Bulletin of the American Physical Society
52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 66, Number 6
Monday–Friday, May 31–June 4 2021; Virtual; Time Zone: Central Daylight Time, USA
Session K03: Search for Beyond Standard Model Interactions ILive
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Sponsoring Units: GPMFC Chair: Ibrahim Sulai, Bucknell University |
Wednesday, June 2, 2021 10:30AM - 10:42AM Live |
K03.00001: A New Lifetime Measurement of the H3Δ1 state of Thorium Monoxide for the ACME electron EDM experiment Daniel G Ang, David P DeMille, John M Doyle, Zhen Han, Bingjie Hao, Ayami Hiramoto, Peiran Hu, Nicholas Hutzler, Daniel D Lascar, Zack Lasner, Siyuan Liu, Takahiko Masuda, Cole Meisenhelder, John Mitchell, Cristian D Panda, Noboru Sasao, Satoshi Uetake, Xing Wu, Koji Yoshimura, Gerald Gabrielse The electron electric dipole moment (EDM) is a powerful probe for new physics beyond the Standard Model. The ACME experiment measures the electron EDM by performing spin precession in the H$^3\Delta_1$ state of thorium monoxide. In 2018, the ACME II experiment set the most stringent upper limit on the electron EDM: $|d_e|<1.1\times10^{-29}\ \textup{e}\cdot \textup{cm}$ (\textit{Nature}, \textbf{562}(2018) 355-360). The next generation of the experiment is currently under development. We have recently performed a measurement of the lifetime of the H-state in a molecular beam, finding it to be $\sim$4.5 times longer than the precession time in the ACME II experiment. This allows us to increase the precession time in ACME III, significantly improving its statistical sensitivity to the electron EDM. Together with other improvements under development, this provides a path towards an order of magnitude statistical improvement in probing the electron EDM. |
Wednesday, June 2, 2021 10:42AM - 10:54AM Live |
K03.00002: Electrostatic lens for ThO molecules in the ACME III electron EDM search Xing Wu, Daniel G Ang, David P DeMille, John M Doyle, Gerald Gabrielse, Zhen Han, Bingjie Hao, Ayami Hiramoto, Peiran Hu, Nicholas Hutzler, Daniel D Lascar, Zack Lasner, Siyuan Liu, Takahiko Masuda, Cole Meisenhelder, John Mitchell, Cristian D Panda, Noboru Sasao, Satoshi Uetake, Koji Yoshimura 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: |de|<1.1×10-29 e·cm [1], 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 de by another order of magnitude. A molecular lens will be used to focus, into the EDM measurement region, beams of ThO molecules that have been prepared in the highly polarizable Q state. We present several new features of our lens system: 1) a new, spatially compact rotational cooling scheme which is 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 [2]; and 3) an electrostatic hexapole lens operated at +/-23kV. Our analysis indicates the molecular lens system should improve the EDM signal by over one order of magnitude relative to an unfocused molecular beam. We present progress towards implementing the full system. |
Wednesday, June 2, 2021 10:54AM - 11:06AM Live |
K03.00003: Projected Sensitivity of the JILA Gen. II eEDM Experiment Trevor Wright, Tanya Roussy, Kia Boon Ng, Noah Schlossberger, Sun Yool Park, Luke A Caldwell, Anzhou Wang, Antonio Vigil, Gustavo Santaella, Tanner Grogan, Yan Zhou, Yuval Shagam, Madeline Pettine, Jun Ye, Eric A Cornell A new limit on the permanent electric dipole moment of the electron (eEDM) will probe physics beyond the standard model and shed light on open questions such as the baryon asymmetry and dark matter. Our upcoming measurement of the eEDM uses a thermal cloud of HfF+ ions held in an RF trap, allowing us to leverage second-scale coherence times and the large internal electric fields present in polar molecules. This talk will detail the second generation experimental setup, and our analysis of roughly 40 hours of near quantum projection noise limited precision data to project the final sensitivity of our measurement. We expect to reach a statistical sensitivity of 30 μHz with 200 hours of data, and together with systematic evaluations, could potentially set a new limit on the eEDM with an uncertainty of less than 10-29 e cm at the 90% confidence interval. |
Wednesday, June 2, 2021 11:06AM - 11:18AM Live |
K03.00004: Progress on the JILA Gen. III eEDM Experiment Sun Yool Park, Kia Boon Ng, Noah Schlossberger, Anzhou Wang, Yan Zhou, Tanya Roussy, Trevor Wright, Luke A Caldwell, Tanner Grogan, Yuval Shagam, Antonio Vigil, Gus Santaella, Madeline Pettine, Jun Ye, Eric A Cornell The third generation (Gen. III) apparatus for the measurement of the electron electric dipole moment (eEDM) at JILA utilizes ThF+, rather than HfF+, because: (i) the eEDM sensitive state of ThF+ promises a longer coherence time (~ 20 seconds) [1,2], and (ii) its 50% larger effective electric field increases eEDM sensitivity [3,4]. The “conveyor belt” of 100 consecutive ion traps, named the Bucket Brigade (B.B.) will continuously load and read out ThF+, allowing for an increased duty cycle without compromising long interrogation times. In addition, the system will include cryogenics to further increase the coherence time. We are currently designing the prototype, a small-scale B.B. with only one ion trap. The scaled-down version will allow us to test out the ion translation, ion detection, and cryogenics as well as observe the 20-second coherence time. Here, we present the progress on the cryogenic design and ion optics for detection of the photodissociated products for the Gen. III eEDM experiment at JILA. |
Wednesday, June 2, 2021 11:18AM - 11:30AM Live |
K03.00005: Deceleration and trapping of SrF molecules using electric fields Parul Aggarwal Permanent electric dipole moments (EDMs) are signatures of time-reversal and parity violation, which acts as a sensitive probe of physics beyond the Standard Model (BSM). Within the NL-eEDM collaboration, we plan to measure the electron’s EDM using a cold, intense beam of barium fluoride (BaF) molecules. |
Wednesday, June 2, 2021 11:30AM - 11:42AM Live |
K03.00006: Toward Ultracold Polyatomic Molecules for Measuring the Electron's Electric Dipole Moment Benjamin Augenbraun, Zack Lasner, Alexander J Frenett, Hiromitsu Sawaoka, Abdullah Nasir, John M Doyle Trapped, ultracold molecules are a potentially powerful platform for probing physics beyond the Standard Model. YbOH, which has recently been laser cooled in one dimension to <600 μK, is predicted to have high sensitivity to the electron electric dipole moment. Here, we report on work aiming to laser cool and trap large numbers of YbOH molecules in three dimensions. We have constructed a He-3-based cryogenic beam source, achieving forward velocities of Yb and YbOH below 30 m/s, and a superconducting Zeeman-Sisyphus decelerator, designed to slow molecules to trappable velocities using three photon scatters. To increase the number of molecules that could be trapped, we use a laser-assisted chemical reaction between Yb and H2O to enhance molecular beam flux by more than an order of magnitude. We also present ultra-high-sensitivity measurements of vibrational branching ratios in YbOH, identifying vibrational states relevant for laser cooling using up to scattered 105 photons. From these measurements, we determine a feasible laser cooling scheme to achieve trapped samples of YbOH. |
Wednesday, June 2, 2021 11:42AM - 11:54AM Live |
K03.00007: Search for the atomic EDM of 171Yb in an optical dipole trap Tian Xia, Tao Zheng, Yang Yang, Shao-Zheng Wang, Zheng-Tian Lu, Jaideep T Singh, Zhuan-Xian Xiong We present a search for the atomic electric dipole moment (EDM) of 171Yb, a stable isotope with the ground state property of L = 0, S = 0, and I = 1/2. 171Yb atoms are captured by a two-stage MOT, transported using a movable optical dipole trap over 65 cm into a science chamber, and transferred to a static optical dipole trap. There, the atoms are allowed to precess under a uniform B field of 20 mG and a strong, reversible E field of 100 kV/cm. The precession frequencies measured under opposite E fields are used to search for the EDM. The preliminary result shows a sensitivity of E-26 e-cm in searching for 171Yb EDM. We describe the progress, challenges, and prospects of the experiment. Through this experiment, we develop atom manipulation techniques and study systematics for a parallel search for the EDM of 225Ra, a radioactive isotope expected to possess a much larger Schiff moment due to its nuclear octupole deformation. |
Wednesday, June 2, 2021 11:54AM - 12:06PM Live |
K03.00008: Quantum Non-Demolition Measurement on Spin Precession of Laser-Trapped 171Yb Atoms Yang Yang, Tao Zheng, Chang-Ling Zou, Tian Xia, Zheng-Tian Lu Quantum non-demolition (QND) measurement enhances the detection efficiency and measurement fidelity, and is highly desired for its applications in precision measurements and quantum information processing. We propose and demonstrate a QND scheme for the spin state of laser-trapped atoms, allowing the atoms in each spin state to be probed repeatedly. On 171Yb atoms held in an optical dipole trap, a spin-selective cycling transition is produced by introducing an ancillary laser. We measure the phase of spin precession of the 171Yb atoms in a 20-mG bias magnetic field. The QND approach reduces the measurement noise by ∼19 dB, to a level of 2.4 dB below the atom shot noise. |
Wednesday, June 2, 2021 12:06PM - 12:18PM Live |
K03.00009: Probing fundamental symmetries of deformed nuclei in polyatomic molecules Phelan Yu, Nicholas Hutzler Precision measurements of Schiff moments in heavy, deformed nuclei — such as radium-225 — are sensitive probes of beyond standard model T, P violation in the hadronic sector. While the most stringent limits on Schiff moments to date are set with diamagnetic atoms, polar polyatomic molecules can offer higher sensitivities with unique experimental advantages. Here, we report on recent theoretical progress [1] in identifying and characterizing new "designer" polyatomic ions for Schiff moment measurements (i.e. RaOH+, RaOCH3+), which promise to support extended trapping and interrogation times. Internally, these molecular species possess mechanical doublets of opposite parity with small splittings, leading to full polarization at low fields, internal comagnetometer states useful for rejection of systematic effects, and the ability to perform sensitive searches for T, P violation using a small number of trapped ions containing heavy exotic nuclei. |
Wednesday, June 2, 2021 12:18PM - 12:30PM Live |
K03.00010: Analytic Calculations of Time-Reversal Symmetry Violating Parameters Based on Relativistic Coupled-Cluster Analytic-Gradient Theory Chaoqun Zhang, Xuechen Zheng, Lan Cheng We report an analytic scheme for relativistic exact two-component coupled-cluster singles and doubles with a noniterative triples calculations of electric effective field, εeff, a time-reversal symmetry violating parameter that plays a key role in the interpretation of precision measurement of paramagnetic atoms and molecules for the search of electron electric dipole moment (eEDM). Benchmark calculations for the εeff values of twenty-one heavy-metal containing small molecules demonstrate the accuracy and efficacy of the present analytic scheme. The computational results show that metal methoxides including BaOCH3, YbOCH3, and RaOCH3 possess large |εeff| values similar to those of the corresponding fluorides and hydroxides, supporting the recent proposal of using the nearly degenerate rotational states of these symmetric-top molecules to enhance the sensitivity of eEDM measurements. Molecules containing late actinide elements, NoF, NoOH, LrO, and LrOH+ are shown to exhibit $εeff| values as large as around 200 GV/cm. The present analytic scheme provides an enhanced capability to calculate symmetry-violating parameters and enables fast and reliable screening of candidate molecules for the search of new physics. |
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