We investigate the electromagnetic form factors of the nucleon within an effective chiral theory derived from the QCD instanton vacuum, taking into account the finite current quark mass. The momentum-dependent dynamical quark mass, generated by the instanton-antiinstanton medium, naturally plays the role of a regulator, so that no additional regularization is required to tame the divergences arising from quark loops. The instanton parameters, the average instanton size $\overline{\rho }=0.35\mathrm{fm}$, and the average interdistance $\overline{R}=0.86\mathrm{fm}$, together with the dynamical quark mass at zero virtuality $M_0=385\mathrm{MeV}$, are all fixed by the saddle-point equation beyond the chiral limit, leaving no adjustable free parameter in the present calculation. We compute the Sachs electric and magnetic form factors of the proton and neutron, the nucleon charge and magnetization radii, the magnetic moments, and the ratios ${\mu }_{p,n}{G}_E^{p,n}(Q^2)/G_M^{p,n}(Q^2)$. The present results are compared with the experimental data, the chiral quark-soliton model ($\chi \mathrm{QSM}$), and the Kelly parametrization. The proton charge radius, $\sqrt{⟨r^2{⟩}_{\mathrm{ch}}^p}=0.841\mathrm{fm}$, is in remarkable agreement with the recent muonic-hydrogen value, and the $Q^2$ dependence of the proton form-factor ratio ${\mu }_p{G}_E^p/G_M^p$ is reproduced very well, in clear contrast to the $\chi \mathrm{QSM}$. The overall agreement with the experimental data confirms that the effective chiral theory derived from the QCD instanton vacuum provides a consistent and predictive framework for describing the electromagnetic structure of the nucleon.

The decay ${\eta }_c\to p\overline{p}\eta$ is observed for the first time with a significance of exceeding $10\sigma$. It is found by analyzing $(2712.4\pm 14.3)\times {10}^6\psi (3686)$ events accumulated at the BESIII detector. The measured branching fraction of ${\eta }_c\to p\overline{p}\eta$ via $\psi (3686)\to \gamma p\overline{p}\eta$ is significantly influenced by the interference between the resonant ${\eta }_c$ decay and the nonresonant process $\psi (3686)\to \gamma p\overline{p}\eta$ and is measured in both constructive- and destructive-interference scenarios. The joint branching fraction of $\psi (3686)\to \gamma {\eta }_c$, ${\eta }_c\to p\overline{p}\eta$ is measured to be $(3.2\pm 0.1\pm 0.8)\times {10}^{-6}$ or $(8.7\pm 0.3\pm 1.7)\times {10}^{-6}$ for constructive- or destructive-interference solutions, respectively, where the first uncertainties are statistical and the second systematic. The branching fraction of ${\eta }_c\to p\overline{p}\eta$ is determined to be $\mathcal{B}({\eta }_c\to p\overline{p}\eta )=(0.90\pm 0.04\pm 0.21\pm 0.13)\times {10}^{-3}$ or $(2.42\pm 0.07\pm 0.48\pm 0.34)\times {10}^{-3}$ for the two solutions, respectively, where the third uncertainties are due to the uncertainty in the branching fraction of $\psi (3686)\to \gamma {\eta }_c$.

Precision measurements of four neutrino oscillation parameters, ${\theta }_{12}$, ${\theta }_{13}$, $\mathrm{\Delta }{m}_{21}^2$, and |$\mathrm{\Delta }{m}_{31}^2$|, face significant interference from a previously overlooked correlated background. Recent findings from the SNO+ and JUNO experiments reveal that cascade decays of ${}^{214}\mathrm{Bi}\text{−}{}^{214}\mathrm{Po}$ in liquid scintillator detectors can mimic inverse beta decay signals from reactor and geoneutrinos, with a misidentification probability on the order of ${10}^{-4}$ when hydrogen neutron capture is used, a rate ten times higher than geant4 simulations predicted. This work identifies the ${}^5\mathrm{Li}$ resonance in $\alpha \text{−}p$ elastic scattering as the underlying cause. For alpha energies above 5 MeV, the cross section is hundreds of times larger than that of Rutherford scattering. After correctly incorporating the differential cross section into geant4, the misidentification probability is recalculated as $1.9\times {10}^{-4}$. The simulated shape of the long tail in the alpha deposited energy also differs from the extrapolation models currently used by SNO+ and JUNO. These results will assist both experiments in more accurately estimating this novel background, thereby refining measurements of neutrino oscillation parameters and the geoneutrino flux. Additionally, the study implies an overlooked background with a rate of 0.5 events per detector per day in the Daya Bay ${\theta }_{13}$ analysis using hydrogen neutron capture, leading to an increase of ${\sin }^{2}2{\theta }_{13}$ by approximately 0.010. Consequently, the Particle Data Group’s reported ${\sin }^2{\theta }_{13}$ value shall increase by about 0.006 ($1\sigma$).

A new technique is developed to identify dielectrons ($e^{+}{e}^{-}$) with Lorentz boost ${\gamma }_{\mathrm{L}}>20$ that produce one single merged cluster in the electromagnetic calorimeter of the CMS detector. The identification uses two multivariate models: one for the case where both electron tracks are reconstructed, and another where only one of the tracks is reconstructed. The efficiency is determined using proton-proton collision data collected at a center-of-mass energy of 13 TeV. Boosted $J/\psi$ mesons decaying into $e^{+}{e}^{-}$ pairs are used to estimate the efficiency of the model with two tracks, yielding an overall efficiency of 80%. The $Z\to {\mu }^{+}{\mu }^{-}\gamma$ events, where the photon converts into a collimated dielectron, are used for the model with a single track, yielding an efficiency of about 60%. A dedicated energy correction for dielectron candidates is also developed using $B^{\pm }\to J/\psi K^{\pm }\to e^{+}{e}^{-}{K}^{\pm }$ data.

In this paper, we revisit the smoothness of the classical limit of inclusive observables in the formalism developed by Kosower, Maybee and O’Connell (KMOC). Building on the earlier work, we prove that the classical limit of three classes of inclusive observables, namely scattering angle, radiative field, and angular impulse is smooth and does not suffer from any so-called superclassical divergences at all orders in perturbation. We use scalar QED as a model. Our analysis goes some way in showing that KMOC formalism can be used to compute classical radiation by simply focusing on all the terms that scale as ${\hslash }^0$, as all the terms that scale with inverse power of $\hslash$ vanish. Through this analysis, we have successfully isolated the classes of terms that contribute to the classical limit, thereby allowing direct and more efficient computations of physical observables.

In this paper, we show how the dynamical tidal response of a neutron star can be systematically defined within the worldline effective field theory (EFT) framework, and relate it to the gauge-invariant amplitude for gravitational-wave scattering off an isolated star. We compute this amplitude both within the EFT, using standard quantum field-theory techniques, and within stellar perturbation theory (the corresponding ultraviolet theory), solving the coupled metric and matter perturbation equations numerically in the stellar interior and matching to the analytical Mano-Suzuki-Takasugi solutions in the vacuum exterior. Matching the amplitude between the two theories fixes the dynamical tidal response. The result is consistent with known expectations, including the static limit and the behavior near the star’s resonant modes, and it recovers the imaginary part of the dominant oscillation mode induced by gravitational-wave dissipation. We conclude with a discussion of potential improvements within both the EFT and the perturbation theory.

The Hubble tension is commonly framed as a discrepancy between local, late-time measurements favoring $H_0\approx 73\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ and early-time, sound-horizon-based measurements favoring $H_0\approx 67\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$. We challenge this viewpoint by analyzing 88 sound-horizon-free $H_0$ measurements, categorized into four classes: distance ladder measurements using local calibrators; local $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) measurements assuming the standard expansion history; pure local measurements independent of $H(z)$ shape; and cosmic microwave background (CMB) sound-horizon-free measurements using CMB data without the sound horizon scale. Our analysis reveals that the 30 distance ladder measurements yield $H_0=72.73\pm 0.39\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ (${\chi }_{\nu }^2=0.72$), while the 58 distance ladder-independent/sound horizon free measurements collectively yield $H_0=69.37\pm 0.34\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ (${\chi }_{\nu }^2=0.95$). After accounting for realistic correlations between measurements, the tension between the two ensembles is $3.9-4.3\sigma$ depending on the assumed correlation strength; we adopt the conservative value of $3.9\sigma$ as our reference estimate. Under the idealized assumption of fully independent measurements it would reach $6.5\sigma$. Among categories, Local $\mathrm{\Lambda }\mathrm{CDM}$ measurements favor the lowest value ($H_0=67.61\pm 0.96\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$), pure local yields an intermediate value ($H_0=71.03\pm 0.69\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$), and CMB sound horizon free measurements give $H_0=69.07\pm 0.44\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$. Within the sound-horizon-free sample considered here, the distance ladder thus sits systematically high compared with all other methodologies, a result that is stable under all tested variations of the measurement categorization. This suggests that the Hubble tension may be more accurately characterized as a discrepancy between the distance ladder and all other methodologies, rather than as a purely early- vs late-time split. We also identify an internal tension among distance ladder-independent/sound horizon free measurements, which is however sensitive to categorization choices, ranging from $1.5\sigma$ to $3.1\sigma$ ($2.9\sigma$ in our baseline analysis): analyses assuming $\mathrm{\Lambda }\mathrm{CDM}$ systematically recover lower $H_0$ values by $\sim 3.4\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ compared to cosmological-model-independent methods. This suggests either unrecognized systematics in the distance ladder or deviations from $\mathrm{\Lambda }\mathrm{CDM}$ or both.

We present the methodology for the weak lensing and galaxy clustering analyses of the Dark Energy Survey (DES) Year 6 dataset. In this work, we design and validate the analysis pipeline for the cosmic shear, galaxy clustering plus galaxy–galaxy lensing ($2\times 2\mathrm{pt}$), and the joint analysis in the $3\times 2\mathrm{pt}$. Our framework accounts for key theoretical uncertainties, such as baryonic feedback and galaxy bias, incorporating both linear and nonlinear models. We apply scale cuts in regimes where theoretical modeling becomes unreliable. The robustness of the pipeline is validated using mock data and simulations, confirming unbiased cosmological constraints and highlighting the importance of posterior projection effects in the validation process. As a result, we deliver robust and validated analysis pipelines for cosmic shear, $2\times 2\mathrm{pt}$, and $3\times 2\mathrm{pt}$ in $\mathrm{\Lambda }\mathrm{CDM}$ and $w\mathrm{CDM}$ scenarios, including a well-defined set of scales suitable for real data analysis, a robust prescription for theoretical systematics, and the theoretical covariance of the signal. This comprehensive methodology also lays the groundwork for future galaxy surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time.

We present a quotient-space Bayesian formulation for DESI-Era anomaly interpretation. Given a pattern-labeled catalog with map $i\mapsto \mathbf{A}(i)$, the induced posterior $p(\mathbf{A}|D)$, sector inclusion probabilities $P_{\alpha }$, coactivation probabilities $P_{\alpha \beta }$, and grouped Bayes factors $B_{\alpha }(D)$ are exact summaries over predeclared physical activation events. Pairwise comparisons such as $\mathrm{\Lambda }\mathrm{CDM}$ versus $w_0{w}_a\mathrm{CDM}$ remain ordinary Bayes-factor tests between specified families; the quotient construction addresses the coarser question of which physical sector carries posterior support when different sectors are represented by unequal numbers of catalog elements. We derive a sector-resolved DESI-CMB-SN likelihood specification for late-time background, early-time ruler, supernova calibration, perturbation, and gravitational-wave propagation sectors. The construction includes an Alcock-Paczynski/isotropic-scale BAO decomposition, a pure-ruler projection, analytic marginalization of low-rank supernova calibration modes, Fisher-normalized sector priors, inactive-sector leakage tests, log-evidence uncertainty propagation, and prior/sector-partition diagnostics. The result is a quantitative procedure for reporting model-comparison support at the level of physically interpretable sectors.

The modulation of Galactic cosmic rays, driven by the evolution of the heliospheric magnetic field, strongly influences the intensity of cosmic rays reaching near-Earth space. Characterizing this process is crucial both for advancing our understanding of cosmic-ray transport and for assessing radiation exposure and related hazards in space environments. Here we present a newly developed forecasting framework built on a numerical description of charged particle transport in the heliosphere and its dependence on solar activity, designed for the long-term forecasting of Galactic cosmic-ray fluxes. It solves a one-dimensional, spherically symmetric form of the Parker transport equation, including diffusion, solar-wind advection, and adiabatic energy losses. The model has been validated using multispecies flux measurements from space-based experiments: PAMELA, AMS-02, and ACE. Its strategy is based on Hilbert-Huang transform filtering and cross-correlation between delayed solar proxies and effective model parameters. Our charge-sign- and rigidity-dependent parametric description of the diffusion-advection processes yields good overall agreement with the data, as shown by the reconstruction uncertainty. The robustness of this approach is validated across a broad set of multichannel datasets covering different particle species, energy ranges, and phases of solar activity, supporting its applicability to space radiation monitoring and forecasting. Furthermore, when coupled with solar-proxy forecasting models, it enables decadal-scale predictions of Galactic cosmic-ray fluxes, thereby supporting long-term planning and radiation-risk assessment for future space missions.

Solar-reflected dark matter consists of dark-matter particles up-scattered and accelerated by energetic electrons in the solar interior, producing a high-velocity tail that can enhance signals in direct-detection experiments, especially for MeV-scale masses. We consider an inelastic dark matter (iDM) model, in which solar scattering populates the excited state; subsequent deexcitation in terrestrial detectors releases the mass-splitting energy, substantially helping the energy release of the collision to be larger than the detector threshold. Using detailed Monte Carlo simulations, we generate the velocity and energy distributions of solar-reflected iDM over a range of dark-matter masses $m_{\chi }$ and mass splittings $\mathrm{\Delta }$. We then compute event rates and energy depositions for current xenon and semiconductor experiments. Our results show that these experiments can place new constraints on the parameter space of MeV-scale iDM.

The LIGO-Virgo-KAGRA consortium has sporadically detected inspiral-dominated gravitational-wave events such as GW170817 and GW190425. These events offer an opportunity to constrain possible initial (residual) orbital eccentricities using purely inspiral template families. We detail the implementation of an lalsuite approximant, TaylorF2Ecck, which analytically models inspiral gravitational waves from nonspinning compact binaries in post-Newtonian (PN)-accurate eccentric orbits and restricts the initial-eccentricity contributions to leading order. Specifically, our frequency-domain approximant consistently incorporates orbital, advance of periastron, and gravitational-wave emission effects fully up to 3PN order. We conduct detailed parameter-estimation studies of GW170817 and GW190425 using TaylorF2Ecck, following comprehensive sanity checks to validate model performance and investigate the influence of eccentricity and periastron advance in the relevant parameter space. The results indicate that the initial eccentricity at 20 Hz is negligible within the 90% credible intervals (less than 0.016 for GW170817 and less than 0.023 for GW190425, with both posterior distributions railing toward zero), and Bayes factors show no strong evidence favoring the eccentric waveform over the quasicircular waveform. At such negligible initial eccentricities, comparisons between eccentric models with and without periastron advance show no clear signature of this effect, with no significant model-dependent shifts in the posterior distributions and no strong Bayes-factor evidence favoring one model over the other. Additionally, these detailed studies reveal the importance of incorporating initial-eccentricity contributions at least up to 3.5PN order and discuss its implications. We substantiate this inference by employing versions of the quasicircular TaylorF2 approximant that incorporate Fourier phase contributions beyond the conventional 3.5PN order.

Modeling extreme-mass-ratio inspirals hinges on the accurate and efficient computation of gravitational-wave fluxes from generic Kerr orbits. Conventional frequency-domain techniques are often limited by costly auxiliary parameter searches and numerical instabilities in the strong-field or high-frequency regimes. We address these challenges by reformulating both the angular and radial Teukolsky equations in terms of confluent Heun functions. Employing a hybrid analytic continuation algorithm to compute the connection coefficients eliminates the dependence on auxiliary parameters, directly yielding globally convergent solutions and scattering amplitudes. To resolve the highly oscillatory source integrands for generic orbits, we implement an adaptive bipower mapping quadrature. Comprehensive benchmarks under standard double-precision arithmetic demonstrate that, for the total radiative flux summed over 168 low-order modes, our method achieves relative errors of order ${10}^{-11}$, with computational costs typically reduced by factors of 3–13 compared to the state-of-the-art generalizedsasakinakamura.jl and pybhpt packages. Notably, for highly oscillatory high-order modes, our framework achieves a speedup of up to 60 times compared to specialized oscillatory integrators like generalizedsasakinakamura.jl. These demonstrated gains in precision and efficiency establish the framework as a robust tool for strong-field perturbation theory, providing the numerical foundation for high-order, self-force calculations and rapid, high-precision waveform generation.

Motivated by the recent anomalies related to $b\to (c,u)l{\overline{\nu }}_l$ decays, we perform a theoretical investigation to search for new physics in ${\mathrm{\Lambda }}_b$ decays through $W^{\prime }$ and scalar LQ model. We have studied ${\mathrm{\Lambda }}_b\to ({\mathrm{\Lambda }}_c,p)\tau {\overline{\nu }}_{\tau }$ decays, which involve a $b\to (c,u)\tau {\overline{\nu }}_{\tau }$ quark level transition. To fix the values of the new coupling parameters, we performed ${\chi }^2$ fitting using experimental results of $R_{D^{*}}$, $R_{J/\psi }$, $R_{\pi }^l$, $Br(B_c^{+}\to {\tau }^{+}{\nu }_{\tau })$, $Br(B^{-}\to {\tau }^{-}{\overline{\nu }}_{\tau })$, and $Br(B^0\to {\pi }^{+}{\tau }^{-}\overline{\nu })$. Incorporating the best fit values of new coupling parameters, we have calculated values of the branching ratios, the lepton flavor nonuniversalities ratios, the lepton longitudinal polarization asymmetry, the lepton hadron polarization asymmetry, the forward backward asymmetry, and the ratio of the partially integrated decay rate of ${\mathrm{\Lambda }}_b\to p\tau {\overline{\nu }}_{\tau }$ over the ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c\tau {\overline{\nu }}_{\tau }$. Except for forward-backward asymmetry and leptonic hadron polarization asymmetry, some observables show significant deviations, while others show slight inconsistencies with their standard model predicted values.

We report on the first search for nuclear ultraheavy dark matter (UHDM) in a dual-phase liquid argon time projection chamber using the DarkSide-50 experiment. Unlike conventional weakly interacting massive particles, a nuclear UHDM model may be composed of many dark nucleons and scatter numerous times while passing through the detector. Accounting for energy loss through the Earth’s overburden, we apply selection criteria optimized for multiscatter event topologies using the 532-day low-radiation campaign of the DarkSide-50 detector. Excluded limits on the UHDM-nucleon scattering cross section for dark nucleon masses of $m_{\chi }=10,50,100,500\mathrm{GeV}/{\mathrm{c}}^2$ are presented.

The standard model of cosmology, $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$), is plagued by various tensions with recent observations. The most pressing one is the Hubble tension, where the observed expansion rate of our Universe is $5\sigma$ larger than that predicted by $\mathrm{\Lambda }\mathrm{CDM}$. Recently, the result from DESI also reveals a new inconsistency between the baryon acoustic oscillation and cosmic microwave background (CMB) observations in $\mathrm{\Lambda }\mathrm{CDM}$. It is found that these major cosmological tensions can be traced back to a common physical origin—the nonminimal coupling between gravity and matter, different from the expectation of general relativity (GR). Bayesian model comparison reveals strong evidence of nonminimally coupled gravity over GR and $\mathrm{\Lambda }\mathrm{CDM}$, with a Bayes factor $\ln B=+12.1$. The nonminimal coupling model predicts that gravity in the early Universe should be $\sim 5\%$ stronger on cosmological scales than it is today, which is consistent with current observation and will be tested by upcoming CMB and big bang nucleosynthesis experiments.

We develop a semiclassical framework to determine scaling dimensions of neutral composite operators in scalar conformal field theories. For the critical Ising $\lambda {\varphi }^4$ theory in $d=4-\epsilon$, we obtain the full spectrum of composite operators built out of $n$ fields transforming according to the various Lorentz representations to next-to-leading order in the double-scaling limit $n\to \infty$ and $\lambda \to 0$ with $\lambda n$ fixed. At any given order, the semiclassical expansion resums an infinite number of Feynman diagrams. Combining our results with existing perturbative computations further yields the complete five-loop scaling dimensions in the $\epsilon$-expansion for the family of ${\varphi }^n$ operators. Finally, extrapolating the semiclassical results to three dimensions leads to a competitive alternative to existing methodologies.

We formulate Carroll hydrodynamics with the inclusion of a spin current. Our strategy relies on the fact that the $c\to 0$ limit of relativistic hydrodynamics yields the equations of Carroll hydrodynamics. Starting with the preultralocal parametrization of the background geometry and the hydrodynamic degrees of freedom for a relativistic fluid endowed with a spin current, the $c\to 0$ limit produces Carroll hydrodynamics with spin. It is known that boost-invariant hydrodynamic models for ultrarelativistic fluids relevant for the physics of quark-gluon plasma, such as Bjorken and Gubser flow, are manifestations of Carroll hydrodynamics under appropriate geometric choices for the underlying Carrollian structure. In this work, we further this mapping between such boost-invariant models and Carroll hydrodynamics, now with the inclusion of a spin current.

This paper investigates the structure and properties of neutron stars in four-dimensional nonpolynomial gravities. Solving the modified Tolman-Oppenheimer-Volkoff equations for three different equations of state (BSk19, SLy4, AP4), we confirm that neutron star solutions remain in existence. As the modification parameter $\alpha$ increases, neutron stars grow in both radius and mass. We find that, when the parameter $\alpha$ is sufficiently large, a frozen state emerges at the end of the neutron-star sequence. In this state, the metric functions approach zero extremely close to the stellar surface, forming a critical horizon, making it nearly indistinguishable from a black hole to an external observer. Such a frozen neutron star constitutes a universal endpoint of the neutron-star sequence in this theory, independent of the choice of the equation of state. Based on our results and current observational constraints, we derive bounds on the modification parameter $\alpha$ and show that frozen neutron stars remain allowed in the bounds.