Precision mass measurements
for fundamental studies
Tommi Eronen
Max-Planck-Institut für Kernphysik
Heidelberg, Germany
Outline
• Penning trap mass spectrometry
– Q = mparent – mdaughter
• Masses for CKM unitarity tests...
– Superallowed beta decay
– Mirror beta decay
• Masses for neutrino studies..
– Double beta decay
– Double electron capture
– Tritium Q-value
Penning Trap Mass Spectrometry
Cyclotron frequency
Penning trap eigenfrequencies
SIDEBAND
FREQUENCY
INVARIANCE THEOREM
TOF-ICR method
For nuclei having T
1/2
> 10 ms
A/q doublets!
• Q-value measurements
– Special – mass doublets, e.g. 76Ge vs 76Se
– cancellation of systematic errors
– 10x better accuracy achieved
– Typical:
• q=1e, B=7T, m=100u with 10-9 precision -> Dm = 100 eV
• Absolute mass measurements – 10-7..8
QEC values of superallowed
beta emitters
Superallowed beta emitters
• Decays of nuclear 0 + → 0+
states, T=1
• Pure Fermi decays
• Simple decay matrix element
• Characterized with an ft value
– f stat. rate function; (f  QEC5)
– t partial half-life t1/2/b
NEED Q-values at 100-eV level
Testing the Standard Model
• Corrected value:
• Corrections about 1% [Towner and Hardy, Phys. Rev. C 77, 025501 (2008)]
• Cabibbo-Kobayashi-Maskawa quark mixing
matrix
• Quark-mass eigenstates
to weak eigenstates
Currently 13 transitions
contribute
Superallowed beta emitters - QEC
Bold: Contributes to world
average value (13)
Why so many JYFL points?
- Simultaneous production
- No chemical selection
Most recent QEC from JYFLTRAP
•
10C, 34Ar, 38Ca,
(revisited 46V)
T. Eronen et al., Phys. Rev. C 83, 055501 (2011)
Ft values
The influence of JYFLTRAP QEC value measurements.
Ft-value error budget
From J.C. Hardy, I.S. Towner, Phys. Rev. C 79, 055502 (2009)
Different dC
Towner & Hardy,
PRC 77, 025501 (2008).
Satula et al.,
PRL 106, 132502 (2011).
Liang et al.,
PRC 79, 064316 (2009).
Standard Model is still ok?
With H&T corrections
Top-row unitarity requirement:
Courtesy of J.C. Hardy
Superallowed outlook
•
•
•
•
QEC values: 14O, heavier A > 62
Branching ratios of T=-1 nuclei
Half-lives
Theoretical corrections (DC) A > 62
QEC values of mirror
decays
Mirror decays
• T=1/2 decays
• Fermi + GamowTeller
– Need mixing ratio
• Currently 5 well
known decays
O. Naviliat-Cuncic and N. Severijns, PRL 102, 142302 (2009)
Error contributions
Vud from different sources
Mirror decays – TODO
• F/GT ratios; LPC-trap, MOTs, WITCH-trap...
• DRV  theoretical calculations
• dNS - dC  measurements of heavy
isotopes + theory
• Measurements of t1/2, BR and QEC
Precision mass measurements for
neutrino physics
• Double b- decay
• Double electron capture
• Tritium Q-value for KATRIN spectrometer
Double beta decays
• Double b- decay (bb) and double-electron capture (2EC)
– two-neutrino mode (2nbb) and (2n2EC)
– neutrinoless mode (0nbb) and (0n2EC)
• Observation would prove thatn is a Majorana particle
• Conservation of total lepton number breaks
• Effective Majorana neutrino mass from half-life
double-electron-capture nuclides
double-beta-decay nuclides
Penning trap Q-value harvest...
SMILETRAP
JYFLTRAP
SHIPTRAP
LEBIT
TRIGATRAP
Canadian PT
ISOLTRAP
FSU
Detection of 0nbb
• 2nbb is (huge) background
• 76Ge
– Heidelberg-Moscow claim
– GERDA, MAJORANA experiments
T1/2>1025y
T1/2≈1019y
Heidelberg-Moscow
76Ge
GERDA has some news soon...
Neutrinoless double-electron
capture
• Predicted half-lives very long, > 1026 y, not seen yet
• Resonant enhancement!
KK, KL, LL, ..
0+ to 0 + transitions between
nuclear ground states
multiple-resonance phenomena in
156Dy
• |M| =3 for 0+ → 0+
T1/2 (0+→0+) ~ 31024 y
for |m2EC|=1 eV
S. Eliseev et al., PRC 84, 012501R (2011)
Tritium (3H) Q-value
• Tritium beta decay:
• Neutrino with mass:
– Endpoint shifted
– Spectrum shape changed
• Current knowledge:
KATRIN experiment
Endpoint of tritium beta spectrum
Electron neutrino mass with KATRIN:
• 10x better - sensitivity 0.2 eV
Goal with Penning traps:
• Improve 1.2 eV → 0.03 eV
T-3H Q-value measurements
THe-trap
2014 (?)
New technique for Penning trap
mass spectrometry
• Phase-Imaging motion detection
• Measure motion revolutions in the trap
– For n+ and n– Recipe:
• Excite the motion (dipolar RF E-field)
• Project to magnetron motion
• Count revolutions + phase of the last round
– Some x10 faster or more precise than TOF-ICR
Developed at SHIPTRAP by S. Eliseev et al. (2012->)
Penning trap
Phase imaging
position-sensitive detector
B
2D delay-line MCP
PI-ICR method
Eliseev et al., PRL 110, 082501 (2013)
36
On the Way to Mass Measurements
37
Summary
• Q-values from mass spectrometry for
– Testing the Standard Model
• Superallowed beta decays (some cases left to measure)
• Mirror decays (plenty of cases still to measure)
– Neutrino studies
• Neutrinoless double beta- decay
• Neutrinoless double electron capture
• New mass measurement techniques
Thank you for your attention!