Light Dark Photon Research Articles

Dark photon constraints from CMB temperature anisotropies

The resonant conversion, within the inter-galactic medium, of regular photons into dark photons amplifies the anisotropy observed in the CMB, thereby imposing stringent constraints on the existence of light dark photons. In this study, we investigate the impact of light dark photons, with masses in the range 3 × 10-15 eV < mA ' < 3 × 10-12 eV on the power spectrum of temperature anisotropies within the cosmic microwave background (CMB) radiation utilizing the state-of-the-art large-volume FLAMINGO cosmological simulations. Our results show that using full Planck data, one can expect the existing constraints on the dark photon mixing parameter in this mass range to improve by an order of magnitude.

Novel search for light dark photon in the forward experiments at the LHC

We propose a novel approach for discovering a light dark photon in the forward experiments at the LHC, including the SND@LHC and the FASER experiments. Assuming the dark photon is lighter than twice the electron mass and feebly interacts with ordinary matter, it is long-lived enough to pass through 100 m of rock in front of the forward experiments and also through the detector targets. However, some portion of them could be converted into an electron-positron pair inside the detector through their interaction with the detector target, leaving an isolated electromagnetic shower as a clear new physics signature of the dark photon. With copiously produced dark photons from neutral pion decays in the forward region of the LHC, we expect to observe sizable events inside the detector. Our estimation shows that more than 10 signal events of the dark photon could be observed in the range of kinetic mixing parameter, 6.2×10-5≲ϵ≲2×10-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$6.2\ imes 10^{-5} \\lesssim \\epsilon \\lesssim 2\ imes 10^{-1}$$\\end{document} and 3×10-5≲ϵ≲2×10-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$3\ imes 10^{-5} \\lesssim \\epsilon \\lesssim 2\ imes 10^{-1}$$\\end{document} for dark photon mass mA′≲\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_{A^\\prime } \\lesssim $$\\end{document} 1 MeV with integrated luminosities of 150 fb-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document} and 3 ab-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document}, respectively.

Schwinger dark matter production

Building on recently constructed inflationary vector dark matter production mechanisms as well as studies of magnetogenesis, we show that an inflationary dark Schwinger mechanism can generate the observed dark matter relic abundance for `dark electron' masses as light as ∼ 0.1 eV and as heavy as 1012 GeV. The dark matter can interact very weakly via the exchange of light dark photons with a power spectrum which is peaked at very small scales, thus evading isocurvature constraints. This mechanism is viable even when (purely) gravitational particle production is negligible. Thus dark matter can be produced solely via the Schwinger effect during inflation including for light masses.

Dark sink enhances the direct detection of freeze-in dark matter

We describe a simple dark sector structure which, if present, has implications for the direct detection of dark matter (DM); . A dark sink transports energy density from the DM into light dark-sector states that do not appreciably contribute to the DM density. As an example, we consider a light, neutral fermion ψ which interacts solely with DM χ via the exchange of a heavy scalar Φ. We illustrate the impact of a dark sink by adding one to a DM freeze-in model in which χ couples to a light dark photon γ′ which kinetically mixes with the Standard Model (SM) photon. This freeze-in model (absent the sink) is itself a benchmark for ongoing experiments. In some cases, the literature for this benchmark has contained errors; we correct the predictions and provide them as a public code. We then analyze how the dark sink modifies this benchmark, solving coupled Boltzmann equations for the dark-sector energy density and DM yield. We check the contribution of the dark sink ψ’s to dark radiation; consistency with existing data limits the maximum attainable cross section. For DM with a mass between MeV−O(10 GeV), adding the dark sink can increase predictions for the direct detection cross section all the way up to the current limits. Published by the American Physical Society 2024

Constraints on photon mass and dark photon from the Jovian magnetic field

The Jovian magnetic field, being the strongest and largest planetary one in the solar system, could offer us new insights into possible microscopic scale new physics, such as a non-zero mass of the Standard Model (SM) photon or a light dark photon kinetically mixing with the SM photon. We employ the immense data set from the latest Juno mission, which provides us unprecedented information about the magnetic field of the gas giant, together with a more rigorous statistical approach compared to the literature, to set strong constraints on the dark photon mass and kinetic mixing parameter, as well as the SM photon mass. The constraint on the dark photon parameters is independent of whether dark photon is (part of) dark matter or not, and serves as the most stringent one in a certain regime of the parameter space.

Constraining dark photons with self-consistent simulations of globular cluster stars

We revisit stellar constraints on dark photons. We undertake dynamical stellar evolution simulations which incorporate the resonant and off-resonant production of transverse and longitudinal dark photons. We compare our results with observables derived from measurements of globular cluster populations, obtaining new constraints based on the luminosity of the tip of the red-giant branch (RGB), the ratio of populations of RGB to horizontal branch (HB) stars (the R-parameter), and the ratio of asymptotic giant branch to HB stars (the R 2-parameter). We find that previous bounds derived from static stellar models do not capture the effects of the resonant production of light dark photons leading to overly conservative constraints, and that they over-estimate the effects of heavier dark photons on the RGB-tip luminosity. This leads to differences in the constraints of up to an order of magnitude in the kinetic mixing parameter.

Dark photon and Axion-like particle search at BESIII

Numerous indirect astronomical and cosmological evidences have suggested the existence of dark matter (DM) in the universe. Its existence provides a strong hint that there may be a dark sector, consisting of particles that do not interact with the known strong, weak, or electromagnetic force. Intriguingly, this dark sector might couple to the Standard Model via portals, which include the possibility of axion-like particle, light Higgs boson, dark photon and spin- 1/2 fermions. BESIII experiment has collected the largest data samples at the J/ψ and ψ(3686) on threshold in the world, which provides a clean reaction environment to search for dark sector and new physics. This proceeding summarizes the recent results in the search of dark photon and axion-like particles published by the BESIII Collaboration.

Peaky production of light dark photon dark matter

We explore a mechanism to produce a light dark photon dark matter through a coupling between the dark photon field and a spectator scalar field which plays no role in the inflationary expansion of the Universe while rolling down its potential during the inflation. The motion of the spectator field efficiently produces dark photons with large wavelengths which become non-relativistic before the time of matter-radiation equality. The spectrum of the wavelengths is peaky so that the constraint from the isocurvature perturbation can be evaded. The correct relic abundance is then achieved over a wide range of the dark photon mass down to 10-13 eV. Our mechanism favors high-scale inflation models which can be tested in future observations. Furthermore, fluctuations of the dark photon field during inflation produce gravitational waves detectable at future space-based interferometers and/or pulsar timing array experiments.

Distortion of neutrino oscillations by dark photon dark matter

A weakly coupled and light dark photon coupling to lepton charges ${L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}$ is an intriguing dark matter candidate whose coherent oscillations alter the dispersion relations of leptons. We study how this effect modifies the dynamics of neutrino flavor conversions, focusing on long baseline and solar oscillations. We analyze data from the T2K, SNO, and Super-Kamiokande experiments in order to obtain world-leading limits on the dark photon gauge coupling for masses below $\ensuremath{\sim}{10}^{\ensuremath{-}11}\text{ }\text{ }\mathrm{eV}$. Degeneracies between shifts in the neutrino mass-squared differences and mixing angles and the new physics effect significantly relax the current constraints on the neutrino vacuum oscillation parameters.

The dark side of the proton

We study the sensitivity of the High-Luminosity LHC to a light baryonic dark photon B, primarily coupled to quarks, as a constituent of the proton. This is achieved by allowing for a dark photon parton distribution function (PDF) in the PDF evolution equations. Depending on the mass and coupling of the dark photon, the evolution of standard quark and gluon PDFs is distorted to varying degrees. By analysing the effect of the dark photon on the tails of Drell-Yan invariant mass distributions, we demonstrate the potential of the LHC in determining competitive bounds on dark photon parameter space.

Singularities in the gravitational capture of dark matter through long-range interactions

We re-examine the gravitational capture of dark matter (DM) through long-range interactions. We demonstrate that neglecting the thermal motion of target particles, which is often a good approximation for short-range capture, results in parametrically inaccurate results for long-range capture. When the particle mediating the scattering process has a mass that is small in comparison to the momentum transfer in scattering events, correctly incorporating the thermal motion of target particles results in a quadratic, rather than logarithmic, sensitivity to the mediator mass, which substantially enhances the capture rate. We quantitatively assess the impact of this finite temperature effect on the captured DM population in the Sun as a function of mediator mass. We find that capture of DM through light dark photons, as in e.g. mirror DM, can bepowerfully enhanced, with self-capture attaining a geometric limit over much of parameter space.For visibly-decaying dark photons, thermal corrections are not large in the Sun, but may be important in understanding long-range DM capture in more massive bodies such as Population III stars. We additionally provide the first calculation of the long-range DM self-evaporation rate.

Sterile neutrino dark matter catalyzed by a very light dark photon

Sterile neutrinos (νs) that mix with active neutrinos (νa) are interesting dark matter candidates with a rich cosmological and astrophysical phenomenology.In their simplest incarnation, their production is severely constrained by a combination of structure formation observations and X-ray searches.We show that if active neutrinos couple to an oscillating condensate of a very light L μ-L τ gauge field, resonant νa-νs oscillations can occur in the early universe, consistent with νsconstituting all of the dark matter, while respecting X-ray constraints onνs→νaγ decays. Interesting deviations from standard solar and atmospheric neutrino oscillations can persist to the present.

Inelastic dark matter, small scale problems, and the XENON1T excess

We study a generic model in which the dark sector is composed of a Majorana dark matter χ1, its excited state χ2, both at the electroweak scale, and a light dark photon Z′ with mz′ ∼ 10−4 eV. The light Z′ enhances the self-scattering elastic cross section χ1χ1 → χ1χ1 enough to solve the small scale problems in the N-body simulations with the cold dark matter. The dark matter communicates with the SM via kinetic mixing parameterized by ϵ. The inelastic scattering process χ1χ1 → χ2χ2 followed by the prompt decay χ2 → χ1Z′ generates energetic Z′. By setting δ ≡ mχ2− mχ1 ≃ 2.8 keV and ϵ ∼ 10−10 the excess in the electron-recoil data at the XENON1T experiment can be explained by the dark-photoelectric effect. The relic abundance of the dark matter can also be accommodated by the thermal freeze-out mechanism via the annihilation χ1χ1(χ2χ2) → Z′Z′ with the dark gauge coupling constant αX ∼ 10−3.

Detecting composite dark matter with long-range and contact interactions in gas clouds

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 multiscatter and overburden analyses to obtain bounds from experiments like CDMS, CRESST, DAMA, XQC, and XENON1T.

Supernova constraints on an axion-photon-dark photon interaction

We present the supernova constraints on an axion-photon-dark photon coupling, which can be the leading coupling to dark sector models and can also lead to dramatic changes to axion cosmology. We show that the supernova bound on this coupling has two unusual features. One occurs because the scattering that leads to the trapping regime converts axions and dark photons into each other. Thus, if one of the two new particles is sufficiently massive, both production and scattering become suppressed and the bounds from bulk emission and trapped (area) emission both weaken exponentially and do not intersection The other unusual feature occurs because for light dark photons, longitudinal modes couple more weakly than transverse modes do. Since the longitudinal mode is more weakly coupled, it can still cause excessive cooling even if the transverse mode is trapped. Thus, the supernova constraints for massive dark photons look like two independent supernova bounds super-imposed on top of each other.

Constraining light dark photons from GW190517_055101 and GW190426_152155

Ultralight dark photons predicted in several Standard Model extensions can trigger the superradiant instability around rotating black holes (BHs) if their Compton wavelength is comparable to the BH radius. Consequently, the angular momentum of the BH is reduced to a value which depends upon the mass and spin of the BH as well as the mass of the dark photon. We use the mass and spin measurements of the primary BHs in two recently observed blackhole binary (BBH) systems, GW190517_055101 and GW190426_152155, to constrain dark photon mass in the ranges $1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}\text{ }\text{ }\mathrm{eV}&lt;{m}_{{A}^{\ensuremath{'}}}&lt;7.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}\text{ }\text{ }\mathrm{eV}$ and $1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}\text{ }\text{ }\mathrm{eV}&lt;{m}_{{A}^{\ensuremath{'}}}&lt;4.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}\text{ }\text{ }\mathrm{eV}$, respectively, assuming a timescale of a few million years from the time of formation of the BBH system to the time of their merger. We also discuss an interesting x-ray binary system, MAXI J1820_070, albeit with a relatively small value of the spin parameter.

Self-interacting hidden sector dark matter, small scale galaxy structure anomalies, and a dark force

The short distance behavior of dark matter (DM) at galaxy scales exhibits several features not explained by the typical cold dark matter (CDM) with velocity-independent cross-section. We discuss a particle physics model with a hidden sector interacting feebly with the visible sector where a dark fermion self-interacts via a dark force with a light dark photon as the mediator. We study coupled Boltzmann equations involving two temperatures, one for each sector. We fit the velocity-dependent DM cross-section to the data from scales of dwarf galaxies to clusters consistent with relic density constraint.

Light dark photon dark matter from inflation

We discuss the possibility of producing a light dark photon dark matter through a coupling between the dark photon field and the inflaton. The dark photon with a large wavelength is efficiently produced due to the inflaton motion during inflation and becomes non-relativistic before the time of matter-radiation equality. We compute the amount of production analytically. The correct relic abundance is realized with a dark photon mass extending down to 10−21 eV.

Dark photon dark matter and fast radio bursts

The nature of dark matter (DM) is still a mystery that may indicate the necessity for extensions of the Standard Model (SM). Light dark photons (DP) may comprise partially or entirely the observed DM density and existing limits for the DP DM parameter space arise from several cosmological and astrophysical sources. In the present work we investigate DP DM using cosmic transients, specifically fast radio bursts (FRBs). The observed time delay of radio photons with different energies have been used to constrain the photon mass or the Weak Equivalence Principle, for example. Due to the mixing between the visible and the DP, the time delay of photons from these cosmic transients, caused by free electrons in the intergalactic medium, can change and impact those constraints from FRBs. We use five detected FRBs and two associations of FRBs with gamma-ray bursts to investigate the correspondent variation on the time delay caused by the presence of DP DM. The result is virtually independent of the FRB used and this variation is very small, considering the still allowed DP DM parameter space, not jeopardizing current bounds on other contributions of the observed time delay.

Dark matter bound state formation in fermionic Z2 DM model with light dark photon and dark Higgs boson

If fermionic dark matter (DM) is stabilized by dark U(1) gauge symmetry that is spontaneously broken into its subgroup Z2, the particle contents of the model becomes very rich: DM and excited DM, both of them are Majorana fermions, as well as two dark force mediators, dark photon and dark Higgs boson are naturally present due to the underlying dark gauge symmetry. In this paper, we study the DM bound state formation processes within this scenario, assuming both dark photon and dark Higgs are light mediators and including the effects of excited DM. The Goldstone boson contributions to the potential matrix in the Schrödinger equations are found to be important. The emissions of a longitudinal vector boson (or somehow equivalently a Goldstone boson) during the DM bound state formations are crucial to induce a significant reannihilation process, reducing the dark matter relic abundance. Most of the stringent constraints for this kind of dark matter considered in the literature are simply evaded.