Related papers: Scalar Fields in Particle Physics
In recent years, evidence for lepton flavour universality violation beyond the Standard Model has been accumulated. In this context, a singly charged $SU(2)_L$ singlet scalar ($\phi^\pm$) is very interesting, as it can only have flavour…
Scalar sectors with several Higgs doublets, a CP invariant potential, and a CP violating vacuum, possess a mass spectrum in which, unexpectedly, new scalars cannot have masses much larger than the electroweak scale once perturbativity…
In multi-Higgs-doublet models, the alignment in flavour space of all Yukawa matrices coupling to a given right-handed fermion guarantees the absence of tree-level flavour-changing neutral couplings, while introducing new sources of CP…
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…
CP violation induced by resonant transitions of a scalar to a pseudoscalar intermediate state is analyzed within a gauge-invariant resummation approach based on the pinch technique. Necessary conditions governing the resonant enhancement of…
Flavor violating interactions of the Higgs boson are a generic feature of models with extended electroweak symmetry breaking sectors. Here, we investigate CP violation in these interactions, which can arise from interference of tree-level…
We propose a model of soft CP violation in which the CP violating mechanism naturally lies only in the charged Higgs sector. The charged Higgs mechanism not only accounts for the measured value of the CP-violating parameter $\epsilon$ but…
Extended Higgs sectors are often introduced to explain phenomena beyond the standard model (BSM). The existence of multiple scalar fields may cause the Landau pole below the Planck scale. In this case, the low-energy theory may be replaced…
It is widely believed that existing electroweak data requires a Standard Model Higgs to be light while electroweak and flavour physics constraints require other scalars charged under the Standard Model gauge couplings to be heavy. We…
We conjecture that there exists a scalar bound state for every pair of fundamental fermions at a UV (`composite') scale, $\Lambda\gg v_{\text{weak}}$. This implies a large number of universally coupled, sub-critical Higgs doublets. All but…
Searches for new neutral Higgs bosons of an extended Higgs sector at the LHC can be interpreted in the framework of the two-Higgs doublet model. By employing generic flavor-aligned Higgs-fermion Yukawa couplings, we propose an analysis that…
We study the scalar sector of the Two Measures Field Theory (TMT) model in the context of cosmological dynamics. The scalar sector includes the inflaton \phi and the Higgs \upsilon fields. The model possesses gauge and scale invariance. The…
In many extensions of the Standard Model flavour changing neutral current processes can be mediated by tree-level heavy neutral scalars and/or pseudo-scalars H^0(A^0). This generally introduces new sources of flavour violation and CP…
The results of an extensive flavour physics analysis in the Littlest Higgs model with T-parity are presented. In particular, mixing and CP-violation in K^0 and B^0_{d,s} systems have been studied. Several scenarios defined by the values of…
The charged fermion mass matrices are invariant under $U(1)^3$ symmetry linked to the fermion number transformation. Under the condition that the definition of this symmetry in arbitrary weak basis does not depend upon Higgs parameters such…
We investigate the scalar and pseudoscalar spectrum of the $SU(2)$ gauge theory with $N_f=2$ flavours of fermions in the fundamental representation using non perturbative lattice simulations. We provide first benchmark estimates of the mass…
These notes are based on the lectures I gave at the 2015 European School of High-Energy Physics (ESHEP2015). I discuss 1) flavor physics within the Standard Model, 2) effective field theories and Minimal Flavor Violation, 3) flavor physics…
It is shown that a two-Higgs doublet model with Vacuum CP Violation and Approximate Global $U(1)$ Family Symmetries (AGUFS) may provide one of the simplest and attractive models in understanding origin and mechanisms of CP violation at the…
The fundamental constraint on two Higgs doublet models comes from the requirement of sufficiently suppressing flavor-changing neutral currents. There are various standard approaches for dealing with this problem, but they all tend to share…
The Higgs sector of models beyond the standard model requires special attention and study, since through them, a natural explanation can be offered to current questions such as the big differences in the values of the masses of the quarks…