{
  "id": "1512.09117",
  "version": "v1",
  "published": "2015-12-30T20:49:09.000Z",
  "updated": "2015-12-30T20:49:09.000Z",
  "title": "Thermal relics as hot, warm and cold dark matter in power-law $f(R)$ gravity",
  "authors": [
    "David Wenjie Tian"
  ],
  "categories": [
    "astro-ph.CO",
    "gr-qc",
    "hep-ph"
  ],
  "abstract": "We investigate the thermal relics as hot, warm and cold dark matter in $\\mathscr{L}=\\varepsilon^{2-2\\beta}R^\\beta+{16\\pi}m_{\\text{Pl}}^{-2}\\mathscr{L}_m$ gravity, where $\\varepsilon$ is a constant balancing the dimension of the field equation, and $1<\\beta<(4+\\sqrt{6})/5$ for the positivity of energy density and temperature. If light neutrinos serve as hot/warm relics, the entropic number of statistical degrees of freedom $g_{*s}$ at freeze-out and thus the predicted fractional energy density $\\Omega_\\psi h^2$ are $\\beta-$dependent, which relaxes the standard mass bound $\\Sigma m_\\nu$. For cold relics, by exactly solve the simplified Boltzmann equation in both relativistic and nonrelativistic regimes, we show that the Lee-Weinberg bound for the mass of heavy neutrinos can be considerably relaxed, and the 'WIMP miracle\" for weakly interacting massive particles (WIMPs) gradually invalidates as $\\beta$ deviates from $\\beta=1^+$. The whole framework reduces to become that of GR in the limit $\\beta\\to 1^+$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-12-30T20:49:09.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cold dark matter",
      "thermal relics",
      "predicted fractional energy density",
      "light neutrinos serve",
      "standard mass bound"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015arXiv151209117W",
      "inspire": 1411607
    }
  }
}