D0:MET: how to get access to right MET

In D0 framework, MET issue is very tricky. I am sick of how to get access to it and always spent lots of time on it. Here, I would try my best to clarify it:

- MET has several components: CH, JES, MU, Bad Jets. Based on your study, you could choose different configuration, usually, we use:

CH+JES+EM+MU

-However, for JES, we have corrJet, corrmuJet, smear_corrJet, smear_corrmuJET etc, here Jet is JCCA or JCCB. For MU, we have MU or CALOMU.

- But a point making things more complicated is: in JES, sometime we apply muon correction which may be counted later in MET, in order to avoid double contributions from muon correction, we should keep in mind it!!