Few-electron highly charged muonic Ar atoms verified by electronic $K$ x rays

• DOI: 10.48550/arxiv.2407.07977
• Publication Date: 2024-07-10
• Authors: Taiga Okumura; Toshiyuki Azuma; D. A. Bennett; W. B. Doriese; Malcolm Durkin; Jim Fowler; Johnathon D. Gard; Takuya Hashimoto; R. Hayakawa; Yuto Ichinohe; P. Indelicato; T. Isobe; S. Kanda; Daiji Kato; M. Katsuragawa; Naomi Kawamura; Yasushi Kino; Nao Kominato; Yasuhiro Miyake; Keith M. Morgan; Hirofumi Noda; Galen O`Neil; S Okada; Kenichi Okutsu; N. Paul; C. D. Reintsema; Takashi Sato; D. R. Schmidt; K Shimomura; P. Strasser; Daniel S. Swetz; Toshiya Takahashi; Shigeki Takeda; Satoru Takeshita; M. Tampo; H. Tatsuno; K. Tőkési; X.M Tong; Yuichi Toyama; Joel N. Ullom; Shigeo Watanabe; Seiji Yamada; Takuma Yamashita
• Keywords: Exotic atom

Electronic $K$ x rays emitted by muonic Ar atoms in the gas phase were observed using a superconducting transition-edge-sensor microcalorimeter. The high-precision energy spectra provided clear signature of presence accompanied few electrons, which have never been before. One-, two-, and three-electron bound, i.e., H-like, He-like, Li-like, identified from electronic hyper-satellite rays. These are after charge transfer process collisions with surrounding atoms. With aid theoretical calculations, we confirmed that peak positions consistent x-ray energies highly charged Cl ions, intensities reflecting deexcitation dynamics successfully understood taking into account interaction between muon bound electrons.