1. Experimental setup 2. Many-ion decay spectroscopy 3. Single-ion decay spectroscopy 4. Discussion 5. Summary and outlook Recent results on the two-body beta-decay studies at GSI TCP 2010 Nicolas Winckler, MPI-K Heidelberg, GSI Darmstadt

Fragment Separator FRS Production target Storage Ring ESR Heavy-Ion Synchrotron SIS Linear Accelerator UNILAC

Production & Separation of Exotic Nuclei 108 m, mbar, 2 MHz, E= 400 MeV/u, stochastic + electron cooling ESR:

"Cooling": enhancing the phase space density Momentum exchange with a cold, collinear e - beam. The ions get the sharp velocity of the electrons, small size and small angular divergence Electron cooling: G. Budker, 1967 Novosibirsk

time SMS 4 particles with different m/q

Sin(  1 ) Sin(  2 ) Sin(  3 ) Sin(  4 ) 11 22 33 44 time Fast Fourier Transform SMS

Small-band Schottky frequency spectra

Two-body beta decay of stored and cooled highly-charged ions

Decay Schemes

Two-body beta decay f scales as m/q Two-body β decay: q does not change Change of f only due to change of mass 260 Hz

EC Decay Rates EC (H-like)/ EC (He-like) = 1.49(8) Yu.A. Litvinov et al., Phys. Rev. Lett. 99 (2007) Pr EC (H-like)/ EC (He-like) = 1.44(6) 142 Pm N. Winckler et al., Phys. Lett. B 679 (2009) 36-40

I. N. Borzov et al., Phys. Atomic nuclei µ = µ N Gamow-Teller transition     Electron Capture in Hydrogen-like Ions Theory: Z. Patyk et al., Phys. Rev. C 77 (2008) λ(H)/λ(He) = (2I+1)/(2F+1) 140 Pr 142 Pm  3/2 Ratio H/He: { TheoryMeasurement 1.49 (9) 1.44 (6)

Single ion decay spectroscopy

Examples of Measured Time-Frequency Traces Continuous observation Detection of ALL EC decays Delay between decay and "appearance" due to cooling Parent/daughter correlation Well defined creation time Restricted counting statistics

140 Pr 58+ all runs: 2650 EC decays from 7102 injections

142 Pm: 2740 EC decays from 7011 injections

142 Pm 60+ : zoom on the first 33 s after injection

Oscillation period T proportional to nuclear mass M ?

Decay scheme of 122 I Experiment:

Decay Statistics Correlations: injections ~1100 EC-decays Many ions: 5718 injections ~4900 EC-decays

Agreement with other analyses <75% (within 10 frames=0.64 s) Restriction to injection with 1 EC-decay 98% Agreement Statistics reduced from ≈ 5600 to 2704 EC decays

Results of visual analyses Agreement within 10 frames (0.64 s): 98% (Difference of 52 EC-decay)

Results of the visual analyses of 122 I (lab.) ω(1/s) Period T(s) Amplitude Phase (rad) λ(1/s) 1.01(1) 6.22(6) 0.171(27) 1.66(34) (12) χ 2 / 81 (pure exponential) = / 81 = 1.36 χ 2 / 78 (modulation) = 71.8 / 78 = 0.92 pure exponential excluded with 98.2% probability

Synopsis of parameters for 140 Pr, 142 Pm, 122 I (lab.) M parent ω(1/s) Period T(s) Amplitude φ(rad) (1) 6.22(6) 0.171(27) 1.66(34) (10) 7.06(8) 0.180(30) 0.40(40) (27) 7.10(22) 0.23(4) -1.60(40) If the period T scales with M parent →T (M = 122) ≈ 6.13 s

Discussion

Are the periodic modulations real ?

Frequency analysis of the Background Periodic Fluctuation of the Background and/or Traces? No significant peak corresponding to T= 6-7 s

Frequency analysis of one daughter trace No significant peak corresponding to T= 6-7 s Periodic Fluctuation of the Background and/or Traces?

"Classical" quantum beats Chow et al., PR A11(1975) 1380 Coherent excitation of an electron in two quantum states, separated by ΔE at time t 0, e.g. 3 P 0 and 3 P 2 Observation of the decay photon(s) as a function of (t-t 0 ) Exponential decay modulated by cos(ΔE/h 2π (t-t 0 )) if ΔE =h/ T << ΔE obs = h/Δt obs  no information whether E 1 or E 2 "which path"? addition of amplitudes

µ = µ N (calc.) Coherent excitation of the 1s hyperfine states F =1/2 & F=3/2 Beat period T = h/ΔE ≈ s Decay can occur only from the F=1/2 (ground) state Periodic spin flip to "sterile" F=3/2 ? → λ EC reduced Quantum Beats from the Hyperfine States

1. Decay constants for H-like 140 Pr and 142 Pm should get smaller than expected. Periodic transfer from F = 1/2 to "sterile" F = 3/2 ? λ EC (H-like) reducedλ EC (He-like) not reduced 2. Coherence over many days of beam time? 1.49 (8) 1.5 Measured  Theory  with a= Periodic transfer 

The electron neutrino appears as coherent superposition of mass eigenstates The recoils appear as coherent superpositions of states entangled with the electron neutrino mass eigenstates by momentum- and energy conservation Beats due to neutrino being not a mass eigenstate? E 1 – E 2 = ΔE ν ≈ Δm²/2M = 3.1 · eV E, p = 0 (c.m.) M, p i 2 /2M ν e (m i, p i, E i ) M + p 1 2 /2M + E 1 = E M + p 2 2 /2M + E 2 = E m 1 2 – m 2 2 = Δm² = 8 · eV 2 |ν e >= cos θ │ν 1 > + sin θ │ν 2 > (From experiments, PDG)

cos (ΔE/ћ t) with T lab = h γ / ΔE ≈ 7s With M =141 amu, γ = 1.43,  Δm² 12 = 2.20(2)· eV 2 ΔE = hγ / T lab = 8.4 · eV ΔE ν = Δm² /2 M = 3.1 · eV  Δm² 12 = 8· eV² With  13 =0 With  13 non zero  Δm² 12 larger (A. B. Balantekin and D. Yilmaz arXiv: v2)

Quantum beats phenomenon connected to neutrino mixing in literature: (See e.g. H.J. Lipkin, A.N. Ivanov, P. Kienle, H. Kleinert, M. Faber) But many objections: (See e.g : C. Giunti, H. Kienert, A.G. Cohen, A. Merle, V.V. Flambaum) Quantum beats of two initial states with an energy splitting of the order of eV Interaction of the 1-electron system with e.g. the magnetic field of the ESR (e.g. G. Lambiase) Interference with the neutrino magnetic moment (c.f. A. Gal) Interference between EC and  + channel (c.f. V.I Isakov) Other suggestions:

Can data of stored and implanted ions be compared? P.A. Vetter et al (2008): Implantation of 142 Pm in a lattice arXiv: Observation of K x-rays: → pure exponential decay observed T. Faestermann et al (2005): Implantation of 180 Re into a lattice: arXiv: Observation of γ of daughter → pure exponential decay observed

Summary and outlook Three H-like systems have been measured: 140 Pr, 142 Pm, 122 I Modulation period seems to scale with M Interpretation of the data still in discussion Improvement of the statistics demands better detection system  new Schottky pick-up installed. Measurement of He-like system and  + branch Measurement at other facilities

FRS-ESR Mass - and Lifetime Collaboration D. Atanasov, P. Beller †, K. Blaum, F. Bosch, D. Boutin, C. Brandau, L. Chen, I. Cullen, Ch. Dimopoulou, H. Essel, Th. Faestermann, B. Franczak, B. Franzke, H. Geissel, E. Haettner, M. Hausmann, S. Hess, P. Kienle, O. Klepper, H.-J. Kluge, Ch. Kozhuharov, R. Knöbel, R. Krücken, J. Kurcewicz, S.A. Litvinov, Yu.A. Litvinov, L. Maier, M. Mazzocco, F. Montes, A.Musumarra, G. Münzenberg, C. Nociforo, F. Nolden, T.Ohtsubo, A. Ozawa, Z. Patyk, W.R. Plass, A. Prochazka, R. Reuschl, Ch. Scheidenberger, D. Shubina, U. Spillmann, M. Steck, Th. Stöhlker, B. Sun, K. Suzuki, K. Takahashi, S. Torilov, M. Trassinelli, S. Trotsenko, P.M. Walker, H. Weick, S. Williams, M. Winkler, N. Winckler, D. Winters, T. Yamaguchi