We demonstrate that dark matter (DM) interactions can profoundly influence stellar nucleosynthesis in the early Universe by altering thermodynamic gradients and modifying nuclear reaction rates within primordial stars. Incorporating a DM-modified Fermi-Dirac distribution and accounting for localized energy injection from annihilation heating, our model predicts enhanced production of carbon and nitrogen alongside reduced oxygen synthesis. These compositional shifts significantly reshape stellar structure and produce synthetic spectra that closely reproduce the observed characteristics of carbon-enhanced metal-poor (CEMP) stars. Our findings reveal a direct and previously overlooked role of DM in driving the chemical evolution of the early cosmos, offering a plausible link between fundamental particle physics and observable astrophysical signatures.

The high-density region of the QCD phase diagram displays an intricate competition between color superconductivity and the QCD Kondo effect due to color exchange in quark matter containing a single heavy quark impurity. We explore the characteristic impurity-induced superconducting subgap states arising in such systems by generalizing the surrogate model solver, recently considered in the context of condensed matter physics [Phys. Rev. B 108, L220506 (2023)]. The method consists of approximating the full superconducting bulk by only a small number of effective levels whose parameters are chosen so as to best reproduce the Matsubara frequency dependence of the impurity-bulk hybridization function. We numerically solve a surrogate QCD Kondo model describing a quantum impurity color exchange coupled to a two-color two-flavor superconducting bulk. The results directly indicate the presence of multiple phase transitions as the coupling of the impurity to the bulk is increased, due to the interplay between various overscreened states. The methods introduced here are straightforward enough to be extended to more realistic QCD scenarios.

We explore the advantages of a polarized electron beam at Belle II, as proposed for “Chiral Belle,” in the search for invisibly decaying (dark) bosons that weakly couple to the Standard Model. By measuring the polarization dependence of the production cross section of dark bosons in association with a photon, the dark boson’s spin and Lorentz structure of its couplings can potentially be determined. We analyze the mono-photon channel $e^{+}{e}^{-}\to \gamma +\text{invisible}$ in detail, focusing on the production of an on-shell spin-1 boson. We explore this in the context of three separate scenarios for a new dark vector: a dark photon, a mass-mixed “dark $Z$,” and a vector that couples to right-handed electrons, and we estimate how well the couplings of such bosons to electrons can be constrained in the event of a positive signal.

We present continuum-estimated ($2+1$)-flavor lattice QCD results for the leading-order Taylor expansion coefficients of the equation of state in strong magnetic fields and at nonzero baryon chemical potential. Simulations employ the highly improved staggered quark action with physical pion masses on lattices of temporal extent $N_{\tau }=8$, 12, covering $145\mathrm{MeV}\lesssim T\lesssim 165\mathrm{MeV}$ and $eB\lesssim 0.8{\mathrm{GeV}}^2$, imposing strangeness neutrality with baseline results at electric charge to baryon number ratio $r=0.4$. We determine the $T–eB$ dependence of $q_1$ and $s_1$ (electric charge and strangeness chemical potential ratios), pressure coefficient $P_2$, baryon number density coefficient $N_1^{\mathrm{B}}$, and energy-related coefficients ${\mathrm{\Theta }}_2$ (trace anomaly), ${\epsilon }_2$ (energy density), and ${\sigma }_2$ (entropy density). Magnetic fields induce temperature-band crossings for $q_1$ and $P_2$ and nonmonotonic structures in the energy-related coefficients, with ${\mathrm{\Theta }}_2$ at strong fields possibly vanishing or turning negative at higher $T$, indicating dominance of the pressure term over the energy contribution. We also examine the $r$-dependence, finding that $r=0$ (charge-neutral matter) shows the most muted magnetic-field enhancement of $P_2$ despite larger $|q_1|$, providing a useful reference for neutron-star–relevant conditions. Comparisons with the hadron resonance gas model show qualitative agreement at low $T$ and weak $eB$, with clear deviations near the crossover and at strong fields. These results provide useful input for constraining models and effective theories of QCD matter in strong magnetic fields at finite baryon density.

We study the effect of rotation on the confining and chiral properties of QCD using the Polyakov-enhanced linear sigma model coupled to quarks. Working in the homogeneous approximation, we obtain the phase diagram at finite temperature, baryon density, and angular frequency, taking into account the causality constraint enforced by the spectral boundary conditions at a cylindrical surface. We explicitly address various limits with respect to system size $R$, angular frequency $\mathrm{\Omega }$, and chemical potential $\mu$. We demonstrate that, in this model, the critical temperatures of both the chiral restoration and the deconfinement transitions diminish in response to the increasing rotation, being in contradiction with the first-principle lattice results. We demonstrate that consistency between the thermodynamics of the model and the Tolman-Ehrenfest law is achieved in the limit of large volume. We also compute the mechanical characteristics of the rotating plasma, such as the moment of inertia and the $K_n$ shape coefficients describing the response of the thermodynamic potential with respect to the increase of angular velocity $\mathrm{\Omega }$.

We investigate the photon structure functions via the photon-photon and photon-vector meson scattering within the framework of holographic QCD, focusing on the small Bjorken $x$ region and assuming that the Pomeron exchange dominates. The quasireal photon structure functions are formulated as the convolution of the known U(1) vector field wave function with the Brower-Polchinski-Strassler-Tan (BPST) Pomeron exchange kernel in the five-dimensional AdS space. Assuming the vector meson dominance, the photon structure functions can be calculated in a different way with the BPST kernel and vector meson gravitational form factor, which can be obtained in a bottom-up AdS/QCD model, for the Pomeron-vector meson coupling. It is shown that the obtained $F_2$ structure functions in the both ways agree with the experimental data, which implies the realization of the vector meson dominance within the present model setup. Calculations for the longitudinal structure function and the longitudinal-to-transverse ratio are also presented.

We compute the inclusive $D^0$ production cross section in ultraperipheral Pb-Pb collisions at the LHC as a function of the $D^0$ transverse momentum and rapidity. These calculations are carried out within the new generalized photon-nucleus FONLL ($\mathrm{G}\gamma \mathrm{A}\text{−}\mathrm{FONLL}$) framework, which can predict photonuclear cross sections for charm and beauty hadrons in electron-proton, electron-nucleus, and ultraperipheral heavy-ion collisions. The framework relies on fixed-order next-to-leading logarithm (FONLL) to model heavy-quark production in photonuclear collisions and employs a photon-flux reweighting procedure to describe the production cross sections in ultraperipheral heavy-ion collisions. The $\mathrm{G}\gamma \mathrm{A}$ calculations are first validated against the photoproduction cross sections of $D^{*}$ in electron-proton collisions at HERA. The predictions for the $D^0$ production cross section in ultraperipheral Pb-Pb collisions at the LHC are then presented and compared to the first experimental results obtained by CMS at $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}=5.36\mathrm{TeV}$. The predictions are benchmarked against different choices of nuclear parton distribution functions, fragmentation functions, and renormalization and factorization scales.

Supernova shocks can boost dark matter (DM) particles to high, yet nonrelativistic, velocities, providing a suitable mechanism for analysis within the framework of the nonrelativistic effective field theory (NREFT). These accelerated DM sources extend the experimental ability to scan the parameter space of light DM into the sub-GeV region. In this study, we specifically analyze DM accelerated by the Monogem Ring supernova remnant, whose age ($\sim 68000\mathrm{yr}$) and distance to Earth ($\sim 300$ parsec) are strategically matched to enable detection with current terrestrial detectors. Utilizing the $205.4\mathrm{kg}·\mathrm{day}$ data obtained from the CDEX-10 experiment at the China Jinping Underground Laboratory, we derive new constraints on boosted DM within the NREFT framework. The NREFT coupling constant exclusion regions now penetrate the sub-GeV mass range, with optimal sensitivity achieved for operators ${\mathcal{O}}_3$, ${\mathcal{O}}_6$, ${\mathcal{O}}_{15}$ in the 0.4–0.6 GeV mass range.

A mechanism for generating anisotropic enhancements of the curvature perturbation through a vector field is proposed. We find that when the mixing between the inflaton perturbation and the vector-field perturbation is sufficiently strong in the anisotropic inflation, the power spectrum becomes dominated by anisotropic constant modes. This suggests that statistical anisotropy in primordial black hole (PBH) formation may be inevitable if inflation undergoes an anisotropic inflationary phase. Our findings offer a novel approach to probe vector fields during inflation and to test the cosmic no-hair conjecture.

We report results from an updated search for neutral current (NC) resonant $\mathrm{\Delta }(1232)$ baryon production and subsequent $\mathrm{\Delta }$ radiative decay (NC $\mathrm{\Delta }\to N\gamma$). We consider events with and without final state protons; events with a proton can be compared with the kinematics of a $\mathrm{\Delta }(1232)$ baryon decay, while events without a visible proton represent a more generic phase space. In order to maximize sensitivity to each topology, we simultaneously make use of two different reconstruction paradigms, Pandora and Wire-Cell, which have complementary strengths, and select mostly orthogonal sets of events. Considering an overall scaling of the NC $\mathrm{\Delta }\to N\gamma$ rate as an explanation of the MiniBooNE anomaly, our data exclude this hypothesis at 94.4% CL. When we decouple the expected correlations between NC $\mathrm{\Delta }\to N\gamma$ events with and without final state protons, our data exclude an interpretation in which all excess events have associated protons at $2.0\sigma$, and are consistent with an interpretation in which all excess events have no associated protons at $0.63\sigma$.

We study certain higher-point thermal correlators of heavy and light scalar primaries in a holographic conformal field theory. Assuming simple self-interactions and couplings of the scalars in the bulk theory, we show that the thermal correlators contain a signature of the proper time to singularity from the horizon. The key idea is to use Wentzel-Kramers-Brillouin approximations for the propagators and evaluate the bulk integrals using saddle point method.

We present a generalized framework for $n$-photon processes involving a uniformly accelerated Unruh-DeWitt detector interacting with a massless scalar field. We utilize the $n$th-order Dyson series to derive the final quantum state for an arbitrary number of interactions. Our analysis covers both even-order processes, which return the detector to its initial state, and odd-order processes, which result in a change of the detector’s state. By employing a unified formalism and performing a complete, time-ordered integration, we obtain exact analytical expressions for the $n$-photon states. The results reveal a rich structure of resonant denominators corresponding to multiparticle processes, including new field-mediated resonances independent of the detector’s energy gap for $n>2$. Crucially, the analysis of odd-order transitions reveals an exponential factor, $\exp (-\pi \omega /a)$, characteristic of the Unruh thermal bath. By considering processes starting from the detector’s excited state, we demonstrate that the ratio of excitation to deexcitation amplitudes precisely recovers the Boltzmann factor, providing a higher-order confirmation of thermal detailed balance for the Unruh effect. This work provides a unified tool for studying multipartite entanglement and thermal phenomena in noninertial frames.

Robustly measuring binary black hole spins via gravitational waves is key to understanding these systems’ astrophysical origins, but remains challenging—especially for high-mass systems, whose signals are short and dominated by the merger. Nonetheless, events like GW190521 show that strong spin precession can indeed be gleaned from high-mass systems. In this work, we track how spin precession imprints on simulated high-mass binary black hole signals cycle-by-cycle using time-domain inference. We investigate a suite of signals, all with the same spins and (near-unity) mass ratio—yielding identical spin evolution—but different signal-to-noise ratios, total masses, and extrinsic angles, all of which affect the observed waveform morphology. We truncate each signal at various times and infer source parameters using only the data before or after each cutoff. The resultant posterior allows us to identify which time segments of each signal inform its spin precession constraints. We find that at a sufficiently high post-peak signal-to-noise ratio (SNR, $\rho \sim 20$), spin precession can be constrained by the nrsur7dq4 waveform model when just the post-peak data (i.e., ringdown) are visible. Similarly, at a large enough pre-cutoff SNR ($\rho \sim 10$), spin precession can be constrained using only pre-peak data (i.e., inspiral)—this occurs for signals with detector-frame total mass $\lesssim 100M_{\odot }$ at GW190521’s full-signal SNR. Finally, we vary the inclination, polarization, and phase angles, finding that their configuration need not be fine-tuned to measure spin precession, even for very high-mass and short signals with two to three observable cycles. We do not find that the same morphological features consistently drive precession constraints: in some signals, precession inference hinges on the relationship between a loud merger and quiet pre-merger cycle, as was the case for GW190521, but this is not generically true. Our studies enable a morphological understanding of precession that can help bolster confidence in precession inference in the presence of signal or noise systematics.

Binary black holes (BBHs) in eccentric orbits produce distinct modulations in the emitted gravitational waves (GWs). The measurement of orbital eccentricity can provide robust evidence for dynamical binary formation channels. We analyze 57 GW events from the first, second, and third observing runs of the Laser Interferometer Gravitational-Wave Observatory (LIGO)-Virgo-Kamioka Gravitational Wave Detector (KAGRA) (LVK) Collaboration using a multipolar aligned-spin inspiral-merger-ringdown waveform model with two eccentric parameters: eccentricity and relativistic anomaly (assuming a quasicircular merger-ringdown). This is made computationally feasible with the machine-learning code dingo, which accelerates inference by 2–3 orders of magnitude compared to traditional inference techniques. First, when using a uniform prior on the eccentricity, we find eccentric aligned-spin against quasicircular aligned-spin ${\log }_{10}$ Bayes factors of 1.84 to 4.75 (depending on the glitch mitigation) for GW200129, 3.0 for GW190701 and 1.77 for GW200208_22. We infer $e_{\mathrm{gw},10\mathrm{Hz}}$ $(e_{\mathrm{gw},20\mathrm{Hz}})$ to be ${0.27}_{-0.12}^{+0.10}$ (${0.16}_{-0.05}^{+0.04}$) to ${0.17}_{-0.13}^{+0.14}$ (${0.1}_{-0.04}^{+0.05}$) for GW200129, ${0.54}_{-0.30}^{+0.12}$ (${0.31}_{-0.13}^{+0.12}$) for GW190701 and ${0.39}_{-0.23}^{+0.23}$ (${0.21}_{-0.08}^{+0.08}$) for GW200208_22. Second, we find ${\log }_{10}$ Bayes factors between the eccentric aligned-spin versus quasicircular precessing-spin hypothesis between 1.43 and 4.92 for GW200129, 2.61 for GW190701 and 1.23 for GW200208_22. Third, our analysis does not show evidence for eccentricity in GW190521, which has an eccentric aligned-spin against quasicircular aligned-spin ${\log }_{10}$ Bayes factor of 0.04. Fourth, we estimate that if we neglect the spin-precession and use an astrophysically motivated prior on the rate of eccentric BBHs, the probability of one out of the 57 events being eccentric is greater than 99.5% or $(100-8.4\times {10}^{-4})\%$ (depending on the glitch mitigation). Fifth, we study the impact on parameter estimation when neglecting either eccentricity in quasicircular models or higher modes in eccentric models for GW events. These results underscore the importance of including eccentric parameters in the characterization of BBHs for the upcoming observing runs of the LVK Collaboration and for future detectors on the ground and in space, which will probe a more diverse BBH population.

We investigate light propagation in self-gravitating systems composed of an axially symmetric, stationary, rotating dust fluid. These configurations are intrinsically relativistic, sustained entirely by their rotation, since no compact or finite dust distribution can exist under the same symmetry conditions in Newtonian gravity. In such systems, rotational effects arise from off-diagonal components of the spacetime metric, which are not negligible compared to their Newtonian counterparts. We analyze how these components affect the deflection angle of light, showing that they can be interpreted as contributing an additional effective mass. Moreover, their presence can, in principle, be detected through the characteristic asymmetry they induce in the images of background sources.

The (degenerate) geometry of event horizons is linked to Carrollian fluids. We investigate the behavior of event horizons via a perturbative coupling to a massless scalar field, making connections to Carrollian hydrodynamics with a driving source, and discuss the fluid equilibration in tandem with the horizon’s relaxation to equilibrium. We observe that after the perturbation dies off, the Carrollian fluid energy and momentum densities approach equilibrium as the horizon asymptotically becomes nonexpanding. We connect the equilibration of the Carrollian fluid dual to the black hole horizon through the expansion of its background geometry.

We investigate limitations of causality arguments from flat-spacetime amplitudes, based on the eikonal limit of gravitational scattering, to place constraints on modified gravity. We show that causality constraints are only valid in the weak-gravity regime even for trans-Planckian scattering, and that such constraints are much less stringent than astrophysical ones, obtained for example from gravitational waves emitted in black hole coalescence. Special attention is given to the weakness of causality constraints on dynamical Chern-Simons gravity, but our results apply to other modified gravity theories as well. In the context of that theory, we also discuss how to obtain a time-delay formula from black holes, neutron stars, and shock wave solutions. For scattering with compact objects, we explicitly show that time delays are greatly suppressed by the ratio of the object’s mass to the impact parameter, so time advances only occur greatly outside the cut off of the theory. For the shock wave solution, we find that the time delay is always positive within the regime of validity of the solution. We also comment on the impact of graviton nonlinearities for time-delay calculations in the nonlinear, strong gravity regime. We conclude that amplitude-based causality constraints on modified gravity are typically not stringent relative to other experimental and observational bounds.

The diffeomorphism covariance is a fundamental property of general relativity that leads to the fact that the same solution of the Einstein equation can be given in completely distinct forms in different coordinate systems. Distinguishing or identifying two metrics as solutions of the Einstein equation is particularly challenging. In a recent paper [Lu and Mao, Four-dimensional stationary algebraically special solutions and soft hairs, arXiv:2503.14586.], it was proposed to apply the relations of different Weyl invariants to distinguish solutions. In this paper, we present a complementary application of the Weyl invariants. We verify from Weyl invariants that two metrics with completely different forms are the same solution. We also present the coordinates transformation that connects the two metrics.

Noise maps from cosmic microwave background (CMB) experiments are generally statistically anisotropic, due to scanning strategies, atmospheric conditions, or instrumental effects. Any mismodeling of this complex noise can bias the reconstruction of the lensing potential and the measurement of the lensing power spectrum from the observed CMB maps. We introduce a new CMB lensing estimator based on the maximum a posteriori (MAP) reconstruction that is minimally sensitive to these instrumental noise biases. By modifying the likelihood to rely exclusively on correlations between CMB map splits with independent noise realizations, we minimize autocorrelations that contribute to biases. In the regime of many independent splits, this maximum closely approximates the optimal MAP reconstruction of the lensing potential. In simulations, we demonstrate that this method is able to determine lensing observables that are immune to any noise mismodeling with a negligible cost in signal-to-noise ratio. Our estimator enables unbiased and nearly optimal lensing reconstruction for next-generation CMB surveys.

We present an explicit formulation of cosmological perturbation theory for three-field models with a flat field space. By performing rotations to align one field with the direction of curvature perturbations and applying the same rotations to the other two field directions, we introduce the semikinematic basis, which is applicable to models with more than two fields. We derive the governing equations in this basis. We also stress a characteristic property of more-than-two-field models: the freedom in choosing the isocurvature perturbations. This framework enables the computation of the curvature and two isocurvature power spectra for any given potential. We numerically solve the background and perturbation equations for three distinct scenarios. First, to validate the consistency of our three-field formalism, we examine an effective two-field model inspired by the two-block case of the multigiant vacua matrix inflation scenario. Next, we analyze a purely three-field system without direct interfield interactions. Finally, we study a three-field case that incorporates direct interactions. For all scenarios, we numerically compute the curvature perturbation power spectra and highlight the effects of rapid turns on the spectra. Finally, we investigate the relationship between these quantities and the observables in the early radiation-dominated era. Through both general arguments and a simple example, we show that three-field inflation can yield a much richer phenomenology. This is particularly true when we assume the initial perturbations in the radiation era include two isocurvature modes.