𝜈 and 𝜇 mixed simulation

This section explains how to a mixed simulation with signal and background is performed in sndsw and FEDRA.

The starting point is to have two simulations, one for signal (neutrino) and one for background (passing muons).

For the latter, we pick up a particular type of muon background simulation: muon background simulation with different densities, currently $10^3, \,10^4, \,10^5\, \mu/cm^2$ densities are available. Further simulations can be done through the script make_newFLUKA.C located here.

NOTE: be aware that there is a maximum number of muons that can be re-simulated according to the number of entries of the original FLUKA file.

The script that allows to provide the mixed simulation is fromsndsw2FEDRA_muonduplication.C, located here.

This script allows to mix a maximum number of neutrinos nnuevents = 100 with a certain number of muons according to a given density, nmuonsxnu = 100.

So according to the density, for every neutrino interaction occurring in the SND@LHC emulsion target, nmuonsxnu muons are placed around it, given its x-y position.

NOTE: for each background muon an eventID multiplier is associated, thus neutrino eventID will start from 0 whereas the background muon ones will start from evID_multiplier = 1e+3.

Once the muon positioning is done, a conversion to FEDRA of the simulated tracks is performed.