IV.R407 — OQ-CKM1 Status after Sprint 5C: rho_bar Derived, A Improved, eta_bar Open

OQ-CKM1 (Wolfenstein CP parameters from tau) status after Sprint 5C: (1) rho_bar = 1/(2*pi) at +974.5 ppm -- TAU-EFFECTIVE (IV.T164). (2) A = 1-(3/2)*iota_tau^2 at -887.3 ppm -- TAU-EFFECTIVE (IV.T165), improved from -17433 ppm. (3) eta_bar: best sqrt(5)/(2*pi) at +22647 ppm -- CONJECTURAL (IV.P197), no tau-effective formula found. (4) Lambda_C: already tau-effective at -2327 ppm (IV.T152). Two of four Wolfenstein parameters are now tau-effective. eta_bar remains the main open question.