Cluster X-ray line at 3.5 keV3.5\,{\rm keV} from axion-like dark matter

The recently reported X-ray line signal at $E_\gamma \simeq 3.5\, {\rm keV}$ from a stacked spectrum of various galaxy clusters and the Andromeda galaxy may be originating from a decaying dark matter particle of the mass $2 E_\gamma$. A light axion-like scalar is suggested as a natural candidate for dark matter and its production mechanisms are closely examined. We show that the right amount of axion relic density with the preferred parameters, $m_a \simeq 7 \,{\rm keV}$ and $f_a \simeq 4\times 10^{14}\, {\rm GeV}$, can be naturally obtainable from the decay of inflaton. If the axions were produced from the saxion decay, it could not have constituted the total relic density due to the bound from structure formation. Nonetheless, the saxion decay is an interesting possibility, because the $3.5\, {\rm keV}$ line and dark radiation can be addressed simultaneously, being consistent with the Planck data. Small misalignment angles of the axion, ranging between $\theta_a\sim 10^{-4} -10^{-1}$ depending on the reheating temperature, can also be the source of axion production. The model with axion misalignment can satisfy the constraints for structure formation and iso-curvature perturbation.Comment: 14 pages, significant changes in the form, matched to the journal versio

Fermi Gamma Ray Line at 130 GeV from Axion-Mediated Dark Matter

We consider a singlet Dirac fermion with Peccei-Quinn(PQ) symmetry as dark matter. A singlet complex scalar is introduced to mediate between dark matter and the SM through Higgs portal interaction and electroweak PQ anomalies. We show that a resonant annihilation of dark matter with axion mediation can explain the monochromatic photon line of the Fermi LAT data at 130 GeV by anomaly interactions while the annihilation cross section with Higgs portal interaction is p-wave suppressed. We discuss the interplay between the direct detection of the fermion dark matter and the collider search of Higgs-like scalars. We also present a ultra-violet completion of the dark matter model into the NMSSM with PQ symmetry.Comment: 22 pages, 9 figures, To be published in Phys. Rev.

EXPLORATIVE STUDY ON THE CYBER-ATTACK SOURCE TRACEBACK TECHNOLOGIES FOR BRIGHT INTERNET

In order to cope with the various types of cyber-attacks in the Internet, several methods of tracking the source of attack have been developed. However, until recently, most of them are defensive security methods rather than preventive one. In order to settle the Bright Internet, which is still in its early stage, it is necessary to establish a technical source tracking method. For this, a standard and evaluation criteria are needed to determine which technology would be appropriate for the Bright Internet requirements. In this paper, we classify cyber-attack source traceback technologies and derive some criteria for the evaluation of the technologies for the Bright Internet. Using the criteria, we can evaluate existing traceback technologies from the perspective of the Bright Internet. In this article, we try to evaluate SAVA, PPM, iTrace, Controlled flooding, Input Debugging, Central Track, IPSec, SPIE(Hash-based), and Marking+Logging methods. Based on this research, future research will require in-depth verification of traceback technologies that reflects all the principles of the Bright Internet in practice

Soft Tissue Surgery for Equinus Deformity in Spastic Hemiplegic Cerebral Palsy: Effects on Kinematic and Kinetic Parameters

The purpose of this study was to evaluate how soft tissue surgery for correcting equinus deformity affects the kinematic and kinetic parameters of the ankle and proximal joints. Sixteen children with spastic hemiplegic cerebral palsy and equinus deformities (age range 3-16 years) were included. Soft tissue surgeries were performed exclusively on the ankle joint area in all subjects. Using computerized gait analysis (Vicon 370 Motion Analysis System), the kinematic and kinetic parameters during barefoot ambulation were collected preoperatively and postoperatively. In all 16 children, the abnormally increased ankle plantar flexion and pelvis anterior tilting on the sagittal plane were significantly improved without a weakening of push-off (p < 0.05). In a group of 8 subjects with a recurvatum knee gait pattern before operation, the postoperative kinematic and kinetic parameters of the knee joint were significantly improved (p < 0.05). In a group of 8 subjects with ipsilateral pelvic external rotation before operation, the postoperative pelvic deviations on the transverse plane were significantly decreased (p < 0.05). These findings suggest that the soft tissue surgery for correcting equinus deformity improves not only the abnormal gait pattern of the ankle, but also that of the knee and pelvis

Numerical Analysis of Flow Characteristics in Confulent Channels

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv