Launch 09, Heidelberg November The GSI anomaly: experimental status Fritz Bosch, GSI Helmholtzzentrum Darmstadt

FRS - ESR Collaboration 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, U. Spillmann, M. Steck, Th. Stöhlker, B. Sun, T. Suzuki, S. Torilov, H. Weick, M. Winkler, N. Winckler, D. Winters, T. Yamaguchi

1. Detection technique of electron-capture (EC) decay of stored and cooled hydrogen (H)-like ions 2. Results of EC decay of H-like 140 Pr and 142 Pm ions 3. Status of data evaluation of EC decays of H-like 122 I ions 4. Conclusions and next steps Outline

Fragment Separator FRS 1 Detection technique of EC decay of H-like ions Production target Storage Ring ESR Heavy-Ion Synchrotron SIS Linear Accelerator UNILAC

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

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

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

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

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

Schottky frequency spectra Schottky frequency spectra Δαkl

ESR: circumference ≈ 10 4 cm At mean distances of about 10 cm and larger intra-beam-scattering disappeared For 1000 stored ions, the mean distance amounts to about 10 cm "Phase transition" to a linear ion-chain M. Steck et al., PRL 77, 3803 (1996)

Two-body beta decay: monochromatic ν, same q

2 Results of EC-decay of H-like 140 Pr and 142 Pm ions

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

Two-body beta decay

Restriction onto stored H-like parent ions 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

The observables in the GSI experiments 1. Mass M P and charge of parent ion 3. Time t a of daughter appearance 4. Not observed: 140 Pr: T R = 44 eV Delay: 900 (300) msec 142 Pm: T R = 90 eV Delay: 1400 (400) msec from observed frequencies: → p transformed to n (hadronic vertex) → bound e - annihilated (leptonic vertex) → ν created at t d as ν e if LNC holds true 2. Mass M D of cooled daughter ion

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

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

142 Pm: 2740 EC decays from 7011 injections

142 Pm: zoom on the first 33 s after injection

Synopsis ( 140 Pr & 142 Pm) M parent ω (1/s) lab Period lab (s) Amplitude φ (rad) (10) 7.06(8) 0.18(3) 0.4(4) (27) 7.10(22) 0.23(4) - 1.6(4)

µ = µ N (calc.) Coherent excitation of the 1s hyperfine states F = 1/2, F= 3/2 Beat period T = h/ΔE; for ΔE ≈ 1 eV → T ≈ 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?

Asymptotic energy and momentum conservation ΔE ν ≈ Δm 2 /2M P ≈ 3.1· eV Δp ν ≈ - Δm 2 /2 ≈ 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 "Asymptotic" conservation of E, p m 1 2 – m 2 2 = Δm 2 = 8 · eV 2 E 1 – E 2 = ΔE ν p 1 – p 2 = Δp ν if frequency ω in cos(ωt + φ) connected with ΔΕ ν / ћ = Δm 2 /2M p → period T of modulation should be proportional to M p

Decay scheme of 118 Sb 8 - isomer populated with 75% probability !

3 Status of data evaluation of EC decays of H-like 122 I ions Experiment:

Few (1..3) stored parents: inj., 1150 EC decays

Few (1...3) stored parent ions: ~ 1150 EC decays

Few stored parent ions, FFT: f = Hz, 1/f = 6 s

Many parent ions ( ): 5718 injections ~ 4450 EC-decays

Problems of data analysis for many parent ions 1. No correlations, only onset of daughter trace measured 2. Erraneous assignments possible (delayed cooling) → several independent evaluations needed

Background does not show any periodic modulations

Agreement within 0.64s for first decay ≥ 90% for second and third decay ~ 65% low signal-to-noise ratio (signal ~ q 2 ; q = 52) large variance of the amplitudes → restriction onto files with one EC decay only at the expense of significantly reduced statistics

files with many parents and 1 EC decay ~ 1850 decays

files with many parents and 1 EC decay: ω = 1.04(1) s -1

Synopsis M parent ω lab (1/s) Period lab (s) Amplitude φ(rad) [ (1) 6.05(7) 0.21(3) - 0.2(2)] (1) 7.06(8) 0.18(3) 0.4(4) (27) 7.10(22) 0.23(4) - 1.6(4)

Status of the analysis of EC decay of H-like 122 I 1. The data with few parent ions provide about 1150 EC decays which show a modulation with a period of T = 6 s and an amplitude A = The data with many parent ions presently show a reasonable agreement of independent analyses only for the subset of injections where exactly 1 EC decay occurs. This data provide 1850 EC decays which show a modulation with a period of T = 6 s and an amplitude A = 0.2.

Next steps New resonant Schottky pick-up under construction operating at 240 MHz, Q = 2800 To probe whether the modulations could be connected with the spin and/or the hyperfine structure of the H- like ions, the EC decay of He-like 142 Pm will be investigated soon. To probe whether the modulations are connected with the magnetic rigidity, experiments with the same ion type but at different velocity should be performed.