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Search for Light-Mass Fractionally Charged Particles in Space with DAMPE Experiment

F. Alemanno, Q. An, P. Azzarello, F. C. T. Barbato, P. Bernardini, X. J. Bi, H. V. Boutin, I. Cagnoli, M. S. Cai, E. Casilli, J. Chang, D. Y. Chen, J. L. Chen, Z. F. Chen, Z. X. Chen, P. Coppin, M. Y. Cui, T. S. Cui, I. De Mitri, F. de Palma, A. Di Giovanni, T. K. Dong, Z. X. Dong, G. Donvito, J. L. Duan, K. K. Duan, R. R. Fan, Y. Z. Fan, F. Fang, K. Fang, C. Q. Feng, L. Feng, S. Fogliacco, J. M. Frieden, P. Fusco, M. Gao, F. Gargano, E. Ghose, K. Gong, Y. Z. Gong, D. Y. Guo, J. H. Guo, S. X. Han, Y. M. Hu, G. S. Huang, X. Y. Huang, Y. Y. Huang, M. Ionica, L. Y. Jiang, W. Jiang, Y. Z. Jiang, J. Kong, A. Kotenko, D. Kyratzis, S. J. Lei, B. Li, M. B. Li, W. L. Li, W. H. Li, X. Li, X. Q. Li, Y. M. Liang, C. M. Liu, H. Liu, J. Liu, S. B. Liu, Y. Liu, F. Loparco, M. Ma, P. X. Ma, T. Ma, X. Y. Ma, G. Marsella, M. N. Mazziotta, D. Mo, Y. Nie, X. Y. Niu, A. Parenti, W. X. Peng, X. Y. Peng, C. Perrina, E. Putti Garcia, R. Qiao, J. N. Rao, Y. Rong, A. Serpolla, R. Sarkar, P. Savina, Z. Shangguan, W. H. Shen, Z. Q. Shen, Z. T. Shen, L. Silveri, J. X. Song, H. Su, M. Su, H. R. Sun, Z. Y. Sun, A. Surdo, X. J. Teng, A. Tykhonov, G. F. Wang, J. Z. Wang, L. G. Wang, S. Wang, X. L. Wang, Y. F. Wang, D. M. Wei, J. J. Wei, Y. F. Wei, D. Wu, J. Wu, S. S. Wu, X. Wu, Z. Q. Xia, Z. Xiong, E. H. Xu, H. T. Xu, J. Xu, Z. H. Xu, Z. Z. Xu, Z. L. Xu, G. F. Xue, M. Y. Yan, H. B. Yang, P. Yang, Y. Q. Yang, H. J. Yao, Y. H. Yu, Q. Yuan, C. Yue, J. J. Zang, S. X. Zhang, W. Z. Zhang, Y. Zhang, Y. P. Zhang, Y. Zhang, Y. J. Zhang, Y. Q. Zhang, Y. L. Zhang, Z. Zhang, Z. Y. Zhang, C. Zhao, H. Y. Zhao, X. F. Zhao, C. Y. Zhou, X. Zhu, Y. Zhu

Abstract

Free Fractionally Charged Particles (FCPs) are predicted by some theories beyond or extended to the standard model. FCPs have been widely searched for by underground and space-based experiments based on the assumption of heavy lepton-like particles. However, there is a paucity of research focusing on light-mass FCPs (LFCPs) in the sub-MeV mass range. In this work, we report the LFCPs in primary high energy cosmic rays, based on observational data from the Dark Matter Particle Explorer (DAMPE) satellite. This study utilized ten years on-orbit data of DAMPE to search for LFCPs with a charge of $\frac{2}{3}~e$. No LFCP candidate was observed. Upper flux limit of LFCPs with a mass of 0.511 MeV$/c^{2}$ and a charge of $\frac{2}{3}~e$ is determined to be $\rm 5.0 \times 10^{-11}\,cm^{-2}sr^{-1}s^{-1}$ at the $\rm 90\%$ confidence level.

Search for Light-Mass Fractionally Charged Particles in Space with DAMPE Experiment

Abstract

Free Fractionally Charged Particles (FCPs) are predicted by some theories beyond or extended to the standard model. FCPs have been widely searched for by underground and space-based experiments based on the assumption of heavy lepton-like particles. However, there is a paucity of research focusing on light-mass FCPs (LFCPs) in the sub-MeV mass range. In this work, we report the LFCPs in primary high energy cosmic rays, based on observational data from the Dark Matter Particle Explorer (DAMPE) satellite. This study utilized ten years on-orbit data of DAMPE to search for LFCPs with a charge of . No LFCP candidate was observed. Upper flux limit of LFCPs with a mass of 0.511 MeV and a charge of is determined to be at the confidence level.
Paper Structure (2 equations, 4 figures)

This paper contains 2 equations, 4 figures.

Figures (4)

  • Figure 1: The distributions of charges measured by the PSD (a) and STK (b). A Landau-Gaussian convoluted function was used to fit the on-orbit data (black points), MC electrons (blue line) , and MC LFCPs (green line) separately.
  • Figure 2: Fig.2(a) and Fig.2(b) depict the discrimination of MC LFCPs signals and electron backgrounds in the PSD and STK detectors, respectively. The blue lines depict the backgrounds of MC electrons, and the green lines represent the possible distributions of LFCPs signals. The pink integration curves representing the cumulative distributions from the MC LFCPs. The borders were evaluated as $0.73\,e$ for PSD and $0.78\,e$ for STK, with the efficiencies of 72.4% and 93.2%, respectively. The two-dimensional charge distributions of PSD-STK for MC LFCPs and MC electrons are shown in Fig.2(c) and Fig.2(d), respectively, with the signal region applied and shown as the red lines. The electrons sample is considered as the main background and away from the signal region. The signal region contains 67.4% of the MC LFCPs signals.
  • Figure 3: The two dimensional charge distribution of PSD-STK of on-orbit data. The lines define the signal region for LFCP.
  • Figure 4: Flux upper limits for LFCP with a mass range from 0.2 to 1 MeV$/c^{2}$.