Yunbai Dong's research was supported in part by the NSFC (11671314) and the Foundation of Hubei Provincial Department of Education (Q20161602). Bentuo Zheng's research was supported in part by the NSF
In this paper, we introduce a new geometric constant CNJ(P)(a, X) of a Banachspace X, which is closely related to the generalized von Neumann-Jordan constant and an