Skip to content

LoKiPhysMC: add custom mc-truth matcher for photons

Vanya Belyaev requested to merge vanya-lokiphysmc-v0 into master
  • add new algorithm MCTuthPhoton to create "custom" MC-truth links for some interesting MC-photons and neutral protoparticles

e.g. build MC-truth for photons from Bs -> phi(1020) gamma decays:

    from Configurables import LoKi__MCTruthPhoton as CustomPP2MC 
     
    alg = CustomPP2MC('Custom')
    alg.EnergyFraction  = (0.1,2)
    alg.MaxChi2         = 4
    ##
    alg.PropertiesPrint = True 
    alg.Preambulo = [
        "from GaudiKernel.SystemOfUnits import GeV, MeV, cm" ,
        ]
    alg.Code = """
    ( MCPT > 100 * MeV ) & MCDECTREE ( 'Beauty -> (phi(1020) => K+ K-) ^gamma' ) 
    """

Or a bit more generic case:

    alg.Preambulo = [
        "from GaudiKernel.SystemOfUnits import GeV, MeV, cm" ,
        "from LoKiCore.functions import in_range" 
        ]
    alg.Code = """
    ( MCPZ >  1   * GeV             ) &
    ( MCPT >  0.1 * GeV             ) &
    MCFROMDECAYS                      &
    ( abs ( MCPX / MCPZ  ) < 0.350  ) &
    ( abs ( MCPY / MCPZ  ) < 0.250  ) &
    in_range ( -20*cm , MCVFASPF( MCVZ ) , 20*cm ) 
    """

MC-mathching is performed using the spatial matching of photon direction and LHCb::CaloPosition ( using data on center&spread) using chi2. for inner/middle zones chi2<1 has almost 100% efficiency, for outer zone the distribution is a bit wider, but efficiency for chi2<2 requirement is close to 100%

       150   ++----+----+----+----+----+----+----+----+----+----+  
              ||    .    .    .    .    .    .    .    .    .    |  
              ||    .    .    .    .    .    .    .    .    .    |  
              ||    .    .    .    .    .    .    .    .    .    |  
              ||    .    .    .    .    .    .    .    .    .    |  
        112   ++.................................................+  
              ||    .    .    .    .    .    .    .    .    .    |  
              |**   .    .    .    .    .    .    .    .    .    |  
              |***  .    .    .    .    .    .    .    .    .    |  
              |***  .    .    .    .    .    .    .    .    .    |  
         75   +***...............................................+  
              |***  .    .    .    .    .    .    .    .    .    |  
              |***  .    .    .    .    .    .    .    .    .    |  
              |**** .    .    .    .    .    .    .    .    .    |  
              |**** .    .    .    .    .    .    .    .    .    |  
       37.5   +****..............................................+  
              |*****.    .    .    .    .    .    .    .    .    |  
              |******    .    .    .    .    .    .    .    .    |  
              |********* .    .    .    .    .    .    .    .    |  
              |***********    .    .    .    .    .    .    .    |  
          0 *-++----+----+***************************************->*
            U                                                       
            N                                                      O
            D                                                      V
            E                                                      E
            R                                                      R
            F                                                      F
            L       0    0    1    1         2    2    3    3      L
            O       .    .    .    .         .    .    .    .      O
            W 00    4    8    2    6    2    4    8    2    6    4 W

Optionally the criteria on E(mc)/E(calo) can be applied.

Typical usage, e.g. in Bender:

  bender_alg        = ...
  bender_alg.PP2MCs = [ 
     'Relations/Rec/ProtoP/Charged'  ,
     'Relations/Rec/ProtoP/Upstream' ,
     'Relations/Rec/ProtoP/Custom'   ]

or for mcMatch utility:

    ... = mcMatch ( ... , strings( [
     'Relations/Rec/ProtoP/Charged'  ,
     'Relations/Rec/ProtoP/Upstream' ,
     'Relations/Rec/ProtoP/Custom'   ] ) , ... )

Merge request reports