8,217 research outputs found
Co-genesis of Matter and Dark Matter with Vector-like Fourth Generation Leptons
We propose a simple extension of the standard model by adding a fourth
generation vector-like lepton doublet and show that if the fourth neutrino is a
massive pseudo-Dirac fermion with mass in the few hundred GeV range and mass
splitting of about 100 keV, its lighter component can be a viable inelastic
dark matter candidate. Its relic abundance is produced by the CP violating
out-of-equilibrium decay of the type-II seesaw scalar triplet, which also gives
rise to the required baryon asymmetry of the Universe via type-II leptogenesis,
thus providing a simultaneous explanation of dark matter and baryon abundance
observed today. Moreover, the induced vacuum expectation value of the same
scalar triplet is responsible for the sub-eV Majorana masses to the three
active neutrinos. A stable fourth generation of neutrinos is elusive at
collider, however might be detected by current dark matter direct search
experiments.Comment: 7 pages, 5 figures and small corrections to match the version
accepted for publication in Physics Letters
Detection of hidden structures on all scales in amorphous materials and complex physical systems: basic notions and applications to networks, lattice systems, and glasses
Recent decades have seen the discovery of numerous complex materials. At the
root of the complexity underlying many of these materials lies a large number
of possible contending atomic- and larger-scale configurations and the
intricate correlations between their constituents. For a detailed
understanding, there is a need for tools that enable the detection of pertinent
structures on all spatial and temporal scales. Towards this end, we suggest a
new method by invoking ideas from network analysis and information theory. Our
method efficiently identifies basic unit cells and topological defects in
systems with low disorder and may analyze general amorphous structures to
identify candidate natural structures where a clear definition of order is
lacking. This general unbiased detection of physical structure does not require
a guess as to which of the system properties should be deemed as important and
may constitute a natural point of departure for further analysis. The method
applies to both static and dynamic systems.Comment: (23 pages, 9 figures
One year of monitoring of the Type IIb supernova SN 2011dh
Optical photometry and low resolution spectroscopy of the type IIb
supernova SN 2011dh in M51 are presented, covering the first year after the
explosion. The light curve and spectral evolution are discussed. The early
phase light curve evolution of SN 2011dh is very similar to SN 1993J and SN
2008ax. In the late phase, however, SN 2011dh declines faster than SN 1993J.
The late phase decline in the -band is steeper than in the and
bands, indicating the possibility of dust formation. With a peak -band
absolute magnitude of mag, SN 2011dh is a marginally
faint type IIb event. The reddening corrected colour curves of SN 2011dh are
found to be redder than other well studied type IIb supernovae. The bolometric
light curve indicates 0.09 M of Ni is synthesized during
the explosion. The HeI lines were detected in the spectra during the rise to
maximum. The nebular spectra of SN 2011dh show a box shaped emission in the red
wing of the [OI] 6300-6363 \AA\ feature, that is attributed to H
emission from a shock excited circumstellar material. The analysis of nebular
spectra indicates that M of oxygen was ejected during the
explosion. Further, the [CaII]/[OI] line ratio in the nebular phase is
0.7, indicating a progenitor with a main sequence mass of 10-15 M.Comment: Accepted for publication in MNRA
Automatic Pill Reminder for Easy Supervision
In this paper we present a working model of an automatic pill reminder and
dispenser setup that can alleviate irregularities in taking prescribed dosage
of medicines at the right time dictated by the medical practitioner and switch
from approaches predominantly dependent on human memory to automation with
negligible supervision, thus relieving persons from error-prone tasks of giving
wrong medicine at the wrong time in the wrong amount.Comment: 5 pages, 7 figures, ICISS- 2017 (IEEE Conference
Pump power reduction by photodarkening in Yb-doped fibres
The influence of the photodarkening at a pump wavelength to envisage the direct impact of the photodarkening in the YDF based devices is reported. Results suggest that the photodarkening does not only induce excess background loss as commonly interpreted, but also influences pump efficiency
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