Laser Cooling of Ra ions for Atomic Parity

Laser Cooling of Ra ions for Atomic Parity Violation CERN-INTC-2017 -069 CERN, June 27, 2017 Lorenz Willmann

CERN-INTC-2017 -069

Atomic Parity Violation THE WEINBERG ANGLE

Atomic parity violation (APV) sin 2(θW) = (1 – (MW/MZ)2) + rad. corrections + New Physics Standard Model Kumar, Marciano, Annu. Rev. of Nucl. Part. Sci. 63, 237 (2013) Davoudiasl, Lee, Marciano, Phys. Rev. D 89, 095006 (2014); Phys. Rev. D 92, 055005 (2015)

Ra+ Cs F. Maas, PSI 2016

Cs Atomic Parity Violation Stark induced forbidden transition (C. Wieman et al. 1985 -1996)

Experimental Method SINGLE ION APV

Weak Interaction in Atoms Interference of EM and Weak interactions E 1 PNC = Kr Z 3 Qw = Kr Z 3 (- N + Z (1 -4 sin 2 θW)) Measurement Heavy System Atomic Theory

Scaling of the APV Kr relativistic enhancement factor increase faster than Z 3 (Bouchiat & Bouchiat, 1974) Z 3 K r + Ra effects larger by: 20 (Ba+) 50 (Cs) Enhancement Ra+ Ca+ Sr+ Z 3 Ba+ L. W. Wansbeek et al. , Phys. Rev. A 78, 050501 (2008) Atomic Number Relativistic coupled-cluster (CC) calculation of E 1 APV in Ra+ E 1 APV = 46. 4(1. 4) · 10 -11 iea 0 (−Qw/N) (3% accuracy) Other results: 45. 9 · 10 -11 iea 0 (−Qw/N) (R. Pal et al. , Phys. Rev. A 79, 062505 (2009), Dzuba et al. , Phys Rev. A 63, 062101 (2001). )

Experiment requires Trapping Differential Light shift Energy splittings not to scale N. Fortson, Phys. Rev. Lett. 70, 2383 -2386 (1993)

Previous Work TRAPPING RA ION

Radium Isotopes + 12 C ARa 206 Pb beam target TRIμP separator To RFQ (Paul trap) Rate after TI 225 Ra extraction from 229 Th source (ANL) Long lived 229 Th source in an oven (TRI P) Other Isotopes Online production at accelerator facilities e. g. TRI P ( flux > 105/s) (until 2013) ISOLDE ( flux < 107/s) ΔN <10 Thermal ionizer TRI P@KVI 12 C + (218 -A) n Sources or fragmentation 206 Pb

Trapped Ra+ Spectroscopy Radiofrequency Quadrupole (RFQ) 7 P 3/2 7 P 1/2 708 nm 1079 nm 468 nm 7 S 1/2 Level Scheme of Ra+ 6 D 5/2 6 D 3/2

Hyperfine Structure of 6 d 2 D 3/2 in + Ra 3, 5 σ Probe of atomic wave functions at the origin Probe of atomic theory & size and shape of the nucleus O. O Versolatao et. al. , Phys. Lett. A 375 (2011) 3130– 3133 G. S. Giri et al. Phys. Rev. A 84, 020503(R) (2011) [10] B. K. Sahoo et al. Phys. Rev. A, 76 (2007) B. K. Sahoo et al. Phys. Rev. A, 79, 052512 (2009)

Summary Ra+ Measurements Hyperfine Structure: Atomic wave functions at the origin Isotope Shifts: Atomic theory & size and shape of the nucleus State lifetime: Probe of S-D E 2 matrix element agreement with atomic structure calculations at % level

Atomic Properties COMPLEMENTARY RADIUM EXPERIMENTS

Activity at CERN/ISOLDE

mu. X@PSI Radium Charge Radium Beamtime to improve sensitivity of muonic x-ray measurements this summer

Ba+ Atomic Parity Violation BARIUM ION

Hyperbolic Single Ion Trap 10µm

Hyperbolic Paul trap 5 mm 2 P 2 P 3/2 1/2 494 nm 2 S 1/2 650 nm 138 Ba+ VRF 2 D 2 D 5/2 3/2 21

2 D 2 D 5/2 3/2 rs 650 nm laser frequency (MHz) D Ion trap EM CC 1/2 138 Ba+ se 2 S 650 nm La 494 nm PM T Detection 2 P 2 P 3/2 1/2

Importance of Line Shape |2 P 1/2 �|4 Γ 1 Optical Bloch equation � |3 �Δ Δ 1 3 level example γ |2 S 1/2 � Γ 2 2 Ω 1 |2 � |1 � γc γ |8 � |7 � |6 � |5 |2 D 3/2 � � Ba+ Ω 1, Ω 2 Rabi frequencies (laser power) Γ = Γ 1 + Γ 2 Γ/2 γ= relaxation rate Δ 1, Δ 2 laser detunings γc laser linewidth decoherence rate

Transition frequencies 2 P 2 P Ba+ 3/2 1/2 650 nm 494 nm 2 D 2 D 5/2 3/2 2 S 1/2 494 nm laser detuning varied 650 nm laser intensity varied Frequency 650 nm laser − 461 311 000 MHz • Fitted with optical Bloch equation model • Extract transition frequencies with 100 k. Hz accuracy Dijck et al. , Phys. Rev. A 91, 060501(R) (2015)

Transition frequencies 2 P 2 P Ba+ 3/2 1/2 650 nm 494 nm 2 D 2 D 5/2 3/2 2 S 1/2 494 nm Light shift? 650 nm laser intensity varied • One-photon peak frequency (MHz) 650 nm Correction in transition frequencies for Ω 2 dependent shift consistent with 2° rotation of B-field B-fi 2° ted rota 879. 5 879. 0 878. 5 461 311 878. 0 Expected 0 Frequency 650 nm laser − 461 311 000 MHz • Fitted with optical Bloch equation model • Extract transition frequencies with 100 k. Hz accuracy 1 2 Power 650 nm laser 3 (Ω 22 / 4 2 Ω 2, sat ) Dijck et al. , Phys. Rev. A 91, 060501(R) (2015) 5

Atomic Parity Violation SUMMARY

Accuracy of Single Ion Experiment If coherence time can be fully exploited

Ratio measurement Insensitivity of Ratio of measurements of E 1 APV for isotopes to atomic structure. V. A. Dzuba, V. V. Flambaum, and I. B. Khriplovich, Z. Phys. D, 1, 243 (1985) Best case scenario: For radium a wide range of isotopes is available

Laser Cooling of Ra ions for Atomic Parity Violation: Ba+ • Developing experimental setup • Atomic properties determination • Light shifts and Line shapes Ra+ • • Frequency 650 nm laser − 461 311 000 MHz Atomic Properties from online produced radium Trapping and laser spectroscopy done at TRI P Activity on Ra+ colinear spectroscopy (ISOLDE) Muonic Radium experiments for charge radius ISOLDE • • • Ion trapping permits access to many transitions Laser cooling for precision Availability of a large range of Ra isotopes Lab with experience of precision lasers experiments at accelerators Building up of a collaboration