DerivationFrameworkMCTruth: keep all daughters of TruthTausWithDecayParticles

Hello,

This MR changes the number of generations of daughter particles retained when building the TruthTausWithDecayParticles/TruthTausWithDecayVertices collections. It was previously set to 1 but this can lead to pathological situations, e.g. when the truth tau decays to kaons: if we don't know what the kaon decays to, we cannot properly compute the truth visible tau momentum. When set to -1, we retain all generations, and this seems to fix the problem.

A priori, we can now recompute the various decorations of TruthTaus using TruthTausWithDecayParticles/TruthTausWithDecayVertices, such as pt/eta/phi/m_vis, the number of neutral/charged pions, ... We will need to rework a bit BuildTruthTaus to do this. The only variables we don't seem to get is polarizationPhi and polarizationTheta decorations, they exist for TruthTaus but not TruthTausWithDecayParticles, however these seem to always be 0. We'll still have to check we can rerun photon dressing for TruthTausWithDecayParticles.

Marking as urgent as we'd need this for the upcoming DAOD_PHYS production that is imminent (ATLASDPD-2017).

Tagging @ademaria and @lfiorini .

Cheers, Bertrand

added urgent label

This merge request affects 1 package:

• PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth

This merge request affects 1 file:

• PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/python/MCTruthCommonConfig.py

Adding @zmarshal ,@emmat ,@jcatmore as watchers

added Derivation main review-pending-level-1 labels

CI Result SUCCESS (hash 7dd3e5a6)

	Athena
externals
cmake
make
tests

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For experts only: Jenkins output [CI-MERGE-REQUEST-EL9 2826]

Seems straight-forward.

Cheers, Anne (L1)

added review-approved label and removed review-pending-level-1 label

added review-approved-point1 label

merged

mentioned in commit 4a3ffac5