Observation of Single Top-Quark Production and Measurement of |<em>V<sub>tb</sub></em>| with CDF
Bibliographic record
Abstract
Top quarks are most often produced in pairs via gluons, the carriers of the strong force. Such pairs were first observed at Fermilab in 1995. But single top quarks can also be produced via an electroweak process involving a W boson and a bottom quark. This process is sensitive to the top-bottom quark mixing parameter known as Vtb and the rate at which it occurs provides new information about the top and bottom quarks. (The top and bottom quarks form a third generation of quarks, added to the first generation, up and down quarks, and the second generation, charm and strange quarks.) Measurements of single top quark production can therefore constrain extensions of the standard model, such as those with a fourth generation of quarks. Single top quark events are more difficult than top quark pair events to pick out of the vast number of background events. The first evidence for single top quark production was reported only recently by the Fermilab experiments, in 2006 for the D0 experiment and 2008 for the CDF experiment, with a statistical significance of 3.4 and 3.7 standard deviations, respectively. Since that time, both D0 and CDF have taken more data and improved their multivariate analyses. In a pair of papers appearing in Physical Review Letters, they now claim to have definitively observed single top quark production, each at the 5.0 standard deviation level. They also put constraints on Vtb, which agree with what the standard model predicts.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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".