All plots are done using pi+, pi- PID cut and opening angle between pi+pi- to

be greater than 5 degree.

For the pi+pi invariant mass plot below a cut on the missing mass of pi+pi-

to be within (0.8 - 1.03) is applied

One can see a clear improvement in missing mass resolution when incoming pion momentum is taken from the PionTracker reconstruction (blue line) (red line- only one fixed value of pi- momentum of 690 MeV is used).

Overlay of pi+pi- missing mass from PE (blue line) target and C (red line) one.

Spectra are normalized to yield in the ragio far from the peak position.