85 research outputs found
Fractional chaotic inflation in the lights of PLANCK and BICEP2
In the lights of current BICEP2 observations accompanied with the PLANCK
satellite results, it has been observed that the simple single field chaotic
inflationary models provide a good agreement with their spectral index n_s and
large tensor-to-scalar ratio r (0.15 <r <0.26). To explore the other simple
models, we consider the fractional-chaotic inflationary potentials of the form
V_0 phi^(a/b) where a and b are relatively prime. We show that such kind of
inflaton potentials can be realized elegantly in the supergravity framework
with generalized shift symmetry and a nature bound a/b < 4 for consistency.
Especially, for the number of e-folding from 50 to 60 and some a/b from 2 to 3,
our predictions are nicely within at least 1 region in the r-n_s
plane. We also present a systematic investigation of such chaotic inflationary
models with fractional exponents to explore the possibilities for the
enhancement in the magnitude of running of spectral index (\alpha_{n_s}) beyond
the simplistic models.Comment: 16 pages, 5 figures, references added, published in PL
Interpretation of the diphoton excess at CMS and ATLAS
We consider the diphoton resonance at the 13 TeV LHC in a consistent model
with new scalars and vector-like fermions added to the Standard Model (SM),
which can be constructed from orbifold grand unified theories and string
models. The gauge coupling unification can be achieved, neutrino masses can be
generated radiatively, and electroweak vacuum stability problem can be solved.
To explain the diphoton resonance, we study a spin-0 particle, and discuss
various associated final states.Comment: 8 pages, 6 figures, 3 tables; v2: typos corrected, references adde
The Leptoquark Implication from the CMS and IceCube Experiments
The recent excess in the CMS measurements of and channels
and the emergence of PeV comsic neutrino events at the IceCube experiment share
an intriguing implication for a leptoquark with a 600-650 GeV mass. We
investigate the CMS constraints on the flavor structure of a scenario with the
minimal leptoquark Yukawa couplings and correlate such a scenario to the
resonant enhancement in the very high energy shower event rates at the IceCube.
We find for a single leptoquark, the CMS signals require large couplings to the
third generation leptons. This leads to an enhancement in the
-nucleon scattering cross-section and subsequently more
events at PeV energies. However, a visible enhancement above the Standard Model
scattering would require a leptoquark Yukawa coupling larger than one that can
be easily tested at the upcoming LHC runs.Comment: PRD version. Meson decay constraints and additional citations are
added. 6 pages, 2 figures, 1 tabl
The Minimal UV-induced Effective QCD Axion Theory
The characteristic axion couplings could be generated via effective couplings
between the Standard Model (SM) fermions to a pseudo-Goldstone from a
high-scale Peccei-Quinn (PQ) symmetry breaking. Assuming that the
UV-induced effective operators generate necessary couplings before the PQ
symmetry breaking, and any low-scale couplings to the SM are restricted to the
Yukawa sector, three minimal natural scenarios can be formulated, which
provides a connection between the QCD-axions and mediators at the GUT/string
scales. We find that the PQ symmetry breaking scale could be about
GeV, higher than the classical QCD dark matter axion window but possible if the
anthropic window is considered. We also propose an experiment to probe such
scenarios. If the dark matter axion is discovered, they might suggest that we
live in an atypical Hubble volume.Comment: 4 page
Coarse-to-Fine Amodal Segmentation with Shape Prior
Amodal object segmentation is a challenging task that involves segmenting
both visible and occluded parts of an object. In this paper, we propose a novel
approach, called Coarse-to-Fine Segmentation (C2F-Seg), that addresses this
problem by progressively modeling the amodal segmentation. C2F-Seg initially
reduces the learning space from the pixel-level image space to the
vector-quantized latent space. This enables us to better handle long-range
dependencies and learn a coarse-grained amodal segment from visual features and
visible segments. However, this latent space lacks detailed information about
the object, which makes it difficult to provide a precise segmentation
directly. To address this issue, we propose a convolution refine module to
inject fine-grained information and provide a more precise amodal object
segmentation based on visual features and coarse-predicted segmentation. To
help the studies of amodal object segmentation, we create a synthetic amodal
dataset, named as MOViD-Amodal (MOViD-A), which can be used for both image and
video amodal object segmentation. We extensively evaluate our model on two
benchmark datasets: KINS and COCO-A. Our empirical results demonstrate the
superiority of C2F-Seg. Moreover, we exhibit the potential of our approach for
video amodal object segmentation tasks on FISHBOWL and our proposed MOViD-A.
Project page at: http://jianxgao.github.io/C2F-Seg.Comment: Accepted to ICCV 202
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