5,206 research outputs found
LHC Phenomenology of Type II Seesaw: Nondegenerate Case
In this paper, we thoroughly investigate the LHC phenomenology of the type II
seesaw mechanism for neutrino masses in the nondegenerate case where the
triplet scalars of various charge () have
different masses. Compared with the degenerate case, the cascade decays of
scalars lead to many new, interesting signal channels. In the positive scenario
where , the four-lepton signal is still
the most promising discovery channel for the doubly-charged scalars
. The five-lepton signal is crucial to probe the mass spectrum of
the scalars, for which, for example, a reach at 14 TeV LHC for
with requires an integrated
luminosity of 76/fb. And the six-lepton signal can be used to probe the neutral
scalars , which are usually hard to detect in the degenerate case. In
the negative scenario where , the
detection of is more challenging, when the cascade decay
is dominant. The most important channel is the
associated production in the final state
, which requires a luminosity of 109/fb
for a discovery, while the final state
is less promising. Moreover, the
associated production can give same signals as the standard model
Higgs pair production. With a much larger cross section, the
production in the final state could reach
significance at 14 TeV LHC with a luminosity of 300/fb. In summary, with an
integrated luminosity of order 500/fb, the triplet scalars can be fully
reconstructed at 14 TeV LHC in the negative scenario.Comment: 41 pages, 20 figures, 7 tables. Version 2 accepted by PRD. 41 pages,
18 figures. Main changes are, (1) rewording in secs III and IV, removing 2
figs and quoting ref [34]; (2) a paragraph added before eq (10) to clarify
constraints from electroweak precision data; (3) a paper added to ref [11].
No changes in result
LHC Phenomenology of the Type II Seesaw Mechanism: Observability of Neutral Scalars in the Nondegenerate Case
This is a sequel to our previous work on LHC phenomenology of the type II
seesaw model in the nondegenerate case. In this work, we further study the pair
and associated production of the neutral scalars H^0/A^0. We restrict ourselves
to the so-called negative scenario characterized by the mass order
M_{H^{\pm\pm}}>M_{H^\pm}>M_{H^0/A^0}, in which the H^0/A^0 production receives
significant enhancement from cascade decays of the charged scalars
H^{\pm\pm},~H^\pm. We consider three important signal
channels---b\bar{b}\gamma\gamma, b\bar{b}\tau^+\tau^-,
---and perform detailed simulations. We find
that at the 14 TeV LHC with an integrated luminosity of 3000/fb, a 5\sigma mass
reach of 151, 150, and 180 GeV, respectively, is possible in the three channels
from the pure Drell-Yan H^0A^0 production, while the cascade-decay-enhanced
H^0/A^0 production can push the mass limit further to 164, 177, and 200 GeV.
The neutral scalars in the negative scenario are thus accessible at LHC run II.Comment: v1: 32 pages, 17 figures, 3 tables. v2: added 2 refs (2nd in [61] and
[66]), revised Acknowledgments, and corrected grammatical errors according to
proofs; no other change
Interpretation of 750 GeV Diphoton Excess at LHC in Singlet Extension of Color-octet Neutrino Mass Model
We propose that the possible 750 GeV diphoton excess can be explained in the
color-octet neutrino mass model extended with a scalar singlet . The
model generally contains species of color-octet, electroweak doublet
scalars and species of color-octet, electroweak triplet or
singlet fermions. While both scalars and fermions contribute to the
production of through gluon fusion, only the charged members induce the
diphoton decay of . The diphoton rate can be significantly enhanced due
to interference between the scalar and fermion loops. We show that the diphoton
cross section can be from 3 to 10 fb for O(TeV) color-octet particles while
evading all current LHC limits.Comment: 12 pages, 4 figures; v2: 13 pages, 4 figures, version to appear in
EPJC, clarified a few things, updated numerical analysis using the most
recent bound on color-octet fermions but without changing conclusions,
corrected a mistake when quoting the branching ratio to Z gamma, added some
references missed in v
Radiative Neutrino Mass with Dark matter: From Relic Density to LHC Signatures
In this work we give a comprehensive analysis on the phenomenology of a
specific dark matter (DM) model in which neutrino mass is
induced at two loops by interactions with a DM particle that can be a complex
scalar or a Dirac fermion. Both the DM properties in relic density and direct
detection and the LHC signatures are examined in great detail, and indirect
detection for gamma-ray excess from the Galactic Center is also discussed
briefly. On the DM side, both semi-annihilation and co-annihilation processes
play a crucial role in alleviating the tension of parameter space between relic
density and direct detection. On the collider side, new decay channels
resulting from particles lead to distinct signals at LHC.
Currently the trilepton signal is expected to give the most stringent bound for
both scalar and fermion DM candidates, and the signatures of fermion DM are
very similar to those of electroweakinos in simplified supersymmetric models.Comment: 40 pages, 24 figure
Robust SLAM and motion segmentation under long-term dynamic large occlusions
Visual sensors are key to robot perception, which can not only help robot localisation but also enable robots to interact with the environment. However, in new environments, robots can fail to distinguish the static and dynamic components in the visual input. Consequently, robots are unable to track objects or localise themselves. Methods often require precise robot proprioception to compensate for camera movement and separate the static background from the visual input. However, robot proprioception, such as \ac{IMU} or wheel odometry, usually faces the problem of drift accumulation. The state-of-the-art methods demonstrate promising performance but either (1) require semantic segmentation, which is inaccessible in unknown environments, or (2) treat dynamic components as outliers -- which is unfeasible when dynamic objects occupy a large proportion of the visual input.
This research work systematically unifies camera and multi-object tracking problems in indoor environments by proposing a multi-motion tracking system; and enables robots to differentiate the static and dynamic components in the visual input with the understanding of their own movements and actions. Detailed evaluation of both simulation environments and robotic platforms suggests that the proposed method outperforms the state-of-the-art dynamic SLAM methods when the majority of the camera view is occluded by multiple unmodeled objects over a long period of time
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