Bulletin of the American Physical Society
48th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 62, Number 8
Monday–Friday, June 5–9, 2017; Sacramento, California
Session M7: Precise Tests of Fundamental Symmetries |
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Chair: Eric Norrgard, Yale University Room: 313 |
Thursday, June 8, 2017 8:00AM - 8:12AM |
M7.00001: A precision measurement of the electron’s electric dipole moment using trapped molecular ions William B. Cairncross, Daniel N. Gresh, Matt Grau, Kevin C. Cossel, Yiqi Ni, Tanya Roussy, Yuval Shagam, Jun Ye, Eric A. Cornell A search for a permanent electric dipole moment of the electron (eEDM) constitutes an essentially background-free test for physics beyond the Standard Model. While some extensions to the Standard Model suggest an eEDM at presently achievable levels of sensitivity, none has yet been detected [1]. Independent measurements using different experimental techniques provide essential confirmation of this result and potential for sensitivity improvements. We will report on the first precision measurement of the eEDM using trapped molecular ions, demonstrating a uniquely long coherence time that provides excellent rejection of systematic errors and high eEDM sensitivity. \\[4pt] [1] J.~Baron, W.~C.~Campbell, D.~DeMille, J.~M.~Doyle, G.~Gabrielse, Y.~V.~Gurevich, P.~W.~Hess, N.~R.~Hutzler, E.~Kirilov, I.~Kozyryev, B.~R.~O'Leary, C.~D.~Panda, M.~F.~Parsons, B.~Spaun, A.~C.~Vutha, and A.~D.~West, Science \textbf{343}, 269 (2014) [Preview Abstract] |
Thursday, June 8, 2017 8:12AM - 8:24AM |
M7.00002: Abstract Withdrawn
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Thursday, June 8, 2017 8:24AM - 8:36AM |
M7.00003: Improved Thermochemical Beam Source of ThO for Measuring the Electric Dipole Moment of the Electron Elizabeth West, Jacob Baron, Nicholas Hutzler, Daniel Ang, Jonathan Haefner, Zack Lasner, Cristian Panda, Adam West, David DeMille, Gerald Gabrielse, John Doyle We report new results on a cryogenic buffer gas beam source of the reactive diatomic species thorium monoxide (ThO) for the ACME collaboration's measurement of the electric dipole moment of the electron (eEDM). The beam source is based on a high-temperature chemical reaction between thorium metal and thorium dioxide that produces ThO in the gas phase at a favorable rate. This source has been demonstrated to produce long, $\approx 80$ ms pulses of ThO with a time-averaged flux 10 times larger than the previous ablation-based beam source [1]. Other beam properties, such as forward velocity, rotational temperature, and divergence have been measured and shown to be comparable to or only marginally less favorable than those of the ablation source. By enhancing the experiment's achievable count rate, this thermochemical beam source could improve the statistical sensitivity of a future iteration of the ACME collaboration's eEDM measurement by a factor of three. [1] N.~Hutzler et al., \emph{PCCP} \textbf{13}, (2011) 18976--18985. [Preview Abstract] |
Thursday, June 8, 2017 8:36AM - 8:48AM |
M7.00004: Progress towards a second-generation eEDM measurement using trapped molecular ions Daniel Gresh, William Cairncross, Tanya Roussy, Yuval Shagam, Yan Zhou, Kia Boon Ng, Fatemeh Abbasi Razgaleh, Parker Hinton, Jun Ye, Eric Cornell Our current uncertainty budget in the first-generation measurement of the electron's electric dipole moment (eEDM) is dominated by statistical uncertainty [1]. Our second-generation apparatus will leverage larger ion number, longer measurement coherence times, and increased quantum efficiencies to gain an order of magnitude improvement in statistical sensitivity. The second-generation experiment consists of 1) a larger ion trapping volume, increasing the number of ions available to contribute to the eEDM signal; 2) improved uniformity of trapping and rotating bias electric fields, leading to a colder ion cloud and to fewer decohering ion-ion collisions; and 3) a larger rotating bias electric field, resulting in a direct increase in measurement coherence time. We will present progress on the new system and on the expected increase in statistical sensitivity.\\ \\[4pt] [1] W. B. Cairncross \textit{et al.}, in preparation. [Preview Abstract] |
Thursday, June 8, 2017 8:48AM - 9:00AM |
M7.00005: The Electric Dipole Moment of Radium Matthew Dietrich, Michael Bishof, Kevin Bailey, John Greene, Roy Holt, Wolfgang Korsch, Zheng-Tian Lu, Peter Mueller, Thomas O'Connor, Tenzin Rabga, Roy Ready, Jaideep Singh Due to its large nuclear octupole deformation and high atomic mass, the radioactive Ra-225 isotope is a favorable case for an electric dipole moment (EDM); it is particularly sensitive to CP-violating interactions in the nuclear medium. We have developed a cold-atom approach of measuring the atomic EDM of Ra-225 atoms held stationary in an optical dipole trap. We previously demonstrated this technique with an initial experimental upper limit of \textbar d(225Ra)\textbar \textless 5e-22 e-cm (95{\%} C.L.), and have since improved this limit 36-fold to 1.4e-23 e-cm. This is not only the first time laser-cooled atoms have been used to measure an EDM, but also the first time the EDM of any octupole deformed species has been measured. Upcoming improvements are expected to dramatically improve our sensitivity, and significantly improve on the search for new physics in several sectors. This work is supported by U.S. DOE, Office of Science, Office of Nuclear Physics, under contract DE-AC02-06CH11357. [Preview Abstract] |
Thursday, June 8, 2017 9:00AM - 9:12AM |
M7.00006: The ALPHA Experiment: Testing CPT and Gravity with Trapped Antihydrogen Makoto Fujiwara Over the past decade, the ALPHA (Antihydrogen Laser Physics Apparatus) Collaboration at CERN has been working towards precision tests of fundamental symmetries between matter and antimatter [1-4]. Recently, we have succeeded in observing, for the first time, the 1s-2s transition in trapped antihydrogen [5]. The initial measurement had a sensitivity of 2x10$^{-10}$, and we expect a significant improvement in the near future. In the meantime, we are constructing a new apparatus, ALPHA-g, in order to measure the gravitational force on antimatter by dropping antihydrogen atoms. In this talk, I will give an overview and prospects of the ALPHA experiment. REFERENCES: [1] Andresen, G. B. et al. Trapped antihydrogen, {¥it Nature} 468, 673–676 (2010). [2] Andresen, G. B. et al. Confinement of antihydrogen for 1,000 seconds, Nature Physics 7, 558–564 (2011). [3] Amole, C. et al. Resonant quantum transitions in trapped antihydrogen atoms, Nature 483, 439–443 (2012). [4] Ahmadi, M. et al. An improved limit on the charge of antihydrogen from stochastic acceleration, Nature 529, 373–376 (2016). [5] Ahmadi, M. et al., Observation of the 1S-2S transition in trapped antihydrogen, Nature 541, 506-510 (2017). [Preview Abstract] |
Thursday, June 8, 2017 9:12AM - 9:24AM |
M7.00007: Prospects for testing CPT and Lorentz symmetry with electronic transitions Arnaldo Vargas, V. Alan Kosteleck\'y Empirical evidence for minuscule deviations from the principle of relativity could help physicists develop a theory that accurately describes gravity at the quantum scale. Measurements of electronic transitions are among the most precise and accurate measurements in all science, and they offer a sensible approach to the search for Lorentz and CPT violation. Using the Standard-Model Extension, phenomenological models for Lorentz violation in commonly measured atomic transitions are obtained. This includes models for experiments with ordinary matter, muonic atoms, and antimatter. Clock-comparison experiments are also considered, including experiments with microwave and optical atomic clocks. In all cases, potential signals for Lorentz and CPT violation are singled out and estimates of the sensitivity of the experiments are discussed. [Preview Abstract] |
Thursday, June 8, 2017 9:24AM - 9:36AM |
M7.00008: Testing Lorentz and CPT invariances in quantum electrodynamics with Penning traps Yunhua Ding, V. Alan Kosteleck\'y The Lorentz and CPT invariances of relativity are fundamental in physics. However, tiny violations of these invariances could emerge in an underlying unified theory such as strings. This talk explores Lorentz- and CPT-violating quantum electrodynamics, presenting the general Lagrange density for Lorentz violation with operators of mass dimension up to six and analyzing results from precision experiments on particles and antiparticles confined to a Penning trap. Observable signals are discussed, and new bounds for Lorentz-violating coefficients are extracted. [Preview Abstract] |
Thursday, June 8, 2017 9:36AM - 9:48AM |
M7.00009: The ALPHATRAP $\textit{g}$-Factor Experiment Ioanna Arapoglou, Alexander Egl, Martin Hocker, Sandro Kraemer, Tim Sailer, Andreas Weigel, J. R. Crespo Lopez-Urrutia, Robert Wolf, Sven Sturm, Klaus Blaum ALPHATRAP is a high-precision Penning-trap experiment that aims for the most stringent test of bound-state quantum electrodynamics (BS-QED) in the strong field regime. These fields are provided by heavy highly-charged ions (HCI), such as hydrogen-like $^{208}\mathrm{Pb}^{81+}$, where the electron is exposed to the strong binding potential of the nucleus. The storage and manipulation of the ions is achieved using a double Penning-trap system in which the electron's $g$-factor is deduced from measuring its magnetic moment. The setup includes several ion creation possibilities for offline ion production, additional to the online injection of heavy HCI from the Heidelberg Electron Beam Ion Trap. This will deliver the heavy HCI via an ion beam-line, to the cryogenic double Penning-trap system. The latter consists of the so called Precision Trap for high-precision measurements of the ion cyclotron frequency in a homogeneous magnetic field, and the Analysis Trap for spin state detection of the bound electron in a magnetic bottle configuration. This experimental setup not only enables high-precision tests of BS-QED, but also allows the determination of fundamental constants, such as the fine structure constant $\alpha$ and the atomic mass of the electron $m_e$, to competitive precision. [Preview Abstract] |
Thursday, June 8, 2017 9:48AM - 10:00AM |
M7.00010: High-precision calculation of La$^-$ atomic properties for anion laser cooling Marianna Safronova, Ulyana Safronova, Sergey Porsev Anion laser cooling holds the potential to allow the production of ultracold ensembles of any negatively charged species. The negative ion of lanthanum, La$^-$, was proposed as the best candidate for laser cooling of any atomic anion [1]. A very exciting application of La$^-$ laser cooling includes cooling of antiprotons for antihydrogen formation and subsequent tests of CPT invariance and weak equivalence principle [2]. A calculation of anion properties is a very difficult task, with complicated electronic structure of lanthanides presenting additional major problems. In this work, we present novel theoretical treatment of La$^-$. Affinity, energy levels, E1 matrix elements, transition rates, branching ratios, lifetimes, and hyperfine constants are calculated using high-precision CI+all-order method. Calculated theoretical transition energies are in agreement with measured values to 0.2\% - 2\%, signifying drastic improvement of theoretical accuracy for negative ions. Recommended values of transition rates and branching ratios of importance to the realization of laser cooling with of La$^-$ are presented and critically evaluated for their accuracy. [1] S. M. O'Malley and D. R. Beck, PRA 81, 032503 (2010). [2] A. Kellerbauer and J. Walz, N. J. Phys. 8, 45 (2006). [Preview Abstract] |
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