Related papers: Characterizing Invisible Electroweak Particles thr…
Multiple electroweak phase transitions occurring sequentially in the early universe can give rise to intriguing phenomenology, compared to the typical single-step electroweak phase transition. In this work, we investigate this scenario…
We investigate the sensitivity to weakly interacting scalar dark matter from future determination of electroweak oblique parameters in the Circular Electron-Positron Collider (CEPC) project. As illuminating examples, three dark matter…
We point out that the ratio of $W^+ W^- \to W^+ W^-$ and $W^+W^- \to ZZ$ cross sections is a sensitive probe of the dynamics of electroweak symmetry breaking, in the CM energy region $\sqrt {s_{\rm ww}^{}} \agt 1$~TeV where vector boson…
We analyze the effective couplings of a light, spinless, gauge-singlet particle $\phi$ to on-shell photons. Starting from the most general theory at the electroweak scale, which allows for CP-violating interactions suppressed by inverse…
The top quark may hold the key to new physics associated with the electroweak symmetry-breaking sector, given its large mass and enhanced coupling to the Higgs sector. We systematically categorize generic interactions of a new particle that…
If the gravitino G is very light and all the other supersymmetric particles are above threshold, supersymmetry may still be found at colliders, by looking at processes with only gravitinos and ordinary particles in the final state. We…
We derive the Lagrangian and Feynman rules up to bilinear scalar fields for the mixed Higgs-radion eigenstates interacting with Standard Model particles confined to a 3-brane in Randall-Sundrum warped geometry. We use the results to compute…
High energy e$^+$e$^-$ colliders offer unique possibility for the most general dark matter search based on the mono-photon signature. Analysis of the energy spectrum and angular distributions of photons from the initial state radiation can…
By exploiting the correlation between charge and spin polarisation asymmetries in t-tbar, we show that combining the two observables could identify the presence of quasi-degenerate states in a resonant signal at the LHC. As an example, we…
The proposed electron-proton collider LHeC is a unique facility where electroweak interactions can be studied with a very high precision in a largely unexplored kinematic regime of spacelike momentum transfer. We have simulated inclusive…
The electroweak symmetry breaking (EWSB) sector of the Standard Model can be far richer and more interesting than the usual single scalar doublet model. We explore scenarios where the EWSB sector is nearly scale invariant and consequently…
It is possible to ameliorate the Higgs vacuum stability problem by switching over to two Higgs doublet models (2HDM), ensuring a stable electroweak vacuum up to the Planck scale, even though the top quark mass may be on the high side.…
We examine the production of an invisible state $X$ together with a photon, $e^+e^- \to \gamma +X$, at electron positron colliders and present measurement strategies that can detect the spin of the invisible state as well as the underlying…
The mechanism of the electroweak symmetry-breaking (EWSB) is studied in the context of the heavy top quark, whose large mass may provide a clue as to the mechanism which generates the mass of the $W^\pm$ and $Z$ bosons. As a result, it…
Electroweak symmetry breaking explains the origin of the masses of elementary particles through their interactions with the Higgs field. Besides the measurements of the Higgs boson properties, the study of the scattering of massive vector…
In high-energy leptonic collisions well above the electroweak scale, the collinear splitting mechanism of the electroweak gauge bosons becomes the dominant phenomena via the initial state radiation and the final state showering. We point…
We show that weak scale vector-like fermions with order one couplings to the Higgs can lead to a novel mechanism for a strongly first-order electroweak phase transition (EWPhT), through their tendency to drive the Higgs quartic coupling…
In some models of electro-weak interactions the W and Z bosons are considered composites, made up of spin-one-half subconstituents. In these models a spin zero counterpart of the W and Z boson naturally appears, whose higher mass can be…
Recently, a new class of realistic models for electroweak symmetry breaking have been constructed, without supersymmetry. These theories have naturally light Higgs bosons and perturbative new physics at the TeV scale. We describe these…
In most supersymmetric theories, charginos $\tilde{\chi}^\pm_{1,2}$, mixtures of charged color-neutral gauginos and higgsinos, belong to the class of the lightest supersymmetric particles. They are easy to observe at $e^+e^-$ colliders. By…