59 research outputs found
Precision Measurement of Time-Reversal Symmetry Violation with Laser-Cooled Polyatomic Molecules
Precision searches for time-reversal symmetry violating interactions in polar
molecules are extremely sensitive probes of high energy physics beyond the
Standard Model. To extend the reach of these probes into the PeV regime, long
coherence times and large count rates are necessary. Recent advances in laser
cooling of polar molecules offer one important tool -- optical trapping.
However, the types of molecules that have been laser-cooled so far do not have
the highly desirable combination of features for new physics searches, such as
the ability to fully polarize and the existence of internal co-magnetometer
states. We show that by utilizing the internal degrees of freedom present only
in molecules with at least three atoms, these features can be attained
simultaneously with molecules that have simple structure and are amenable to
laser cooling and trapping
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
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Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron
The Standard Model of particle physics is known to be incomplete. Extensions to the Standard Model, such as weak-scale supersymmetry, posit the existence of new particles and interactions that are asymmetric under time reversal (T) and nearly always predict a small yet potentially measurable electron electric dipole moment (EDM), d_e, in the range of 10^(ā27) to 10^(ā30) eĀ·cm. The EDM is an asymmetric charge distribution along the electron spin (S) that is also asymmetric under T. Using the polar molecule thorium monoxide, we measured d_e = (ā2.1Ā±3.7_(stat)Ā±2.5_(syst)) Ć 10ā29 eĀ·cm. This corresponds to an upper limit of ād_eā < 8.7 Ć 10^(ā29) eĀ·cm with 90% confidence, an order of magnitude
improvement in sensitivity relative to the previous best limit. Our result constrains T-violating physics at the TeV energy scale
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