Related papers: Enhanced Long-Lived Dark Photon Signals at the LHC
We propose a scalar dark matter model featuring a hidden gauge symmetry, denoted as U(1)_X, with two complex scalars, Phi and S. In this framework, Phi spontaneously breaks the U(1)_X gauge symmetry, while S serves as a viable dark matter…
We investigate a novel production mechanism for long-lived dark photons at the LHC, arising from dark radiation emitted from $\chi$ in $Z\to\bar{\chi}\chi$ decays, where $\chi$ is a fermionic dark matter candidate. The effective $Z\chi\chi$…
We study a class of simplified dark matter models in which dark matter couples directly with a mediator and a charged lepton. This class of Lepton Portal dark matter models has very rich phenomenology: it has loop generated dark matter…
In this paper, we study an extension of the standard model with a vector-like generation of leptons. This model provides a viable dark matter candidate and a possibility to enhance the Higgs decay rate into a pair of photons. We evaluate…
Hidden sectors with light extra U(1) gauge bosons, so-called hidden photons, have recently attracted some attention because they are a common feature of physics beyond the Standard Model like string theory and supersymmetry and additionally…
We consider axion-mediated dark matter models motivated by Fermi gamma ray line at 130 GeV, where anomaly interactions of an axion-like scalar mediate a singlet Dirac fermion dark matter (DM) to electroweak gauge bosons. In these models,…
We present the Large Hadron Collider (LHC) discovery potential in the $Z'$ and heavy neutrino sectors of a $U(1)_{B-L}$ enlarged Standard Model also encompassing three heavy Majorana neutrinos. This model exhibits novel signatures at the…
Motivated by the absence of any clear signal of physics beyond the Standard Model at the LHC after Run I, we discuss one possible slight hint of new physics and one non-minimal extension of the Standard Model. In the first part we provide a…
A dark sector containing a Higgs field and a dark photon coupled to visible photons via a small kinetic mixing is considered. The mass of the dark gauge boson becomes rescaled by the parameter involved in the kinetic mixing. We also…
We investigate the phenomenology of an extension of the Standard Model (SM) by a non-abelian gauge group $SU(2)_{HS}$ where all SM particles are singlets under this gauge group, and a new scalar representation $\phi$ that is singlet under…
We introduce a perturbative extension of the standard model featuring a new dark matter sector together with a 125 GeV Higgs. The new sector consists of a vector-like heavy electron E, a complex scalar electron S and a standard model…
We investigate the search prospects for new scalars beyond the Standard Model (SM) at the Large Hadron Collider (LHC). In these studies two real scalars $S$ and $\chi$ have been introduced in a two Higgs doublet model (2HDM), where $S$ is a…
We explore the potential for detecting the inelastic dark model (DM) with an additional $U(1)_D$ gauge symmetry at various types of lepton colliders. The new gauge boson $Z'$ resulting from the spontaneous breaking of $U(1)_D$ can act as a…
We study the impact of fermionic dark matter (DM) on projected Higgs precision measurements at the Circular Electron Positron Collider (CEPC), including the one-loop effects on the $e^+e^-\to Zh$ cross section and the Higgs boson diphoton…
We investigate a dark sector containing a pair of light non-degenerate scalar particles, with masses in the MeV-GeV range, coupled to the visible sector through heavier mediators. The heaviest dark state is long-lived, and its decays offer…
We consider a hidden sector model of dark matter which is charged under a hidden U(1)_X gauge symmetry. Kinetic mixing of U(1)_X with the Standard Model hypercharge U(1)_Y is allowed to provide communication between the hidden sector and…
We construct a model containing a viable dark matter candidate, in the framework of left-right symmetry, which can explain both width and cross-section of the observed 750 GeV diphoton excess at the LHC. We introduce a fermion quintuplet…
We propose a model of multi-component dark matter with magnetic moments to explain the 130 GeV gamma-ray line hinted by the Fermi-LAT data. Specifically, we consider a U(1)_X dark sector which contains two vector-like fermions besides the…
The Large Hadron Collider (LHC) has measured the Higgs boson couplings with the heavier particles of the Standard Model (SM), and they seem to lay on a single line as function of the particle mass, as predicted in the SM. However a complete…
In light of the recent observation of the Fermi-LAT 130 GeV gamma-ray line, we suggest a model of scalar dark matter in hidden sector, which can decay into two (hidden) photons. The process is radiatively induced by a GUT scale fermion in…