Measurement of the Isolated Nuclear Two-Photon Decay in $^{72}\mathrm{Ge}$

• DOI: 10.48550/arxiv.2312.11313
• Publication Date: 2023-01-01
• Authors: D. Freire-Fernández; W. Korten; R. J. Chen; S. Litvinov; Yu. A. Litvinov; M. S. Sanjari; H. Weick; F. C. Akinci; M. Albers; M. Armstrong; A. Banerjee; K. Blaum; C. Brandau; B. A. Brown; C. G. Bruno; J. Carroll; X. C. Chen; Ch. J. Chiara; M. L. Cortés; S. Dellmann; I. Dillmann; D. Dmytriiev; O. Forstner; H. Geißel; J. Glorius; A. Görgen; M. Górska; C. J. Griffin; A. Gumberidze; S. Harayama; R. Heß; N. Hubbard; Kayo Ide; Ph. R. John; R. Joseph; B. Jurado; D. Kalaydjieva; K. Kanika; F. G. Kondev; P. Koseoglou; G. Košir; C. Kozhuharov; Iu. N. Kulikov; G. Leckenby; Birgit Lorenz; J. Marsh; A. K. Mistry; A. Ozawa; N. Pietralla; Zs. Podolyák; M. Polettini; M. Sguazzin; R. S. Sidhu; M. Steck; Th. Stöhlker; J. A. Swartz; J. Vesic; P. M. Walker; Takayuki Yamaguchi; R. Zidarova
• Keywords: Radioactive decay; Nuclear isomer

The nuclear two-photon or double-gamma ($2γ$) decay is a second-order electromagnetic process whereby nucleus in an excited state emits two gamma rays simultaneously. To be able to directly measure the $2γ$ rate low-energy regime below electron-positron pair-creation threshold, we combined isochronous mode of storage ring with Schottky resonant cavities. newly developed technique can applied isomers excitation energies down $\sim100$\,keV and half-lives as short $\sim10$\,ms. half-life for first-excited $0^+$ bare $^{72}\mathrm{Ge}$ ions was determined $23.9\left(6\right)$\,ms, which strongly deviates from expectations.