GlueX Analysis Workshop 2013

Purpose

The purpose of this tutorial/workshop session will be to give an introduction to using the Hall-D analysis tools. It is open to anyone either inside or outside the GlueX collaboration who has an interest in doing physics inside Hall-D. The tutorial will cover the basics of:

• Physics Analysis Framework
• Using Boosted Decision Trees
• Amplitude Analysis using AMPtools

The tutorial will consist of a few talks with room for questions/discussion.

Location and Time

The tutorial will take place:

DATE: July. 10-11, 2013

TIME: 9:00am to 4:30pm EDT (i.e. JLab time).

LOCATION: CEBAF Center L102 - L104

Schedule Details (Work in Progress)

Overview (Matt)

• Talk (30 min): Physics Overview and Analysis Strategy
  • Define the physics goals
  • Discuss detector
  • Discuss general analysis strategy
• Talk (15 min): A specific physics example: γp→π⁺π⁺π^-n
• Exercise (15 min): Generate γp→π⁺π⁺π^-n with intermediate resonances

Monte Carlo Generators and Detector Simulation (Matt(/Paul?))

• Talk (? min): Other standard monte carlo tools
• Exercise (? min): Run HDGeant and mcsmear

JANA/DANA (Paul)

• Talk (35 mins): Intro to JANA/DANA (factories & plugins)
  • JANA is a framework: multithreaded, factory-based (describe concept of factories, tags (e.g. BCAL)), event-processors control the work flow
  • The primary executable (hd_root) does virtually nothing by itself, the processor in your plugin tells it what to do
  • JANA automatically loops over the events in your input files, executing the primary factory & plugin methods as needed: init(), brun(), evnt(), erun(), fini()
  • Track/Shower reconstruction, REST format, danarest plugin
  • Basic Analysis Classes: DKinematicData, DChargedTrackHypothesis, DChargedTrack, DNeutralShower, DMCThrown, DBeamPhoton
  • hd_dump: Prints data to screen
• Exercise (25 mins):
  • Use danarest plugin to do track reconstruction.
  • Print basic analysis objects (DMCThrown, etc.) to screen via hd_dump and inside of plugin
  • Stretch goal: figure out how to get the run number from inside the evnt() method and print it to screen for each event.

ANALYSIS Library (Paul)

Analysis Basics

• Talk (25 mins):
  • User specifies reaction & decay chain, library generates all particle combinations
  • Particle Combinations: Why, and why so many? (extra tracks, any PID of same q, decay products of different particles, beware double-counting), DParticleCombo contents
  • Basic example plugin: 3pi_n (go over line by line)
• Exercise (25 mins):
  • Generate 3pi_n plugin, manually histogram: #combos, #events with >= 1 combo, missing mass (calc manually), p-vs-theta & vertex-z for pi+'s and pi-'s

Kinematic Fitting

• Talk (30 mins):
  • What it is, how it works, constraints, how neutrals & magnetic field are handled
  • Setting it up automatically and manually (go over line-by-line)
• Exercise (30 mins):
  • Auto-kinematic fit 3pi_n, histogram kinematic fit confidence level, missing mass after kinematic fit (conlev > 1%)
  • Manually kinematic fit 3pi_n, including histograming confidence levels, missing mass after kinematic fit (conlev > 1%)
  • Stretch goal: histogram pi- px and vx pulls (conlev > 5%)

Analysis Details

• Talk (30 mins):
  • Thrown/Reconstructed track matching, PID FOM Calculation, new DTrackTimeBased for new PIDs (q+/q- subtlety), Event RF Bunch Selection
  • Kinematic Fitting
  • Different object versions (DParticleCombo, hypotheses)
• Exercise (25 mins):
  • Manually histogram: pid conlevs (dE/dx, timing, total)
  • Stretch goal: histogram pid confidence level vs. projected track start time for different PIDs for BCAL/TOF

Analysis Actions - Pre-existing

• Talk (25 mins):
  • Reaction-Independent (can be called manually): thrown, reconstructed track distros, gen-recon comparison (go over line-by-line on one)
  • Reaction-Dependent Histograms (executed for each combo): PID, kinfit results, missing mass, invariant mass (go over line-by-line on one)
  • Reaction-Dependent Cuts (executed for each combo): PID, kinfit conlev, missing mass, invariant mass (go over line-by-line on one)
  • #events/combos pass cuts histograms
• Exercise (25 mins):
  • Add reaction-independent analysis actions: fill histograms and look at kinematics in ROOT
  • Add reaction-dependent analysis actions: hist/cut pid, hist/cut kinematic fit results, hist missing mass before/after kinfit conlev cut

Analysis Actions - Custom

• Talk (10 mins):
  • Creating your own custom actions, remind to beware double-counting, warn about multi-threading issues
• Exercise (15 mins):
  • Generate custom action to make dalitz plot of 3 pions.

REST & ROOT

• Talk (25 mins):
  • REST Skims, TTree format, Making/Using a TSelector, beware double-counting when filling ROOT trees.
• Exercise (30 mins):
  • Create a skim of 3pi_n events, analyze the skim data, save the results to a root ttree, analyze the data in ROOT (make some plots)

Reactions with a Decay

• Talk
• Exercise (30 mins):
  • From scratch, make a plugin to analyze γp→η'p, η'→ηπ⁺π^-, η→γγ

Amplitude Analysis (Matt)

• Talk (45 mins): Amplitude Analysis Fitting Strategy
• Exercise (20 mins): performing a single fit and analyzing projections
• Talk (30 mins): Multiple fits, opportunities for extensions
• Exercise (20 mins): performing multiple fits in different bins of a mass spectrum