548 research outputs found
Leptophilic dark matter in gauged model in light of DAMPE cosmic ray excess
Motivated by the very recent cosmic-ray electron+positron excess observed by
DAMPE collaboration, we investigate a Dirac fermion dark matter (DM) in the
gauged model. DM interacts with the electron and muon via the
gauge boson . The model can explain the DAMPE data well.
Although a non-zero DM-nucleon cross section is only generated at one loop
level and there is a partial cancellation between and
couplings, we find that a large portion of mass is ruled out from
direct DM detection limit leaving the allowed mass to be close to two
times of the DM mass. Implications for and , and muon anomaly are also studied.Comment: Discussions added, version accepted by EPJ
Vacuum stability in stau-neutralino coannihilation in MSSM
The stau-neutralino coannihilation provides a feasible way to accommodate the
observed cosmological dark matter (DM) relic density in the minimal
supersymmetric standard model (MSSM). In such a coannihilation mechanism the
stau mass usually has an upper bound since its annihilation rate becomes small
with the increase of DM mass. Inspired by this observation, we examine the
upper limit of stau mass in the parameter space with a large mixing of staus.
We find that the stau pair may dominantly annihilate into dibosons and hence
the upper bound on the stau mass ( GeV) obtained from the
final states can be relaxed. Imposing the DM relic density constraint and
requiring a long lifetime of the present vacuum, we find that the lighter stau
mass can be as heavy as about 1.4 TeV for the stau maximum mixing. However, if
requiring the present vacuum to survive during the thermal history of the
universe, this mass limit will reduce to about 0.9 TeV. We also discuss the
complementarity of vacuum stability and direct detections in probing this stau
coannihilation scenario.Comment: 12 pages, 6 figure
A minimal extension of MSSM in light of the B decay anomaly
Motivated by the and anomalies from B decays, we extend the
minimal supersymmetric model with a non-universal anomaly-free
gauge symmetry, coupling non-universally to the lepton sector as well as the
quark sector. In particular, only the third generation quarks are charged under
this , which can easily evade the dilepton bound from the LHC
searches. An extra singlet is introduced to break this symmetry
allowing for the -term to be generated dynamically. The relevant
constraints of mixing, mixing and the LHC
dilepton searches are considered. We find that in the allowed parameter space
this gauge interaction can accommodate the and
anomalies and weaken considerably the mass limits while remaining
perturbative up to the Planck scale.Comment: 12 pages,2 figure
Probing GeV-scale MSSM neutralino dark matter in collider and direct detection experiments
Given the recent constraints from the dark matter (DM) direct detections, we
examine a light GeV-scale (2-30 GeV) neutralino DM in the alignment limit of
the Minimal Supersymmetric Standard Model (MSSM). In this limit without
decoupling, the heavy CP-even scalar plays the role of the Standard Model
(SM) Higgs boson while the other scalar can be rather light so that the DM
can annihilate through the resonance or into a pair of to achieve the
observed relic density. With the current collider and cosmological constraints,
we find that such a light neutralino DM above 6 GeV can be excluded by the
XENON-1T (2017) limits while the survivied parameter space below 6 GeV can be
fully covered by the future germanium-based light dark matter detections (such
as CDEX), by the Higgs coupling precison measurements or by the production
process at an electron-positron collider (Higgs factory).Comment: 15 pages, 5 figures. Discussions and references added, version
accepted by PL
Simplified TeV leptophilic dark matter in light of DAMPE data
Using a simplified framework, we attempt to explain the recent DAMPE cosmic
flux excess by leptophilic Dirac fermion dark matter (LDM). The
scalar () and vector () mediator fields connecting LDM and
Standard Model particles are discussed. Under constraints of DM relic density,
gamma-rays, cosmic-rays and Cosmic Microwave Background (CMB), we find that the
couplings , , and can
produce the right bump in flux for a DM mass around 1.5 TeV with a
natural thermal annihilation cross-section today. Among them, coupling is tightly constrained by
PandaX-II data (although LDM-nucleus scattering appears at one-loop level) and
the surviving samples appear in the resonant region, . We also study the related collider signatures, such as dilepton
production , and muon anomaly. Finally,
we present a possible realization for such leptophilic dark matter.Comment: discussions added, version accepted by JHE
Language Embedded 3D Gaussians for Open-Vocabulary Scene Understanding
Open-vocabulary querying in 3D space is challenging but essential for scene
understanding tasks such as object localization and segmentation.
Language-embedded scene representations have made progress by incorporating
language features into 3D spaces. However, their efficacy heavily depends on
neural networks that are resource-intensive in training and rendering. Although
recent 3D Gaussians offer efficient and high-quality novel view synthesis,
directly embedding language features in them leads to prohibitive memory usage
and decreased performance. In this work, we introduce Language Embedded 3D
Gaussians, a novel scene representation for open-vocabulary query tasks.
Instead of embedding high-dimensional raw semantic features on 3D Gaussians, we
propose a dedicated quantization scheme that drastically alleviates the memory
requirement, and a novel embedding procedure that achieves smoother yet high
accuracy query, countering the multi-view feature inconsistencies and the
high-frequency inductive bias in point-based representations. Our comprehensive
experiments show that our representation achieves the best visual quality and
language querying accuracy across current language-embedded representations,
while maintaining real-time rendering frame rates on a single desktop GPU
rac-(1R,2S,6R,7R)-4-{[(1E)-(2-ChloroÂphenÂyl)methylÂidene]amino}-1-isopropyl-7-methyl-4-azaÂtricycloÂ[5.2.2.02,6]undec-8-ene-3,5-dione
The title compound, C21H23ClN2O2, was synthesized from N-amino-α-terpinene maleimide and 2-chloroÂbenzaldehyde. There are two independent molÂecules in the asymmetric unit which are linked via an interÂmolecular C—H⋯O hydrogen bond. The crystal studied was found to be a partial merohedral twin, with a 0.74 (7):0.26 (7) domain ratio
Involvement of protein kinase C-δ activation in betulininduced apoptosis of neuroblastoma
Purpose: To investigate the clinical benefits and underlying mechanisms of action of betulin in the treatment of cancer using a neuroblastoma (NB) cell model.Method: Cell viability assay (MTT assay) was applied to investigate the effects of betulin on proliferation and apoptosis of SK-N-SH cell. The expression or translocation of apoptosis-related biomarkers, which include protein kinase C (PKC) family members, were analyzed and quantified by Western blotting, caspase activity assay or enzyme-linked immunosorbent assay (ELISA).Results: Betulin treatment significantly inhibited the growth of SK-N-SH cells (p < 0.001), with halfmaximal inhibition concentration (IC50) of 8 μmol/mL. Furthermore, betulin treatment increased the activity of PKC-δ, which subsequently activated caspases 3, 8 and 9, thus initiating mitochondriamediated endogenous apoptotic pathways in SK-N-SH cellsConclusion: Data generated in this study suggest that betulin inhibits cell proliferation and promotes apoptosis via PKC-δ activation, which may provide new insights into NB treatment from the perspective of adjuvant chemotherapy and prevention of tumor recurrence.Keywords: Betulin, Neuroblastoma, Apoptosis, protein kinase C-δ, Adjuvant chemotherapy, Tumor recurrence, Caspas
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