Thermal relics as hot, warm and cold dark matter in power-law f(R)\n gravity

2015/12/30 by David Wenjie Tian, Tian, David Wenjie
Physics and Astronomy · Computer Science · #Cosmology and Gravitation Theories #Black Holes and Theoretical Physics #Computational Physics and Python Applications

paper · pdf · doi:10.48550/arxiv.1512.09117

Abstract

We investigate the thermal relics as hot, warm and cold dark matter in\n mathscrL=\ε^2-2\βR^\β+16\πm_\Pl^-2 mathscrL_m\ngravity, where \ε is a constant balancing the dimension of the field\nequation, and 1<\β<(4+\√(6))/5 for the positivity of energy density and\ntemperature. If light neutrinos serve as hot/warm relics, the entropic number\nof statistical degrees of freedom g_*s at freeze-out and thus the predicted\nfractional energy density \Ω_\ψ h² are \β-dependent, which\nrelaxes the standard mass bound \Σ m_\ν. For cold relics, by exactly\nsolve the simplified Boltzmann equation in both relativistic and\nnonrelativistic regimes, we show that the Lee-Weinberg bound for the mass of\nheavy neutrinos can be considerably relaxed, and the 'WIMP miracle" for weakly\ninteracting massive particles (WIMPs) gradually invalidates as \β deviates\nfrom \β=1⁺. The whole framework reduces to become that of GR in the limit\n\β\→ 1⁺.\n

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