Experimental perspectives on the matter-antimatter asymmetry puzzle: developments in electron EDM and antihydrogen experiments

In the search for clues to the matter-antimatter puzzle, experiments with atoms or molecules play a particular role. These systems allow measurements with very high precision, as demonstrated by the unprecedented limits down to $10^{-30}$ e.cm on electron EDM using molecular ions, and relative measurements at the level of $10^{-12}$ in spectroscopy of antihydrogen atoms. Building on these impressive measurements, new experimental directions offer potentials for drastic improvements. We review here some of the new perspectives in those fields and their associated prospects for new physics searches

Direct Observation of the Spontaneous Emission of the Hyperfine Transition F = 4 to F = 3 in Ground State Hydrogenlike 165Ho66+ in an Electron Beam Ion Trap

We report the first direct laboratory measurement of the spontaneous emission due to the hyperfine splitting of the ground state of a highly charged hydrogenlike ion excited by electron collisions. The transition between the F = 4 and F = 3 levels of the 1s2S1/2 configuration of hydrogenlike 165Ho65+ was observed and its wavelength was determined to 5726.4±1.5Å. After taking into account relativistic, nuclear charge distribution, Bohr-Weisskopf, and QED corrections, we observe a significant deviation from commonly tabulated values of the nuclear dipole magnetic moment of this nucleu

Precision measurement of the lifetime of the 1s2s3S1 metastable level in heliumlike O6+

The lifetime of the 1s2s3S1 level of the He-like O6+ ion has been measured using the Electron Beam Ion Trap in the magnetic trapping mode. A value of 956-4+5 μs is found, which corresponds to a radiative transition rate of 1046-5+4 s-1 for the magnetic dipole transition to the 1s21S0 ground state. This value is in excellent agreement with recent theoretical predictions and distinguishes among different treatments of negative energy states and correlation in multiconfiguration Dirac-Fock calculations

A high-resolution transmission-type x-ray spectrometer designed for observation of the Kα transitions of highly charged high-Z ions

High-resolution reflection-type crystal spectrometers have been used for x-ray energies up to 13 keV, e.g., the K-shell radiation of heliumlike Kr. In order to extend crystal spectrometer measurements to higher energy x rays from higher-Z elements, we employ the crystal in transmission. The geometry we use is known as DuMond geometry. Using such a transmission-type crystal x-ray spectrometer, we have measured the K-shell radiation of various highly charged high-Z ions. In particular, we present a measurement of the 1s2p 1P1→1s2 1S0 transition in heliumlike xenon, Xe52+. For this transition, we measure a linewidth of 34 eV, which demonstrates that the resolving power we achieved with the new spectrometer is on the order of 100

Radio frequency reflectometry and charge sensing of a precision placed donor in silicon

We compare charge transitions on a deterministic single P donor in silicon using radio frequency reflectometry measurements with a tunnel coupled reservoir and DC charge sensing using a capacitively coupled single electron transistor (SET). By measuring the conductance through the SET and comparing this with the phase shift of the reflected RF excitation from the reservoir, we can discriminate between charge transfer within the SET channel and tunneling between the donor and reservoir. The RF measurement allows observation of donor electron transitions at every charge degeneracy point in contrast to the SET conductance signal where charge transitions are only observed at triple points. The tunnel coupled reservoir has the advantage of a large effective lever arm (~35%) allowing us to independently extract a neutral donor charging energy ~62 +/- 17meV. These results demonstrate that we can replace three terminal transistors by a single terminal dispersive reservoir, promising for high bandwidth scalable donor control and readout.Comment: 5 pages, 3 figures. Copyright (2015) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physic

Laboratory Measurements of Fe XXIV L-Shell Line Emission

Recent ASCA spectra exhibit discrepancies with the relative line intensities of various Fe XXIII and XXIV L-shell emission lines predicted by standard plasma emission codes. To address this issue, we have carried out a series of high-resolution, broadband measurements of Fe XXIV line emission using an electron beam ion trap facility. X-ray lines produced in the trap are detected and resolved using Bragg crystal spectrometers. We report measurements of 33 2 and 43 2 transitions, which result primarily from electron impact excitation. Overall, good agreement is found with distorted wave calculations

Laboratory Measurements of Fe XXIV L-Shell Line Emission

Recent ASCA spectra exhibit discrepancies with the relative line intensities of various Fe XXIII and XXIV L-shell emission lines predicted by standard plasma emission codes. To address this issue, we have carried out a series of high-resolution, broadband measurements of Fe XXIV line emission using an electron beam ion trap facility. X-ray lines produced in the trap are detected and resolved using Bragg crystal spectrometers. We report measurements of 3 → 2 and 4 → 2 transitions, which result primarily from electron impact excitation. Overall, good agreement is found with distorted wave calculations

Measurement and interpretation of the polarization of the x-ray line emission of heliumlike Fe XXV excited by an electron beam

The linear polarization of the 1s2p 1P1→1s2 1S0 resonance line, the 1s2p 3P1,2→1s2 1S0 intercombination lines, and the 1s2s 3S1→1s2 1S0 forbidden line was measured in heliumlike Fe XXV excited near threshold by a monoenergetic electron beam. The measurement was carried out with a high-resolution x-ray spectrometer employing a set of two analyzing crystals that acted as polarizers by selectively reflecting the individual polarization components. A value of +0.56-0.08+0.17 was determined for the polarization of the 1P1 line, -0.53-0.02+0.05 for the 3P2 line, -0.22-0.02+0.05 for the 3P1 line, and -0.076-0.007+0.007 for the 3S1 line. The measurements were compared with results from a relativistic distorted-wave calculation, which was carried out for a number of mid-Z heliumlike ions (Mg10+–Kr34+), and good agreement was found. By contrast, disagreement was noted with predictions based on Coulomb-Born calculations, allowing us to distinguish between theoretical approaches

Microwave spectroscopic study of the hyperfine structure of antiprotonic helium-3

In this work we describe the latest results for the measurements of the hyperfine structure of antiprotonic helium-3. Two out of four measurable super-super-hyperfine SSHF transition lines of the (n,L)=(36,34) state of antiprotonic helium-3 were observed. The measured frequencies of the individual transitions are 11.12548(08) GHz and 11.15793(13) GHz, with an increased precision of about 43% and 25% respectively compared to our first measurements with antiprotonic helium-3 [S. Friedreich et al., Phys. Lett. B 700 (2011) 1--6]. They are less than 0.5 MHz higher with respect to the most recent theoretical values, still within their estimated errors. Although the experimental uncertainty for the difference of 0.03245(15) GHz between these frequencies is large as compared to that of theory, its measured value also agrees with theoretical calculations. The rates for collisions between antiprotonic helium and helium atoms have been assessed through comparison with simulations, resulting in an elastic collision rate of gamma_e = 3.41 +- 0.62 MHz and an inelastic collision rate of gamma_i = 0.51 +- 0.07 MHz.Comment: 15 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:1102.528