202 research outputs found
Magnetic and electric dipole moments of the state in ThO
The metastable state in the thorium monoxide (ThO)
molecule is highly sensitive to the presence of a CP-violating permanent
electric dipole moment of the electron (eEDM). The magnetic dipole moment
and the molecule-fixed electric dipole moment of this state are
measured in preparation for a search for the eEDM. The small magnetic moment
displays the predicted cancellation of
spin and orbital contributions in a paramagnetic molecular
state, providing a significant advantage for the suppression of magnetic field
noise and related systematic effects in the eEDM search. In addition, the
induced electric dipole moment is shown to be fully saturated in very modest
electric fields ( 10 V/cm). This feature is favorable for the suppression of
many other potential systematic errors in the ThO eEDM search experiment.Comment: 4 pages, 3 figure
Frequency-doubled Nd:YAG MOPA laser system with programmable rectangular pulses up to 200 microseconds
A compact frequency-doubled diode-pumped Nd:YAG master-oscillator
power-amplifier laser system with programmable microsecond pulse length has
been developed. Analog pulse shaping of the output from a single-frequency
continuous-wave Nd:YAG oscillator, and subsequent amplification, allowed the
generation of rectangular pulses with pulse lengths on the order of the Nd:YAG
fluorescence lifetime. Temporally flat-top pulses of 1064 nm light with 520 mJ
pulse energy, 2.6 kW peak power, and 200 s duration, with linewidth below
10 kHz, were obtained at a repetition rate of 2 Hz. Second harmonic generation
in a LBO crystal yielded pulses of 262 mJ and 1.3 kW peak power at 532 nm. The
peak power can be maintained within 2.9% over the duration of the laser pulse,
and long-term intensity stability of 1.1% was observed. The spatially flat-top
beam at 1064 nm used in the amplifier is converted to a Gaussian beam at 532 nm
with beam quality factor during the second harmonic generation.
This system has potential as a pump source for Ti:sapphire, dye, or optical
parametric amplifiers to generate tunable high-power single-frequency radiation
for applications in precision measurements and laser slowing.Comment: 9 pages, 5 figure
Deceleration of a supersonic beam of SrF molecules to 120 m/s
We report on the deceleration of a beam of SrF molecules from 290 to 120~m/s.
Following supersonic expansion, the molecules in the (, )
low-field seeking states are trapped by the moving potential wells of a
traveling-wave Stark decelerator. With a deceleration strength of 9.6 km/s
we have demonstrated the removal of 85 % of the initial kinetic energy in a 4
meter long modular decelerator. The absolute amount of kinetic energy removed
is a factor 1.5 higher compared to previous Stark deceleration experiments. The
demonstrated decelerator provides a novel tool for the creation of highly
collimated and slow beams of heavy diatomic molecules, which serve as a good
starting point for high-precision tests of fundamental physics
Search for the electric dipole moment of the electron with thorium monoxide
The electric dipole moment of the electron (eEDM) is a signature of
CP-violating physics beyond the Standard Model. We describe an ongoing
experiment to measure or set improved limits to the eEDM, using a cold beam of
thorium monoxide (ThO) molecules. The metastable state in ThO
has important advantages for such an experiment. We argue that the statistical
uncertainty of an eEDM measurement could be improved by as much as 3 orders of
magnitude compared to the current experimental limit, in a first-generation
apparatus using a cold ThO beam. We describe our measurements of the state
lifetime and the production of ThO molecules in a beam, which provide crucial
data for the eEDM sensitivity estimate. ThO also has ideal properties for the
rejection of a number of known systematic errors; these properties and their
implications are described.Comment: v2: Equation (11) correcte
Shot-noise-limited spin measurements in a pulsed molecular beam
Heavy diatomic molecules have been identified as good candidates for use in
electron electric dipole moment (eEDM) searches. Suitable molecular species can
be produced in pulsed beams, but with a total flux and/or temporal evolution
that varies significantly from pulse to pulse. These variations can degrade the
experimental sensitivity to changes in spin precession phase of an electri-
cally polarized state, which is the observable of interest for an eEDM
measurement. We present two methods for measurement of the phase that provide
immunity to beam temporal variations, and make it possible to reach
shot-noise-limited sensitivity. Each method employs rapid projection of the
spin state onto both components of an orthonormal basis. We demonstrate both
methods using the eEDM-sensitive H state of thorium monoxide (ThO), and use one
of them to measure the magnetic moment of this state with increased accuracy
relative to previous determinations.Comment: 12 pages, 6 figure
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