GSI Forum
GSI Helmholtzzentrum für Schwerionenforschung

Home » PANDA » PandaRoot » Bugs, Fixes, Releases » PndKinVtxFitter
PndKinVtxFitter [message #17159] Tue, 12 August 2014 08:48 Go to previous message
Alexandr Zinchenko is currently offline  Alexandr Zinchenko
Messages: 22
Registered: May 2009
occasional visitor
From: *
I was trying to apply a vertex constrained fit to a charmonium candidate (made of J/psi pi+ pi-)
The relevant analysis macro lines are as follows (based on tutorials/rho macros)

// *** combinatorics for J/psi -> mu+ mu-
jpsi.Combine(muplus, muminus);

// *** combinatorics for psi(2S) -> J/psi pi+ pi-
psi2s.Combine(jpsi, piplus, piminus);

// ***
// *** do VERTEX FIT (psi(2s))
// ***

for (j = psi2s.GetLength()-1; j >= 0; --j) {
PndKinVtxFitter vtxfitter(psi2s[j]); // instantiate a vertex fitter

The printout from PndKinVtxFitter code (activated by the verbosity flag) is:

Initial vertex Position is -0.00141313 -0.0154373 -0.0183913
iteration Number 0
vertex Position is -nan -nan -nan
chi2 in iterartion -nan
iteration Number 1
vertex Position is -nan -nan -nan

Am I doing something wrong or the fitter does not work for such particle combination (1 neutral composite and 2 charged)?
Read Message
Read Message
Read Message
Read Message
Previous Topic: [FIXED] EvtGen J/psi decay
Next Topic: [FIXED] Possible bug in scrut14 release?
Goto Forum:

Current Time: Sun Jun 23 06:53:09 CEST 2024

Total time taken to generate the page: 0.00952 seconds