First Penning trap mass measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Ca</mml:mi><mml:mprescripts/><mml:none/><mml:mn>36</mml:mn></mml:mmultiscripts></mml:math>
Bibliographic record
Abstract
Background: Isobaric quintets provide the best test of the isobaric multiplet mass equation (IMME) and can uniquely identify higher order corrections suggestive of isospin symmetry breaking effects in the nuclear Hamiltonian. The generalized IMME (GIMME) is a novel microscopic interaction theory that predicts an extension to the quadratic form of the IMME. Only the $A=20,32$ $T=2$ quintets have the exotic ${T}_{z}=\ensuremath{-}2$ member ground state mass determined to high precision by Penning trap mass spectrometry.Purpose: We aim to establish $A=36$ as the third $T=2$ isobaric quintet with the ${T}_{z}=\ensuremath{-}2$ member ground state mass measured by Penning trap mass spectrometry and provide the first test of the predictive power of the GIMME.Method: A radioactive beam of neutron-deficient $^{36}\mathrm{Ca}$ was produced by projectile fragmentation at the National Superconducting Cyclotron Laboratory. The beam was thermalized and the masses of $^{36}\mathrm{Ca}^{+}$ and $^{36}\mathrm{Ca}^{2+}$ were measured by the time-of-flight ion cyclotron resonance method in the LEBIT 9.4 T Penning trap.Results: We measure the mass excess of $^{36}\mathrm{Ca}$ to be $\mathrm{ME}=\ensuremath{-}6483.6(56)$ keV, an improvement in precision by a factor of 6 over the literature value. The new datum is considered together with evaluated nuclear data on the $A=36$, $T=2$ quintet. We find agreement with the quadratic form of the IMME given by isospin symmetry, but only coarse qualitative agreement with predictions of the GIMME.Conclusion: A total of three isobaric quintets have their most exotic members measured by Penning trap mass spectrometry. The GIMME predictions in the $T=2$ quintet appear to break down for $A=32$ and greater.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".