Hi,
Thanks for the reply.
I modified following your recommendation.
However my main issue is still happening, my codes corrupts the input data (the TTree) if I use “UPDATE”.
Also, indeed the structure is TTree but Geant use Ntuples. I used the Ntuple class previously since it was the usual definition used in few examples of Plot.C macros provided by Geant.
No changes seems to affect the code but I corrupt the my data.
I would be really grateful if you could help me more.
Thanks!