Bulletin of the American Physical Society
41st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 55, Number 5
Tuesday–Saturday, May 25–29, 2010; Houston, Texas
Session L4: Precision Measurements: EDMs and Other |
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Sponsoring Units: GPMFC Chair: Carol Tanner, University of Notre Dame Room: Regency Ballroom |
Thursday, May 27, 2010 2:00PM - 2:12PM |
L4.00001: Optical dipole trapping of radium atoms for EDM search W.L. Trimble, I.A. Sulai, R.H. Parker, K. Bailey, J.P. Greene, R.J. Holt, W. Korsch, Z.-T. Lu, P. Mueller, T.P. O'Connor, J. Singh We are developing an EDM search based on laser-cooled and trapped Ra-225 (half-life = 15 d) atoms. Due to octupole deformation of the nucleus, Ra-225 is predicted to be 2-3 orders of magnitude more sensitive to T-violating interactions than Hg-199, which currently sets the most stringent limits in the nuclear sector. Recently, we have succeeded in transferring Ra-226 atoms from a MOT into an optical dipole trap formed by a fiber laser beam at 1550 nm. For the EDM measurement, the cold atoms will be moved into the neighboring vacuum chamber inside magnetic shields where a pair of electrodes apply a 10 kV cm$^{-1}$electric field. This work is supported by DOE, Office of Nuclear Physics under contract No. DE-AC02-06CH11357. [Preview Abstract] |
Thursday, May 27, 2010 2:12PM - 2:24PM |
L4.00002: Hyperfine Zeeman structure of the PbF molecule and implications for an e-EDM measurement Priyanka Rupasinghe, Christopher McRaven, Tao Zheng Yang, Neil Shafer-Ray, Jens Grabow, Richard Mawhorter The Zeeman Effect on the ground state energy levels of the PbF molecule has been measured using kHz-resolution microwave spectroscopy at the University of Hannover. The data obtained has been used to to determine the magnetic G factors of the ground state. These G factors are important to our current efforts to measure the electron dipole moment of the electron (e-EDM.) Firstly, they provide a test of our theoretical understanding of the electronic structure of PbF as well as its sensitivity to CP violating physics. Secondly, quantitative understanding of the Zeeman Effect is critical for the detailed design of our experiment. In this talk we will present the results of our analysis, including an assessment of current theory and implications for future measurements. [Preview Abstract] |
Thursday, May 27, 2010 2:24PM - 2:36PM |
L4.00003: Progress towards measurement of the electron electric dipole moment using the $^{207}$Pb$^{19}$F molecule Christopher McRaven, Milinda Rupasinghe, Tao Zheng Yang, Poopalasingam Sivakumar, Neil Shafer-Ray The lead monofluoride molecule provides for a 1000- to 10,000- fold improvement in sensitivity to an electron electric dipole moment (e-EDM) over atomic-based measurements. In addition, unexpectedly closely spaced energy levels of opposite parity in the electronic ground state of $^{207}$Pb$^{19}$F along with its large dipole moment make this molecule an attractive candidate for improving the limit on the e-EDM. We present our progress towards a measurement of the e-EDM using $^{207}$Pb$^{19}$F, including a recently developed pseudo-continuous REMPI technique for detection from an effusive source. [Preview Abstract] |
Thursday, May 27, 2010 2:36PM - 2:48PM |
L4.00004: Search for the electric dipole moment of the electron with thorium monoxide Nicholas Hutzler, Wes Campbell, Yulia Gurevich, Paul Hess, Emil Kirilov, Maxwell Parsons, Elizabeth Petrik, Benjamin Spaun, Amar Vutha, David DeMille, Gerald Gabrielse, John Doyle The thorium monoxide molecule (ThO) in its metastable H state is a promising system for measuring or improving the limit on the permanent electric dipole moment of the electron (eEDM). We report on progress towards using ThO to measure the eEDM with a high-flux molecular beam. A cryogenic beam source has been constructed and is undergoing characterization and optimization. We also report on some preliminary realizations of state preparation and detection of laser-induced blue-shifted fluorescence from the EDM-sensitive H state. [Preview Abstract] |
Thursday, May 27, 2010 2:48PM - 3:00PM |
L4.00005: Characterization of a Continuous Supersonic Beam of Tungsten Atoms Jeongwon Lee, Jinhai Chen, Aaron Leanhardt Laser induced fluorescence spectroscopy is used to characterize the flux and velocity distribution of a continuous supersonic beam of ground state tungsten atoms. Tungsten atoms are seeded into a supersonic noble gas jet either by evaporation from a resistively heated filament or through sputtering from a dc electric discharge. This beam serves as the precursor to a continuous supersonic beam of ground state tungsten carbide molecules through the reaction $\textrm{W}+\textrm{CH}_4 \rightarrow \textrm{WC} + 2\textrm{H}_2$. Tungsten carbide (WC) has a $X^3\Delta_1$ ground state, which is ideal for a search for the permanent electric dipole moment (EDM) of the electron [1].\\[4pt] [1] J. Lee, E.R. Meyer, R. Paudel, J.L. Bohn, and A.E. Leanhardt, J. Mod. Opt. 56, 2005 (2009). [Preview Abstract] |
Thursday, May 27, 2010 3:00PM - 3:12PM |
L4.00006: Searching for Photon Rest Mass with Matterwave Interferometry Dallin S. Durfee, Christopher J. Erickson We discuss a proposed test of Coulomb's inverse-square law using matterwave interferometry. A deviation from the inverse-square law could be related to a possible non-zero rest mass of the photon, the exchange Boson for the electro-magnetic force. In the experiment, the wavefunction of ions will be split and recombined inside of a conducting shell. From the interferometer phase, it can be determined if fields in the shell change as the voltage applied to the shell is altered. If a changing field is detected, a violation of Coulomb's law is implied. In such an experiment, using reasonable experimental parameters, it could be possible to detect a photon rest mass as small as a several time $10^{-53}$ kg. [Preview Abstract] |
Thursday, May 27, 2010 3:12PM - 3:24PM |
L4.00007: Femtotesla atomic magnetometry in a microfabricated vapor cell W. Clark Griffith, Svenja Knappe, John Kitching Chip-scale atomic magnetometers developed at NIST are based around microfabricated vapor cells, consisting of an etched hole in a silicon wafer and anodically bonded pyrex windows. The vapor cells typically contain $^{87}$Rb atoms and several atmospheres of nitrogen buffer gas. Using a 3x2x1~mm vapor cell we have demonstrated a magnetometer with sensitivity better than 5 fT/Hz$^{1/2}$. The magnetometer is operated in the spin-exchange relaxation free (SERF) regime and uses two perpendicular light beams: a circularly polarized pump beam and an off-resonant linearly polarized probe beam. Magnetic fields are detected by analyzing the polarization direction of the probe beam. The measurement volume for this result is 1~mm$^3$, defined by the overlap of the pump and probe beams, giving a magnetic field energy resolution of $V B^2 / 2 \mu_0 = 95 \hbar$, within about a factor of two of the best result for an atomic magnetometer\footnote{H. B. Dang, A. C. Maloof, and M. V. Romalis, arXiv:0910.2206}. Achieving this sensitivity level in a millimeter scale vapor cell compared to larger cells requires special consideration of thermal magnetic noise due to the electrical conductivity of the silicon cell body and condensed alkali atoms on the cell walls. [Preview Abstract] |
Thursday, May 27, 2010 3:24PM - 3:36PM |
L4.00008: Effect of atomic electrons on 7.6 eV nuclear transition in $^{229}$Th$^{3+}$ Sergey Porsev, Victor Flambaum We have considered an effect of atomic electrons due to the electronic bridge process on the nuclear $^{229m}$Th -- $^{229g}$Th transition in $^{229}$Th$^{3+}$. Based on a recent experimental result we assumed the energy difference between the isomeric and the ground nuclear states to be equal to 7.6 eV. We have calculated the ratios of the electronic bridge process probability ($\Gamma_{\rm EB}$) to the probability of the nuclear radiative transition ($\Gamma_N$) for the electronic $5f_{5/2} \rightarrow 6d_{3/2},6d_{5/2},7s$ and the $7s \rightarrow 7p_{1/2},7p_{3/2}$ transitions and found $\Gamma_{\rm EB}/\Gamma_N \sim 0.01\div0.1$ for the former and $\Gamma_{\rm EB}/\Gamma_N \sim 20$ for the latter. [Preview Abstract] |
Thursday, May 27, 2010 3:36PM - 3:48PM |
L4.00009: Probing Long-Range Configurations of Molecular Hydrogen Near the Third Dissociation Energy Elizabeth McCormack Double resonance spectroscopy via the$EF{ }^1\Sigma _g^+ ,v'_{EF} =6,J'$ state has been used to probe the H(n=1) + H(n=3) dissociation threshold region with quantum state selectivity and high energy resolution. Above threshold the continuum is detected by ionizing H(n=3) to produce H$^{+}$, which is then detected by using a time-of-flight mass spectrometer. The ion yield above threshold has several features. Broad structures due to an extension of the series of vibrational levels belonging to the inner and outer wells of the \textit{ungerade} double-well $B"\overline B $(3)${ }^1\Sigma _u^+ $state into the continuum are observed. Also present are sharp features due to vibrationally excited Rydberg states of H$_{2}$. Several unassigned features may be explained by transitions to extremely long-range rovibrational levels of the 6th member of the ${ }^1\Sigma _u^+ $ series of states in H$_{2}$. The new measurements are in good agreement with the energies predicted by \textit{ab initio} calculations of nonadiabatic couplings between the ${ }^1\Sigma _u^+ $ and ${ }^1\Pi _u^+$ series of states of this fundamental system. [Preview Abstract] |
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