The Photino Induced Distortion of the CMBR Blackbody Spectrum

Abstract

It is shown that photon--photino inter-conversions (if exist) may result in a detectable CMBR spectrum distortion which amplitude depends on photino properties, such as its mass. An upper bound on the distortion parameter determined from the recent COBE-FIRAS data, hence, sets a lower bound on the photino mass, $m_{\tildeγ} \gtrsim 300 eV$.