Discriminating Minimal SUGRA and Minimal Gauge Mediation Models at the Early LHC

Among various supersymmetric (SUSY) standard models, the gravity mediation model with a neutralino LSP and the gauge mediation model with a very light gravitino are attractive from the cosmological view point. These models have different scales of SUSY breaking and their underlying physics in high energy is quite different. However, if the sparticles' decay into the gravitino is prompt in the latter case, their collider signatures can be similar: multiple jets and missing transverse momentum. In this paper, we study the discrimination between these models in minimal cases at the LHC based on the method using the significance variables in several different modes and show the discrimination is possible at a very early stage after the discovery.Comment: 29 pages, 3 figures, captions improved, typos corrected, appendix added, version published in JHE

位相シフト干渉法による物体周りの対流熱伝達の時空間分布計測

要約のみTohoku University圓山重直課

Design and construction of multi-cylinder type liquid piston Stirling engine

In a multi-cylinder type liquid piston Stirling engine (MCLPSE), liquid columns in U-shaped tubes play the role of solid pistons in a mechanical Stirling engine. Besides the straightforward structure, advantages of the MCLPSE are a relatively low operation temperature difference below 100 K and use of harmless working fluids of air and water. This study presents a mass spring model for the MCLPSE, from which we determine geometrical parameters of MCLPSE to achieve a target acoustic power production under a given temperature condition. The preliminary test results will be presented

Demonstration of flywheel-based travelling-wave thermoacoustic engine

We report test results on a thermoacoustic engine having a piston-crank-flywheel assembly. The engine maintained steady rotation states when the heating temperature was increased more than 114°C. The rotation frequency increased with the higher heating temperature and reached 14.5 Hz when it was 296°C. The pressure versus volume diagram was created to deduce the power delivered to the piston-crank-flywheel assembly from measurements of the pressure of the working gas and the rotation angle of the flywheel

Comparison of Phase Separation Structures between Undercooled Cu–Fe and Cu–Co Alloys Solidified Under a Static Magnetic Field

An electromagnetic levitation technique superimposed with a static magnetic field was used to investigate the effects of the convection and cooling rate of levitated molten Cu80Fe20 alloy on the size and morphology of induced phase separation structures formed during undercooling. The obtained results were compared to our previous works on the Cu80Co20 alloy, in terms of the size and morphology of the phase-separated structures of dispersed Fe-rich phases. It was revealed that the Sauter mean diameter in the two systems followed the same trend, although the Co-rich phases were larger in size than the Fe-rich ones at higher static magnetic fields. Under a larger static magnetic field, the separated Co-rich phases in Cu–Co alloys had an elongated shape along the direction of the static magnetic field, while the Fe-rich phases in Cu–Fe remained almost spherical in shape. This difference in shapes was attributed to physical properties, particularly their magnetic susceptibility