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[WIP] Comments received during lesson #30

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[WIP] Comments received during lesson #30

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9c10d41
Update HLT intro lesson.
May 18, 2016
19b6552
Merge from upstream.
roelaaij May 19, 2016
e185e76
Fix trigger line name for Run 2.
roelaaij May 19, 2016
c6ab43e
Update title and length.
roelaaij May 19, 2016
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16 changes: 8 additions & 8 deletions 18-hlt-intro.md
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Original file line number Diff line number Diff line change
@@ -1,8 +1,8 @@
---
layout: page
title: First steps in LHCb
title: Second steps in LHCb
subtitle: HLT intro
minutes: 45
minutes: 75
---

> ## Learning Objectives {.objectives}
Expand Down Expand Up @@ -43,16 +43,16 @@ available in HLT2 is the same as the offline reconstruction, physics analysis
can be done with the candidates created in HLT2. If a line is configured to be a
Turbo line, all information on the candidates that it selects is stored in the
raw event. These candidates can be resurrected later by the Tesla application and
written to a microDST. This is similar to stripping streams that go to
microDST, where only candidates that are used in passing selections are
available to analysts. The Turbo stream is different because information that
written to a microDST. This is similar to stripping streams that go to
microDST, where only candidates that are used in passing selections are
available to analysts. The Turbo stream is different because information that
is not saved is lost forever.

We will now have a look at some of the candidates stored by the HLT. We will use the script we
[used last time](http://lhcb.github.io/first-analysis-steps/05-interactive-dst.html)
as a starting point, and the file
`root://eoslhcb.cern.ch//eos/lhcb/user/r/raaij/Impactkit/00051318_00000509_1.turbo.mdst`.
This file contains some 2016 Turbo events from [run
This file contains some 2016 Turbo events from [run
174252](http://lbrundb.cern.ch/rundb/run/174252/). Fire up your
favourite editor, open the script and save a copy to work on as
`hlt_info.py`. There are a few things in the script that we don't need and can
Expand All @@ -75,15 +75,15 @@ decision. This can be done using the `decision` member function of a

~~~ {.python}
reports = evt['Hlt1/DecReports']
report = reports.decReport('Hlt1TrackAllL0Decision')
report = reports.decReport('Hlt1TrackMVADecision')
print report.decision()
~~~

The HLT1 selections that are most efficient for hadronic charm and beauty decays
in Run 2 are called Hlt1TrackMVA and Hlt1TwoTrackMVA. Use the advance function
to find an event that was accepted by either of these trigger selections.

The DecReports only contains the decisions for each line, 1 or 0. The
The DecReports only contains the decisions for each line, 1 or 0. The
candidates themselves are stored in the
SelReports ("Hlt{1,2}/SelReports"). Get the HLT1 SelReports from the event store
and retrieve the one for one of the TrackMVA selections using the selReport function,
Expand Down