Two-body weak decay of highly charged ions, a tool to study neutrino properties?

Transcription

1 Two-body weak decay of highly charged ions, a tool to study neutrino properties? The detector: ESR Experimental Storage Ring cooling: electron-, stochastic ion detection: Schottky-noise, particle detector Electron-capture decay H-like <-> He-like Decay-rate oscillations: 140 Pr, 142 Pm, 122 I? Interference of neutrino mass eigenstates? Improved detection Resonator Confirmation of Oscillations Thomas Faestermann, Physik Dept. E12 and Universe Cluster

2 Two-body weak decay of highly charged ions, a tool to study neutrino properties? Some Authors TUM: Paul Kienle, T.F., Ludwig Maier GSI Darmstadt: Fritz Bosch, Hans Geissel, Yuri Litvinov, Nicolas Winckler SMI Vienna: Paul Bühler 29. Jan.2013

3 GSI, Darmstadt Experimental Storage Ring particle detector injection ~400 A MeV Schottky noise pickup gas jet pickup stochastic cooling e - -cooler kicker Bernhard Franzke, design Paul Kienle, decision Circumference: 106 m

4 ESR : E max = 420 MeV/u, 10 Tm, e -, stochastic, laser cooling B. Franzke, P. Kienle, Markus Steck, P. Beller, F. Nolden, Ch. Dimopoulou

5 '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

6 Electron Cooling of Heavy Ions transition to a linear chain, ions cannot pass each ~ 4000 ions

7 Stochastic Cooling Nobelpreis 1984 S. van der Meer

8 Schottky Mass-and Lifetime Spectrometry (SMS) To the SIS From the FRS Quadrupoletriplet Hexapolemagnets Dipole magnet Septummagnet Schottky pick-ups Gas-target Electron cooler Schottky Pick-ups amplification summation Quadrupoledublet f ~ 2 MHz 0 FFT RF-Accelerating cavity Fast kicker magnet Stored ion beam Extraction Continuous digitizing and storage of raw data

9 Schottky- Spectroscopy 4 particles with different m/q time

10 Schottky-Mass-Spectroscopy Sin(w 1 ) Sin(w 2 ) Fast Fourier Transform Sin(w 3 ) w 4 w 3 w 2 w 1 Sin(w 4 )

11 Schottky Spectra

12 Single ion detection Schottky Spectra

13 Electron capture decays of H-like and He-like Ions Naive expectation: He-like with 2 K-electrons decays twice as fast as H - like with 1 K-electron

14 140 Pr decay scheme

15 142 Pm decay scheme

16 140 Pr result l EC (H-like)/ l EC (He-like) = 1.49±0.06

17 142 Pm result ion l(b + )[s -1 ]*g l(ec)[s -1 ]*g bare (7) - H-like (3) (1) He-like (6) (1) neutral atom (5) (5) l EC (H-like)/ l EC (He-like) = 1.44±0.06

18 explanation If always F=1/2 for 140 Pr 58+ => l EC (H-like)/ l EC (He-like) = 3/2 Yu. A. Litvinov et al., PRL 99 (2007) ; N. Winckler et al., Phys. Lett. B679 (2009) 36 [ 142 Pm]

19 Interferences in 2-body b-decays?

20 Could there be interference due to different mass eigenstates? Example: quantum beats Coherent excitation of an electron in two quantum states, separated by ΔE = h/t ev for 3 P 1 and 3 P 2 in He. Exponential decay modulated by cos[δω(t-t0)] t (ns) * Chow et al., PR A11(1975)1380

21 Examples of measured time-frequency traces 1. Continuous observation 3. Detection of all EC decays 2. Parent/daughter correlation 4. Delay between decay and "appearance" due to cooling

22 140 Pr all runs: 2650 EC decays from 7102 injections Ampl=0.18(3) n = 0.142(2)

23 142 Pm: zoom on the first 33 s after injection Ampl=0.23(4) n = 0.141(5)

24 122 I decay scheme

25 122 I Ampl=0.15(3) n = 0.164(2)

26 Are there Oscillations in Standard Electron-Capture Experiments if the ESR oscillations are true, with f CM = Hz for 142 Pm, should / could they be seen in a normal experiment? most experiments measuring T 1/2 >> 10 s would irradiate for t >> 1 s smearing out oscillations what signals decay time? a following decay

27 142 Pm decay Phys. Lett. B 670 (2008) Sn( 23 Na,5n) 142 Pm using the Nd K a x-rays

28 180 Re decay scheme 70% EC 99% 903 kev

29 181 Ta( 3 He,4n) 180 Re target: 50 mg/cm 2 beam: 33 MeV single irradiations < 1s Could the GSI Decay Rate Oscillations be Observed in a Standard Electron Capture Decay Experiment? Thomas Faestermann a, Fritz Bosch b, Ralf Hertenberger c, Ludwig Maier a, Reiner Krücken a and Georg Rugel a Phys. Lett. B672 (2009) kev

30 181 Ta( 3 He,4n) 180 Re

31 181 Ta( 3 He,4n) 180 Re FFT n= s -1 T.F. et al, TU München

32 Standard Electron-Capture Experiments Conclusions no oscillations no contradiction with GSI data, because: final state not sharp: t =11ns => de = 10-7 ev recoil momentum defined by phonon spectrum

33 ordinary neutrino oscillations n 1 n source weak interaction e cos n 1 + sin n 2 n 2 n 1 detector weak interaction cos n e + sin n t 1, 2 2 L L / c L m c + 1, 2 1 b c 2 1-1/ g c 2E 2 4 n 2 sin n e - cos n but with different phases E exp( i t ) 1,2 E t L 2 c m 2 E c 4

34 decay rate oscillations? created at t=0 decay time observed - e weak interaction n 1,2 140 Pr Ce Transition to 2 distinct states: 1) 140 Ce + n 1 with recoil energy E R1 2) 140 Ce + n 2 with recoil energy E R2 E R1, 2 p 2 1, 2 2M E 2 - m 2Mc 2 1, 2 2 c 4 E R m 2 c 2Mc ev MeV ev if the 2 amplitudes interfere between creation and decay then decay probability oscillates with w E R / 0. 5s - 1, T 14s

35 245 MHz resonator

36 The new 245 MHz Schottky Resonator: Q 2000, ε 9.8 New resonatorcavity (2010) Pm Nd Pm Nd Old Schottky pickup (1992) 30 th harmonic same EC decay S / N improved by a factor > 100

37 37

38 longitudinal recoil velocity distribution

39 longitudinal recoil velocity distribution reflects neutrino angular distribution and helicity

40 Capacitive pick-up: 3098 EC decays (at most 2) T = 7.12(11) s, a = 0.134(27)

41 245 MHz resonator: ω = 2π/T = 0.884(14)/s, T = 7.11(11) s, a = 0.107(24)

42 245 MHz resonator: 2907 β + decays, a = 0.027(27) within 6.6 s < T < 7.7 s

43 Paul Kienle et al., Phys. Lett. B 726 (2013) correlated EC- decays 245 MHZ resonator period T = 7.08(9) s amplitude a = 0.147(28) phase φ = 2.55(37) rad. χ 2 /dof = 33.9/51 capacitive pick-up period T = 2π/ω = 7.15(9)s amplitude a = 0.161(28) phase φ = 1.98(35) rad. χ 2 /dof = 65.5/51

44 Synopsis SNO, KAMLAND ampl w Lab 2ħw Lab g Mc 2 m 2 c 4 [s -1 ] [10-4 ev 2 ] [10-4 ev 2 ] 140 Pr 0.18(3) 0.890(11) 2.182(27) PLB664(2008) 142 Pm 0.23(4) 0.885(31) 2.20 ( 8) PLB664(2008) 0.759(20)? 142 Pm 0.134(27) 0.882(14) 2.194(35) PLB726(2013) 142 Pm 0.107(24) 0.884(14) 2.199(35) PLB726(2013) 122 I 0.15(3) 1.022(11) 2.184(24) to be published

45 Theory far from complete A.N. Ivanov, P. Kienle; arxiv: H.J. Lipkin; arxiv: explain everything interference M. Peshkin no interference due to n A. Merle no interference due to n C. Giunti no interference due to n V.V. Flambaum, PRL104 (2010) no interference due to n A. Gal, NPA 842 (2010) 102 no interference due to n (n) G. Lambiase, G. Papini, G. Scarpetta no interference due to n PLB 718 (2013) 998 hyperfine interaction Indeed, 2 (3) distinct configurations in the final state, D(P=P 1 )+n 1 or D(P=P 2 )+n 2 But, can they be distinguished in principle?

46 Summary EC decay: 1 electron may be better than 2 electrons Oscillations in 2-body decay rate: period scales with mass of nucleus for 3 systems not observed with neutral atom not observed for 3-body b-decay => weak interaction origin reproducible with different detector but amplitude differs most theoreticians exclude neutrino origin rapid reaction task force meeting July 2014

47 Summary EC decay: 1 electron may be better than 2 electrons Oscillations in 2-body decay rate: period scales with mass of nucleus for 3 systems not observed with neutral atom not observed for 3-body b-decay => weak interaction origin reproducible with different detector but amplitude differs most theoreticians exclude neutrino origin rapid reaction task force meeting July 2014