3,996 research outputs found
Sterile neutrino dark matter, CDMS-II and a light Higgs boson
We add a singlet right handed neutrino plus a charged and a neutral singlet
scalars to the standard model. This extension includes a discrete symmetry such
that we obtain a heavy sterile neutrino which couples only to the electron and
the new scalars. In this sense the singlet neutrino does not mix with ordinary
ones and thus has no effect on Big Bang Nucleosynthesis. However, such sterile
neutrino can be in equilibrium with electroweak particles in the early Universe
due to its couplings to electrons and also because the Higgs boson mixes with
the singlet scalars. We obtain that the sterile neutrino constitutes a dark
matter candidate and analyze its direct detection in the light of current
experiments. Our results show that if such a sterile neutrino is realized in
nature, and CDMS-II experiment confirms its positive signal, dark matter
demands a rather light Higgs boson with new Physics at some 500 GeV scale.Comment: 16 pages, 13 figures, uses axodraw.st
R-parity as a residual gauge symmetry : probing a theory of cosmological dark matter
We present a non-supersymmetric scenario in which the R-parity symmetry arises as a result of spontaneous gauge symmetry breaking,
leading to a viable Dirac fermion WIMP dark matter candidate. Direct detection
in nuclear recoil experiments probes dark matter masses around TeV for
TeV consistent with searches at the LHC, while lepton
flavor violation rates and flavor changing neutral currents in neutral meson
systems lie within reach of upcoming experiments.Comment: 7 pages, 3 figure
Right-handed Neutrino Dark Matter, Neutrino Masses, and non-Standard Cosmology in a 2HDM
We explore the dark matter phenomenology of a weak-scale right-handed
neutrino in the context of a Two Higgs Doublet Model. The expected signal at
direct detection experiments is different from the usual spin-independent and
spin-dependent classification since the scattering with quarks depends on the
dark matter spin. The dark matter relic density is set by thermal freeze-out
and in the presence of non-standard cosmology, where an Abelian gauge symmetry
is key for the dark matter production mechanism. We show that such symmetry
allows us to simultaneously address neutrino masses and the flavor problem
present in general Two Higgs Doublet Model constructions. Lastly, we outline
the region of parameter space that obeys collider, perturbative unitarity and
direct detection constraints.Comment: 27 pages, 3 figures. Matches the version accepted for publication in
JCA
Logarithmic corrections to gap scaling in random-bond Ising strips
Numerical results for the first gap of the Lyapunov spectrum of the self-dual
random-bond Ising model on strips are analysed. It is shown that finite-width
corrections can be fitted very well by an inverse logarithmic form, predicted
to hold when the Hamiltonian contains a marginal operator.Comment: LaTeX code with Institute of Physics macros for 7 pages, plus 2
Postscript figures; to appear in Journal of Physics A (Letter to the Editor
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