2,467 research outputs found
Inert Doublet Dark Matter with an additional scalar singlet and 125 GeV Higgs Boson
In this work we consider a model for particle dark matter where an extra
inert Higgs doublet and an additional scalar singlet is added to the Standard
Model (SM) Lagrangian. The dark matter candidate is obtained from only the
inert doublet. The stability of this one component dark matter is ensured by
imposing a symmetry on this additional inert doublet. The additional
singlet scalar has a vacuum expectation value (VEV) and mixes with the Standard
Model Higgs doublet resulting in two CP even scalars and . We treat
one of these scalars, , to be consistent with the SM Higgs like boson of
mass around 125 GeV reported by the LHC experiment. These two CP even scalars
affect the annihilation cross-section of this inert doublet dark matter
resulting in a larger dark matter mass region that satisfies the observed relic
density. We also investigate the and processes and compared these with LHC results. This is
also used to constrain the dark matter parameter space in the present model. We
find that the dark matter candidate in the mass region GeV ( GeV, mass of ) satisfies the recent bound from LUX
direct detection experiment.Comment: 21 Pages, 5 Figures, 1 Tabl
Extension of Minimal Fermionic Dark Matter Model : A Study with Two Higgs Doublet Model
We explore a fermionic dark matter model with a possible extension of
Standard Model (SM) of particle physics into two Higgs doublet model. Higgs
doublets couple to the singlet fermionic dark matter (FDM) through a non
renormalisable coupling providing a new physics scale. We explore the viability
of such dark matter candidate and constrain the model parameter space by
collider serach, relic density of DM, direct detection measurements of
DM-nucleon scattreing cross-section and with the experimentally obtained
results from indirect search of dark matter.Comment: 22 pages, 17 new png figures, Title changed, new references added,
major revisio
Low Energy Gamma Ray Excess Confronting a Singlet Scalar Extended Inert Doublet Dark Matter Model
Recent study of gamma rays originating from the region of galactic centre has
confirmed an anomalous -ray excess within the energy range 1-3 GeV.
This can be explained as the consequence of pair annihilation of a 31-40 GeV
dark matter into with thermal annihilation cross-section . In this work we revisit the Inert
Doublet Model (IDM) in order to explain this gamma ray excess. Taking the
lightest inert particle (LIP) as a stable DM candidate we show that a 31-40 GeV
dark matter derived from IDM will fail to satisfy experimental limits on dark
matter direct detection cross-section obtained from ongoing direct detection
experiments and is also inconsistent with LHC findings. We show that a singlet
extended inert doublet model can easily explain the reported -ray
excess which is as well in agreement with Higgs search results at LHC and other
observed results like DM relic density and direct detection constraints.Comment: 17 pages, 4 figure
Possible explanation of indirect gamma ray signatures from hidden sector fermionic dark matter
We propose the existence of a hidden or dark sector besides the standard
model (SM) of particle physics, whose members (both fermionic and bosonic) obey
a local SU(2) gauge symmetry while behaving like a singlet under the
SM gauge group. However, the fermiomic fields of the dark sector also possess
another global U(1) symmetry which remains unbroken. The local
SU(2) invariance of the dark sector is broken spontaneously when a
scalar field in this sector acquires a vacuum expectation value (VEV) and
thereby generating masses to the dark gauge bosons and dark fermions charged
under the SU(2). The lightest fermion in this dark SU(2)
sector can be a potential dark matter candidate. We first examine the viability
of the model and constrain the model parameter space by theoretical constraints
such as vacuum stability and by the experimental constraints such as PLANCK
limit on relic density, LHC data, limits on spin independent scattering
cross-section from dark matter direct search experiments etc. We then
investigate the gamma rays from the pair annihilation of the proposed dark
matter candidate at the Galactic Centre region. We also extend our calculations
of gamma rays flux for the case of dwarf galaxies and compare the signatures of
gamma rays obtained from these astrophysical sites.Comment: 33 pages, 16 figures, title changed, major revisio
Trends in Pattern Recognition and Machine Learning
This paper is tutorial in nature introducing the statistical and syntactic pattern recognition technique. The problem of pattern recognition has special reference with image analysis and some aspects of modern methods and application of the area of shape analysis and detection of objects included
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