Related papers: Milli-Charged Dark Matter in Quantum Gravity and S…
A new scenario for creation of galactic magnetic fields is proposed which is operative at the cosmological epoch of the galaxy formation, and which relies on unconventional properties of dark matter. Namely, it requires existence of feeble…
In recent years it has been realized that in string/$M$ theories compactified to four dimensions which satisfy cosmological constraints, it is possible to make some generic predictions for particle physics and dark matter: a non-thermal…
In this semi-technical review we discuss string theory (and all that goes by that name) as a framework for a quantum theory of gravity. This is a new paradigm in theoretical physics that goes beyond relativistic quantum field theory. We…
We consider a model where a light scalar field (with mass $\lesssim 30\, {\rm eV}$), conjectured to be dark matter, has a non-minimal coupling to gravity. In the non-relativistic limit, this new coupling introduces a self-interaction term…
Over the past few decades, the hypothetically dark photon has been extensively studied from both phenomenological and experimental perspectives. It should be noted that the local symmetry for dark photon does not gauge the standard model…
Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…
The existence of the neutrino mass and flavor mixing have been experimentally verified. These phenomena strongly motivate to extend the Standard Model (SM). Amongst many possibilities, a simple and interesting extension of the SM can be…
Quantum Electrodynamics can be formulated as the theory of an antisymmetric tensor gauge field. In this formulation the topological current of this field appears as an additional source for the electromagnetic field. The topological charge…
String theory is the most promising candidate for the theory unifying all interactions including gravity. It has an extremely difficult dynamics. Therefore, it is useful to study some its simplifications. One of them is non-critical string…
We propose that charged leptons are the `baryons' of the gauge dynamics subject to a SU(2)$_{e}$$\timesSU(2)_{\mu}\timesSU(2)_{\tau}$ symmetry. The `mesons' of this theory are neutral and thus candidates for dark matter. There is, in…
Expressions for electric and magnetic charges of dyons, which become massless in the strong-coupling limit of the supersymmetric N=2 gauge theory with an arbitrary gauge group are presented. Transitions into different vacua of the N =1…
Dark Matter models that employ a vector portal to a dark sector are usually treated as an effective theory that incorporates kinetic mixing of the photon with a new U(1) gauge boson, with the $Z$ boson integrated out. However, a more…
The linearized Einstein theory in the approximately flat time-space is modified accounting for a massive graviton as a dark matter in the universe. On the basis of magnetic-type Maxwell- Proca -Vlasov equations, the interactions of the…
We investigate the relation between the existence of mass inflation and model parameters of string-inspired gravity models. In order to cover various models, we investigate a Brans-Dicke theory that is coupled to a U(1) gauge field. By…
We consider a string theory with two types of strings with geometric interaction. We show that the theory contains strings with constant Dirichlet boundary condition and those strings are glued together by 2-d topological gravity with…
I discuss various aspects of background independence in the context of string theory, for which so far we have no manifestly background independent formulation. After reviewing the role of background independence in classical Einstein…
In Abelian theories of monopoles the magnetic charge is required to be enormous. Using the electric-magnetic duality of electromagnetism it is argued that the existence of such a large, non-perturbative magnetic coupling should lead to a…
An extension of the Standard Model is studied, in which two new vector bosons are introduced, a first boson $Z'$ coupled to the SM by the usual minimal coupling, producing an enlarged gauge sector in the SM. The second boson $A'$ field, in…
A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark $U(1)'$ charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge…
The quantum field theory of gravitation is constructed in terms of Lagrangian density of Dirac fields which couple to the electromagnetic field $A_\mu$ as well as the gravitational field $\cal G$. The gravity appears in the mass term as $…