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

Productiontarget

StorageRingESR

Heavy-IonSynchrotron

SIS

LinearAccelerator

UNILAC

Production & Separation of Exotic Nuclei

108 m, 10-11 mbar, 2 MHz, E= 400 MeV/u,

stochastic + electron cooling

ESR:

"Cooling": enhancing the phase space density

Momentum exchangewith a cold, collinear e- beam. The ionsget the sharp velocity of the electrons,small size and small angular divergence

Electron cooling: G. Budker, 1967 Novosibirsk

time

SMSSMS

4 particles with different m/q

Sin(1)

Sin(2)

Sin(3)

Sin(4)

1234time

Fast Fourier Transform

SMSSMS

0 1 0 . 0 2 0 . 0 3 0 . 0 4 0 . 0 5 0 . 0 6 0 . 0 7 0 . 0 8 0 . 00

5

1 0

8 0 . 0 9 0 . 0 1 0 0 . 0 1 1 0 . 0 1 2 0 . 0 1 3 0 . 0 1 4 0 . 0 1 5 0 . 0 1 6 0 . 0

1 6 0 . 0 1 7 0 . 0 1 8 0 . 0 1 9 0 . 0 2 0 0 . 0 2 1 0 . 0 2 2 0 . 0 2 3 0 . 0 2 4 0 . 0

240.0 250.0 260.0 270.0 280.0 290.0 300.0 310.0 320.0

know n m asses A q+X unknow n m asses

N um ber of channels 216

R ecord ing tim e 30 sec

188 78+Pt

0

5

10

0

5

10

0

5

10

Frequency / kHz

Inte

nsity

/ ar

b. u

nits

201 84+

194 81+Tl

182 76+Pt182 76+

182 76+

189 79+

Ir

O s

Po

Hg

189 79+Au

177 74+W

196 82+Bi

196 82+Pb

184 77+Pt

184 77+Ir198 83+Bi

191 80+Tl

191 80+Hg

194 81+Au

200 83+Bi

183 76+Ir

183 76+O s

195 81+Tl195 81+PbPb

188 78+ 178 74+Re

190 79+Au

197 82+Bi

197 82+Pb

185 77+Ir

185 77+Pt192 80+Tl

192 80+Hg

199 83+Bi187 78+Pt

187 78+Au

Pb

190 79+Hg

IrAu 181 75+

198 82+Pb

193 80+Tl

193 80+Hg

194 80+Tl194 80+

189 78+

Tl191 79+Hg

187 77+

199 82+ Pb

Hg

196 81+

204 84+

Pt

Pb

Pt Ir186 77+

Po

187 77+Au

BiPbPb

182 75+Ir

194 80+Hg 189 78+Au189 78+

201 83+Po

201 83+Bi184 76+

184 76+O s

191 79+Au

203 84+Po

186 77+Pt

186 77+Ir181 75+R e198 82+Bi

193 80+Pb199 82+

O s181 75+

200 82+Bi

195 80+Tl

197 81+Pb

197 81+Bi 192 79+Hg

192 79+Au

198 81+Bi

198 81+Pb193 79+Tl

193 79+Hg

188 77+Au 205 84+Po

200 82+Pb200 82+Po195 80+Pb

190 78+Hg

190 78+Au

185 76+Pt

202 83+Po

202 83+Bi 197 81+Tl198 81+Pb

188 77+Pt

A q+X

15

0m

,g

6

5+

Dy

150

65

+

Tb

143

6

2+

143

m,g

6

2+

Eu S

m

157

68+

Er

127

55+

Cs

157

6

8+T

m

173

7

5+

166

72

+1

66

72+

180

78

+P

t

Re

Hf

Ta

152

6

6+

152

6

6+

Ho

Dy

159

6

9+

159

6

9+

13

6

59+

Tm

Yb

Pr

W

164

71+

171

74

Lu

16

4

71+

Hf

14

5

6

3+

122

53+

Gd

I

175

7

6+

161

70

+

138

6

0+161

70

+

16

8

7

3+16

8

73+

Os

TaW

Yb

Nd

Lu

14

9

65+

Tb

156

68

+

156

6

8+

Er

Tm

154

67+

154

67+

HoEr

163

71+

147

64

+

14

7

6

4+

147

6

4+

Dy

Tb

Gd

Lu

165

72

+1

65

7

2+

17

2

7

5+

163

7

1+

170

74

+

Hf

TaRe

W

Hf

10000 20000 30000 40000 50000 60000 70000 80000 90000 100000

8

7

6

5

4

3

2

1

0

Frequency / H z

Inte

nsity

/ ar

b. u

nits

m ass know n m ass unknow n

Small-band Schottky frequency spectra

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

charged ionscharged 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) 262501

140Pr

EC(H-like)/EC(He-like) = 1.44(6)

142Pm

N. Winckler et al., Phys. Lett. B 679 (2009) 36-40

I. N. Borzov et al., Phys. Atomic nuclei

µ = +2.7812µN

Gamow-Teller transition

Electron Capture in Hydrogen-like IonsElectron Capture in Hydrogen-like Ions

Theory:

Z. Patyk et al., Phys. Rev. C 77 (2008) 014306

λ(H)/λ(He) = (2I+1)/(2F+1)

140Pr 142Pm

3/2 3/2

Ratio H/He: {Theory Measurement

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 timeRestricted counting statistics

140Pr58+ all runs: 2650 EC decays from 7102 injections

142Pm: 2740 EC decays from 7011 injections

142Pm60+: zoom on the first 33 s after injection

Oscillation period T proportional to nuclear mass M ?

Decay scheme of 122I

Experiment: 31.07.2008-18.08.2008

Decay Statistics

Correlations: 10.808 injections ~1100 EC-decaysMany 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 122I (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) 0.0043(12)

χ2 / 81 (pure exponential) = 109.9 / 81 = 1.36

χ2 / 78 (modulation) = 71.8 / 78 = 0.92

pure exponential excluded with 98.2% probability

Synopsis of parameters for 140Pr, 142Pm, 122I (lab.)

Mparent ω(1/s) Period T(s) Amplitude φ(rad)

122 1.01(1) 6.22(6) 0.171(27) 1.66(34)

140 0.890(10) 7.06(8) 0.180(30) 0.40(40)

142 0.885(27) 7.10(22) 0.23(4) -1.60(40)

If the period T scales with Mparent

→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 t0, e.g. 3P0 and 3P2

Observation of the decay photon(s) as a function of (t-t0)

Exponential decay modulated bycos(ΔE/h 2π (t-t0))

if ΔE =h/T << ΔEobs = h/Δtobs

no information whether E1 or E2

"which path"? addition of amplitudes

µ = +2.7812 µN (calc.)

Coherent excitation of the 1s hyperfine states F =1/2 & F=3/2 Beat period T = h/ΔE ≈ 10-15 s

Decay can occur only from the F=1/2 (ground) state

Periodic spin flip to "sterile" F=3/2 ? → λEC reduced

Quantum Beats from the Hyperfine States

1. Decay constants for H-like 140Pr and 142Pm should get smaller than expected.

Periodic transfer from F = 1/2 to "sterile" F = 3/2 ?

λEC (H-like) reduced λEC (He-like) not reduced

2. Coherence over many days of beam time?

1.49 (8)1.5

Measured Theory

with a=0.2

1.23Periodic 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?

E1 – E2 = ΔEν ≈ Δm²/2M = 3.1 · 10-16 eV

E, p = 0 (c.m.)

M, pi2/2M

νe (mi, pi, Ei)

M + p12/2M + E1 = E

M + p2

2/2M + E2 = E

m12 – m2

2 = Δm² = 8 · 10-5 eV2

|νe>= cos θ │ν1> + sin θ │ν2>

(From experiments, PDG)

cos (ΔE/ћ t) with Tlab = h γ / ΔE ≈ 7s

With M =141 amu, γ = 1.43,

Δm²12 = 2.20(2)· 10-4 eV2

ΔE = hγ / Tlab = 8.4 · 10 -16 eV

ΔEν = Δm² /2 M = 3.1 · 10 -16 eV

Δm²12 = 8· 10-5 eV²With 13=0

With 13 non zero Δm²12 larger(A. B. Balantekin and D. Yilmaz arXiv:0804.3345v2)

•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 10-16 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 142Pm in a lattice

arXiv: 0807.0649 Observation of K x-rays:

→ pure exponential decay observed

T. Faestermann et al (2005): Implantation of 180Re into a lattice:

arXiv:0807.3651 Observation of γ of daughter

→ pure exponential decay observed

Summary and outlook

•Three H-like systems have been measured: 140Pr, 142Pm, 122I•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