Split lessons and rename

_episodes/03-FindingTriggerInfo.md

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+---
+title: "Finding information about a trigger path"
+teaching: 10
+exercises: 10
+objectives:
+- "Learn different ways to look up information about a trigger path"
+---
+> ## Prerequisites
+> Set up your machine following instructions in [setup][lesson-setup] first.
+{: .prereq}
+
+### Find the L1 seed of the MET HLT path
+There are different ways to learn which is the L1 seed of a specific HLT path. Two examples will be tested in this exercise:
+ * looking into [OMS](https://cmsoms.cern.ch/);
+ * looking into [web-based confdb](https://hlt-config-editor-confdbv3.app.cern.ch/);
+ * inspecting a HLT configuration.
+
+In the context of this exercise, we will retrieve the information of the `HLT_PFMET170_HBHECleaned_v*` path from OMS for a specific run (`run 284043`) and HLT configuration (`/cdaq/physics/Run2016/25ns15e33/v4.2.3/HLT/V2`).
+
+### OMS method
+As a first step, connect to [OMS](https://cmsoms.cern.ch/cms/runs/report?cms_run=284043&cms_run_sequence=GLOBAL-RUN) 
+ * Click on `"Runs > Triggers > HLT Path Report"`, 
+ * Use search option at the bottom left ("FILTER > Path Name") to look for `HLT_PFMET170_HBHECleaned_v*`.
+ * Find the information about the L1 seed names of the HLT path of interest. 
+
+Then move to the L1 Trigger rate page in OMS and search for the L1 seeds there to have a look at the rates and prescales of these L1 seeds.<br>
+(Note that you might need to increase the number of rows at the bottom of the page to find them.) 
+### Web-based confdb
+The [web-based confdb](https://hlt-config-editor-confdbv3.app.cern.ch/) is a web-based GUI of the database that holds all of CMS HLT configurations.<br>
+One can **inspect** any given HLT menu without downloading one or connecting to the database.<br>
+More information about the web-based confdb can be found in these [slides](https://indico.cern.ch/event/1230321/contributions/5177149/attachments/2580137/4450016/webbased%20confdb.pdf)
+
+Let's try to find the `/cdaq/physics/Run2016/25ns15e33/v4.2.3/HLT/V2` menu in the GUI.
+ * Connect to [https://hlt-config-editor-confdbv3.app.cern.ch/](https://hlt-config-editor-confdbv3.app.cern.ch/)
+ * Click "Configurations > Open remote"
+ * In the drop-down menu, select `online`
+ * Follow the directory of the menu `/cdaq/physics/Run2016/25ns15e33/v4.2.3/`
+ * Select "V2" from the side penal, and click "OK"
+
+After retriving from the DB, you can see all the paths. 
+ * Type the name of the path `HLT_PFMET170_HBHECleaned` into the search box in the left panel
+ * Expand the path. This shows all the **modules** that the HLT path will run in sequence.
+ * The L1 seed of a HLT path is always the first module (after the `HLTBeginSequence`) starting with the name `hltL1sXXXX`
+ * Click on `hltL1sETM50ToETM120`
+ * In the right panel, the `L1SeedsLogicalExpression` shows the L1 seeds used by the path.
+
+> You should see the same L1 seeds that you find from OMS.
+{: .checklist}
+
+### Inspecting a HLT configuration
+`hltGetConfiguration` is the official command to retrive a HLT configuration from the database.<br>
+> Since this involves connecting to the confdb database directly, this command should never be used in a large number of jobs or programatic loop. It should only be used interactively.
+{: .caution}
+~~~
+ssh -f -N -D 1080 <yourUserName>@lxplus.cern.ch 
+hltConfigFromDB --configName --adg /cdaq/physics/Run2016/25ns15e33/v4.2.3/HLT/V2 --dbproxy --dbproxyhost localhost --dbproxyport 1080 > dump_hlt_online_2016G.py
+~~~
+If you have connection issue, simply inspect one that has been downloaded for you
+~~~
+xrdcp root://cmseos.fnal.gov//store/user/cmsdas/2023/short_exercises/Trigger/dump_hlt_online_2016G.py .
+~~~
+Then, inspect the HLT configuration dump_hlt_online_2016G.py to look for the information about the L1 seed of the path into it:
+~~~
+grep 'process.HLT_PFMET170_HBHECleaned_v9' dump_hlt_online_2016G.py
+~~~
+You should see the expected output below:
+~~~
+process.HLT_PFMET170_HBHECleaned_v9 = cms.Path(process.HLTBeginSequence+process.hltL1sETM50ToETM120+process.hltPrePFMET170HBHECleaned+process.HLTRecoMETSequence+process.hltMET90+process.HLTHBHENoiseCleanerSequence+process.hltMetClean+process.hltMETClean80+process.HLTAK4PFJetsSequence+process.hltPFMETProducer+process.hltPFMET170+process.HLTEndSequence)
+~~~
+
+> ### Questions
+> To conclude, answer the following questions:
+> 
+> Which was the lowest threshold L1 seed active in the L1 menu?
+> Which is the lowest threshold L1 seed unprescaled?
+> How is it called the HLT module that contains the information about the L1 seeding?
+{: .challenge}
+

_episodes/04-HLT_efficiency.md

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+---
+title: "Measuring trigger efficiencies"
+teaching: 30
+exercises: 0
+objectives:
+- "Learn how to access the trigger information stored in MiniAOD and NanoAOD"
+- "Learn what is trigger objects and how to access them"
+- "Measure trigger efficiency using the tag-and-probe method"
+---
+
+> ## Prerequisites
+> Set up your machine following instructions in [setup][lesson-setup] first.
+{: .prereq}
+
+> ## Objective
+> The goal of the following exercises is to learn how to access and play with the trigger objects in our data and compute the efficiency of a specific HLT path and look also at its Level 1 (L1) seed. 
+>
+> The focus will be on a HLT path used during the 2016 data-taking to select events with a certain amount of missing transverse energy: `HLT_PFMET170_HBHECleaned_v*`.
+{: .objectives}
+
+## Compute a MET trigger efficiency
+
+We will first run this exercise on MiniAOD format, then run it again on NanoAOD.
+
+> ## MiniAOD
+> The MINIAOD format was introduced at the beginning of Run 2 to reduce the information and file size from the AOD file format.<br>
+> This means that several redundant versions of Ntuples for different analysis groups are stored in the limited CMS storage spaces.<br>
+> For Run 2 analyses, most of the analysis groups at CMS skimmed the centrally produced MiniAOD files into smaller, analysis-specific ROOT Ntuples.<br>
+
+MiniAOD events contain two trigger products that we will need in these exercises.<br>
+The `TriggerResults` product contains trigger bits for each HLT path, whereas the `TriggerObjectStandAlone` product contains the trigger objects used at HLT.<br>
+In addition, the trigger prescales, L1 trigger decisions, and L1 objects are stored in MiniAOD.<br>
+A more detailed description of the trigger-related MiniAOD event content can be found [here](https://twiki.cern.ch/twiki/bin/view/CMSPublic/WorkBookMiniAOD2016#Trigger).
+
+In this exercise we work with a skimmed MiniAOD file. (In case you are wondering where this skimmed file came from: it has been created using the configuration in `ShortExerciseTrigger/test/skim_pfmet100.py`, which selects events with offline MET above a threshold of 100 GeV.)
+
+> ### Inspect MiniAOD content
+> First, inspect the contents of the skimmed MiniAOD input file as follows:
+> ~~~
+> edmDumpEventContent root://cmseos.fnal.gov//store/user/cmsdas/2023/short_exercises/Trigger/skim_pfmet100_SingleElectron_2016G_ReReco_87k.root --regex=Trigger
+> ~~~
+> You can also inspect the full file content by dropping the --regex parameter.
+{: .challenge}
+
+As you see, there are indeed multiple TriggerResults products here, as well as other trigger-related collections.<br>
+We will learn how to interact with these two products and how to use their packed information in our physics analyses in this and the following exercises.
+
+{: .solution}
+
+> ## NanoAOD
+> A centrally maintained NanoAOD format was proposed in 2018, aiming for a common Ntuple format that can be used by most of the CMS analysis groups. 
+> Information about the NanoAOD format can be found [here](https://cms-nanoaod-integration.web.cern.ch/integration/master-102X/mc102X_doc.html#HLT). 
+{: .solution}
+
+{% include links.md %}
+