Related papers: Flavour Dynamics with General Scalar Fields
In many extensions of the Standard Model, the alignment in flavor space of the fermion mass matrices and the Yukawa coupling matrices can be broken. The physical scalar boson $h(125)$ could then have flavor changing couplings. In this talk,…
We consider an extension of the standard electroweak theory with gauge group $SU(2)_L \times SU(2)_R \times U(1)_{\tilde{Y}}$, where the gauge bosons of the extra $SU(2)_R$ factor do not couple to ordinary fermions. We show that precision…
In this paper we give a variation of the gauge procedure which employs a scalar gauge field, $B (x)$, in addition to the usual vector gauge field, $A_\mu (x)$. We study this variant of the usual gauge procedure in the context of a complex…
We study confining gauge theories with fermions vectorial under the SM that produce a Higgs doublet as a Nambu-Goldstone boson. The vacuum misalignment required to break the electro-weak symmetry is induced by an elementary Higgs doublet…
The Standard Model does not provide any dynamical explanation of the existence of different families of fermions. To account for this experimental fact, it just replicates three times its single-family gauge structure. The equal-charge…
We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model…
We examine the decays $t\rightarrow c\gamma$ and $c Z^0$ in the Standard Model with an extra scalar doublet and no discrete symmetry preventing tree-level flavour changing neutral currents. The Yukawa couplings of the new scalars are…
We consider a SU(2)$ \otimes $U(1) gauge theory with many scalar doublets, but without fermions. We devise a systematic method of constructing quantities which are invariant under changes of basis of the scalar fields, but acquire a minus…
In the most general two-Higgs doublet model (generally referred to as Model III), tree level flavor changing neutral couplings exist. It has been noted that the most natural value for such a coupling is of the order of the geometric mean of…
In multi-Higgs-doublet models, requiring simultaneously that (i) CP violation only arises spontaneously, (ii) tree level scalar flavour changing couplings are absent and (iii) the fermion mixing matrix is CP violating, can only be achieved…
A plethora of ultraviolet completions of the Standard Model have extra U(1) gauge symmetries. In general, the associated massive $Z^\prime$ gauge boson can mediate flavor-changing neutral current processes at tree level. We consider a…
The alignment in flavour space of the Yukawa matrices of a general two-Higgs-doublet model results in the absence of tree-level flavour-changing neutral currents. In addition to the usual fermion masses and mixings, the aligned Yukawa…
In this paper we investigate a natural extension of the Standard Model that involves varying coupling constants. This is a general expectation in any fundamental theory such as string theory, and there are good reasons for why new physics…
Effective type I string models allow stabilization of the dilaton and moduli fields with only a single gaugino condensate. We show that, as well as breaking supersymmetry, the stabilization can spontaneously break CP. We find that this…
The models with the gauge group $SU(3)_c\times SU(3)_L \times U(1)_X$ (331-models) have been advocated to explain why there are three fermion generations in Nature. As such they can provide partial understanding of the flavour sector. The…
We revisit a recent solution to the flavor hierarchy problem based on the paradigm that Yukawa couplings are, rather than fundamental constants, effective low energy couplings radiatively generated by interactions in a hidden sector of the…
Fermion masses and mixing matrices can be described in terms of spontaneously broken (global or gauge) flavor symmetries. We propose a little-Higgs inspired scenario in which an SU(2)xU(1) gauge flavor symmetry is spontaneously (and…
I build a SU(2)left x U(1) electroweak gauge theory of J=0 mesons, which transform like sets of fermion-antifermion composite fields. SU(2)left x U(1) is embedded in a natural way, compatible with the Glashow-Salam-Weinberg model for…
One exciting possibility of new physics beyond the Standard Model is that the fundamental Higgs sector is replaced by a strongly-interacting gauge theory, known as technicolor. A viable theory must break chiral symmetry dynamically, like in…
We consider the approximate U(2)^3 flavour symmetry exhibited by the quark sector of the Standard Model and all its possible breaking terms appearing in the quark Yukawa couplings. Taking an Effective Field Theory point of view, we…