Scalar singlet dark matter in non-standard cosmologies

Bernal, Nicolás; Cosme, Catarina; Tenkanen, Tommi; Vaskonen, Ville

doi:10.1140/epjc/s10052-019-6550-9

Cited by 64 publications

(49 citation statements)

References 139 publications

(171 reference statements)

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“…Thus different cosmological assumptions can potentially lead to significant enhancements of the DM relic density due to UV freeze-in. Additionally, it was recently highlighted that the initial value of ω impacts the DM relic density if it is established due to freeze-out or renormalisable (IR) freeze-in during the era of particle decays leading to the transition to radiation domination [19,23]. This paper is structured as follows: In Section 2 we outline the general framework in a model independent approach, in particular we derive the dependence of the critical dimension n c and the boost factor B on the equation of state prior to reheating ω for general operator dimension parameterised by n. We subsequently explore how the DM abundance varies for different choices of ω and n. In Section 3 we highlight four specific examples in which the DM abundance receives a significant enhancement, specifically we examine gravitino DM in High Scale Supersymmetry [4,39], the moduli portal [7], the vector Higgs portal, and the massive spin-2 portal [6].…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet freeze-in and non-standard cosmologies

Bernal

Elahi

Maldonado

et al. 2019

J. Cosmol. Astropart. Phys.

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105

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A notable feature of UV freeze-in is that the relic density is strongly dependent on the highest temperatures of the thermal bath, and a common assumption is that the relevant "highest temperature" should be the reheating temperature after inflation T RH . However, the temperature of the thermal bath can be significantly higher in certain scenarios, reaching a value denoted T max , a fact which is only apparent away from the instantaneous decay approximation. Interestingly, it has been shown that if the operators are of sufficiently high mass dimension then the dark matter abundance can be enhanced by a "boost factor" depending on (T max /T RH ) relative to naive estimates assuming instantaneous reheating. We highlight here that in non-standard cosmological histories the critical mass dimension of the operator above at which the instantaneous decay approximation breaks down, and the exponent of the boost factor, depend on the equation of state ω prior to reheating. We highlight four examples in which the dark matter abundance receives a significant enhancement in the context of gravitino dark matter, the moduli portal, the Higgs portal, and the spin-2 portal (as might arise in bimetric gravity models). We comment on the transition from kination domination to radiation domination as a motivated example of non-standard cosmologies. arXiv:1909.07992v1 [hep-ph]

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Section: Introductionmentioning

confidence: 99%

Ultraviolet freeze-in and non-standard cosmologies

Bernal

Elahi

Maldonado

et al. 2019

J. Cosmol. Astropart. Phys.

Self Cite

105

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“…Instead of performing an intensive full-parameter scan, in this paper we will perform an analytical study of the different representative cases previously mentioned, which allows us to capture the essence of each scenario. Results of an exhaustive scan over the full parameter space in the usual freeze-out and freezein cases are presented in a companion paper [39], where we also discuss the effect of other non-standard cosmological histories. However, as we will show, already with the best-motivated non-standard case, an early phase of matter-domination, the DM phenomenology is very rich when the effect of DM self-interactions is taken into account, which is one of the reasons why we devote a separate paper for the analysis of this scenario only.…”

Section: Introductionmentioning

confidence: 99%

Phenomenology of self-interacting dark matter in a matter-dominated universe

2019

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We study production of self-interacting dark matter (DM) during an early matter-dominated phase. As a benchmark scenario, we consider a model where the DM consists of singlet scalar particles coupled to the visible Standard Model (SM) sector via the Higgs portal. We consider scenarios where the initial DM abundance is set by either the usual thermal freeze-out or an alternative freeze-in mechanism, where DM was never in thermal equilibrium with the SM sector. For the first time, we take the effect of self-interactions within the hidden sector into account in determining the DM abundance, reminiscent to the Strongly Interacting Massive Particle (SIMP) scenario. In all cases, the number density of DM may change considerably compared to the standard radiation-dominated case, having important observational and experimental ramifications.

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“…We note that several works exist in the literature on supersymmetric U (1) extensions of MSSM and their implications on dark matter and collider searches (see, e.g., [29]). Also, several works on signatures of long-lived particles at colliders with freeze-in dark matter have appeared recently [30][31][32][33][34][35] as well as scenarios testing for freeze-in via direct detection [36][37][38][39][40] and indirect detection [41,42]. The analysis of this work is significantly different from these.…”

Section: Introductionmentioning

confidence: 99%

A long-lived stop with freeze-in and freeze-out dark matter in the hidden sector

Aboubrahim

Feng

Nath

2020

J. High Energ. Phys.

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In extended supersymmetric models with a hidden sector the lightest R-parity odd particle can reside in the hidden sector and act as dark matter. We consider the case when the hidden sector has ultraweak interactions with the visible sector. An interesting phenomenon arises if the LSP of the visible sector is charged in which case it will decay to the hidden sector dark matter. Due to the ultraweak interactions, the LSP of the visible sector will be long-lived decaying outside the detector after leaving a track inside. We investigate this possibility in the framework of a U (1) X -extended MSSM/SUGRA model with a small gauge kinetic mixing and mass mixing between the U (1) X and U (1) Y where U (1) Y is the gauge group of the hypercharge. Specifically we investigate the case when the LSP of MSSM is a stop which decays into the hidden sector dark matter and has a lifetime long enough to traverse the LHC detector without decay. It is shown that such a particle can be detected at the HL-LHC and HE-LHC as an R-hadron which will look like a slow moving muon with a large transverse momentum p T and so can be detected by the track it leaves in the inner tracker and in the muon spectrometer. Further, due to the ultraweak couplings between the hidden sector and the MSSM fields, the dark matter particle has a relic density arising from a combination of the freeze-out and freeze-in mechanisms. It is found that even for the ultraweak or feeble interactions the freeze-out contribution relative to freeze-in contribution to the relic density is substantial to dominant, varying between 30% to 74% for the model points considered. It is subdominant to freeze-in for relatively small stop masses with relatively larger stop annihilation cross-sections and the dominant contribution to the relic density for relatively large stop masses and relatively smaller stop annihilation cross-sections. Our analysis shows that the freeze-out contribution must be included for any realistic analysis even for dark matter particles with ultraweak or feeble interactions with the visible sector. A discovery of a long-lived stop as the lightest particle of the MSSM may point to the nature of dark matter and its production mechanism in the early universe. *

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Scalar singlet dark matter in non-standard cosmologies

Cited by 64 publications

References 139 publications

Ultraviolet freeze-in and non-standard cosmologies

Ultraviolet freeze-in and non-standard cosmologies

Phenomenology of self-interacting dark matter in a matter-dominated universe

A long-lived stop with freeze-in and freeze-out dark matter in the hidden sector

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