Long-distance nuclear matrix elements for neutrinoless double-beta decay from lattice QCD
Bibliographic record
Abstract
Neutrinoless double-beta (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mn>0</a:mn><a:mi>ν</a:mi><a:mi>β</a:mi><a:mi>β</a:mi></a:math>) decay is a heretofore unobserved process which, if observed, would imply that neutrinos are Majorana particles. Interpretations of the stringent experimental constraints on <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mn>0</c:mn><c:mi>ν</c:mi><c:mi>β</c:mi><c:mi>β</c:mi></c:math>-decay half-lives require calculations of nuclear matrix elements. This work presents the first lattice quantum chromodynamics (LQCD) calculation of the matrix element for <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mn>0</e:mn><e:mi>ν</e:mi><e:mi>β</e:mi><e:mi>β</e:mi></e:math> decay in a multinucleon system, specifically the <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>n</g:mi><g:mi>n</g:mi><g:mo stretchy="false">→</g:mo><g:mi>p</g:mi><g:mi>p</g:mi><g:mi>e</g:mi><g:mi>e</g:mi></g:math> transition, mediated by a light left-handed Majorana neutrino propagating over nuclear-scale distances. This calculation is performed with quark masses corresponding to a pion mass of <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:msub><j:mi>m</j:mi><j:mi>π</j:mi></j:msub><j:mo>=</j:mo><j:mn>806</j:mn><j:mtext> </j:mtext><j:mtext> </j:mtext><j:mi>MeV</j:mi></j:math> at a single lattice spacing and volume. The statistically cleaner <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:msup><l:mi mathvariant="normal">Σ</l:mi><l:mo>−</l:mo></l:msup><l:mo stretchy="false">→</l:mo><l:msup><l:mi mathvariant="normal">Σ</l:mi><l:mo>+</l:mo></l:msup><l:mi>e</l:mi><l:mi>e</l:mi></l:math> transition is also computed in order to investigate various systematic uncertainties. The prospects for matching the results of LQCD calculations onto a nuclear effective field theory to determine a leading-order low-energy constant relevant for <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:mn>0</q:mn><q:mi>ν</q:mi><q:mi>β</q:mi><q:mi>β</q:mi></q:math> decay with a light Majorana neutrino are investigated. This work, therefore, sets the stage for future calculations at physical values of the quark masses that, combined with effective field theory and nuclear many-body studies, will provide controlled theoretical inputs to experimental searches of <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mn>0</s:mn><s:mi>ν</s:mi><s:mi>β</s:mi><s:mi>β</s:mi></s:math> decay. 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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.004 |
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 teacher head, 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".