The GAPS Project for Ultra-High Sensitivity Observation of Cosmic Ray Antiparticles in the Search for Dark Matter

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K14065
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Japan Aerospace EXploration Agency
• Principal Investigator: Masahiro Yamatani 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 招聘職員 (80896275)
• Project Period (FY): 2022-04-01 – 2024-03-31
• Keywords: 反重陽子

Outline of Final Research Achievements

We have significantly improved the understanding capability of cosmic ray antideuterons for the Antarctic balloon experiment GAPS. This progress was achieved by optimizing Boosted Decision Trees (BDT) and incorporating novel machine-learning methodologies, containing the augmentation of learning variables and the meticulous adjustment of learning parameters. Notably, this approach has demonstrated considerable usefulness in identifying antiprotons and antihelium. Furthermore, enhancements to the precision of velocity (β) reconstruction for low-energy antiparticles have effectively mitigated bias. Integrating features derived from Bragg curve fitting has also strengthened antideuterons' discrimination capability. Moreover, developing a machine learning framework has notably increased the efficiency of data analysis, concomitantly elevating both the celerity and accuracy of the analyses. These substantial strides represent a foundational achievement for prospective research endeavors.

Free Research Field

宇宙線物理実験

Academic Significance and Societal Importance of the Research Achievements

ダークマターは宇宙の質量の大部分を占めるとされながら、その正体は未解明であり、宇宙の根本的な理解を深める上で非常に重要な意義を持つ。そのような課題を解決するには、ダークマターが関わるエネルギーの大きさ、既知物質との相互作用などに関する多種多様な仮説に基づく観測手法を用いた、多角的なアプローチを取ることが求められる。本実験の宇宙線反重陽子を用いたダークマターの間接探索実験は、これまで確認されなかったエネルギー領域をターゲットにしており、ダークマター探索実験の中でも重要な位置を占める。またこの研究は先端技術の開発を促進し、計測技術やデータ解析技術の向上をもたらす。