New Parameterization in Muon Decay and the Type of Emitted Neutrino

Normal muon decay, $\mu^{+} \to e^{+}\nu_{e}\bar{\nu_{\mu}}$, is studied as a tool to discriminate between the Dirac and Majorana types of neutrinos and to survey the structure of the weak interaction. It is assumed that massive neutrinos mix with one another and that the interaction Hamiltonian consists of the $V-A$ and $V+A$ charged currents. A new set of parameters used in place of the Michel parameters is proposed for the positron distribution. Explicit forms of these new parameters are obtained by assuming that the masses are less than 10 eV for light neutrinos and sufficiently large for heavy Majorana neutrinos, which are not emitted in the muon decay. It is shown that a possible method to discriminate between the Dirac and Majorana cases is to use a characterization given by the $\chi^2$ fitting of their spectra. It is also confirmed that the theoretical predictions in the Majorana neutrino case are almost the same as those obtained from the standard model. Indeed, their differences cannot be distinguished within the present experimental precision.Comment: 30 page

A Shock-Induced Pair of Superbubbles in the High-Redshift Powerful Radio Galaxy MRC 0406-244

We present new optical spectroscopy of the high-redshift powerful radio galaxy MRC 0406$-$244 at redshift of 2.429. We find that the two extensions toward NW and SE probed in the rest-frame ultraviolet image are heated mainly by the nonthermal continuum of the active galactic nucleus. However, each extension shows a shell-like morphology, suggesting that they are a pair of superbubbles induced by the superwind activity rather than by the interaction between the radio jet and the ambient gas clouds. If this is the case, the intense starburst responsible for the formation of superbubbles could occur $\sim 1 \times 10^9$ yr ago. On the other hand, the age of the radio jets may be of the order of $\sim 10^6$ yr, being much shorter than the starburst age. Therefore, the two events, i.e., the starburst and the radio-jet activities, are independent phenomena. However, their directions of the expanding motions could be governed by the rotational motion of the gaseous component in the host galaxy. This idea appears to explain the alignment effect of MRC 0406$-$244.Comment: 4 pages (emulateapj.sty), Fig. 1 (jpeg) + Fig.2 (eps). Accepted for publications in ApJ (Letters

Webを用いた自主学習型天文分光解析体験プログラムの開発

application/pdf一般市民も高い関心を寄せ学術分野でも多数の成果が報告されている天文分野ではあるが,高校卒業時までに系統的に学習できる機会は少ない．このような状況を改善すべく，天文学に興味・関心を持った高校生・大学生が自主的・体験的に現代天文学の基礎的学習ができる教材の開発を行った．既に天体画像を主とした学習教材を作成しているため，本研究では分光データに焦点をあて、10種のテーマを取り上げた．分光データからは天体の温度や運動、発光機構についての情報を得ることができる．一連のテーマについて実習することで，天文学の基本的な考え方、観測原理を系統的に学習できる教材となっている．Astronomy is one of the most popular science field and publicized new discoveries receive strong interest from a large number of people. However, there are not enough opportunities to learn astronomy until high school graduation in Japan. We have developed self-directed learning materials which can be used to learn basics of modern astronomy systematically through practices to give students who are interested in astronomy more chances to learn. In this study, 10 themes handling spectral data were selected because we already developed materials for analyzing imaging data. Spectral data give us information about temperature, movements and emission mechanism of astronomical objects. It is possible for students to acquire the basic concepts and analytical approaches about modern astronomy by exercising the series of our materials.2014年度～2016年度科学研究費補助金(基盤研究(C))研究成果報告書2635019

天文分野を対象とした自主学習型解析体験教材の開発Ⅰ

application/pdf天文学に興味・関心はあるものの高校地学の開講率低迷により高校での系統的な学習機会が得られない高校生 を念頭に、自主学習型の天文解析体験プログラムの開発を行った。このプログラムは15のテーマから構成されて おり、太陽系から宇宙膨張まで様々な階層の天体を取り上げている。またテーマ毎に現代天文学の基本的な考え 方が組み込まれており、テーマを一通り実習することにより天文学の系統的な学習ができるように配慮している。 本プログラムの有効性検証のため、スーパーサイエンスハイスクールでの授業の一環として高校生に体験学習を してもらったところ、実習内容を面白いと感じた割合は9割を超え、天体物理学的な考え方が伝えられたものと 考える。また前提となる天文学の知識がなくても、実習テーマの概容は十分に習得できることが確認できた

時間変動現象に主眼を置いた自主学習型天文解析体験プログラムの開発

application/pdf天文分野は理科の中でも興味・関心が高い分野であるが、一方で高校での地学開講率は低く、天文学に関心を持つ高校生が系統的な学習をする機会は必ずしも多くない。本研究では、これまで我々が開発してきた教材ではカバーしていなかった宇宙における時間変動現象に焦点を当てた教材の開発を行った。天体の時間変動は主として天体の位置変化と明るさ・色の変化の２種に大別でき、各々から天体の運動情報、サイズや表面温度の情報等を推定することができる。そこでテーマをこの2つのカテゴリーに分け、テーマ毎に時間変動現象に関する基本的な考え方・解析手法を取得できるようにした。開発した教材は順次公開していく予定である。The high school students have few opportunities for studying astronomy in a high school because the number of lectures taken in a high school is small though astronomy is much popular field in science. In this study, teaching materials focused on time-variation phenomena in astronomy which were not covered in our project for developing astronomical teaching materials. Time variation phenomena is roughly divided into two categories,change of positions of astronomical objects and luminosity and/or color variations of objects. We selected 10 subjects, 7 themes are related with change of positions and three are luminosity variations. Each subject were composed of an introduction of a phenomenon, explannation of date-reduction procedure, analysis data, tips for interpreting analyzed data. Developed materials will be opened sequentially.2017年度～2019年度科学研究費補助金(基盤研究(C))研究成果報告書17K0097