Selection of the elastic events has applied done on the following distributions

• 175 < delta_phi < 185
• tanTheta*tanTheta > 1
• pion and proton identification via cuts on mass
• ppi- missing mass2 > 1.35

Please note that in comparison to the beam momentum 690MeV/c

we see 30MeV upward shift for the mean value of ppi- invariant mass, as expected from

higher momentum of 748 MeV /c

As for the 690 MeV /c point mean value of CMS is shifted by 20 MeV below expected 1.526 MeV. Most likely due to energy loss of pions and protons in target.

Resolution of CMS reconstruction 1%

Total number of elastic scattering events ~ 5 MLN ,

Overlay of ppi- missing mass^2 from PE (blue line) target and C (red line) one.

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

Non-elastic events

Overlay of ppi- missing mass^2 for non-elastic events from PE (blue line) target and C (red line) one.

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

Fit of the ppi- missing mass gives a mean position of the pi0 peak at 2.68e-2 (expected 1.93e-2 ) - it corresponds to 20 MeV too large pi0 mass- and

total number of ppi-pi0 events (after background subtraction) of 0.587 MLN