{    
  // Cuts to pick out specific regions. 
  TCut cCSC    = "region==1 || region==2 || ((region==5 || region==6) && sqrt(x*x+y*y) < 211.)";
  TCut cEITGC1 = "region==3 || region==4";
  TCut cEIMDT1 = "(region==5 || region==6) && sqrt(x*x+y*y) > 211.";
  TCut cEITGC2 = "region==7 || region==8";
  TCut cEIMDT2 = "region==9 || region==10";
  TCut cEITGC  = cEITGC1 || cEITGC2;
  TCut cEIMDT  = cEIMDT1 || cEIMDT2;
  TCut cBIS8   = "region==11 || region==12";
  TCut cEMTGC1 = "region==13 || region==14";
  TCut cEMMDT  = "region==15 || region==16";
  TCut cEMTGC2 = "region==17 || region==18";
  TCut cEMTGC  = cEMTGC1 || cEMTGC2;
  TCut cEM     = cEMTGC1 || cEMMDT || cEMTGC2;
  TCut cEO     = "region==19 || region==20";
  TCut cEE     = "region==21 || region==22";
  TCut cBI     = cBIS8 || "region==23";
  TCut cBEE    = "region==24 || region==25";
  TCut cBM     = "region==26";
  TCut cBO     = "region==27";

  // Define two dditional regions for EI used primarily for upgrade studies. 
  // cEI1 = CSC or MDT1 (out to r ~ 450 cm).
  TCut cEI1 = cCSC || cEIMDT1;
  // cEI2 = CSC or MDT1 or MDT2 (out to r ~ 650 cm).
  TCut cEI2 = cCSC || cEIMDT;
 
}