alphaT in expert mode of Ma5 is always becoming zero

Asked by Abhaya Kumar Swain on 2018-04-10

Dear Ma5 team,

I am calculating alphaT in expert mode for some parton level events and each event has multiple visible particles in the final state. The alphaT is defined as follows,

const MCEventFormat* kthevent = event.mc();

double alphaT = PHYSICS->Transverse->AlphaT(kthevent);

When I run the code it compiles successfully but the alphaT is becoming zero. I expected it to be non-zero. Is this definition for alphaT is correct? Do I need to change something in alphaT for a multijet event?

Thanks in advance
Abhaya

Question information

Language:
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Status:
Answered
For:
MadAnalysis 5 Edit question
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Last query:
2018-04-11
Last reply:
2018-04-12
Benjamin Fuks (fuks) said : #1

Dear Abhaya,

How should I know? I don't know what you coded, what you generated, etc… In principle, the alpha_T implementation had been validated. Can you try in the normal mode?

Regards,

Benjamin

> On 10 Apr 2018, at 05:22 , Abhaya Kumar Swain <email address hidden> wrote:
>
> New question #667799 on MadAnalysis 5:
> https://answers.launchpad.net/madanalysis5/+question/667799
>
> Dear Ma5 team,
>
> I am calculating alphaT in expert mode for some parton level events and each event has multiple visible particles in the final state. The alphaT is defined as follows,
>
> const MCEventFormat* kthevent = event.mc();
>
> double alphaT = PHYSICS->Transverse->AlphaT(kthevent);
>
> When I run the code it compiles successfully but the alphaT is becoming zero. I expected it to be non-zero. Is this definition for alphaT is correct? Do I need to change something in alphaT for a multijet event?
>
>
> Thanks in advance
> Abhaya
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.
>

Hi Benjamin,

Thanks for your prompt reply. Sorry, I asked a wrong question. The way I am calling alphaT inside my code is,

const MCEventFormat* kthevent = event.mc();

double alphaT = PHYSICS->Transverse->AlphaT(kthevent);

So what I meant was whether this is the way one should call alphaT or something is missing here. Obviously something is wrong here otherwise I would not have got zero always but I am not able to figure it out.

 As you mentioned, I checked in normal mode and there also it is becoming zero always. I am using a ttbar sample at the parton level, where both the top and anti-top are decaying hadronically.

Thanks and regards
Abhaya

Benjamin Fuks (fuks) said : #3

Hi,

I don't know what is wrong as I have no idea about what your events look like. You can check the AlphaT code here:
  tools/SampleAnalyzer/Commons/Service/TransverseVariables.cpp
I suggest to add print statements here and there in the code to understand what is going on.

Best regards,

Benjamin

> On 11 Apr 2018, at 08:47 , Abhaya Kumar Swain <email address hidden> wrote:
>
> Question #667799 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/667799
>
> Status: Answered => Open
>
> Abhaya Kumar Swain is still having a problem:
> Hi Benjamin,
>
> Thanks for your prompt reply. Sorry, I asked a wrong question. The way
> I am calling alphaT inside my code is,
>
> const MCEventFormat* kthevent = event.mc();
>
> double alphaT = PHYSICS->Transverse->AlphaT(kthevent);
>
> So what I meant was whether this is the way one should call alphaT or
> something is missing here. Obviously something is wrong here otherwise I
> would not have got zero always but I am not able to figure it out.
>
> As you mentioned, I checked in normal mode and there also it is
> becoming zero always. I am using a ttbar sample at the parton level,
> where both the top and anti-top are decaying hadronically.
>
>
> Thanks and regards
> Abhaya
>
> --
> You received this question notification because you are an answer
> contact for MadAnalysis 5.
>

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