Measurement of the moments of the hadronic invariant mass distribution in semileptonic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math>decays
Bibliographic record
Abstract
Using 180 $\mathrm{p}{\mathrm{b}}^{\ensuremath{-}1}$ of data collected with the CDF II detector at the Tevatron, we measure the first two moments of the hadronic invariant mass-squared distribution in charmed semileptonic $B$ decays. From these we determine the nonperturbative Heavy Quark Effective Theory parameters $\ensuremath{\Lambda}$ and ${\ensuremath{\lambda}}_{1}$ used to relate the $B$ meson semileptonic branching ratio to the CKM matrix element $|{V}_{cb}|$. For a minimum lepton momentum of 0.7 GeV/$c$ in the $B$ rest frame we measure the first two moments of the ${D}^{**}\ensuremath{\rightarrow}{D}^{(*)}\ensuremath{\pi}$ component to be $⟨{m}_{{D}^{**}}^{2}⟩=(5.83\ifmmode\pm\else\textpm\fi{}{0.16}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.08}_{\mathrm{syst}})\text{ }\text{ }{\mathrm{GeV}}^{2}/{c}^{4}$ and $⟨({m}_{{D}^{**}}^{2}\ensuremath{-}⟨{m}_{{D}^{**}}^{2}⟩{)}^{2}⟩=(1.30\ifmmode\pm\else\textpm\fi{}{0.69}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.22}_{\mathrm{syst}})\text{ }\text{ }\mathrm{Ge}{\mathrm{V}}^{4}/{c}^{8}$. Combining these with the discrete mass terms from the $D$ and ${D}^{*}$ mesons, we find the total moments to be $⟨{M}_{{X}_{c}}^{2}⟩\ensuremath{-}{\overline{m}}_{D}^{2}=(0.467\ifmmode\pm\else\textpm\fi{}{0.038}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.068}_{\mathrm{syst}})\text{ }\text{ }\mathrm{Ge}{\mathrm{V}}^{2}/{c}^{4}$ and $⟨({M}_{{X}_{c}}^{2}\ensuremath{-}⟨{M}_{{X}_{c}}^{2}⟩{)}^{2}⟩=(1.05\ifmmode\pm\else\textpm\fi{}{0.26}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.13}_{\mathrm{syst}})\text{ }\text{ }\mathrm{Ge}{\mathrm{V}}^{4}/{c}^{8}$, where ${\overline{m}}_{D}$ is the spin-averaged $D$ mass. The systematic error is dominated by the uncertainties in the world-average branching ratios used to combine the $D$, ${D}^{*}$, and ${D}^{**}$ contributions. The analysis makes no assumptions about the shape or resonant structure of the ${D}^{**}\ensuremath{\rightarrow}{D}^{(*)}\ensuremath{\pi}$ invariant mass distribution.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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 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".