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Definition of Centrality in the Event Generator

Centrality in event generator is defined using impact parameter of collision b.
The range of impact parameter used in MC simultaion is defined in dataset name (and subdirectory name) like '/b0_3/','/b0_12/' etc. where b0_3 means that impact parameter b has been taken in the range 0-3 fm.

Centrality Notation in the directoryRange of impact parameterEstimated percentage of HIJING events
(from Ron)
minbias /b0_10/ up to /b0_20/ 0-10 fm, 0-20 fm
central /b0_3/ up to /b0_6/ 0-3 fm, 0-6 fm ~20% for b=0-6 fm
midcentral /b3_6/ 3-6 fm ~13%
midperipheral /b6_9/ 6-9 fm ~30%
peripheral /b9_12/, /b8_15/ 9-12 fm, 8-15 fm ~40% for b=9-12 fm

Lidia Didenko