PRECISION ESTIMATE OF COSMOLOGICAL AND PARTICLE PARAMETERS IN THE DECAYING-DARK-MATTER HYPOTHESIS

I have recently proposed that both H i regions of the Galaxy and Lyman- clouds are mainly ionized by decaying dark matter. Here I point out that to avoid an excessive metagalactic ionizing flux F, the energy E of the decay photons must be severely constrained. It then follows that the mass m1 and lifetime of the decaying particles, the flux F, the density and age tU of the Universe, (=/crit), and the Hubble constant H also have to be severely constrained. The validity of our theory requires that E=14.4 0.5 eV, m1=28.9 1.1 eV, =(2+1)×1023 sec, F=(3.8 2.2)×105 cm-2 sec-1, =(6.140.26×10-30 g cm-3, tU1.2×1010yr, 1, and H=551 km sec-1 Mpc-1. © 1990 The American Physical Society.