Bulletin of the American Physical Society
51st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 65, Number 4
Monday–Friday, June 1–5, 2020; Portland, Oregon
Session H07: Searches for Electric Dipole Moments and Discrete Symmetry ViolationsLive
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Chair: Eric Norrgard, NIST Room: E145-146 |
Wednesday, June 3, 2020 10:30AM - 10:42AM Live |
H07.00001: The Advanced ACME Search for the Electron Electric Dipole Moment Cole Meisenhelder, Daniel Ang, James Chow, David DeMille, John Doyle, Gerald Gabrielse, Zhen Han, Bingjie Hao, Peiran Hu, Nicholas Hutzler, Daniel Lascar, Siyuan Liu, Takahiko Masuda, Cristian Panda, Noboru Sasao, Satoshi Uetake, Xing Wu, Koji Yoshimura Searches for the electron electric dipole moment (eEDM) serve as powerful tests of physics beyond the standard model, probing for high energy time-reversal violating interactions. In 2018 the ACME collaboration reported a measurement of the eEDM which set a new limit of $|d_e|<1.1\times10^{-29}\ \textup{e}\cdot \textup{cm}$ (\textit{Nature}, \textbf{562} (2018) 355-360). Work is currently underway on a new Advanced ACME search with the goal to realize an order of magnitude improvement in experiment sensitivity. This new measurement will rely upon a number of statistical upgrades and a reduction in systematic errors due to known sources. In order to improve the statistical sensitivity of the experiment we are implementing new techniques to increase the flux of our ThO molecular beam, improve our detectors, and to increase the experiment precession time. Potential sources of systematic error have been studied and we plan to further suppress these effects through a new mag [Preview Abstract] |
Wednesday, June 3, 2020 10:42AM - 10:54AM Live |
H07.00002: New H-state lifetime measurement for the ACME electron EDM search Daniel Ang, James Chow, David DeMille, John Doyle, Gerald Gabrielse, Zhen Han, Bingjie Hao, Peiran Hu, Nicholas Hutzler, Daniel Lascar, Siyuan Liu, Takahiko Masuda, Cole Meisenhelder, Cristian Panda, Noburo Sasuo, Satoshi Uetake, Xing Wu, Koji Yoshimura The search for an electron electric dipole moment (EDM) probes physics beyond the Standard Model at high energy. The ACME II experiment recently set the most stringent limit on the electron EDM, $|d_e|<1.1\times10^{-29}~e \cdot cm$ (Nature 562 (2018), 355-360). The next generation of the experiment is now being developed. A major improvement in statistics can be obtained if the spin precession time is extended to near the natural lifetime of the H$^3\Delta_1$ state of the thorium monoxide (ThO) molecule, which is the EDM experimental state. Here we report recent progress in measuring the lifetime of the H-state using a cold molecular beam of ThO. We find that the lifetime is significantly longer than spin precession time $\tau$ used in ACME II, allowing for the possibility of increasing $\tau$ by a factor of $\approx$5 in the next generation of ACME. Together with other improvements, this provides us with a path towards an order of magnitude statistical improvement. [Preview Abstract] |
Wednesday, June 3, 2020 10:54AM - 11:06AM Live |
H07.00003: New techniques for a measurement of the electron electric dipole moment Chris Ho, Jack Devlin, Isabel Rabey, Pauline Yzombard, Jongseok Lim, Sidney Wright, Noah Fitch, Ed Hinds, Mike Tarbutt, Ben Sauer The search for the electric dipole moment of the electron (eEDM) is one of the most stringent tests for CP-violating physics beyond the Standard Model. The most sensitive searches for the eEDM use heavy polar molecules. We report on a series of new techniques that have improved the statistical sensitivity of the YbF eEDM experiment. We have increased the number of molecules participating in the experiment by an order of magnitude using a carefully designed optical pumping scheme. We have also increased the detection efficiency of these molecules by another order of magnitude using an optical cycling scheme. In addition, we show how to destabilise dark states and reduce backgrounds that otherwise limit the efficiency of these techniques. Together, these improvements allow us to demonstrate a statistical sensitivity of $1.8 \times 10^{-28}$ e cm after one day of measurement, which is 1.2 times the shot-noise limit. This will allow us to measure the eEDM at the $10^{-29}$ e cm level with 100 days of data. These techniques are also applicable to other precision measurements using molecules. [Preview Abstract] |
Wednesday, June 3, 2020 11:06AM - 11:18AM Live |
H07.00004: Towards a cold and intense beam of BaF molecules for an eEDM measurement Parul Aggarwal, Yanning Yin, Kevin Esajas, Steven Hoekstra Permanent electric dipole moments are signatures of time-reversal and parity violation, which acts as a sensitive probe of physics beyond the Standard Model. Within the NL-eEDM collaboration, we plan to measure the electron EDM using a cold, intense beam of barium monofluoride (BaF) molecules. Key to the increased sensitivity of our experiment is an increase in the coherent measurement time. This will be achieved by combining the intense beam created by a cryogenic buffer gas source, which typically has a velocity of 180-200 m/s, with a traveling-wave Stark decelerator. We plan to reduce the beam velocity to 30 m/s for the final measurement. In this talk, we will present the initial results obtained for the deceleration of SrF for this combination. [Preview Abstract] |
Wednesday, June 3, 2020 11:18AM - 11:30AM Live |
H07.00005: Towards a More Sensitive Measurement of the Atomic Electric Dipole Moment of Radium-225 Roy Ready Permanent atomic electric dipole moments (EDMs) violate parity (P), time reversal (T), and combined charge-conjugation and parity transformation (CP) under CPT symmetry. The EDM observable is enhanced in large-Z atoms with octupole-deformed nuclei like Radium-225. In the Ra EDM experiment, radium atoms are vaporized, slowed, trapped, and transported between two high voltage electrodes. The first-generation Radium-225 EDM upper limit results were measured in 2014 and 2015. For the imminent second-generation measurements, we increased the applied electric field by using a pair of meticulously conditioned niobium electrodes. The electrodes and several complementary upgrades will help improve our sensitivity by up to two orders of magnitude. Additionally, the Facility for Rare Isotope Beams (FRIB) is expected to produce Radium-225 when it is fully operational. We are making early progress in characterizing our ability to efficiently extract FRIB-harvested radium using stable surrogate isotopes. [Preview Abstract] |
Wednesday, June 3, 2020 11:30AM - 11:42AM Live |
H07.00006: Laser-cooled polyatomic molecules for improved electron electric dipole moment searches Zack Lasner, Benjamin Augenbraun, Alexander Frenett, Hiromitsu Sawaoka, Calder Miller, Zhijing Niu, John Doyle Polyatomic molecules are promising for searches for beyond-the-Standard-Model physics due to their doubly-degenerate vibrational modes with nuclear orbital angular momentum. For example, YbOH has been identified as a species for the next generation of electron electric dipole moment (eEDM) searches [Phys. Rev. Lett. 119, 133002]. We report direct laser cooling of YbOH to $<600$ $\mu$K via magnetically-assisted Sisyphus cooling. This bound is limited by experimental resolution and corresponds to an increase in phase-space density by $>6\times$. We construct a model with a single free parameter that shows excellent agreement with observations, and predicts that cooling to $~10 \mu$K already occurs. Further cooling and capture in a magneto-optical trap (MOT) of YbOH molecules will require increasing the number of photons scattered before an electronically excited molecule decays into a vibrationally dark state. Spectroscopic searches for vibrational dark states are currently underway. We also report on progress toward slowing molecules to near the capture velocity of the MOT using only a few scattered photons via Zeeman-Sisyphus slowing with superconducting magnetic stages, thus significantly reducing the number of vibrational repumpers needed. [Preview Abstract] |
Wednesday, June 3, 2020 11:42AM - 11:54AM Not Participating |
H07.00007: Towards Generation II Measurement of the Electron's Electric Dipole Moment with Trapped HfF+ Tanner Grogan, Tanya Roussy, Yuval Shagam, Kia Boon Ng, Noah Schlossberger, Sun Yool Park, Madeline Pettine, Antonio Vigil, Jun Ye, Eric Cornell Searches for the electron's electric dipole moment (eEDM) offer a low energy window into the matter-antimatter asymmetry in the universe. Trapped molecular ions have proven to be an effective platform for measuring the eEDM since they can be interrogated for long times [1]. We have recently enhanced our eEDM measurement sensitivity with HfF+ by achieving second-scale coherence times and increasing the count rate to hundreds of ions per shot while detecting at the quantum projection noise (QPN) limit [2]. We discuss progress towards the next eEDM measurement and challenges posed by our newly developed measurement scheme. \newline \newline [1] W. B. Cairncross, D. N. Gresh, M. Grau, K. C. Cossel, T. S. Roussy, Y. Ni, Y. Zhou, J. Ye, E. A. Cornell, Phys. Rev. Lett. 119, 153001 (2017). \newline \newline [2] Y. Zhou, Y. Shagam, W. B. Cairncross, K. B. Ng, T. S. Roussy, T. Grogan, K. Boyce, A. Vigil, M. Pettine, T. Zelevinsky, J. Ye, E. A. Cornell, Phys. Rev. Lett. (In Press). arXiv: 1907.03413. [Preview Abstract] |
Wednesday, June 3, 2020 11:54AM - 12:06PM Not Participating |
H07.00008: Spectroscopy of ThF$^{\mathrm{+}}$ in aim of a new eEDM measurement with trapped molecular ions Noah Schlossberger, Kia Boon Ng, Sun Yool Park, Yan Zhou, Tanya Roussy, Tanner Grogan, Yuval Shagam, Antonio Vigil, Madeline Pettine, Jun Ye, Eric Cornell A measurement of the electric dipole moment of the electron (eEDM) can constrain beyond-standard-model physics. Our group at JILA has measured the eEDM to a precision of 1.3e-28 e cm [1]. While a second generation experiment with technological and measurement scheme improvements is underway, we are developing a third generation experiment aimed at increasing the sensitivity to the eEDM with several key improvements: (i) a new molecular ion species, ThF$^{\mathrm{+}}$, which has an eEDM-sensitive ground state and an effective electric field of 38 GV/cm [2], and (ii) a new trap structure allowing for continuous measurement. The first step in designing this experiment is understanding the energy structure of our molecule. In this talk we discuss recent ThF$^{\mathrm{+}}$ spectroscopic results and their implications on the upcoming third generation measurement. [1] Cairncross, W. B. et. Al. Phys. Rev. Lett. 119, 15 (2017), 153001. [2] Skripnikov, L. V., and A. V. Titov. Phys. Rev. A 91.4 (2015): 042504. [Preview Abstract] |
Wednesday, June 3, 2020 12:06PM - 12:18PM |
H07.00009: Rotational Cooling in a Time-Reversal Symmetry Violation Molecular Beam Experiment Konrad Wenz, Michael Aitken, Olivier Grasdijk, Jakob Kastelic, Oskari Timgren, Tristan Winick, Trevor Wright, David DeMille, David Kawall, Steve Lamoreaux, Tanya Zelevinsky Our experiment is designed to search for time-reversal symmetry violation in a thallium nucleus by measuring its Schiff moment (SM) in thallium fluoride (TlF) molecules. Interrogating a cold molecular beam and manipulating quantum states of the molecule using optical and microwave transitions are the first steps that have to be undertaken in the experiment. A cold beam of TlF is acquired through a cryogenic buffer gas beam source where we ablate a solid TlF target in a neon-filled chamber and obtain molecules with a rotational temperature of 7K. In order to measure SM with high precision, we need to first bring as many molecules as possible to a single quantum state. After assembling the first portion of the setup, we characterized the molecular beam and performed spectroscopic measurements of TlF using a frequency-stabilized ultraviolet laser. Here, we present results of the first major part of the experiment - rotational cooling. This procedure allows us to bring the majority of molecules to a single hyperfine Zeeman sublevel in the ground rotational state manifold with the use of a single laser and a pair of microwave beams. [Preview Abstract] |
Wednesday, June 3, 2020 12:18PM - 12:30PM Not Participating |
H07.00010: Spectroscopy of YbOH Isotopologues for New Physics Searches. Nickolas Pilgram, Arian Jadbabaie, Yi Zeng, Timothy Steimle, Nicholas Hutzler Heavy polar molecules act as a powerful probe of physics beyond the standard model due to their high sensitivity to charge parity violating electromagnetic moments. The polyatomic molecule YbOH is a promising candidate for new physics searches in both the leptonic sector, via a search for the electron electric dipole moment (eEDM) in the $^{174}$YbOH isotopologue, and the hadronic sector, via a search for the nuclear magnetic quadrupole moment (nMQM) of the Yb nucleus in the $^{173}$YbOH isotopologue. In preparation for measurements of the eEDM and nMQM, we have measured the $\tilde{A}^2\Pi_{1/2}(0,0,0)-\tilde{X}^2\Sigma^+(0,0,0)$ transition of a molecular beam sample of YbOH at near-linewidth resolution and modeled the corresponding fine and hyperfine splittings for all isotopologues. This builds on the previous optical study of the $^{174}$YbOH and $^{172}$YbOH and microwave study of $^{174}$YbOH. An optimized set of fine and hyperfine parameters of the $\tilde{X}^2\Sigma^+(0,0,0)$ and $\tilde{A}^2\Pi_{1/2}(0,0,0)$ states, were obtained via a nonlinear least squares fit to the observed transition wavenumbers. The estimated hyperfine parameters of the odd isotopes of YbOH are compared to the corresponding parameters of isoelectronic YbF, as well as to ab initio calculations. [Preview Abstract] |
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