Add code for leading/ subleading lepton pT

[rsamconn]

Histograms

1. Leading pair pT
2. Subleading pair pT
3. Quadruplet pT

Questions

1. Where to implement in the code - in the particle check loop or in the bitmask check? The former requires only variables, the latter requires variables and histograms
2. Divide by electrons vs muons? Or just look at overall?
3. Do leading and subleading for every pair?
4. Do leading pair vs subleading pair? Is pair-pT just the sum of pT's of each lepton in the pair?
5. How do you compare events where one pair is muons and one pair is electrons?

Code implentation Simplest:

• Ignore e/u distinction
• Only compare pairs (not individual leptons in a pair)
• Save pair pT as variables, then compare and fill leading/subleading histograms accordingly Separate e/u by sum of pdgIDs:
• eeee -> 44 (or 22)
• uuuu -> 52 (or 26)
• eeuu -> 48 (or 24)

[rsamconn]

Completed during invariant mass work. See here https://github.com/ujphys/4lMET_Ana/pull/33