Introductory Remark

Merle, Jean-Christophe

doi:10.1007/978-94-007-5998-5_56

Cited by 5 publications

(7 citation statements)

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“…15 The suppression of structure at small scales can also arise due to free-streaming of the DM particles if DM is warm [233][234][235], e.g. in the form of sterile neutrinos [12][13][14][15][16][17][18][19][20][21][22][23][24]. 16 For bounds on the protohalo minimum mass for the cases that the kinetic decoupling of DM is determined by its interactions with SM particles via effective operators, see Ref.…”

Section: Structure Formation and Galactic Dynamicsmentioning

confidence: 99%

“…Asymmetric DM is one of a number of well-motivated alternatives to the WIMP solution -other examples are keV-scale sterile neutrinos [12][13][14][15][16][17][18][19][20][21][22][23][24], axions [25][26][27][28][29][30][31][32][33], and Qballs 3 [34][35][36][37][38][39] -which all deserve serious attention. It does not have the (interesting) WIMP feature of a tight connection between the thermal freeze-out process, indirect detection, direct detection and collider production.…”

Section: Introductionmentioning

confidence: 99%

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Review of Asymmetric Dark Matter

Petraki

Volkas

2013

Int. J. Mod. Phys. A

525

523

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Asymmetric dark matter models are based on the hypothesis that the present-day abundance of dark matter has the same origin as the abundance of ordinary or "visible" matter: an asymmetry in the number densities of particles and antiparticles. They are largely motivated by the observed similarity in the mass densities of dark and visible matter, with the former observed to be about five times the latter. This review discusses the construction of asymmetric dark matter models, summarizes cosmological and astrophysical implications and bounds, and touches on direct detection prospects and collider signatures.

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Section: Structure Formation and Galactic Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Review of Asymmetric Dark Matter

Petraki

Volkas

2013

Int. J. Mod. Phys. A

525

523

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“…If the lightest sterile neutrino has a keV mass scale, it is a warm darkmatter candidate [78]. The couplings of sterile neutrinos are usually too small to have been in thermal equilibrium in the early universe.…”

Section: Neutrinosmentioning

confidence: 99%

Indirect and direct search for dark matter

Klasen

Pohl

Sigl

2015

Progress in Particle and Nuclear Physics

167

134

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The majority of the matter in the universe is still unidentified and under investigation by both direct and indirect means. Many experiments searching for the recoil of dark-matter particles off target nuclei in underground laboratories have established increasingly strong constraints on the mass and scattering cross sections of weakly interacting particles, and some have even seen hints at a possible signal. Other experiments search for a possible mixing of photons with light scalar or pseudo-scalar particles that could also constitute dark matter. Furthermore, annihilation or decay of dark matter can contribute to charged cosmic rays, photons at all energies, and neutrinos. Many existing and future ground-based and satellite experiments are sensitive to such signals. Finally, data from the Large Hadron Collider at CERN are scrutinized for missing energy as a signature of new weakly interacting particles that may be related to dark matter. In this review article we summarize the status of the field with an emphasis on the complementarity between direct detection in dedicated laboratory experiments, indirect detection in the cosmic radiation, and searches at particle accelerators.Comment: 74 pages, 27 figures, to be published in "Progress in Particle and Nuclear Physics" 201

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“…The ideas used to obtain light sterile neutrinos thereby range from the application of the Froggatt-Nielsen mechanism [19,20,21], over flavour symmetries [22,23,24], extra dimensions [25,26,27], extensions of the seesaw mechanism [21,28,29,30,31,32,33,34], composite neutrinos [35,36], global symmetries [37,38], loop suppressions [39], to gravitational effects [40] -see Ref. [41] for a recent review. Even lighter sterile neutrinos have also attracted considerable interest (see, e.g., Refs.…”

Section: Introductionmentioning

confidence: 99%

New production mechanism for keV sterile neutrino Dark Matter by decays of frozen-in scalars

Merle

Niro

Schmidt

2014

J. Cosmol. Astropart. Phys.

148

195

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We propose a new production mechanism for keV sterile neutrino Dark Matter. In our setting, we assume the existence of a scalar singlet particle which never entered thermal equilibrium in the early Universe, since it only couples to the Standard Model fields by a really small Higgs portal interaction. For suitable values of this coupling, the scalar can undergo the so-called freeze-in process, and in this way be efficiently produced in the early Universe. These scalars can then decay into keV sterile neutrinos and produce the correct Dark Matter abundance. While similar settings in which the scalar does enter thermal equilibrium and then freezes out have been studied previously, the mechanism proposed here is new and represents a versatile extension of the known case. We perform a detailed numerical calculation of the DM production using a set of coupled Boltzmann equations, and we illustrate the successful regions in the parameter space. Our production mechanism notably can even work in models where active-sterile mixing is completely absent. * no primordial lepton asymmetry is present in the early Universe [17,18]. Indeed, a large enough primordial lepton asymmetry could lead to a resonant transition -the so-called Shi-Fuller mechanism [46]-producing a considerable amount of sterile neutrinos with a cooler non-thermal spectrum, in addition to the ones produced by the DW mechanism. In this way, some bounds could be evaded. On the other hand, in frameworks where the SM gauge group is extended, the sterile neutrinos could be charged non-trivially under the full gauge group and be sterile only with respect to SM interactions. In this case, although this is not compulsory [47], thermal production of keV neutrinos could be revived [48,49]. However, this mechanism would generically produce too much DM and by this overclose the Universe, thus requiring some dilution by the production of additional entropy [50]. Moreover, it could get into trouble with bounds from Big Bang nucleosynthesis [51].Probably the most versatile production mechanism from a particle physics point of view is the non-thermal production of keV sterile neutrinos by the decays of particles [52,53,54,55,56], in particular of singlet scalars. Examples of this production mechanism exists for the scalar being an inflaton [57,58] or a more general equilibrated scalar singlet particle [59,60]. This case is particularly interesting because it tends to lead to smaller bounds on the mass of the keV neutrino, a desirable feature, since keV-neutrinos with too large masses could be in danger with X-ray bound. For a recent collections of observational bounds from the non-observation of the decay into a light neutrino and a photon, N 1 → νγ, see Refs. [17,18,61] and references therein. 1 The aim of this paper is to study a variant of the scalar decay production mechanism discussed in Refs. [59,60]. The decisive point is that the scalar σ, which decays into the keV neutrinos, σ → N 1 N 1 , has to be efficiently produced in the early Universe, as otherwise it would ...

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Introductory Remark

Cited by 5 publications

References 0 publications

Review of Asymmetric Dark Matter

Review of Asymmetric Dark Matter

Indirect and direct search for dark matter

New production mechanism for keV sterile neutrino Dark Matter by decays of frozen-in scalars

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