Embedding Example (VTX)


This page is work in progress and is designed to capture the details of the VTX analysis first performed by Takashi Hachiya. A repository has been created on GitHub in order to control the code changes - not as a replacement for CVS but as a temporary holding area:


The install process:

source /opt/phenix/bin/phenix_setup.csh -n new
make distclean
# Please set the "MYINSTALL" variable here, like in the Wiki link above...
/direct/phenix+u/mxmp/software/offline/analysis/dstmerge/autogen.sh --prefix=$MYINSTALL
make install

Slight variations of the above chain of commands tend to lead to some “libtool” error, this needs to be looked at.

VTX Embedding
The Improved Setup

Example layout of the “embed” folder (referred to in the variable $EMBEDDING_HOME which is set in the setup script)

drwxr-sr-x 3 mxmp rhphenix 4096 Jul 31 16:31 embed
drwxr-sr-x 3 mxmp rhphenix 4096 Jul 31 10:43 real
drwxr-sr-x 2 mxmp rhphenix 4096 Aug  5 20:57 setup
drwxr-sr-x 5 mxmp rhphenix 4096 Jul 30 19:59 sim

The “setup” folder is a new one (i.e. not present in the original code base and added for this study).

Embedding is a process with many moving parts and data elements. In order to facilitate this process, we have established an interim convention to try and keep things as transparent as possible:

Run the single particle simulation

Takashi’s working directory used as a starting point:


Under this directory, see the following 3 directories

Single Particle

The script ‘'’phparticlegen_pip_updated.csh’’’ serves to invoke ROOT:

root -b -q  'phparticlegen_pip.C(N, '$pid', "'"$outname"'")'

It has two input arguments at this point


Current version of the script:


Takes three arguments


Current version of the script:


Takes three arguments:

Make the data DST with raw detector hits

Takashi’s working directory used as a starting point:


The current version can be located under $EMBEDDING_HOME and is available on GitHub at the link above.

$EMBEDDING_HOME/dstmerge/wrk/submit/reco_rawhit_updated.csh is a script to run the reconstruction and save the raw hit in DST. Zvertex position is also limited with a certain range in the script to match the Z-vertex position between real and simulation.

The reconstruction macro (Fun4All_CA_merge.C) creates number of files which contain the reconstructed events for the specific trigger. One can see the trigger labels in the filename like MB (Minimum bias), ERT (EMCal-RICH Trigger), MU(Muon trigger), UP(Ultra-peripheral), OT(others). Example:


Which file is good for the embedding step depends on what the user want to do. The MB file is often used to mix an MB event and a single particle simualation for the efficiency study.

The next step is to run run_embed_updated.csh to mix the real data and simulation (see next section)


Starting point:


Current location of the script $EMBEDDING_HOME/embed/submit/run_embed_updated.csh. It is meant to merge the raw hit in real data and simulation, and to run the reconstruction using the merged hits.

run_embed_updated.csh <job_number> <event number> <input real DST> <input SIM DST> <output DST> <output ntuple> <output ntuple2>

Dependency: svx_cent_ana

Event Display