codeHF

HF tasks and tests

HF decay reconstruction tasks

The prepared HF example allows you to run reconstruction of 2-prong secondary vertices and a simple analysis of D⁰ mesons. The entire data processing procedure in O² involves several steps:

1. Pre-selection of secondary tracks
   • Performed by the trackIndexSkimCreator class in the o2-analysis-hf-track-index-skim-creator binary.
   • Includes track selection, candidate preselection, and secondary vertex reconstruction.
2. Reconstruction of 2-prong decay candidates
   • Performed by the candidateCreator2Prong class in the o2-analysis-hf-candidate-creator-2prong binary.
   • Reconstructs the secondary vertices again and creates 2-prong decay candidates.
   • Performs MC matching of the reconstructed candidates and of the generated particles.
3. Final selection of candidates
   • Performed by the candidateSelectorD0 class in the o2-analysis-hf-candidate-selector-d0 binary.
   • Appplies cuts on the parameters of the decay topology and track PID cuts.
4. D⁰ analysis task
   • Performed by the taskD0 class in the o2-analysis-hf-task-d0 binary.
   • Fills histograms with kinematic properties of selected candidates (and matched particles).

Check this presentation to learn more about the design of the underlying data processing scheme that includes skimming, decay reconstruction and analysis.

Validation

See the README in the main repository directory to get familiar with the validation framework.

The default example in the HF validation code performs the D⁰ reconstruction analysis using AliPhysics (Run 1+2) and O² (Run 3) and produces comparison plots for various decay parameter distributions.

The validation steps are defined in the task configuration script config_tasks.sh.

Select your data

In order to run the analysis with AliPhysics, you need AliESDs.root files and specify their location by setting the variables INPUT_DIR and INPUT_FILES in your input specification script. To process Monte Carlo data, you also need the corresponding galice.root and Kinematics.root files.

The default HF input specification script config_input.sh contains some predefined input cases with hard-coded paths. By default INPUT_CASE=2 is selected. To run the code with the same input files locally on your machine, download them from the Grid directory /alice/sim/2018/LHC18a4a2_cent/282099/001/. You can use the download_from_grid.sh script for that.

Run the example

Enter the codeHF directory and execute the steering script:

bash runtest.sh

Running all the steps with INPUT_CASE=2 takes about 40 seconds in total.

The postprocessing step produces several plots comparison_histos_(...).pdf, MC_(...).pdf.

To confirm that the output of the default settings looks as expected, compare the produced plots with their reference counterparts (...)_ref.pdf.

The complete list of commit hashes used to produce the reference plots can be found in versions_ref.txt.