Fifth Force

We introduce a new framework for cosmic acceleration: the Scalar-Cost Dark Energy model. In this approach, dark energy arises not from a cosmological constant but from an energetic cost associated with the expansion of spacetime. This cost is encoded in an additional scalar-field term that remains dormant at high redshift but activates dynamically at late times. The model preserves the ΛCDM background expansion while producing distinct, testable perturbation-level signatures. Specifically, it predicts a ~5% enhancement in the linear growth rate, a ~3-5% increase in weak-lensing shear power at intermediate scales, a ~4% rise in cluster abundance above 10¹⁴ M☉, and a ~0.02 upward shift in S₈-alleviating, though not eliminating, the observed weak-lensing vs. CMB tension. The model is stable (no ghosts, cₛ² > 0), consistent with early-universe constraints, and falsifiable with upcoming large-scale structure surveys.

The suggestion in 1986 of a possible gravity-like ``fifth" fundamental force renewed interest in the question of whether new macroscopic forces are present in nature. Such forces are predicted in many theories which unify gravity with the other known forces, and their presence can be detected by searching for apparent deviations from the predictions of Newtonian gravity. We review the phenomenology behind searches for a ``fifth force", and present a summary of the existing experimental constraints.

I r urdn fr t,c n 0f ,nformatOn us etimated to peage .h Iar r nes1• . o n W d the tim for re.u• wMng. itrutti•On. ,earching exastang datae so ota. co~lletion of information. inluding tii ettios for r•eucing thus burden, to Wa0ntton Hadiquarters iervuas. 7ctO :f r information operation and ReportI. IIS Jetterbon Davis Hghway. Suite Q204. ingto, . V 222024302. a to the Office of Management and Budget. Paperwork Reducion Propeat (0704-011)S Waehington. DC 20503 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE

We develop a falsifiable framework in which the phenomenon attributed to "dark matter" arises from resonant overlap shadows cast by the baryonic sector, of which only ~15% is directly visible (luminous stars, gas, dust). Here a shadow field refers to the non-luminous extension of a baryonic mass's influence-an effective field imprint that emerges from its resonant propagation rather than from new particles. The ~15% visible component is treated as the observational proxy for all baryons, luminous and non-luminous alike. In the Unified Resonant Framework (URF) and Omega Predictive Model (ΩPM), each baryonic source generates a nonlocal, mode-structured extension-its shadow field-whose superposition produces the halo-like mass distributions inferred from galaxy rotation curves and weak gravitational lensing. Mathematically, the shadow density is a convolution of the baryon density with a kernel encoding resonant propagation and geometric screening. The total effective density that sources gravity is then ρ_eff = ρ_b + ρ_shadow. We derive field equations, provide kernel families with tractable Fourier-space forms, obtain closed-form predictions for exponential disks, and outline cross-correlation tests between baryon-overlap maps and lensing convergence. As a direct empirical companion to the Zercon detection program, we define a spectral Overlap Harmonic Index (OHI) and show how cosmogenically forged Zercon detectors can test for ΩPM harmonics tied to baryonic overlap while synthetic controls do not. Clear falsifiers are stated: (i) failure of any positive, causal kernel to fit rotation curves and lensing simultaneously across a representative sample; (ii) absence of sidereal-phase-locked harmonic signals in cosmic Zercons when baryon overlap varies, assuming sufficient sensitivity. The framework converts "missing mass" into a measurable shadow superposition with dual channels-gravitational (metric) and resonant (ΩPM)-and a crisp falsification logic.

The electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force are the four fundamental forces of nature. The Standard Model (SM) succeeded in combining the first three forces to describe the most basic building blocks of matter and govern the universe. Despite the model's great success in resolving many issues in particle physics but still has several setbacks and limitations. The model failed to incorporate the fourth force of gravity. It infers that all fermions and bosons are massless contrary to experimental facts. In addition, the model addresses neither the 95% of the universe's energy of Dark Matter (DM) and Dark Energy (DE) nor the universe's expansion. The Complex Field Theory (CFT) identifies DM and DE as complex fields of complex masses and charges that encompasses the whole universe, and pervade all matter. This presumption resolves the issue of failing to detect DM and DE for the last five decades. The theory also presents a model for the universe's expansion and presumes that every material object carries a fraction of this complex field proportional to its mass. These premises clearly explain the physical nature of the gravitational force and its complex field and pave the way for gravity into the SM. On the other hand, to solve the issue of massless bosons and fermions in the SM, Higgs mechanism introduces a pure and abstractive theoretical model of unimaginable four potentials to generate fictitious bosons as mass donors to fermions and W ± and Z bosons. The CFT in this paper introduces, for the first time, a physical explanation to the mystery of the mass formation of particles rather than Higgs' pure mathematical derivations. The analyses lead to uncovering the mystery of electron-positron production near heavy nuclei and never in a vacuum. In addition, it puts a constraint on Einstein's mass-energy equation that energy can never be converted to mass without the presence of dense dark matter and cannot be true in a vacuum. Furthermore, CFT provides different

All the four fundamental forces of nature have been explained in terms of space time. Coupling constant of grand unification has been defined by space time. The density of space time calculated by 'Siva's classical equation for space time' describes the nature of fundamental force. Thus for all fundamental forces, there exist a separate universe with a separate space time and a separate 'maximum signal velocity'. The transformation has been explained as an expansion of a single universe for which maximum signal velocity is 'velocity of light'. This transformation affects the concept of consciousness. Thus all other forms of space times explained as different forces of nature within the limitations of consciousness. Thus 'Bio-Force' defined as a form of space time like all other fundamental forces and considered as a fifth fundamental force. Consciousness is an affect of interactions of 'Bio-Force'. Coupling Constants for 'gravity' and 'Bio field' have been calculated by space time concept and concerned maximum signal velocities. For other three forces strong force, electromagnetic force and weak forces, the space time has been defined by their coupling constants. All these calculations have been done by one single equation Vd=K. With this equation, space time parameters for all fundamental forces have been explained. The conclusions described grand unification of all five natural forces in a different way which has been extended to 'Bio-Force', an important aspect of consciousness.

All the four fundamental forces of nature have been explained in terms of space time. Coupling constant of grand unification has been defined by space time. The density of space time calculated by 'Siva's classical equation for space time' describes the nature of fundamental force. Thus for all fundamental forces, there exist a separate universe with a separate space time and a separate 'maximum signal velocity'. The transformation has been explained as an expansion of a single universe for which maximum signal velocity is 'velocity of light'. This transformation affects the concept of consciousness. Thus all other forms of space times explained as different forces of nature within the limitations of consciousness. Thus 'Bio-Force' defined as a form of space time like all other fundamental forces and considered as a fifth fundamental force. Consciousness is an affect of interactions of 'Bio-Force'. Coupling Constants for 'gravity' and 'Bio field' have been calculated by space time concept and concerned maximum signal velocities. For other three forces strong force, electromagnetic force and weak forces, the space time has been defined by their coupling constants. All these calculations have been done by one single equation Vd=K. With this equation, space time parameters for all fundamental forces have been explained. The conclusions described grand unification of all five natural forces in a different way which has been extended to 'Bio-Force', an important aspect of consciousness.

We propose a new table-top experimental configuration for the direct detection of dark matter QCD axions in the traditional open mass window 10 -6 eV ma 10 -2 eV using non-perturbative effects in a system with non-trivial spatial topology. Different from most experimental setups found in literature on direct dark matter axion detection, which relies on θ or ∇θ, we found that our system is in principle sensitive to a static θ ≥ 10 -14 and can also be used to set limit on the fundamental constant θQED which becomes the fundamental observable parameter of the Maxwell system if some conditions are met. Furthermore, the proposed experiments can probe entire open mass window 10 -6 eV ma 10 -2 eV with the same design, which should be contrasted with conventional cavitytype experiments being sensitive to a specific axion mass. Connection with Witten effect when the induced electric charge e ′ is proportional to θ and the magnetic monopole becomes the dyon with non-vanishing e ′ = -e θ 2π is also discussed.

In this paper, we analyze the importance of the fields: Yukawa (nuclear level), Bohr (atomic level), Planck (Universe level-non human) and Schwinger (void structure). The interrelations of these fields guarantee the stability of the Universe and matter within. Based on our results published in this journal, we put forward the study of the binding energy of the human brain. We showed that the human mind is the field of consciousness with total energy 10 30 GeV. This consciousness field produces the fifth consciousness force with the range 10 5 km and strength 10 - 47 GeV/fm. The range of the fifth force is of the order of Moon-Earth distance. We argue that the Moon is the mirror (source) of Schumann and consciousness waves.

In real Einstein-Lifts above resp. in radial gravitational-fields over planetary surfaces there appear tidal forces, which causes small deviations from real inertial systems because the Ricci-Tensor in the Lift is not equal to zero, caused by the non-parallelity of the gravity field lines. For these quasiinertial-systems (defined now as QUIS) there can be calculated a relative minimal-seize, which only depends from heigth over and radius of the planetary mass.

Weakly interactive slim particles (WISPs), including the QCD axion, axion-like particles (ALPs), and hidden photons, are considered to be strong candidates for the dark matter carrier particle. The microwave cavity experiment WISPDMX is the first direct WISP dark matter search experiment probing the particle masses in the 0.8-2.0 $\mu$eV range. The first stage of WISPDMX measurements has been completed at nominal resonant frequencies of the cavity. The second stage of WISPDMX is presently being prepared, targeting hidden photons and axions within 60\% of the entire 0.8-2.0 $\mu$eV mass range.

Se propone una hipótesis teórica que vincula estructuras de flujo hidrodinámico en vórtices de Rankine confinados con materiales de topología exótica como el hexaboruro de samario (SmB), planteando la posibilidad de interpretar el eje de succión de un foso resonante como una manifestación análoga a un monopolo gravitacional de naturaleza magneto-topológica. La configuración helicoidal cruzada, al inducir componentes poloidales y toroidales del flujo, genera condiciones de confinamiento axial estable asociables a campos vectoriales con divergencia distinta de cero. Se discuten las implicancias físicas, hidrodinámicas y materiales de esta propuesta, así como su valor heurístico en sistemas de energía renovable basados en hidrodinámica confinada.

Dark photons are particles invoked in some extensions of the Standard Model that could account for at least part of the dark matter content of the Universe. It has been proposed that the production of dark photons in stellar interiors could happen at a rate that depends on both, the dark photon mass and its coupling to Standard Model particles (the kinetic mixing parameter χ). In this work, we aim at exploring the impact of dark photon productions in the stellar core of solar mass red giant branch (RGB) stars during late evolutionary phases. We demonstrate that near the so-called RGB bump, dark photons production may be an energy sink for the star sufficiently significative to modify the extension of the star convective zones. We show that Asteroseismology is able to detect such variations in the structure, allowing us to predict an upper limit of 900 eV and 5 × 10-15 for the mass and kinetic mixing of the dark photons, respectively. We also demonstrate that additional constraints can be derived from the fact that dark photons increase the luminosity of the RGB tip over the current observational uncertainties. This work thus paves the way for an empirical approach to deepen the study of such dark matter particles.

Theories that attempt to explain the observed cosmic acceleration by modifying general relativity all introduce a new scalar degree of freedom that is active on large scales, but is screened on small scales to match experiments. We demonstrate that if such screening occurs via the chameleon mechanism, such as in f (R) theory, it is possible to have order unity violation of the equivalence principle, despite the absence of explicit violation in the microscopic action. Namely, extended objects such as galaxies or constituents thereof do not all fall at the same rate. The chameleon mechanism can screen the scalar charge for large objects but not for small ones (large/small is defined by the depth of the gravitational potential, and is controlled by the scalar coupling). This leads to order one fluctuations in the ratio of the inertial mass to gravitational mass. We provide derivations in both Einstein and Jordan frames. In Jordan frame, it is no longer true that all objects move on geodesics; only unscreened ones, such as test particles, do. In contrast, if the scalar screening occurs via strong coupling, such as in the DGP braneworld model, equivalence principle violation occurs at a much reduced level. We propose several observational tests of the chameleon mechanism: 1. small galaxies should accelerate faster than large galaxies, even in environments where dynamical friction is negligible; 2. voids defined by small galaxies would appear larger compared to standard expectations; 3. stars and diffuse gas in small galaxies should have different velocities, even if they are on the same orbits; 4. lensing and dynamical mass estimates should agree for large galaxies but disagree for small ones. We discuss possible pitfalls in some of these tests. The cleanest is the third one where mass estimate from HI rotational velocity could exceed that from stars by 30% or more. To avoid blanket screening of all objects, the most promising place to look is in voids.

Abstract: An alternative quantization method of local fields was proposed in the papers [1, 2] (cf.:
[3]). In this paper we discuss three cosmological aspects in connection with this quantization
method called quantum local field theory (QLFT).
Aspect 1.: The lowest energy state of the generator of the time translation (the local Hamiltonian),
i.e. its "vacuum state" in this approach, results in a non zero, but finite expectation value, thus it
gives in the Universe a finite but non zero vacuum energy density.
Aspect 2.: The submicroscopic structure of space-time should be studied by analysing the Hawkingradiations
of black holes. If Nature uses a space-time quantum as a new Natural constant then the
analysis of Hawking radiations should display this new constant.
Aspect 3.: One should consider the question: what are the consequences if an Observer in reference
frame L(v=0) wants to transfer in reference frame L(v=V)? Of course one has to accelerate the
Observer to the speed of V. Therefore the acceleration process needs an elementary resolution and
description using an accelerating field of force. Such a force is for example the electromagnetic
field but theoretically it may be the newly discovered fifth force, too. Then one has to answer the
question, at least theoretically, until the direct measurement, if the speed of the action of the fifth
force is equal to the speed of the light or it differs from c? We discuss this question and find that
theoretically it could differ from c, even it could be greater than c. Moreover the discussion admits
the theoretical possibility that the fifth force might need a space of dimension greater the 3.

Indications of a possible composition-dependent fifth force, based on a reanalysis of the Eötvös experiment, have not been supported by a number of modern experiments. Here, we argue that searching for a composition-dependent fifth force necessarily requires data from experiments in which the acceleration differences of three or more independent pairs of test samples of varying composition are determined. We suggest that a new round of fifth-force experiments is called for, in each of which three or more different pairs of samples are compared.

We have reanalyzed data obtained by Potter in a 1923 experiment aimed at testing whether the accelerations of test masses in the Earth's gravitational field are independent of their compositions. Although Potter concludes that the accelerations of his samples compared to a brass standard were individually consistent with a null result, we show that the pattern formed from a combined plot of all of his data suggests the presence of a fifth force coupling to baryon number.

DOI: will be assigned Measurements in the radio regime embrace a number of effective approaches for WISP searches, often covering unique or highly complementary ranges of the parameter space compared to those explored in other research domains. These measurements can be used to search for electromagnetic tracers of the hidden photon and axion oscillations, extending down to ∼ 10 −19 eV the range of the hidden photon mass probed, and closing the last gaps in the strongly favoured 1-5 µeV range for axion dark matter. This provides a strong impetus for several new initiatives in the field, including the WISP Dark Matter eXperiment (WISPDMX) and novel conceptual approaches for broad-band WISP searches in the 0.1-1000 µeV range.

Many theoretically well-motivated extensions of the Standard Model of particle physics predict the existence of the axion and further ultralight axion-like particles. They may constitute the mysterious dark matter in the universe and solve some puzzles in stellar and high-energy astrophysics. There are new, relatively small experiments around the globe, which started to hunt for these elusive particles and complement the accelerator based search for physics beyond the Standard Model.

The division of galaxies into "barred" (SB) and "normal" (S) spirals is a fundamental aspect of the Hubble galaxy classification system. This "tuning fork" view was revised by de Vaucouleurs, whose classification volume recognized apparent "bar strength" (SA, SAB, SB) as a continuous property of galaxies called the "family". However, the SA, SAB, and SB families are purely visual judgments that can have little bearing on the actual bar strength in a given galaxy. Until very recently, published bar judgments were based exclusively on blue light images, where internal extinction or star formation can either mask a bar completely or give the false impression of a bar in a nonbarred galaxy. Near-infrared camera arrays, which principally trace the old stellar population in both normal and barred galaxies, now facilitate a quantification of bar strength in terms of their gravitational potentials and force fields. In this paper, we show that the maximum value, Q b , of the ratio of the tangential force to the mean axisymmetric radial force in a barred disk galaxy is a quantitative measure of the strength of a bar. Q b does not measure bar ellipticity or bar shape, but rather depends on the actual forcing due to the bar embedded in its disk. We show that a wide range of true bar strengths characterizes the category "SB", while de Vaucouleurs category "SAB" corresponds to a much narrower range of bar strengths. We present Q b values for 36 galaxies, and we incorporate our bar classes into a dust-penetrated classification system for spiral galaxies.

A new search strategy for the detection of the elusive dark matter (DM) axion is proposed. The idea is based on streaming DM axions, whose flux might get temporally enormously enhanced due to gravitational lensing. This can happen if the Sun or some planet (including the Moon) is found along the direction of a DM stream propagating towards the Earth location. The experimental requirements to the axion haloscope are a wide-band performance combined with a fast axion rest mass scanning mode, which are feasible. Once both conditions have been implemented in a haloscope, the axion search can continue parasitically almost as before. Interestingly, some new DM axion detectors are operating wide-band by default. In order not to miss the actually unpredictable timing of a potential short duration signal, a network of co-ordinated axion antennae is required, preferentially distributed world-wide. The reasoning presented here for the axions applies to some degree also to any other DM candidates like the WIMPs.

Light scalar fields can drive accelerated expansion of the universe. Hence, scalars are obvious dark energy candidates. To make these models compatible with test of General Relativity in the solar system and fifth force searches on earth, one needs to screen them. One possibility is the chameleon mechanism, which renders an effective mass depending on the local energy density. If chameleons exist, they can be produced in the sun and detected on earth through their radiation pressure. We calculate the solar chameleon spectrum and the sensitivity of an experiment to be carried out at CAST, CERN, utilizing a radiation pressure sensor currently under development at INFN, Trieste. We show, that such an experiment will be sensitive to a wide range of model parameters and signifies a pioneering effort searching for chameleons in unprobed paramterspace.

We consider a nonminimally coupled curvature-matter gravity theory at the Solar System scale. Both a fifth force of Yukawa type and a further non-Newtonian extra force that arises from the nonminimal coupling are present in the solar interior and in the solar atmosphere up to interplanetary space. The extra force depends on the spatial gradient of space-time curvature R. The conditions under which the effects of such forces can be screened by the chameleon mechanism and be made consistent with Cassini measurement of PPN parameter γ are examined. This consistency analysis requires a specific study of Sun's dynamical contribution to the arising forces at all its layers.

We study a theory of gravity in which the action is a result from the general purely disformal transformation on the Einstein-Hilbert action. This theory is a sub-class of GLPV theory which is the the generalization of covariant Galileon. Nevertheless, we find that the self accelerating solution for the background universe disappears in this theory. We also find that, for this theory, the Vainshtein mechanism is absent. However, the Vainshtein mechanism is not necessary for this theory, because this theory can nearly mimic the Einstein theory of gravity at all scales inside the Huble radius without this mechanism.

We review the experimental constraints on additional macroscopic Yukawa forces for interaction ranges below 1 cm, and summarize several theoretical predictions of new forces in this region. An experiment using 1 kHz mechanical oscillators as test masses should be sensitive to much of the parameter space covered by the predictions.

We study spherical collapse in the Quartic and Quintic Covariant Galileon gravity models within the framework of the excursion set formalism. We derive the nonlinear spherically symmetric equations in the quasi-static and weak-field limits, focusing on model parameters that fit current CMB, SNIa and BAO data. We demonstrate that the equations of the Quintic model do not admit physical solutions of the fifth force in high density regions, which prevents the study of structure formation in this model. For the Quartic model, we show that the effective gravitational strength deviates from the standard value at late times (z 1), becoming larger if the density is low, but smaller if the density is high. This shows that the Vainshtein mechanism at high densities is not enough to screen all of the modifications of gravity. This makes halos that collapse at z 1 feel an overall weaker gravity, which suppresses halo formation. However, the matter density in the Quartic model is higher than in standard ΛCDM, which boosts structure formation and dominates over the effect of the weaker gravity. In the Quartic model there is a significant overabundance of high-mass halos relative to ΛCDM. Dark matter halos are also less biased than in ΛCDM, with the difference increasing appreciably with halo mass. However, our results suggest that the bias may not be small enough to fully reconcile the predicted matter power spectrum with LRG clustering data.

This review is a pedagogical introduction to models of gravity and how they are constrained through cosmological observations. We focus on the Horndeski scalar-tensor theory and on the quantities that can be measured with a minimum of assumptions. Alternatives or extensions of general relativity have been proposed ever since its early years. Because of the Lovelock theorem, modifying gravity in four dimensions typically means adding new degrees of freedom. The simplest way is to include a scalar field coupled to the curvature tensor terms. The most general way of doing so without incurring in the Ostrogradski instability is the Horndeski Lagrangian and its extensions. Testing gravity means therefore, in its simplest term, testing the Horndeski Lagrangian. Since local gravity experiments can always be evaded by assuming some screening mechanism or that baryons are decoupled, or even that the effects of modified gravity are visible only at early times, we need to test gravity with cos...

We discuss the problem of constructing models containing an axion and axion-like particles, motivated by astrophysical observations, with decay constants at the intermediate scale ranging from $10^9$GeV to $10^{13}$GeV. We present examples in which the axion and axion-like particles arise accidentally as pseudo Nambu-Goldstone bosons of automatic global chiral symmetries, in models having exact discrete symmetries.

We consider possibilities to grasp and drag one-dimensional solitons in two-component Bose–Einstein condensates (BECs), under the action of gravity, by tweezers induced by spatially confined spin–orbit (SO) coupling applied to the BEC, with the help of focused laser illumination. Solitons of two types are considered, semi-dipoles and mixed modes. We find critical values of the gravity force, up to which the solitons may be held or transferred by the tweezers. The dependence of the critical force on the magnitude and spatial extension of the localized SO interaction, as well as on the soliton’s norm and speed (in the transfer regime), are systematically studied by means of numerical methods, and analytically with the help of a quasi-particle approximation for the soliton. In particular, a noteworthy finding is that the critical gravity force increases with the increase of the transfer speed (i.e., moving solitons are more robust than quiescent ones). Nonstationary regimes are address...

The relation between the activity of cells in the motor cortex and static force has been studied extensively. Most studies have concentrated on the relation to the magnitude of force; this relation is more or less monotonic. The slope of the relation, however, shows considerable variation among different studies and seems to be inversely associated with the range of forces over which the cell activity has been studied. Cells in the motor cortex also show variation in activity with the direction of static force. When both the direction and the magnitude of static force are allowed to vary, a majority of cells show significant changes in activity with direction of force alone, an intermediate number relate to both direction and magnitude, while a small number relate purely to the magnitude. This suggests that the direction of static force can be controlled independently of its magnitude and that this directional signal is especially prominent in the motor cortex. In general, it has been more difficult to study the relations to dynamic force. There is a correlation between motor cortex cell activity and the rate of change of force. The direction of dynamic force is also an important determinant of cell activity. When both static and dynamic force output are required (for example, with arm movement in the presence of gravity) it is the dynamic signal that is most clearly reflected in motor cortex activity. The relations between motor cortex activity and static or dynamic force are not invariant, but may be modified by the behavioral context of the motor output.

When the Abraham Lorentz force is considered in the context of two independently interacting charged particles a surprising consequence arises where particles will feel an Abraham Lorentz force that is creates an attractive force between recoiling particles. When this force is considered in the context of matter-antimatter pairs experiencing each other’s gravitational field, a surprising consequence arises: supergravity. Matter-antimatter pairs will experience and additional attractive force during the recoiling created by the Abraham Lorentz force caused by Coulomb forces between the charged particles. This predicts that the GBAR experiments will measure a freewill constant between matter and antimatter that is higher than what is expected.

The next generation of galaxy surveys will provide highly accurate measurements of the largescale structure of the Universe, allowing for more stringent tests of gravity on cosmological scales. Higher order statistics are a valuable tool to study the non-Gaussianities in the matter field and to break degeneracies between modified gravity and other physical or nuisance parameters. However, understanding from first principles the behaviour of these correlations is essential to characterise deviations from General Relativity (GR), and the purpose of this work. This work uses contemporary ideas of Standard Perturbation Theory on biased tracers to characterize the three point correlation function (3PCF) at tree level for Modified Gravity models with a scale-dependent gravitational strength, and applies the theory to two specific models (f (R) and DGP) that are representative for Chameleon and Vainshtein screening mechanisms. Additionally, we use a multipole decomposition, which apart from speeding up the algorithm to extract the signal from data, also helps to visualize and characterize GR deviations.

A scale invariant model containing dilaton φ and dust (as a model of matter) is studied where the shift symmetry φ → φ + const. is spontaneously broken at the classical level due to intrinsic features of the model. The dilaton to matter coupling "constant" f appears to be dependent of the matter density. In normal conditions, i.e. when the matter energy density is many orders of magnitude larger than the dilaton contribution to the dark energy density, f becomes less than the ratio of the "mass of the vacuum" in the volume occupied by the matter to the Planck mass. The model yields this kind of "Archimedes law" without any especial (intended for this) choice of the underlying action and without fine tuning of the parameters. The model not only explains why all attempts to discover a scalar force correction to Newtonian gravity were unsuccessful so far but also predicts that in the near future there is no chance to detect such corrections in the astronomical measurements as well as in the specially designed fifth force experiments on intermediate, short (like millimeter) and even ultrashort (a few nanometer) ranges. This prediction is alternative to predictions of other known models.

Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark sectors, each with their own beautiful structure, distinct particles, and forces. This review summarizes the physics motivation for dark sectors and the exciting opportunities for experimental exploration. It is the summary of the Intensity Frontier subgroup "New, Light, Weakly-coupled Particles" of the Community Summer Study 2013 (Snowmass). We discuss axions, which solve the strong CP problem and are an excellent dark matter candidate, and their generalization to axion-like particles. We also review dark photons and other dark-sector particles, including sub-GeV dark matter, which are theoretically natural, provide for dark matter candidates or new dark matter interactions, and could resolve outstanding puzzles in particle and astro-particle physics. In many cases, the exploration of dark sectors can proceed with existing facilities and comparatively modest experiments. A rich, diverse, and lowcost experimental program has been identified that has the potential for one or more game-changing discoveries. These physics opportunities should be vigorously pursued in the US and elsewhere.

Dark matter Axion search with riNg Cavity Experiment (DANCE) was proposed. To search for axion-like particles, we aim to detect the rotation and oscillation of optical linear polarization caused by axion-photon coupling with a bow-tie cavity. DANCE can improve the sensitivity to axion-photon coupling constant gaγ for axion mass ma < 10 −10 eV by several orders of magnitude compared to the best upper limits at present. A prototype experiment DANCE Act-1 is in progress to demonstrate the feasibility of the method and to investigate technical noises. We assembled the optics, evaluated the performance of the cavity, and estimated the current sensitivity. If we observe for a year, we can reach gaγ 9 × 10 −7 GeV −1 at ma 10 −13 eV. The current sensitivity was believed to be limited by laser intensity noise at low frequencies and by mechanical vibration at high frequencies.

We obtain constraints on non-Newtonian gravity following from the improved precision measurement of the Casimir force by means of atomic force microscope. The hypothetical force is calculated in experimental configuration (a sphere above a disk both covered by two metallic layers). The strengthenings of constraints up to 4 times comparing the previous experiment and up to 560 times comparing the Casimir force measurements between dielectrics are obtained in the interaction range 5.9 nm≤ λ ≤ 115 nm. Recent speculations about the presence of some unexplained attractive force in the considered experiment are shown to be unjustified.

On large cosmological scales, anisotropic gravitational collapse is manifest in the dark cosmic web. Its statistical properties are little known for alternative dark matter (DM) models such as fuzzy dark matter (FDM). In this work, we assess for the first time the relative importance of cosmic nodes, filaments, walls, and voids in a cosmology with primordial small-scale suppression of power. We post-process N-body simulations of FDM-like cosmologies with varying axion mass m at redshifts z ∼ 1.0−5.6 using the NEXUS+ Multiscale Morphology Filter technique at smoothing scale Δx = 0.04 h−1 Mpc. The formation of wall and void halos is more suppressed than naively expected from the half-mode mass M1/2. Also, we quantify the mass- and volume-filling fractions of cosmic environments and find that 2D cosmic sheets host a larger share of the matter content of the Universe as m is reduced, with an ∼8−12 per cent increase for the m = 7 × 10−22 eV model compared to cold dark matter (CDM). We sh...

On large cosmological scales, anisotropic gravitational collapse is manifest in the dark cosmic web. Its statistical properties are little known for alternative dark matter models such as fuzzy dark matter (FDM). In this work, we assess for the first time the relative importance of cosmic nodes, filaments, walls and voids in a cosmology with primordial small-scale suppression of power. We post-process N-body simulations of FDM-like cosmologies with varying axion mass m at redshifts z ∼ 1.0−5.6 using the NEXUS+ Multiscale Morphology Filter technique at smoothing scale ∆x = 0.04 h −1 Mpc. The formation of wall and void halos is more suppressed than naively expected from the half-mode mass M 1/2. Also, we quantify the mass and volume filling fraction of cosmic environments and find that 2D cosmic sheets host a larger share of the matter content of the Universe as m is reduced, with an ∼ 8−12% increase for the m = 7×10 −22 eV model compared to CDM. We show that in FDM-like cosmologies, filaments, walls and voids are cleaner and more pronounced structures than in CDM, revealed by a strong mid-range peak in the conditioned overdensity PDFs P(δ). At high redshift, low-density regions are more suppressed than high-density regions. Furthermore, skewness estimates S 3 of the total overdensity PDF in FDM-like cosmologies are consistently higher than in CDM, especially at high redshift z ∼ 5.6 where the m = 10 −22 eV model differs from CDM by ∼ 6σ. Accordingly, we advocate for the usage of P(δ) as a testbed for constraining FDM and other alternative dark matter models.

The International Axion Observatory (IAXO) is a forth generation axion helioscope designed to detect solar axions and axion-like particles (ALPs) with a coupling to the photon g aγ down to a few 10 −12 GeV −1 , 1.5 orders of magnitude beyond the current best astrophysical and experimental upper bounds. This range includes parameter values invoked in the context of the observed anomalies in light propagation over astronomical distances and to explain the excessive cooling observed in a number of stellar objects. Here we review the status of the IAXO project and of its potential to probe the most physically motivated regions of the axion/ALPs parameter space.

We present an analysis of the anomalous grawtatlonal attracuon found in the Greenland lcesheet experiment If the anomalous gra&ent ~s due to the existence of a single new, attractive, force, then the force has a range between 225 m and 5 40 km and a couphng constant between 2 4% and 3 5% that ofnewtoman gravity, with a best fit of about 805 m and 3 1%, respectively From our procedure, the chl-squared analysts descrxbmg the quahty of any fit to parameter values can be immediately scaled ffa fractmn of the gravitational anomaly is actually due to densxty anomahes m the bedrock

It is shown that dark matter axions cause an oscillating electric current to flow along magnetic field lines. The oscillating current induced in a strong magnetic field B0 produces a small magnetic field Ba. We propose to amplify and detect Ba using a cooled LC circuit and a very sensitive magnetometer. This appears to be a suitable approach to searching for axion dark matter in the 10 −7 to 10 −9 eV mass range.

The LHAASO Collaboration has reported their observation of very high energy photons (E max γ ≃ 18 TeV) from the gamma-ray burst GRB221009A. The sterile neutrino that involves both mixing and a transition magnetic moment may be a viable explanation for these high energy photon events. However, we demonstrate that such a solution is strongly disfavored by the cosmic microwave background and big bang nucleosynthesis in standard cosmology.

Newtonian simulations are routinely used to examine the matter dynamics on non-linear scales. However, even on these scales, Newtonian gravity is not a complete description of gravitational effects. A post-Friedmann approach shows that the leading-order correction to Newtonian theory is a vector potential in the metric. This vector potential can be calculated from N-body simulations, requiring a method for extracting the velocity field. Here, we present the full details of our calculation of the post-Friedmann vector potential, using the Delaunay Tessellation Field Estimator code. We include a detailed examination of the robustness of our numerical result, including the effects of box size and mass resolution on the extracted fields. We present the power spectrum of the vector potential and find that the power spectrum of the vector potential is ∼10 5 times smaller than the power spectrum of the fully non-linear scalar gravitational potential at redshift zero. Comparing our numerical results to perturbative estimates, we find that the fully non-linear result can be more than an order of magnitude larger than the perturbative estimate on small scales. We extend the analysis of the vector potential to multiple redshifts, showing that this ratio persists over a range of scales and redshifts. We also comment on the implications of our results for the validity and interpretation of Newtonian simulations.

We consider effective model where photons interact with scalar field corresponding to conformal excitations of the internal space (geometrical moduli/gravexcitons). We demonstrate that this interaction results in a modified dispersion relation for photons, and consequently, the photon group velocity depends on the energy implying the propagation time delay effect. We suggest to use the experimental bounds of the time delay of gamma ray bursts (GRBs) photons propagation as an additional constrain for the gravexciton parameters.

During galactic Supernova (SN) explosions, a large amount of feebly interacting particles (FIPs) may be produced. In this work we analyze electrophilic FIPs with masses in the MeV-range that escape from SN and decay into electron-positron pairs, causing an exotic leptonic injection. This contribution adds up to known components, leading to an unexpected excess of X-ray fluxes generated by inverse-Compton scattering of the injected particles on low-energy photon backgrounds. For the first time in the context of FIPs, we use XMM-Newton X-ray measurements to obtain the strongest and most robust bounds on electrophilic FIPs produced by SN in our Galaxy.