A. Gorelov

Specific mass shift measurements in rubidium by Doppler-free two-photon transitions

We measured the isotope shifts between Rb isotopes (86m, 86g, 81) and 87Rb for the 5S1/2 to 5D5/2 transition using the Doppler-free two-photon transition technique. By making a King plot, the difference between the specific mass shift constants of the 5S1/2 and 5D5/2 states is deduced to be 77(33) GHz amu. In addition, we measured the hyperfine constants of the 5D5/2 states in those three Rb isotopes, and we have determined an improved ground state hyperfine constant in 86mRb, A(5S1/2) = 563.04(5) MHz.

Precision measurement of the nuclear polarization in laser-cooled, optically pumped 37 K

We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37K atoms which will allow us to precisely measure angular correlation parameters in the -decay of the same atoms. These results will be used to test the V − A framework of the weak interaction at high precision. At the Triumf neutral atom trap (Trinat), a magneto-optical trap confines and cools neutral 37K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of , which is significantly more precise than previous measurements with this technique. Since our current measurement of the β-asymmetry has statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to , allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.

PCTFE as a solution to birefringence in atom trap viewports

We have developed and characterized optical viewports with the glass-to-metal seal made by the plastic PCTFE (polychlorotrifluoroethylene). The goal is to reduce stress-induced birefringence while maintaining ultra-high vacuum compatibility. We have maintained a Stokes parameter S3 of 0.9986, and achieved <5 × 10(-11) Torr partial pressure of air. We have also measured the diffusion and permeation of helium through PCTFE and placed upper limits on nitrogen, oxygen, and argon permeation, as PCTFE has been suggested as an o-ring for transport of environmental noble gas samples, though we know of no other noble gas measurements.

The β+ decay of 37K as a multi‐faceted probe of fundamental physics

Precision β decay experiments represent an important and complimentary approach to high‐energy searches for physics outside the “Standard Model”, our current understanding of fundamental particles and their interactions. The mirror decay of 37K provides an excellent probe with which to search for new physics. The ft value of this (as well as other T = 1/2 mirror transitions) can be used to provide a measurement of the value of the Vud element of the CKM mass‐mixing matrix, complementing the value obtained from superallowed pure Fermi decays. In addition, the polarized angular distribution parameters are sensitive to a variety of possible new physics: the β and ν asymmetries can be used to search for right‐handed currents in the charged weak interaction, and their energy‐dependences are sensitive to second‐class currents forbidden in the Standard Model. Time‐reversal symmetry can also be tested by a precision measurement of the triple‐vector correlation between the initial nuclear spin and the momenta of t...