An Unsupervised Machine Learning Method for Electron--Proton Discrimination of the DAMPE Experiment

Abstract

Galactic cosmic rays are mostly made up of energetic nuclei, with less than $1\%$ of electrons (and positrons). Precise measurement of the electron and positron component requires a very efficient method to reject the nuclei background, mainly protons. In this work, we develop an unsupervised machine learning method to identify electrons and positrons from cosmic ray protons for the Dark Matter Particle Explorer (DAMPE) experiment. Compared with the supervised learning method used in the DAMPE experiment, this unsupervised method relies solely on real data except for the background estimation process. As a result, it could effectively reduce the uncertainties from simulations. For three energy ranges of electrons and positrons, 80--128 GeV, 350--700 GeV, and 2--5 TeV, the residual background fractions in the electron sample are found to be about (0.45 $\pm$ 0.02)$\%$, (0.52 $\pm$ 0.04)$\%$, and (10.55 $\pm$ 1.80)$\%$, and the background rejection power is about (6.21 $\pm$ 0.03) $\times$ $10^4$, (9.03 $\pm$ 0.05) $\times$ $10^4$, and (3.06 $\pm$ 0.32) $\times$ $10^4$, respectively. This method gives a higher background rejection power in all energy ranges than the traditional morphological parameterization method and reaches comparable background rejection performance compared with supervised machine learning~methods.

arXiv comment10 pages, 5 figures, 1 table

References in corpus (20)

• Particle Dark Matter: Evidence, Candidates and Constraints
• Dark Matter Candidates from Particle Physics and Methods of Detection
• The energy spectrum of cosmic-ray electrons at TeV energies
• Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons
• Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S
• The DArk Matter Particle Explorer mission
• Measurement of the cosmic-ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite
• Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope
• Measurement of the cosmic ray helium energy spectrum from 70 GeV to 80 TeV with the DAMPE space mission
• Energy Spectrum of Cosmic-ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station
• The Plastic Scintillator Detector at DAMPE
• The on-orbit calibration of DArk Matter Particle Explorer
• Charge Measurement of Cosmic Ray Nuclei with the Plastic Scintillator Detector of DAMPE
• Search for gamma-ray spectral lines with the DArk Matter Particle Explorer
• Dark Matter Particle Explorer observations of high-energy cosmic ray electrons plus positrons and their physical implications
• A Parameterized Energy Correction Method for Electromagnetic Showers in BGO-ECAL of DAMPE
• Observations of Forbush Decreases of cosmic ray electrons and positrons with the Dark Matter Particle Explorer
• In-flight performance of the DAMPE silicon tracker
• A neural network classifier for electron identification on the DAMPE experiment
• Introduction to Principal Components Analysis

Cited by in corpus (2)

• Simulation study of performance of the Very Large Area gamma-ray Space Telescope
• Energy Reconstruction of Non-fiducial Electron-Positron Events in the DAMPE Experiment Using Convolutional Neural Networks