M-C study of efficiency of Pi0 and Eta reconstruction ( from towers only)

The objective of this page is to understand some features of the reconstructed real Pi0 taken with the MinB and E-HT triggers, posted at the calibration page The reco params for M-C events were identical: seed energy of 0.6 GeV, seed/total energy >0.7, pi0 inv mass cut=0.07-0.22 GeV,scale factor SF=0.04 (measured energy/incident energy).

Note, the cluster finder has been improved: energy of towers between the clusters seed is divided proportionally to the seeds energies (before it was just 1/2 or 1/3).

The M-C simulation of one meson per event has been performed. Mesons were thrown with fixed pT and uniform distribution over eta and phi directions: eta=1.05-2.0, phi= 3.456-5.445 radians, to cover 4 sectors of EEMC.

Observations:
- the total energy of reconstructed pi0 is about 85% of the incident energy.
- the shape of Z- and energy-distributions for pi0 with pT=0.7 GeV is very close to the real one for the MinB trigger.
- the shape of Z-distribution for simulated pi0 with pT of 2.5 and 3.5 GeV/c, resembles the ones for E-HT1 and E-HT2 triggered data, however the reco pT for real event is rather 1.5 and 2.5 GeV/c.
- a significant fraction of reconstructed pi0 may be a daughter pi0 from the decay of eta-meson in to pi+ pi- pi0
- reconstructed invariant mass grows for Z>0.6 .

Six panels below show:
-top left: invariant mass spectrum for all events,
-top mid: energy of pi0, after invM cut =[0.05,0.22] GeV
-top right: transverse momentum of pi0, after invM cut
-bottom left: energy shearing Z=|E1-E2|/(E1+E2) of 2 gammas, after invM cut
-bottom mid: opening angle of 2 gammas, after invM cut
-bottom right: pseudo-rapidity distrib. of pi0, after invM cut
Green histos represent mixed events.
The following spectra are for pi0 , later for eta-meson, and the last one is for uncorrelated gamma pairs with pT of 0.2-3.5 GeV/c.

M-C for pi0 with fixed pT 5000 events were generated each time.
pt/GeV=0_7 GeV/c;    Npeak= 243 ;     invM fit=0.139 +/- 0.002 GeV;    all.ps , invMcut.ps
pt/GeV=1_0 GeV/c;    Npeak= 803 ;     invM fit=0.131 +/- 0.001 GeV;    all.ps , invMcut.ps
pt/GeV=1_5 GeV/c;    Npeak= 1212 ;     invM fit=0.137 +/- 0.001 GeV;    all.ps , invMcut.ps
pt/GeV=2_0 GeV/c;    Npeak= 937 ;     invM fit=0.147 +/- 0.001 GeV;    all.ps , invMcut.ps
pt/GeV=2_5 GeV/c;    Npeak= 595 ;     invM fit=0.159 +/- 0.001 GeV;    all.ps , invMcut.ps
pt/GeV=3_0 GeV/c;    Npeak= 302 ;     invM fit=0.166 +/- 0.002 GeV;    all.ps , invMcut.ps
pt/GeV=3_5 GeV/c;    Npeak= 163 ;     invM fit=0.172 +/- 0.002 GeV;    all.ps , invMcut.ps
pt/GeV=4_0 GeV/c;    Npeak= 94 ;     invM fit=0.176 +/- 0.003 GeV;    all.ps , invMcut.ps
pt/GeV=5_0 GeV/c;    Npeak= 33 ;     invM fit=0.202 +/- 0.022 GeV;    all.ps , invMcut.ps

M-C for eta-meson with fixed pT 5000 events were generated each time.
pt/GeV=1_5 GeV/c;    Npeak= 580 ;     invM fit=0.124 +/- 0.007 GeV;    all.ps , invMcut.ps
pt/GeV=2_0 GeV/c;    Npeak= 943 ;     invM fit=0.137 +/- 0.002 GeV;    all.ps , invMcut.ps
pt/GeV=2_5 GeV/c;    Npeak= 1099 ;     invM fit=0.144 +/- 0.002 GeV;    all.ps , invMcut.ps
pt/GeV=3_0 GeV/c;    Npeak= 1027 ;     invM fit=0.153 +/- 0.002 GeV;    all.ps , invMcut.ps
pt/GeV=4_0 GeV/c;    Npeak= 630 ;     invM fit=0.167 +/- 0.004 GeV;    all.ps , invMcut.ps
pt/GeV=5_0 GeV/c;    Npeak= 344 ;     invM fit=0.181 +/- 0.012 GeV;    all.ps , invMcut.ps
pt/GeV=6_0 GeV/c;    Npeak= 205 ;     invM fit=0.173 +/- 0.014 GeV;    all.ps , invMcut.ps

M-C for par of uncorrelated gammas with uniform pT=0.2-3.5 GeV/c 20000 events were generated each time.
gg pT=0.2-3.5 GeV/c;    Npeak= 568 ;     invM fit=0.189 +/- 0.014 GeV;    all.ps , invMcut.ps
Script used for event processing zniwaMC.C .
Script used for generation of plots plPi0.C .