Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam
Bibliographic record
Abstract
T2K reports its first measurements of the parameters governing the disappearance of ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ survival probability is expected to be minimal. Using a data set corresponding to $4.01\ifmmode\times\else\texttimes\fi{}{10}^{20}$ protons on target, 34 fully contained $\ensuremath{\mu}$-like events were observed. The best-fit oscillation parameters are ${\mathrm{sin}}^{2}({\overline{\ensuremath{\theta}}}_{23})=0.45$ and $|\mathrm{\ensuremath{\Delta}}{\overline{m}}_{32}^{2}|=2.51\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{eV}}^{2}$ with 68% confidence intervals of $0.38--0.64$ and $2.26--2.80\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{eV}}^{2}$, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ disappearance parameters measured by T2K.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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".