Observation of non-exponential orbital electron capture decays of hydrogen-like 140Pr and 142Pm ions

• DOI: 10.1016/j.physletb.2008.04.062
• Publication Date: 2008-05-09T05:36:58Z
• Authors: Yu.A. Litvinov; F. Bosch; N. Winckler; D. Boutin; H.G. Essel; T. Faestermann; H. Geissel; S. Hess; P. Kienle; R. Knöbel; C. Kozhuharov; J. Kurcewicz; L. Maier; K. Beckert; P. Beller; C. Brandau; L. Chen; C. Dimopoulou; B. Fabian; A. Fragner; E. Haettner; M. Hausmann; S.A. Litvinov; M. Mazzocco; F. Montes; A. Musumarra; C. Nociforo; F. Nolden; W. Plaß; A. Prochazka; R. Reda; R. Reuschl; C. Scheidenberger; M. Steck; T. Stöhlker; S. Torilov; M. Trassinelli; B. Sun; H. Weick; M. Winkler
• Keywords: Nuclear and High Energy Physics; Nuclear Theory; FOS: Physical sciences; 01 natural sciences; 7. Clean energy; Nuclear Theory (nucl-th); High Energy Physics - Phenomenology; High Energy Physics - Phenomenology (hep-ph); 0103 physical sciences; [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]; Nuclear Experiment (nucl-ex); Nuclear Experiment; [PHYS.COND] Physics [physics]/Condensed Matter [cond-mat]

We report on time-modulated two-body weak decays observed in the orbital electron capture of hydrogen-like $^{140}$Pr$^{59+}$ and $^{142}$Pm$^{60+}$ ions coasting in an ion storage ring. Using non-destructive single ion, time-resolved Schottky mass spectrometry we found that the expected exponential decay is modulated in time with a modulation period of about 7 seconds for both systems. Tentatively this observation is attributed to the coherent superposition of finite mass eigenstates of the electron neutrinos from the weak decay into a two-body final state.<br/>12 pages, 5 figures<br/>