Spectroscopy with trapped francium: advances and perspectives for weak interaction studies

Abstract

Francium is a candidate for atomic parity non-conservation (PNC) experiments. Its simple atomic structure has been the subject of extensive experimental research facilitated by the ability to trap and cool significant numbers of atoms. The studies include the location of energy levels, their hyperfine splittings and their lifetime. All of these levels are close to the ground state. The results show a remarkable agreement with calculated ab initio properties to a degree that is comparable with other stable alkali atoms. The quantitative understanding of francium has made possible the exploration of avenues for a PNC measurement in the optical and the microwave regimes. These precision experiments have the potential to enhance our understanding of the weak coupling constants between electrons and nucleons, as well as between nucleons.

Parity Violation and Electric Dipole Moments in Atoms and Molecules

“…Experiments on isotope chains are in progress at Berkeley for Dy and Yb atoms, 31,32 at TRIUMF for Fr atoms, 14 at Los Alamos for Yb + ions, 33 and at Groningen (KVI) for Ra + ions. 17 There is an interesting recent suggestion to measure the PNC in metastable Xe and Hg.…”

Quantum electrodynamics corrections to energies, transition amplitudes, and parity nonconservation in Rb, Cs, Ba+, Tl, Fr, and Ra+

“…The FrPNC collaboration has begun the construction of a laser cooling and trapping apparatus at the TRIUMF laboratories in Canada with the purpose of measuring atomic parity nonconservation in artificially produced francium [17]. With a PNC amplitude expected to be around 15 times larger than that of cesium, and its relatively simple electronic configuration which leads to accurate calculations, francium is an ideal atom for precision measurements of PNC [18][19][20].…”

Proposed Experiment for the Measurement of the Anapole Moment in Francium

“…39 Fr is, however, an unstable element and it is necessary to use an accelerator to produce it in a fusion or fission reaction 40 or take from the decay process of thorium. 41 The program presented in this contribution relies on the laser trapping an cooling techniques that can capture enough atoms for performing the measurement.…”