Perturbative corrections to the determination of Vub from the P+ spectrum in B -> Xu l nu bar
Bibliographic record
Abstract
We investigate the relation between the E spectrum in B {yields} X{sub s}{gamma} decay and the P{sub +} spectrum in semileptonic B {yields} X{sub u}{ell}{bar {nu}} decay (P{sub +} is the hadronic energy minus the absolute value of the hadronic three-momentum), which provides in principle the theoretically simplest determination of |V{sub ub}| from any of the ''shape function regions'' of B {yields} X{sub u}{ell}{bar {nu}} spectra. We calculate analytically the P{sub +} spectrum to order {alpha}{sub s}{sup 2}{beta}{sub 0}, and study its relation to the B {yields} X{sub s}{gamma} photon spectrum to eliminate the leading dependence on nonperturbative effects. We compare the result of fixed order perturbation theory to the next-to-leading log renormalization group improved calculation, and argue that fixed order perturbation theory is likely to be a more appropriate expansion. Implications for the perturbative uncertainties in the determination of |V{sub ub}| from the P{sub +} spectrum are discussed.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".