Muon Spectroscopy WS, Villigen Nuclear charge radii measurements by collinear laser spectroscopy and Penning trap g-factor experiments: The need for absolute charge radii Collinear laser spectroscopy studies g-factors of bound electrons in HCI Klaus Blaum Oct 21th, 2016

Laser spectroscopy studies Charge radii Laser spectroscopy studies CERN, Darmstadt, Leuven, Liverpool, Manchester, MPIK

Principle of collinear laser spectroscopy electrostatic deflection charge exchange cell (Na) ion beam Ekin<60 keV electrostatic lenses for retardation excitation & observation reg. + laser beam fixed frequency + + fine 250 25 Mg HFS of A(S1/2) = 596.5(5) MHz 300 350 fine Doppler tuning voltage (V) 400 photons D 6.5 o o photo multiplier

HFS and Isotope shift Experimental spectrum Isotope 1 Isotope Shift := Frequency difference in an electronic transition between two isotopes Isotope 2 J=3/2 J=1/2 Experimental spectrum

HFS and Isotope shift Isotope 1 Isotope Shift := Frequency difference in an electronic transition between two isotopes Isotope 2

Isotope shift Mass Shift Field Shift Isotope 1 Isotope 2 IS E r p s (center-of-mass motion) Field Shift (finite size) r E s p |IS|, GHz Z

Laser spectroscopy of radionuclides Pulsed Resonance Ionization (RIS) Collinear Spectroscopy (+ cw RIS) Low-Medium Resolution, High Efficiency Medium-High Resolution, Lower Efficiency Specialized Techniques High Resolution + High Efficiency Courtesy: W. Nörtershäuser H.-J. Kluge and W. Nörtershäuser, Spectrochim. Acta B, 58 (2003). http://www.kernchemie.uni-mainz.de/lasers

Isotope shifts in Cu and Ga COLLAPS (ISOLDE) 5/2 3/2 1/2 Spin 1/2 col. Spin 3/2, 5/2 inversion π p3/2(f5/2)2 π (p3/2)3 Emptying of p3/2 Sudden nuclear structure changes between N=40 and N=50 71,73,75Cu: PRL 103, 142501 (2009); 67-81Ga: PRL 104, 252502 (2010); 102-132Cd: PRL 110, 192501 (2013)

Charge radii in Cu and Ga Changes in mean-square charge radii for the Cu isotopes and neighboring isotopic chains. The other isotopic chains are offset by the nominal differences in absolute mean-square charge radii from [42] without further consideration of the associated large and model-dependent uncertainties. Cu results based only on theMCDHF calculations, without alteration of Mk to reproduce the muonic atom data are shown as the black dashed line. Systematic uncertainties for Cu and Ga [43] are represented by the shaded lines above and below the respective trends. Courtesy: M. Missell Cu: PRC 93, 064318 (2016) Ga: PRC 86, 044329 (2012)

The Ca radii puzzle Rch(40Ca) = 3.478(2) fm RFQ Rch(40Ca) = 3.478(2) fm R. Garcia-Ruiz et al., Nature Physics (2016)

g-factors and fundamental tests The need of absolute charge radii for g-factor measurements * In collaboration with Ch. H. Keitel (MPIK), W. Quint (GSI), G. Werth (Mz)

Quantum-ElectroDynamics (QED) QED describes the quantum interaction of light (photons) and matter (charged particles) through a series of simple fundamental interaction processes depicted by Feynman diagrams Calculated values are in impressive agreement with experimental results QED is our best tested theory in weak fields Richard P. Feynman Highly charged ions However: Lack of tests in extreme situations

The g-factor g(12C5+) g(28Si13+) [J. Zatorski et al., 2011] K. Pachucki et al., Phys. Rev. A 72, 022108 (2005) [J. Zatorski et al., 2011]

Measurement principle Measurement of the free cyclotron frequency to determine the magnetic field: B Measurement of the Larmor frequency in a well-known magnetic field: B Measured by independent precision experiments has to be determined Experimental conditions: Cryogenic temperatures (4.2K) Non-destructive ion detection Vacuum better than 10-16 mbar less than 20 gas atoms in the trap volume !

g-factor resonance of a single 28Si13+ ion Uncertainty on electron mass got reduced by a factor of 13 using 12C5+. Most stringent test of BS-QED in strong fields. Theory colleagues: Harman, Keitel, Zatorski S. Sturm et al., Phys. Rev. Lett. 107, 023002 (2011) A. Wagner et al., Phys. Rev. Lett. 110, 133003 (2013) Experiment limited by uncertainty of electron mass Theory limited by nuclear structure effects gexp = 1.995 348 958 7 (5)(3)(8) gtheo= 1.995 348 958 0 (17)

g factor results The current measurement is testing QED theory at the level of 1.4∙10-7 Higher order contributions to two-loop theory are relevant for the first time Nuclear size effect tested for the first time, nuclear charge radius extracted: <r2>1/2 = 3.12 (15) fm Vacuum polarization tested Measurements of other g factors will allow further tests Theory will provide more accurate results in the future Rrms(238U) = 5.8604(23) fm T. Beier, Phys. Rep. 339, 79 (2000) our measurement

What comes next? a ALPHATRAP: A high-precision Penning- trap setup at MPIK for HITRAP Production of HCI 208Pb77+,81+ Larmor-to-cyclotron frequency ratio measurement in a double Penning trap yields dg/g ≈ 10-12 Experiment and theory provide stringent test of BS-QED and FSC a

Thanks a lot for the invitation Conclusion There is a strong need for absolute charge radii measurements by muon spectroscopy! Thanks a lot for the invitation and your attention! Email: klaus.blaum@mpi-hd.mpg.de WWW: www.mpi-hd.mpg.de/blaum/ Max Planck Society Adv. Grant MEFUCO Helmholtz Alliance IMPRS-PTFS