Electric Dipole Moments: A Global Analysis

We perform a global analysis of searches for the permanent electric dipole moments (EDMs) of the neutron, neutral atoms, and molecules in terms of six leptonic, semileptonic, and nonleptonic interactions involving photons, electrons, pions, and nucleons. Translating the results into fundamental CP-violating effective interactions through dimension six involving Standard Model particles, we obtain rough lower bounds on the scale of beyond the Standard Model CP-violating interactions ranging from 1.5 TeV for the electron EDM to 1300 TeV for the nuclear spin-independent electron-quark interaction. We show that future measurements involving systems or combinations of systems with complementary sensitivities to the low-energy parameters may extend the mass reach by an order of magnitude or more.Comment: 15 pages, 1 figur

Neutron-decay Correlation Measurements with Polarized and Pulsed Beams

AbstractNeutron-decay polarization correlations arise due to the interference of amplitudes with different transformation properties, i.e. V, A, S, P, and T corresponding to vector, axial vector, scalar, pseudoscalar and tensor. Measurements of a number of these correlations are used to constrain fundamental parameters of the Standard Model as well as probe new physics. Recent and future efforts that I will discuss include time-reversal violating correlations, e.g. the D coefficient and its relation to the neutron EDM as well as the beta-neutrino correlation, with emphasis on systematic errors that could arise from residual polarization that can be measured with a pulsed neutron beam such as provided by the SNS or ESS

Operation of a single mode external-cavity laser diode array near 780 nm

We have narrowed the spectral bandwidth of a commercial 2 W laser diode array to be less than 120 MHz near 780 nm. The external-cavity laser diode array system is a standard double-pass Littman–Metcalf configuration operating on a dominant single longitudinal mode. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69845/2/RSINAK-73-12-4169-1.pd

The search for a permanent electric dipole moment using 129Xe and 3He

Time reversal and parity non‐invariant interactions within an atom naturally give rise to an atomic permanent electric dipole moment (PEDM). For noble gas atoms, the size of such a PEDM scales as Z2 and higher powers of Z depending on the actual manifestation of T non‐invariance, most importantly a distribution of electric dipole moment within the nucleus (Schiff Moment) and a T‐odd tensor interaction between the nucleus and atomic electrons. We have developed techniques to simultaneously measure the PEDMs of 129Xe and 3He in a single cell in order to mitigate systematic effects due to leakage currents and common mode problems such as magnetic field and time base noise. The philosophy of our approach is that PEDM of 3He is negligible compared to that of 129Xe and thus we use the 3He as a ‘‘magnetometer’’ and monitor of systematic effects. Sensitivity of ≊10−25 e‐cm per day has been demonstrated in preliminary work using a free‐induction decay technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87703/2/73_1.pd

The search for a permanent electric dipole moment using 129Xe and 3He

Time reversal and parity non‐invariant interactions within an atom naturally give rise to an atomic permanent electric dipole moment (PEDM). For noble gas atoms, the size of such a PEDM scales as Z2 and higher powers of Z depending on the actual manifestation of T non‐invariance, most importantly a distribution of electric dipole moment within the nucleus (Schiff Moment) and a T‐odd tensor interaction between the nucleus and atomic electrons. We have developed techniques to simultaneously measure the PEDMs of 129Xe and 3He in a single cell in order to mitigate systematic effects due to leakage currents and common mode problems such as magnetic field and time base noise. The philosophy of our approach is that the PEDM of 3He is negligible compared to that of 129Xe and thus we use the 3He as a ‘‘magnetometer’’ and monitor of systematic effects. Sensitivity of ≊10−25 e‐cm per day has been demonstrated in preliminary work using a free induction decay technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87730/2/84_1.pd

Frequency shifts in noble-gas magnetometers

Polarized nuclei are a powerful tool in nuclear spin studies and in searches for beyond-the-standard model physics. Noble-gas comagnetometer systems, which compare two nuclear species, have thus far been limited by anomalous frequency variations of unknown origin. We studied the self-interactions in a $^3$He-$^{129}$Xe system by independently addressing, controlling and measuring the influence of each component of the nuclear spin polarization. Our results directly rule out prior explanations of the shifts, and demonstrate experimentally that they can be explained by species dependent self-interactions. We also report the first gas phase frequency shift induced by $^{129}$Xe on $^3$He.Comment: v.

Polarized 129Xe129Xe optical pumping/spin exchange and delivery system for magnetic resonance spectroscopy and imaging studies

We describe the design and construction of a laser-polarized 129Xe129Xe production and delivery system that is used in our in vitro and in vivo magnetic resonance imaging (MRI) experiments. The entire apparatus including lasers and optics, rapidly actuated valves, heating and cooling, and transport tubing lies in the high magnetic field environment of a 2 T MRI magnet. With approximately 7.5% 129Xe129Xe polarization, 157 cc atm of xenon gas is produced and stored as xenon ice every 5 min. Large quantities of polarized 129Xe129Xe can be obtained by cycling this process. The xenon is subsequently delivered in a controlled fashion to a sample or subject. With this device we have established the feasibility of using laser-polarized 129Xe129Xe as a magnetic tracer in MRI. This reliable, effective, and relatively simple production method for large volumes of 129Xe129Xe can be applied to other areas of research involving the use of laser-polarized noble gases. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69879/2/RSINAK-70-2-1546-1.pd

Magnetic Resonance Imaging with laser polarized 129Xe129Xe

Magnetic Resonance Imaging with laser-polarized 129Xe129Xe can be utilized to trace blood flow and perfusion in tissue for a variety of biomedical applications. Polarized xenon gas introduced in to the lungs dissolves in the blood and is transported to organs such as the brain where it accumulates in the tissue. Spectroscopic studies combined with imaging have been used to produce brain images of 129Xe129Xe in the rat head. This work establishes that nuclear polarization produced in the gas phases survives transport to the brain where it may be imaged. Increases in polarization and delivered volume of 129Xe129Xe will allow clinical measurements of regional blood flow. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87439/2/200_1.pd

Polarization and relaxation of radon

Investigations of the polarization and relaxation of $^{209}$Rn by spin exchange with laser optically pumped rubidium are reported. On the order of one million atoms per shot were collected in coated and uncoated glass cells. Gamma-ray anisotropies were measured as a signal of the alignment (second order moment of the polarization) resulting from the combination of polarization and quadrupole relaxation at the cell walls. The temperature dependence over the range 130$^\circ$C to 220$^\circ$C shows the anisotropies increasing with increasing temperature as the ratio of the spin exchange polarization rate to the wall relaxation rate increases faster than the rubidium polarization decreases. Polarization relaxation rates for coated and uncoated cells are presented. In addition, improved limits on the multipole mixing ratios of some of the main gamma-ray transitions have been extracted. These results are promising for electric dipole moment measurements of octupole-deformed $^{223}$Rn and other isotopes, provided sufficient quantities of the rare isotopes can be produced.Comment: 4 pages, 4 figure