Precision mass measurements for fundamental studies

Tommi EronenMax-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

INVARIANCE THEOREM

SIDEBANDFREQUENCY

TOF-ICR methodFor nuclei having T1/2 > 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 superallowedbeta emitters

Superallowed beta emitters

NEED Q-values at 100-eV level

• 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

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 transitionscontribute

Superallowed beta emitters - QEC

Bold: Contributes to worldaverage 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 valuesThe influence of JYFLTRAP QEC value measurements.

Ft-value error budget

Most precise

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?Top-row unitarity requirement:

Courtesy of J.C. Hardy

With H&T corrections

Superallowed outlook

• QEC values: 14O, heavier A > 62• Branching ratios of T=-1 nuclei• Half-lives• Theoretical corrections (DC) A > 62

QEC values of mirrordecays

• T=1/2 decays• Fermi + Gamow-

Teller– Need mixing ratio

• Currently 5 well known decays

O. Naviliat-Cuncic and N. Severijns, PRL 102, 142302 (2009)

Mirror decays

Error contributions

Vud from different sources

Mirror decays – TODO

• F/GT ratios; LPC-trap, MOTs, WITCH-trap...• DR

V 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...

SMILETRAPJYFLTRAPSHIPTRAPLEBITTRIGATRAPCanadian PTISOLTRAPFSU

Detection of 0nbb

• 2nbb is (huge) background• 76Ge

– Heidelberg-Moscow claim– GERDA, MAJORANA experiments

T1/2≈1019y T1/2>1025y

Penning trap mass spectrometry:

• Energy of the endpoint!

Heidelberg-Moscow

76Ge

GERDA has some news soon...

Neutrinoless double-electron capture

• Predicted half-lives very long, > 1026 y, not seen yet• Resonant enhancement!

From Penning trap

mass spectrometry!

KK, KL, LL, ..

0+ to 0 + transitions between nuclear ground states

• |M| =3 for 0+ → 0+

T1/2 (0+→0+) ~ 31024 y for |m2EC|=1 eV

multiple-resonance phenomena in 156Dy

S. Eliseev et al., PRC 84, 012501R (2011)

• Tritium beta decay:

• Neutrino with mass:– Endpoint shifted– Spectrum shape changed

• Current knowledge:

Tritium (3H) Q-value

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-trap2014 (?)

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->)

position-sensitive detector

Penning trap Phase imaging

B

2D delay-line MCP

PI-ICR method

36Eliseev et al., PRL 110, 082501 (2013)

37

On the Way to Mass Measurements

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!