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 800 MeV is used).


From a fit to the missing mass spectrum Total number of pi+pi- events (after background -pol3-subtraction) amounts to 620 k

Mean value of the missing peak is 0.914, corresponding to the neutron mass of 957 MeV (18 MeV to high..)

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.

-- GosiaSudol - 06 Sep 2014
I Attachment Action Size Date Who Comment
PIPPIM_INVM_COSTH_PT.gifgif PIPPIM_INVM_COSTH_PT.gif manage 38 K 2014-09-06 - 15:37 GosiaSudol pi+pi- invaraint mass vs. cos Theta in CM after cut on miss cut
PIPPIM_INV_MASS.gifgif PIPPIM_INV_MASS.gif manage 10 K 2014-09-06 - 15:37 GosiaSudol pi+pi- invaraint mass
PIPPIM_MISS_MASS2_COSTH_PT.gifgif PIPPIM_MISS_MASS2_COSTH_PT.gif manage 35 K 2014-09-06 - 15:37 GosiaSudol pi+pi- missing mass2 vs. pi+pi- cosTheta cm using PionTracker
PIPPIM_MISS_MASS2_PT.gifgif PIPPIM_MISS_MASS2_PT.gif manage 12 K 2014-09-06 - 15:38 GosiaSudol pi+pi- missing mass2 using PionTracker and not using
PIPPIM_MISS_MASS2_PT_INVM.gifgif PIPPIM_MISS_MASS2_PT_INVM.gif manage 26 K 2014-09-06 - 15:38 GosiaSudol pi+pi- missing mass2 vs. pi+pi- invariant mass using PionTracker
PIPPIM_miss_mass2_C_PE_800.gifgif PIPPIM_miss_mass2_C_PE_800.gif manage 6 K 2014-09-09 - 19:17 GosiaSudol pi+pi- missing mass, C + PE at 800 MeV
Topic revision: r3 - 2014-09-09, GosiaSudol
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