The particle surface of spinning test particlesYong Song, Yiting Cen, Leilei Tang, Jiabao Hu, Kai Diao, Xiaofeng Zhao and Shunping ShiEur. Phys. J. C, 83 9 (2023) 833DOI: https://doi.org/10.1140/epjc/s10052-023-11970-5