Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The singlet scalar as FIMP dark matter   The singlet scalar model is a minimal extension of the Standard Model that
can explain the dark matter. We point out that in this model the dark matter
constraint can be satisfied not only in the already considered WIMP regime but
also, for much smaller couplings, in the Feebly Interacting Massive Particle
(FIMP) regime. In it, dark matter particles are slowly produced in the early
Universe but are never abundant enough to reach thermal equilibrium or
annihilate among themselves. This alternative framework is as simple and
predictive as the WIMP scenario but it gives rise to a completely different
dark matter phenomenology. After reviewing the calculation of the dark matter
relic density in the FIMP regime, we study in detail the evolution of the dark
matter abundance in the early Universe and the predicted relic density as a
function of the parameters of the model. A new dark matter compatible region of
the singlet model is identified, featuring couplings of order 10^-11 to 10^-12
for singlet masses in the GeV to TeV range. As a consequence, no signals at
direct or indirect detection experiments are expected. The relevance of this
new viable region for the correct interpretation of recent experimental bounds
is emphasized.

20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph