how to plot lepton distribution with hepmc

Asked by HuanyuBi on 2019-01-22

Hi,
I generate p p > w- w+ h [QCD].
I use madspin to decay w- > l- vl~; w+ > l+ vl (l=e,mu); h> b b~ and use pythia8 to do the parton shower.
I set mu,ta,b stable in the shower_card.dat (tap_stable = T ; tam_stable = T; mup_stable = T ; mum_stable = T ).
Then I get the events.hepmc, the question is how to plot the pt(l-), pt(b) or pt_missing correctly.
I have tried three methods to get these plots

First, I use command ma5
>set main.mode = parton
>import events.hepmc
>plot PT(l-[1])
>plot PT(b[1])
>plot MET
>submit
Then I get the plots of PT(l-[1]) and MET, but the PT(b[1]) is empty. I think it is because I do not use fastjet to reconstruct b-jet.

Second, I use command ma5 -R
>ma5>define invisible = 12 14 16 -12 -14 -16
>ma5>set main.fastsim.package = fastjet
>ma5>set main.fastsim.algorithm = antikt
>ma5>set main.fastsim.radius = 0.4
>ma5>set main.fastsim.ptmin = 0.0
>ma5>set main.fastsim.bjet_id.matching_dr = 0.4
>ma5>set main.fastsim.bjet_id.efficiency = 1.0
>ma5>set main.fastsim.bjet_id.misid_cjet = 0.0
>ma5>set main.fastsim.bjet_id.misid_ljet = 0.0
>ma5>set main.fastsim.tau_id.efficiency = 1.0
>ma5>set main.fastsim.tau_id.misid_ljet = 0.0
>import events.hepmc
>plot PT(l-[1])
>plot PT(b[1])
>plot MET
>set main.outputfile=reconstruct.lhe
>submit
Then I get these three plots, besides, I find PT(l-[1]) and MET are same with the first method.

Third, I use reconstruct.lhe which is produced by the second method. I use command ma5
>set main.mode = parton
>import reconstruct.lhe
>plot PT(l-[1])
>plot PT(b[1])
>plot MET
>set main.stacking_method = normalize2one
>submit
It is strange that I have to use “set main.stacking_method = normalize2one” or I get empty plots. Besides, I find that PT(l-[1]) and PT(b[1]) are same with these plots in the second method except they are normalized to one. I also find the MET in the third method is not same with MET in the second method( even I ignore care about the normalization factor).

So, which one is correct. If these three methods are all wrong, how to get the correct plots from .hepmc. Thank you very much!

Huanyu Bi

Question information

Language:
English Edit question
Status:
Answered
For:
MadAnalysis 5 Edit question
Assignee:
No assignee Edit question
Last query:
2019-01-24
Last reply:
2019-01-25
Benjamin Fuks (fuks) said : #1

Hi Huanyu,

> First, I use command ma5
>> set main.mode = parton
>> import events.hepmc
>> plot PT(l-[1])
>> plot PT(b[1])
>> plot MET
>> submit
> Then I get the plots of PT(l-[1]) and MET, but the PT(b[1]) is empty. I think it is because I do not use fastjet to reconstruct b-jet.
This is normal as there is no final-state b-quark in an hepmc file (after pythia).

> Second, I use command ma5 -R
>> ma5>define invisible = 12 14 16 -12 -14 -16
>> ma5>set main.fastsim.package = fastjet
>> ma5>set main.fastsim.algorithm = antikt
>> ma5>set main.fastsim.radius = 0.4
>> ma5>set main.fastsim.ptmin = 0.0
>> ma5>set main.fastsim.bjet_id.matching_dr = 0.4
>> ma5>set main.fastsim.bjet_id.efficiency = 1.0
>> ma5>set main.fastsim.bjet_id.misid_cjet = 0.0
>> ma5>set main.fastsim.bjet_id.misid_ljet = 0.0
>> ma5>set main.fastsim.tau_id.efficiency = 1.0
>> ma5>set main.fastsim.tau_id.misid_ljet = 0.0
>> import events.hepmc
>> plot PT(l-[1])
>> plot PT(b[1])
>> plot MET
>> set main.outputfile=reconstruct.lhe
>> submit
> Then I get these three plots, besides, I find PT(l-[1]) and MET are same with the first method.
That sounds good.

> Third, I use reconstruct.lhe which is produced by the second method. I use command ma5
>> set main.mode = parton
>> import reconstruct.lhe
>> plot PT(l-[1])
>> plot PT(b[1])
>> plot MET
>> set main.stacking_method = normalize2one
>> submit
> It is strange that I have to use “set main.stacking_method = normalize2one” or I get empty plots. Besides, I find that PT(l-[1]) and PT(b[1]) are same with these plots in the second method except they are normalized to one. I also find the MET in the third method is not same with MET in the second method( even I ignore care about the normalization factor).
This is not strange as the cross section is lost when you analyse a reconstructed event file. Setting the xsection by hand solves the issue (or giving up a cross-section-based normalization). The methods 2 and 3 should give the same results are the plots are generated from the same events… Ar you sure this is not an artefact of the nornmalization?

Cheers,

Benjamin

HuanyuBi (bihuanyu) said : #2

I am sure that I used the same events.
The MET in method 2 looks like

 | - -
 | - -
 |- -
 | -
 | -
 | -
 |
 |
 |-------------------------------------------------->

However the MET in method 3 looks like
 |-
 |
 |
 | - -
 | - -
 | -
 | -
 |
 |-------------------------------------------------->

That is, in method 3, it seems that too many events are in the first bin. I find that MET in method 3 almost comes form MET~0.

HuanyuBi (bihuanyu) said : #3

Hi

Sorry, I don't know why the plots I typed in the input box are not same with the above display, it seems that the "Blank space" is not displayed. I mean that in method 3, MET have an very high peak at the first bin and a very low peak at the fifth bin. Besides, MET in method 2 have only one peak at the fifth bin.
Thank you very much

Huanyu bi

Benjamin Fuks (fuks) said : #4

Hi,

This first bin seems spurious to me. Can you please try with 10-15 events, and share the files (LHE, hepmc and reco-lhc)?

Cheers,

Benjamin

> On 24 Jan 2019, at 04:32 , HuanyuBi <email address hidden> wrote:
>
> Question #678000 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/678000
>
> Status: Answered => Open
>
> HuanyuBi is still having a problem:
> I am sure that I used the same events.
> The MET in method 2 looks like
>
> | - -
> | - -
> |- -
> | -
> | -
> | -
> |
> |
> |-------------------------------------------------->
>
> However the MET in method 3 looks like
> |-
> |
> |
> | - -
> | - -
> | -
> | -
> |
> |-------------------------------------------------->
>
> That is, in method 3, it seems that too many events are in the first
> bin. I find that MET in method 3 almost comes form MET~0.
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.

HuanyuBi (bihuanyu) said : #5

Hi,

The attachment includes the LHE, hepmc and reco-lhe event files. Another strange thing is that when I plot MET with this 15 events LHE file, I also find that there is very high peak in the first bin(~1 GeV), however, when I try to generate 100k events, this peak disappears. I use ma5_1.6.

I have another question, that is how to plot the PT(b) (for example uu ~> w-w+h[QCD], H>bb) which the b is comes form the H >bb rather than parton shower. Because if I just simply plot PT(b[1]) in -R mode, there must be some b-jets which are from parton shower. If I use the option, select 115<M(b[1] b[2])<135, I find that the cross section becomes smaller, and I think this is because some events are dropped in this constraint. So how to plot the b-jets distribution which are come from higgs decay.

Thank you very much!

Huanyu Bi

> -----Original Messages-----
> From: "Benjamin Fuks" <email address hidden>
> Sent Time: 2019-01-24 15:38:36 (Thursday)
> To: <email address hidden>
> Cc:
> Subject: Re: [Question #678000]: how to plot lepton distribution with hepmc
>
> Your question #678000 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/678000
>
> Status: Open => Answered
>
> Benjamin Fuks proposed the following answer:
> Hi,
>
> This first bin seems spurious to me. Can you please try with 10-15
> events, and share the files (LHE, hepmc and reco-lhc)?
>
> Cheers,
>
> Benjamin
>
> > On 24 Jan 2019, at 04:32 , HuanyuBi <email address hidden> wrote:
> >
> > Question #678000 on MadAnalysis 5 changed:
> > https://answers.launchpad.net/madanalysis5/+question/678000
> >
> > Status: Answered => Open
> >
> > HuanyuBi is still having a problem:
> > I am sure that I used the same events.
> > The MET in method 2 looks like
> >
> > | - -
> > | - -
> > |- -
> > | -
> > | -
> > | -
> > |
> > |
> > |-------------------------------------------------->
> >
> > However the MET in method 3 looks like
> > |-
> > |
> > |
> > | - -
> > | - -
> > | -
> > | -
> > |
> > |-------------------------------------------------->
> >
> > That is, in method 3, it seems that too many events are in the first
> > bin. I find that MET in method 3 almost comes form MET~0.
> >
> > --
> > You received this question notification because you are an answer
> > contact for MadAnalysis 5.
>
> --
> 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/678000/+confirm?answer_id=3
>
> 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/678000
>
> You received this question notification because you asked the question.

Benjamin Fuks (fuks) said : #6

Hi Huanyu,

> The attachment includes the LHE, hepmc and reco-lhe event files. Another
> strange thing is that when I plot MET with this 15 events LHE file, I
> also find that there is very high peak in the first bin(~1 GeV),
> however, when I try to generate 100k events, this peak disappears. I use
> ma5_1.6.
There is no attachment. But please try with v1.7 first. It should be deployed very soon. What you can do is to check the LH file with your eyes and check "manually" the value of the missing energy. This would allow to double check your plot.

>
> I have another question, that is how to plot the PT(b) (for example uu
> ~> w-w+h[QCD], H>bb) which the b is comes form the H >bb rather than
> parton shower. Because if I just simply plot PT(b[1]) in -R mode, there
> must be some b-jets which are from parton shower. If I use the option,
> select 115<M(b[1] b[2])<135, I find that the cross section becomes
> smaller, and I think this is because some events are dropped in this
> constraint. So how to plot the b-jets distribution which are come from
> higgs decay.
At the reco level, this is impossible to do. You don't have this information anymore. At the hard scattering level (after madpsin), you can enforce the b to originate from a higgs boson with the '<' symbol.

Cheers,

Benjamin

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