unitaritytriangle
Unitarity triangle is a triangle in the complex plane that encodes the unitarity of the Cabibbo–Kobayashi–Maskawa (CKM) matrix, the quark mixing matrix in the Standard Model. Because the CKM matrix is unitary, certain sums of products of its elements must vanish. The most studied case is the bd unitarity triangle, derived from the relation Vud Vub* + Vcd Vcb* + Vtd Vtb* = 0. Interpreted as vectors in the complex plane, these three terms form the sides of a closed triangle. In the Wolfenstein parametrization the apex of this triangle—the point where the second and third sides meet—is given by the complex ratio -Vud Vub*/Vcd Vcb*, often denoted by the coordinates (rho_bar, eta_bar).
The internal angles of the triangle are labeled alpha, beta, and gamma, and they correspond to CP-violating
Experimentally, the unitarity triangle provides a framework to test the Standard Model: independent measurements of the