Electro-Weak Dark Matter: non-perturbative effect confronting indirect detections

We update indirect constraints on Electro-Weak Dark Matter (EWDM) considering the Sommerfeld-Ramsauer-Townsend (SRT) effect for its annihilations into a pair of standard model gauge bosons assuming that EWDM accounts for the observed dark matter (DM) relic density for a given DM mass and mass gaps among the multiplet components. For the radiative or smaller mass splitting, the hypercharged triplet and higher multiplet EWDMs are ruled out up to the DM mass ~ 10 - 20 TeV by the combination of the most recent data from AMS-02 (antiproton), Fermi-LAT (gamma-ray), and HESS (gamma-line). The Majorana triplet (wino-like) EWDM can evade all the indirect constraints only around Ramsauer-Townsend dips which can occur for a tiny mass splitting of order 10 MeV or less. In the case of the doublet (Higgsino-like) EWDM, a wide range of its mass > 500 GeV is allowed except Sommerfeld peak regions. Such a stringent limit on the triplet DM can be evaded by employing a larger mass gap of the order of 10 GeV which allows its mass larger than about 1 TeV. However, the future CTA experiment will be able to cover most of the unconstrained parameter space.Comment: 17 pages, 4 figures; result for an O(10 GeV) mass gap, future sensitivity of CTA, and references adde

A FUNDAMENTAL STUDY ON MEASUREMENT OF HULL ROUGHNESS

In this study, an investigation on the hull roughness measurement of a new ship, a 160m class car ferry, was performed. The hull roughness measurement was conducted in the ferry’s pre-coated state before launching. For measurement, the TQC manual and ITTC recommendations were considered, and measurements were made in a total of 230 zones below waterline of the ship. Accordingly, the average hull roughness of the car ferry was 81μm, which is relatively low compared to 150μm, the hull roughness of a new ship proposed by the ITTC. In addition, the measurement uncertainty was calculated using the ISO guidelines, and the effect of the number of zones on the hull roughness measurement was examined. Using the measured average hull roughness, we estimated the resistance performance at the design speed of the ship. Accordingly, it was confirmed that the total resistance of the new ship was reduced by approximately 2% owing to a decrease in its frictional resistance increase

From motes to Java stamps: smart sensor network testbeds

technical reportWe have proposed Smart Sensor Networks (S-Nets) as an architecture and set of distributed algorithms to extract, interpret and exploit networked sensor devices. Heretofore, the development of this approach has been done in simulation. In this paper, we describe two complementary implementations of S-Nets: (1) on a set of Berkeley motes comprised of low-power 8-bit, 128Kb memory processors, communication devices and sensors, and (2) on a set of JStamps having 32-bit controllers, 2Mb of memory and native execution Java hardware