11,035 research outputs found
Properties of spectrally-defined red QSOs at z = 0.3-1.2
We investigated the properties of a sample of red Quasi-stellar Objects
(QSOs) using optical, radio, and infrared data. These QSOs were selected from
the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) quasar catalog. We only
selected sources with sky coverage of the Very Large Array Faint Images of the
Radio Sky at Twenty-centimeters (VLA FIRST) survey, and searched for sources
with Wide-field Infrared Survey Explorer (WISE) counterparts. We defined the
spectral color of the QSOs based on the flux ratio of the rest frame 4000
to 3000 continuum emission to select red QSOs and typical QSOs. In
accordance with this criterion, only QSOs with redshifts between 0.3 and 1.2
could be selected. We found that the red QSOs have stronger infrared emission
than the typical QSOs do. We noted that the number ratios of the red QSOs to
the typical QSOs decrease with increasing redshifts, although the number of the
typical QSOs increase with redshifts. Furthermore, at high redshifts, the
luminosity distributions of the typical QSOs and the red QSOs seem to have
similar luminosity distribution peaks; however, at low redshifts, the
luminosities of the red QSOs seem to be lower than those of the typical QSOs.
These findings suggest that there might be at least two types of red QSOs in
our QSO samples.Comment: 12 pages, 11 figures, 9 tables, ApJ accepte
An Updated Analysis of Inert Higgs Doublet Model in light of the Recent Results from LUX, PLANCK, AMS-02 and LHC
In light of the recent discovery by the ATLAS and CMS experiments at the
Large Hadron Collider (LHC) of a Higgs-like particle with a narrow mass range
of 125-126 GeV, we perform an updated analysis on one of the popular scalar
dark matter models, the Inert Higgs Doublet Model (IHDM). We take into account
in our likelihood analysis of various experimental constraints, including
recent relic density measurement, dark matter direct and indirect detection
constraints as well as the latest collider constraints on the invisible decay
width of the Higgs boson and monojet search at the LHC. It is shown that if the
invisible decay of the standard model Higgs boson is open, LHC as well as
direct detection experiments like LUX and XENON100 could put stringent limits
on the Higgs boson couplings to dark matter. We find that the most favoured
parameter space for IHDM corresponds to dark matter with a mass less than 100
GeV or so. In particular, the best-fit points are at the dark matter mass
around 70 GeV where the invisible Higgs decay to dark matter is closed. Scalar
dark matter in the higher mass range of 0.5-4 TeV is also explored in our
study. Projected sensitivities for the future experiments of monojet at LHC-14,
XENON1T and AMS-02 one year antiproton flux are shown to put further
constraints on the existing parameter space of IHDM.Comment: Matches JCAP accepted version, 49 pages, 27 figure
Annealed MAP
Maximum a Posteriori assignment (MAP) is the problem of finding the most
probable instantiation of a set of variables given the partial evidence on the
other variables in a Bayesian network. MAP has been shown to be a NP-hard
problem [22], even for constrained networks, such as polytrees [18]. Hence,
previous approaches often fail to yield any results for MAP problems in large
complex Bayesian networks. To address this problem, we propose AnnealedMAP
algorithm, a simulated annealing-based MAP algorithm. The AnnealedMAP algorithm
simulates a non-homogeneous Markov chain whose invariant function is a
probability density that concentrates itself on the modes of the target
density. We tested this algorithm on several real Bayesian networks. The
results show that, while maintaining good quality of the MAP solutions, the
AnnealedMAP algorithm is also able to solve many problems that are beyond the
reach of previous approaches.Comment: Appears in Proceedings of the Twentieth Conference on Uncertainty in
Artificial Intelligence (UAI2004
A generic method to constrain the dark matter model parameters from Fermi observations of dwarf spheroids
Observation of gamma-rays from dwarf galaxies is an effective way to search
for particle dark matter. Using 4-year data of Fermi-LAT observations on a
series of Milky Way satellites, we develop a general way to search for the
signals from dark matter annihilation in such objects. Instead of giving prior
information about the energy spectrum of dark matter annihilation, we bin the
Fermi-LAT data into several energy bins and build a likelihood map in the
"energy bin - flux" plane. The final likelihood of any spectrum can be easily
derived through combining the likelihood of all the energy bins. It gives
consistent result with that directly calculated using the Fermi Scientific
Tool. This method is very efficient for the study of any specific dark matter
models with gamma-rays. We use the new likelihood map with Fermi-LAT 4 year
data to fit the parameter space in three representative dark matter models: i)
toy dark matter model, ii) effective dark matter operators, and iii)
supersymmetric neutralino dark matter.Comment: Matches JCAP accepted version, 8 pages, 6 figure
LikeDM: likelihood calculator of dark matter detection
With the large progress in searches for dark matter (DM) particles with
indirect and direct methods, we develop a numerical tool that enables fast
calculations of the likelihoods of specified DM particle models given a number
of observational data, such as charged cosmic rays from space-borne experiments
(e.g., PAMELA, AMS-02), gamma-rays from the Fermi space telescope, and
underground direct detection experiments. The purpose of this tool --- LikeDM,
likelihood calculator for dark matter detection --- is to bridge the gap
between a particle model of DM and the observational data. The intermediate
steps between these two, including the astrophysical backgrounds, the
propagation of charged particles, the analysis of Fermi gamma-ray data, as well
as the DM velocity distribution and the nuclear form factor, have been dealt
with in the code. We release the first version (v1.0) focusing on the
constraints from indirect detection of DM with charged cosmic and gamma rays.
Direct detection will be implemented in the next version. This manual describes
the framework, usage, and related physics of the code. The code LikeDM can be
download from https://likedm.hepforge.org/Comment: v2, published in Computer Physics Communications, "LikeDM can be
download from https://likedm.hepforge.org/
Block Shelves for Visual Programming Languages
The blocks editor, such as the editor in Scratch, is widely applied for
visual programming languages (VPL) nowadays. Despite it's friendly for
non-programmers, it exists three main limitations while displaying block codes:
(1) the readability, (2) the program structure, and (3) the re-use. To cope
with these issues, we introduce a novel formatting tool, block shelves, into
the editor for organizing blocks. A user could utilize shelves to constitute a
user-defined structure for the VPL projects. Based on the experiment results,
block shelves improves the block code navigating and searching significantly.
Besides, for achieving code re-use, users could use shelf export/import to
share/re-use their block codes between projects in the file format of
eXtensible Markup Language (xml.) All functions were demonstrated on MIT App
inventor 2, while all modifications were made in Google Blockly.Comment: 6 pages, 6 figures, short pape
The sorting index on colored permutations and even-signed permutations
We define a new statistic on the set of colored permutations
and prove that it has the same distribution as the length
function. For the set of restricted colored permutations corresponding to the
arrangements of non-attacking rooks on a fixed Ferrers shape we show that
the following two sequences of set-valued statistics are joint equidistributed:
,
,
,
and
,
,
,
. Analogous results
are also obtained for Coxeter group of type . Our results extend recent
results of Petersen, Chen-Gong-Guo and Poznanovi\'{c}.Comment: 28 pages, 2 figures. Some typos are corrected in this versio
Set-valued sorting index and joint equidistributions
Recently Petersen defined a new Mahonian index sor over the symmetric group
and proved that and have the same joint distribution. Foata and Han proved that the
pairs of set-valued statistics have the same joint distribution over
.
In this paper we introduce the set-valued statistics and and generalize simultaneously
results of Petersen and Foata-Han and find many equidistributed triples of
set-valued statistics and quadruples of statistics.Comment: 12 pages, 1 figur
Toric -polynomials of hook shape lattice Path Matroid Polytopes and product of simplices
It is known that a lattice path matroid polytope can be associated with two
given noncrossing lattice paths on with the same
end points. In this short note we give explicit formulae for the -vector,
toric - and -polynomials of a lattice path matroid polytope when two
boundary paths enclose a hook shape.Comment: 15 pages, 3 figure
G2HDM : Gauged Two Higgs Doublet Model
A novel model embedding the two Higgs doublets in the popular two Higgs
doublet models into a doublet of a non-abelian gauge group is
presented. The Standard Model right-handed fermion singlets are
paired up with new heavy fermions to form doublets, while
left-handed fermion doublets are singlets under . Distinctive features
of this anomaly-free model are: (1) Electroweak symmetry breaking is induced
from spontaneous symmetry breaking of via its triplet vacuum
expectation value; (2) One of the Higgs doublet can be inert, with its neutral
component being a dark matter candidate as protected by the gauge
symmetry instead of a discrete symmetry in the usual case; (3) Unlike
Left-Right Symmetric Models, the complex gauge fields (along with other complex scalar fields) associated with the
do {\it not} carry electric charges, while the third component
can mix with the hypercharge gauge field and the third
component of ; (4) Absence of tree level flavour changing neutral
current is guaranteed by gauge symmetry; and {\it etc}. In this work, we
concentrate on the mass spectra of scalar and gauge bosons in the model.
Constraints from previous data at LEP and the Large Hadron Collider
measurements of the Standard Model Higgs mass, its partial widths of
and modes are discussed.Comment: 40 pages, 7 figures, version accepted in JHEP, relic density
discussion adde
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