differential cross section

Asked by Ayoub Hmissou on 2019-04-27

 Dear MadAnalysis team,

I need to plot a differential cross section .

Thanks a lot.
 Ayoub Hmissou

Question information

Language:
English Edit question
Status:
Answered
For:
MadAnalysis 5 Edit question
Assignee:
No assignee Edit question
Last query:
2019-04-30
Last reply:
2019-06-03
Benjamin Fuks (fuks) said : #1

Hi,

First of all, it is not necessary to leave a message here and to e-mail me as well. This will not make me answering faster, especially on Sunday… The short answer is: please tune the luminosity and the bin size accordingly and you will get your differential cross section.

Regards,

Benjamin

PS: Note that this question has already been asked several times on launchpad.

> On 27 Apr 2019, at 17:57 , Ayoub Hmissou <email address hidden> wrote:
>
> New question #680493 on MadAnalysis 5:
> https://answers.launchpad.net/madanalysis5/+question/680493
>
> Dear MadAnalysis team,
>
> I need to plot a differential cross section .
>
> Thanks a lot.
> Ayoub Hmissou
>
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

Ayoub Hmissou (ayb+) said : #2

Dear Benjamin,
thank you
I wrote this script , Did not ploting the differential cross section in axe-y

import /home/ayoub/Desktop/MG5_aMC_v2_6_5/bin/pp_ttb_wwbb/bin/internal/ufomodel
import /home/ayoub/Desktop/MG5_aMC_v2_6_5/bin/pp_ttb_wwbb/Events/run_01/unweighted_events.lhe.gz as un_evt
set un_evt.backcolor = green
set un_evt.linecolor = red
set main.graphic_render = root
#set main.stacking_method = normalize2one
set un_evt.xsection = 483.2
set main.lumi = 0.2
plot PT(b[1]) 40 0 500 #[logY]
submit /home/ayoub/Desktop/MG5_aMC_v2_6_5/bin/pp_ttb_wwbb/MA_AB

Benjamin Fuks (fuks) said : #3

Hi,

What do you mean? We do not really care about the title of the y-axis… You can always modify it at post-processing time.

However, you have here a bin size of 12.5 GeV, a luminosity of 0.2 fb-1. This won't give a normalization mapping the differential cross section.

Cheers,

Benjamin

> On 29 Apr 2019, at 01:12 , Ayoub Hmissou <email address hidden> wrote:
>
> Question #680493 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/680493
>
> Status: Answered => Open
>
> Ayoub Hmissou is still having a problem:
> Dear Benjamin,
> thank you
> I wrote this script , Did not ploting the differential cross section in axe-y
>
> import /home/ayoub/Desktop/MG5_aMC_v2_6_5/bin/pp_ttb_wwbb/bin/internal/ufomodel
> import /home/ayoub/Desktop/MG5_aMC_v2_6_5/bin/pp_ttb_wwbb/Events/run_01/unweighted_events.lhe.gz as un_evt
> set un_evt.backcolor = green
> set un_evt.linecolor = red
> set main.graphic_render = root
> #set main.stacking_method = normalize2one
> set un_evt.xsection = 483.2
> set main.lumi = 0.2
> plot PT(b[1]) 40 0 500 #[logY]
> submit /home/ayoub/Desktop/MG5_aMC_v2_6_5/bin/pp_ttb_wwbb/MA_AB
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

Ayoub Hmissou (ayb+) said : #4

Dear Benjamin,
thank you
 i generated p p > t t~, (t > w+ b) , ( t~ > w- b~ ) in Madgraph . and I would like to have a differential cross section dsigma/d PT(W) on the y-axis and PT on the x-axis

Benjamin Fuks (fuks) said : #5

Hi,

Please have a look to my previous answer. You need to tune the bin size and the luminosity accordingly so that you could get the proper normalization. It is as simple as that.

Cheers,

Benjamin

> On 29 Apr 2019, at 09:09 , Ayoub Hmissou <email address hidden> wrote:
>
> Question #680493 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/680493
>
> Status: Answered => Open
>
> Ayoub Hmissou is still having a problem:
> Dear Benjamin,
> thank you
> i generated p p > t t~, (t > w+ b) , ( t~ > w- b~ ) in Madgraph . and I would like to have a differential cross section dsigma/d PT(W) on the y-axis and PT on the x-axis
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

Ayoub Hmissou (ayb+) said : #6

Hi Benjamin ,
can you give me an exmeple for that , because i work on mode normal .

Benjamin Fuks (fuks) said : #7

Hi,

The cross section is given in pb, the luminosity in fb and the bin size is what you provide. Histograms should be normalized to the cross section times luminosity. Then you should account for the bin size. I am not sure to understand what you need more here.

Cheers,

Benjamin

> On 30 Apr 2019, at 10:04 , Ayoub Hmissou <email address hidden> wrote:
>
> Question #680493 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/680493
>
> Status: Answered => Open
>
> Ayoub Hmissou is still having a problem:
> Hi Benjamin ,
> can you give me an exmeple for that , because i work on mode normal .
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

Ayoub Hmissou (ayb+) said : #8

Hi Benjamin,
I genereted N=100000 events andi i have the cross section 483.2 pb , the luminosity is (L=N/sigma ) 0.206953 fb-1
and i write the script:

set un_evt.xsection = 483.2
set main.lumi = 0.206953
plot PT(w+[1]) 40 0 500 [logY]

sorry i dont unddrtsande how to tune the bin size and the luminosity accordingly.

Benjamin Fuks (fuks) said : #9

Hi,

When one creates a histogram, one internally fixes the units associated with each bin. One therefore needs to choose the luminosity and the number of bins so that these units map pb/GeV.

Cheers,

Benjamin

> On 3 Jun 2019, at 24:03 , Ayoub Hmissou <email address hidden> wrote:
>
> Question #680493 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/680493
>
> Ayoub Hmissou posted a new comment:
> Hi Benjamin,
> I genereted N=100000 events andi i have the cross section 483.2 pb , the luminosity is (L=N/sigma ) 0.206953 fb-1
> and i write the script:
>
> set un_evt.xsection = 483.2
> set main.lumi = 0.206953
> plot PT(w+[1]) 40 0 500 [logY]
>
> sorry i dont unddrtsande how to tune the bin size and the luminosity accordingly.
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

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