390 likes | 505 Views
Precision mass measurements for fundamental studies. Tommi Eronen Max-Planck-Institut für Kernphysik Heidelberg, Germany. Outline. Penning trap mass spectrometry Q = m parent – m daughter Masses for CKM unitarity tests... Superallowed beta decay Mirror beta decay
E N D
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 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
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; (fQEC5) • 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 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? 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
Mirror decays • 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 – TODO • F/GT ratios; LPC-trap, MOTs, WITCH-trap... • RV theoretical calculations • NS - C 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 • Penning trap mass spectrometry: • Energy of the endpoint! T1/2>1025y T1/2≈1019y
76Ge Heidelberg-Moscow GERDA has some news soon...
Neutrinoless double-electron capture • Predicted half-lives very long, > 1026 y, not seen yet • Resonant enhancement! KK, KL, LL, .. From Penning trap mass spectrometry!
multiple-resonance phenomena in 156Dy • |M|=3 for 0+→ 0+ T1/2 (0+→0+)~ 31024 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:
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->)
B Phase imaging Penning trap position-sensitive detector 2D delay-line MCP
PI-ICR method Eliseev et al., PRL 110, 082501 (2013)
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