Abstract:Models of Dark Matter (DM) can leave unique imprints on the Universe’s small scale structure by boosting density perturbations on small scales. We study the capability of Pulsar Timing Arrays to search for, and constrain, subhalos from such models. The models of DM we consider are ordinary adiabatic perturbations in ΛCDM, QCD axion miniclusters, models with early matter domination, and vector DM produced during inflation. We show that ΛCDM, largely due to tidal stripping effects in the Milky Way, is out of rea… Show more
“…This implies a period of Early Matter Domination, where metric perturbations on small scales can enter the horizon and grow. Scales that were inside the horizon during this period of EMD, can give rise to enhanced matter power spectrum on small scales, corresponding to subhalos of mass 10 −15 −10 −11 M for T RH = 1 GeV and 10 −9 −10 −4 M for T RH = 1 MeV [67].…”
Motivated by the observed ratio of dark matter to baryon mass densities, ρ D /ρ B 5, we propose a theory of dark-color unification. In this theory, the dark to visible baryon masses are fixed by the ratio of dark to visible confinement scales, which are determined to be nearby in mass through the unification of the dark and visible gauge theories at a high scale. Together with a mechanism for darko-baryo-genesis, which arises naturally from the grand unification sector, the mass densities of the two sectors must be nearby, explaining the observed mass density of dark matter. We focus on the simplest possible example of such a theory, where Standard Model color SU(3) C is unified with dark color SU(2) D into SU(5) at an intermediate scale of around 10 8 − 10 9 GeV. The dark baryon consists of two dark quarks in an isotriplet configuration. There are a range of important cosmological, astrophysical and collider signatures to explore, including dark matter self-interactions, early matter domination from the dark hadrons, gravitational wave signatures from the hidden sector phase transition, contributions to flavor observables, as well as Hidden Valley-like signatures at colliders.
“…This implies a period of Early Matter Domination, where metric perturbations on small scales can enter the horizon and grow. Scales that were inside the horizon during this period of EMD, can give rise to enhanced matter power spectrum on small scales, corresponding to subhalos of mass 10 −15 −10 −11 M for T RH = 1 GeV and 10 −9 −10 −4 M for T RH = 1 MeV [67].…”
Motivated by the observed ratio of dark matter to baryon mass densities, ρ D /ρ B 5, we propose a theory of dark-color unification. In this theory, the dark to visible baryon masses are fixed by the ratio of dark to visible confinement scales, which are determined to be nearby in mass through the unification of the dark and visible gauge theories at a high scale. Together with a mechanism for darko-baryo-genesis, which arises naturally from the grand unification sector, the mass densities of the two sectors must be nearby, explaining the observed mass density of dark matter. We focus on the simplest possible example of such a theory, where Standard Model color SU(3) C is unified with dark color SU(2) D into SU(5) at an intermediate scale of around 10 8 − 10 9 GeV. The dark baryon consists of two dark quarks in an isotriplet configuration. There are a range of important cosmological, astrophysical and collider signatures to explore, including dark matter self-interactions, early matter domination from the dark hadrons, gravitational wave signatures from the hidden sector phase transition, contributions to flavor observables, as well as Hidden Valley-like signatures at colliders.
“…As a result, we generally expect a peak in density perturbations between the two scales, leading to a potentially observable enhancement in the local subhalo abundance. The ensuing altered predictions of the ionization history as well as of the halo-mass function in the late Universe can be probed with various strategies [81,[86][87][88][89][90]. In particular, future Pulsar Timing Arrays (PTA) will be able to constrain the abundance of local subhalos down to a halo mass of 10 −10 M , and thus have the sensitivity to probe effects on primordial perturbations at co-moving scales as small as 10 −7 Mpc [89,91].…”
Section: Jhep03(2022)031mentioning
confidence: 99%
“…The ensuing altered predictions of the ionization history as well as of the halo-mass function in the late Universe can be probed with various strategies [81,[86][87][88][89][90]. In particular, future Pulsar Timing Arrays (PTA) will be able to constrain the abundance of local subhalos down to a halo mass of 10 −10 M , and thus have the sensitivity to probe effects on primordial perturbations at co-moving scales as small as 10 −7 Mpc [89,91]. Such a scale corresponds to τ ∼ 10 −6 s, or, conversely, a reheating temperature of T end ∼ 300 MeV following the end of the EMD era.…”
We propose a new mechanism where a multi-component dark sector generates the observed dark matter abundance and baryon asymmetry and thus addresses the coincidence between the two. The thermal freeze-out of dark matter annihilating into meta-stable dark partners sets the dark matter relic abundance while providing the out-of-equilibrium condition for baryogenesis. The meta-stable state triggers baryon asymmetry production by its decay well after the freeze-out and potentially induces a period of early matter domination before its decay. The dark matter and baryon abundances are related through number conservation within the dark sector (cogenesis). The “coincidence” is a natural outcome with GeV- to TeV-scale symmetric dark matter and the dark sector’s interactions with the Standard Model quarks. We present a UV-complete model and explore its phenomenological predictions, including dark matter direct detection signals, LHC signatures of new massive particles with color charges and long-lived particles with displaced vertices, dark matter-induced nucleon conversions, (exotic) dark matter indirect detection signals, and effects on the cosmological matter power spectrum. As a side result, we provide a novel analytical treatment for dark sector freeze-out, which may prove useful in the study of related scenarios.
“…As a result, we generally expect a peak in density perturbations between the two scales, leading to a potentially observable enhancement in the local subhalo abundance. The ensuing altered predictions of the ionization history as well as of the halo-mass function in the late Universe can be probed with various strategies [80,[85][86][87][88][89]. In particular, future Pulsar Timing Arrays (PTA) will be able to constrain the abundance of local subhalos down to a halo mass of 10 −10 M , and thus have the sensitivity to probe effects on primordial perturbations at co-moving scales as small as 10 −7 Mpc [88,90].…”
Section: Modifications To Primordial Density Fluctuationsmentioning
confidence: 99%
“…The ensuing altered predictions of the ionization history as well as of the halo-mass function in the late Universe can be probed with various strategies [80,[85][86][87][88][89]. In particular, future Pulsar Timing Arrays (PTA) will be able to constrain the abundance of local subhalos down to a halo mass of 10 −10 M , and thus have the sensitivity to probe effects on primordial perturbations at co-moving scales as small as 10 −7 Mpc [88,90]. Such a scale corresponds to τ ∼ 10 −6 s, or, conversely, a reheating temperature of T end ∼ 300 MeV following the end of the EMD era.…”
Section: Modifications To Primordial Density Fluctuationsmentioning
We propose a new mechanism where a multi-component dark sector generates the observed dark matter abundance and baryon asymmetry and thus addresses the coincidence between the two. The thermal freeze-out of dark matter annihilating into meta-stable dark partners sets the dark matter relic abundance while providing the out-ofequilibrium condition for baryogenesis. The meta-stable state triggers baryon asymmetry production by its decay well after the freeze-out and potentially induces a period of early matter domination before its decay. The dark matter and baryon abundances are related through number conservation within the dark sector (cogenesis). The "coincidence" is a natural outcome with GeV-to TeV-scale symmetric dark matter and the dark sector's interactions with the Standard Model quarks. We present a UV-complete model and explore its phenomenological predictions, including dark matter direct detection signals, LHC signatures of new massive particles with color charges and long-lived particles with displaced vertices, dark matter-induced nucleon conversions, (exotic) dark matter indirect detection signals, and effects on the cosmological matter power spectrum. As a side result, we provide a novel analytical treatment for dark sector freeze-out, which may prove useful in the study of related scenarios.
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