Detailed structure of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Sn</mml:mi><mml:mprescripts/><mml:none/><mml:mn>131</mml:mn></mml:mmultiscripts></mml:math> populated in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>β</mml:mi></mml:math> decay of isomerically purified <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>In</mml:mi><mml:mprescripts/><mml:none/><mml:mn>131</mml:mn></mml:mmultiscripts></mml:math> states
Bibliographic record
Abstract
The excited structure of the single-hole nucleus Sn 131 populated by the β − decay of In 131 was investigated in detail at the ISOLDE facility at CERN. This new experiment took advantage of isomeric purification capabilities provided by resonant ionization, making it possible to independently study the decay of each isomer for the first time. The position of the first-excited ν h 11 / 2 neutron-hole state was confirmed via an independent mass spectroscopy experiment performed at the Ion Guide Isotope Separator On-Line facility at the University of Jyväskylä. The level scheme of Sn 131 was notably expanded with the addition of 31 new γ -ray transitions and 22 new excited levels. The γ -emitting excited levels above the neutron separation energy in Sn 131 were investigated, revealing a large number of states, which in some cases decay by transitions to other neutron-unbound states. Our analysis showed the dependence between the population of these states in Sn 131 and the β -decaying In 131 state feeding them. Profiting from the isomer selectivity, it was possible to estimate the direct β feeding to the 3 / 2 + ground and 11 / 2 − isomeric states, disentangling the contributions from the three indium parent states. This made possible to resolve the discrepancies in log f t for first-forbidden transitions observed in previous studies, and to determine the β -delayed neutron decay probability ( P n ) values of each indium isomers independently. The first measurement of subnanosecond lifetimes in Sn 131 was performed in this work. A short T 1 / 2 = 18 ( 4 ) − ps value was measured for the 1 / 2 + neutron single-hole 332-keV state, which indicates an enhanced l -forbidden M 1 behavior for the ν 3 s 1 / 2 − 1 → ν 3 d 3 / 2 − 1
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.004 | 0.001 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.547 | 0.457 |
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".