Bulletin of the American Physical Society
50th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 64, Number 4
Monday–Friday, May 27–31, 2019; Milwaukee, Wisconsin
Session C02: Tests of Discrete Symmetries |
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Sponsoring Units: GPMFC Chair: Alex Sushkov, Boston University Room: Wisconsin Center 101AB |
Tuesday, May 28, 2019 10:30AM - 11:00AM |
C02.00001: Testing the Standard Model with Electron Dipole Moments Invited Speaker: Gerald Gabrielse Our new ACME measurement of the electron electric dipole moment* has a sensitivity greater than past measurements by a factor of 12. The result is consistent with the standard model prediction rather than supersymmetric models, for example. Meanwhile, our measurement of the electron magnetic dipole moment** agrees with the standard model’s most precise prediction to a part in 10$^{12}$ , though there is now a 2.4 standard deviation separation of measurement and prediction. A new measurement has been started.\\ \\ * ACME Collaboration, Nature 562, 355 (2018)\\ \\ ** D. Hanneke, S. Fogwell Hoogerheide and G. Gabrielse, Phys. Rev. A, 83 052122 (2011) [Preview Abstract] |
Tuesday, May 28, 2019 11:00AM - 11:30AM |
C02.00002: Searching for light scalar dark matter in the acoustic and radio-frequency range with atomic spectroscopy Invited Speaker: Dionysios Antypas The fundamental constants of nature are invariant in time within the standard model of particle physics, but become dynamical in a number of theories beyond the standard model. The notion that these constants oscillate rapidly has recently received attention, as such oscillations can arise in models that explain the origin of the dark matter relic abundance, assuming it is of the form of a light scalar. The relaxion, a particle introduced to provide a cosmological solution to the hierarchy problem, was shown within minimal models to be a viable light dark matter candidate. Furthermore, such particles might form boson stars, thereby increasing dark matter density locally and enhancing the potential observability of this scenario. I will report on the results of a recent experiment that employs spectroscopy in atomic cesium to probe fast oscillations of the fine structure constant and the electron mass, in the acoustic to and radio frequency range. Our measurements provide constraints on couplings of the dark matter field to standard-model matter, which within relaxion star scenarios, compete with constraints coming from equivalence principle and fifth force experiments. [Preview Abstract] |
Tuesday, May 28, 2019 11:30AM - 11:42AM |
C02.00003: The Upcoming JILA Gen. III eEDM Experiment Kia Boon Ng, Yan Zhou, William Cairncross, Tanya Roussy, Tanner Grogan, Yuval Shagam, Kevin Boyce, Antonio Vigil, Madeline Pettine, Jun Ye, Eric Cornell ThF$^+$ is the champion for the third-generation (Gen. III) measurement of the electric dipole moment of the electron (eEDM) at JILA. Compared to the current HfF$^+$ eEDM experiment, ThF$^+$ has several advantages: (i) the eEDM-sensitive state ($^3\Delta_1$) is the ground state [1,2], with a projected coherence time on the order of a few minutes; and (ii) its effective electric field (38 GV/cm) is 50\% larger than that of HfF$^+$ [3], which promises a direct increase of the eEDM sensitivity. Herein, we present the final spectroscopic work on the $^3\Delta_1$ state, and discuss multiplexing strategies to increase our effective count rate in Gen. III by two orders of magnitude over the Gen. II experiment.\\ \\ 1. Gresh, Daniel N., et al. ``Broadband velocity modulation spectroscopy of ThF+ for use in a measurement of the electron electric dipole moment.'' Journal of Molecular Spectroscopy 319 (2016): 1-9.\\ 2. Zhou, Yan, et al. ``Visible and ultraviolet laser spectroscopy of ThF.'' arXiv:1901.06084 (2019)\\ 3. Skripnikov, L. V., and A. V. Titov. ``Theoretical study of ThF+ in the search for T, P-violation effects: Effective state of a Th atom in ThF+ and ThO compounds.'' Physical Review A 91.4 (2015): 042504. [Preview Abstract] |
Tuesday, May 28, 2019 11:42AM - 11:54AM |
C02.00004: Interpreting the Electron EDM Constraint Qianshu Lu, Cari Cesarotti, Yuichiro Nakai, Aditya Parikh, Matthew Reece The ACME collaboration has recently announced a new constraint on the electron EDM, $|d_e| < 1.1 \times 10^{-29}\, e\, {\rm cm}$. This is a powerful constraint on CP-violating new physics: even new physics generating the EDM at two loops is constrained at the multi-TeV scale. I will interpret the electron EDM bound through first a general order-of-magnitude analysis, then discussions of two specific scenarios: one is SUSY, where new physics involves the electroweak sector and couples to the Higgs. The other is the "QULE operators", $(q_f \bar{\sigma}^{\mu \nu}{\bar u}_f) \cdot (\ell {\bar{\sigma}}_{\mu \nu} {\bar e})$, where new physics couples to the charm or top quark. The electron EDM bound is the leading constraint on a wide variety of theories of CP-violating new physics. I will also briefly discuss the implications of future improvements in EDM searches. [Preview Abstract] |
Tuesday, May 28, 2019 11:54AM - 12:06PM |
C02.00005: Precision spectroscopy of the 1S-2S transition in antihydrogen Graham Stutter Recent years have seen rapid progress in the field of antimatter research. One of the major milestones passed during this period was the observation and characterization of the 1S--2S transition in trapped antihydrogen by the ALPHA experiment at CERN[1,2]. Doppler-free laser spectroscopy of the corresponding transition in hydrogen has been performed to a precision of 4.2 parts in $10^{15}$[3], which makes it an extremely promising candidate for stringent tests of charge-parity-time (CPT) symmetry[4]. We present a description of the ALPHA experimental apparatus and our latest spectroscopy results, as well as prospects for achieving hydrogen-like precision in our apparatus.\newline\newline [1] Nature \textbf{541}, 506--510 (2017)\newline [2] Nature \textbf{557}, 71--75 (2018)\newline [3] Phys.\ Rev.\ Lett., \textbf{107}, 203001 (2011)\newline [4] Phys.\ Rev.\ D \textbf{92}, 056002 (2015) [Preview Abstract] |
Tuesday, May 28, 2019 12:06PM - 12:18PM |
C02.00006: Upgrades for an Improved Measurement of the Permanent EDM of Ra-225 Tenzin Rabga, Kevin Bailey, Michael Bishof, Donald Booth, Matthew Dietrich, John Greene, Peter Mueller, Thomas O'Connor, Zheng-Tian Lu, Roy Ready, Jaideep Singh, Tian Xia A non-zero Electric Dipole Moment (EDM) in a non-degenerate system violates time-reversal (T) symmetry and consequently also charge-parity (CP) symmetry. ~EDM measurements are therefore sensitive searches for new CP violating interactions. The octupole deformation and nearly degenerate nuclear parity doublet in Ra-225 make it an attractive candidate for probing CP violations in the hadronic sector. Further experimental upgrades are being implemented to enhance the current EDM sensitivity for Ra-225. These include more than a factor of three enhancement in the electric field from our electrode upgrade and a STIRAP-based electron shelving for improved state detection efficiency. With these upgrades in place our EDM sensitivity should increase by about two orders of magnitude and allow us to substantially improve constraints on certain T-violating processes within the nucleus. Updates on the status of these upgrades will be provided. This work is supported by the U.S. DOE, Office of Science, Office of Nuclear Physics, under contract DE-AC02-06CH11357 and the Michigan State University. [Preview Abstract] |
Tuesday, May 28, 2019 12:18PM - 12:30PM |
C02.00007: Search for Parity- and Time Reversal-Violating Nuclear Spin-Dependent Interactions in $^{\mathrm{205}}$TlF Olivier Grasdijk, David DeMille, Jakob Kastelic, David Kawall, Steve Lamoreaux, Oskari Timgren, Konrad Wenz, Tristan Winick, Trevor Wright, Tanya Zelevinsky Parity (P)- and time reversal (T)-violating interactions are sensitive probes of physics beyond the Standard Model. CeNTREX (Cold molecule Nuclear Time-Reversal Experiment) aims to search for nuclear spin-dependent P- and T-violating interactions, e.g. due to the nuclear Schiff Moment of $^{\mathrm{205}}$Tl, in the molecule thallium fluoride (TlF). We will look for a P-,T-violating interaction by sending a cryogenic molecular beam of TlF through an interaction region where the direction of an electric field, relative to the molecular rotational angular momentum, is alternately switched. This will generate a change in the nuclear spin precession frequency proportional to the Schiff moment. We project a significant improvement in sensitivity compared to the current state of the art. Instrumental in achieving this sensitivity is the use of optical cycling for efficient detection, rotational cooling, an electrostatic molecular lens, and a 3 meter long interaction region. We describe the recent progress and current status of the CeNTREX experiment. [Preview Abstract] |
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