cloning a TTree

Dear ROOTers,

I am trying to clone a TTree with some selections to copy only a subset of the original dataset.
The code I am using to do that in ROOT Version 5.10/00e and can be found in attachment to this email.
If necessary, please let me know if more information is needed to focus the problem.

The output root file is produced with the expected number of events, but the copied variables are not filled with the original values. What do I am missing?

Thank you, kind regards,

pietro