Leptophilic dark matter in gauged U(1)Le−LμU(1)_{L_e-L_\mu} model in light of DAMPE cosmic ray e++e−e^+ + e^- 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 $L_e - L_\mu$ model. DM interacts with the electron and muon via the $U(1)_{e-\mu}$ gauge boson $Z^{'}$. 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 $Z^{'}ee$ and $Z^{'}\mu\mu$ couplings, we find that a large portion of $Z^{'}$ mass is ruled out from direct DM detection limit leaving the allowed $Z^{'}$ mass to be close to two times of the DM mass. Implications for $pp \to Z^{'} \to 2\ell$ and $pp \to 2\ell + Z^{'}$ , and muon $g-2$ 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 ($\sim400$ GeV) obtained from the $f\bar{f}$ 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 U(1)′U(1)^\prime extension of MSSM in light of the B decay anomaly

Motivated by the $R_K$ and $R_{K^*}$ anomalies from B decays, we extend the minimal supersymmetric model with a non-universal anomaly-free $U(1)^\prime$ 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 $U(1)^\prime$, which can easily evade the dilepton bound from the LHC searches. An extra singlet is introduced to break this $U(1)^\prime$ symmetry allowing for the $\mu$-term to be generated dynamically. The relevant constraints of $B_s-\bar{B}_s$ mixing, $D^0-\bar{D}^0$ mixing and the LHC dilepton searches are considered. We find that in the allowed parameter space this $U(1)^\prime$ gauge interaction can accommodate the $R_K$ and $R_{K^*}$ anomalies and weaken considerably the $Z^\prime$ 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 $H$ plays the role of the Standard Model (SM) Higgs boson while the other scalar $h$ can be rather light so that the DM can annihilate through the $h$ resonance or into a pair of $h$ 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 $e^+e^- \to hA$ 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 $e^+ + e^-$ flux excess by leptophilic Dirac fermion dark matter (LDM). The scalar ($\Phi_0$) and vector ($\Phi_1$) 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 $P \otimes S$, $P \otimes P$, $V \otimes A$ and $V \otimes V$ can produce the right bump in $e^+ + e^-$ flux for a DM mass around 1.5 TeV with a natural thermal annihilation cross-section $\sim 3 \times 10^{-26} cm^3/s$ today. Among them, $V \otimes V$ 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, $m_{\Phi_1} \simeq 2m_{\chi}$. We also study the related collider signatures, such as dilepton production $pp \to \Phi_1 \to \ell^+\ell^-$, and muon $g-2$ anomaly. Finally, we present a possible $U(1)_X$ 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-Chloro­phen­yl)methyl­idene]amino}-1-isopropyl-7-methyl-4-aza­tricyclo­[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-chloro­benzaldehyde. There are two independent mol­ecules in the asymmetric unit which are linked via an inter­molecular 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