arXiv subjects

Chuan-Yang Xing

Publications and source records attributed to Chuan-Yang Xing.

14 recordsLinked to original sources

arXiv2026

Enhanced Rydberg-Atom Superheterodyne Detection of Hidden-Photon Dark Matter on Chips

Although hidden-photon dark matter with masses above $10^{-4}\,\mathrm{eV}$ is well motivated by inflationary production, it remains largely unexplored by terrestrial experiments. Through kinetic mixing, hidden photons induce a weak oscillating electric field above $10\,\mathrm{GHz}$. We propose to amplify this signal using a compact high-frequency distributed cavity and detect it with chip-scale Rydberg-atom superheterodyne spectroscopy. Combining resonant enhancement, large dipole moments of Rydberg atoms, and long-term stable integration, this approach can probe hidden-photon dark matter in the mass range $5 \times 10^{-5}\text{--}7\times 10^{-4}\,\mathrm{eV}$ with sensitivities $3$--$4$ orders of magnitude beyond existing limits.

hep-ph↗

arXiv2026

Dark Matter Attenuation inside the Earth: A Boltzmann Equation Approach

For strongly interacting or boosted dark matter, propagation through the Earth can involve sizable scattering and energy loss, reshaping the underground flux in energy, direction, and normalization. Scattered particles may still fall within the detector acceptance, so the detector-side signal depends on phase-space transport from the Earth's surface to the underground detector. In this work, we formulate this transport problem with the Boltzmann equation. Its integral solution organizes successive scattering effects as a deterministic expansion in scattering orders. We analyze the transport equation in flat-Earth and spherical-Earth geometries, and apply the method to Dirac dark matter with an isoscalar vector interaction. The iterative solution agrees well with the Monte Carlo spectrum.

hep-ph↗

arXiv2026

Macroscopic Quantum Interference in Dark Matter Wave Scattering with MICROSCOPE

Ultralight dark matter behaves as a coherent wave, yet its quantum interference effects of elastic scattering with multiple targets have remained unexplored. We show that the nested test masses of MICROSCOPE realize such an ``interferometer'' for dark-matter wave scattering. Amplitudes from the two concentric cylinders interfere and redistribute the induced force between them. This effect produces unique and rotation-modulated signals set by the target geometry. Developing the theoretical framework and applying it to MICROSCOPE data, we obtain leading constraints on quadratic dark-matter--nucleon coupling for masses $10^{-3}$--$10^{-2}\,$eV, reaching cross sections of order $10^{-52}$ cm$^2$.

hep-ph↗

arXiv2026

A Near-Cutoff Waveguide Haloscope for sub-meV Dark Matter

We propose a near-cutoff parallel-plate waveguide haloscope for sub-meV dark matter. The concept retains the large-area openness of a dish antenna while providing cavity-like field enhancement through slow-wave response and coherent accumulation, without relying on a closed standing-wave resonance. For a copper waveguide, the projected dark photon sensitivity reaches $\varepsilon\simeq2.1\times10^{-15}$ near $m_{A'}\simeq 0.1\,\mathrm{meV}$. With an external magnetic field, the same transducer can approach QCD axion parameter space. The waveguide haloscope highlights a sensitive and scalable route toward future sub-meV bosonic dark matter searches.

hep-ph↗

arXiv2025

Coherence from Randomness: Sub-keV Dark Matter Scattering off Random, Heterogeneous Materials

The sub-keV mass range has long posed a challenge for the direct detection of dark matter via elastic scattering. In this Letter, we propose a new mechanism in which dark matter, assumed to be quadratically coupled to SM particles, scatters from random heterogeneous materials with intrinsic density fluctuations, yielding an enhanced coherent response. This effect can substantially increase the total scattering rate and induce measurable accelerations of the target. Using this idea, we derive new constraints from the MICROSCOPE mission that extend into previously unexplored parameter space for sub-keV dark matter, probing cross sections down to $\sim 4\times10^{-38}\,\mathrm{cm^2}$.

hep-ph↗

arXiv2025

Relativistic Atomic Effects of Dark Matter Electron Scattering

The dark matter scattering with atomic bound electrons is a crucial avenue for exploring the sub-GeV mass range. The commonly used factorization, where atomic effects are encoded in an overall form factor multiplying the free-electron scattering matrix element, is not necessarily true. Especially, the free-electron kinematics and phase space cannot consistently apply for off-shell bound electrons. Starting from the first principles of quantum field theory, we establish a theoretically consistent formalism to account for the atomic effects. By taking the scalar-type interaction as an example, we investigate the difference between the non-relativistic and relativistic calculations to show that the relativistic effects can lead to a $30\% \sim 50\%$ reduction in the scattering phase space and differential cross section. In other words, not just a theoretically consistent formalism for the atomic effects but also relativistic calculation with Dirac equation are necessary.

hep-ph↗

arXiv2025

Torsion Balance Experiments Enable Direct Detection of Sub-eV Dark Matter

Light dark matter with sub-eV masses has a high number density in our galaxy, and its scattering cross section with macroscopic objects can be significantly enhanced by coherence effects. Repeated scattering with a target object can induce a measurable acceleration. Torsion balance experiments with geometric asymmetry are, in principle, capable of detecting such signals. Our analysis shows that existing torsion balances designed to test the Equivalence Principle already place the most stringent constraints on DM-nucleon scattering in the $(10^{-2}, 1)\,$eV mass range.

hep-ph↗

arXiv2025

Detecting the Coupling of Axion Dark Matter to Neutron Spins at Spallation Sources via Rabi Oscillation

We propose a novel detection method for axion dark matter using the Rabi oscillation of neutron spins in beam-based measurements. If axions couple to neutron spins, a background oscillating axion dark matter field would drive transitions between spin-up and spin-down neutron states in a magnetic field when the axion particle energy matches the energy gap between the spin states. The transition can be detected in a double-Stern-Gerlach-type apparatus, with the first splitter producing a pure spin-polarized neutron beam and the second splitter selecting spin-flipped signals. Our approach offers enhanced detection capability for axions within the $10^{-12} - 10^{-10} \,$eV mass window with the capability to surpass the sensitivity of current laboratory experiments.

hep-ph↗

arXiv2024

Detecting meV-Scale Dark Matter via Coherent Scattering with an Asymmetric Torsion Balance

Dark matter with mass in the crossover range between wave dark matter and particle dark matter, around $(10^{-3},\, 10^3)\,$eV, remains relatively unexplored by terrestrial experiments. In this mass regime, dark matter scatters coherently with macroscopic objects. The effect of the coherent scattering greatly enhances the accelerations of the targets that the dark matter collisions cause by a factor of $\sim 10^{23}$. We propose a novel torsion balance experiment with test bodies of different geometric sizes to detect such dark matter-induced acceleration. This method provides the strongest constraints on the scattering cross-section between the dark matter and a nucleon in the mass range $(10^{-3}, 1)\,$eV.

hep-ph↗

arXiv2024

Nuclear Production and Analytic Attenuation of Energetic MeV Solar Dark Matter

We propose a solar production mechanism of MeV dark matter to overcome the energy threshold in direct detection experiments. In particular, the proton and deuteron fussion to ${}^3 \mathrm{He}$ of the $pp$ chain that produces energetic neutrino and gamma photon with 5.5$\,$MeV of energy release can also produce a pair of dark matter particles. Besides, we establish an analytical formalism of using the Boltzmann equation to study the solar attenuation effect on the produced dark matter flux. The projected sensitivity is illustrated with Argon target at the DarkSide-LowMass experiment.

hep-ph↗

arXiv2024

Boosted Dark Matter From Centaurus A and Its Detection

Dark matter can be boosted by high energy particles in astrophysical environments through elastic scattering. We study the production of boosted dark matter via scattering with electrons in the relativistic jet of the closest active galactic nucleus, Centaurus A, and its detection in the Super-Kamiokande experiment. Since there are a huge number of electrons in the jet and dark matter is extremely dense around the supermassive black hole that powers the jet, the number of boosted dark matter is tremendously large. Compared to boosted dark matter from blazars, the dark matter flux from Centaurus A is enhanced due to the proximity of Centaurus A. The constraint on dark matter-electron scattering cross section set by Super-Kamiokande is more stringent, down to $\sim 10^{-36} \, \mathrm{cm}^2$ for $\mathrm{MeV}$ dark matter.

hep-ph↗

arXiv2023

Ultraheavy Atomic Dark Matter Freeze-Out through Rearrangement

Atomic dark matter is usually considered to be produced asymmetrically in the early Universe. In this work, we first propose that the symmetric atomic dark matter can be thermally produced through the freeze-out mechanism. The dominant atom anti-atom annihilation channel is the atomic rearrangement. It has a geometrical cross section much larger than that of elementary fermions. After the atomic formation, this annihilation process further depletes dark matter particles and finally freezes out. To give the observed dark matter relic, the dark atoms are naturally ultraheavy, ranging from $10^6$ to $10^{10} \,\mathrm{GeV}$.

hep-ph↗

arXiv2021

Dark Matter Freeze-out via Catalyzed Annihilation

We present a new paradigm of dark matter freeze-out, where the annihilation of dark matter particles is catalyzed. We discuss in detail the regime that the depletion of dark matter proceeds via $2χ\to 2A'$ and $3A' \to 2χ$ processes, in which $χ$ and $A'$ denote dark matter and the catalyst respectively. In this regime, the dark matter number density is depleted polynomially rather than exponentially (Boltzmann suppression) as in classic WIMPs and SIMPs. The paradigm applies for a secluded weakly interacting dark sector with a dark matter in the $\text{MeV-TeV}$ mass range. The catalyzed annihilation paradigm is compatible with CMB and BBN constraints, with enhanced indirect detection signals.

hep-ph↗

arXiv2021

Softly shifting away from dark matter direct detection

We propose soft breaking mechanism for dark matter (DM) shift symmetry in a class of composite dark matter models, where both DM and the Higgs boson arise as pseudo Nambu-Goldstone bosons from novel strong dynamics. Our mechanism is utilized to suppress the non-derivative portal coupling between the Higgs boson and DM particle, which can evade the stringent bound of current DM direct detection experiments. Otherwise this non-derivative portal coupling would naturally be at the same order of the Higgs quartic, rendering this class of models under severe crisis. For realizing soft breaking mechanism, we introduce vector-like top partners, dubbed as "softons", to restore the shift symmetry of DM in top Yukawa sector, which however is only broken by the softon masses. The portal coupling would automatically vanish as the shift-symmetry-breaking softon masses approach zero. Specifically we present a proof-of-concept model of soft breaking, based on the coset $O(6)/O(5)$ and the simplest fermion embedding, and study its DM phenomenology, where we show a large amount of novel parameter space is opened up by using the soft breaking mechanism.

hep-ph↗