trigger: E7A_2RL3_RT3_RL5 or E7B_2RL3_RT3_RL5 (from CSskim-JPSI-%raw)
 + 2 EM clusters with:
  EM fraction > 0.9
  isolation < 0.15
  HMx8 < 75

 + each cluster within 0.2 in eta/phi space of a loose road electron (this is essentially a track-match).
 + invariant mass cut