differential cross section

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.

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

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.

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

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.

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

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.

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.

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.

Hi Benjamin,

please for this example how to tune the bin size and the luminosity .thank you

N=100000
set un_evt.xsection = 483.2
set main.lumi = 0.2
plot PT(b[1]) 40 0 500 #[logY]

Hello,

You are already doing it in your example (40 bins from 0 to 500 GeV; luminosity of 0.2 fb-1). I am afraid I hence do not understand what you exactly want.

Regards,

Benjamin

> On 28 Aug 2019, at 02:32 , 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,
>
> please for this example how to tune the bin size and the luminosity .thank you
>
> N=100000
> set un_evt.xsection = 483.2
> set main.lumi = 0.2
> plot PT(b[1]) 40 0 500 #[logY]
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

hello,

I would like to have a differential cross section dsigma and PT on the x-axis .

for this example :
N=100000
set un_evt.xsection = 483.2
set main.lumi = 0.2 ( L=N/sigma 100000/483200 =0.2)
plot PT(b[1]) 40 0 500 #[logY]

and i have a root file selection_0.C :
 I added this
 S0_PT_0->Scale(1./0.206953); // With this you scale each bin with the inverse of the integrated luminosity (1/L) so you have now only sigma in each bin .
so Is this true ?

Hi,

It is sufficient to setup the bin size and the luminosity so that the histogram matches the differential distribution normalisation. There is nothing complicated oer tricky here.

Best regards,

Benjamin

> On 29 Aug 2019, at 11:17 , 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:
> hello,
>
> I would like to have a differential cross section dsigma and PT on
> the x-axis .
>
> for this example :
> N=100000
> set un_evt.xsection = 483.2
> set main.lumi = 0.2 ( L=N/sigma 100000/483200 =0.2)
> plot PT(b[1]) 40 0 500 #[logY]
>
> and i have a root file selection_0.C :
> I added this
> S0_PT_0->Scale(1./0.206953); // With this you scale each bin with the inverse of the integrated luminosity (1/L) so you have now only sigma in each bin .
> so Is this true ?

Hi Benjamin,

please for this example

N=100000
set un_evt.xsection = 483.2
set main.lumi = 0.2
plot PT(b[1]) 40 0 500 #[logY]

what the bin size give a normalization mapping the differential cross section.

Hi Ayoub,

I don't follow you. You require a histogram of 40 bins between 0 and 500 GeV. The bin size is thus 12.5 GeV. The y-axis will be normalised in events per bin (i.e. per 12.5 GeV) for 200/pb. You only need to multiply/divide those numbers with the total rate to get the normalisation.

Cheers,

Benjamin

Hi Benjamin,
Thank you so much for your answer! let me see if I got it

N=100000
set un_evt.xsection = 483.2
set main.lumi =( 1/1000)*12.5
plot PT(b[1]) 40 0 500 [logY]
To obtain the differential cross section in y-axis in units of pb/GeV
right?

Hi,

Yes this should work.

Cheers,

Benjamin