EEMC has eta coverage 1.09<eta<2 and helps to reject QCD BG events where the jet opposite in phi from the e+/e- candidates.

Since there is no ENDCAP in east side of STAR any background e+/e- candidate that has an opposite side jet with -2< eta <-1.09  would be a good signal even, due to opposite side jet escape the detection.

Mtd to estimate this BG,

We calculate the BG events that are rejected by the real EEMC of STAR for eath eta bin and assumed to be same as the BG that would have been rejected by the fictitious "second endcap"

Quick step 

1) run the Analysis 2 times,  First using ETOW  as aveto in the near-side and pt balance cuts and then without using the ETOW in these cuts.

             black - withOut EEMC   , Blue -- with EEMC                                                     Red -  Difference ( without EEMC - with EEMC )

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2)  remove any Z-ee contamination using MC Z samples

3)  traeat background events rejected by the real EEMC which are measured in the positive Eta bins correspond to BG events that would be removed from the signal yield in the negative Eta bin by a fictitious EEMC on the east side of STAR.  ===> SUBSTRACT THE POSITIVE ETA BIN SECOND EEMC BG YEILD  STATISTICALLY FROM THE SIGNAL YEILD IN THE NEGATIVE ETA BINS.