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[FIXED] Problem with daughter links [message #14800]

Fri, 24 May 2013 17:04

Andreas Pitka
Messages: 38
Registered: November 2011
Location: Gießen

continuous participant

From: *physik.uni-giessen.de

Dear all,

i realized following weird problem, when examining the decay: anti-D0 -> K+ pi-

I got my RhoCandList by aD.Combine(Kp,pim)

when i now compare the values:


for(int j=0;j<aD.GetLength();j++)
{
// Mass of the anti-D0 Candidate
double mass=aD[j].M();

TLorentzVector d1_p4=aD[j].Daughter(0)->P4();   
TLorentzVector d2_p4=aD[j].Daughter(1)->P4(); 
TLorentzVector moth_p4=d1_p4+d2_p4;

// Mass of the anti-D0 by the four-vectors of the two daughters
double mass2=moth_p4.Mag();
}

they are quite often not the same. How can this be?

Best regards

Andreas

ps i used rev 19948

[Updated on: Thu, 04 July 2013 14:12] by Moderator

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Re: Problem with daughter links [message #14803 is a reply to message #14800]

Sat, 25 May 2013 12:02

StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino

first-grade participant

From: 2.235.190*

Why don't you prepare a simple set of sim digi reco pid dec and an analysis macro, so that it is possible to reproduce all your problems?

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Re: Problem with daughter links [message #14805 is a reply to message #14800]

Mon, 27 May 2013 09:11

Ralf Kliemt
Messages: 507
Registered: May 2007
Location: GSI, Darmstadt

first-grade participant

From: *gsi.de

Hi Andreas,

Do you do anything to the aD, Kp nad pim candidate lists after combining but before comparing the masses?

Cheers
Ralf

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Re: Problem with daughter links [message #14807 is a reply to message #14805]

Mon, 27 May 2013 11:22

Andreas Pitka
Messages: 38
Registered: November 2011
Location: Gießen

continuous participant

From: *physik.uni-giessen.de

Hi,

thanks a lot for the replies. Smile

I was implicit fitting before showing the massing, the problem is only appearing when applying the PndKinVtxFitter.
Actually i was doing the following:

      for (int j=0;j<aD.GetLength();j++) 
      {
      counter++;	
      cout<<"--------------"<<endl;
      PndKinVtxFitter FitteraD(aD[j]);
      
      FitteraD.Fit();
      
      double mass_aD=aD[j].GetFit()->M();
      cout<<"Mass: "<<mass_aD<<endl;
      TLorentzVector d1_p4=aD[j].GetFit()->Daughter(0)->P4();   
      TLorentzVector d2_p4=aD[j].GetFit()->Daughter(1)->P4(); 
      TLorentzVector moth_p4=d1_p4+d2_p4;
      double mass_moth=moth_p4.Mag();
      cout<<"Mass by daughters P4: "<<mass_moth<<endl;
      }

But perhaps Ralf thats interresting for you:

Here is a list what happens with the different fitters:

PndKinVtx
- Fails, something is wrong with the fitted fourvectors.

PndVtxPRG with fast fitting:
- Works properly.

PndKinVtx
- Works (anything else would be bad for a pure kinematic fitter...)

PndChiVtxFitter, Pnd4CFitter and
PndVtxPRG with full fitting:
- Errors with:

Error in <TVectorT<double>::operator()>: Request index(23) outside vector range of 0 - 20

PndVtxFitter:
- Errors with:

PndVtxFitter::DoVertexFitWOCorr: 0 tracks
Error in <TMatrixTRow_const(const TMatrixT<Element> &,Int_t)>: row index out of bounds

Thanks again and sorry if i caused confusion

Andreas

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Re: Problem with daughter links [message #14818 is a reply to message #14800]

Tue, 28 May 2013 10:05

Ralf Kliemt
Messages: 507
Registered: May 2007
Location: GSI, Darmstadt

first-grade participant

From: *gsi.de

Hi Andreas,

I put a fix to PndKinVtxFitter. The fitted mother is now exactly the daughter's sum. I might have broken some feature with neutrals there, but that issue is tackled separately anyways.

Cheers
Ralf

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