Example ForceDecay_Lambda_Neutron_Dalitz

This is a simple simulation example showing how to force a specific particle decay chain. To simplify the example, we will use a Box generator to inject Lambda0 particles in the simulation.

What we want to achieve is a forced decay chain of the Lambda0

Lambda0 --> n pi0 --> n e+ e- gamma

Given that both the Lambda0 and the pi0 are by default decayed by Geant, we have to turn on the external decayer for these particles. This can be done with

--configKeyValues 'SimUserDecay.pdg=3122 111'

On top of that we have to setup the external decayer to perform the decay forcing the channels we desire. The default external decayer configuration is loaded from

${O2_ROOT}/share/Generators/pythia8/decays/base.cfg
which is assigned to the slot #0 of the configuration parameter 'DecayerPythia8.config'.

What we want to do is to add on top of the default configuration some extra settings that are provided in the decay_lambda_neutron_dalitz.cfg file. This can be done with

--configKeyValues 'DecayerPythia8.config[1]=decay_lambda_neutron_dalitz.cfg'