Related papers: New and Standard Physics contributions to anomalou…
We study the one loop new physics effects to the CP even triple neutral gauge boson vertices $\gamma^\star \gamma Z$, $\gamma^\star Z Z$, $Z^\star Z \gamma$ and $Z^\star Z Z$ in the context of Little Higgs models. We compute the…
The possible form of New Physics (NP) interactions affecting the ZZZ, $ZZ \gamma$ and $Z\gamma \gamma$ vertices, is critically examined. Their signatures and the possibilities to study them, through ZZ and $Z\gamma$ production, at the…
We compute the one loop new physics effects to the CP even triple neutral gauge boson vertices $\gamma^\star \gamma Z$, $\gamma^\star Z \,Z$, $Z^\star \,Z\,\gamma$ and $Z^\star\,Z\,Z$ in the context of Little Higgs models. In addition, we…
We establish the general off-shell structure of the three neutral gauge boson self-couplings V1*V2*V3*, with applications to the Z*Z*Z*, Z*Z*gamma*, gamma*gamma*Z* cases. New coupling forms appear which do not exist when two gauge bosons…
We discuss possible New Physics (NP) effects on the processes $\gamma\gamma \to W^+W^-$, $ZZ$, $Z\gamma$, $\gamma\gamma$, $HH$ which are observable in $\gamma\gamma$ collisions. Such collisions may be achieved through laser backscattering…
In its second phase, LEP has allowed to study four fermion processes never observed before. Results are presented on the charged triple gauge boson couplings (TGC) from the W-pair, Single W and Single gamma production. The anomalous quartic…
The standard model (SM) one-loop contributions to the most general $H^*Z^*Z^*$ coupling are obtained via the background field method in terms of Passarino-Veltman scalar functions, from which the contributions to the $H^*ZZ$ and $HZZ^*$…
We analyze LEP and SLC data from the 1995 Winter Conferences for signals of new physics. We compare the data with the Standard Model (SM) as well as a number of test hypotheses concerning the nature of new physics: (i) nonstandard Zbb…
The non-Abelian gauge structure of the Standard Model implies the presence of the multi-boson self-interactions. Precise measurements in experimental and theoretical studies of these interactions allow not only testing the nature of the…
One-loop corrections to the self-coupling constant of the lightest CP-even Higgs boson are studied in the two Higgs doublet model. After renormalization is performed, quartic contributions of heavy particle's mass can appear in the…
We study the flavor-changing neutral current contributions to the trilinear neutral gauge boson couplings $Z\gamma V^\ast$ ($V=Z$, $\gamma$) at the one-loop level. Only the $CP$-conserving form factor $h_3^Z$ is induced, with the relevant…
We show that single Higgs production in $\gamma\gamma$ collisions through laser backscattering provides the best way to look for New Physics (NP) effects inducing anomalous Higgs couplings. Our analysis is based on the four $dim=6$…
It is possible to place constraints on non-Standard-Model gauge-boson self-couplings and other new physics by studying their one-loop contributions to precisely measured observables. We extend previous analyses which constrain such…
Non-Abelian structure of the Standard Model predicts the self-interactions of gauge bosons triple gauge couplings (TGC) and quartic gauge couplings (QGC). On the other hand, it is also important to determine the deviations from Standard…
It has been shown recently that the triple neutral gauge boson couplings are not uniquely determined in noncommutative extension of the Standard Model (NCSM). Depending on specific schemes used, the couplings are different and may even be…
We present a set of studies concerning the description of New Physics (NP) effects caracterized by a scale much higher than the electroweak scale. We show that both present experimental results and several types of theretical considerations…
A minimal extension of the standard model includes extra quarks with charges 2/3 and/or -1/3, whose left-handed and right-handed components are both SU(2) singlets. This model predicts new interactions of flavor-changing neutral current at…
We investigate the CP violating form factor of the ZZZ$ and $ZZ\gamma$ vertices in the pair production of $Z^0$ bosons. Useful observables in azimuthal distributions are constructed to probe $CP$ nonconservation which may originate from…
We evaluate one-loop diagrams in the unitary gauge that contribute to flavor-changing neutral current (FCNC) transitions involving two and four fermions. Specifically, we deal with penguin and box diagrams arising within the standard model…
The one-loop contributions to the trilinear neutral gauge boson couplings $ZZV^\ast$ ($V=\gamma,Z,Z'$), parametrized in terms of one $CP$-conserving $f_5^{V}$ and one $CP$-violating $f_4^{V}$ form factors, are calculated in models with…