatron. Still, the bounds on anomalous couplings obtained at hadron colliders will remain 2--8 times larger than those from high energy gamma-e colliders, which will, however, not be available for some time. All basic calculations have been carried out using the computer package CompHEP. The known NLO corrections to the single top rate have been taken into account.

HIGGS BOSON PRODUCTION UNDER THE RESONANCE THRESHOLD AT LEP II

We consider the possibility of Higgs boson detection at LEP II under the resonance threshold in the framework of complete tree level approach to the calculation of the amplitude, simulating b quark fragmentation to hadrons and taking into account typical detector properties. At the energy below the 2mZ threshold Higgs boson production under the mH + mZ threshold is almost background free.We consider the possibility of Higgs boson detection at LEP II under the resonance threshold (

LIGHT AND INTERMEDIATE HIGGS BOSON SEARCH AT TEVATRON ENERGIES

\sqrt{s}<m_H+m_Z

Complete calculations of \(Wb\bar{b}\) and \(Wb\bar{b}+\) jet production at Tevatron and LHC: Probing anomalous Wtb couplings in single-top production

) in the framework of complete tree level approach to the calculation of the

Model independent top quark width measurement using a combination of resonant and non resonant cross sections.

e^+ e^- \rightarrow \nu \bar \nu b \bar b

Probing anomalous off-shell electroweak dipole moment of the top quark

amplitude, simulating b-quark fragmentation to hadrons and taking into account typical detector properties. At the energy below the

Modeling of associated tW single top production including the interference with tt¯ diagrams

2m_Z

Probing the Anomalous Wtb couplings in different schemes of tWb associated production modeling

threshold

On the top-quark width measurement using a combination of resonant and non resonant cross sections.

\sqrt{s}=