Preface/Requirements
*************************

This tutorial aims to demonstrate, how simulation and analysis can be performed with the PandaRoot framework. The example channel is

**p pbar ->  J/psi (-> mu+mu-) pi+ pi-**

The analysis part will cover

   * Data access
   * Particle Identification
   * Combinatorics
   * MC truth match
   * Fitting with 4 constraint (4C), vertex constraint, mass constraint

The tutorial is based on **trunk** and is meant to be an all time running tutorial. All macros and necessary files can be found under **tutorials/rho** and **macros/master**. Last test of this tutorial was done **Mar. 2022**.

Installation of PandaRoot
===========================

In order to install PandaRoot and the external packages, please follow the instructions under https://git.panda.gsi.de/PandaRootGroup/PandaRoot/-/tree/dev/docs/Installation. After installation of the libraries, you can create a folder in an arbitrary place and copy all files from ``tutorials/rho`` to this place.

General Documentation of Rho classes
======================================

There is a wiki page available under which more **detailled information about the Rho classes** is available. Please follow https://panda-wiki.gsi.de/foswiki/bin/view/Computing/PandaRootAnalysisJuly13

Files in directory tutorials/rho
==================================
All things we are going to use and run are located in the directory **tutorials/rho**.

You'll find the following files in this directory:

   * for event generation
      * ``pp_jpsi2pi_jpsi_mumu.dec`` - decay file specifying the signal decay channel

   * for running the simulation, digitization, reconstruction, and PID
      * ``tut_sim.C`` - Simulation (transport) of the generated events
      * ``tut_aod.C`` - Digitization, reconstruction and pid assignment of simulated data; this is the analysis-objects-data level (AOD).
      * ``tut_runall.sh`` - Shortcut shell script to run the two macros above for sim/digi/reco/pid macros
      * ``tut_fastsim.C`` - Run fast simulation (this skips the Geant based detailed simulation and transport, but only does smearing and acceptance cuts).
      * ``qfsana.C`` - Does fast simulation and analysis in one simple step

   * for analysis
      * ``auxtut.C`` - Some auxilliary functions for analysis
      * ``tut_ana_comb.C`` - Basic combinatorics
      * ``tut_ana_pid.C`` - Particle identification (PID)
      * ``tut_ana_mcmatch.C`` - Monte carlo truth match
      * ``tut_ana_mclist.C`` - Monte carlo truth list access
      * ``tut_ana_fit.C`` - Kinematic/vertex fitting
      * ``tut_ana.C`` - Combinatorics, PID, MC truth match and fitting all together
      * ``tut_ana_ntp.C`` - Example for using ntuple for analysis
      * ``tut_ana_fast.C`` - Does the complete analysis on the fast simulation output
      * ``qana.C`` - Simple one line macro call for a complete ntuple analysis.
      * ``tut_makegifs.C(_file_, _type_)`` - simple macro producing images with ending _type_ ("gif", "pdf", "png",...) from all histograms in _file_

   * for running analysis in a !FairTask
      * ``PndTutAnaTask.h`` - Header file of the analysis class
      * ``PndTutAnaTask.cxx`` - Source file of the analysis class
      * ``CMakeLists.txt`` - necessary to build library
      * ``tutrhoLinkDef.h`` - necessary to build library
      * ``tut_ana_task.C`` - Macro to run the analysis task
      *