14 research outputs found
Determination of transition frequencies in a single Ba ion
Transition frequencies between low-lying energy levels in a single trapped
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 D - 6p
P and 6s S - 5d D transition
frequencies, and 0.2 MHz for the 6s S - 6p P
transition frequency.Comment: 5 pages, 7 figures, submitted to Phys. Rev.
First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei
A new test of Lorentz invariance in the weak interactions has been made by
searching for variations in the decay rate of spin-polarized 20Na nuclei. This
test is unique to Gamow-Teller transitions, as was shown in the framework of a
recently developed theory that assumes a Lorentz symmetry breaking background
field of tensor nature. The nuclear spins were polarized in the up and down
direction, putting a limit on the amplitude of sidereal variations of the form
|(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}.
This measurement shows a possible route toward a more detailed testing of
Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure
A gas cell for stopping, storing and polarizing radioactive particles
A radioactive beam of 20Na is stopped in a gas cell filled with Ne gas. The
stopped particles are polarized by optical pumping. The degree of polarization
that can be achieved is studied. A maximum polarization of 50% was found. The
dynamic processes in the cell are described with a phenomenological model.Comment: 16 pages, 6 figure