Related papers: Constraints on generalized non-standard $tbW$ coup…
Focusing attention on top-quark pair production and its decay processes at the LHC, non-standard top-quark couplings are studied based on the effective Lagrangian constructed with SU(3)X SU(2)X U(1) invariant dimension-6 operators. The…
We reconsider the bounds on non-standard neutrino interactions with matter which can be derived by constraining the four-charged-lepton operators induced at the loop level. We find that these bounds are model dependent. Naturalness…
We present the sensitivity limits on the coefficients of a dimension-6 effective operators that parametrizes the possible effects of new physics beyond the Standard Model. Our results are based on the study of the processes $e^+ e^- \to W^+…
The process e+e- --> W+W- provides a valuable laboratory to test the Standard Model (SM) and to search for new physics. The most general helicity amplitudes for this process require the introduction of nine form-factors which we calculate…
Anomalous interactions involving the top quark contribute to some of the most difficult observables to directly access experimentally. They can give however a sizeable correction to very precisely measured observables at the loop level.…
We analyze constraints on the anomalous $Wtb$ couplings from $B$-physics experiments, performing a correlated analysis and allowing all anomalous couplings to differ simultaneously from their Standard-Model (SM) values. The $B$-physics…
The quartic gauge boson couplings that identify the strengths of the gauge boson self-interactions are exactly determined by the non-Abelian gauge nature of the Standard Model. The examination of these couplings at $ep$ collisions with high…
We discuss electroweak precision constraints on dimension-6 operators in the effective theory beyond the standard model. We identify the combinations of these operators that are constrained by the pole observables (the W and Z masses and…
We make a complete one loop calculation of the $tbW$ couplings in the Two Higgs Doublet Model. We evaluate both the anomalous couplings $g_L$ and $g_R$ as well as left handed and right handed component of $tbW$. The computation is done in…
We study in the effective Lagrangian approach the possibility of probing anomalous top quark charged current couplings in the single top production at a high energy e\gamma collider. We analyzed all possible dimension-six CP-conserving…
We investigate new physics effects on the Wtb effective couplings in a model-independent manner. The new physics effects are summarized as four independent couplings $f_1^L$, $f_1^R$, $f_2^L$ and $f_2^R$. Using single-top-quark productions…
The Lee-Wick Standard Model is a highly constrained model which solves the gauge hierarchy problem at the expense of including states with negative norm. It appears to be macroscopically causal and consistent. This model is extended by…
Effective Lagrangians can be used to parametrize the effects of physics beyond the standard model. Assuming the complete theory is a gauge theory, we determine which effective operators may be generated at tree level, and which are only…
The triple gauge couplings are completely defined by the non-Abelian gauge nature of the Standard Model, precision measurements of these couplings at the present and future colliders in this way provide a substantial opportunity to test the…
Using effective-lagrangian techniques we perform a systematic survey of the lowest-dimension effective interactions through which heavy physics might manifest itself in present experiments. We do not restrict ourselves to special classes of…
We study extensions of the Standard Model with general new vector bosons. The full Standard Model gauge symmetry is used to classify the extra vectors and constrain their couplings. We derive the corresponding effective Lagrangian, valid at…
$W$ boson pair production processes at $e^+e^-$ and $pp$ colliders have been conventionally interpreted as measurements of $WWZ$ and $WW\gamma$ triple gauge couplings (TGCs). Such interpretation is based on the assumption that new physics…
We present a study of anomalous electroweak gauge-boson couplings which can be measured in e+e- and gamma gamma collisions at a future linear collider like ILC. We consider the gauge-boson sector of a locally SU(2) x U(1) invariant…
We present a physical parameterization of the leading effects beyond the SM (BSM), that give us, at present, the best way to constrain heavy new-physics at low-energies. We call these effects that constrain all possible interactions at the…
Analyses which use loop calculations to put constraints on anomalous trilinear gauge boson couplings (TGC's) often give bounds which are much too stringent. The reason has nothing to do with gauge invariance, in contrast to the recent…