In this work, we study the propagation of high energy neutrinos produced in extragalactic sources including the effect of a possible interaction with ultralight axion-like particles (UALP) with a mass $m_a\sim 10^{-22} {\rm eV}$ as the constituents of dark matter (DM) under the assumption that their coupling to neutrinos is dominant. We compute the cross section and describe the propagation of a diffuse neutrino flux using transport equations for each mass eigenstate. This allows us to obtain the neutrino fluxes of the different flavors to be observed at the Earth with neutrino telescopes under different assumptions for the flavor composition emitted at the sources and for a normal ordering (NO) or an inverted ordering (IO) of the neutrino masses. If the coupling of neutrinos with UALPs is the same for all flavors ($g_{νa}$), we find that interactions change the flavor composition of neutrinos arriving on Earth for $g_{νa}\gtrsim 0.5\,{\rm GeV}^{-1}$, causing the electron(muon) flavor to dominate in the NO(IO) case for neutrino energies above $\sim 10^5\,{\rm GeV}$. Although current data on the flavor ratios suggest that interactions with UALP DM do not take place within the range of coupling studied (particularly in the NO case) more data is needed to improve the precision of the experimentally measured flavor composition.
Ultralight scalar and axion dark matter detection with atom interferometers
Shandong University of Aeronautics（山东航空学院）；Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences（中国科学院精密测量科学与技术创新研究院）；University of Chinese Academy of Sciences（中国科学院大学）
We reconsider entropy arguments which have been previously argued to support the idea that the dark matter constituents are primordial black holes with many solar masses. It has recently been shown that QCD axions which solve the strong CP problem may have masses $m_a$ in the extended range $10^{-3}eV > m_a > 10^{-33} eV$. Ultralight axions provide so many degrees of freedom that their entropy can exceed that of primordial black holes. This suggests that ultralight axions are more suited than primordial black holes to be constituents of dark matter.
The ultralight axion with mass around $10^{-22}$ eV is known as a candidate of dark matter. A peculiar feature of the ultralight axion is oscillating pressure in time, which produces oscillation of gravitational potentials. Since the solar system moves through the dark matter halo at the velocity of about $v \sim 300 \, \text{km} / \text{s} = 10^{-3}$, there exists axion wind, which looks like scalar gravitational waves for us. Hence, there is a chance to detect ultralight axion dark matter with a wide mass range by using laser interferometer detectors. We calculate the detector signal induced…
Scenarios with axion-like particles of variable masses, from the milli-eV range to ultralight, can be generated in a natural way in the context of effective field theory models with anomalous $U(1)$ gauge symmetries. They include dimension-5 operators which define a coupling of the axion to the gauge anomaly. They provide a realization, in the domain of ordinary gauge theories, of models for such particles, which evade the usual mass/coupling constraint of ordinary (Peccei-Quinn) axions and are natural dark matter candidates. As an illustration of these models, we present an overview of two of…
Dark gauge sectors and axions are well-motivated in string theory. We demonstrate that if a confining gauge sector gives rise to dark glueballs that are a fraction of the dark matter, and the associated axion has a decay constant near the string scale, then this axion is ultralight and naturally realizes the fuzzy dark matter scenario with a modest tuning of a temperature ratio. Astrophysical observations constrain the size of the glueball component relative to the axionic component, while electric dipole moments constrain mixing with the QCD axion.
Lasing of ultralight axion condensate into photons can be sensitive to the presence of a background plasma owing to its coupling to electromagnetism. Such a scenario is particularly relevant for superradiant axion condensate around stellar mass black holes since the axion mass can be within a few orders of magnitude of the plasma frequency of the surrounding medium. In this paper I discuss the properties of the plasma around a black hole and analyze its effects on the lasing of a uniform axion condensate of mass of the order of the plasma frequency.
If a global chiral symmetry is explicitly broken by anomalies in nonabelian gauge theories, a pseudo Nambu-Goldstone boson (axion) associated with a spontaneous breakdown of such a global symmetry acquires a mass through nonperturbative instanton effects. We calculate the axion mass assuming a supersymmetric SU(2) gauge theory and show that the axion obtains an extremely small mass when the SU(2) gauge symmetry is broken down at very high energy, say at the Planck scale. We identify the axion with a hypothetical ultralight boson field proposed to account for a small but nonzero cosmological co…
Muonium Spectroscopy as a Quantum Sensor for Ultralight Axion Dark Matter
Advanced Energy Science and Technology Guangdong Laboratory（先进能源科学技术广东省实验室）；Institute of Modern Physics, CAS（中国科学院近代物理研究所）；Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University（上海交大李政道研究所与物理天文学院）；University of Liverpool（利物浦大学）；Department of Physics, Jinan University（暨南大学物理系）；State Key Laboratory of Heavy Ion Science and Technology, Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所重离子科学和技术国家重点实验室）；School of Nuclear Science and Technology, University of Chinese Academy of Sciences（中国科学院大学核科学与技术学院）
Detecting axionic dark matter induced electron or nucleon oscillating electric dipole moment (OEDM) has become a new way for dark matter searches. We re-examine such axion-spin couplings in external electromagnetic fields. We point out that axion-photon interaction induces an electron spin effective coupling, which is different from an OEDM. In particular, the axion-spin effective coupling is directly related to magnetic field rather than electric field. For axion-electron or axion-nucleon couplings, an OEDM of fermion is introduced, whose effect in ultralight axion cases depends on whether ax…
We study the ultralight axion dark matter with mass around $10^{-22}$ eV in $f(R)$ gravity which might resolve the dark energy problem. In particular, we focus on the fact that the pressure of the axion field oscillating in time produces oscillations of gravitational potentials. We show that the oscillation of the gravitational potential is sensitive to the model of gravity. Remarkably, we find that the detectability of the oscillation through the gravitational wave detectors can be significantly enhanced due to the nonlinear resonance between the ultralight axion and the scalaron.
We review the physics case for very weakly coupled ultralight particles beyond the Standard Model, in particular for axions and axion-like particles (ALPs): (i) the axionic solution of the strong CP problem and its embedding in well motivated extensions of the Standard Model; (ii) the possibility that the cold dark matter in the Universe is comprised of axions and ALPs; (iii) the ALP explanation of the anomalous transparency of the Universe for TeV photons; and (iv) the axion or ALP explanation of the anomalous energy loss of white dwarfs. Moreover, we present an overview of ongoing and near-f…
Dynamical mechanisms to generate an ultralight axion of mass $\sim 10^{-21}-10^{-22}$ eV in supergravity and strings are discussed. An ultralight particle of this mass provides a candidate for dark matter that may play a role for cosmology at scales $10\, {\rm kpc}$ or less. An effective operator approach for the axion mass provides a general framework for models of ultralight axions, and in one case recovers the scale $10^{-21}-10^{-22}$ eV as the electroweak scale times the square of the hierarchy with an $O(1)$ Wilson coefficient. We discuss several classes of models realizing this framewor…
An ultralight scalar boson with mass $m_1 \simeq 10^{-22}$ eV is gaining credence as a Dark Matter (DM) candidate that explains the dark cores of dwarf galaxies as soliton waves. Such a boson is naturally interpreted as an axion generic in String Theory, with multiple light axions predicted in this context. We examine the possibility of soliton structures over a wide range of scales, accounting for galaxy core masses and the common presence of nuclear star clusters. We present a diagnostic soliton core mass-radius plot that provides a global view, indicating the existence of an additional axio…
We revisit the limit on very light axion-like particles (ALPs) from the absence of gamma rays coincidental with the neutrino burst from SN1987A. We use updated supernova simulations, modern models for the magnetic field inside the Galaxy, and a Primakoff cross section which takes into account proton-degeneracy and mass-reduction effects. We finally give an updated exclusion plot for the electromagnetic coupling of sub-eV ALPs, comparing our new bound with other limits as well as with future ALP searches.
If high-energy neutrinos propagate in a background of ultralight scalar field particles of dark matter ($m_φ\sim 10^{-23}$eV), neutrino-dark matter interactions can play a role and affect the neutrino flux. In this work we analyse this effect using transport equations that account for the neutrino regeneration as well as absorption, and we consider the neutrino flux propagation in the extragalactic medium and also through the galactic halo of dark matter. We show the results for the final flux to arrive on Earth for different cases of point and diffuse neutrino fluxes. {We conclude that this t…
We study how neutrino oscillations could probe the existence of ultralight bosonic dark matter. Three distinct signatures on neutrino oscillations are identified, depending on the mass of the dark matter and the specific experimental setup. These are time modulation signals, oscillation probability distortions due to fast modulations, and fast varying matter effects. We provide all the necessary information to perform a bottom-up, model-independent experimental analysis to probe such scenarios. Using the future DUNE experiment as an example, we estimate its sensitivity to ultralight scalar dar…
A number of proposed and ongoing experiments search for axion dark matter with a mass nearing the limit set by small scale structure (${\cal O} ( 10 ^{ - 21 } {\rm eV} ) $). We consider the late universe cosmology of these models, showing that requiring the axion to have a matter-power spectrum that matches that of cold dark matter constrains the magnitude of the axion couplings to the visible sector. Comparing these limits to current and future experimental efforts, we find that many searches require axions with an abnormally large coupling to Standard Model fields, independently of how the a…
We present a brief overview of a new generation of high-precision laboratory and astrophysical measurements to search for ultralight (sub-eV) axion, axion-like pseudoscalar and scalar dark matter, which form either a coherent condensate or topological defects (solitons). In these new detection methods, the sought effects are linear in the interaction constant between dark matter and ordinary matter, which is in stark contrast to traditional searches for dark matter, where the sought effects are quadratic or higher order in the underlying interaction constants (which are extremely small).
Ultralight axions are theoretically interesting and phenomenologically rich dark sector candidates, but they are difficult to track across cosmological timescales because of their fast oscillations. We resolve this problem by developing a novel method to evolve them efficiently and accurately. We first construct an exact effective fluid which at late times matches the axion but which evolves in a simple way. We then approximate this evolution with a carefully chosen equation of state and sound speed. With our scheme we find that we can obtain subpercent accuracy for the linear theory suppressi…
Enhancing Constraints on Ultralight Axion Dark Matter from Gravitational Capture
University of California Santa Cruz（加州大学圣克鲁兹分校）；Princeton University（普林斯顿大学）；Argonne National Laboratory（阿贡国家实验室）；University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；The University of Tokyo（东京大学）
An ultralight axion around $10^{-23}$ eV is known as a viable dark matter candidate. A distinguished feature of such a dark matter is the oscillating pressure which produces the oscillation of the gravitational potential with frequency in the nano-Hz range. Recently, Khmelnitsky and Rubakov pointed out that this time dependent potential induces the pulse arrival residual and could be observed by the Square Kilometre Array (SKA) experiment. In this paper, we study the detectability of the oscillating pressure of the axion in the framework of $f(R)$ theory, and show that the amplitude of the gra…
Axion particles can form macroscopic condensates, whose size can be galactic in scale for models with very small axion masses $m\sim10^{-22}$ eV, and which are sometimes referred to under the name of Fuzzy Dark Matter. Many analyses of these condensates are done in the non-interacting limit, due to the weakness of the self-interaction coupling of axions. We investigate here how certain results change upon inclusion of these interactions, finding a decreased maximum mass and a modified mass-radius relationship. Further, these condensates are, in general, unstable to decay through number-changin…
We examine the effects of photon-axion mixing on the CMB. We show that if there are very underdense regions between us and the last scattering surface which contain coherent magnetic fields (whose strength can be orders of magnitude weaker than the current bounds), then photon-axion mixing can induce observable deviations in the CMB spectrum. Specifically, we show that the mixing can give rise to non-thermal spots on the CMB sky. As an example we consider the well known CMB cold spot, which according to the Planck data has a weak distortion from a black body spectrum, that can be fit by our mo…
The geodetic and frame-dragging effects are the direct consequences of the spacetime curvature near Earth which can be probed from the Gravity probe B (GP-B) satellite. The satellite result matches quite well with Einstein's general relativistic result. The gyroscope of the satellite which measures the spacetime curvature near Earth contains lots of electrons and nucleons. Ultralight axions, vector gauge bosons, and unparticles can interact with these electrons and nucleons through different spin-dependent and spin-independent operators and change the drift rate of the gyroscope. Some of these…
We present a complete halo model for mixed dark matter composed of cold dark matter (CDM) and ultralight axion-like particles (ULAs). Our model treats ULAs as a biased tracer of CDM, in analogy to treatments of massive neutrinos and neutral hydrogen. The model accounts for clustering of ULAs around CDM host halos, and fully models the cross correlations of both components. The model inputs include the ULA Jeans scale, and soliton density profile. Our model can be used to predict the matter power spectrum, $P(k)$, on non-linear scales for sub-populations of ULAs across the mass range $10^{-33}\…
Ultralight axion-like particles are well-motivated dark matter candidates that are the target of numerous direct detection efforts. In the vicinity of the Solar System, such particles can be treated as oscillating scalar fields. The velocity dispersion of the Milky Way determines a coherence time of about 10^6 oscillations, beyond which the amplitude of the axion field fluctuates stochastically. Any analysis of data from an axion direct detection experiment must carefully account for this stochastic behavior to properly interpret the results. This is especially true for experiments sensitive t…
In the context of structure formation with ultralight axion dark matter, we offer an alternative explanation for the mass relation of solitonic cores and their host halos observed in numerical simulations. Our argument is based entirely on the mass gain that occurs during major mergers of binary cores and largely independent of the initial core-halo mass relation assigned to hosts that have just collapsed. We find a relation between the halo mass $M_h$ and corresponding core mass $M_c$, $M_c\propto M_h^{2β-1}$, where $(1-β)$ is the core mass loss fraction. Following the evolution of core masse…
Gravitational lensing time delays offer an avenue to measure the Hubble parameter $H_0$, with some analyses suggesting a tension with early-type probes of $H_0$. The lensing measurements must mitigate systematic uncertainties due to the mass modelling of lens galaxies. In particular, a core component in the lens density profile would form an approximate local mass sheet degeneracy and could bias $H_0$ in the right direction to solve the lensing tension. We consider ultralight dark matter as a possible mechanism to generate such galactic cores. We show that cores of roughly the required propert…
Ultralight axions (ULAs) are promising dark matter candidates that can have a distinct impact on the formation and evolution of structure on nonlinear scales relative to the cold, collisionless dark matter (CDM) paradigm. However, most studies of structure formation in ULA models do not include the effects of self-interactions, which are expected to arise generically. Here, we study how the tidal evolution of solitons is affected by ULA self-interaction strength and sign. Specifically, using the pseudospectral solver UltraDark.jl, we simulate the tidal disruption of self-interacting solitonic …
Search for Ultralight Axion Dark Matter with a Levitated Ferromagnetic Torsional Oscillator
School of Physics, Hefei University of Technology（合肥工业大学物理学院）；National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University（南京大学固体微结构物理国家重点实验室和物理系）
If all indications for neutrino oscillations observed in the solar, atmospheric neutrino data as well as in the LSND experiments are borne out by the ongoing and future experiments, then they severely constrain the neutrino mass texture. In particular, the need for an ultralight sterile neutrino is hard to avoid. Such ultralight neutrinos have profound implications not only for physics beyond the standard model but also perhaps for physics beyond the conventional grand unification. We discuss a scenario involving a parallel universe that interacts with the familiar universe only via gravitatio…
We perform a detailed analysis on Affleck-Dine leptogenesis taking into account the thermal effects on the dynamics of the flat direction field $ϕ$. We find that an extremely small mass for the lightest neutrino $ν_1$, ${m_ν}_1\lsim 10^{-8}$ eV, is required to produce enough lepton-number asymmetry to explain the baryon asymmetry in the present universe. We impose here the reheating temperature after inflation $T_R$ to be $T_R\lsim 10^8$ GeV to solve the cosmological gravitino problem. The required value of neutrino mass seems to be very unlikely the case since the recent Superkamiokande exper…
We revise the bound from the supernova SN1987A on the coupling of ultralight axion-like particles (ALPs) to photons. In a core-collapse supernova, ALPs would be emitted via the Primakoff process, and eventually convert into gamma rays in the magnetic field of the Milky Way. The lack of a gamma-ray signal in the GRS instrument of the SMM satellite in coincidence with the observation of the neutrinos emitted from SN1987A therefore provides a strong bound on their coupling to photons. Due to the large uncertainty associated with the current bound, we revise this argument, based on state-of-the-ar…
The SRG/eROSITA all-sky survey: Constraints on Ultra-light Axion Dark Matter through Galaxy Cluster Number Counts
Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；Universität Innsbruck, Institut für Astro- und Teilchenphysik（因斯布鲁克大学天体与粒子物理研究所）；INAF, Osservatorio di Astrofisica e Scienza dello Spazio（意大利国家天体物理研究所空间科学与天文观测台）；Department of Physics and Astronomy, Stony Brook University（纽约州立大学石溪分校物理与天文学系）；Universität Hamburg, Hamburger Sternwarte（汉堡大学汉堡天文台）；Department of Physics, National Cheng Kung University（国立成功大学物理系）；IRAP, Université de Toulouse, CNRS, UPS, CNES（图卢兹大学宇宙射线与天体物理学研究所）
