Search

Background: Lorentz invariance is key in our understanding of nature, yet relatively few experiments have tested Lorentz invariance in weak interactions.Purpose: Our goal is to obtain limits on Lorentz-invariance violation in weak interactions, in particular rotational invariance in beta decay.Method: We search for a dependence of the lifetime of Na-20 nuclei on the nuclear spin direction. Such directional dependence would be evidence for Lorentz-invariance violation in weak interactions. A difference in lifetime between nuclei that are polarized in the east and west direction is searched for. This difference is maximally sensitive to the rotation of the Earth, while the sidereal dependence is free from most systematic errors.Results: The experiment sets a limit of 2 x 10(-4) at 90% C.L. on the amplitude of the sidereal variation of the relative lifetime differences, an improvement by a factor 15 compared to an earlier result.Conclusions: No significant violation of Lorentz invariance is found. The result sets limits on parameters of theories describing Lorentz-invariance violation.

Background: Lorentz invariance is key in our understanding of nature, yet relatively few experiments have tested Lorentz invariance in weak interactions. Purpose: Our goal is to obtain limits on Lorentz-invariance violation in weak interactions, in particular rotational invariance in beta decay. Method: We search for a dependence of the lifetime of Na-20 nuclei on the nuclear spin direction. Such directional dependence would be evidence for Lorentz-invariance violation in weak interactions. A difference in lifetime between nuclei that are polarized in the east and west direction is searched for. This difference is maximally sensitive to the rotation of the Earth, while the sidereal dependence is free from most systematic errors. Results: The experiment sets a limit of 2 x 10(-4) at 90% C.L. on the amplitude of the sidereal variation of the relative lifetime differences, an improvement by a factor 15 compared to an earlier result. Conclusions: No significant violation of Lorentz invariance is found. The result sets limits on parameters of theories describing Lorentz-invariance violation.

Background: Lorentz invariance is key in our understanding of nature, yet relatively few experiments have tested Lorentz invariance in weak interactions.Purpose: Our goal is to obtain limits on Lorentz-invariance violation in weak interactions, in particular rotational invariance in beta decay.Method: We search for a dependence of the lifetime of Na-20 nuclei on the nuclear spin direction. Such directional dependence would be evidence for Lorentz-invariance violation in weak interactions. A difference in lifetime between nuclei that are polarized in the east and west direction is searched for. This difference is maximally sensitive to the rotation of the Earth, while the sidereal dependence is free from most systematic errors.Results: The experiment sets a limit of 2 x 10(-4) at 90% C.L. on the amplitude of the sidereal variation of the relative lifetime differences, an improvement by a factor 15 compared to an earlier result.Conclusions: No significant violation of Lorentz invariance is found. The result sets limits on parameters of theories describing Lorentz-invariance violation.

The 1s-2s interval has been measured in the muonium ({$\mu^+e^-$}) atom by Doppler-free two-photon laser spectroscopy. The frequency separation of the states was determined to be 2 455 528 941.0(9.8) MHz in good agreement with quantum electrodynamics. The muon-electron mass ratio can be extracted and is found to be 206.768 38(17). The result may be interpreted as measurement of the muon-electron charge ratio as $-1- 1.1(2.1)\cdot 10^{-9}$.

The 1s-2s energy interval in the muonium (μ+e-) atom has been measured by Doppler-free two-photon laser spectroscopy. A value of 2 455 528 941.0(9.8) MHz has been obtained in good agreement with quantum electrodynamics (QED). The muon-electron mass ratio can be extracted and is found to be 296.768 38(17). The measurement may also be interpreted as a determination of the muon-electron charge ratio as - 1 - 1.1(2.1)·10-9. Corresponding measurements in deuterium using the same experimental setup confirmed the validity of the applied analysis procedure.

A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.

Transition frequencies between low-lying energy levels in a single trapped $^{138}$Ba$^{+}$ ion have been measured with laser spectroscopy referenced to an optical frequency comb. By extracting the frequencies of one-photon and two-photon components of the line shape using an eight-level optical Bloch model, we achieved 0.1 MHz accuracy for the 5d $^{2}$D$_{3/2}$ - 6p $^{2}$P$_{1/2}$ and 6s $^{2}$S$_{1/2}$ - 5d $^{2}$D$_{3/2}$ transition frequencies, and 0.2 MHz for the 6s $^{2}$S$_{1/2}$ - 6p $^{2}$P$_{1/2}$ transition frequency., 5 pages, 7 figures, submitted to Phys. Rev. A

The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval

The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 Collaboration reduces the uncertainty on the world average of a_mu to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly., Plenary Talk; PANIC'02 XVI Particles and Nuclear International Conference, Osaka, Japan; Sept. 30 - Oct. 4, 2002; Report describes the published 0.7 ppm result and updates the theory status

In the singly charged Ra+ ion the contributions of the weak interactions to the atomic level energies are some 50 times larger than in the Cs atom. We report the results of laser spectroscopy experiments on Ra-209-214(+) isotopes in preparation of a precision atomic parity violation experiment. Experimental input data is provided for testing the atomic theory, which is necessary for a competitive extraction of the Weinberg angle at low energies.

Ongoing experiments and projects to test our understanding of fundamental inter- actions and symmetries in nature have progressed significantly in the past few years. At high energies the long searched for Higgs boson has been found; tests of gravity for antimatter have come closer to reality; Lorentz invariance - up to now very well tested in electromag- netic interactions - is now being challenged in dedicated experiments in weak interactions as well; discrete symmetries are scrutinized in experiments on C, P, T, CP, and CPT through searches for permanent electric dipole moments and precise measurements of atomic parity violation and in precision measurements involving antiprotons; a new generation of pre- cise flavor symmetry tests is coming up; and last but not least precision measurements of Standard Model values of im portant fundamental constants and quan tities such as the muon magnetic anomaly are underway. All the ongoing projects in this most active field have a robust potential for discovery of New Physics, i.e. physics not yet covered by the well estab- lished Standard Model of particle physics. Antip rotons have a central position in this lively field with many new and novel upcoming experiments and facilities

The 1+/2 -> 1+/2 superallowed mixed mirror decay of Ne-19 to F-19 is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T-1/2 = 17.2832 +/- 0.0051((stat)) +/- 0.0066((syst)) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.

The 1+/2 -> 1+/2 superallowed mixed mirror decay of Ne-19 to F-19 is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T-1/2 = 17.2832 +/- 0.0051((stat)) +/- 0.0066((syst)) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.

The 1+/2 -> 1+/2 superallowed mixed mirror decay of Ne-19 to F-19 is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T-1/2 = 17.2832 +/- 0.0051((stat)) +/- 0.0066((syst)) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.

A measurement of the final state distribution of the B-8 beta decay, obtained by implanting a 8B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyvaskyla [O. S. Kirsebom et al., Phys. Rev. C 83, 065802 ( 2011)]. It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.

Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the 6d(2)D(3/2)-7p(2)P(1/2) transition in Ra-209-214(+), which are sensitive to the short-range part of the atomic wave functions, were measured. The results are essential experimental input for improving the precision of atomic structure calculations. This is indispensable for parity violation in Ra+ aiming at the determination of the weak mixing angle.

Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the 6d(2)D(3/2)-7p(2)P(1/2) transition in Ra-209-214(+), which are sensitive to the short-range part of the atomic wave functions, were measured. The results are essential experimental input for improving the precision of atomic structure calculations. This is indispensable for parity violation in Ra+ aiming at the determination of the weak mixing angle.

The hyperfine structure of short-lived trapped Ra-211,209(+) ions was investigated by means of laser spectroscopy. The hyperfine structure constants A and B of the 6d(2)D(3/2) level were determined. There is a 2.2 standard deviation difference between the theoretical and the more accurate experimental value for the B coefficient of Ra-211(+). These measurements provide a test for the atomic theory required for upcoming experiments on atomic parity violation and atomic clocks. (C) 2011 Elsevier B.V. All rights reserved.

The hyperfine structure of short-lived trapped Ra-211,209(+) ions was investigated by means of laser spectroscopy. The hyperfine structure constants A and B of the 6d(2)D(3/2) level were determined. There is a 2.2 standard deviation difference between the theoretical and the more accurate experimental value for the B coefficient of Ra-211(+). These measurements provide a test for the atomic theory required for upcoming experiments on atomic parity violation and atomic clocks. (C) 2011 Elsevier B.V. All rights reserved.

Atomic parity violation (APV) can be measured in a single Ra(+) ion, enabling a precise measurement of the electroweak mixing angle in the Standard Model of particle physics at low momentum transfer. This provides sensitivity to new particles such as extra Z(0) bosons or leptoquarks. The Weinberg angle can be measured via a determination of the light shift in the forbidden 7(2)S(1/2)-6(2)D(3/2) transition in a single trapped Ra(+). Ultra-narrow transitions in such an ideal system can also be exploited to realize a high stability frequency standard. At the TRI mu P facility of KVI, we have succeeded in the production of a series of radioactive short-lived radium isotopes. The radium isotopes produced were stopped and thermalized to Ra(+) in a thermal ionizer, mass separated in a Wien filter, cooled in a gas filled radio frequency quadrupole and subsequently trapped as a cloud in a linear Paul trap. Laser spectroscopy in the trapped radium ions has been performed. The results of hyperfine structure, isotope shift, and lifetime measurements are important experimental inputs to test the accuracy of atomic theory, the precision of which is indispensable for extracting the Weinberg angle. These results are also of relevance for a possible atomic clock, based on trapped Ra(+).

Atomic parity violation (APV) can be measured in a single Ra(+) ion, enabling a precise measurement of the electroweak mixing angle in the Standard Model of particle physics at low momentum transfer. This provides sensitivity to new particles such as extra Z(0) bosons or leptoquarks. The Weinberg angle can be measured via a determination of the light shift in the forbidden 7(2)S(1/2)-6(2)D(3/2) transition in a single trapped Ra(+). Ultra-narrow transitions in such an ideal system can also be exploited to realize a high stability frequency standard. At the TRI mu P facility of KVI, we have succeeded in the production of a series of radioactive short-lived radium isotopes. The radium isotopes produced were stopped and thermalized to Ra(+) in a thermal ionizer, mass separated in a Wien filter, cooled in a gas filled radio frequency quadrupole and subsequently trapped as a cloud in a linear Paul trap. Laser spectroscopy in the trapped radium ions has been performed. The results of hyperfine structure, isotope shift, and lifetime measurements are important experimental inputs to test the accuracy of atomic theory, the precision of which is indispensable for extracting the Weinberg angle. These results are also of relevance for a possible atomic clock, based on trapped Ra(+).