Diphoton decay for a 750750 GeV scalar boson in an U(1)XU(1)_{X} model

In the context of a nonuniversal and anomaly free $U(1)_{X}$ extension of the standard model, we examine the decay of a $750$GeV scalar singlet state, $\xi_{\chi}$, 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 $[900,\,3000]$ GeV, a production cross section $\sigma(pp\to\xi_{\chi}\to\gamma\gamma)$ compatible with ATLAS and CMS collaborations data. We also include another scalar singlet, $\sigma$, 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 SU(6)⊗U(1)XSU(6)\otimes U(1)_{X} model

We propose a new $SU(6)\otimes U(1)_{X}$ 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 $\gamma\gamma$ 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 $SU(6)\otimes U(1)_{X}$ 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 $B-L$ 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 $B-L$ asymmetry in a scenario of a concrete $A_4$ 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$_{FM}$) / Cu (5nm) [/ Pt (2nm)] / Al(2nm) heterostructures, FM = \{ Ni$_{81}$Fe$_{19}$, Co$_{60}$Fe$_{20}$B$_{20}$, pure Co\}. Common behavior is observed for three FM layers, where the additional relaxation obeys both a strict inverse power law dependence $\Delta G =K \:t^{n}$, $n=-\textrm{1.04}\pm\textrm{0.06}$ and a similar magnitude $K=\textrm{224}\pm\textrm{40 Mhz}\cdot\textrm{nm}$. As the tested FM layers span an order of magnitude in spin diffusion length $\lambda_{SDL}$, 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 física, 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