Quark- and gluon-jet emission from primordial black holes. II. The emission over the black-hole lifetime

The emission produced over the lifetime of black holes with masses less than M_*≃4-6×10¹⁴ g is investigated by convolving the Hawking emission formulas with a Monte Carlo QCD jet code. Such emission may be astrophysically important if, for example, holes form from initial density perturbations in the early Universe. The quark and gluon decay products contribute significantly to the M_* emission and dominate the lifetime emission from holes with initial masses less than about 10¹⁴ g. The M_* emission shows little sensitivity to the uncertainties in particle-physics models around 100-300 MeV and above 100 GeV. A more precise determination of the mass of a primordial black hole which just expires today is also given as a function of the cosmological matter density and Hubble constant.