1. 1 m Tungsten Carbide Spectroscopy for electron EDM Measurement Jeongwon Lee June 23, 2011 Jinhai Chen, and Aaron E. Leanhardt Department of Physics, University of Michigan 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011

2. E lab [1] B.C. Regan, E.D. Commins, C.J. Schmidt & D. DeMille [PRL 88, 071805 (2002)] [2] J.J. Hudson, D.M. Kara, I.J. Smallman, B.E. Sauer, M. R. Tarbutt & E.A. Hinds [Nature 473, 493-496 (2011)] Effective Electric Field : E-field seen by e - inside atoms and molecules - Maximum E lab ~ 10 5 V/cm -High Z atoms : E eff ~ 10 7 V/cm Upper Limit from Tl expt.[1] : |d e | < 1.6 x 10 -27 e*cm [~10 -18 Debye] -Heavy Polar Molecules : E eff ~ 10 10 V/cm Upper Limit from YbF expt.[2] : |d e | < 10.5 x 10 -28 e*cm Heavy Polar molecules for e - EDM search

3. E lab 3 Δ 1 ground state of WC molecules  el E lab 2  m B + 2d e E eff 2  m B - 2d e E eff Systematic Error Rejection 1.μ m Less Sensitive to B field 2. Small Ω doublet splitting => Efficient Zeeman Shift Cancellation B 3 Δ 1 State Molecules: JILA: HfF +, ThF + R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 (2004). Harvard/Yale : ThO A. Vutha, et. al., J. Phys. B. 43, 074007 (2010). Michigan: WC J. Lee, R. Paudel, E. Meyer, J. Bohn, and A. Leanhardt, J. Mod. Opt. 56, 2005 (2009). 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011

4. Previous Studies on WC Progress in WC spectroscopy 3 Δ 1 ground state Characterization [1] Rotationally Resolved bands [1] 17500 ~ 23250 cm-1 Stark, Zeeman Spectroscopy in [17.6]2 <- 3 Δ 1 (1,0) band [2] Hyperfine Constants & Upper Limit for the Ω doublet Constants in [17.6]2 <- 3 Δ 1 (1,0) band [2] Our Current Work Optimization of Flux & Rotational Temperature of the Beam Hyperfine Constants & Upper Limit for the Ω doublet Constants in [20.6]2 <- 3 Δ 1 (4,0) band [1] S.M. Sickafoose, A.W. Smith & M.D. Morse [JCP 116, 993 (2002)] [2] Private Comm. with T.C. Steimle [to be published in JCP] 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011

5. Pulse WC supersonic beam apparatus Pulse Valve 485nm diode laser (perpendicular to molecular beam) Tungsten Rod Nd:YAG Laser PMT Vacuum Pump 90% Argon + 10% CH4 W + CH 4  WC + 2H 2 75 cm Pressure ~10 -6 Torr 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011

6. Tungsten Carbide R(1) lines LIF spectroscopy of R(1) line of [20.6] 2 <- X 3 Δ 1 (4,0) band system 182 W 12 C, R(1) ~10MHz X 3  1 [20.6]  =2 v’’=0 v’=0 v’=1 v’=2 J’’=1 J’’=2 J’’=3 J’=3 J’=4 J’=2 v’=3 v’=4 R(1) line Ro-vibrational ground state => EDM state 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011 PRQ cm -1

7. Hyperfine Structure of 183 W 12 C ( I = ½ ) 183 W 12 C R(1) 183 W 12 C R(2) ab c ca 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011

8. Tungsten Carbide Ω Doublet (Under Progress) Higher J line measurements required for tighter constraints on. 182 W 12 C, R(1) 182 W 12 C, Q(2) For X 3 Δ 1 state 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011 R(1) Q(2) MHz

9. Summary E eff estimation Zeeman Shift cancellation 66 th International Symposium on Molecular Spectroscopy, June 20-24, 2011

10. Thank You Top Row: Jinhai Chen, Aaron Leanhardt, Emily Alden Bottom Row: Kaitlin Moore, Yisa Rumala, Chris Lee, Erika Etnyre

11. e - EDM Search Outlook d e [e*cm] 10 -38 10 -28 10 -30 10 -32 10 -34 10 -36 10 -40 SUSY Multi-Higgs Left-Right 10 -24 10 -26 |d e | < 1.6 x 10 -27 e*cm [~10 -18 Debye] E.D. Commins Tl Exp. Limit [PRL 88, 071805 (2002)] |d e | < 10 -29 e*cm / day 1/2 Currently: Detection of WC molecules with 10Hz Goal: Continuous Beam of WC to achieve 10kHz Sensitivity Goal: |d e | < 10 -29 e*cm / day 1/2 Theoretical calculations: E eff ~ 6 x 10 10 V/cm Necessary spin coherence time:  ~ 3 ms Necessary counting statistics: dN/dt ~ 3*10 6 s -1 Standard Model

12. General Considerations Potential Signal EDM Shift: ~30 mHz [d e ~ 10 -27 e*cm, E eff ~ 60 GV/cm] Potential Noise Zeeman Shift: ~30 mHz [B ~ 1 μG, μ m ~ 0.01*μ B ] (v x E lab )/c 2 effects: ~30 mHz [v ~ 300 m/s, E lab ~ 300 V/cm] Potential Sensitivity Resolution: ~30 mHz/√Hz [dN/dt ~ 3*10 6 s -1,  ~ 3 ms]

13. Sensitivity Goal Current Status (future plan) -Continuous Beam - with E eff ~ 5 x 10 10 V/cm,  ~ 3 ms, and one day of integration (T~10 5 s), => e-EDM detection limit : |d e | < 1 x 10 -27 e*cm (1 x 10 -28…-29(?) e*cm) - Collection solid angle - Frank-Condon Factor - Quantum efficiency EDM Shift : Frequency Resolution : VS.

14. 2 nd Generation WC apparatus: Continuous WC supersonic beam Tungsten Filament Nozzle Skimmer Optical Spectroscopy Chamber - 10~100 fold increase in flux expected, compared to the pulse beam - Mass spectroscopy performed on W and WC - LIF spectroscopy performed on Tungsten atoms - LIF spectroscopy of Tungsten Carbide (under progress)