Colder freeze-in axinos decaying into photons

We present a thorough discussion of light dark matter produced via freeze-in in two-body decays A → B DM. If A and B are quasi-degenerate, the dark matter particle has a cold spectrum even for keV masses. We show this explicitly by calculating the transfer function that encodes the impact on structure formation. As examples for this setup we study extended seesaw mechanisms with a spontaneously broken global U (1) symmetry, such as the inverse seesaw. The keV-scale pseudo-Goldstone dark matter particle is then naturally produced cold by the decays of the quasi-degenerate right-handed neutrinos.

Section: Extended Inverse Seesawmentioning

confidence: 99%

Cold light dark matter in extended seesaw models

Boulebnane

Heeck

Nguyen

et al. 2018

“…♦11 This simplified model virtually corresponds to a light axino FIMP model considered in Refs. [99,189]. The axino FIMP model is based on a supersymmetric version of Dine-Fischler-Srednicki-Zhitnitsky axion model [190,191].…”

Section: Simplified Fimp Modelmentioning

confidence: 99%

“…with the Yukawa coupling y f . One can identify f as top quark (again φ as Higgs) in the axino FIMP model [99,189]. We assume the mass hierarchy of m Ψ > m φ m f .…”

Section: Case B: Decay With Scatteringmentioning

confidence: 99%

Fingerprint matching of beyond-WIMP dark matter: neural network approach

Bae

Jinno

Kamada

et al. 2020

Self Cite

Galactic-scale structure is of particular interest since it provides important clues to dark matter properties and its observation is improving. Weakly interacting massive particles (WIMPs) behave as cold dark matter on galactic scales, while beyond-WIMP candidates suppress galactic-scale structure formation. Suppression in the linear matter power spectrum has been conventionally characterized by a single parameter, the thermal warm dark matter mass. On the other hand, the shape of suppression depends on the underlying mechanism. It is necessary to introduce multiple parameters to cover a wide range of beyond-WIMP models. Once multiple parameters are introduced, it becomes harder to share results from one side to the other. In this work, we propose adopting neural network technique to facilitate the communication between the two sides. To demonstrate how to work out in a concrete manner, we consider a simplified model of light feebly interacting massive particles. ♦1 We refer readers to Ref. [10] for a recent review of gravitational probes of DM properties. ♦2 Prominent examples are the missing satellite problem [13][14][15][16][17], core-cusp problem [18][19][20][21], and toobig-to-fail problem [22][23][24][25][26][27]. We refer readers to Ref.[28] for a recent review and further details. Stateof-the-art hydrodynamical simulations have been demonstrating that astrophysical processes also play an important role [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. There have also been reports that small-scale issues persist even in state-of-the-art hydrodynamical simulations [47][48][49][50][51][52][53][54][55]. To our best knowledge, it is still controversial if astrophysical processes fully resolve the small-scale issues.One can work out each step independently by parametrizing the linear matter power spectrum. See the red flow in Fig. 1. A single parameter has been adopted conventionally: the thermal WDM mass m WDM . ♦3 On the other hand, a single parameter is not enough to cover a wide range of beyond-WIMP scenarios. For this purpose, Ref.[88] introduces the 3parameter ({α, β, γ}) characterization of the linear matter power spectrum. On one side, one (likely particle physicist) can construct a map of model parameters onto {α, β, γ}. On the other side, one (likely astrophysicist) can provide observational constraints on {α, β, γ}, as indeed done for the Lyman-α forest data in Ref. [89]. By combining results from the two sides, one can obtain observational constraints on a given beyond-WIMP scenario. Nevertheless, once multiple parameters are introduced, it becomes hard to share results from one side to the other.In this respect, we propose building ready-to-use networks: one maps model parameters onto {α, β, γ}; and another maps {α, β, γ} onto observables. One can use these networks to examine models without repeating the aforementioned time-consuming procedure. Ideally, it would be the most efficient if one obtained analytic maps, but in reality, it is hard to establish such analytic maps....

“…Similar analyses for axino LSP in bilinear/trilinear RPV models were carried out in Refs. [18][19][20][21][22][23][24][25][26][27].In a recent work [28], we analyzed a multicomponent DM scenario with axino LSP and gravitino NLSP. This is a decaying dark matter (DDM) scenario, where the gravitino in addition to the RPV decay channel into photon-neutrino, also undergoes an R-parity conserving (RPC) decay into axion-axino.…”

mentioning

confidence: 99%

MeV-GeV γ-ray telescopes probing axino LSP/gravitino NLSP as dark matter in the μνSSM

Gomez-Vargas

López-Fogliani

Muñoz

et al. 2020

In R-parity violating supersymmetry, the gravitino as the lightest supersymmetric particle (LSP) is a good candidate for dark matter, with the interesting characteristic to be detectable through γ-ray telescopes. We extend this analysis considering an axino next-to-LSP (NLSP) as a coexisting dark matter particle contributing with a detectable signal in the γ-ray spectrum. The analysis is carried out in the framework of the µνSSM, which solves the µ problem reproducing simultaneously neutrino data only with the addition of right-handed neutrinos. We find that important regions of the parameter space can be tested by future MeV-GeV γ-ray telescopes through the line signal coming from the decay of the axino NLSP into photon-neutrino. In a special region, a double-line signal from axino NLSP and gravitino LSP is possible with both contributions detectable. IntroductionGravitino (ψ 3/2 ) LSP or axino (ã) LSP are interesting candidates for dark matter (DM) in the framework of supersymmetry (SUSY). In addition, in SUSY models where there is Rparity violation (RPV) these particles decay with a lifetime longer than the age of the Universe, producing a line signal potentially detectable in γ-ray telescopes. This was analyzed for the gravitino LSP in Refs. [1][2][3][4][5][6][7][8][9][10][11] in the context of bilinear/trilinear RPV models [12], and in Refs. [13][14][15][16] in the 'µ from ν' supersymmetric standard model (µνSSM) [17]. Similar analyses for axino LSP in bilinear/trilinear RPV models were carried out in Refs. [18][19][20][21][22][23][24][25][26][27].In a recent work [28], we analyzed a multicomponent DM scenario with axino LSP and gravitino NLSP. This is a decaying dark matter (DDM) scenario, where the gravitino in addition to the RPV decay channel into photon-neutrino, also undergoes an R-parity conserving (RPC) decay into axion-axino. The analysis was carried out in the framework of the µνSSM, where couplings involving right-handed neutrinos are introduced solving the µ-problem and reproducing simultaneously the neutrino data [17,[29][30][31][32]. A brief discussion and bibliography about the interesting phenomenology associated to the µνSSM, can be found in Ref. [28], where it was shown that significant regions of the parameter space of the model can be probed through a line signal coming from the axino decay. A doubleline signal as smoking gun through the further contribution of the gravitino decay is also possible in a subset of those regions.Here we want to extend our previous work, analyzing the opposite DDM scenario where the gravitino is the LSP and the axino the NLSP. Their masses, although model dependent can be of the same order in several realistic scenarios [33][34][35][36][37] such as in supergravity, and therefore if the axino (gravitino) is the LSP the gravitino (axino) becomes naturally the NLSP. As a consequence, the NLSP decays into the LSP plus an axion. In this not yet explored RPV scenario with gravitino LSP and axino NLSP, we will study its cosmological properties as well as the associa...