2,147 research outputs found
Analysis of the BATSE Continuous MER data
The CGRO/BATSE database includes many types of data such as the 16-channel
continuous background or medium energy resolution burst data (CONT and MER data
types). We have calculated some four hundred burst's medium energy resolution
spectra and Principal Component Analysis has been applied. We found five
components can describe GRBs' spectra.Comment: 4 pages, 2 figures, accepted in Nuovo Ciment
Survival analysis of the optical brightness of GRB host galaxies
We studied the unbiased optical brightness distribution which was calculated
from the survival analysis of host galaxies and its relationship with the Swift
GRB data of the host galaxies observed by the Keck telescopes. Based on the
sample obtained from merging the Swift GRB table and the Keck optical data we
also studied the dependence of this distribution on the data of the GRBs.
Finally, we compared the HGs distribution with standard galaxies distribution
which is in the DEEP2 galaxies catalog.Comment: Swift: 10 Years of Discovery. Conference paper. 2-5 December 2014. La
Sapienza University, Rome, Ital
Intrinsic optical dichroism in the chiral superconducting state of SrRuO
We present an analysis of the Hall conductivity in
time reversal symmetry breaking states of exotic superconductors. We find that
the dichroic signal is non-zero in systems with inter-band order parameters.
This new intrinsic mechanism may explain the Kerr effect observed in strontium
ruthenate and possibly other superconductors. We predict coherence factor
effects in the temperature dependence of the imaginary part of the ac Hall
conductivity , which can be tested experimentally.Comment: 4+ pages, 4 figures, published versio
Comparing the observed properties of the GRBs detected by the Fermi and Swift satellites
We studied the distribution of the GRBs, observed by the Fermi satellite, in
the multidimensional parameter space consisting of the duration, Fluence, Peak
flux and Peak energy (if it was available). About 10% of the Fermi bursts was
observed also by the Swift satellite. We did not find significant differences
between the Peak flux and Peak energy of GRBs observed and not observed also by
the Swift satellite. In contrast, those GRBs detected also by the Swift
satellite had significantly greater Fluence and duration. We did a similar
study for the GRBs detected by the Swift satellite. About 30% percent of these
bursts was also measured by the Fermi satellite. We found a significant
difference in the Fluence, Peak flux and Photon index but none in duration.
These differences may be accounted for the different construction and observing
strategy of the Fermi and Swift satellites.Comment: 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 5 in eConf
Proceedings C130414
Rare-earth impurities in CoMnSi: an opportunity to improve Half-Metallicity at finite temperatures
We analyse the effects of doping Holmium impurities into the full-Heusler
ferromagnetic alloy CoMnSi. Experimental results, as well as theoretical
calculations within Density Functional Theory in the "Local Density
Approximation plus Hubbard U" framework show that the holmium moment is aligned
antiparallely to that of the transition metal atoms. According to the
electronic structure calculations, substituting Ho on Co sites introduces a
finite density of states in the minority spin gap, while substitution on the Mn
sites preserves the half-metallic character.Comment: 22 pages, 8 figures. published in PR
A Comparison of Predictions for SM Higgs Boson Production at the LHC
This paper describes a comparison of most of the available predictions for
the cross section and transverse momentum distribution for a 125 GeV mass Higgs
at the LHC, including those from the PYTHIA and HERWIG parton shower Monte
Carlos and from four resummation calculations.Comment: 7 pages, submitted to proceedings of the Workshop on Physics at TeV
Colliders, Les Houches 200
The Kerr rotation in the unconventional superconductor SrRuO
The interpretation of Kerr rotation measurements in the superconducting phase
of SrRuO is a controversial topic. Both intrinsic and extrinsic
mechanisms have been proposed, and it has been argued that the intrinsic
response vanishes by symmetry. We focus on the intrinsic contribution and
clarify several conflicting results in the literature. On the basis of symmetry
considerations and detailed calculations we show that the intrinsic Kerr signal
is not forbidden in a general multi- band system but has a rich structure in
the near infrared regime. We distinguish different optical transitions
determined by the superconducting gap (far infrared) and the inter orbital
coupling of the normal state (near infrared). We argue that the low frequency
transitions do not contribute to the Hall conductivity while only the
inter-orbital transitions in the near infrared regime contribute. Finally, we
discuss the difficulties to connect the calculations for the optical Hall
conductivity to the experimental measurement of the Kerr angle. We will compare
different approximations which might lead to conflicting results.Comment: 9 pages, 8 figures, 1 tabl
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