11,437 research outputs found
Diphoton decay for a GeV scalar boson in an model
In the context of a nonuniversal and anomaly free extension of the
standard model, we examine the decay of a GeV scalar singlet state,
, as a possible explanation of the observed diphoton excess
announced by the ATLAS and CMS collaborations at CERN-LHC collider. One-loop
decay to photons is allowed through three heavy singlet quarks and one charged
Higgs boson into the loop. We obtain, for different width approximations and
for masses of the exotic singlet quarks in the region GeV, a
production cross section compatible
with ATLAS and CMS collaborations data. We also include another scalar singlet,
, as a dark matter candidate that may couple with the 750 GeV scalar at
tree level with production cross sections in agreement with ATLAS and CMS.Comment: 5 figures, discussion extended, 2 new figure
Diphoton decay for a 750 GeV scalar boson in a model
We propose a new GUT model free from anomalies, with
a 750 GeV scalar candidate which can decay into two photons, compatible with
the recent diphoton signal reported by ATLAS and CMS collaborations. This model
gives masses to all fermions and may explain the 750GeV signal through one loop
decays to with charged vector and charged Higgs bosons, as well
as up- and electron-like exotic particles that arise naturally from the
condition of cancellation of anomalies of the group. We
obtain, for different width approximations, allowed mass regions from 900 GeV
to 3 TeV for the exotic up-like quark, in agreement with ATLAS and CMS
collaborations data.Comment: 4 figures, discussion extended, 1 new figur
Concentrations of Polychlorinated Biphenyls (PCBs), Polychlorinated Dibenzo-p-dioxins and Furans (PCDD/Fs), and Polybrominated Diphenyl Ethers (PBDEs) as Functions of Sample Depth in Killer Whale (Orcinus orca) Blubber
Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs) were examined as a function of depth in killer whale (Orcinus orca) blubber samples. Lipid-normalized concentrations of PCBs, PCDD/Fs, and PBDEs did not display significant variation with depth in three distinct blubber layers (outer, central, and inner). Significantly more variation in contaminant concentrations were observed with depth on a wet weight basis for the killer whale sample. The current study indicates that non-invasive microdart biopsy sampling methods commonly used for monitoring contaminants in marine mammals yield representative details on contaminant burdens for chlorinated and brominated aromatic compounds in marine mammal blubber, regardless of the quantity and type of blubber sampled, provided that lipid normalization is performed on resulting analytical determinations
Interactions and thermoelectric effects in a parallel-coupled double quantum dot
We investigate the nonequilibrium transport properties of a double quantum
dot system connected in parallel to two leads, including intradot
electron-electron interaction. In the absence of interactions the system
supports a bound state in the continuum. This state is revealed as a Fano
antiresonance in the transmission when the energy levels of the dots are
detuned. Using the Keldysh nonequilibrium Green's function formalism, we find
that the occurrence of the Fano antiresonance survives in the presence of
Coulomb repulsion. We give precise predictions for the experimental detection
of bound states in the continuum. First, we calculate the differential
conductance as a function of the applied voltage and the dot level detuning and
find that crossing points in the diamond structure are revealed as minima due
to the transmission antiresonances. Second, we determine the thermoelectric
current in response to an applied temperature bias. In the linear regime,
quantum interference gives rise to sharp peaks in the thermoelectric
conductance. Remarkably, we find interaction induced strong current
nonlinearities for large thermal gradients that may lead to several nontrivial
zeros in the thermocurrent. The latter property is especially attractive for
thermoelectric applications.Comment: 9 pages, 8 figure
Leptogenesis in the presence of exact flavor symmetries
In models with flavor symmetries in the leptonic sector leptogenesis can take
place in a very different way compared to the standard leptogenesis scenario.
We study the generation of a asymmetry in these kind of models in the
flavor symmetric phase pointing out that successful leptogenesis requires (i)
the right-handed neutrinos to lie in different representations of the flavor
group; (ii) the flavons to be lighter at least that one of the right-handed
neutrino representations. When these conditions are satisfied leptogenesis
proceeds due to new contributions to the CP violating asymmetry and -depending
on the specific model- in several stages. We demonstrate the validity of these
arguments by studying in detail the generation of the asymmetry in a
scenario of a concrete flavor model realization.Comment: 25 pages, 7 figures; version 2: A few clarifications added. Version
matches publication in JHE
Dependence of nonlocal Gilbert damping on the ferromagnetic layer type in FM/Cu/Pt heterostructures
We have measured the size effect in nonlocal Gilbert relaxation rate in
FM(t) / Cu (5nm) [/ Pt (2nm)] / Al(2nm) heterostructures, FM = \{
NiFe, CoFeB, pure Co\}. Common behavior is
observed for three FM layers, where the additional relaxation obeys both a
strict inverse power law dependence ,
and a similar magnitude
. As the tested FM layers
span an order of magnitude in spin diffusion length , the
results are in support of spin diffusion, rather than nonlocal resistivity, as
the origin of the effect
Estructura factorial y consistencia interna de la Escala de Severidad de Fatiga en población colombiana con enfermedades crónicas
El presente estudio de corte psicométrico, tuvo como objetivo analizar la estructura factorial y la
consistencia interna versión en español del cuestionario Fatigue Severity Scale (FSS) en población
colombiana de enfermos crónicos. Para ello se aplicó el cuestionario a 52 enfermos crónicos de la
ciudad de Villavicencio. El análisis factorial denota tres factores: el factor 1 denominado como
afectación fÃsica, el factor 2 denominado afectación social y finalmente el factor 3 denominado
afectación motivacional de la fatiga, que explican el 76,324% de la varianza total acumulada, y un alfa
de Cronbach de 870. Los resultados muestran una alta confiabilidad y concordancia en la estructura
factorial con la versión original, lo que implica adecuada validez de la prueba en población colombiana
de enfermos crónicos.The present study has a psychometric design, with the objective of analyzing the factorial structure and the internal consistency for the Spanish version of the Fatigue Severity Scale (FSS) Questionnaire for Colombian population with chronic disease. Was applied the questionnaire to 52 people with chronic disease in Villavicencio city. The factorial Analysis indicates three factors: Factor 1 named physical affectation, Factor 2 named social affectation and Factor 3 named motivational affectation of the fatigue, where they explain the 76.324% of the total cumulative variance with .870 of Cronbach's Alpha. The results present a high reliability and concordance for the factorial structure with the original version which indicates an adequate validity of the test for Colombian population with chronic disease. © Servicio de Publicaciones - Universidad de Murcia
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