Measurement of the Λ<sub><i>b</i></sub><sup>0</sup> Lifetime in the Decay Λ<sub><i>b</i></sub><sup>0</sup> → <i>J</i>/ψΛ<sup>0</sup> with the D0 Detector
Bibliographic record
Abstract
We present measurements of the Λb0 lifetime in the exclusive decay channel Λb0 → J/ψΛ0, with J/ψ → μ+μ- and Λ0 → pπ-, the B0 lifetime in the decay Λ0 → J/ψKs0 with J/ψ → μ+μ- and Ks0 → π+π-, and the ratio of these lifetimes. The analysis is based on approximately 250 pb-1 of data recorded with the D0 detector in pp̅ collisions at √s = 1.96 TeV. The Λb0 lifetime is determined to be τ(Λb0) = 1.22-0.18+0.22(stat) ± 0.04(syst) ps, the B0 lifetime τ(B0) = 1.40-0.10+0.11(stat) ± 0.03(syst) ps, and the ratio τ(Λb0)/τ(B0) = 0.87-0.14+0.17 (stat) ± 0.03(syst). In contrast with previous measurements using semileptonic decays, this is the first determination of the Λb0 lifetime based on a fully reconstructed decay channel.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.004 | 0.001 |
| Research integrity | 0.001 | 0.004 |
| Insufficient payload (model declined to judge) | 0.001 | 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; 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".