Standard Model Photon Research Articles

Fusing photons into nothing, a new search for invisible ALPs and Dark Matter at Belle II

We consider an axion-like particle coupled to the Standard Model photons and decaying invisibly at Belle II. We propose a new search in the e+e− + invisible channel that we compare against the standard γ + invisible channel. We find that the e+e− + invisible channel has the potential to ameliorate the reach for the whole ALP mass range. This search leverages dedicated kinematic variables which significantly suppress the Standard Model background. We explore the implications of our expected reach for Dark Matter freeze-out through ALP-mediated annihilations.

Systematic analysis of search strategies for Lμ − Lτ gauge bosons at Belle II

Extensions of the Standard Model with masses at or below the GeV scale are motivated by searches for dark matter and precision measurements in the quark and lepton flavour sectors, including that of the muon anomalous magnetic moment. An excellent experimental environment to test such light new physics is given by the Belle II experiment, which foresees to take up to 50 ab−1 of data. Here we consider a model with an additional gauged U1Lμ−Lτ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \ extrm{U}{(1)}_{L_{\\mu }-{L}_{\ au }} $$\\end{document} symmetry that introduces a neutral gauge boson, a Dark Photon, with possibly large couplings to muon- and tau-flavored leptons, including neutrinos. Dark Photon mixing with the Standard Model photon is loop induced, allowing it to couple to electrically charged fermions other than muons and taus. We systematically investigate the possible search strategies for Dark Photons with four fermion final states. We identified search channels with muons as the most promising ones, and we analyse the kinematic distributions to obtain cuts that optimise the sensitivity of Belle II searches for the Dark Photon. Summarising the sensitivities from the most promising search channels we provide a comprehensive overview of future searches at Belle II.

Phenomenology of ultralight bosons around compact objects: In-medium suppression

Mixing between ultralight bosons and the Standard Model photon may allow access to the hitherto invisible Universe. In the presence of plasma, photons are dressed with an effective mass which will influence the conversion between the two. We study this phenomenon, known as , in the context of black hole physics. We consider both axion-photon mixing around charged black holes and dark photon-photon mixing around neutral black holes. We find that the presence of plasma indeed influences the conversion rate, possibly quenching it altogether for large plasma densities, and discuss implications for superradiance and observational signatures. Published by the American Physical Society 2024

Dark Photon Limits from Patchy Dark Screening of the Cosmic Microwave Background.

Dark photons that kinetically mix with the Standard Model photon give rise to new spectral anisotropies (patchy dark screening) in the cosmic microwave background (CMB) due to conversion of photons to dark photons within large-scale structure. We utilize predictions for this patchy dark screening signal to provide the tightest constraints to date on the dark photon kinetic mixing parameter [ϵ≲4.5×10^{-8} (95% confidence level)] over the mass range 10^{-13} eV≲m_{A^{'}}≲10^{-11} eV, almost an order of magnitude stronger than previous limits, by applying state-of-the-art component separation techniques to the cross-correlation of Planck CMB and unWISE galaxy survey data.

Bosenovae with quadratically-coupled scalars in quantum sensing experiments

Ultralight dark matter (ULDM) particles of mass mϕ ≲ 1 eV can form boson stars in DM halos. Collapse of boson stars leads to explosive bosenova emission of copious relativistic ULDM particles. In this work, we analyze the sensitivity of terrestrial and space-based experiments to detect such relativistic scalar ULDM particles interacting through quadratic couplings with Standard Model constituents, including electrons, photons, and gluons. We highlight key differences with searches for linear ULDM couplings. Screening of ULDM with quadratic couplings near the surface of the Earth can significantly impact observations in terrestrial experiments, motivating future space-based experiments. We demonstrate excellent ULDM discovery prospects, especially for quantum sensors, which can probe quadratic couplings orders below existing constraints by detecting bosenova events in the ULDM mass range 10−23 eV ≲ mϕ ≲ 10−5 eV. We also report updated constraints on quadratic couplings of ULDM in case it comprises cold DM.

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

Axions and primordial magnetogenesis: the role of initial axion inhomogeneities

The relic density of dark matter in the ΛCDM model restricts the parameter space for a cosmological axion field, constraining the axion decay constant, the initial amplitude of the axion field and the axion mass. It is shown via lattice simulations how the relic density of axion-like particles with masses close to the one of the QCD axion is affected by axion-gauge field interactions and by initial axion inhomogeneities. For pre-inflationary axions, once the Hubble parameter becomes smaller than the axion mass, the latter starts to oscillate, and part of its energy density is spent producing gauge fields via parametric resonance. If the gauge fields are dark photons and Standard Model photons, the energy density of dark photons becomes higher than the one of the axion, while the high conductivity of the primordial plasma damps the oscillations of the photon field. Such a scenario allows for the production of small-scale, primordial magnetic fields, and it is found that the relic density of axions with a low decay constant are within the bounds set by the ΛCDM model, while GUT-scale axions are far too abundant. It is also shown that initial inhomogeneities of the axion field can change substantially the gauge field production, boosting or suppressing (depending on the axion parameters and couplings) the magnetogenesis mechanism with respect to an homogeneous axion field. It is found that when the axion mass is far lighter than the QCD axion model and the initial axion field is inhomogeneous, weak but cosmologically relevant magnetic field seeds can be generated on scales of the order of 0.1 kpc.

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.

Troubles mounting for multipolar dark matter

In this paper, we revisit the experimental constraints on the multipolar dark matter that has derivative coupling to the visible sector mediated by the Standard Model photon. The momentum dependent interaction enables them to be captured efficiently within massive celestial bodies boosted by their steep gravitational potential. This phenomena makes compact celestial bodies as an efficient target to probe such type of dark matter candidates. We demonstrate that a synergy of the updated direct detection results from DarkSide-50 and LUX-ZEPLIN together with IceCube bounds on high energy solar neutrinos from dark matter capture disfavour the viable parameter space of the dipolar dark matter scenario. Whereas, for the anapole dark matter scenario, a narrow window survives that lies within the reach of prospective heating signals due to the capture of dark matter at cold neutron stars.

Calibration of the cryogenic measurement system of a resonant haloscope cavity* *Measurements were performed at Hunan Normal University in Changsha. This work was supported in part by the Scientific Instrument Developing Project of the Chinese Academy of Sciences (YJKYYQ20190049), the International Partnership Program of Chinese Academy of Sciences for Grand Challenges (112311KYSB20210012), the National Natural Science Foundation of China (12074117,

Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities. In this paper, we describe the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor whose operation at a temperature of 22 mK is based on a dilution refrigerator. Our readout system consists of High Electron Mobility Transistors working as cryogenic amplifiers at 4 K, plus room-temperature amplifiers and a spectrum analyzer for signal power detection. We tested the system with a superconducting two-level system based on a single-photon source in the microwave frequency regime. We obtained an overall 95.6 dB system gain and –71.4 dB attenuation in the cavity's input channel. The effective noise temperature of the measurement system is 7.5 K.

Long-baseline quantum sensor network as dark matter haloscope.

Ultralight dark photons constitute a well-motivated candidate for dark matter. A coherent electromagnetic wave is expected to be induced by dark photons when coupled with Standard-Model photons through kinetic mixing mechanism, and should be spatially correlated within the de Broglie wavelength of dark photons. Here we report the first search for correlated dark-photon signals using a long-baseline network of 15 atomic magnetometers, which are situated in two separated meter-scale shield rooms with a distance of about 1700 km. Both the network's multiple sensors and the shields large size significantly enhance the expected dark-photon electromagnetic signals, and long-baseline measurements confidently reduce many local noise sources. Using this network, we constrain the kinetic mixing coefficient of dark photon dark matter over the mass range 4.1 feV-2.1 peV, which represents the most stringent constraints derived from any terrestrial experiments operating over the aforementioned mass range. Our prospect indicates that future data releases may go beyond the astrophysical constraints from the cosmic microwave background and the plasma heating.

Toward UV models of kinetic mixing and portal matter. V. Indirect probes of the new physics scale

Kinetic mixing of the dark photon, the gauge boson of a hidden U(1)D, with the Standard Model (SM) gauge fields to induce an interaction between ordinary matter and dark matter (DM) at 1-loop requires the existence of portal matter (PM) fields having both dark and SM charges. As discussed in earlier work, these same PM fields can also lead to other loop-level mechanisms besides kinetic mixing that can generate significant interactions between SM fermions and the dark photon in a manner analogous to those that can be generated between a Dirac neutrino and a SM photon, i.e., dark moments. In either case, there are reasons to believe, e.g., due to the renormalization group equation running of the U(1)D gauge coupling, that PM fields may have ∼TeV-scale masses that lie at or above those directly accessible to the HL-LHC. If they lie above the reach of the HL-LHC, then the only way to possibly explore the physics at this high scale in the short term is via indirect measurements made at lower energies, e.g., at lepton colliders operating in the mZ to 1 TeV range. In particular, processes such as e+e−→γ+DM or e+e−→f¯f, where f is a SM fermion, may be most useful in this regard. Here we explore these possibilities within the framework of a simple toy PM model, introduced in earlier work, based on a non-Abelian dark gauge group completion operating at the PM scale. In the kinetic mixing setup, we show these efforts fail due to the inherently tiny cross sections in the face of substantial SM backgrounds. However, in the case of interactions via induced dark moments, since they necessarily take the form of higher dimensional operators whose influence grows with energy, we show that access to PM-scale information may become possible for certain ranges of the toy model parameters for both of these e+e− processes at a 1 TeV collider. Published by the American Physical Society 2024

Dark photon production via elastic proton bremsstrahlung with non-zero momentum transfer

We explore hypothetical vector particles, dark photons γ′, which mix with the Standard Model photons and thus mediate interactions with charged particles into the hidden sector. We study the elastic proton bremsstrahlung of dark photons with masses 0.4–1.8 GeV, relevant for direct searches with proton accelerators. A key feature of our calculation is that it explicitly considers the non-zero momentum transfer between protons in the process pp → ppγ′. We compare the obtained differential and full bremsstrahlung cross sections with the results of other authors. Our calculation agrees well (up to 3–9% corrections) with the Weizsacker-Williams approximation that confirms its applicability for proton beams. Then we refine predictions for the dark photon production with proton beams of energy 30 GeV, 70 GeV, 120 GeV and 400 GeV relevant for past, present and future experiments considered in literature.

Search for Dark Photons in Rare Z Boson Decays with the ATLAS Detector.

A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the standard model Z boson is presented, using 139 fb^{-1} of sqrt[s]=13 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}ϵ^{2}, in the dark photon mass range of [5, 40]GeV except for the ϒ mass window [8.8, 11.1]GeV. This search explores new parameter space not previously excluded by other experiments.

Exploring mirror twin Higgs cosmology with present and future weak lensing surveys

We explore the potential of precision cosmological data to study non-minimal dark sectors by updating the cosmological constraint on the mirror twin Higgs model (MTH). The MTH model addresses the Higgs little hierarchy problem by introducing dark sector particles. In this work, we perform a Bayesian global analysis that includes the latest cosmic shear measurement from the DES three-year survey and the Planck CMB and BAO data. In the early Universe, the mirror baryon and mirror radiation behave as dark matter and dark radiation, and their presence modifies the Universe's expansion history. Additionally, the scattering between mirror baryon and photon generates the dark acoustic oscillation process, suppressing the matter power spectrum from the cosmic shear measurement. We demonstrate how current data constrain these corrections to the ΛCDM cosmology and find that for a viable solution to the little hierarchy problem, the proportion of MTH dark matter cannot exceed about 30% of the total dark matter density, unless the temperature of twin photon is less than 30% of that of the standard model photon. While the MTH model is presently not a superior solution to the observed H 0 tension compared to the ΛCDM+ΔN eff model, we demonstrate that it has the potential to alleviate both the H 0 and S 8 tensions, especially if the S 8 tension persists in the future and approaches the result reported by the Planck SZ (2013) analysis. In this case, the MTH model can relax the tensions while satisfying the DES power spectrum constraint up to k ≲ 10 hMpc-1. If the MTH model is indeed accountable for the S 8 and H 0 tensions, we show that the future China Space Station Telescope (CSST) can determine the twin baryon abundance with a 10% level precision.

Search for Dark Photons with Superconducting Radio Frequency Cavities.

We conduct the first "light-shining-through-wall" (LSW) search for dark photons using two state-of-the-art high-quality-factor superconducting radio frequency (SRF) cavities -Dark SRF-and report the results of its pathfinder run. Our new experimental setup enables improvements in sensitivity over previous searches and covers new dark photon parameter space. We design delicate calibration and measurement protocols to utilize the high-Q setup at Dark SRF. Using cavities operating at 1.3GHz, we establish a new exclusion limit for kinetic mixing as small as ε=1.6×10^{-9} and provide the world's best constraints on dark photons in the 2.1×10^{-7}-5.7×10^{-6} eV mass range. Our result is the first proof of concept for the enabling role of SRF cavities in LSW setups, with ample opportunities for further improvements. In addition, our data set a competitive lab-based limit on the standard model photon mass by searching for longitudinal photon polarization.

Probing active-sterile neutrino transition magnetic moments at LEP and CEPC

We consider the sterile neutrino, that is also know as heavy neutral lepton (HNL), interacting with the Standard Model (SM) active neutrino and photon via a transition magnetic moment, the so-called dipole portal, which can be induced from the more general dipole couplings which respect the full gauge symmetries of the SM. Depending on the interactions with ${\rm SU}(2)_L$ and ${\rm U(1)}_Y$ field strength tensors ${\cal W}_{\mu \nu}^a$ and $B^{\mu \nu}$, we consider four typical scenarios and probe the constraints on the couplings with photon $d_\gamma$ at LEP using the analyses to search monophoton signature and the measurement of $Z$ decay. We find that in the considered scenarios assuming the coupling with $Z$ boson $d_Z\neq 0$, the measurement of $Z$ decaying into photon plus invisible particles can provide stricter constraints than the monophoton searches at the LEP1. The complementary constraints to existing experiments can be provided by the LEP. We also investigate the sensitivity on the dipole portal coupling $d_\gamma$ from the monophoton searches at future electron colliders, such as CEPC, and find that CEPC can explore the previously unconstrained parameter space by current experiments.

Solar Radio Emissions and Ultralight Dark Matter

Ultralight axions and dark photons are well-motivated dark matter candidates. Inside the plasma, once the mass of ultralight dark matter candidates equals the plasma frequency, they can resonantly convert into electromagnetic waves, due to the coupling between the ultralight dark matter particles and the standard model photons. The converted electromagnetic waves are monochromatic. In this article, we review the development of using radio detectors to search for ultralight dark matter conversions in the solar corona and solar wind plasma.

Search prospects for axionlike particles at rare nuclear isotope accelerator facilities

We propose a novel experimental scheme, called DAMSA (Dump-produced Aboriginal Matter Searches at an Accelerator), for searching for dark-sector particles, using rare nuclear isotope accelerator facilities that provide high-flux proton beams to produce a large number of rare nuclear isotopes. The high-intensity nature of their beams enables the investigation of dark-sector particles, including axion-like particles (ALPs) and dark photons. By contrast, their typical beam energies are not large enough to produce the backgrounds such as neutrinos resulting from secondary charged particles. The detector of DAMSA is then placed immediate downstream of the proton beam dump to maximize the prompt decay signals of dark-sector particles, which are often challenging to probe in other beam-dump-type experiments featuring a longer baseline, at the expense of an enormous amount of the beam-related neutron (BRN) background. We demonstrate that BRN can be significantly suppressed if the signal accompanies multiple, correlated visible particles in the final state. As an example physics case, we consider ALPs interacting with the Standard Model photon and their diphoton decay signal at DAMSA implemented at a rare nuclear isotope facility similar to the Rare isotope Accelerator complex for ON-line experiment under construction in South Korea. We show that the close proximity of the detector to the ALP production dump makes it possible to probe a high-mass region of ALP parameter space that the existing experiments have never explored.

Implication of the dark axion portal for the EDM of fermions and dark matter probing with NA64e , NA64μ , LDMX, M3 , and BaBar

The link between ordinary Standard Model (SM) photons and both dark photons and axion-like particles (ALPs) can be introduced through the dark axion portal coupling. Given the dark axion portal setup, in the present paper we refer to the dark photon as the mediator between SM and dark matter (DM) particles, implying that it decays predominantly into a pair of DM fermions. Furthermore, we discuss in detail the implication of the dark axion portal scenario for the lepton (electron and muon) fixed-target experiments. In particular, for the specific fixed-target facility we study the missing-energy signatures of the dark photon production followed by its invisible decay into stable DM particles. We investigate the potential to probe dark axion portal vertices with regarding signatures and derive the expected sensitivities of $\mathrm{NA}64e$, $\mathrm{NA}64\ensuremath{\mu}$, LDMX and ${\mathrm{M}}^{3}$. Moreover, we estimate the expected reach of $\mathrm{NA}64e$ from the projected statistics of the $J/\ensuremath{\psi}$ vector meson invisible decays. We also recast the BABAR monophoton bounds for the specific dark axion portal scenario. In addition, we modify the dark axion portal setup by including in the model both the hadron- and lepton-specific ALP couplings. As a result, we obtain the bounds on the combination of fermion-specific couplings of ALP from the fixed-target experiments. We discuss the implication of the modified dark axion portal scenario for the electric dipole moments (EDMs) of SM fermions. In addition, we derive novel constraints on the combination of the $CP$-violating neutron-specific ALP couplings from the existing bounds on neutron EDMs by taking into account the neutron anomalous magnetic moment.