Draft: wangy/Adding gencut to Lb2Lhh channels
Create new dec-files that add vert tight gen-level cut to Lb_LambdaKK, Lb_LambdaPiPi, Lb_LambdaKPi channels.
Create new dec-files that add vert tight gen-level cut to Lb_LambdaKK, Lb_LambdaPiPi, Lb_LambdaKPi channels.