Table 1 The measured charge q$_{d}$ , mass m$_{d}$ ( m$_{d}$ ) ( GeV ) and events for the channel ψ (2 S ) → ddJ/ψ Table 2 The measured charge q$_{u}$ , mass m$_{u}$ ( m$_{u}$ ) ( GeV ) and events for the channel ψ (2 S ) → uuJ/ψ containing this kind of tracks will not satisfy the conservation law, which can help find frac- tional charge particles described by the two parameters ( q, m$_{f}$ ) by analyzing each exclusive channel. Between the two parameters, q is more sensitive than m$_{f}$ . Whether the distribution of m$_{f}$ concentrates at one or more points very well depends on the momentum resolution for charged tracks and the energy resolution for neutral tracks. The effect of | 1 /q − 1 | on the momentum for charged tracks is much larger than the resolutions. Let q = 2 / 3, then | 1 /q − 1 | is 50%, while the momentum resolution is 0 . 5% for charged tracks and 2 . 5% for neutral tracks for BESIII $^{[11]}$. The larger | 1 /q − 1 | is, the more sensitive the method is to search for the fractional charge particles, especially for the type of ff . Another advantage of the method is independence of any theory models. Even if fractional charge particles carry continuum masses, the method can be used to search for them, while the dE/dx ionization energy loss method is not adequate. [1] Phys. Lett. 8 (1964) 214, M. Gell-Mann. CERN Reports TH401, TH412 (1964), G. Zweig. 7 input mass m$_{u}$ 0.005 0.025 0.045 0.065 0.085 output mass m 2 u 0 . 016 2 ± 0 . 031 2 0 . 033 2 ± 0 . 029 2 0 . 044 2 ± 0 . 031 2 0 . 064 2 ± 0 . 029 2 0 . 072 2 ± 0 . 024 2 charge q$_{u}$ 0 . 635 ± 0 . 006 0 . 662 ± 0 . 005 0 . 660 ± 0 . 004 0 . 654 ± 0 . 009 0 . 659 ± 0 . 004 events 28 24 33 32 27 input mass m$_{d}$ 0.005 0.025 0.045 0.065 0.085 output mass m 2 d 0 . 010 2 ± 0 . 026 2 0 . 022 2 ± 0 . 026 2 0 . 037 2 ± 0 . 031 2 0 . 053 2 ± 0 . 026 2 0 . 078 2 ± 0 . 029 2 charge q$_{d}$ 0 . 339 ± 0 . 003 0 . 333 ± 0 . 002 0 . 333 ± 0 . 003 0 . 329 ± 0 . 003 0 . 323 ± 0 . 002 events 36 45 38 32 38