Sensitivity projections for dark matter searches with the Fermi large area telescope

Charles, E.; Sánchez‐Conde, Miguel A.; Anderson, B.; Caputo, R.; Cuoco, A.; Mauro, Mattia Di; Drlica-Wagner, A.; Gomez-Vargas, G. A.; Meyer, M.; Tibaldo, L.; Wood, M.; Zaharijaš, Gabrijela; Zimmer, S.; Ajello, M.; Albert, A.; Baldini, Luca; Bechtol, K.; Bloom, E. D.; Ceraudo, Francesco; Cohen-Tanugi, J.; Digel, S. W.; Gaskins, Jennifer; Gustafsson, M.; Mirabal, N.; Razzano, M.

doi:10.1016/j.physrep.2016.05.001

Cited by 166 publications

(181 citation statements)

References 347 publications

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“…Projection studies include: CTA 5h [11] for photon-lines from GC (see refs. [41,42] for similar results), CTA 500h [43,44] for photon-continuum from GC, and Fermi-LAT 15 years for photon-continuum from 16 DG [45] (see ref. [46] for CTA projections).…”

Section: Annihilations At Gc and Dgmentioning

confidence: 60%

Very Degenerate Higgsino Dark Matter

Chun¹,

Jung²,

Park³

2017

J. High Energ. Phys.

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We present a study of the Very Degenerate Higgsino Dark Matter (DM), whose mass splitting between the lightest neutral and charged components is O(1) MeV, much smaller than radiative splitting of 355 MeV. The scenario is realized in the minimal supersymmetric standard model by small gaugino mixings. In contrast to the pure Higgsino DM with the radiative splitting only, various observable signatures with distinct features are induced. First of all, the very small mass splitting makes (a) sizable Sommerfeld enhancement and Ramsauer-Townsend (RT) suppression relevant to ∼1 TeV Higgsino DM, and (b) Sommerfeld-Ramsauer-Townsend effect saturate at lower velocities v/c 10 −3 . As a result, annihilation signals can be large enough to be observed from the galactic center and/or dwarf galaxies, while the relative signal sizes can vary depending on the locations of Sommerfeld peaks and RT dips. In addition, at collider experiments, stable chargino signatures can be searched for to probe the model in the future. DM direct detection signals, however, depend on the Wino mass; even no detectable signals can be induced if the Wino is heavier than about 10 TeV.

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Section: Annihilations At Gc and Dgmentioning

confidence: 60%

Very Degenerate Higgsino Dark Matter

Chun¹,

Jung²,

Park³

2017

J. High Energ. Phys.

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“…However, using the parameters in the allowed regions shown in Sec. 5, we have found that the pair annihilation cross section is much smaller than the current upper bounds obtained from, for example, the Fermi-LAT experiments [111]. 8 There is another process for the RHN DM to scatter off with nuclei via Z ′ -boson exchange.…”

Section: Direct Detection Of Rhn Dmmentioning

confidence: 75%

Right-handed neutrino dark matter in the classically conformal U(1)′ extended standard model

2017

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We consider the dark matter (DM) scenario in the context of the classically conformal U(1) ′ extended standard model (SM), with three right-handed neutrinos (RHNs) and the U(1) ′ Higgs field. The model is free from all the U(1) ′ gauge and gravitational anomalies in the presence of the three RHNs. We introduce a Z 2 -parity in the model, under which an odd-parity is assigned to one RHN, while all the other particles is assigned to be Z 2 -even, and hence the Z 2 -odd RHN serves as a DM candidate. In this model, the U(1) ′ gauge symmetry is radiatively broken through the Coleman-Weinberg mechanism, by which the electroweak symmetry breaking is triggered. There are three free parameters in our model, the U(1) ′ charge of the SM Higgs doublet (x H ), the new U(1) ′ gauge coupling (g X ), and the U(1) ′ gauge boson (Z ′ ) mass (m Z ′ ), which are severely constrained in order to solve the electroweak vacuum instability problem, and satisfy the LHC Run-2 bounds from the search for Z ′ boson resonance. In addition to these constraints, we investigate the RHN DM physics. Because of the nature of classical conformality, we find that a RHN DM pair mainly annihilates into the SM particles through the Z ′ boson exchange. This is the socalled Z ′ -portal DM scenario. Combining the electroweak vacuum stability condition, the LHC Run-2 bounds, and the cosmological constraint from the observed DM relic density, we find that all constrains complementarily work to narrow down the allowed parameter regions, and, especially, exclude m Z ′ 3.5 TeV. For the obtained allowed regions, we calculate the spin-independent cross section of the RHN DM with nucleons. We find that the resultant cross section well below the current experimental upper bounds.

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“…[38,39,41,[53][54][55] for the 95% (lighter) and 68% (darker) containment limits of the expected exclusion bound. As we can see, for their improved energy resolution, these experiments can probe a vast majority of the considered parameter space, covering in particular almost the totality of the region where the CoyDM model reproduces the GC photon excess.…”

Section: Gc Excessmentioning

confidence: 98%

“…We also consider the impact of the DAMPE [38,39,41], HERD [42] and GAMMA-400 [43] next generation experiments by estimating their reach from refs. [38,39,41,[53][54][55].…”

Section: Gc Excessmentioning

confidence: 99%

Gamma-ray line constraints on coy dark matter

2017

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Coy dark matter is an effective scheme in which a fermionic dark matter candidate interacts with the Standard Model fermions via a pseudoscalar mediator. This simple setup avoids the strong constraints posed by direct detection experiments in a natural way and explains, on top of the observed dark matter relic abundance, the spatially extended γ-ray excess recently detected at the Galactic Center. In this Letter we study the phenomenology of coy dark matter accounting for a novel signature of the model: the diphoton annihilation signal induced by the Standard Model fermions at the loop level. By challenging the model with the observations of spheroidal dwarf satellite galaxies and the results of γ-ray line searches obtained by the Fermi LAT experiment, we assess its compatibility with the measured dark matter relic abundance and the Galactic Center excesses. We show that despite the γ-ray line constraint rules out a significant fraction of the considered parameter space, the region connected to the observed Galactic Center excess remains currently viable. Nevertheless, we find that nextgeneration experiments such as DAMPE, HERD and GAMMA-400 have the potential to probe exhaustively this elusive scenario. [I] IntroductionThe matter content of our Universe is dominated by a component which, differently from ordinary matter, interacts at most very weakly with the photons of the Standard Model (SM) -the dark matter (DM). It is usually assumed that DM consists of stable and weaklyinteracting massive particles (WIMPs), which are thermal relics of dynamics once active in the hot early Universe. The reason behind the success of this picture is that particles with masses and annihilation cross sections set by the electroweak scale yield, in a natural way, DM relic densities of the order of the observed one. The basis of this remarkable coincidence lies in the freeze-out mechanism (for a review: [1, 2]), a natural consequence of the interplay between particle physics and an expanding Universe. For its simplicity and the appealing connection to frameworks like supersymmetry, the WIMP model became the paradigm of DM and shaped the dedicated long term experimental program. Direct detection experiments as XENON100 [3], PANDA [4] and LUX [5] investigate the possible elastic scattering of DM on SM particles mediated by the postulated weak-scale interactions. Similarly, indirect detection investigations scrutinise potential traces of DM annihilations proceeding in the Galaxy or on cosmological scales via the same interactions. Finally, the direct production of DM particles in weak-scale phenomena is studied at collider experiments such as the LHC at CERN [6,7].To date, in spite of the intense experimental effort, the nature and the properties of DM remain still a puzzle. Furthermore, the negative results of dedicated experiments accumulated so far have started to shake the belief of the community in the WIMP paradigm. In fact, the non-detection of supersymmetric partners of SM particles at collider experiments has impair...

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Sensitivity projections for dark matter searches with the Fermi large area telescope

Cited by 166 publications

References 347 publications

Very Degenerate Higgsino Dark Matter

Very Degenerate Higgsino Dark Matter

Right-handed neutrino dark matter in the classically conformal U(1)′ extended standard model

Gamma-ray line constraints on coy dark matter

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