S vs B

Hi Souad,

There is nothing wrong here. The weights must be included to account for the different signal and background cross sections.

Cheers,

Benjamin

Hi Benjamin,

Thanks a lot for your reply. I am afraid I have another question. The
number of events (nentries) kept after applying the cut of the signal is
higher than the number of events of the background, but the ratio in the
table is very suppressed, which might be explained by the difference in the
cross-section. but, why the chart doesn't show the number of events (or
the normalized events) kept after each cut?
Many thanks for your help to alleviate the confusion.

Best
Souad

Le mer. 5 janv. 2022 à 10:56, Benjamin Fuks <
<email address hidden>> a écrit :

> Your question #700094 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/700094
>
> Status: Open => Answered
>
> Benjamin Fuks proposed the following answer:
> Hi Souad,
>
> There is nothing wrong here. The weights must be included to account for
> the different signal and background cross sections.
>
> Cheers,
>
> Benjamin
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
>
> https://answers.launchpad.net/madanalysis5/+question/700094/+confirm?answer_id=0
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/madanalysis5/+question/700094
>
> You received this question notification because you asked the question.
>

--
Souad SEMLALI

Hi Souad,

We need to include cross section information to get a proper information on a number of events (for a given sample). The number of entries is indeed related to how many events you generated, which is not the information we want to see in a cutflow. For this reason, we show the *weighted* number of events passing each cut.

Cheers,

Benjamin

Hi Benjamin,

Thank you for your clarification! and apologies for dragging this for so
long. I understand now that the cut-flow chart shows the weighted number
of events after each cut.

I only have one last question. There is an example ( top-antitop, WW, ZZ
=signal with one leptonic and one invisible decay ) in one of the
tutorials
https://indico.cern.ch/event/568875/contributions/2397928/attachments/1459090/2253214/fuks_MC4BSM17.pdf,
slide =20

After applying the cut on MET < 125.0 GeV, the same table as the one in
the slide is produced (signal = 640). but the weighted events were
different (2.31x10^3)
"1_MET < 125.0" # 1st cut
9283 0 # nentries
2.316294e+03 0.000000e+00 # sum of weights
5.779617e+02 0.000000e+00 # sum of weights^2

Could you please clarify why the table doesn't show the number of the
weighted events, which is 2.31x10^3 instead of 640?

Thanks again for your help!

Best
Souad

Le jeu. 6 janv. 2022 à 21:35, Benjamin Fuks <
<email address hidden>> a écrit :

> Your question #700094 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/700094
>
> Status: Open => Answered
>
> Benjamin Fuks proposed the following answer:
> Hi Souad,
>
> We need to include cross section information to get a proper information
> on a number of events (for a given sample). The number of entries is
> indeed related to how many events you generated, which is not the
> information we want to see in a cutflow. For this reason, we show the
> *weighted* number of events passing each cut.
>
> Cheers,
>
> Benjamin
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
>
> https://answers.launchpad.net/madanalysis5/+question/700094/+confirm?answer_id=2
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/madanalysis5/+question/700094
>
> You received this question notification because you asked the question.
>

--
Souad SEMLALI

Thanks Jack Y. Araz, that solved my question.