The chart tracks selected signal yield and approximate significance versus integrated luminosity using the current parameter set.
| Scenario | Energy (TeV) | Luminosity (fb-1) | Cross section (pb) | Branching ratio (%) | Efficiency (%) | Expected selected events |
|---|---|---|---|---|---|---|
| tt̄ dilepton selection | 13.0 | 36 | 832 | 4.67 | 62 | 867,230 |
| tt̄ lepton+jets selection | 13.6 | 150 | 845 | 29.2 | 38 | 14,064,180 |
| Single top t-channel | 13.0 | 100 | 238 | 10.8 | 41 | 1,053,864 |
| Single top tW study | 13.0 | 140 | 63.1 | 4.67 | 55 | 226,901 |
These rows are illustrative calculator examples, not fixed detector recommendations.
σprod = σref × (E / Eref)n × K
σsel = σprod × BR × ε
Nsig = σsel × L × 1000
σinf = (Nobs − B) / (L × BR × ε × 1000)
Z ≈ S / √(S + B)
Here, E is collision energy in TeV, K is the correction factor, BR is branching ratio, ε is acceptance × efficiency, L is integrated luminosity in fb-1, S is signal, and B is background. The factor 1000 converts pb × fb-1 into event counts.
- Select the top production process that best matches your study.
- Choose direct cross-section mode or reference-energy scaling mode.
- Enter collision energy, luminosity, branching ratio, and detector efficiency.
- Add observed and background counts if you want an inferred cross section.
- Enter uncertainty percentages to estimate propagated output uncertainty.
- Press Calculate Production to show results above the form.
- Use the graph to compare yield and significance across luminosity values.
- Export the current result block with the CSV or PDF buttons.
1) What does this calculator estimate?
It estimates top-quark production yields, selected signal counts, inferred cross sections from observed data, and approximate significance after branching and efficiency effects.
2) Why is branching ratio included?
Only a fraction of produced top events enter a chosen final state. The branching ratio converts inclusive production into the decay channel you actually analyze.
3) Why is efficiency separate from branching ratio?
Branching ratio describes physics decays. Efficiency captures detector acceptance, trigger response, reconstruction, and analysis cuts. Keeping them separate makes studies more transparent.
4) When should I use scaling mode?
Use scaling mode for quick scenario studies between collider energies when you have a trusted reference cross section and want a simple extrapolation.
5) Is the scaling law exact?
No. It is a practical approximation for planning and teaching. Precision results should come from dedicated theory tools, generator studies, or collaboration-approved predictions.
6) What does the K-factor do?
The K-factor rescales the baseline cross section to approximate higher-order corrections or another normalization choice in your workflow.
7) How is significance computed here?
The page uses the common approximation Z ≈ S divided by the square root of S plus B. It is helpful for quick comparisons, not a full likelihood analysis.
8) Can I use this for single-top channels?
Yes. The process selector includes common single-top modes, and the calculator works as long as you enter cross sections and decay assumptions consistent with your study.