select/reject commands

[semlalisouad]

Dear Madanalysis team,
I have a question about reject/select commands. I have generated :

• signal with bbjjmu+mu- in the final state.
• background: Dy +jets (pp > mu+ mu- jj bb~)
  After the detector simulation, I used the ma5-expert plugin to check the nb of events normalized, after applying the cuts.

For the signal:
select m(b[1] b[2] j[1] j[2] mu[1] mu[2])< 350 GeV => nb of events dropped from 12.94 to 0.001
reject m(b[1] b[2] j[1] j[2] mu[1] mu[2]) > 350 GeV => nb of events remained 12.94

For the background:
select m(b[1] b[2] j[1] j[2] mu[1] mu[2]) < 350 GeV => nb of events dropped from 490.77 to 4.56
reject m(b[1] b[2] j[1] j[2] mu[1] mu[2]) > 350 GeV => nb of events dropped from 490.77 to 490.200

Why there is such a difference between "select" and "reject"? I would be grateful for any help to alleviate the confusion.

Many thanks

Best
Souad