Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Breaking Be: a sterile neutrino solution to the cosmological lithium
  problem   The possibility that the so-called "lithium problem", i.e. the disagreement
between the theoretical abundance predicted for primordial $^7$Li assuming
standard nucleosynthesis and the value inferred from astrophysical
measurements, can be solved through a non-thermal BBN mechanism has been
investigated by several authors. In particular, it has been shown that the
decay of a MeV-mass particle, like, e.g., a sterile neutrino, decaying after
BBN not only solves the lithium problem, but also satisfies cosmological and
laboratory bounds, making such a scenario worth to be investigated in further
detail. In this paper, we constrain the parameters of the model with the
combination of current data, including Planck 2015 measurements of temperature
and polarization anisotropies of the CMB, FIRAS limits on spectral distortions,
astrophysical measurements of primordial abundances and laboratory constraints.
We find that a sterile neutrino with mass $M_S=4.35_{-0.17}^{+0.13}\,MeV$ (at
$95\%$ c.l.), a decay time $\tau_S=1.8_{-1.3}^{+2.5}\cdot 10^5\,s$ (at $95\%$
c.l.) and an initial density $\bar{n}_S/\bar{n}_{cmb}=1.7_{-0.6}^{+3.5}\cdot
10^{-4}$ (at $95\%$ c.l.) in units of the number density of CMB photons,
perfectly accounts for the difference between predicted and observed $^7$Li
primordial abundance. This model also predicts an increase of the effective
number of relativistic degrees of freedom at the time of CMB decoupling $\Delta
N_{eff}^{cmb}\equiv N_{eff}^{cmb}-3.046=0.34_{-0.14}^{+0.16}$ at $95\%$ c.l..
The required abundance of sterile neutrinos is incompatible with the standard
thermal history of the Universe, but could be realized in a low reheating
temperature scenario. We provide forecasts for future experiments finding that
the combination of measurements from the COrE+ and PIXIE missions will allow to
significantly reduce the permitted region for the sterile lifetime and density.

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The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: chem-ph