High-resolution hypernuclear spectroscopy at Jefferson Lab, Hall A
Bibliographic record
Abstract
The experiment E94-107 in Hall A at Jefferson Lab started a systematic study of high-resolution hypernuclear spectroscopy in the $0p$-shell region of nuclei such as the hypernuclei produced in electroproduction on $^{9}\mathrm{Be},\phantom{\rule{0.16em}{0ex}}^{12}\mathrm{C}$, and $^{16}\mathrm{O}$ targets. In order to increase counting rates and provide unambiguous kaon identification, two superconducting septum magnets and a ring-imaging Cherenkov detector were added to the Hall A standard equipment. The high-quality beam, the good spectrometers, and the new experimental devices allowed us to obtain very good results. For the first time, measurable strength with sub-MeV energy resolution was observed for the core-excited states of $_{\phantom{\rule{3.33333pt}{0ex}}\mathrm{\ensuremath{\Lambda}}}^{12}\mathrm{B}$. A high-quality $_{\phantom{\rule{3.33333pt}{0ex}}\mathrm{\ensuremath{\Lambda}}}^{16}\mathrm{N}$ hypernuclear spectrum was likewise obtained. A first measurement of the $\mathrm{\ensuremath{\Lambda}}$ binding energy for $_{\phantom{\rule{3.33333pt}{0ex}}\mathrm{\ensuremath{\Lambda}}}^{16}\mathrm{N}$, calibrated against the elementary reaction on hydrogen, was obtained with high precision, $13.76\ifmmode\pm\else\textpm\fi{}0.16$ MeV. Similarly, the first $_{\mathrm{\ensuremath{\Lambda}}}^{9}\mathrm{Li}$ hypernuclear spectrum shows general agreement with theory (distorted-wave impulse approximation with the SLA and BS3 electroproduction models and shell-model wave functions). Some disagreement exists with respect to the relative strength of the states making up the first multiplet. A $\mathrm{\ensuremath{\Lambda}}$ separation energy of 8.36 MeV was obtained, in agreement with previous results. It has been shown that the electroproduction of hypernuclei can provide information complementary to that obtained with hadronic probes and the $\ensuremath{\gamma}$-ray spectroscopy technique.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".