2,040 research outputs found
Dark Spinors Hawking Radiation in String Theory Black Holes
The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is
derived, in the context of dark spinors tunnelling across the horizon. Since a
black hole has a well defined temperature, it should radiate in principle all
the standard model particles, similar to a black body at that temperature. We
investigate the tunnelling of mass dimension one spin-1/2 dark fermions, that
are beyond the standard model and are prime candidates to the dark matter.
Their interactions with the standard model matter and gauge fields are
suppressed by at least one power of unification scale, being restricted just to
the Higgs field and to the graviton likewise. The tunnelling method for the
emission and absorption of mass dimension one particles across the event
horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further
evidence for the universality of black hole radiation, further encompassing
particles beyond the standard model.Comment: 11 pages, improved version, to appear in AHE
VSR symmetries in the DKP algebra: the interplay between Dirac and Elko spinor fields
VSR symmetries are here naturally incorporated in the DKP algebra on the
spin-0 and the spin-1 DKP sectors. We show that the Elko (dark) spinor fields
structure plays an essential role on accomplishing this aim, unravelling hidden
symmetries on the bosonic DKP fields under the action of discrete symmetries.Comment: 17 page
Echoes of the gravitational decoupling: scalar perturbations and quasinormal modes of hairy black holes
The behavior of hairy black hole solutions, obtained by the gravitational
decoupling (GD) method, is investigated under scalar perturbations. The
quasinormal mode frequencies of such solutions are regulated by GD hair. The
numerically generated wave solutions are derived for a range of values for the
GD hairy black hole parameters, with higher-frequency modes very sensitive to
them. The results are confronted with the corresponding ones for the
Schwarzschild solution, whose deviations from it demonstrate a unique physical
identification of GD hairy black holes. The method here presented comprises the
first steps towards the obtainment of the observable signature of GD hairy
black holes at ground-based detectors, emitted from coalescing binary systems
of GD hairy black hole mergers in the ringdown phase.Comment: 15 pages, 6 figure
Flag-Dipole Spinor Fields in ESK Gravities
We consider the Riemann-Cartan geometry as a basis for the
Einstein-Sciama-Kibble theory coupled to spinor fields: we focus on and
conformal gravities, regarding the flag-dipole spinor fields, type-(4) spinor
fields under the Lounesto classification. We study such theories in specific
cases given for instance by cosmological scenarios: we find that in such
background the Dirac equation admits solutions that are not Dirac spinor
fields, but in fact the aforementioned flag-dipoles ones. These solutions are
important from a theoretical perspective, as they evince that spinor fields are
not necessarily determined by their dynamics, but also a discussion on their
structural (algebraic) properties must be carried off. Furthermore, the
phenomenological point of view is shown to be also relevant, since for
isotropic Universes they circumvent the question whether spinor fields do
undergo the Cosmological Principle.Comment: 18 pages, improved versio
Unveiling Mapping Structures of Spinor Duals
Following the program of investigation of alternative spinor duals
potentially applicable to fermions beyond the standard model, we demonstrate
explicitly the existence of several well-defined spinor duals. Going further we
define a mapping structure among them and the conditions under which sets of
such dual maps do form a group. We also study the covariance of bilinear
quantities constructed with the several possible duals, the invariant
eigenspaces of those group elements and its connections with spinors
classification, as well as dual maps defined as elements of group algebras.Comment: 11 pages, no figure
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