We present a model of composite Dark Matter (DM), in which a new QCD-like confining "hypercolor" sector generates naturally stable hyperbaryons as DM candidates and at the same time provides mass to new weakly coupled gauge bosons $H$ that serve as DM mediators, coupling the hyperbaryons to the Standard Model (SM) fermions. By an appropriate choice of the $H$ gauge symmetry as a horizontal $SU(2)_h$ SM flavor symmetry, we show how the $H$ gauge bosons can be identified with the horizontal gauge bosons recently put forward as an explanation for discrepancies in rare $B$-meson decays. We find that the mass scale of the $H$ gauge bosons suggested by the DM phenomenology intriguingly agrees with the one needed to explain the rare $B$-decay discrepancies.
Very Heavy and Composite Dark Matter: Theory and Experimental Searches
Arthur B. McDonald Canadian Astroparticle Physics Research Institute（阿瑟·B·麦克唐纳加拿大高能粒子物理研究所）；Queen’s University（女王大学）；Perimeter Institute for Theoretical Physics（基础物理前沿研究所）
The three weak bosons are bound states of two fermions and their antiparticles. There exist also two bound states of three fermions. One of them is neutral and stable. This particle provides the dark matter in our universe.
Composite asymmetric dark matter scenarios naturally explain why the dark matter mass density is comparable with the visible matter mass density. Such scenarios generically require some entropy transfer mechanism below the composite scale; otherwise, their late-time cosmology is incompatible with observations. A tiny kinetic mixing between a dark photon and the visible photon is a promising example of the low-energy portal. In this paper, we demonstrate that grand unifications in the dark and the visible sectors explain the origin of the tiny kinetic mixing. We particularly consider an ultravi…
We construct composite and partially composite Higgs models with complex pseudo-Nambu--Goldstone (pNGB) dark matter states from four-dimensional gauge-Yukawa theories with strongly interacting fermions. The fermions are partially gauged under the electroweak symmetry, and the dynamical electroweak symmetry breaking sector is minimal. The pNGB dark matter particle is stable due to a $\mathrm{U}(1)$ technibaryon-like symmetry, also present in the technicolor limit of the models. However, the relic density is particle anti-particle symmetric and due to thermal freeze-out as opposed to the technic…
The asymmetric dark matter (ADM) scenario solves the baryon-dark matter coincidence problem when the dark matter (DM) mass is of $\mathcal{O}(1)$GeV. Composite ADM models based on QCD-like strong dynamics are particularly motivated since the strong dynamics naturally provides the DM mass of $\mathcal{O}(1)$GeV and the large annihilation cross-section simultaneously. In those models, the sub-GeV dark photon often plays an essential role in transferring the excessive entropy in the dark sector into the visible sector, i.e., the Standard Model sector. This paper constructs a chiral composite ADM …
Asymmetric dark matter (ADM) is an attractive framework relating the observed baryon asymmetry of the Universe to the dark matter density. A composite particle in a new strong dynamics is a promising candidate for ADM as the strong dynamics naturally explains the ADM mass in the GeV range. Its large annihilation cross section due to the strong dynamics leaves the asymmetric component to be dominant over the symmetric component. In such composite ADM scenarios, the dark sector has a relatively large entropy density in the early Universe. The large dark sector entropy results in the overclosure …
The LHC lifetime frontier will probe dark sector in near future, and the visible decay searches at fixed-target experiments have been exploring dark sector. Composite asymmetric dark matter with dark photon portal is a promising framework explaining the coincidence problem between dark matter and visible matter. Dark strong dynamics provides rich structure in the dark sector: the lightest dark nucleon is the dark matter, while strong annihilation into dark pions depletes the symmetric components of the dark matter. Dark photons alleviate cosmological problems. Meanwhile, dark photons make dark…
We study the non-minimal composite Higgs model with global symmetry $\text{SO}(7)$ broken to $\text{SO}(5)\times \text{SO}(2)$. The model results in a composite Two-Higgs doublet model (2HDM) equipped with two extra singlets, the lightest of which can be a viable dark matter candidate. The model is able to reproduce the correct dark matter relic density both via the usual thermal freeze-out and through late time decay of the heavier singlet. In the case of thermal freeze-out, it is possible to evade current experimental constraints even with the minimum fine tuning allowed by electroweak preci…
The goal of this work is to find the simplest UV completions of Accidental Composite Dark Matter models that can dynamically generate an asymmetry for the Dark Matter candidate, the lightest dark baryon, and simultaneously annihilate the symmetric component. In this framework Dark Matter is an accidentally stable bound state of a confining $\mathrm{SU}(N)$ gauge group that can interact weakly with the visible sector. The generation of asymmetry for such candidate happens via the out-of-equilibrium decay of two flavors of a heavy scalar $ϕ$, with mass $M_ϕ> 10^{10}$ GeV. Below such scale, the m…
We consider a chiral gauge theory from which light composite Dirac neutrinos dynamically emerge, augmented by a QCD axion to solve the strong CP problem. We show that an interplay between the composite sector and the axion can also simultaneously lead to successful baryogenesis and generate a correct dark matter abundance via "co-genesis" without contradicting present constraints. We predict $ΔN_{\rm eff} \geq 0.14$ and $m_a$ in the range $O(1)\>{\rm μeV}$--$O(10)\>{\rm meV}$, which can be firmly tested by upcoming CMB experiments and axion searches.
We propose a model which explains the baryon asymmetry of the universe and dark matter relic density at the same time. In this model, dark matter candidate is the dark baryon composed by dark quarks. A scalar mediator, which couples to the standard model leptons and dark quarks, is introduced to generate the asymmetry of baryon and dark baryon simultaneously. Direct detection and collider detection of this model are studied. We find that current underground direct detection experiments and LHC can hardly detect this model. But future lepton colliders, such as CEPC, have great potential to dete…
We present a novel paradigm that allows to define a composite theory at the electroweak scale that is well defined all the way up to any energy by means of safety in the UV. The theory flows from a complete UV fixed point to an IR fixed point for the strong dynamics (which gives the desired walking) before generating a mass gap at the TeV scale. We discuss two models featuring a composite Higgs, Dark Matter and partial compositeness for all SM fermions. The UV theories can also be embedded in a Pati-Salam partial unification, thus removing the instability generated by the $\mbox{U}(1)$ running…
Cold gas clouds recently discovered hundreds of parsecs from the center of the Milky Way Galaxy have the potential to detect dark matter. With a detailed treatment of gas cloud microphysical interactions, we determine Galactic Center gas cloud temperatures, free electron abundances, atomic ionization fractions, heating rates, cooling rates, and find how these quantities vary with metallicity. Considering a number of different dark sector heating mechanisms, we set new bounds on ultra-light dark photon dark matter for masses $10^{-22}-10^{-10}$ eV, vector portal dark matter coupled through a su…
We consider a realisation of composite Higgs models in the context of $SU(6)/ SO(6)$ symmetry, which features a custodial bi-triplet, two Higgs doublets and dark matter candidates. This model can arise from an underlying gauge-fermion theory. The general vacuum structure is explored using the top partial compositeness to generate a special vacuum characterised by a single angle aligned with the first Higgs doublet. We present the CP and Dark Matter $\mathbb{Z}_2$ parity in two different pNGB bases and analyse the spectra in the absence of tadpoles and tachyons. For the phenomenology, we discus…
Scalar singlet dark matter in anomaly-free composite Higgs models is accompanied by exotic particles to which the dark matter annihilates. The latter can therefore freeze out even in the absence of couplings to the Standard Model. In this regime, both current and future direct detection constraints can be avoided. Moreover, due to the different decay modes of the extra particles, the dark matter candidate can even escape indirect detection constraints. Assessing this issue requires dedicated simulations of the gamma ray spectrum, that we provide in the present article in the context of $SO(7)/…
Singlet scalar Dark Matter can naturally arise in composite Higgs models as an additional stable pseudo-Nambu-Goldstone boson. We study the properties of such a candidate in a model based on $SU(6)/SO(6)$, with the light quark masses generated by 4-fermion interactions. The presence of non-linearities in the couplings allows to saturate the relic density for masses $400 < m_{\rm DM} < 1000$ GeV, and survive the bound from Direct Detection and Indirect Detection. The viable parameter regions are in reach of the sensitivities of future upgrades, like XENONnT and LZ.
The LUX-ZEPLIN Event as Hyperfine Spectroscopy of Composite Dark Matter
Kavli IPMU (WPI), UTIAS, University of Tokyo（卡弗里宇宙物理前沿研究所（WPI），多伦多大学应用科学与技术学院，东京大学）；Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma（奥克拉荷马大学霍默·L·道奇物理与天文学系）
I selectively review the theoretical properties and observational limits pertaining to dark atoms, as well as composite dark matter candidates bound by a confining gauge interaction: dark glueballs, glueballinos, mesons and baryons. Emphasis is given to cosmological, direct and indirect detection constraints.
We consider Fraternal Twin Higgs models where the twin bottom quark, $b'$, is much heavier than the twin confinement scale. In this limit aspects of quark bound states, like the mass and binding energy, can be accurately calculated. We show that in this regime, dark matter can be primarily made of twin baryons containing $b' b' b'$ or, when twin hypercharge is gauged, twin atoms, composed of a baryon bound to a twin $τ'$ lepton. We find that there are significant regions of parameter space which are allowed by current constraints but within the realm of detection in the near future. The case w…
We propose a novel mechanism in composite models that provides self-interacting dark matter along with the Higgs itself as composite particles, alleviating the Standard Model naturalness problem and explaining small-scale discrepancies such as the core-cusp and "too big to fail" problems. These dark matter candidates are stable due to global U(1) symmetries of the composite dynamics and their strong self-interactions are created by the novel mechanism based on top-quark partial compositeness. The relic density of the dark matter candidates is particle anti-particle symmetric and due to thermal…
We study the thermodynamic history of composite Dark Matter models. We start with classifying the models by means of the symmetries partially protecting the composite Dark Matter decays and constrain their lifetimes. For each model, we determine the impact of number-changing and number-conserving operators on its thermal history. We also develop the analytic formalism to calculate the asymptotic abundance of stable relics. We show how the relative strength between number-changing and number-conserving interactions together with the dark plasma lifetime affect the thermal fate of the various co…
Large classes of dark sector models feature mass scales and couplings very different from the ones we observe in the Standard Model (SM). Moreover, in the freeze-in mechanism, often employed by the dark sector models, it is also required that the dark sector cannot be populated during the reheating process like the SM. This is the so called asymmetric reheating. Such disparities in sizes and scales often call for dynamical explanations. In this paper, we explore a scenario in which slow evolving conformal field theories (CFTs) offer such an explanation. Building on the recent work on conformal…
Cold interstellar gas clouds provide an exciting new method to discover dark matter. Their immense size makes them uniquely sensitive to interactions from the heaviest, most rarefied dark matter models. Using gas cloud observations, we derive constraints on heavy composite dark matter coupled to the Standard Model through a light dark photon for dark matter up to a thousand solar masses. We find gas clouds are also sensitive to very large composite dark matter that interacts with nuclei through a fixed contact interaction cross section. We also study the contact interaction model and implement…
The Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Department of Physics, Engineering Physics, and Astronomy, Queen’s University（阿瑟·B·麦克唐纳加拿大天体粒子物理研究所，女王大学物理、工程物理和天文学系）；Perimeter Institute for Theoretical Physics（理论物理珀蒂默研究所）；Department of Physics and McDonnell Center for the Space Sciences, Washington University（华盛顿大学物理系和麦克唐纳空间科学中心）；The Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Department of Physics McGill University（阿瑟·B·麦克唐纳加拿大天体粒子物理研究所，麦吉尔大学物理系）
We propose a novel class of composite models that feature both a technicolor and a composite Higgs vacuum limit, resulting in an asymmetric dark matter candidate. These Techni-Composite Higgs models are based on an extended left-right electroweak symmetry with a pseudo-Nambu Goldstone boson Higgs and stable dark matter candidates charged under a global $\mathrm{U}(1)_X$ symmetry, connected to the baryon asymmetry at high temperatures via the $SU(2)_{\rm R}$ sphaleron. We consider, as explicit examples, four-dimensional gauge theories with fermions charged under a new confining gauge group $G_{…
The asymmetric dark matter (ADM) scenario can solve the coincidence problem between the baryon and the dark matter (DM) abundance when the DM mass is of ${\cal O}(1)\,$GeV. In the ADM scenarios, composite dark matter is particularly motivated, as it can naturally provide the DM mass in the ${\cal O}(1)\,$GeV range and a large annihilation cross section simultaneously. In this paper, we discuss the indirect detection constraints on the composite ADM model. The portal operators connecting the $B-L$ asymmetries in the dark and the Standard Model(SM) sectors are assumed to be generated in associat…
Secluded Dark Composites and Remnant Binding Fields
PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics, Johannes Gutenberg University（PRISMA卓越集群与美因茨理论物理研究所，约翰内斯·古腾堡大学）；Perimeter Institute for Theoretical Physics（perimeter理论物理研究所）
Dark Matter could be a composite state of a confining sector with an approximate scale symmetry. We consider the case where the associated pseudo-Goldstone boson, the dilaton, mediates its interactions with the Standard Model. When the confining phase transition in the early universe is supercooled, its dynamics allows for Dark Matter masses up to $10^6$ TeV. We derive the precise parameter space compatible with all experimental constraints, finding that this scenario can be tested partly by telescopes and entirely by gravitational waves.
