Bibliographic record
Abstract
Using a data sample of integrated luminosity ∫ Ldt = 28.9 +/- 1.2 pb-1 of proton-antiproton collisions at a center-of-mass energy s = 1.8 TeV collected with the CDF detector at the Fermilab Tevatron collider, we searched for "penguin" radiative decays of B0d and B0s mesons which involve the flavor-changing neutral-current transition of a b quark into an s quark with the emission of a photon, b→sg . Specifically, we searched for the decays B0d→K*0g, K*0→K+p- and B0s→fg, f→K+K- , as well as for the charge conjugate chains. In order to collect such decays, we designed a specialized trigger which required information on all the decay products of the B meson decay chain, the first such trigger in a hadron collider environment. This "penguin" trigger collected data during the last quarter of the 1994--1996 data taking period. After all selection criteria, we are left with one candidate B0d→K*0g decay and no B0s→fg candidates in the entire data sample. We then proceed to set upper limits on the branching fractions of the penguin channels. We exploit the topological similarity between the B¯→e-D0 X,D0→K-p + and the penguin decays, by forming ratios of branching fractions between the penguin and the B¯→e-D0 X channels. Uncertainties associated with the B meson production cross section, common efficiency corrections and other systematic effects are minimal in the ratio of branching fractions. The uncertainty on the B¯→e-D0 X yield is the biggest contribution to the total uncertainty on the penguin branching fraction. We assume equal production rates for B+u and B0d mesons, while the probability of producing B0s mesons relative to B0d mesons, fs/fd, is taken to be 1/3. The inferred upper limits on the ratios of branching fractions are B(B0 s→fg)B( B¯→e-D0 X)<3.5x10-3 at90% C.L. B(B 0d→K*0g) B(B¯→e- D0X)<1.9x10-3 at90%C.L. Relative branching fraction measurements were combined with the branching fraction measurement of the B¯→e-D0 X,D0→K-p + decay chain, B(B¯→e- D0X)xB(D0→ K-p+) = (294 +/- 40) x 10-5, to extract the following absolute branching fraction limits B(B0s→ fg)<2.8x10-4 at90%C.L. B(B0d →K*0g)<1.5x10-4 at90% C.L. The upper limit for the B0d→K*0g decay is consistent with the branching fraction measurement reported by the CLEO collaboration, B(B0d→K*0 g) = (4.0 +/- 1.9) x 10-5, while the upper limit for the as yet unobserved B0s→fg decay is the most constraining one set to date.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 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".