The goal of this study is to investigate, for a centrality, at which eta range, the truncated nmip method starts to become invalid. It is hard to determine the accurate values but some qualitative conclusions can be drawn:

1.at 27 GeV, double hits make up an important part of the total hits at all the centralities and eta ranges. 

2.There are more multiple hits (nMIP=3 and above) in the small and large |eta|. At small eta, multiple hits are due to the large amount of the produced particles, while at large eta, it is due to the spectators. 

3...

 
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Following is the percentage of different nMIP values:

Following plot on the right is the v1(eta) measured with nMIPMax=2(blue), nMIPMax=3(red) and nMIP fitting (black).
The left plot tries to show the influence of truncating the nMip. The y axis is the ratio: