Recent results on the two-body
beta-decay studies at GSI
TCP 2010
Nicolas Winckler, MPI-K Heidelberg, GSI Darmstadt
1. Experimental setup
2. Many-ion decay spectroscopy
3. Single-ion decay spectroscopy
4. Discussion
5. Summary and outlook
Storage
Ring
ESR
Fragment
Separator
FRS
Production
target
Linear
Accelerator
UNILAC
Heavy-Ion
Synchrotron
SIS
Production & Separation of Exotic Nuclei
ESR:
108 m, 10-11 mbar, 2 MHz,
E= 400 MeV/u,
stochastic + electron cooling
"Cooling": enhancing the phase space density
Electron cooling: G. Budker, 1967 Novosibirsk
Momentum exchange
with a cold, collinear e- beam. The ions
get the sharp velocity of the electrons,
small size and small angular divergence
SMS
4 particles with
different m/q
time
SMS
Sin(w1)
Sin(w2)
Fast Fourier Transform
time
Sin(w
3)
w4
Sin(w4)
w3
w2
w1
Small-band Schottky frequency spectra
10
74
197
195
W
200
193
185
Pt
mass unknown
Tl
83+
197
Bi 81+
193
Tl 81+
191
Au
201
189
189
Po 83+
78+
75+
Hg 78+
Pt
Hg 79+
191
Bi 83+
78+
198
184
Ir
186
Au79+
186
184
76+
Os
76+
203
Pt
Ir
Po 84+
186
77+
193
77+
181
198
Bi
82+
181
Au77+
184
177
W
184
Pt 77+
Ir
181
74+
0
10000 0240.020000
30000
250.0
40000
260.0
X
71+
74+
Lu
W
known masses
unknown masses
160.0
81+
Tl
78+
201
163
182
Pb 81+
Tm68+
Dy
Tb 64+
147
Gd64+ 163 71+
Hf
156
220.0
Pt
76+
182
182
Po 84+
76+
Ir
Os76+
230.0
172
147
q+
q+
Pt
194
147
X
187
170
67+
Er
154
67+
Ho
Nd
60+
210.0
138
A
Os75+
Au 78+
Bi 83+
Hg 80+
150.0
64+
70+
161
70+
Lu
161
I
122 53+
Gd63+
200.0
A
198
Tl 80+
Yb
77+
Ir
187
193
Re 75+
194
154
73+
W
Hg 80+
Tl 80+
Pt
77+
185
145
191
Hg 80+
Ir
Pb 80+
75+
140.0
199
192
185
168
152
190.0
192
Bi 82+
Dy
Yb
77+
191
Au 79+
130.0
Pb 82+
152
66+
69+
Re74+
Pr 59+ 159
Eu 62+
Sm62+
143
Bi
82+
178
180.0
Pb 82+
150m,g
196
76+
Dy
65+
Tb
180
65+
55+
196
Cs
Hg
79+
150
189
Au79+
Ir
170.0
127
189
Pt 78+
Er
157
Tm
0
160.0
10
183
Os 76+
136
183
72+
Pt
Ta
Au78+
68+
188
78+
166
188
175
190
5
197
66+
Pb 81+
Ho
Tl
76+
195
197
Hg 79+
81+
Os
190
195
120.0
Tm
Bi 83+
110.0
69+
100.0
Tl 80+
Pb 82+
72+
189
80.0
Hf
Hg 80+
70.0
165
196
60.0
240.0
65+
Tl 80+
50.0
Tb
165
72+
Ta
194
Lu
200
Hg 79+
16
149
194
40.0
80+
90.0
192
76+
Re
30.0
159
80.0
10
5
202
173
0
1
mass knownPo
Hg 78+
Po 84+
201
Ir
190
Au79+
81+
68+
77+
Pb 82+
195
Pb80+
197
Er
75+
Pt
20.0
Re
182
187
68+
2
77+
157
3
Au
71+
4
187
205
Pb 82+
164
5
199
164
5
Bi
Pb
82+
Po 84+
Hf 71+
204
Au77+
200
Po 82+
168
166
194
199
143m,g
6
77+
200
188
Tl 79+
Pt
Bi 83+
156
10.0
0
188
Hg 79+
202
Au78+
75+
193
10
Intensity / arb. units
Intensity / arb. units
0
Bi
Pb 81+
72+
7
81+
192
190
73+
198
198
Pb 81+
Tl 80+
Bi 82+
Ta
5
Hf
171
8
Number of channels 2
Recording time 30 sec
Bi 83+
50000
270.0
280.0
60000
Frequency
/ kHz /
Frequency
Hz
290.0
70000
80000
300.0
310.0
320.0
100000
90000
Two-body beta decay of stored
and cooled highly-charged ions
Decay Schemes
Two-body beta decay
260 Hz
f scales as m/q
Two-body β decay:
q does not change
Change of f only due
to change of mass
EC Decay Rates
140Pr
lEC(H-like)/lEC(He-like) = 1.49(8)
Yu.A. Litvinov et al., Phys. Rev. Lett. 99 (2007) 262501
142Pm
lEC(H-like)/lEC(He-like) = 1.44(6)
N. Winckler et al., Phys. Lett. B 679 (2009) 36-40
Electron Capture in Hydrogen-like Ions
Gamow-Teller transition 1+  0+
µ = +2.7812µN
Theory:
I. N. Borzov et al., Phys. Atomic nuclei
λ(H)/λ(He) = (2I+1)/(2F+1)
Z. Patyk et al., Phys. Rev. C 77 (2008) 014306
Theory
Ratio H/He:
{
 3/2
142Pm
 3/2
140Pr
Measurement
1.49 (9)
1.44 (6)
Single ion decay spectroscopy
Examples of Measured Time-Frequency Traces
Continuous observation
Detection of ALL EC decays
Parent/daughter correlation
Delay between decay and
"appearance" due to cooling
Well defined creation time
Restricted 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-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
ω(1/s)
122I
Period T(s) Amplitude Phase (rad)
1.01(1)
6.22(6)
0.171(27)
1.66(34)
(lab.)
λ(1/s)
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 ?
Periodic Fluctuation
of the Background and/or Traces?
Frequency analysis of the Background
No significant peak
corresponding to T= 6-7 s
Periodic Fluctuation
of the Background and/or Traces?
Frequency analysis of one daughter trace
No significant peak
corresponding to T= 6-7 s
"Classical" quantum beats
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 by
cos(ΔE/h 2π (t-t0))
if ΔE =h/T << ΔEobs = h/Δtobs
no information whether E1 or E2
"which path"? addition of amplitudes
Chow et al., PR A11(1975) 1380
Quantum Beats from the Hyperfine States
Coherent excitation of the 1s hyperfine states F =1/2 & F=3/2
Beat period T = h/ΔE ≈ 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
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.
λEC (H-like) reduced
Measured  1.49 (8)
Theory  1.5
λEC (He-like) not reduced
Periodic transfer  1.23
with a=0.2
2. Coherence over many days of beam time?
Beats due to neutrino being not a mass eigenstate?
The electron neutrino appears as coherent superposition of mass eigenstates
|νe>= cos θ │ν1> + sin θ │ν2>
The recoils appear as coherent superpositions of states entangled with the
electron neutrino mass eigenstates by momentum- and energy conservation
E, p = 0 (c.m.)
νe (mi, pi, Ei)
M + p12/2M + E1 = E
M + p22/2M + E2 = E
M, pi2/2M
(From experiments, PDG)
m12 – m22 = Δm² = 8 · 10-5 eV2
E1 – E2 = ΔEν ≈ Δm²/2M = 3.1 · 10-16 eV
cos (ΔE/ћ t) with Tlab = h γ / ΔE ≈ 7s
ΔE = hγ / Tlab = 8.4 · 10 -16 eV
ΔEν = Δm² /2 M = 3.1 · 10 -16 eV
With M =141 amu, γ = 1.43,
 Δm²12 = 2.20(2)· 10-4 eV2
With q13=0
With q13 non zero
 Δm²12 = 8· 10-5 eV²
 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
•Other suggestions:
•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 b+ channel
(c.f. V.I Isakov)
Can data of stored and implanted ions be compared?
P.A. Vetter et al (2008):
arXiv: 0807.0649
Implantation of 142Pm in a lattice
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 b+ 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