Create an ascii file containing events that are inside a cut

Roofit and RooStats
1

Dear all,

I’m a bit new in programming in Root and I have actually found the first wall to crash :cry: . I will explain in detail what I have and what I need.

The output of my experiments is an ascci file with four columns (each column corresponding with one detector) and n rows, where each row is an alpha particle delivering a signal in each detector. So each alpha creates a signal in all four channels at the same time. With this ascii file I have written a script to create a root file (I send you attached) with one ntuple and four branches (namely ch0, ch1, ch2 and ch3).

Out of all events that I have in the root file, I’m only interested in those which are inside a bi-dimensional cut that I draw with the “graphical cut” when plotting ch1 vs ch3 (have a look to the screenshot).

mycut.jpg1596×1179 296 KB

And now the question is the following: is it possible to write a script that creates an ascii file containing only the events within the graphical cut?. I mean, those from ch1 and ch3 that are inside the cut and the corresponding ones from ch0 and ch2. The format should be four columns (ch0 ch1 ch2 ch3) and m rows.

Thanks for the help and best regards,
Jose Manuel.
Run046_mod.root (338 Bytes)

2

I all again,

I made a mistake in the previous post. I have one branch with four leaves (each leave is a variable), not four branches.

Bests,
Jose Manuel.

3

see:
root.cern.ch/root/roottalk/roottalk07/0417.html

4

Dear Couet,

thanks for the reply. Unfortunately this two commands gave me a log file containing all data in my tree (so this is basically the same one as I used to create the tree). What I need is the same but containing only events inside the graphical cut “mycut”. Is it possible to add any condition to Scan to focus on that?.

Best regards,
Jose Manuel.

5

Look at the Scan() calling sequence:
root.cern.ch/root/html/TTree.html#TTree:Scan

the 2nd parameter is the selection put your cuts there.

6

Dear Couet,

many many thanks!!!.

ntuple.Scan("*","mycut"); > scan_cut.log

works nicelly.

Cheers,
Jose Manuel.