Interaction In Dark Sector Research Articles

Constraints on Metastable Dark Energy Decaying into Dark Matter

We revisit the proposal that an energy transfer from dark energy into dark matter can be described in field theory by a first order phase transition. We analyze a metastable dark energy model proposed in the literature, using updated constraints on the decay time of a metastable dark energy from recent data. The results of our analysis show no prospects for potentially observable signals that could distinguish this scenario from the ΛCDM. We analyze, for the first time, the process of bubble nucleation in this model, showing that such model would not drive a complete transition to a dark matter dominated phase even in a distant future. Nevertheless, the model is not excluded by the latest data and we confirm that the mass of the dark matter particle that would result from such a process corresponds to the mass of an axion-like particle, which is currently one of the best motivated dark matter candidates. We argue that extensions to this model, possibly with additional couplings, still deserve further attention as it could provide an interesting and viable description for an interacting dark sector scenario based in a single scalar field.

The impact of constrained interacting dark energy on the bound-zone velocity profile

We numerically study the effects of constrained interacting dark energy (CIDER) on the bound-zone velocity profiles around massive dark matter halos. Analyzing the CIDER simulations performed by ref. [1] for three different cases of dark sector coupling (β = 0.03, 0.05 and 0.08) as well as for the standard ΛCDM cosmology (β = 0), we determine the mean peculiar velocity profiles in the bound zones around the friends-of-friends halos with masses larger than M cut = 3 × 1013 h-1 M ⊙ at three redshifts, z = 0, 0.5 and 1. It is found that the universal power-law formula proposed by ref. [2] originally for the ΛCDM case still describes well the bound-zone velocity profiles, V(r), even in the CIDER models. The slope of V(r), turns out to be significantly affected by the CIDER, progressively decreasing as β increases. Meanwhile, the amplitude of V(r) exhibits little dependence on β, which is ascribed to the identical Hubble parameters shared by the ΛCDM and CIDER models in the entire redshift range. Our results imply that the bound-zone velocity slope can break a degeneracy even between the ΛCDM and CIDER models with β ≤ 0.03, which the standard cosmological diagnostics fail to distinguish. We devise a simple analytic formula for the bound-zone slope as a function of β, and prove its validity at all of the three redshifts. It is concluded that the slope of the mean bound-zone peculiar velocity profile should be in principle a powerful probe of dark sector interaction.

Exploring dark forces with multimessenger studies of extreme mass ratio inspirals

The exploration of dark sector interactions via gravitational waves (GWs) from binary inspirals has been a subject of recent interest. We study dark forces using extreme mass ratio inspirals (EMRIs), pointing out two issues of interest. Firstly, the innermost stable circular orbit (ISCO) of the EMRI, which sets the characteristic length scale of the system and hence the dark force range to which it exhibits enhanced sensitivity, probes force mediator masses that complement those studied with supermassive black hole (SMBH) or neutron star binaries. The LISA mission (the proposed μAres detector) will probe mediators with masses m V ∼ 10-16 eV (m V ∼ 10-18 eV), corresponding to ISCOs of 106 M ⊙ (108 M ⊙) central SMBHs. Secondly, while the sensitivity to dark couplings is typically limited by the uncertainty in the binary component masses, independent mass measurements of the central SMBH through reverberation mapping campaigns or the motion of dynamical tracers enable one to break this degeneracy. Our results therefore highlight the necessity for coordinated studies, loosely referred to as “multimessenger”, between future μHz- mHz GW observatories and ongoing and forthcoming SMBH mass measurement campaigns, including OzDES-RM, SDSS-RM, and SDSS-V Black Hole Mapper.

Precision cosmological constraints on atomic dark matter

Atomic dark matter is a simple but highly theoretically motivated possibility for an interacting dark sector that could constitute some or all of dark matter. We perform a comprehensive study of precision cosmological observables on minimal atomic dark matter, exploring for the first time the full parameter space of dark QED coupling and dark electron and proton masses (αD,meD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_{e_D} $$\\end{document},mpD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_{p_D} $$\\end{document}) as well as the two cosmological parameters of aDM mass fraction fD and temperature ratio ξ at time of SM recombination. We also show how aDM can accommodate the (H0, S8) tension from late-time measurements, leading to a better fit than ΛCDM or ΛCDM + dark radiation. Furthermore, including late-time measurements leads to closed contours of preferred ξ and dark hydrogen binding energy. The dark proton mass is seemingly unconstrained. Our results serve as an important new jumping-off point for future precision studies of atomic dark matter at non-linear and smaller scales.

A consistent view of interacting dark energy from multiple CMB probes

We analyze a cosmological model featuring an interaction between dark energy and dark matter in light of the measurements of the Cosmic Microwave Background released by three independent experiments: the most recent data by the Planck satellite and the Atacama Cosmology Telescope, and WMAP (9-year data). We show that different combinations of the datasets provide similar results, always favoring an interacting dark sector with a 95% C.L. significance in the majority of the cases. Remarkably, such a preference remains consistent when cross-checked through independent probes, while always yielding a value of the expansion rate H 0 consistent with the local distance ladder measurements. We investigate the source of this preference by scrutinizing the angular power spectra of temperature and polarization anisotropies as measured by different experiments.

Electron mass variation from dark sector interactions and compatibility with cosmological observations

We investigate the model where electrons and dark matter interact with dark energy through the rolling of a scalar field which comes from extra dimensional theories such as the braneworld theory and Brans-Dicke theory. In this model, dark energy couples to dark matter and electrons, which leads to larger values of the mass energies of dark matter and electrons in the early universe. We also fit our model to the cosmological data. By analyzing the data from Planck, baryon acoustic oscillation (BAO), light curves (Pantheon), and type-Ia supernovae (SH0ES), it can be seen that the Hubble tension is relieved in our model and the coupling parameter prefers a nonzero value with a significance of over $2\ensuremath{\sigma}$.

An An Interacting Dark Energy Model with Nonminimal Derivative Coupling in the Parameterized Post-Friedmannian Framework

We investigation the parameterization of the cosmological model with the nonminimal derivative coupling of a scalar field where gravity is coupled nonminimally with the derivatives of dark energy components in the form of a scalar field. We follow the parameterized post-Friedmannian approach for the interacting dark energy theories. We show how the big number of free functions can be reduced by limiting certain assumptions to a few non-zero coefficients. We only consider the case that the dark sector contains at most second order in time derivatives of the metric and scalar fields. In this paper, we demonstrate their use through an example of the dark sector interactions model and classify them according to the current literature.

Forecast analysis on interacting dark energy models from future generation PICO and DESI missions

ABSTRACT The next-generation cosmic microwave background (CMB) satellite missions are expected to provide robust constraints on a wide range of cosmological parameters with unprecedented precision. But these constraints on the parameters could weaken if we do not attribute dark energy to a cosmological constant. The cosmological models involving interaction between dark energy and dark matter can give rise to comparable energy densities at the present epoch, thereby alleviating the so-called cosmic coincidence problem. In the present paper, we perform a forecast analysis to test the ability of the future generation high-sensitive CMB, and baryon acoustic oscillation (BAO) experiments to constrain phenomenological interacting dark energy models. We consider cosmic variance limited future CMB experiment Probe of Inflation and Cosmic Origins (PICO) along with BAO information from the Dark Energy Spectroscopic Instrument (DESI), to constrain the parameters of the interacting dark sector. Based on the stability of the cosmological perturbations, we consider two possibilities for the interaction scenario. We investigate the impact of both coupling constant and equation of state parameter of dark energy on CMB temperature power spectrum, matter power spectrum, and fσ8. We have used simulated temperature and polarization data from PICO within the multipole ranges (ℓ = 2–4000), and as expected, we do see PICO alone produces better constraints than Planck on the ΛCDM parameters. With the integration of PICO and DESI missions, we observe a significant improvement in the constraints on several cosmological parameters, especially the equation of state parameter of dark energy. However, we note that additional data are required to constrain a small positive coupling constant.

Toward a UV model of kinetic mixing and portal matter. II. Exploring unification in an SU(N) group

If dark matter interacts with the Standard Model (SM) via the $U(1{)}_{D}$ kinetic mixing portal at low energies, it necessitates not only the existence of portal matter particles which carry both dark and SM quantum numbers, but also a possible UV completion into which this $U(1{)}_{D}$ and the SM are both embedded. In earlier work, following a bottom-up approach, we attempted to construct a more unified framework of these SM and dark sector interactions. In this paper, we will instead begin to explore, from the top down, the possibility of the unification of these forces via the decomposition of a grand-unified-theory-like group, $G\ensuremath{\rightarrow}{G}_{\mathrm{SM}}\ifmmode\times\else\texttimes\fi{}{G}_{\mathrm{Dark}}$, where $U(1{)}_{D}$ is now a low-energy diagonal subgroup of ${G}_{\mathrm{Dark}}$ and where the familiar ${G}_{\mathrm{SM}}=SU(5)$ will play the role of a proxy for the conventional $SU(3{)}_{c}\ifmmode\times\else\texttimes\fi{}SU(2{)}_{L}\ifmmode\times\else\texttimes\fi{}U(1{)}_{Y}$ SM gauge group. In particular, for this study it will be assumed that $G=SU(N)$ with $N=6--10$. Although not our main goal, models that also unify the three SM generational structure within this same general framework will also be examined. The possibilities are found to be quite highly constrained by our chosen set of model-building requirements, which are likely too strong when they are employed simultaneously to obtain a successful model framework.

New tests of dark sector interactions from the full-shape galaxy power spectrum

We explore the role of redshift-space galaxy clustering data in constraining non-gravitational interactions between dark energy (DE) and dark matter (DM), for which state-of-the-art limits have so far been obtained from late-time background measurements. We use the joint likelihood for pre-reconstruction full-shape (FS) galaxy power spectrum and post-reconstruction Baryon Acoustic Oscillation (BAO) measurements from the BOSS DR12 sample, alongside Cosmic Microwave Background (CMB) data from \textit{Planck}: from this dataset combination we infer $H_0=68.02^{+0.49}_{-0.60}\,{\rm km}/{\rm s}/{\rm Mpc}$ and the 2$\sigma$ lower limit $\xi>-0.12$, among the strongest limits ever reported on the DM-DE coupling strength $\xi$ for the particular model considered. Contrary to what has been observed for the $\Lambda$CDM model and simple extensions thereof, we find that the CMB+FS combination returns tighter constraints compared to the CMB+BAO one, suggesting that there is valuable additional information contained in the broadband of the power spectrum. We test this finding by running additional CMB-free analyses and removing sound horizon information, and discuss the important role of the equality scale in setting constraints on DM-DE interactions. Our results reinforce the critical role played by redshift-space galaxy clustering measurements in the epoch of precision cosmology, particularly in relation to tests of non-minimal dark sector extensions of the $\Lambda$CDM model.

Observational constraints and predictions of the interacting dark sector with field-fluid mapping

We consider an interacting field theory model that describes the interaction between dark energy-dark matter interaction. Only for a specific interaction term, this interacting field theory description has an equivalent interacting fluid description. For inverse power law potentials and linear interaction function, we show that the interacting dark sector model with field-fluid mapping is consistent with four cosmological data sets — Hubble parameter measurements (Hz), Baryonic Acoustic Oscillation data (BAO), Supernova Type Ia data (SN), and High redshift HII galaxy measurements (HIIG). More specifically, these data sets prefer a negative value of interaction strength in the dark sector and lead to consistent best-fit values of Hubble constant and other cosmological parameters. Having established that this interacting field theory model is consistent with cosmological observations, we obtain quantifying tools to distinguish between the interacting and non-interacting dark sector scenarios. We focus on the variation of the scalar metric perturbed quantities as a function of redshift related to structure formation, weak gravitational lensing, and the integrated Sachs-Wolfe effect. We show that the difference in the evolution becomes significant for z < 20, for all length scales, and the difference peaks at smaller redshift values z < 5. We then discuss the implications of our results for the upcoming missions.

Vacuum stability with radiative Yukawa couplings

We explore the electroweak vacuum stability in the framework of a recently proposed paradigm for the origin of Yukawa couplings. These arise as low energy effective couplings radiatively generated by portal interactions with a hidden, or dark, sector at the one-loop level. Possible tree-level Yukawa couplings are forbidden by a new underlying symmetry, assumed to be spontaneously broken by the vacuum expectation value of a new scalar field above the electroweak scale. As a consequence, the top Yukawa interaction ceases to behave as a local operator at energies above the new sector scale and, therefore, cannot contribute to the running of the quartic Higgs coupling at higher energies. By studying two complementary scenarios, we explicitly show that the framework can achieve the stability of the electroweak vacuum without particular tuning of parameters. The proposed mechanism requires the existence of a dark sector and new portal messenger scalar interactions that, connecting the Standard Model to the dark sector fields, could be tested at the LHC and future collider experiments.

Discovering new forces with gravitational waves from supermassive black holes

Supermassive black hole binary mergers generate a stochastic gravitational wave background detectable by pulsar timing arrays. While the amplitude of this background is subject to significant uncertainties, the frequency dependence is a robust prediction of general relativity. We show that the effects of new forces beyond the Standard Model can modify this prediction and introduce unique features into the spectral shape. In particular, we consider the possibility that black holes in binaries are charged under a new long-range force, and we find that pulsar timing arrays are capable of robustly detecting such forces. Supermassive black holes and their environments can acquire charge due to high-energy particle production or dark sector interactions, making the measurement of the spectral shape a powerful test of fundamental physics.

Dark sector interactions and the curvature of the universe in light of Planck's 2018 data

We investigate the observational viability of a class of interacting dark energy (iDE) models in the light of the latest observations of the Cosmic Microwave Background and type Ia supernovae, and the SH0ES measurement of the current expansion rate H 0. Our analysis explores both the assumptions of a non-zero spatial curvature and a free curvature density, the correlation between the interaction parameter α and H 0, and updates the results reported in [1].The results show that the best-fit of our joint analysis clearly favours a positive interaction, i.e., an energy flux from dark matter to dark energy, with α≈ 0.2, while the non-interacting case, α = 0, is ruled out by more than 3σ confidence level under the flat space assumption. On the other hand, considering a non-zero spatial curvature, we find a significant anti-correlation between the interaction parameter and the universe density curvature, which seems to relax the correlation between the parameters α and H 0, as well as between H 0 and the normalization of the matter power spectrum on scales of 8h -1 Mpc (σ8).Finally, we discuss the influence of considering the SH0ES prior on H 0 in the joint analyses performed, and find thatsuch a choice does not change considerably the standard cosmology predictions but has a significant influence on the results of the iDE model.

Searching for the dark sector in two-body antimuon decay with the polarization of monochromatic positrons

The $\mu^+ \to e^+ X$ decay, where $X$ is a dark sector boson, provides one of the strongest available bounds on the scale of dark sector interactions. The $X$ boson can be an axion or a dark photon. We show that the concurrent determination of the anti-muon and positron polarizations makes possible to distinguish with a confidence level of 99% between the two dark sector portals with as few as 6 observed events in the case of the massless dark photon. Instead, the massive spin-1, dimension 4 dark portal cannot be distinguished from the axion-like case. We also discuss the possibility that the $X$ boson be a massive spin-2 particle.

Gravitational wave signatures from dark sector interactions

We show that the gravitational waves generated by the perturbations of general relativistic black holes can be considered as a direct probe of the existence of dark sector interactions. Working within the framework of Horndeski theory and linear perturbations, we show that dark sector interactions effectively reduce to an interaction charge that influences both scalar and tensor waveforms. Furthermore, we show that the total dark matter field, including the effects of dark sector interactions, satisfies a conservation equation embodying the equivalence principle. We exploit this realization to setup the Regge-Wheeler equation and the coupled Zerilli and scalar wave equations for a Schwarzschild-(anti) de Sitter black hole. We then present numerical integration of the coupled even-parity wave equations for the case of a dark matter particle falling straight down into a Schwarzschild black hole.

Nonparametric reconstruction of interaction in the cosmic dark sector

The possibility of a non-gravitational interaction between the dark matter and the dark energy has been reconstructed using some recent datasets. The crucial aspect is that the interaction is not parametrized at the outset, but rather reconstructed directly from the data in a non-parametric way. The Cosmic Chronometer Hubble data, the Pantheon Supernova compilation of CANDELS and CLASH Multy-Cycle Treasury programs obtained by the HST, and the Baryon Acoustic Oscillation Hubble data have been considered in this work. The widely accepted Gaussian Process is used for the reconstruction. The results clearly indicate that a no interaction scenario is quite a possibility. Also, the interaction, if any, is not really significant at the present epoch. The direction of the flow of energy is clearly from the dark energy to the dark matter which is consistent with the thermodynamic requirement.

Cosmological perturbations in the interacting dark sector: Mapping fields and fluids

There is no unique way to describe the dark energy-dark matter interaction, as we have little information about the nature and dynamics of the dark sector. Hence, in many of the phenomenological dark matter fluid interaction models in the literature, the interaction strength $Q_{\nu}$ in the dark sector is introduced by hand. Demanding that the interaction strength $Q_{\nu}$ in the dark sector must have a field theory description, we obtain a unique form of interaction strength. We show the equivalence between the fields and fluids for the $f(R,\chi)$ model where $f$ is an arbitrary, smooth function of $R$ and classical scalar field $\chi$, which represents dark matter. Up to first order in perturbations, we show that the one-to-one mapping between the \emph{classical} field theory description and the phenomenological fluid description of interacting dark energy and dark matter exists \emph{only} for this unique form of interaction. We then classify the interacting dark energy models considered in the literature into two categories based on the field-theoretic description. We introduce a novel autonomous system and its stability analysis for the general interacting dark sector. We show that the dark-energy dominated epoch occurs earlier than the non-interacting systems for a specific scalar field potential and a range of coupling strengths.

Reconstructing a non-linear interaction in the dark sector with cosmological observations

Abstract In this work we model two non-linear directly interacting scenarios in dark sector of the universe with the dimensionless parameter α and β , which dominate the energy exchange between dark energy and dark matter. The central goal of this investigation is to research the interacting model and discuss the cosmological implications based on the current observational datasets. The class of the interaction is generally characterized by a coupling function Q ∝ H ( z ) ρ x , x denotes the energy density of dark matter or dark energy. The constrained results we obtained indicate that the direct interaction in cosmic dark sector is favored by various observational data and the key effects on CMB power spectrum and linear matter power spectrum appear compared to Λ CDM standard paradigm. Finally, we discuss in depth the effect of different neutrino mass hierarchy on matter power spectrum and the variation of the ratio of CMB temperature power spectrum C l T T and matter power spectrum P ( k ) when the Δ N e f f = N − 3 . 046 from 0.5 to 2, respectively.

Model independent perspectives on coupled dark energy and the swampland

We present a general model-independent approach to study the coupled dark energy and the string Swampland criteria. We show how the dark sector interaction is degenerated with the equation of state of dark energy in the context of the expansion of the Universe. With priors for either of them, the dynamics of dark energy and the dark sector interactions can be reconstructed together with the bounds of the Swampland criteria. Combining cosmic chronometers, baryon acoustic oscillation (BAO), and Type Ia supernovae our results suggest a mild $1 \sigma$ significance of dark sector interactions at low redshift for the coupled quintessence. The Lyman-$\alpha$ BAO at $z=2.34$ leads a $2 \sigma$ signal of nonzero interactions at high redshift. The implications for coupled quintessence are discussed.