Measurement of the spin of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Ξ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>1530</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>resonance
Bibliographic record
Abstract
The properties of the $\ensuremath{\Xi}(1530)$ resonance are investigated in the ${\ensuremath{\Lambda}}_{c}^{+}\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{K}^{+}$ decay process. The data sample was collected with the BABAR detector at the SLAC PEP-II asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider operating at center-of-mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately $230\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The spin of the $\ensuremath{\Xi}(1530)$ is established to be $3/2$. The existence of an $S$-wave amplitude in the ${\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ system is inferred, and its interference with the $\ensuremath{\Xi}(1530{)}^{0}$ amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected for the $\ensuremath{\Xi}(1530)$. The ${P}_{1}(\mathrm{cos}{\ensuremath{\theta}}_{{\ensuremath{\Xi}}^{\ensuremath{-}}})$ Legendre polynomial moment indicates the presence of a significant $S$-wave amplitude for ${\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ mass values above $1.6\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, and a dip in the mass distribution at approximately $1.7\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is interpreted as due to the coherent addition of a $\ensuremath{\Xi}(1690{)}^{0}$ contribution to this amplitude. This would imply ${J}^{P}=1/{2}^{\ensuremath{-}}$ for the $\ensuremath{\Xi}(1690)$. Attempts at fitting the $\ensuremath{\Xi}(1530{)}^{0}$ line shape yield unsatisfactory results, and this failure is attributed to interference effects associated with the amplitudes describing the ${K}^{+}{\ensuremath{\pi}}^{+}$ and/or ${\ensuremath{\Xi}}^{\ensuremath{-}}{K}^{+}$ systems.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 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".