Time-dependent angular analysis of the decay B<sup>0</sup><sub>s</sub>→ J/ψφ and extraction of ΔΓ<sub>s</sub> and the CP-violating weak phase φ<sub>s</sub> by ATLAS
Bibliographic record
Abstract
A measurement of B<sup>0</sup><sub>s</sub> → J/ψϕ decay parameters, including the CP-violating weak phase ϕ<sub>s</sub> and the decay width difference ΔΓ<sub>s</sub> is reported, using 4.9 fb<sub>−1</sub> of integrated luminosity collected in 2011 by the ATLAS detector from LHC pp collisions at a centre-of-mass energy √s = 7 TeV. The mean decay width Γ<sub>s</sub> and the transversity amplitudes |A<sub>0</sub>(0)|<sup>2</sup> and |A<sub>∥</sub>(0)|<sup>2</sup> are also measured. The values reported for these parameters are: ϕ<sub>s</sub> = 0.22 ± 0.41 (stat.) ± 0.10 (syst.) rad ΔΓ<sub>s</sub> = 0.053 ± 0.021 (stat.) ± 0.010 (syst.) ps<sup>−1</sup> Γ<sub>s</sub> = 0.677 ± 0.007 (stat.) ± 0.004 (syst.) ps<sup>−1</sup> |A<sub>0</sub>(0)|<sup>2</sup> = 0.528 ± 0.006 (stat.) ± 0.009 (syst.) |A<sub>∥</sub>(0)|<sup>2</sup> = 0.220 ± 0.008 (stat.) ± 0.007 (syst.) where the values quoted for ϕ<sub>s</sub> and ΔΓ<sub>s</sub> correspond to the solution compatible with the external measurements to which the strong phase δ⊥ is constrained and where ΔΓ<sub>s</sub> is constrained to be positive. The fraction of S-wave KK or f<sub>0</sub> contamination through the decays Bsup>0</sup><sub>s</sub> → J/ψK+K− (f<sub>0</sub>) is measured as well and is found to be consistent with zero. Results for ϕ<sub>s</sub> and ΔΓ<sub>s</sub> are also presented as 68%, 90% and 95% likelihood contours, which show agreement with Standard Model expectations.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".