The standard approach to test for deviations from general relativity on cosmological scales is to combine measurements of the growth rate of structure with gravitational lensing. In this study, we show that this method suffers from an important limitation with regard to these two probes: models of dark matter with additional interactions can lead to the very same observational signatures found in modified gravity and vice versa. Using synthetic data of redshift-space distortions, weak lensing, and cosmic microwave background, we demonstrate that this degeneracy is inevitable between modifications of gravity and a dark fifth force. We then show that the coming generation of surveys, in particular the Square Kilometer Array, will allow us to break the degeneracy between such models through measurements of gravitational redshift. Performing a Markov chain Monte Carlo analysis of the synthetic dataset, we quantify the extent to which gravitational redshift can distinguish between two representative classes of models, generalized Brans-Dicke (modified gravity), and coupled quintessence (fifth force).

All of the significant evidence for dark matter observed thus far has been through its gravitational interactions. After 40 years of direct detection experiments, the parameter space for weakly interacting massive particles (WIMPs) as dark matter candidates is rapidly approaching the neutrino floor. Moreover, there have been no signs of WIMPs in any particle production experiments so far. In this light, we consider a dark sector that is strongly decoupled from the visible sector, interacting exclusively through gravity. In this model, proposed by Freese and Winkler [Dark matter and gravitational waves from a dark big bang, Phys. Rev. D 107, 083522 (2023)], dark matter can be produced through a first-order phase transition in the dark sector dubbed “the dark big bang.” We fully determine the allowed region of parameter space for the tunneling potential that leads to the realization of a dark big bang and is consistent with all experimental bounds available.

We construct integrable chiral cosmological models with two scalar fields and potentials represented in terms of hyperbolic functions. Using the conformal transformation of the metric and the corresponding models with induced gravity terms, we obtain the general solutions in the spatially flat, open and closed Friedmann universes and the corresponding integrals of motion. The obtained general solutions can be written in terms of the Jacobi elliptic functions of the conformal time.

The particle nature of dark matter (DM) has been a long-lasting mystery. Many models suggest that DM could decay or self annihilate into standard model particles, and thus could be a source of gamma rays in the sky. The High Altitude Water Cherenkov (HAWC) observatory has yielded some of the strongest limits in searches of DM decay or annihilation. Building on the flux limits provided by the HAWC collaboration in 2018, we consider the effects of additional components from Galactic secondary inverse-Compton scatterings and extragalactic DM distributions. We find that these effects can significantly improve the DM constraints, around a factor of few in some cases. This highlights the importance of considering secondary contributions in detail in LHAASO-WCDA and SWGO in the future.

In the strong magnetic field of a neutron star’s magnetosphere, axions coupled to electromagnetism develop a nonzero probability to convert into photons. Past studies have revealed that the axion-photon conversion can be resonantly enhanced. We recognize that the axion-photon resonance admits two parametrically distinct resonant solutions, which we call the mass-matched resonance and the Euler-Heisenberg assisted resonance. The mass-matched resonance occurs at a point in the magnetosphere where the radially-varying plasma frequency crosses the axion mass ${\omega }_{\mathrm{pl}}\approx m_a$. The Euler-Heisenberg assisted resonance occurs where the axion energy satisfies $\omega \approx (2{\omega }_{\mathrm{pl}}^2/7g_{\gamma \gamma \gamma \gamma }{\overline{B}}^2{)}^{1/2}$. This second resonance is made possible though the strong background magnetic field $\overline{B}$, as well as the nonzero Euler-Heisenberg four-photon self-interaction, which has the coupling $g_{\gamma \gamma \gamma \gamma }=8{\alpha }^2/45m_e^4$. We study the resonant conversion of relativistic axion dark radiation into photons via the Euler-Heisenberg assisted resonance, and we calculate the expected electromagnetic radiation assuming different values for the axion-photon coupling $g_{a\gamma \gamma }$ and different amplitudes for the axion flux onto the neutron star ${\mathrm{\Phi }}_a$. We briefly discuss several possible sources of axion dark radiation. Achieving a sufficiently strong axion flux to induce a detectable electromagnetic signal seems unlikely.

We study single top quark production in association with a lepton-neutrino pair at the LHC within the framework of the Standard Model effective field theory (SMEFT). We focus on relevant two-quark-two-lepton operators ($O_{lq}^3$, $O_{lequ}^1$, and $O_{lequ}^3$). It is known that these operators have tiny effects on the inclusive cross section of standard model tW production and are thus typically ignored in the SMEFT searches. However, we show that by employing smart observables, such as $m_{T2}$, the $\mathrm{pp}\to \mathrm{t}\ell \nu$ process is significantly sensitive to these operators. We set the most stringent limit on the coupling strength of the $O_{lq}^3$ operator by reinterpreting the results of a search for new phenomena with two opposite-charge leptons, jets and missing transverse momentum at $\sqrt{s}=13\mathrm{TeV}$ performed by the ATLAS collaboration. The limits derived on the $O_{lequ}^1$ and $O_{lequ}^3$ operators are comparable to those obtained from probing EFT effects in $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{t}}\ell \nu$ and $\mathrm{pp}\to \mathrm{t}\overline{\mathrm{t}}\ell \ell$ processes at the LHC. Consequently, we propose to include the effects of these three operators on the $\mathrm{pp}\to \mathrm{t}\ell \nu$ process in future global SMEFT analyses to increase the sensitivity and to reduce possible degeneracies.

Ultralight particles are theoretically well-motivated dark matter candidates. In the vicinity of the Solar System, these ultralight particles can be described as a superposition of plane waves, resulting in a stochastic field with sizable amplitude fluctuations on scales determined by the velocity dispersion of dark matter. In this work, we systematically investigate the sensitivity of space-based gravitational-wave interferometers to the stochastic ultralight dark matter field within the frequentist framework. We derive the projected sensitivity of a single detector using the time-delay interferometry. Our results show that space-based gravitational-wave interferometers have the potential to probe unconstrained regions in parameter space and improve the current limit on coupling strengths. Furthermore, we explore the sensitivity of a detector network and investigate the optimal configuration for ultralight dark matter detection. We introduce the overlap reduction function for ultralight dark matter, which quantifies the degree of correlation between the signals observed by different detectors. We find that the configuration, where the signals observed by two detectors are uncorrelated, is the optimal choice for ultralight dark matter detection due to a smaller chance of missing signals. This contrasts with the detection of stochastic gravitational-wave background, where the correlated configuration is preferred. Our results may provide useful insights for potential joint observations involving space-based gravitational-wave detectors like LISA and Taiji, as well as other ultralight dark matter detection networks operating in the coherence limit.

We investigate quantum chromodynamics (QCD) in this study by computing chiral-even generalized parton distributions (GPDs) at twist-3 in the framework of the light-front quark-diquark model, particularly in the zero skewness scenario. We provide a detailed examination of twist-3 chiral-even GPDs, illustrating their behavior through extensive two-dimensional (2-D) and three-dimensional (3-D) visualizations, which demonstrate their dependence on the longitudinal momentum fraction ($x$) and the momentum transfer ($t$). Our investigation also reveals the intricate relationships between these GPDs and other distribution functions such as generalized transverse-momentum dependent distributions, transverse momentum-dependent parton distributions, and parton distribution functions (PDFs). Our study also includes the connected form factors at this twist, which are crucial in understanding the internal structure of hadrons. Additionally, we provide impact parameter-dependent PDF plots to offer insights into the spatial distribution of partons.

The possible link between entanglement and thermalization, and the dynamics of hadronization are addressed by studying the real-time response of the massive Schwinger model coupled to external sources. This setup mimics the production and fragmentation of quark jets, as the Schwinger model and quantum chromodynamics (QCD) share the properties of confinement and chiral symmetry breaking. By using simulations of quantum dynamics on classical hardware, we study the entanglement between the produced jets, and observe the growth of the corresponding entanglement entropy in time. This growth arises from the increased number of contributing eigenstates of the reduced density matrix with sufficiently large and close eigenvalues. We also investigate the physical nature of these eigenstates, and find that at early times they correspond to fermionic Fock states. We then observe the transition from these fermionic Fock states to mesonlike bound states as a function of time. In other words, we observe how hadronization develops in real time. At late times, the local observables at midrapidity (such as the fermion density and the electric field) approach approximately constant values, suggesting the onset of equilibrium and approach to thermalization.

We present a compact formula, expressed in terms of classical polylogarithms up to weight three, for the leading order four-point energy correlator in maximally supersymmetric Yang-Mills theory, in the limit where the four detectors are collinear. This formula is derived by combining a simplified, manifestly dual conformal invariant form of the $1\to 4$ splitting function obtained from the square of the tree-level five-particle form factor of stress-tensor multiplet operators, with a novel integration-by-parts algorithm operating directly on Feynman parameter integrals. Our results provide valuable data for exploring the structure of physical observables in perturbation theory, and for calculations of jet substructure observables in quantum chromodynamics.

In this Letter we revisit general dark matter (DM)-bound-electron interactions studied previously in the influential work [R. Catena et al., Atomic responses to general dark matter-electron interactions, Phys. Rev. Res. 2, 033195 (2020)]. For the most general DM-electron nonrelativistic or relativistic interactions for DM with spin up to 1, we find the average ionization matrix element squared can be organized into three terms, each of which is a product of a DM response function ($a_{0,1,2}$) and a linear combination (${\tilde{W}}_{0,1,2}$) of the four atomic response functions ($W_{1,2,3,4}$) given in that work, ${\tilde{W}}_0=W_1$, ${\tilde{W}}_1=|{\mathit{v}}_0^{\perp }{|}^2{W}_1-2\frac{m_e\mathit{q}·{\mathit{v}}_0^{\perp }}{{\mathit{q}}^2}{W}_2+W_3$, ${\tilde{W}}_2=\frac{(\mathit{q}·{\mathit{v}}_0^{\perp }{)}^2}{{\mathit{q}}^2}{W}_1-2\frac{m_e\mathit{q}·{\mathit{v}}_0^{\perp }}{{\mathit{q}}^2}{W}_2+\frac{m_e^2}{{\mathit{q}}^2}{W}_4$. Furthermore, we find a crucial minus sign was missed for the calculation of $W_2$ in that work, which has significant phenomenological consequences when explaining experimental bounds on specific DM scenarios. Due to the corrected sign, there can be significant cancellations between the $W_2$ and $W_{3,4}$ terms, so that ${\tilde{W}}_{1,2}$ are dominated by the usual response function $W_1$ in some cases. Many DM scenarios involving DM or electron axial-vector current can yield $W_2$ and thus are potentially affected by the sign. As an example, we show that the recent XENON1T constraint on the fermionic DM anapole moment is weakened by a factor of 2 or so. We also present a complete list of NR operators for spin-1 DM and compute their contributions to the DM response functions.

We develop a systematic framework to compute the primordial power spectrum up to next-to-next-to-next to leading order (N3LO) in the Hubble-flow parameters for a large class of effective theories of inflation. We assume that the quadratic action for perturbations is characterized by two time-dependent functions—the kinetic amplitude and the speed of sound—that are independent of the Fourier mode $k$. Using the Green’s function method introduced by Stewart and Gong and extended by Auclair and Ringeval, we determine the primordial power spectrum fully expanded around a pivot scale up to N3LO, starting from a given generic action for perturbations. As a check, we reproduce the state-of-the-art results for scalar and tensor power spectra of the simplest “vanilla” models of single-field inflation. The framework applies to Weinberg’s effective field theory of inflation (with the condition of no parity violation) and to the effective theory of spontaneous de Sitter symmetry breaking. As a concrete application, we provide the expression for the N3LO power spectrum of $R+R^2$ Starobinsky inflation in metric variables, without a field redefinition. All expressions are provided in terms of an expansion in one single parameter, the number of inflationary e-foldings $N_{*}$. Surprisingly, we find that, compared to previous leading-order calculations, for $N_{*}=55$ the N3LO correction results in a 7% decrease of the predicted tensor-to-scalar ratio, in addition to a deviation from the consistency relation and a prediction of a negative running ${\alpha }_{\mathrm{s}}=-\frac{1}{2}(n_{\mathrm{s}}-1{)}^2+\cdots$ of the scalar tilt. These results provide precise theoretical predictions for the next generation of CMB observations.

This paper investigates the trajectories of neutral particles in the Schwarzschild-Melvin spacetime. After reduction by cyclic coordinates this problem reduces to investigating a two-degree-of-freedom Hamiltonian system that has no additional integral. A classification of regions of possible motion of a particle is performed according to the values of the momentum and energy integrals. Bifurcations of periodic solutions of the reduced system are analyzed using a Poincaré map.

We study the weak equivalence principle in the context of modified dispersion relations, a prevalent approach to quantum gravity phenomenology. We find that generic modified dispersion relations violate the weak equivalence principle. The acceleration in general depends on the mass of the test body, unless the Hamiltonian is either 2-homogeneous in the test particles’ 4-momenta or the corresponding Lagrangian differs from the homogeneous case by a total derivative only. The key ingredient of this calculation is a $3+1$ decomposition of the parametrization-invariant relativistic test particle action derived from the dispersion relation. Additionally, we apply a perturbative expansion in the test particle’s spatial velocity and the inverse speed of light. To quantify our result, we provide a general formula for the Eötvós factor of modified dispersion relations. As a specific example, we study the point-particle motion determined from the $\kappa$-Poincaré dispersion relation in the bi-cross-product basis. Comparing the ensuing nonvanishing Eötvós factor to recent data from the MICROSCOPE experiment, we obtain a bound of the model parameter ${\widehat{\mathrm{\Xi }}}^{-1}\ge {10}^{15}\mathrm{GeV}/c^2$.

The criterion for existence of gravitational radiation at conformal infinity in the presence of a positive cosmological constant is applied to a general family of exact solutions representing generic (pairs of) black holes of algebraic type D. Our analysis shows that only accelerating black holes generate gravitational radiation measurable at infinity. This very satisfactory result confirms the goodness of the criterion. To that end, a new metric form of the family of exact type D black holes is constructed—including any cosmological constant and a (double-aligned) non-null electromagnetic field—whose expression is suitable for investigation of the asymptotic structure of this large family of spacetimes. The family depends on seven physical parameters, namely $m$, $a$, $l$, $\alpha$, $e$, $g$, and $\mathrm{\Lambda }$ that characterize mass, specific angular momentum parameter, NUT parameter, acceleration, electric and magnetic charges, and the cosmological constant, respectively.

High fidelity separation of astrophysical foreground contributions from the cosmic microwave background (CMB) signal has been recognized as one of the main challenges of modern CMB data analysis, one that needs to be addressed in a robust way to ensure that the next generation of CMB polarization experiments lives up to its promise. In this work we consider the nonparametric maximum likelihood CMB cleaning approach recently proposed by some of the authors that has been shown to match the performance of standard parametric techniques for simple foreground models, while superseding it in cases where the foregrounds do not exhibit a simple frequency dependence. We present a new implementation of the method in pixel space, extending its functionalities to account for spatial variability of the properties of the foregrounds. We describe the algorithmic details of our approach and its validation against the original code as well as the parametric method for various experimental setups and different models of the foreground components. We argue that the method provides a compelling alternative to other state-of-the-art techniques.

Neutrino flavor instabilities appear to be omnipresent in dense astrophysical environments, thus presenting a challenge to large-scale simulations of core-collapse supernovae and neutron star mergers (NSMs). Subgrid models offer a path forward, but require an accurate determination of the local outcome of such conversion phenomena. Focusing on “fast” instabilities, related to the existence of a crossing between neutrino and antineutrino angular distributions, we consider a range of analytical mixing schemes, including a new, fully three-dimensional one, and also introduce a new machine learning (ML) model. We compare the accuracy of these models with the results of several thousands of local dynamical calculations of neutrino evolution from the conditions extracted from classical NSM simulations. Our ML model shows good overall performance, but struggles to generalize to conditions from a NSM simulation not used for training. The multidimensional analytic model performs and generalizes even better, while other analytic models (which assume axisymmetric neutrino distributions) do not have reliably high performances, as they notably fail as expected to account for effects resulting from strong anisotropies. The ML and analytic subgrid models extensively tested here are both promising, with different computational requirements and sources of systematic errors.

We explore scaling relations for the information carried by individual events, and how that information accumulates in catalogs like those from ground-based gravitational-wave detectors. For a variety of situations, the larger number of quiet/distant signals dominates the overall information over the fewer loud/close sources, independent of how many model parameters are considered. We consider implications for a range of astrophysical scenarios, including calibration uncertainty and standard siren cosmology. However, the large number of additional events obtained by lowering the detection threshold can rapidly increase costs. We introduce a simple analysis that balances the costs of analyzing increasingly large numbers of low information events against retaining a higher threshold and running a survey for longer. With the caveat that precise cost estimates are difficult to determine, current economics favor analyzing low signal-to-noise ratio events. However, the higher detection rates expected for next-generation detectors may argue for a higher signal-to-noise ratio threshold for optimal scientific return.

The attenuation length of the muon content in extensive air showers provides important information regarding the generation and development of air showers. This information can be used not only to improve the description of such showers but also to test fundamental models of hadronic interactions. Using data from the LHAASO-KM2A experiment, the development of the muon content in high-energy air showers was studied. The attenuation length of muon content in the air showers was measured from experimental data in the energy range from 0.3 to 30 PeV using the constant intensity cut method. By comparing the attenuation length of the muon content with predictions from high-energy hadronic interaction models (qgsjet-II-04, sibyll 2.3d, and epos-lhc), it is evident that LHAASO results are significantly shorter than those predicted by the first two models (qgsjet-II-04 and sibyll 2.3d) but relatively close to those predicted by the third model (epos-lhc). Thus, the LHAASO data favor the epos-lhc model over the other two models. The three interaction models confirmed an increasing trend in the attenuation length as the cosmic-ray energy increases.