| Re: Psi3770 study with run981 tpc mode [message #12320 is a reply to message #12313] |
Thu, 21 July 2011 14:44   |
donghee
Messages: 385
Registered: January 2009
Location: Germnay
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first-grade participant |
From: *kph.uni-mainz.de
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Dear Stefano,
I'm using vertex fitter for D- in following procedure.
kip is positive kaon candidate and pim is negative pion candidate, respectively.
Then I do
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Dminus.Combine(kap, pim, pim);
PndKinVtxFitter Dmvtxfitter(Dminus[j]);
Dmvtxfitter.Fit();
double chi2 = Dmvtxfitter.GlobalChi2();
unsigned ndf = 1;
TChisqConsistency cons(chi2,ndf);
double prob = cons.Likelihood();
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Concerning resolution issue, if I have wrongly used the vertex fit, then I can understand bad resolution of D+ and D-.
but if I was using correctly the fit function, then I have to have oder of ~100 micrometer = 0.1mm = 0.01cm
I have still ~1.4mm(=0.14cm) after subtracting value between
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TVector3 Dvertex = (TVector3)mckaontrack->GetStartVertex();
TVector3 DpVtx = Dpvtxfit->Pos();
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Unit is here cm... because the smearing is visible with same unit in the D vertex distribution.
Upper plots are generated true vertex of D, and belows are reconstructed one, as I show you already few times.
I will check some bug..
Best wishes,
Donghee
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