The mass spectra for phi at 27 GeV with different Tof m2 cut:

1) NoTofCut_auau27_phi_invmass_cent9_TAllMix.pdf:
    No TofCut, EvtMix, there are some strange step before the phi peak, which not appear for Rotate Method.

2) auau27_phi_invmass_EvtMixTof.pdf:
   EvtMix, m2(0.15,0.5) for all pt,  sample000
   the step disappear, the 1.07 resonance peak shift to ~1.04.

3) auau27_phi_invmass_EvtMixTofPt0_4.pdf
   EvtMix m2(0.15,0.5) for pt>0.4,  sample000

4)auau27_phi_invmass_EvtMixTofTightPt0_4.pdf
  EvtMix  tight cut: m2(0.15,0.35) pt>0.4 sample000