8,505 research outputs found
Complex Scalar DM in a B-L Model
In this work, we implement a complex scalar Dark Matter (DM) candidate in a
gauge extension of the Standard Model. The model contains three
right handed neutrinos with different quantum numbers and a rich scalar sector,
with extra doublets and singlets. In principle, these extra scalars can have
VEVs ( and for the extra doublets and singlets,
respectively) belonging to different energy scales. In the context of
, which allows to obtain naturally
light active neutrino masses and mixing compatible with neutrino experiments,
the DM candidate arises by imposing a symmetry on a given complex
singlet, , in order to make it stable. After doing a study of the
scalar potential and the gauge sector, we obtain all the DM dominant processes
concerning the relic abundance and direct detection. Then, for a representative
set of parameters, we found that a complex DM with mass around GeV, for
example, is compatible with the current experimental constraints without
resorting to resonances. However, additional compatible solutions with heavier
masses can be found in vicinities of resonances. Finally, we address the issue
of having a light CP-odd scalar in the model showing that it is safe concerning
the Higgs and the boson invisible decay widths, and also the energy
loss in stars astrophysical constraints.Comment: 20 pages, 3 figure
Colonial Origins of Inequality in Hispanic America? Some reflections based on new empirical evidence
This paper attempts at contributing to the ongoing debate on the historical roots of the high economic inequality of contemporary Iberian America. Basically empirical, our approach departs from mainstream scholarship. We show new data on wages and heights in several viceroyalties that: 1) suggest relatively medium to high levels of material welfare among the commoners in Bourbon Hispanic America; 2) allow us to build indexes of economic inequality. An international comparison of those indexes casts some doubts on the widely accepted view that Viceroyal America’s economy was exclusively based on extremely unequal or extractive institutions, as it has been popularized by the influential works by Engerman and Sokoloff (1994, 2002, 2005), Acemoglu et al. (2002).economic inequality, Iberian America, Viceroyal America’s economy
Supersymmetric 3-3-1 model with right-handed neutrinos
We consider the supersymmetric extension of the 3-3-1 model with right-handed
neutrinos. We study the mass spectra in the scalar and pseudoscalar sectors,
and for a given set of the input parameters, we find that the lightest scalar
in the model has a mass of 130 GeV and the lightest pseudoscalar has mass of 5
GeV. However, this pseudoscalar decouples from the at high energy scales
since it is almost a singlet under .Comment: Revtex4, 16 pages, no figure
Symmetry breaking and clustering in a vibrated granular gas with several macroscopically connected compartments
The spontaneous symmetry breaking in a vibro-fluidized low-density granular
gas in three connected compartments is investigated. When the total number of
particles in the system becomes large enough, particles distribute themselves
unequally among the three compartments. Particles tend to concentrate in one of
the compartments, the other two having the (relatively small) same average
number of particles. A hydrodynamical model that accurately predicts the
bifurcation diagram of the system is presented. The theory can be easily
extended to the case of an arbitrary number of connected compartments
Reply to ``Comment on `Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions' ''
We demonstrate that in the process of deducing the constraint on the
electroweak mixing angle in our paper, we have indeed been working
with three mass scales while implementing (331) model.Comment: Revtex, 3pages, Reply to hep-ph/9902448, Submitted to Phys. Rev.
Quantum interference oscillations of the superparamagnetic blocking in an Fe8 molecular nanomagnet
We show that the dynamic magnetic susceptibility and the superparamagnetic
blocking temperature of an Fe8 single molecule magnet oscillate as a function
of the magnetic field Hx applied along its hard magnetic axis. These
oscillations are associated with quantum interferences, tuned by Hx, between
different spin tunneling paths linking two excited magnetic states. The
oscillation period is determined by the quantum mixing between the ground S=10
and excited multiplets. These experiments enable us to quantify such mixing. We
find that the weight of excited multiplets in the magnetic ground state of Fe8
amounts to approximately 11.6%.Comment: Accepted in Phys. Rev. Let
Conformal mapping of ultrasonic crystals: confining ultrasound and cochlear-like wave guiding
Conformal mapping of a slab of a two-dimensional ultrasonic crystal generate
a closed geometrical arrangement of ultrasonic scatterers with appealing
acoustic properties. This acoustic shell is able to confine ultrasonic modes.
Some of these internal resonances can be induced from an external wave source.
The mapping of a linear defect produces a wave-guide that exhibits a
spatial-frequency selection analogous to that characteristic of a synthetic
"cochlea". Both, experimental and theoretical results are reported here.Comment: 4 pages, 4 figure
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