Erlangen 2022 – scientific programme

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MO: Fachverband Molekülphysik

MO 17: Precision

MO 17.3: Talk

Thursday, March 17, 2022, 11:00–11:15, MO-H6

Electrostatic lens for ThO molecules in the ACME III electron EDM search — •Xing Wu^1,2, Daniel Ang², David DeMille¹, John Doyle¹, Gerald Gabrielse³, Zhen Han¹, Bingjie Hao³, Ayami Hiramoto⁴, Peiran Hu¹, Daniel Lascar³, Zack Lasner², Siyuan Liu³, Takahiko Masuda⁴, and Cole Meisenhelder² — ¹The University of Chicago — ²Harvard University — ³Northwestern Unviersity — ⁴Okayama University

Measurements of the electron electric dipole moment (eEDM) using atoms and molecules shed light on T-symmetry violating new physics beyond the Standard Model. The best upper limit on the eEDM was recently set by the ACME collaboration: |d_e|<1.1×10⁻²⁹e·cm, using a cold beam of thorium monoxide (ThO) molecules. This result significantly constrains T-violating new physics in the 1∼10 TeV range and above. The next generation of ACME aims to improve the sensitivity to d_e by another order of magnitude. A molecular lens is used to focus, into the EDM measurement region, beams of ThO molecules that have been prepared in the highly polarizable Q state. Our lens system requires several new features: 1) a new, spatially compact rotational cooling scheme which we demonstrated to work with efficiency near its theoretical limit; 2) a STIRAP process to transfer molecules into and out of the Q state, demonstrated with 80% total efficiency; and 3) an electrostatic hexapole lens operated at ±23kV, demonstrated to enhance molecular signal by 16 times relative to an unfocused molecular beam.