On the Power Spectrum Density of Gamma Ray Bursts

Gamma ray bursts (GRBs) are known to have short-time variability and power-law behavior with the index -1.67 in the power spectrum density. Reanalyzing the expanded data, we have found a) the power-law comes from the global profile of the burst and not from the self-similar shots nor rapid fluctuations in the luminosity profile. b) The power indices vary from burst to burst and the value -1.67 is given simply as the mean value of the distribution; there is no systematic correlation among GRBs to yield the power law.Comment: 10 pages, 4 figures, submitted to ApJ Letter

Loop corrections to dark matter direct detection in a pseudoscalar mediator dark matter model

If dark matter (DM) is a fermion and its interactions with the standard model particles are mediated by pseudoscalar particles, the tree-level amplitude for the DM-nucleon elastic scattering is suppressed by the momentum transfer in the non-relativistic limit. At the loop level, on the other hand, the spin-independent contribution to the cross section appears without such suppression. Thus, the loop corrections are essential to discuss the sensitivities of the direct detection experiments for the model prediction. The one-loop corrections were investigated in the previous works. However, the two-loop diagrams give the leading order contribution to the DM-gluon effective operator ($\bar{\chi} \chi G^{a}_{\mu \nu} G^{a \mu \nu}$) and have not been correctly evaluated yet. Moreover, some interaction terms which affect the scattering cross section were overlooked. In this paper, we show the cross section obtained by the improved analysis and discuss the region where the cross section becomes large.Comment: 34 pages, 11 figures, 6 tables, the version published in JHE

Expression Activities in Art Education to Think About a Sustainable Society: Application of Contemporary Art to the Development of Subjects

In 2017, the Yokohama Triennale was held in Japan. One of the participants was a contemporary artist, Olafur Eliasson, who uses light in his work. His project involved the fabrication of a lamp together with refugees and members of the public. This he named, the "Green Light" project. The Green Light lamp was designed to help people to learn and collaborate, and through the process of lamp production, gain a better understanding of how we can live together. Through the process of creative expression in contemporary art, we develop a "deepening of ideas within the expression of works" and record the idea development processes with junior high school students. To investigate the possibility of adoption of modern art as a method for ESD (Education for Sustainable Development) and consider this as a subject of analysis within the art department, on October 9th, 2017, I participated in a workshop paired with the student to make a lamp as part of the Green Light project. Through this experience, I researched the student conceptual understanding of the "refugee problem" and investigated whether this activity could indeed relate to a "sustainable society". Societally we should consider global problems from an international perspective. At the same time, we need to consider the sustainability of Japan within a world context. While interacting closely with others, using our hands and eyes to solve various problems that are intertwined we can internalize these interactions. The art department needs a systematic approach to help us express shape colour and ourselves.Art and Design Research for Sustainable Development ; September 22, 2018Conference: Tsukuba Global Science Week 2018Date: September 20-22, 2018Venue: Tsukuba International Congress Center Sponsored: University of Tsukub