2pion events produced by Witek PAT framework. Roo files with n-tuple including pi+pi- reconstruction is placed


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
I Attachment Action Size Date Who Comment
ev_vertex_z.gifgif ev_vertex_z.gif manage 4 K 2014-07-07 - 10:01 PiotrSalabura Event vertex distribution
negative_pid.gifgif negative_pid.gif manage 8 K 2014-07-07 - 09:56 PiotrSalabura negative_pid
pip_pim_ID_mon.gifgif pip_pim_ID_mon.gif manage 4 K 2014-07-07 - 10:00 PiotrSalabura momentum distributions
pip_pim_ID_theta.gifgif pip_pim_ID_theta.gif manage 6 K 2014-07-07 - 10:00 PiotrSalabura theta_distributions
positive_pid.gifgif positive_pid.gif manage 11 K 2014-07-07 - 09:56 PiotrSalabura positive_PID
Topic revision: r1 - 2014-07-07, PiotrSalabura
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