August 2025

Journal

Antihelium-3 sensitivity for the GRAMS experiment

By:
Zeng, J; Aramaki, Tsuguo; Aoyama, K; Arai, S; Arai, S; Asaadi, Jonathan; Bamba, A; Cannady, N; Coppi, P; De Nolfo, G; Errando, M; Fabris, Lorenzo ; Fujiwara, T; Fukazawa, Yasushi; Ghosh, P; Hagino, K; Hakamata, T; Hiroshima, N; Ichihashi, M; Ichinohe, Y; Inoue, Y; Ishikawa, K; Ishiwata, K; Iwata, T; Karagiorgi, G; Kato, T.; Kawamura, H; Khangulyan, D; Krizmanic, J; LeyVa, J; Malige, A; Mitchell, J; Mitchell, J; Mukherjee, R; Nakajima, R; Nakazawa, K; Odaka, H; Okuma, K; Perez, Kerstin; Poudyal, Nabin; Safa, I; Sakai, K; Sasaki, M; Seligman, W; Sensenig, J; Shirahama, K; Shiraishi, T; Smith, S; Suda, Yusuke; Suraj, Arathi; Takahashi, H; Takashima, S; Tamba, T; Tanaka, M; Tandon, S; Tatsumi, R; Tomsick, J; Tsuji, N; Uchida, Y; Utsumi, Y; Watanabe, S; Yano, Y; Yawata, K; Yoneda, H; Yorita, K; Yoshimoto, M
Journal Name:
Astroparticle Physics
Page Number:
103152-103160
Volume:
173
Publication Date:
August 2025
View DOI Listing:
https://doi.org/10.1016/j.astropartphys.2025.103152

Abstract

The Gamma-Ray and AntiMatter Survey (GRAMS) is a next-generation balloon/satellite mission utilizing a Liquid Argon Time Projection Chamber (LArTPC) detector to measure both MeV gamma rays and antinuclei produced by dark matter annihilation or decay. The GRAMS can identify antihelium-3 events based on the measurements of X-rays and charged pions from the decay of the exotic atoms, Time of Flight (TOF), energy deposition, and stopping range. This paper shows the antihelium-3 sensitivity estimation using a GEANT4 Monte Carlo simulation. For the proposed long-duration balloon (LDB) flight program (35 days x 3 flights) and future satellite mission (2-year observation/10-year observation), the sensitivities become 1.47 × 10−7 [m2 s sr GeV/n]−1 and 1.55 × 10−9 [m2 s sr GeV/n]−1/3.10 x 10-10 [m2 s sr GeV/n]−1, respectively. The results indicate that GRAMS can extensively investigate various dark matter models through the antihelium-3 measurements.

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