1. Visualization of embedding
Matevz Tadel,
CERN
Adam Kisiel,
Ohio State University

2. Outline Embedding process description Requirements
Proposition of features
Plans for implementation
Presentation of implemented features

3. Embedding goals
The final goal is to study and quantify the effects of resolution and efficiency by performing embedding in the real data
We need to make sure that the software tools to do that are available and ready.
We must test whether our software tools can do that without compromising quality and introducing artificial distortions in the studied quantities
Visualization is an important step to fulfill the goals

4. Embedding procedure OR Raw data background Monte-Carlo simulation
Raw data signal
ConvertRaw2SDigits
Simulation
ConvertRaw2SDigits
“Fake” SDigits
Simulated SDigits
“Fake” SDigits
Merge
Merge
Merge OR
Summed SDigits
Reconstruction
AliESD
Kinematics information
Effiency&Correction
Framework
High-level analysis code
Efficiency correction
Analysis results

5. Embedding status
Embedding has been tried and confirmed to work last year. Since then it has been a continuous effort to ensure it is kept in that state.
Most recent tests: last week, AliRoot v4-15-Rev-06 for central barrel detectors (ITS TPC TRD TOF).
Tested “real-life” scenario of embedding Pythia pp events into heavy-ion event background (Therminator PbPb midcentral events) as well as merging two pp events

6. Embedding visualization
For embedding visualization is an important tool; it helps in understanding the effects of merging two signals and should be helpful in debugging
Requirements for the visualization software are different from normal ones – the objective is to analyze the behavior of a rather small “signal” against an overall background
It is important to compare the “bare” and “embedded” signal reconstruction

7. Software requirements
The following “use cases” were considered when identifying tasks for embedding visualization
Looking for a low multiplicity signal in a high multiplicity background – visual highlighting should reflect the origin of the signal
Studying detector response – need to visually distinguish hits/digits/clusters from various sources as well as “merged” ones
Comparing “bare” and “embedded” signals requires simultaneous inspection of two or more events

8. Software tasks
The following software tasks for alieve were identified:
Possibility to load more than one event into alieve in such a way that each event is a separate object
Provide a way to show two events simultaneously “side-by-side” in a synchronized way
Visually differentiate hits/digits/clusters/tracks based on the event they come from
Visually differentiate hits/digits/clusters/tracks within a single event, based on the stream they come from
Highlight “merged” hits/digits/clusters/tracks

9. Two-event display requires patching ROOT and alieve two events
as separate
objects

10. Ideas for two-event display
Visually differentiate clusters/tracks from events
Test the display for large-multiplicity Pb-Pb event, to make sure that the “signal” is still visible – reduce the displayed information for the background only to the necessary
Provide a way to cut on the displayed data, to further reduce the amount of information: physics cuts and geometrical (acceptance) cuts
Show Kinematics/full information only for signal

11. Finding a needle in a haystack
embedded
signal
full PbPb event
only clusters
small marker

12. “Side-by-side” view mock-up

13. Ideas for the side-by-side view
Synchronize data highlighting and selection on both views
Lock the camera (zoom, rotation, shift) for both views so that actions in one view are automatically mirrored in the second
Second view may show either detector response from a specific stream or the input kinematic information for the “real” case of embedding model signal in real data event

14. Summary Embedding visualization is under way
Main software requirements identified
Specific software tasks for alieve defined
Implementation in alieve started
Example embedding events provided both for simple testing (pp) and full-scale testing (PbPb)

15. The End