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Observation of non-exponential orbital electron-capture decay

Observation of non-exponential orbital electron-capture decay Erice, September 16 - 24, 2009 Fritz Bosch, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. FRS - ESR Collaboration.

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Observation of non-exponential orbital electron-capture decay

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  1. Observation of non-exponential orbital electron-capture decay Erice, September 16 - 24, 2009 Fritz Bosch, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt

  2. FRS - ESR Collaboration D. Atanasov, F. Bosch, D. Boutin, C. Brandau, L.Chen, Ch. Dimopoulou, H. Essel, Th. Faestermann, H. Geissel, E. Haettner, M. Hausmann, S. Hess, P. Kienle, Ch. Kozhuharov, R. Knöbel, 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, W.R. Plass, A. Prochazka, R. Reuschl, Ch. Scheidenberger, D. Shubina, U. Spillmann, M. Steck, Th. Stöhlker, B. Sun, T.Suzuki, S. Torilov, H. Weick, M. Winkler, N. Winckler, D. Winters, T. Yamaguchi

  3. Outline 1. Measurement of orbital electron-capture decay (EC) of stored and cooled H-like ions 2. Observation of non-exponential EC decays of stored H-like 140Pr and 142Pm ionsQuestions, hypotheses and objections3. Preliminary data of EC decay of H-like 122I ionsNext steps

  4. 1 Measurement of EC of stored H-like ions Storage Ring ESR Linear Accelerator UNILAC Fragment Separator FRS Heavy-Ion Synchrotron SIS Production target

  5. Production and Separation of Exotic Nuclei Highly-Charged Ions In-Flight separation Cocktail or mono-isotopic beams Hans Geißel

  6. The ESR : Emax = 420 MeV/u, 10 Tm, e-, stochastic, laser cooling B. Franzke, P. Kienle, Markus Steck, P. Beller†, F. Nolden, Ch. Dimopoulou

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

  8. Schottky Mass-and Lifetime Spectrometry (SMS) Continuous digitizing and storage of raw data

  9. time SMS 4 particles with different m/q Yuri A. Litvinov GSI

  10. Sin(w1) Sin(w2) w4 w3 w2 w1 Sin(w3) time Sin(w4) SMS Fast Fourier Transform

  11. Schottky frequency spectra Δαkl

  12. Two-body orbital electron-capture decay of stored and cooled highly-charged ions

  13. ESR: circumference ≈ 104 cm For 1000 stored ions, the mean distance amounts to about 10 cm At mean distances below about 10 cm intra-beam scatteringdisappears "Phase transition" to a linear ion-chain M. Steck et al., PRL 77, 3803 (1996)

  14. Stochastic (3.5 s) + continuous electron cooling D. Boutin

  15. Two-body beta decay

  16. EC in Hydrogen-like Ions lb+/lEC (neutral atom) ≈1 Expectations: lEC(H-like)/lEC(He-like) ≈ 0.5 FRS-ESR Experiment l(neutral)= 0.00341(1) s-1 G.Audi et al., NPA729 (2003) 3 lb+(bare) = 0.00158(8) s-1 (decay of 140Pr59+) lEC(H-like) = 0.00219(6) s-1 (decay of 140Pr58+) lEC(He-like) = 0.00147(7) s-1 (decay of 140Pr57+) lEC(H-like)/lEC(He-like) = 1.49(8) Y.A. Litvinov et al., PRL 99, 262501 (2007)

  17. Measurement of EC of single stored H-like ions Recording the correlated changes of peak intensities of mother- and daughter ions defines the decay Sensitivity to single stored ions F. Bosch et al., Int. J. Mass Spectr. 251 (2006) 212

  18. Why we have to restrict onto 3 injected ions at maximum ? The variance of the amplitude gets larger than the step 3→4 ions Daughter Amplitude Amplitude Mother Evaluation of amplitude distributions corresponding to 1,2,3-particles Nicolas Winckler

  19. 2 Observation of non-exponential EC of 140Pr and 142Pm

  20. 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 and decay time No third particle involved

  21. 140Pr all runs: 2650 EC decays from 7102 injections Yu.A. Litvinov et al., Phys. Lett. B 664 (2008) 162-168

  22. 142Pm: 2740 EC decays from 7011 injections

  23. 142Pm: zoom on the first 33 s after injection

  24. EC decay of implanted 142Pm &180Re P.A. Vetter et al., Phys. Lett. B 670 (2008) 196 Th. Faestermann et al., Phys. Lett. B 672 (2009) 227 final state is not a true two-body state: neutrino, recoil and phonon of the lattice

  25. β+ decay of 1 or 2 stored H-like 142Pm ions preliminary

  26. EC decay of 1 or 2 stored H-like 142Pm ions

  27. FFT of EC- sc. β+- decay of 1 or 2 stored 142Pm β+ EC

  28. Synopsis (140Pr & 142Pm) • Mparent ω(1/s) Periodlab (s) Amplitude φ(rad) • 140 0.890(10) 7.06(8) 0.18(3) 0.4(4) • 142 0.885(27) 7.10(22) 0.23(4) - 1.6(4)

  29. 2 Questions, hypotheses and objections

  30. Straightforward Questions • 1. Are the periodic modulations real ? • → artefacts are improbable, but • statistical significance only 3.5 σat present 2. If the data are not artefacts, we have to have macroscopic coherence times 3. How can coherence be preserved for a confined motion, stochastic interactions and at continuous observation?

  31. "Quantum Beats" from the Hyperfine States Coherent excitation of the 1s hyperfine states F = 1/2, F= 3/2Beat period T = h/ΔE; for ΔE ≈ 1 eV →T ≈ 10-15 s µ = +2.7812 µN (calc.) Decay can occur only from the F=1/2 (ground) state Periodic spin flip to "sterile" F=3/2 ?→λEC reduced

  32. Periodic transfer from F = 1/2 to "sterile" F = 3/2 ? • 1. Decay constants for H-like 140Pr and 142Pm should get smaller than expected. → NO • 2. Statistical population in these states after • t ≈ max [1/λflip, 1/λdec.] • 3. Phase matching over many days of beam time?

  33. The observables in the GSI experiments 1. Mass MP and charge of parent ion 2. Mass MD of cooled daughter ion 3. Time ta of daughter appearance 4. Not observed: 140Pr: TR = 44 eV Delay: 900 (300) msec 142Pm: TR = 90 eV Delay: 1400 (400) msec from observed frequencies: →p transformed to n (hadronic vertex) → bound e- annihilated (leptonic vertex) → ν created at td as flavour eigenstate νe supposing lepton number conservation

  34. "An essential feature of the GSI experiments is that the neutrino is not detected. Experiments which do not observe the neutrino cannot display interference" A. G. Cohen et al., hep-ph / 0810.4602 and PLB Specific ν flavours are "detected" in all experiments by specific reaction products and by the constraints of energy-, momentum- and lepton number-conservation: W+ + W-→ μ+ + νμ + e-+ νe(bar) creation of neutrino flavour eigenstates states observed by missing momenta supposinglepton number conservation

  35. Charged-Current event at SNO Absorption of a ve Appearance of two protons and of a fast electron: νe- component picked-up from incoming neutrino, supposing lepton number conservation νe + n → p + e- → The GSI experiments observe the creation of an electron-neutrino flavour eigenstate νe at the origin on the same footing as any neutrino detector, via a precise time-resolved measurement of masses and charges

  36. Energy and momentum conservation for a true two-body decay M + p12/2M + E1 = E M + p22/2M + E2 = E "Asymptotic" conservation of E, p E, p = 0 (c.m.) νe (mi, pi, Ei) M, pi2/2M ΔEν ≈ Δm2/2MP ≈ 3.1·10-16 eV Δpν ≈ - Δm2/2< Eν >≈ - 10 -11 eV m12 – m22 = Δm2 = 8 · 10-5 eV2 E1 – E2 = ΔEν p1 – p2 = Δpν if the frequency ω in cos(ωt + φ) = ΔΕν/ ћ = Δm2/2Mp → period T of modulation proportional to the mass of the parent ion

  37. 3 Preliminary data of EC decay of stored H-like 122I ions Experiment: 31.07.2008-18.08.2008

  38. Few (1..3) stored parents: 10 808 inj., 1164 EC decays

  39. Many parent ions (15...30): 5718 injections ~ 4536 EC-decays

  40. Few(1..3) parent ions:10 808 injections, 1164 EC decays preliminary

  41. Fewparent ions: Frequency spectrum (binning = 0.64 s) ● f = 0.17 Hz preliminary preliminary ● ●

  42. Problems of data analysis for many parent ions 1. No correlations, only onset of daughter trace measured 2. Erraneous assignments possible (delayed cooling) 3. Amplitudes show large variance → automatized and several independentmanuel evaluations needed computer analysis very difficult

  43. Next steps • To probe whether the modulations could be connected with the spin and/or the hyperfine structure of the H-like ions, we will investigate next the EC decay of He-like 142Pm. • To probe whether the scaling of the period with the nuclear mass could be connected with the magnetic rigidity, we will • perform experiments with the same ion type but at different velocities. • --------------------------------------------------------------- • Most important: significant improvement ofSchottky detector! • Independent verification or disprove at other facilities is needed • (CSRe ring at IMP/Lanzhou; WITCH setup at ISOLDE/CERN )

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