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
Topic attachments
I Attachment Action Size Date Who Comment
PIPPIM_INVM_COSTH_PT.gifgif PIPPIM_INVM_COSTH_PT.gif manage 38.0 K 06 Sep 2014 - 13:37 GosiaSudol pi+pi- invaraint mass vs. cos Theta in CM after cut on miss cut
PIPPIM_INV_MASS.gifgif PIPPIM_INV_MASS.gif manage 10.4 K 06 Sep 2014 - 13:37 GosiaSudol pi+pi- invaraint mass
PIPPIM_MISS_MASS2_COSTH_PT.gifgif PIPPIM_MISS_MASS2_COSTH_PT.gif manage 35.1 K 06 Sep 2014 - 13:37 GosiaSudol pi+pi- missing mass2 vs. pi+pi- cosTheta cm using PionTracker
PIPPIM_MISS_MASS2_PT.gifgif PIPPIM_MISS_MASS2_PT.gif manage 12.2 K 06 Sep 2014 - 13:38 GosiaSudol pi+pi- missing mass2 using PionTracker and not using
PIPPIM_MISS_MASS2_PT_INVM.gifgif PIPPIM_MISS_MASS2_PT_INVM.gif manage 26.2 K 06 Sep 2014 - 13:38 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 6.5 K 09 Sep 2014 - 17:17 GosiaSudol pi+pi- missing mass, C + PE at 800 MeV
Topic revision: r3 - 09 Sep 2014, GosiaSudol
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Hades Wiki? Send feedback
Imprint (in German)
Privacy Policy (in German)