We report a study of the semileptonic decays $D^0\to {\overline{K}}^0{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ (where $\ell =e$, $\mu$) based on a sample of $20.3{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. Based on an investigation of the decay dynamics in $D^0\to {\overline{K}}^0{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decays, a $\mathcal{D}$-wave component of $D^0\to K_2^{*}(1430{)}^{-}{\ell }^{+}{\nu }_{\ell }$ is observed for the first time with a statistical significance of $8.0\sigma$, in addition to the dominant $K^{*}(892{)}^{-}$ and $\mathcal{S}$-wave components. The $\mathcal{D}$-wave component is determined to account for $(0.092\pm 0.028_{\mathrm{stat}}\pm 0.018_{\mathrm{syst}})\%$ of the total decay rate. The branching fractions of the dominant $K^{*}(892{)}^{-}$ components are measured as $\mathcal{B}(D^0\to K^{*}(892{)}^{-}{e}^{+}{\nu }_e)=(2.043\pm 0.018_{\mathrm{stat}}\pm 0.012_{\mathrm{syst}})\%$ and $\mathcal{B}(D^0\to K^{*}(892{)}^{-}{\mu }^{+}{\nu }_{\mu })=(1.964\pm 0.018_{\mathrm{stat}}\pm 0.012_{\mathrm{syst}})\%$, which are the most precise measurements to date and represent significant improvements over the previous world averages. The hadronic form-factor parameters are measured to be $r_V=V(0)/A_1(0)=1.444\pm 0.026_{\mathrm{stat}}\pm 0.010_{\mathrm{syst}}$, $r_2=A_2(0)/A_1(0)=0.752\pm 0.020_{\mathrm{stat}}\pm 0.004_{\mathrm{syst}}$, and $A_1(0)=0.618\pm 0.002_{\mathrm{stat}}\pm 0.004_{\mathrm{syst}}$, where $V(0)$ is the vector form factor and $A_{1,2}(0)$ are the axial-vector form factors evaluated at $q^2=0$. This is the most precise determination of the form-factor parameters to date measured in a $D\to K^{*}(892)$ transition. In addition, we report the first model-independent measurement of the $\mathcal{S}$-wave phase shift in the hadronic ${\overline{K}}^0{\pi }^{-}$ system. We also measure the relative ratio between branching fractions of $D^0\to K^{*}(892{)}^{-}{\mu }^{+}{\nu }_{\mu }$ and $D^0\to K^{*}(892{)}^{-}{\mu }^{+}{\nu }_{\mu }$ to be ${\mathcal{R}}_{K^{*}(892)}^{\mu /e}=0.961\pm 0.012_{\mathrm{stat}}\pm 0.005_{\mathrm{syst}}$, and no violation of lepton flavor universality is found.

We study a proposed holographic representation of spread/Krylov complexity for states or operators dual to charged, composite, and extended probes. Our analysis builds on the relation between the rate of spread complexity and the proper momentum of an infalling bulk excitation. A conserved Noether charge requires particular care: unitary spread complexity satisfies ${\dot{\mathcal{C}}}_K(0)=0$, and therefore the velocity conjugate to a fixed charge cannot be counted as an independent spreading direction. We consequently eliminate cyclic coordinates by a partial Legendre transform and compute the proper momentum from the fixed-charge Routhian. We first apply this prescription to an $R$-charged particle in ${\mathrm{AdS}}_5\times S^5$. The charge enters through the reduced effective mass and energy, while the resulting complexity has the required quadratic onset. We next study probes that are pointlike from the boundary perspective but possess nontrivial bulk structure. These are baryon-vertex configurations and giant gravitons. For the giant graviton the fixed-charge prescription retains the effects of the Born-Infeld and Wess-Zumino couplings without reintroducing the cyclic angular velocity into the proper momentum. We also analyze a fundamental string falling in anti–de Sitter (AdS) while stretched along a boundary spatial direction as a collective model of a nonlocal excitation. Within the rigid-probe Poincaré-AdS examples considered here, the proper-momentum rate is linear at late times, whereas charges, compositeness, and spatial extension affect its normalization and its subleading or intermediate-time structure. We interpret this as a robust pattern in the tested class (not as a general universality theorem). The fixed-charge Routhian provides a candidate bulk counterpart of sector selection. An explicit symmetry-resolved boundary Lanczos construction remains an open problem.

We consider the relative entropy between the vacuum and a coherent state in the Rindler wedge for an interacting $\lambda {\varphi }^4$ theory to first order in $\lambda$. We construct the perturbatively interacting Weyl algebra of the wedge, and employ Tomita-Takesaki modular theory and the Araki-Uhlmann formula to compute the relative entropy. We verify that the relative entropy reduces to the classical (interacting) boost Noether charge, analogously to the free theory, and that the Bekenstein bound holds.

The backwards one-body (BOB) model provides a fully analytical and physically motivated description of the merger-ringdown gravitational radiation emanating from a black-hole binary merger. We perform a comprehensive validation of BOB for the dominant (2,2) mode of quasicircular and nonprecessing systems, assessing its accuracy against numerical relativity (NR) simulations, state-of-the-art waveform models, and a sum of quasinormal modes. We demonstrate that BOB most accurately describes the gravitational wave news, achieving accuracy comparable to highly calibrated effective-one-body and NR surrogate models. Because BOB is minimally tuned to NR catalogs, it retains a high level of accuracy in regions of the parameter space sparsely covered by current NR catalogs. BOB yields an analytic link between the amplitude of the fundamental quasinormal mode and the peak amplitude of the news, which we verify to within the errors of a surrogate ringdown model. We identify a flavor of BOB that requires only the remnant mass and spin, yet matches the accuracy of models that fit a sum of many overtones. Last, we show that BOB accurately models both the mass and current quadrupole waves for superkick configurations, contrary to a claim in the literature, and explain why that study was not actually implementing BOB as it has been defined. Our findings establish BOB as a powerful tool for gravitational wave analysis, for providing independent tests of NR-calibrated models, and for better understanding the underlying physics of the merger. We provide a companion python package, gwBOB, allowing for the easy construction of various flavors of BOB and comparison to NR waveforms.

We study the dynamical and scattering properties for the Euler-Heisenberg black holes surrounded by perfect fluid dark matter. The geometry contains a compact nonlinear electrodynamic correction governed by the Euler-Heisenberg coupling and a logarithmic dark-matter contribution governed by the surrounding perfect fluid dark matter (PFDM) halo. We study the scalar, electromagnetic, and a particular effective axial spin-2 channel constructed on the fixed Euler-Heisenberg plus PFDM background, acting as a proxy for the gravitational-like perturbation problem and not for the fully coupled gravitational perturbation problem. We compute the quasinormal-mode spectrum employing a 13th-order Wentzel-Kramers-Brillouin method supplemented with Padé resummation and compare it with the eikonal prediction calculated in terms of the angular frequency of the photon sphere and the Lyapunov exponent. Moreover, we study the near-extremal configurations and derive a purely imaginary branch of quasinormal frequencies in the near-horizon region, whose damping rate increases with the PFDM parameter and is nearly spin independent. We then compute exact graybody factors by direct numerical integration of the radial wave equation and compare them to analytical lower bounds. We also analyze the absorption cross sections and the Hawking emission spectra. We also calculate the relativistic enhancement of the neutrino-antineutrino annihilation channel $\nu \overline{\nu }\to e^{-}{e}^{+}$ outside the Euler-Heisenberg-PFDM black hole. We find that the PFDM parameter contracts the optical structure, increases the oscillation frequency, enhances the damping rate, and suppresses transmission. On the other hand, the Euler-Heisenberg correction leads to a weaker near-horizon deformation whose effect becomes relevant for sufficiently large charge. These results provide a common scattering framework for comparing the impact of dark-matter environments and nonlinear electrodynamics on black-hole spectroscopic and radiative observables.

Black hole quasinormal modes are known to exhibit spectral instability under ultraviolet perturbations of the effective potential. In the present work, we investigate the sensitivity of the fundamental mode to different types of localized perturbations through a combination of analytic and numerical analyses. We show that the instability is governed primarily by the effective size of the perturbation rather than by its specific shape. In particular, the instability may persist even in the limit where the width of the perturbation vanishes, provided that the integrated strength of the perturbation is not zero. While a delta-function perturbation destabilizes the fundamental mode through an outward spiral, its interplay with a jump-discontinuity-type perturbation gives rise to competing inward and outward spiral motions. We further show that the stability of the fundamental mode depends sensitively on how the magnitude of the perturbation decreases as it moves away from the compact object, leading to qualitatively distinct outward spirals, inward spirals, and rotational trajectories. Finally, we investigate the motion of the fundamental mode in perturbed Regge-Wheeler potentials containing a jump discontinuity associated with a thin matter shell surrounding the black hole. The resulting behavior qualitatively resembles the spiral structure observed in double-sided Pöschl-Teller potentials, suggesting that the mechanisms identified in analytically tractable models persist in more realistic black hole effective potentials. The present results indicate that the spectral instability of low-lying black hole modes is considerably richer than previously anticipated and may have important implications for black hole spectroscopy in realistic astrophysical environments.

We study the large-$c$ expansion of general relativity in Arnowitt-Deser-Misner (ADM) variables. Using a unified even $\omega$-expansion, the ADM formulation gives a common starting point for Galilean and Carrollian limits. We focus on the Galilean branch and derive the ADM action and field equations up to next-to-next-to-leading order (NNLO). We then construct stationary vacuum solutions of the Galilean ADM equations up to NNLO in weak and strong branches. In the weak branch, we find next-to-leading order (NLO) Kerr-type, Hartle-Thorne-type and mixed-type solutions. The NLO weak equations also allow a simple extension to higher mass multipoles. At NNLO, the weak Kerr-type and extended Hartle-Thorne-type sectors solve the equations separately, but their naive sum is not a solution. The nonlinear NNLO equations generate mixed $J^{2}Q$ source terms, which require additional corrections to the NNLO lapse and NNLO spatial tensor field. This gives a mixed weak-branch Galilean solution of the truncated NNLO equations in the ADM gauge, whose full relativistic completion is not fixed by the truncated data alone. In the strong branch, Kerr-type data solve the equations through NNLO while the strong Hartle-Thorne-type data solve the NLO equations. We also explain how the ADM data can be reconstructed order by order into approximate spacetime metrics. These reconstructed metrics should not be interpreted by themselves as unique full relativistic completions. Since these metrics include spin, quadrupole and mixed spin–quadrupole effects, they may be useful for studying the spacetime around rotating compact objects such as black holes and neutron stars.

We study regular black hole solutions sourced by an anisotropic energy momentum tensor. It is well known that the geometry of the interior of a spherically symmetric regular black hole approaches the de Sitter metric. Having decomposed the energy momentum tensor into its isotropic and anisotropic components, we assume a hydrodynamic equation of state, $P=P(\rho )$, for the pressure, and look for spherically symmetric, regular black hole solutions. We consider different forms of $P(\rho )$ which yield the previously known regular black hole solutions, as well as various new metrics. We show that the profile of $P(\rho )$ has a root and a maximum as it approaches $0^{+}$ at large distances. Consequently, the square of the sound speed of perturbations, $c_s^2$, changes sign at the point where $P$ reaches its maximum, indicating a potential hydrodynamic instability. In addition, imposing the subluminal bound on $c_s$ puts strong constraints on the model parameters, excluding models in which the energy density has an exponential falloff. We establish a universal hierarchy among the relative positions at which the strong energy condition is violated, at which $P$ has its root, and at which $P$ attains its maximum.

Black hole shadow images are primarily determined by the properties of photon spheres and can exhibit degeneracies across different spherically symmetric spacetime geometries. We show that time delay observables associated with higher-order images of transient sources provide a robust probe to break such degeneracies in spacetimes admitting multiple photon spheres. Adopting a theory-agnostic, parametrized, static, spherically symmetric framework that captures the generic features of double-peak effective potentials, we investigate photon geodesics and quantify them in terms of angular deflection, travel time, and the order of the image. We identify distinctive signatures of trajectories probing the region between the unstable photon spheres. In particular, we find that these trajectories are characterized by the nontrivial temporal behavior, including a minimum travel time, a minimum angular deflection, and a characteristic triplet structure of higher-order images with a specific arrival sequence. We further show that the influence of the depth of the potential well, between the two photon spheres, on the observed time delays provides a direct handle on otherwise inaccessible regions of the spacetime. Although we consider a parametrized framework, these identified signatures are primarily influenced by the potential structure and will therefore occur in any spacetime with a similar double-peak effective potential. Our results highlight that time-domain lensing observables encode information beyond static shadow images and offer a promising avenue for probing the structure of compact objects and the strong-field regime of gravity.

We present a compressed Gaussian likelihood for the Planck cosmic microwave background (CMB) low-$\ell$ E-mode polarization data, constructed from the SRoll2 likelihood which provides a state-of-the-art constraint on the reionization optical depth $\tau$ to date. The non-Gaussian form of CMB low-$\ell$ temperature (TT) and E-mode polarization likelihoods makes them incompatible with Fisher matrix analyses that require an analytic Gaussian ${\chi }^2$, such as the Fisher-bias formalism and Fisher forecasts. We show that the ${\chi }^2$ of an offset log-normal likelihood takes a Gaussian form in the log-transformed power spectrum amplitudes, and can therefore be used directly in Fisher matrix analyses without any explicit change of variables. Building on this, we compress the SRoll2 likelihood into a small number of piecewise offset log-normal functions and validate it against the full SRoll2 likelihood via Markov chain Monte Carlo (MCMC) combined with Planck and ACT DR6 data, finding excellent agreement across all lambda cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) parameters and in extended cosmological models. We further demonstrate that Fisher matrix uncertainty estimates from our compressed likelihood agree well with the full MCMC posteriors. We release our compressed likelihood planck-gaussian-lowl, a lightweight Python package incorporating the compressed low-$\ell$ TTlikelihood from previous work, allowing a straightforward incorporation of the Planck CMB low-$\ell$ data into any Gaussian-likelihood-based analysis.

Identifying new observational probes to constrain cosmological parameters has become an important goal in modern cosmology. In this work, we explore the potential of the cosmic star formation rate density (SFRD), compiled over the redshift range $z\in [0,15]$, as a complementary probe of fundamental parameters, including ${\mathrm{\Omega }}_{\mathrm{m}}$, $H_0$, and the dark energy equation-of-state parameter, $w$. Within the $\mathrm{\Lambda }\mathrm{CDM}$ framework, SFRD combined with big bang nucleosynthesis (BBN) data alone yields $H_0=65\pm 11\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$, reflecting significant degeneracies with astrophysical parameters. By jointly analyzing SFRD with recent BAO and Type Ia supernova (SNIa) data, these degeneracies are effectively broken, resulting in much tighter constraints; e.g., SFRD + BBN + DESI-DR2 gives $H_0=68.28\pm 0.18\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$. We perform a statistical reconstruction of the SFRD as a function of redshift, finding a peak at $z_{\mathrm{peak}}=2.600_{-0.087}^{+0.114}$ within $\mathrm{\Lambda }\mathrm{CDM}$. We perform additional tests and find that the inferred value depends on the adopted SFRD parametrization. Our results demonstrate that combining SFRD with established cosmological probes not only improves constraints on cosmological parameters but also reduces uncertainties in astrophysical parameters governing star formation. We further extend the analysis to the $w\mathrm{CDM}$ model, highlighting the promise of SFRD as a robust complementary cosmological probe across different dark energy scenarios.

X-ray spectroscopy of active galactic nuclei (AGN) reveals key information about the circumnuclear matter geometry. Many AGN are known to show a narrow Fe $\mathrm{K}\alpha$ line at 6.4 keV and associated Compton-scattered continua in their x-ray spectra, due to primary continuum scattering in cold, neutral material far from the central supermassive black hole. We present a novel approach that uses simulation-based inference (SBI) with neural posterior estimation to train a machine learning (ML) model based on Nuclear Spectroscopic Telescope Array (NuSTAR) spectral fitting results from the literature, employing the physically motivated mytorus-decoupled model, which distinguishes line of sight from global equivalent neutral hydrogen column density ($N_{\mathrm{H},\mathrm{Z}}$ vs $N_{\mathrm{H},\mathrm{S}}$). To overcome the limitations of traditional frequentist fitting—such as lack of automation, reproducibility, and computational cost—we implement normalizing flows and autoregressive networks to learn flexible posterior distributions from simulated spectra. From 34 NuSTAR spectral fitting results reported in the literature, we generated 34,000 synthetic spectra for both a uniform and a Gaussian parameter distribution and show that the latter is more strongly observationally driven. We train our neural network to determine four key MYTORUS parameters, $N_{\mathrm{H},\mathrm{Z}}$, $N_{\mathrm{H},\mathrm{S}}$, power-law spectral index $\mathrm{\Gamma }$, and relative normalization $A_S$. Mutual information analysis identifies optimal spectral regions and justifies the inclusion of redshift, exposure time, and Galactic absorption. The observation-based grid significantly outperforms uniform sampling, achieving predictive accuracy for individual parameters greater than 90% ($N_{\mathrm{H},\mathrm{S}}$ and $A_S$), 89% ($N_{\mathrm{H},\mathrm{Z}}$), and 82% for $\mathrm{\Gamma }$ within $\pm 1\sigma$. For all four parameters simultaneously, predictive accuracy remains high at $\sim 70\%$. We make ml_mytorus, the trained model, publicly available with a web interface that enables fast and reproducible parameter inference from NuSTAR spectra. Its application to NGC 4388 illustrates the promise of the approach. ml_mytorus offers a reproducible and accessible alternative for exploring MYTORUS-type models and performs well in a statistical sense, highlighting the potential of SBI methods for future studies of distant x-ray reflection in x-ray spectra of AGN and potentially other compact accreting x-ray sources such as Galactic x-ray binaries.

Parker Solar Probe observations near the Sun reveal frequent, sudden reversals of the magnetic field known as switchbacks (SBs). Despite their ubiquity, the internal plasma structure and associated heating within SBs remain poorly understood. We present a case study of two closely spaced SBs (referred to in the text as ${\mathrm{SB}}_1$ and ${\mathrm{SB}}_2$) observed on 24 January 2020 using high-cadence magnetic and plasma measurements. Magnetic fluctuations are decomposed into components parallel and perpendicular to the mean field, and their power spectra are analyzed to characterize the turbulent cascade. The partial variance of increments method is applied to identify intermittent current sheetlike features. Both SB intervals exhibit clear Alfvénic behavior and enhanced radial flow; however, their microphysics differ: ${\mathrm{SB}}_1$ shows a higher proton temperature, larger fluctuation amplitudes, and a denser population of current sheets compared to ${\mathrm{SB}}_2$. The two events also differ in spectral index, with ${\mathrm{SB}}_1$ exhibiting a steeper perpendicular slope than ${\mathrm{SB}}_2$. The elevated intermittency, proton temperature, and transient $\beta >1$ excursion in ${\mathrm{SB}}_1$ suggest that localized dissipation at small-scale structures is a plausible driver of the observed heating. These findings demonstrate that SBs are not uniform kinematic deflections but dynamically evolving plasma structures whose internal turbulence may regulate local energy conversion and contribute to the spatially intermittent heating of the near-Sun solar wind.

We report the first search for high-energy neutrino emissions from dark matter (DM) annihilation in stellar-stream cores. Motivated by a recent gamma-ray study that proposed these cores as a new class of indirect DM targets, we analyze three stream cores in the Northern Hemisphere using the public ten-year tracklike neutrino data released by IceCube. Under the $\chi \chi \to \nu \overline{\nu }$ annihilation hypothesis, the most significant excess among the three targets is found at the position of the nearby dwarf galaxy Boötes III, the core of the Styx stream, with the DM mass of $m_{\chi }\simeq 10–31\mathrm{TeV}$. The excess has a posttrial significance of $3.1\sigma$. Considering the existing IceCube dwarf-galaxy limit for the same channel, we obtain a limit on the J-factor $J_{\mathrm{ann}}$, ${\log }_{10}(J_{\mathrm{ann}}/{\mathrm{GeV}}^2{\mathrm{cm}}^{-5})\gtrsim {19.1}_{-0.6}^{+0.3}$. This limit is broadly consistent with empirical estimates of $J_{\mathrm{ann}}$ for Boötes III. The results provide the first candidate target with a possible high-energy neutrino signal associated with DM annihilation. This neutrino excess and the general existence of DM-induced neutrino signals from other similar sources will be confirmed with the near-future large high-energy neutrino detectors, thus enabling us to probe the nature of DM particles.

Following the recent Atacama Cosmology Telescope results, we consider hilltop inflation where the inflaton is coupled to a curvaton, simultaneously addressing two main challenges faced by conventional hilltop inflation models: the initial-value problem; and their viability for sub-Planckian field values. In standard single-field hilltop inflation, the inflaton must start extremely close to the maximum of the potential, raising concerns about the naturalness of the initial conditions. We demonstrate that the curvaton field not only significantly relaxes the initial-value tuning required for hilltop inflation but also opens up parameter space through modifying the curvature perturbation power spectrum, reviving the quartic hilltop inflation model in the sub-Planckian regime. We find viable parameter space consistent with the recent cosmological observations.

The hadronic tensor encodes crucial information regarding the internal structure of hadrons, reflecting the nonperturbative features of quantum chromodynamics (QCD). In this work, we directly compute the hadronic tensor within ($1+1$)-dimensional U(1) and SU(2) gauge theories by evaluating real-time current-current correlation functions. Utilizing quantum algorithms executed on classical hardware, we demonstrate that the hadron form factors for both meson and baryon states can be reliably extracted from the hadronic tensor. Our methodology is validated by strong agreement with both direct calculation and exact diagonalization of the form factors.

Neutrino experiments are currently limited by low statistics, sizable systematic uncertainties, and coarse observable binning, which can hinder discrimination among competing beyond-the-Standard-Model (BSM) explanations of anomalous signals. In particular, analyses based primarily on total event-rate differences are vulnerable to source-normalization uncertainties and to degeneracies among models that induce similar inclusive yields. Using stopped-pion coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) as a benchmark environment, we study how much model-discrimination power can be obtained from correlations in baseline, recoil energy, and timing that are less sensitive to the total rate. As benchmark BSM scenarios, we consider a $3+1$ sterile-neutrino framework and neutral-current nonstandard neutrino interactions (NSI). We show with a likelihood-based analysis that these scenarios can be distinguished in nontrivial regions of parameter space once multidimensional shape information is retained. We further demonstrate with convolutional neural networks that substantial discrimination remains possible even after the total event rate is explicitly removed from the input, indicating that the relevant information is genuinely encoded in the shape of the $\mathrm{CE}\nu \mathrm{NS}$ distribution. Finally, through multiclass classification within the sterile parameter space, we show that in favorable regions the same observables can support approximate localization of the underlying sterile-neutrino benchmark point. Our results highlight the complementary roles of conventional and machine-learning-based inference in moving neutrino new-physics searches from anomaly detection to physics interpretation.

We investigate neutrino mass and thermal leptogenesis in the Babu-Nandi-Tavartkiladze model featuring a scalar quadruplet ($\mathrm{\Phi }$) and a pair of vectorlike fermion triplets ($\mathrm{\Sigma }$). In this framework, neutrino masses are generated via an effective dimension-7 operator $LLHH(H^{†}H)/{\mathrm{\Lambda }}^3$ at the tree level and via the dimension-5 operator $LLHH/\mathrm{\Lambda }$ at the one-loop level. It naturally accommodates sub-eV neutrino masses even if the new physics scale $\mathrm{\Lambda }$ is $\mathcal{\text{O}}(\mathrm{TeV})$, thus making the model a compelling target for experimental searches. We explore the viability of thermal leptogenesis in this model, which is distinct from the canonical seesaw-based leptogenesis due to the presence of vector-like fermions. We find that leptogenesis is viable for $M_{\mathrm{\Sigma }}\gtrsim {10}^7\mathrm{GeV}$ for a hierarchical spectrum of fermion triplets. However, in the quasidegenerate regime, resonant enhancement of the $\mathrm{CP}$ asymmetry lowers this scale down to $\mathcal{O}(\mathrm{TeV})$, reconciling successful leptogenesis with the originally motivated TeV-scale phenomenology and testability of the model at colliders.

We present a unified theoretical study of semileptonic decays of ground state octet hyperons using the relativistic three-quark model (R3QM). A key innovation of our approach is that all baryon wave functions are determined by fitting the baryon mass spectrum with a semirelativistic potential model, leading to predictions for weak transition amplitudes without free parameters. Adopting these wave functions, we calculate the decay widths, branching fractions, lepton flavor universality ratios, as well as the angular correlation and spin asymmetry parameters for the octet channels. The calculated values agree with the available experimental data and give predictions for channels with limited experimental information. We further compute the complete set of octet transition form factors without any additional free parameters, so that the weak current can be examined beyond the rate observables. In the well measured $\mathrm{\Lambda }\to p{\ell }^{-}{\overline{\nu }}_{\ell }$ channel, the calculated leading vector and axial-vector form factors, $f_1(0)$ and $g_1(0)$, agree well with recent lattice QCD results, and the $g_1/f_1$ ratio is consistent with recent BESIII measurements. Beyond the leading vector and axial-vector terms, the complete form factor set separates the weak magnetism, second class, and the pole contribution associated with the partially conserved axial current (PCAC) relation. The weak magnetism term $f_2$ shows the clearest channel dependence compared with lattice QCD results, and its smaller values in some channels may point to transverse current strength not fully saturated by pure $qqq$ valence components. This work provides a framework for connecting octet hyperon weak form factors to the spin-flavor and spatial structure of baryons at the quark level, and gives testable weak current observables for future hyperon semileptonic decay measurements.

We compute generalized susceptibilities of conserved charges in the Polyakov chiral SU(3) quark mean field (PCQMF) model with the fermion vacuum term. At ${\mu }_B=0\mathrm{MeV}$, the calculation covers the diagonal ${\chi }_n^{B,Q,S}$ through eighth order and all twelve independent fourth-order off-diagonal correlators. Extending to finite ${\mu }_B$ at ${\mu }_Q={\mu }_S=0$, we compute ${\chi }_n^B$ through eighth order, ${\chi }_n^{Q,S}$ through fourth order, the second-order off-diagonals, all twelve fourth-order off-diagonal correlators, and the odd-order baryon susceptibilities ${\chi }_1^B$, ${\chi }_3^B$, ${\chi }_5^B$. The calculation includes the vacuum term ($\mathrm{vac}=1$) and is repeated for an independently refitted no-sea variant ($\mathrm{vac}=0$). At ${\mu }_B=0\mathrm{MeV}$, the chiral pseudocritical temperature is $T_{\mathrm{pc}}=170.5\mathrm{MeV}$ ($\mathrm{vac}=1$) and 166.4 MeV ($\mathrm{vac}=0$), while the Polyakov-loop deconfinement temperature is $T_{\mathrm{dec}}=144.4\mathrm{MeV}$ ($\mathrm{vac}=1$) and 146.6 MeV ($\mathrm{vac}=0$). In $\mathrm{vac}=1$, the derivative $-d{\mathrm{\Delta }}_{l,s}/dT$ of the subtracted chiral condensate develops an inflection near $T_{\mathrm{dec}}$. Higher derivative orders resolve the chiral-deconfinement splitting as twin maxima in ${\chi }_4^B$ and ${\chi }_6^Q$, twin minima in ${\chi }_8^B$ and ${\chi }_8^Q$, and multiple zero crossings in ${\chi }_6^B$. Among the fourth-order off-diagonal correlators, $\mathrm{vac}=1$ amplitudes exceed $\mathrm{vac}=0$ in the baryon-charge channel across the chiral crossover. The baryon-strangeness, charge-strangeness, and mixed baryon-charge-strangeness components peak near the strange-melting temperature, where $\mathrm{vac}=0$ dominates. Along $T_{\mathrm{pc}}({\mu }_B)$, the kurtosis ratio $R_{42}^B\equiv {\chi }_4^B/{\chi }_2^B$ of $\mathrm{vac}=1$ crosses zero at ${\mu }_B/T_{\mathrm{pc}}\approx 2.15$ for ${\mu }_Q={\mu }_S=0$ and at $\approx 2.47$ under the heavy-ion constraints of strangeness neutrality and $n_Q/n_B=0.4$, while $\mathrm{vac}=0$ stays positive in both cases over ${\mu }_B\le 500\mathrm{MeV}$. The higher-order ratios $R_{51}^B\equiv {\chi }_5^B/{\chi }_1^B$ and $R_{62}^B\equiv {\chi }_6^B/{\chi }_2^B$ start negative in $\mathrm{vac}=1$ and grow more negative as ${\mu }_B$ increases.