Negative muon coulomb capture on nitrogen oxide molecules

負ミュオンの酸化窒素への捕獲

二宮 和彦; 伊藤 孝   ; 髭本 亘  ; 喜多 真琴*; 篠原 厚*; 長友 傑*; 久保 謙哉*; Strasser, P.*; 河村 成肇*; 下村 浩一郎*; 三宅 康博*; 三浦 太一*

Ninomiya, Kazuhiko; Ito, Takashi; Higemoto, Wataru; Kita, Makoto*; Shinohara, Atsushi*; Nagatomo, Takashi*; Kubo, Kenya*; Strasser, P.*; Kawamura, Naritoshi*; Shimomura, Koichiro*; Miyake, Yasuhiro*; Miura, Taichi*

負ミュオンが電子に置き換わった原子をミュオン原子と呼ぶ。ミュオン原子形成は負ミュオンと軌道電子の衝突によって、負ミュオンが軌道電子と置き換わることで進むと考えられているが、その詳細については理解されていない。本研究では酸化窒素という単純な分子について、ミュオン原子の形成過程を詳細に調べた。本報告では酸化窒素に対するミュオン原子形成過程について議論を行う。

A muonic atom is an atomic system that contains one negatively charged muon (muon is one of elementally particles) instead of an electron. When a muon is injected in material, the muon is slowing down by collisions with atomic electrons, and then low energy muon is captured on the coulomb field of a nucleus. As a result, the muon forms an atomic orbit around the nucleus, that is, a muonic atom is formed. It is considered that a muon capture phenomenon proceeds through muon collision and replacement with loosely binding electron, however the intrinsic mechanism of muon capture have not been investigated yet. In this study, we examine the formation processes of muonic atoms for nitrogen oxide samples (NO, NO and NO) by measuring muon characteristic X-rays (muonic X-rays) emitted after formation of muonic atoms.