First measurement of the CP-violating phase ϕ s d d ¯ $$ {\phi}_s^{d\overline{d}} $$ in Bs0 → (K+π−)(K−π+) decays

First measurement of the CP-violating phase ϕ s d d ¯ $$ {\phi}_s^{d\overline{d}} $$ in Bs0 → (K+π−)(K−π+) decays