2pion events produced by Witek PAT framework. Roo files with n-tuple including pi+pi- reconstruction is placed
/hera/hades/user/przygoda/PAT2/out/exp/186/hadron186.root
From 46 MLN events around 200 k di-pion pairs were reconstructed after simple pid cuts on clearly visible pions
in mass vs momentum correlation (see below- b.t.w note very clear electron contribution)
- positive_PID:
- negative_pid:
Momentum and polar angle distributions of negative and positive pions are presented below (due to the reversed polarity of the magnetic field negative pions are bent to smaller angles)
- theta_distributions:
- momentum distributions:
- Event vertex distribution:
From the simulation done for pion experiment one can estimate number of expected di-pion (see presentation
in
https://hades-wiki.gsi.de/foswiki/bin/view/Meetings/HadesPion28052014
For 1MLN pion emerging from last Q9 we expect rougly 8-10% M2&&START triggers which corresponds to 100k events and around 350 di-pion pairs (for 7% tungsten target-rougly 7 times more than for LH2)
For the 46 MLN collected events we should then expect 160k pions
We see 200k, which looks quite fine