Mass measurements of isotopes of Nb, Mo, Tc, Ru, and Rh along the νp- and rp-process paths using the Canadian Penning trap mass spectrometer
Bibliographic record
Abstract
The reaction paths of two proposed nucleosynthetic processes on the proton-rich side of stability, the $rp$ and $\ensuremath{\nu}p$ processes, pass through a region of isotopes between Mo and Pd where masses had long gone unmeasured. Precise knowledge of the paths and final abundances of these two processes has been limited by the corresponding lack of precision in the proton-separation energies ${S}_{p}$ when derived from extrapolated masses. The masses of 18 neutron-deficient isotopes of Nb, Mo, Tc, Ru, and Rh have been measured using the Canadian Penning trap mass spectrometer. Three of the masses presented, ${}^{90}$Mo, ${}^{91}$Mo, and ${}^{93}$Tc, provide the first direct measurement of the masses of these nuclides, and the others provide confirmation of recent measurements using other Penning traps. Included in this work is a measurement of the mass of ${}^{87}$Mo, which differs by $3.7\ensuremath{\sigma}$ from the mass presented in the 2003 Atomic Mass Evaluation. This leads to a change in the ${S}_{p}$ value of ${}^{88}$Tc which reduces the suppression of flow of the $\ensuremath{\nu}p$-process path through ${}^{87}$Mo($p,\ensuremath{\gamma}$)${}^{88}$Tc reported following the mass measurement of ${}^{88}$Tc [C. Weber et al., Phys. Rev. C 78, 054310 (2008)]. This in turn affects the resulting $\ensuremath{\nu}p$-process abundances.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".