Related papers: Some Remarks on the Matching Conditions
We investigate the $\Delta S = 1,2$ effective weak chiral Lagrangian within the framework of the chiral quark model. Starting from the effective four-quark operators, we derive the effective weak chiral action by integrating out the…
We consider a generic composite Higgs model based on the coset SO(5)/SO(4) and study its phenomenology beyond the leading low-energy effective lagrangian approximation. Our basic goal is to introduce in a controllable and simple way the…
We present an implementation of the Electroweak Chiral Lagrangian (also denoted as Higgs Effective Theory) in several high energy physics Mathematica packages. In particular, we implement the bosonic part of the electoweak Lagrangian up to…
The status of various precisely measured electroweak parameters is reviewed. Natural relations among them are shown to constrain the Higgs mass, m_H, via quantum loop effects to relatively low values. A comparison with direct Higgs searches…
In the light of the LHC, we revisit the implications of a fourth generation of chiral matter. We identify a specific ensemble of particle masses and mixings that are in agreement with all current experimental bounds as well as minimize the…
Contrary to what is sometimes stated, the current electroweak precision data easily allow for massive composite resonance states at the natural EW scale, i.e., well over the TeV. The oblique parameters S and T are analyzed by means of an…
We analize the most general low-energy effective lagrangian including local parity violating terms parametrized by an axial chemical potential $\mu_5$. This result is obtained following the external source method, up to $\mathcal{O}(p^4)$…
Using a manifestly gauge-invariant approach we show that the set of low-energy constants in the electroweak chiral Lagrangian currently used in the literature is redundant. In particular, by employing the equations of motion for the gauge…
Effective theories provide a powerful tool for testing the Standard Model and for searching for the effects of new physics in a model-independent manner. In general one assumes that the effects of new physics characterized by a high-energy…
We study the one-loop renormalization the standard model with anomalous Higgs couplings ($O(p^2)$) by using the background field method, and provide the whole divergence structure at one loop level. The one-loop divergence structure…
Matching conditions relate couplings to particle masses. We discuss the importance of one-loop matching conditions in Higgs and top-quark sector as well as the choice of the matching scale. We argue for matching scales $\mu_{0,t} \simeq…
If the top is very heavy, m_t >> M_Z, the dominant radiative correction effects in all electroweak precision tests can be exactly characterized in terms of two quantities, the rho-parameter and the GIM violating Z -> b bbar coupling. These…
We consider the electroweak chiral Lagrangian, including a light scalar boson, in the limit of small $\xi=v^2/f^2$. Here $v$ is the electroweak scale and $f$ is the corresponding scale of the new strong dynamics. We show how the…
Using a chiral Lagrangian we show that strongly interacting models of electroweak symmetry breaking are not in conflict with precision data. Such models, like Technicolor, need not lead to a heavy Higgs-like signal. Furthermore, the allowed…
We study the inter-relations that exist between the present experimental bounds on the Higgs mass, as obtained from radiative corrections to $m_W$, and the effective parameters, $\alpha_i$ and $\Lambda$. We find that the SM bounds on $m_H$,…
We add a nonstandard higgs into the traditional bosonic part of electroweak chiral Lagrangian, in purpose of finding out the contribution to EWCL coefficients from processes with internal line higgs particle. To construct the effective…
Theoretical arguments suggest that the Higgs sector of the standard model is an effective theory. We parametrize the new physics by means of an effective Lagrangian technique and study its effect on the energy of the electroweak sphaleron.…
We match the electroweak chiral Lagrangian with two singlet scalars to the next-to-minimal composite Higgs model with $ SO(6)/SO(5) $ coset structure and extract the scalar divergences to one loop. Assuming the additional scalar to be…
We compute the one-loop matching between the Standard Model Effective Field Theory and the low-energy effective field theory below the electroweak scale, where the heavy gauge bosons, the Higgs particle, and the top quark are integrated…
We consider the general chiral effective action which parametrizes the nonlinear realization of the spontaneous breaking of the electroweak symmetry with a light Higgs, and compute the one-loop ultraviolet divergences coming from Higgs and…