Related papers: Astrophysical constraints on millicharged atomic d…
Deep inelastic scattering of $e^{\pm}$ off protons is sensitive to contributions from "dark photon" exchange. Using HERA data fit to HERA's parton distribution functions, we obtain the model-independent bound $\epsilon \lesssim 0.02$ on the…
We examine the milli-charged dark matter scenario from a string theory perspective. In this scenario, kinetic and mass mixings of the photon with extra U(1) bosons are claimed to give rise to small electric charges, carried by dark matter…
We consider an inelastic dark matter model, where a fermion is charged under a broken U(1) gauge symmetry, and introduce a tiny Majorana mass term to split the fermion into two states with the light one being a dark matter candidate. If the…
Composite dark matter (DM) comprised of electrically charged constituents can interact with the electromagnetic field via the particle's dipole moment. This interaction results in a dispersive optical index of refraction for the DM medium.…
Superheavy dark matter can satisfy the observed dark matter abundance if the stability condition is fulfilled. Here, we propose a new Abelian gauge symmetry ${\rm U(1)}_H$ for the stability of superheavy dark matter as the electromagnetic…
We present updated constraints on 'light' Dark Matter (DM) particles with masses between 1 MeV and 5 GeV. In this range, we can expect DM-produced $e^\pm$ pairs to up-scatter low-energy ambient photons in the Milky Way via the Inverse…
We use the isotropy of the Cosmic Microwave Background to place stringent constraints on a possible electrical charge asymmetry of the universe. We find the excess charge per baryon to be $q_{e-p}<10^{-26}e$ in the case of a uniform…
We present new observational constraints on the elastic scattering of dark matter with electrons for dark matter masses between 10 keV and 1 TeV. We consider scenarios in which the momentum-transfer cross section has a power-law dependence…
In order to accommodate increasingly tighter observational constraints on dark matter, several models have been proposed recently in which dark matter particles are charged under some hidden gauge group. Hidden gauge charges are invisible…
Motivated by recent astrophysical observations of quasar absorption systems, we formulate a simple theory where the electron to proton mass ratio $\mu =m_{e}/m_{p}$ is allowed to vary in space-time. In such a minimal theory only the…
Dark photons, a generic class of light gauge bosons that interact with the Standard Model (SM) exclusively through kinetic mixing, arise naturally in many gauge extensions of the SM. Motivated by these theoretical considerations, we present…
Dark matter (DM) charged under a dark U(1) force appears in many extensions of the Standard Model, and has been invoked to explain anomalies in cosmic-ray data, as well as a self-interacting DM candidate. In this paper, we perform a…
We revisit constraints on dark matter that is charged under a $U(1)$ gauge group in the dark sector, decoupled from Standard Model forces. We find that the strongest constraints in the literature are subject to a number of mitigating…
We explore the phenomenology of a class of models where the dark matter particle can inelastically up-scatter to a heavier excited state via off-diagonal dipolar interactions with the interstellar plasma (gas or free electrons). The heavier…
We explore the cosmological consequences of kinetically mixed dark photons with a mass between 1 MeV and 10 GeV, and an effective electromagnetic fine structure constant as small as $10^{-38}$. We calculate the freeze-in abundance of these…
Gravitational positivity bounds provide consistency conditions for effective field theories with gravity. They turn out to be phenomenologically useful by providing lower bounds in parameters of new physics beyond the Standard Models (BSM).…
We consider the implications of an ultra-light fermionic dark matter candidate that carries baryon number. This naturally arises if dark matter has a small charge under standard model baryon number whilst having an asymmetry equal and…
We consider the consequences of a neutral dark-matter particle with a nonzero electric and/or magnetic dipole moment. Theoretical constraints, as well as constraints from direct searches, precision tests of the standard model, the cosmic…
Dark photons are predicted by various new physics models, and are being intensively studied in a variety of experiments. In the first part of this paper, we obtain partial wave unitarity constraints on the dark photon parameter space from…
New physics scenarios beyond the Standard Model predict the existence of milli-charged particles. So far, only spin-1/2 and spin-0 milli-charged particles have been considered in literature, leaving out the interesting case of spin-1. We…