Relativistic dipole moment

Transformation of the relativistic electromagnetic dipole moment is discussed. This quantity is set by an antisymmetric 4-tensor of rank 2, the time components of which define magnetic moment and the spatial ones - relativistic electric dipole moment. It is emphasized that experimental fact of absence of own electric dipole moment of elementary particle (when the magnetic moment is present) leads to definite condition for time coordinates of particle constituents - quarks. 7 refs