Direct observation of muonic molecules in resonance states critical to muon catalyzed fusion
Muon catalyzed fusion (μCF) is a plasma-free process in which the formation of muonic hydrogen molecules precedes and enables fusion between their constituent nuclei. Despite decades of study, the reaction dynamics of μCF remain elusive. Recent theories predict that resonance states of the muonic molecules play a key role and that these states can be probed using x-ray techniques. Using an array of transition-edge sensor microcalorimeters with 10-fold improved energy resolution compared to conventional silicon detectors, we observed x-rays from resonance states of muonic deuterium molecules despite an intense background. The spectrum is well explained by high-precision calculations incorporating the vibrational states. This work identifies the long-overlooked resonance state pathway as crucial in μCF and provides the direct evidence of the efficient muonic molecular formation.
Authors
- Takuma Yamashita (ORCID: https://orcid.org/0000-0003-2225-2260)
- H. Tatsuno (ORCID: https://orcid.org/0000-0001-8682-1579)
- M. S. Durkin
- Izumi Umegaki (ORCID: https://orcid.org/0000-0001-9271-3574)
- Hirofumi Noda (ORCID: https://orcid.org/0000-0001-6020-517X)
- T. Hashimoto (ORCID: https://orcid.org/0000-0001-6973-4895)
- R. Hayakawa (ORCID: https://orcid.org/0000-0002-3752-0048)
- K. Ishida (ORCID: https://orcid.org/0000-0002-3458-8506)
- Tadayuki Takahashi (ORCID: https://orcid.org/0000-0001-6305-3909)
- D. A. Bennett (ORCID: https://orcid.org/0000-0003-3011-3690)
- Daniel S. Swetz (ORCID: https://orcid.org/0000-0002-8192-2175)
- M. Tampo (ORCID: https://orcid.org/0000-0002-5708-6795)
- K. Shimomura (ORCID: https://orcid.org/0000-0002-9501-6149)
- P. Strasser
- T. Azuma
- K. Sasaki
- Y. Kino
- S. Okada (ORCID: https://orcid.org/0000-0002-5349-8549)
- Y. Miyake
- Y. Toyama
- Kenichi Okutsu (ORCID: https://orcid.org/0000-0003-0713-4565)
- Johnathon D. Gard (ORCID: https://orcid.org/0000-0003-4195-9544)
- D. R. Schmidt (ORCID: https://orcid.org/0000-0002-5764-0194)
- Toshiki Sato (ORCID: https://orcid.org/0000-0001-9267-1693)
- S. Yamada (ORCID: https://orcid.org/0000-0003-4808-893X)
- Shin Watanabe (ORCID: https://orcid.org/0000-0003-0441-7404)
- KJ Morgan
- N. Kawamura
- J. W. Fowler
- S. Kanda
- Y. Ichinohe
- W. B. Doriese
- H. Natori
- G. C. O'Neil
- T. Okumura
- R. Konishi
- J. N. Ullom
- C. D. Reintsema
- R. Nakashima
Institutions
- National Institute of Standards and Technology (US)
- Rikkyo University (JP)
- High Energy Accelerator Research Organization (JP)
- Pioneer (United States) (US)
- Meiji University (JP)
- Kavli Institute for the Physics and Mathematics of the Universe (JP)
- Chubu University (JP)
- University of Colorado Boulder (US)
- Tohoku University (JP)
- National Institute for Fusion Science (JP)
- RIKEN (JP)
- Institute of Space and Astronautical Science (JP)
- RIKEN Nishina Center (JP)
- Tokyo Metropolitan University (JP)
- The University of Tokyo (JP)
Publication Details
- Journal
- Science Advances
- Published
- 2026-04-15
- DOI
- https://doi.org/10.1126/sciadv.aed3321
- Primary Topic
- Muon and positron interactions and applications
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Japan Society for the Promotion of Science
- RIKEN