ROOSTAT question


I have question about using roostat

now I have simple data like this


100 4e+06 1.13e+04
1000 7e+05 1.34e+03
2000 1e+05 299
3000 40000 90.6
4000 10000 37.3
5000 5000 10.7

actually, this data is consist of “mass” “cross section” "error"
so I want to draw mass dependent cross section plot with CLs .(x axis:mass, y axis:cross section).

I confused to use roostat.

simple case, I just can draw plot(graph).

but I can not calculate confidence level limit or 1 sigma(2sigma).

help me



I am not sure what exactly you want to do. You have some measurements of cross-sections vs mass with its uncertainties.
CLs is a procedure to find the 95% (or lower confidence value) limit for the cross-section. It make sense to quit a limit when you measure cross-section values consistent with zero. If you have measurements which are significative different than zero, as in your case, you should not plot the limit value but just the measurements and its uncertainties.
You can just use a TGraphError to make that plot

RooStats helps you to find confidence interval values of your cross-section (or limits in case they are close to zero). The confidence intervals are computed from a model description of your experiment. This consists for example from your observed data, the expectations for the single and for the background.

Best Regards