Concentrated dark matter: Enhanced small-scale structure from codecaying dark matter

Dror, Jeff A.; Kuflik, Eric; Melcher, Brandon; Watson, Scott

doi:10.1103/physrevd.97.063524

Cited by 63 publications

(65 citation statements)

References 33 publications

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“…To obtain the eros- limits, we used Eq. (8) and set N events = 3.9, corresponding to the number of events expected at the 90% c.l. for the one event observed, assuming Poisson statistics.…”

Section: Iii1 Limits On Point-like Lensesmentioning

confidence: 99%

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Gravitational microlensing by dark matter in extended structures

2020

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Dark matter may be in the form of non-baryonic structures such as compact subhalos and boson stars. Structures weighing between asteroid and solar masses may be discovered via gravitational microlensing, an astronomical probe that has in the past helped constrain the population of primordial black holes and baryonic machos. We investigate the non-trivial effect of the size of and density distribution within these structures on the microlensing signal, and constrain their populations using the eros- and ogle-iv surveys. Structures larger than a solar radius are generally constrained more weakly than point-like lenses, but stronger constraints may be obtained for structures with mass distributions that give rise to caustic crossings or produce larger magnifications.

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Section: Iii1 Limits On Point-like Lensesmentioning

confidence: 99%

“…Using this, we can evaluate the integral over x in Eq. (8) for narrow bins of t E , taking the efficiency ε(t E ) constant in each bin. Summing over the bins gives N events .…”

Section: Nfw Subhalosmentioning

confidence: 99%

Gravitational microlensing by dark matter in extended structures

2020

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“…Since the energy density of relativistic particles decreases more rapidly than that of nonrelativistic particles, any heavy field left over from the inflationary epoch would naturally come to dominate the energy density of the Universe, leading to an early matter-dominated era (EMDE); such a field is only required to decay into radiation before the onset of BBN. Well motivated examples of such heavy fields include hidden-sector particles [13][14][15][16][17][18][19][20][21][22][23][24][25], moduli fields in string theory [26][27][28][29][30][31][32][33], and certain spectator fields invoked to generate primordial curvature variations during inflation [34][35][36][37]. After inflation ends, the inflaton itself can * delos@unc.edu † linden.70@osu.edu ‡ erickcek@physics.unc.edu also behave as a pressureless fluid before its decay [38][39][40][41][42][43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

Breaking a dark degeneracy: The gamma-ray signature of early matter domination

2019

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The Universe's early thermal history is poorly constrained, and it is possible that it underwent a period of early matter domination driven by a heavy particle or an oscillating scalar field that decayed into radiation before the onset of Big Bang nucleosynthesis. The entropy sourced by this particle's decay reduces the cross section required for thermal-relic dark matter to achieve the observed abundance. This degeneracy between dark matter properties and the thermal history vastly widens the field of viable dark matter candidates, undermining efforts to constrain dark matter's identity. Fortunately, an early matter-dominated era also amplifies density fluctuations at small scales and leads to early microhalo formation, boosting the dark matter annihilation rate and bringing smaller cross sections into the view of existing indirect-detection probes. Employing several recently developed models of microhalo formation and evolution, we develop a procedure to derive indirectdetection constraints on dark matter annihilation in cosmologies with early matter domination. This procedure properly accounts for the unique morphology of microhalo-dominated signals. While constraints depend on dark matter's free-streaming scale, the microhalos make it possible to obtain upper bounds as small as σv < ∼ 10 −32 cm 3 s −1 using Fermi-LAT observations of the isotropic gamma-ray background and the Draco dwarf galaxy.

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“…As such, both theoretical and experimental programs have moved beyond the WIMP paradigm. On the theoretical side, explorations of alternative dark matter candidates and production mechanisms have motivated dark matter masses below a GeV [4][5][6][7][8][9][10][11][12][13][14][15][16]. On the experimental side, progress has been made on the size frontier -where ton-scale experiments are needed to search for signals with rates consistent with current bounds.…”

Section: Introductionmentioning

confidence: 99%

Absorption of fermionic dark matter by nuclear targets

Dror

Elor

McGehee

2020

J. High Energ. Phys.

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Absorption of fermionic dark matter leads to a range of distinct and novel signatures at dark matter direct detection and neutrino experiments. We study the possible signals from fermionic absorption by nuclear targets, which we divide into two classes of four Fermi operators: neutral and charged current. In the neutral current signal, dark matter is absorbed by a target nucleus and a neutrino is emitted. This results in a characteristically different nuclear recoil energy spectrum from that of elastic scattering. The charged current channel leads to induced β decays in isotopes which are stable in vacuum as well as shifts of the kinematic endpoint of β spectra in unstable isotopes. To confirm the possibility of observing these signals in light of other constraints, we introduce UV completions of example higher dimensional operators that lead to fermionic absorption signals and study their phenomenology. Most prominently, dark matter which exhibits fermionic absorption signals is necessarily unstable leading to stringent bounds from indirect detection searches. Nevertheless, we find a large viable parameter space in which dark matter is sufficiently long lived and detectable in current and future experiments.

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Concentrated dark matter: Enhanced small-scale structure from codecaying dark matter

Cited by 63 publications

References 33 publications

Gravitational microlensing by dark matter in extended structures

Gravitational microlensing by dark matter in extended structures

Breaking a dark degeneracy: The gamma-ray signature of early matter domination

Absorption of fermionic dark matter by nuclear targets

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