Related papers: Slightly Massive Photon and Equivalence Principle
Limits for the applicability of the equivalence principle are considered in the context of low-energy effective field theories. In particular, we find a class of higher-derivative interactions for the gravitational and electromagnetic…
In this talk, I discuss possible bounds on the Lorentz and CPT violating parameters in the Higgs sector of the so called minimal standard model extension. The main motivation to this study is coming from the fact that unlike the parameters…
The supersymmetric one-loop contribution to the quark-lepton universality violation in the low-energy charged current weak interactions is studied. It is shown that the recent experimental data with the 1-$\sigma$ deviation from the…
In the Standard Model, all massive elementary particles acquire their masses by coupling to a background Higgs field with a non-zero vacuum expectation value. What is often overlooked is that each massive particle is also a source of the…
This article reviews the Little Higgs models of electroweak symmetry breaking and their phenomenology. Little Higgs models incorporate a light composite Higgs boson and remain perturbative until a scale of order 10 TeV, as required by…
The multiple point principle (MPP), according to which several vacuum states with the same energy density exist, is put forward as a fine-tuning mechanism predicting the ratio between the fundamental and weak scales in the Standard Model…
Severe constraints on parameters of the minimal supersymmetric standard model follow from a dynamical electroweak symmetry breaking mechanism dominated by top and stop loops. In particular, the lightest Higgs boson mass is expected to be…
The Higgs sector of the Minimal Supersymmetric Model (MSSM) is a CP-conserving two-Higgs doublet model that depends, at tree-level, on two Higgs sector parameters. In order to accurately determine the phenomenological implications of this…
Einstein-Maxwell theory implies the mixing of photons with gravitons in an external electromagnetic field. This process and its possible observable consequences have been studied at tree level for many years. We use the worldline formalism…
Light scalar particles with couplings of sub-gravitational strength, which can generically be called 'dilatons', can produce violations of the equivalence principle. However, in order to understand experimental sensitivities one must know…
We study the Higgs sector of the Minimal Supersymmetric Standard Model, in the context of proton-proton collisions at LHC and SSC energies. We assume a relatively heavy supersymmetric particle spectrum, and include recent results on…
We discuss an extension of the minimal Higgs triplet model with a classically conformal invariance and with a gauged $U(1)_{B-L}$ symmetry. In our scenario, tiny masses of neutrinos are generated by a hybrid contribution from the type-I and…
Within 2HDM, sizable deviations of the triple Higgs coupling and the two-photon Higgs width from their SM values can have a common origin. If SM-like scenario for the observed Higgs boson is realized, mentioned deviations can be either…
We analyze the contribution of the SUSY particles to the coupling of the lightest Higgs boson to two photons in supersymmetric theories. We discuss to what extent these contributions can be large enough to allow for a discrimination between…
Recently, a toy model was introduced to demonstrate that screening mechanisms in alternative theories of gravitation can hide additional effects. In this model a scalar field is charged under a $U(1)$ symmetry. In sufficiently compact…
A short summary of constraints on the parameter space of supersymmetric models is given. Experimental limits from high energy colliders, electroweak precision data, flavor and Higgs physics, and cosmology are considered. The main focus is…
We study the di-photon rate in Higgs decays within singlet extensions of the supersymmetric standard model. In particular we point out that light charginos as well as a light charged Higgs can significantly contribute to the corresponding…
We investigate transformations which are not symmetries of a theory but nevertheless leave invariant the set of all symmetry elements and representations. Generalizing from the example of a three Higgs doublet model with $\Delta(27)$…
With the Higgs search program already quite mature, there is the exciting possibility of discovering a new particle with rates near that of the SM Higgs. We consider models with a signal in $\gamma \gamma$ below the SM Higgs mass, taking…
We study the conditions of maximal $CP$ violation in the neutral Higgs mass matrix of the two Higgs doublet model. We get fixed values of $\tan\b$ and constraints on the Higgs potential parameters. Two neutral Higgs scalars are constrained…