CKM is an abbreviation that stands for the Cabibbo-Kobayashi-Maskawa matrix. The Cabibbo-Kobayashi-Maskawa matrix is a complex 3x3 unitary matrix used in the field of particle physics to describe how quarks, which are elementary subatomic particles, transform under weak interactions. It is named after theorists Nicola Cabibbo, Makoto Kobayashi, and Toshihide Maskawa, who independently proposed the matrix in the 1960s.
The CKM matrix contains nine elements, which are denoted by V_ij, where i and j refer to the generations of quarks (up, down, charm, strange, top, bottom). Each element represents the probability amplitude for a quark of one flavor to transition into another flavor by the emission or absorption of a weak interaction boson.
By using the CKM matrix, scientists can understand and predict the behavior of quarks in various weak interaction processes, such as the decay of certain particles or the mixing of quark flavors. The matrix plays a crucial role in explaining the phenomenon of CP violation (violation of the combined symmetries of charge and parity) in the Standard Model of particle physics.
The determination of the values of CKM matrix elements is a significant research area, and precise measurements are carried out in high-energy physics experiments, such as those carried out at the Large Hadron Collider (LHC). These measurements help to constrain the parameters of the matrix and test the theory's consistency with observed experimental data.
