Towards atomic parity violation at the francium trapping facility
Bibliographic record
Abstract
The development of the Francium Trapping Facility at TRIUMF, Canada and progress towards an atomic parity violation measurement in francium are underway. Francium (Z = 87) is the heaviest alkali. Its simple atomic structure and large number of nucleons make it an attractive system for weak interaction studies. For this reason, atomic parity violation in francium is an active area of study, and recent years have seen significant progress towards that end. Laser trapping of francium at Triumf has only recently been achieved, and several useful physics measurements for the future atomic parity violation experiment have been performed. The future measurement is of the highly forbidden 7S - 8S optical transition amplitude, which is suppressed by ~ 10^10 compared to an allowed transition amplitude. This will be achieved by interference with an allowed Stark transition, similar to the 6S - 7S optical atomic parity violation measurement in cesium. The commissioning of the two-chamber trapping apparatus as well as the development of the electric field plates for the Stark interference will be reported on. The physics measurements include the photoionization cross-section from the 7P_3/2 states, and isotope shifts of the D1 line. The cross-section must be known to evaluate a potential atom loss mechanism from the 506 nm light of the 7S - 8S excitation, negatively impacting the trapped population. Atomic theory calculations, which are required for the extraction of the weak coupling constants from the atomic measurement, may be benchmarked against these isotope shifts, allowing theorists to refine their techniques for the more sensitive evaluations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".