Related papers: Dark Strings and their Couplings to the Standard M…
A coupling of a scalar, charged under an unbroken global U(1) symmetry, to the Standard Model via the Higgs portal is one of the simplest gateways to a dark sector. Yet, for masses $m_{S}\geq m_{H}/2$ there are few probes of such an…
We study a simple extension of Standard Model where the gauge group is extended by an additional $U(1)_X$ gauge symmetry. Neutrino mass arise both at tree level as well as radiatively by the anomaly free addition of one singlet fermion…
Axionic cosmic string solutions are investigated in a superstring motivated model with a pseudo-anomalous U(1) gauge symmetry. The inclusion of a gauge field and spatially varying dilaton allow local defect solutions with finite energy per…
We study the scalar Higgs sector of the next-to-minimal supersymmetric standard model with an extra U(1), which has two Higgs doublets and a Higgs singlet, in the light leptophobic $Z'$ scenario where the extra neutral gauge boson $Z'$ does…
We show that supersymmetry can be broken mainly by hidden matter condensates in the observable matter direction in generic superstring models. This happens only when the fields whose VEVs give masses to hidden matter do not decouple at the…
We study several aspects of supersymmetric models with a $U(1)_R$ symmetry where the Higgs doublet is identified with the superpartner of a lepton. We derive new, stronger bounds on the gaugino masses based on current measurements, and also…
We discuss some cosmological implications of extensions of the Standard Model with hidden sector scalars coupled to the Higgs boson. We put special emphasis on the conformal case, in which the electroweak symmetry is broken radiatively with…
Stringent constraints from direct detection experiments and the Large Hadron Collider motivate us to consider models in which the dark matter does not directly couple to the Standard Model, but that instead annihilates into hidden sector…
A vector-like colorless fermion doublet and a singlet added to the Standard Model allow a consistent interpretation of dark matter in terms of the lightest neutral particle, as they may help in obtaining successful gauge coupling…
We suggest that dark matter can be identified with a stable composite fermion X^0, that arises within the holographic AdS/CFT models, where the Higgs boson emerges as a composite pseudo-goldstone boson. The predicted properties of X^0…
We explore the parameter space of a U(1) extension of the standard model -- also called the super-weak model -- from the point of view of explaining the observed dark matter energy density in the Universe. The new particle spectrum contains…
We address the mass ranges of new neutral gauge bosons and constraints on the accompanying exotic particles as predicted by a class of superstring models. Under certain assumptions about the supersymmetry breaking parameters we show that…
The recently announced Higgs discovery marks the dawn of the direct probing of the electroweak symmetry breaking sector. Sorting out the dynamics responsible for electroweak symmetry breaking now requires probing the Higgs interactions and…
In this work we study a classically scale invariant extension of the Standard Model that can explain simultaneously dark matter and the baryon asymmetry in the universe. In our set-up we introduce a dark sector, namely a non-Abelian SU(2)…
We propose the minimal, lepton-number conserving, SU(3)xSU(2)xU(1) gauge-singlet, or phantom, extension of the Standard Model. The extension is natural in the sense that all couplings are of O(1) or forbidden due to a phantom sector global…
Gauge Higgs Unification in Warped Extra Dimensions provides an attractive solution to the hierarchy problem. The extension of the Standard Model gauge symmetry to $SO(5)xU(1)_X$ allows the incorporation of the custodial symmetry $SU(2)_R$…
In a previous work, a classically scale invariant extension of the standard model was proposed, as a potential candidate for resolving the hierarchy problem, by minimally introducing a complex gauge singlet scalar, and generating radiative…
We investigate the impact of interactions between hidden sectors and the discovered Higgs boson $h_{125}$, allowing for additional invisible decay channels of $h_{125}$. We perform $\chi^2$-fits to the measurements of the Higgs-boson cross…
We consider a simple extension of the Standard Model (SM) with a vector-like lepton and a local $U(1)'$ symmetry, motivated by the recent experimental anomalies in the muon $g-2$ and the $W$ boson mass. The $U(1)'$ symmetry is spontaneously…
In this research we consider a $U(1)_X$ gauge boson acting as a dark matter candidate. The vector dark matter (DM) gets mass when a complex singlet scalar breaks the gauge symmetry spontaneously, adding a second Higgs boson to the spectra.…