Options for the efficiency algorithm and how to set them

they refer to DaVinciEff v2r5 and higher ( DaVinci v8r0 and higher)

1. Options relative to the MC truth decays

 1.1 You must set the decay you are interested in for the MC
     truth part. If you do not do it the programs will stop 

     at initialization.

     EffXXX.MCDecay = "description of the decay according to
                       MCDecayFinder tool";

                       ( type std::string, def="" )

     A description of the syntax can be found in the doxygen
     detailed description of the MCDecayFinderTool

     A list of decay descriptors for the signal files generated

     can be found out of the physics web page

 1.2 You must "tag" (putting the character ^ before the 
     specified particles) the end decay particles in order
     to have the rec'tible/rec'ted numbers (see definition).
     The executable will stop after the first event if this

     is not done. 

     For example for Bs -> J/Psi (mumu) phi (KK) with possible

     radiative gamma where the stable particles are the muons and

     kaons you would write:

     EffXXX.MCDecay = "B_s0 -> (J/psi(1S) -> ^mu+ ^mu- {, gamma}) (phi(1020) -> ^K+ ^K-)"

     (note that the "tag" in not done in the decay descriptors 

      provided in the list)

 1.3 You can specify one parent particle type for which the decays

     has to originate, meaning that for the decay described in
     the EffXXX.MCDecay only those that will come from the particle
     specified here will be considered. This cannot be the head of the

     tree as specified in MCDecay because a particle cannot
     have itself as a parent.

     The default value = "Any", implies that the "parent" of the 
     decay of interest is not checked.

     EffXXX.MCDoIFromParent = "particle name from which the decay 

                               must come from";

                               ( type std::string, def="Any" )

     This can be used to look at partial decays of a B, for
     example for Ks that come from a B0 in which case one would 
     write:

     EffXXX.MCDecay         = "Ks -> ^pi+ ^pi-";
     EffXXX.MCDoIFromParent = "B0";
 

2. Options relative to the selected decay

 2.1 You must set the decay you are interested in for the selection
     part. At the moment no protection are implemented and it is

     directly delegated to the DecayFinder tool. This will be set

     in a future release similarly to the MC part.

     EffXXX.DecayFinder.Decay = "description of the decay according to
                                 DecayFinder tool";

                                ( type std::string, def="B0 -> pi+ pi-" )

 2.2 You must set where in the Transient Store the head of the selected

     decay is. Note that at the moment only a single location is used.

     EffXXX.SelLocation = "TES path where head particle for selected

                           decay is located";

                          ( type std::string, def="" )

 2.3 You can set a mass window for which separate numbers of selected and

     associated numbers will be reported.

     EffXXX.MotherMassLow = value of lower limit of mass window;

                            ( type double, def = 4.0 GeV )

     EffXXX.MotherMassUpp = value of upper limit of mass window;

                            ( type double, def = 6.0 GeV )

3. Options relative to the associated decay   

  To do the association the efficiency uses two associators at the
  same time (the Chi2 and the Composite Link). Note that at the
  moment for some decays with intermediate optional resonances only

  the Chi2 gives sensible results. 

  Property of the associators need to be set.

  Both the Chi2 and the Composite Link are forwarding where to find
  the input particles to the necessary algorithms.
  Hence only their "InputData" has to be set.

  You must set the InputData for both the composite link associator
  and for the chi2 associators.

  As an example for Bd->J/Psi(mumu)Ks the necessary options for the
  associators are:

    // Associator with Links
    EffBd2Jpsi2MuMu_Ks2PiPi.CompP2MCAsct.Location = "Phys/Relations/CompPart2MCfromLinks";
    EffBd2Jpsi2MuMu_Ks2PiPi.CompP2MCAsct.AlgorithmType = "CompositeParticle2MCLinks";
    EffBd2Jpsi2MuMu_Ks2PiPi.CompP2MCAsct.AlgorithmName = "CompositeParticle2MCLinks";
    CompositeParticle2MCLinks.InputData = { "Phys/JPsi/Particles",
                                            "Phys/Kshort/Particles",
                                            "Phys/B0/Particles" };

    // Associator with Chi2
    EffBd2Jpsi2MuMu_Ks2PiPi.Chi2P2MCAsct.Location = "Phys/Relations/Particle2MC";
    EffBd2Jpsi2MuMu_Ks2PiPi.Chi2P2MCAsct.AlgorithmType = "Particle2MCChi2";
    EffBd2Jpsi2MuMu_Ks2PiPi.Chi2P2MCAsct.AlgorithmName = "Particle2MCChi2";
    Particle2MCChi2.InputData  = { "Phys/B0/Particles" };

   Note that:
     - for the Composite link associator you need to specify all the TES
       locations where particles contributing to your decay are located
     - for the Chi2 associator it is sufficient to specify the TES location
       where the head of the decay tree is.