Photons for TLA

This is our first implementation of a TLA Sequence in the Egamma HLT slice that operates by making a deep copy of the HLT_FastPhoton container (xAOD::TrigPhotonContainer) produced by the FastPhoton reconstruction step, and saving the resulting container to the output.

The TLA Sequence is defined and configured in Trigger/TriggerCommon/TriggerMenuMT/python/Egamma/TLAPhotonSequenceSetup.py and is composed of:

• an algorithm which creates the deep copy of the input photons and pushes photons above a certain energy to the output container. [configured in Trigger/TrigHypothesis/TrigEgammaHypo/python/TrigEgammaTLAPhotonFexMTConfig.py and relevant source code in Trigger/TrigHypothesis/TrigEgammaHypo/src/]
• a HypoAlg and a HypoTool, which do nothing but to associate the TrigCompositeUtils::Decision* object set in the previous chain steps to the photons passing the selector implemented in the previous steps [source code in Trigger/TrigHypothesis/TrigEgammaHypo/src/]

At the current stage, the "TLA Step" is implemented as an additional chain step that is appended to the existing list of steps only for chains with the tag PhotonDS in their name. The addition is performed at line 110 and following of Trigger/TriggerCommon/TriggerMenuMT/python/Egamma/PhotonChainConfiguration.py.

We are currently testing our implementation through the new HLT_PhotonDS_g35_loose_L1EM22VHI chain, defined at line 211 of LS2_v1.py.

------ MAY 2nd EDIT ------

Following the comments on this thread and on ATR-19317, we altered the configuration of the sequence in TLAPhotonSequenceSetup.py to have the Selector (TrigEgammaTLAPhotonFex) run within the event view produced by the precision photon reconstruction step following the examples of both fastPhotonMenuSequence and precisionPhotonMenu sequence https://acode-browser1.usatlas.bnl.gov/lxr/source/athena/Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Egamma/PhotonMenuSequences.py#L76.

Currently, the test run on the PhotonDS chain fails, likely because the input collection again cannot be accessed. The full warning level log printout can be found in the attached file log_warning_2.05.txt