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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Sn</a:mi><a:mprescripts/><a:none/><a:mn>131</a:mn></a:mmultiscripts></a:math> populated by the <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msup><b:mi>β</b:mi><b:mo>−</b:mo></b:msup></b:math> decay of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mmultiscripts><c:mi>In</c:mi><c:mprescripts/><c:none/><c:mn>131</c:mn></c:mmultiscripts></c:math> 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 <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mi>ν</d:mi><d:msub><d:mi>h</d:mi><d:mrow><d:mn>11</d:mn><d:mo>/</d:mo><d:mn>2</d:mn></d:mrow></d:msub></d:mrow></d:math> 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 <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mmultiscripts><e:mi>Sn</e:mi><e:mprescripts/><e:none/><e:mn>131</e:mn></e:mmultiscripts></e:math> was notably expanded with the addition of 31 new <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mi>γ</f:mi></f:math>-ray transitions and 22 new excited levels. The <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mi>γ</g:mi></g:math>-emitting excited levels above the neutron separation energy in <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"><h:mmultiscripts><h:mi>Sn</h:mi><h:mprescripts/><h:none/><h:mn>131</h:mn></h:mmultiscripts></h:math> 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 <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"><i:mmultiscripts><i:mi>Sn</i:mi><i:mprescripts/><i:none/><i:mn>131</i:mn></i:mmultiscripts></i:math> and the <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"><j:mi>β</j:mi></j:math>-decaying <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"><k:mmultiscripts><k:mi>In</k:mi><k:mprescripts/><k:none/><k:mn>131</k:mn></k:mmultiscripts></k:math> state feeding them. Profiting from the isomer selectivity, it was possible to estimate the direct <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"><l:mi>β</l:mi></l:math> feeding to the <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"><m:mrow><m:mn>3</m:mn><m:mo>/</m:mo><m:msup><m:mn>2</m:mn><m:mo>+</m:mo></m:msup></m:mrow></m:math> ground and <n:math xmlns:n="http://www.w3.org/1998/Math/MathML"><n:mrow><n:mn>11</n:mn><n:mo>/</n:mo><n:msup><n:mn>2</n:mn><n:mo>−</n:mo></n:msup></n:mrow></n:math> isomeric states, disentangling the contributions from the three indium parent states. This made possible to resolve the discrepancies in <o:math xmlns:o="http://www.w3.org/1998/Math/MathML"><o:mrow><o:mi>log</o:mi><o:mi>f</o:mi><o:mi>t</o:mi></o:mrow></o:math> for first-forbidden transitions observed in previous studies, and to determine the <p:math xmlns:p="http://www.w3.org/1998/Math/MathML"><p:mi>β</p:mi></p:math>-delayed neutron decay probability <q:math xmlns:q="http://www.w3.org/1998/Math/MathML"><q:mo>(</q:mo><q:msub><q:mi>P</q:mi><q:mi>n</q:mi></q:msub><q:mo>)</q:mo></q:math> values of each indium isomers independently. The first measurement of subnanosecond lifetimes in <r:math xmlns:r="http://www.w3.org/1998/Math/MathML"><r:mmultiscripts><r:mi>Sn</r:mi><r:mprescripts/><r:none/><r:mn>131</r:mn></r:mmultiscripts></r:math> was performed in this work. A short <s:math xmlns:s="http://www.w3.org/1998/Math/MathML"><s:msub><s:mi>T</s:mi><s:mrow><s:mn>1</s:mn><s:mo>/</s:mo><s:mn>2</s:mn></s:mrow></s:msub><s:mo>=</s:mo><s:mn>18</s:mn><s:mo>(</s:mo><s:mn>4</s:mn><s:mo>)</s:mo><s:mtext>−</s:mtext><s:mi>ps</s:mi></s:math> value was measured for the <t:math xmlns:t="http://www.w3.org/1998/Math/MathML"><t:mrow><t:mn>1</t:mn><t:mo>/</t:mo><t:msup><t:mn>2</t:mn><t:mo>+</t:mo></t:msup></t:mrow></t:math> neutron single-hole 332-keV state, which indicates an enhanced <u:math xmlns:u="http://www.w3.org/1998/Math/MathML"><u:mi>l</u:mi></u:math>-forbidden <v:math xmlns:v="http://www.w3.org/1998/Math/MathML"><v:mrow><v:mi>M</v:mi><v:mn>1</v:mn></v:mrow></v:math> behavior for the <w:math xmlns:w="http://www.w3.org/1998/Math/MathML"><w:mrow><w:mi>ν</w:mi><w:mn>3</w:mn><w:msubsup><w:mi>s</w:mi><w:mrow><w:mn>1</w:mn><w:mo>/</w:mo><w:mn>2</w:mn></w:mrow><w:mrow><w:mo>−</w:mo><w:mn>1</w:mn></w:mrow></w:msubsup><w:mo>→</w:mo><w:mi>ν</w:mi><w:mn>3</w:mn><w:msubsup><w:mi>d</w:mi><w:mrow><w:mn>3</w:mn><w:mo>/</w:mo><w:mn>2</w:mn></w:mrow><w:mrow><w:mo>−</w:mo><w:mn>1</w:mn></w:mrow></w:msubsup></w:mrow></w:math> transition. The measured half-lives of high-energy states populated in the <x:math xmlns:x="http://www.w3.org/1998/Math/MathML"><x:mi>β</x:mi></x:math> decay of the <y:math xmlns:y="http://www.w3.org/1998/Math/MathML"><y:mrow><y:mo>(</y:mo><y:mn>21</y:mn><y:mo>/</y:mo><y:msup><y:mn>2</y:mn><y:mo>+</y:mo></y:msup><y:mo>)</y:mo></y:mrow></y:math> second isomeric state <z:math xmlns:z="http://www.w3.org/1998/Math/MathML"><z:mo>(</z:mo><z:mmultiscripts><z:mi>In</z:mi><z:mprescripts/><z:none/><z:mrow><z:mn>131</z:mn><z:mi>m</z:mi><z:mn>2</z:mn></z:mrow></z:mmultiscripts><z:mo>)</z:mo></z:math> provided valuable information on transition rates, supporting the interpretation of these levels as core-excited states analogous to those observed in the doubly-magic <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML"><ab:mmultiscripts><ab:mi>Sn</ab:mi><ab:mprescripts/><ab:none/><ab:mn>132</ab:mn></ab:mmultiscripts></ab:math>. Published by the American Physical Society 2024
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.006 | 0.004 |
| Meta-epidemiology (narrow) | 0.005 | 0.006 |
| Meta-epidemiology (broad) | 0.003 | 0.008 |
| Bibliometrics | 0.002 | 0.005 |
| Science and technology studies | 0.004 | 0.006 |
| Scholarly communication | 0.004 | 0.005 |
| Open science | 0.009 | 0.008 |
| Research integrity | 0.004 | 0.009 |
| Insufficient payload (model declined to judge) | 0.008 | 0.007 |
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; both teacher heads agree on what is shown here.
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".