TrkAna

Overview

TrkAna is a track-based ROOT TTree that can be used to help with analysis. Each entry in the TTree corresponds to a single fitted track and contains reconstructed information from the tracker, calorimeter and CRV. There is also the option to write out Monte Carlo truth information and additional information for other track types that might be important to an analysis.

How to Get Help

Feel free to send any questions to the #trkana Slack channel, or the 'Is It Me Or A Bug?' hypernews forum.

There is also a tutorial that is a few years old and will be updated soon.

For Analyzers

How To Create a TrkAna Tree

You can use the TrkAna Musing like so:

setup mu2e
muse setup TrkAna
mu2e -c TrkAna/fcl/TrkAnaReco.fcl -s mcs.art --TFileName trkana.root

where mcs.art contains the result of the Mu2e reconstruction.

In the trkana.root file, you will see two different TrkAna-related folders:

• TrkAnaNeg contains the results of the negatively-charged tracks, and
• TrkAnaPos contains the results of the positively-charged tracks.

TrkAna is designed to be flexibile so if this does not produce the type of tree you want, then there are fcl parameters that can be changed. A few examples are available here: https://github.com/Mu2e/TrkAna/tree/main/fcl and are given in the table below. Also, you can always ask for help on the #trkana channel on Slack

fcl file	module label	candidate	supplements	notes
TrkAnaReco.fcl	TrkAnaNeg	downstream e-minus	upstream e-minus, downstream mu-minus
	TrkAnaPos	downstream e-plus	upstream e-plus, downstream mu-plus
CrvExpert.fcl	TrkAnaNeg	downstream e-minus	upstream e-minus, downstream mu-minus	adds crvinfo, crvinfomc, crvsummary, crvsummarymc, and crvinfomcplane branches
	TrkAnaPos	downstream e-plus	upstream e-plus, downstream mu-plus
TrkAnaReco_Upstream.fcl	TrkAnaNeg	upstream e-minus	downstream e-minus, upstream mu-minus
	TrkAnaPos	upstream e-plus	downstream e-plus, upstream mu-plus
TrkAnaReco_ceSimReco.fcl	TrkAnaNeg	downstream e-minus	none	for use with reco files generated with ceSimReco.fcl
fcl files below are flagged for updating / removal
TrkAnaRecoEnsemble-MC.fcl	TrkAnaNeg	downstream e-minus	upstream e-minus, downstream mu-minus	for use with MDC2018 Ensemble datasets
	TrkAnaPos	downstream e-plus	upstream e-plus, downstream mu-plus
TrkAnaRecoEnsemble-Data.fcl	TrkAnaNeg	downstream e-minus	upstream e-minus, downstream mu-minus	for use with MDC2018 Ensemble datasets, no MC information
	TrkAnaPos	downstream e-plus	upstream e-plus, downstream mu-plus
TrkAnaReco_wTrkQualFilter.fcl	TrkAnaNeg	downstream e-minus	upstream e-minus, downstream mu-minus	an art filter module is run before creating the TrkAna tree
	TrkAnaPos	downstream e-plus	upstream e-plus, downstream mu-plus
TrkAnaReco_MultipleTrkQual.fcl	TrkAnaNeg	downstream e-minus	upstream e-minus, downstream mu-minus	an additional TrkQual algorithm is used for each track
	TrkAnaPos	downstream e-plus	upstream e-plus, downstream mu-plus

How to Analyze a TrkAna Tree

Each of these contain TTrees that you can use ROOT or python

with ROOT

You can use the trkana tree like you would any other ROOT TTree: with the ROOT command line for data exploration, with ROOT macros to make plots etc.

with Python

• Note: the below is for the latest version of uproot4

The best way to open ROOT files in Python is to use the uproot package. It does not require a working installation of ROOT, so it allows to read a ROOT file on basically any platform that supports Python (e.g. Colaboratory). It also provides a more pythonic bridge between ROOT and Numpy/pandas.

In order to open a ROOT TTree with uproot it's sufficient to write:

import uproot
trkananeg = uproot.open("trkana.root:TrkAnaNeg/trkana") # opens the 'trkana' tree in the 'TrkAnaNeg' folder

Now, if we want to store, for example, the deent branch in the dataframe:

df = tree.arrays(filter_name=['deent*'],library="pd")

Once your data is stored in a pandas dataframe or in a numpy array you can plot it with the many plotting libraries available (matplotlib, plot.ly, etc.). This example shows how to plot an histogram with matplotlib:

import uproot
import matplotlib.pyplot as plt

trkananeg = uproot.open("trkana.root:TrkAnaNeg/trkana")
df = trkananeg(filter_name=['deent*'],library="pd")
plt.hist(df["deent.mom"], bins=60, range=(95,110))

A class that allows you to query the dataframe and plot manipulated variables can be found at https://github.com/soleti/mu2e_plotter.

For Developers

If you will be contributing to the development of TrkAna, then you can fork TrkAna on GitHub and build it within Muse Like so:

Once you log in:

setup mu2e
cd /your/working/directory
git clone git@github.com:<Your GitHub Username>/Offline.git (or muse backing Offline vXX_YY_ZZ)
git clone git@github.com:<Your GitHub Username>/TrkAna.git
muse setup
muse build -j4 --mu2eCompactPrint

Then you can make your developments and put in a pull request.

Version History / TrkAna Musings

This is the list of TrkAna Musings. The top row corresponds to the "current" version.

TrkAna Musing	TrkAna tag	muse backings	muse stub	notes
(not built)	v03_00_01	N/A	N/A	tag before major breaking change, just code tidying so no associated musing
v03_00_00	v03_00_00	SimJob MDC2020y --> Offline v10_22_01	sl7-prof-e20-p040	breaking changes: branch names now three characters; uses KinKal fits
v02_03_00	v02_03_00	SimJob MDC2020w --> Offline v10_21_00	sl7-prof-e20-p039
v02_02_00	v02_02_00	SimJob MDC2020v --> Offline v10_20_00	sl7-prof-e20-p035
v02_01_00	v02_01_00	SimJob MDC2020u --> Production v00_10_00 --> Offline v10_18_00	sl7-prof-e20-p033
v02_00_01	v02_00_01	SimJob MDC2020t --> Production v00_09_11 --> Offline v10_17_00	sl7-prof-e20-p026
(not built)	v02_00_00	N/A	N/A	failed build due to incompatible KinKal version
v01_01_00	v01_01_00	SimJob MDC2020r --> Production v00_09_02 --> Offline v10_15_01	sl7-prof-e20-p023	adds TrkAnaUtils
(not built)	v01_00_01	N/A	N/A	resolves MDC2020r incompatibility
v01_00_00a	v01_00_00	Production v00_07_00 --> Offline v10_11_00	sl7-prof-e20-p021	updated for muse 1-path/2-path change
v01_00_00	v01_00_00	Production v00_06_00 --> Offline v10_10_01	sl7-prof-e20-p018	uses deprecated "muse link"

Tree Structure

The TrkAna tree structure is documented in google sheet (spreadsheet). There are separate sheets for different major version numbers. Links to the existing sheets are below. These are viewable by anyone; if you would like to comment or edit these sheets please send a message to the #TrkAna slack channel. Note that the sheets have multiple tabs, at the bottom of the page. The main tab lists the branches, while the other tabs list the detailed content (leafs) of the individual branches, by name.

• Version 4 Branch Documentation
• Version 3 Branch Documentation

Hit Level Information

By setting the diagLevel to 2 when running TrkAna, you will fill hit level information branches. If you are processing Monte Carlo information, hit level Monte Carlo truth branches will also be added. Adding these increases the size of the output file by an order of magnitude.

Future Developments

We're always looking for input from developers and analyzers to keep TrkAna up-to-date! Get in touch on the #trkana Slack channel, or with Andy Edmonds directly with any thoughts / comments you have