Cosmic background radiation spectral distortion and radiative decays of relic neutral particles

The recently observed excess of photons on a short wavelength side of the peak of a cosmic background radiation spectrum can be described by radiative decays of relic neutral particles. The lifetime and mass of a decaying particle must satisfy the following conditions: 2x109 s<τ<3.6x1014 s, 0.4 eV<m<170 eV. The transitional magnetic moment must be of the order of (3x10-9-8x10-8) μb, and the interaction of new particles with the usual matter must be rather strong. The generalization of the standard SU(3)xSU(2)xU(1) model is presented which includes new particles with the desired properties. 18 refs.; 3 figs.; 2 tabs