Examples of basic analysis techniques for neutral meson and photon data from the PHENIX detector
David, Gabor
;
Potekhin, Maxim
;
PHENIX collaboration
Cite as: David, Gabor; Potekhin, Maxim; PHENIX collaboration (2021). Examples of basic analysis techniques for neutral meson and photon data from the PHENIX detector. CERN Open Data Portal. DOI:10.7483/OPENDATA.PHENIX.70SC.C9E7
Data recorded in 2015 and published in 2021Dataset Derived PHENIX BNL-RHIC
Description
This record contains datasets from the Electromagnetic Calorimeter (EMCal) of the PHENIX detector. It aims to present a few basic techniques of identifying π0-s and photons using that device. The data is provided in the form of ROOT files containing small samples (Ntuples) of reconstructed p+Au data taken with the PHENIX detector in 2015 at √sNN=200 GeV. The Gamma-Gamma Ntuples (ggntuple) and Single Cluster Ntuples (gnt) are provided. Both minimum bias and EMCal-triggered data are included. These samples were created for educational and training purposes only and are not at all usable for deriving any real physics results. An example code working with the data is attached as ROOT macros. A detailed guide is also provided.
Dataset characteristics
1255308 events. 9 files. 70.3 MiB in total.Dataset semantics
| Variable | Type | Description |
|---|---|---|
| cent | float | Event centrality |
| vtxZ | float | z-vertex of the event |
| pt | float | Transverse momentum of cluster pair (π0 candidate) for ggntuple; Transverse momentum of the cluster (γ-candidate) for gnt |
| costheta | float | cos of the opening angle between the two clusters for ggntuple; Polar angle of the cluster (γ-candidate) for gnt |
| phi | float | Azimuthal angle of the direction of the pair momentum (assumed π0) for ggntuple; Azimuthal angle of the cluster (γ-candidate) for gnt |
| mass | float | Invariant mass calculated from the two clusters (energy and position) |
| asym | float | Energy asymmetry (|E1−E2|/(E1+E2)) of the two clusters |
| sec1 | float | EMCal sector where the first cluster is |
| Ecore1 | float | “Core” energy of the first cluster |
| tof1 | float | Time-of-flight of the first cluster |
| twrhit1 | float | Number of towers in the first cluster |
| prob1 | float | Probability that the first cluster is a photon (based on χ2) |
| chisq1 | float | χ2 from expected photon shape for the first cluster |
| stoch1 | float | Combined variable to describe “photonness” of first cluster |
| sec2 | float | EMCal sector where the second cluster is |
| Ecore2 | float | “Core” energy of the second cluster |
| tof2 | float | Time-of-flight of the second cluster |
| twrhit2 | float | Number of towers in the second cluster |
| prob2 | float | Probability that the second cluster is a photon (based on χ2) |
| chisq2 | float | χ2 from expected photon shape for the second cluster |
| stoch2 | float | Combined variable to describe “photonness” of second cluster |
| sec | float | EMCal sector of the cluster (γ-candidate) |
| ecore | float | “Core” energy of the cluster (γ-candidate) |
| ecent | float | Energy in the central tower of the cluster (γ-candidate) |
| tof | float | Time-of-flight in the central tower of the cluster (γ-candidate) |
| prob | float | Probability that the cluster is a photon (based on χ2) |
| disp | float | Dispersion of the cluster (γ-candidate) |
| chisq | float | χ2 from expected photon shape of the cluster (γ-candidate) |
| twrhit | float | Number of towers in the cluster (γ-candidate) |
| stoch | float | Combined variable to describe “photonness” of the cluster (γ-candidate) |
| x | float | x-position of impact point on the EMCal surface |
| y | float | y-position of impact point on the EMCal surface |
| z | float | z-position of impact point on the EMCal surface |
How can you use these data?
See the attached PDF guide and the example ROOT macros illustrating how to work with the data.
Files and indexes
Disclaimer
These open data are released under the Creative Commons Zero v1.0 Universal license.
Neither the experiment(s) ( PHENIX ) nor CERN endorse any works, scientific or otherwise, produced using these data.
This release has a unique DOI that you are requested to cite in any applications or publications.
