Observation of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>Ω</mml:mi><mml:mi>b</mml:mi><mml:mo>−</mml:mo></mml:msubsup></mml:math>baryon and measurement of the properties of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>Ξ</mml:mi><mml:mi>b</mml:mi><mml:mo>−</mml:mo></mml:msubsup></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>Ω</mml:mi><mml:mi>b</mml:mi><mml:mo>−</mml:mo></mml:msubsup></mml:math>baryons
Bibliographic record
Abstract
We report the observation of the bottom, doubly-strange baryon ${\ensuremath{\Omega}}_{b}^{\ensuremath{-}}$ through the decay chain ${\ensuremath{\Omega}}_{b}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\Omega}}^{\ensuremath{-}}$, where $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, ${\ensuremath{\Omega}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\Lambda}{K}^{\ensuremath{-}}$, and $\ensuremath{\Lambda}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}$, using $4.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data from $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, and recorded with the Collider Detector at Fermilab. A signal is observed whose probability of arising from a background fluctuation is $4.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$, or 5.5 Gaussian standard deviations. The ${\ensuremath{\Omega}}_{b}^{\ensuremath{-}}$ mass is measured to be $6054.4\ifmmode\pm\else\textpm\fi{}6.8(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$. The lifetime of the ${\ensuremath{\Omega}}_{b}^{\ensuremath{-}}$ baryon is measured to be ${1.13}_{\ensuremath{-}0.40}^{+0.53}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.02(\mathrm{syst})\text{ }\text{ }\mathrm{ps}$. In addition, for the ${\ensuremath{\Xi}}_{b}^{\ensuremath{-}}$ baryon we measure a mass of $5790.9\ifmmode\pm\else\textpm\fi{}2.6(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.8(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and a lifetime of ${1.56}_{\ensuremath{-}0.25}^{+0.27}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.02(\mathrm{syst})\text{ }\text{ }\mathrm{ps}$. Under the assumption that the ${\ensuremath{\Xi}}_{b}^{\ensuremath{-}}$ and ${\ensuremath{\Omega}}_{b}^{\ensuremath{-}}$ are produced with similar kinematic distributions to the ${\ensuremath{\Lambda}}_{b}^{0}$ baryon, we find $\frac{\ensuremath{\sigma}({\ensuremath{\Xi}}_{b}^{\ensuremath{-}})\mathcal{B}({\ensuremath{\Xi}}_{b}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\Xi}}^{\ensuremath{-}})}{\ensuremath{\sigma}({\ensuremath{\Lambda}}_{b}^{0})\mathcal{B}({\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\Lambda})}={0.167}_{\ensuremath{-}0.025}^{+0.037}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.012(\mathrm{syst})$ and $\frac{\ensuremath{\sigma}({\ensuremath{\Omega}}_{b}^{\ensuremath{-}})\mathcal{B}({\ensuremath{\Omega}}_{b}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\Omega}}^{\ensuremath{-}})}{\ensuremath{\sigma}({\ensuremath{\Lambda}}_{b}^{0})\mathcal{B}({\ensuremath{\Lambda}}_{b}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\Lambda})}={0.045}_{\ensuremath{-}0.012}^{+0.017}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.004(\mathrm{syst})$ for baryons produced with transverse momentum in the range of $6--20\text{ }\text{ }\mathrm{GeV}/c$.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.049 | 0.021 |
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".