We propose a novel, machine-learning-based framework for constructing lattice fermions using physics-informed neural networks (PINNs). Our approach treats the formulation of the Dirac operator as an optimization problem guided by physical requirements, such as symmetries, locality and doubler-decoupling conditions. We first demonstrate that, when trained to satisfy the Ginsparg-Wilson (GW) relation as a soft constraint, a neural network reproduces the overlap fermion operator to high numerical accuracy and learns an effective sign-function mapping without explicitly using a prescribed polynomial or rational approximation. Second, we extend the framework from operator construction to machine-assisted algebraic discovery. Within a generalized polynomial ansatz, the network autonomously drives higher-order terms to zero and recovers the standard Ginsparg-Wilson relation. Remarkably, by changing the initial search bias, the same framework also finds a distinct solution corresponding to a Fujikawa-type generalized GW relation.

We determine the interaction potential of a solitonic dipole in the singlet state, modeled as an SU(2) field, using improved lattice simulations of two stationary solitons at varying separations. The potential is extracted from the energy of two-soliton configurations as a function of distance. At large separations, the interaction reproduces the classical Coulomb potential quantitatively up to an energy shift $\delta E_{\infty }\approx 9\mathrm{keV}$ of the fitted asymptotic constant relative to $2m_e{c}_0^2$, assumed to be related to limited numerical precision on the lattice. At shorter distances, deviations from the Coloumb potential of pointlike charges appear, that are in qualitative agreement with the asymptotic formula of perturbative quantum electrodynamics, reflecting the running of the fine-structure constant, with the inverse fine-structure constant (${\alpha }^{-1}\approx 137$) reproduced.

Construction of creation operators which can properly sample the underlying energy eigenstates remains a fundamental first step in lattice QCD spectroscopy calculations, particularly when the spectrum includes states with different compositions such as mesons, glueballs, multiparticle states, etc. We tackle this issue in the study of the scalar glueball and charmonium mixing, where we use improved operators for both types of states to resolve the low-lying spectrum and identify the dominant composition of each state in a mass regime where the glueball is stable. We include derivative-based meson operators combined with distillation profiles, as well as glueball operators built from the chromomagnetic field and its derivatives which retain angular momentum information from their continuum counterparts. We comment on the advantages of these operators, particularly on the construction and implementation of the glueball ones, thanks to which we identify the lightest isoscalar state as glueball-dominated $0^{++}$.

Four-dimensional chiral gauge theory can be formulated as the boundary theory on a five-dimensional manifold in a manner that may be realized on a finite lattice. There are interesting features of these theories that defy a purely four-dimensional conception of universality. We find that QCD when embedded in a chiral gauge theory (the Standard Model) and regulated this way can simultaneously avoid both the $U(1{)}_A$ problem and the strong $CP$ problem, with a central role played by fermion zero modes localized far away in the fifth dimension. In this way it differs from conventional lattice QCD formulated as a stand-alone theory, universality being violated by inaccessible light modes in the five-dimensional bulk. Our analysis builds on recent work by others that highlights the role of global $U(1)$ symmetries in five-dimensional formulations of four-dimensional chiral gauge theories, and the generic appearance of fermion zero modes in the bulk.

We present a determination of the scalar and tensor $\mathrm{\Lambda }\to p$ transition form factors using lattice QCD. These form factors are relevant for semileptonic hyperon decays in the presence of extensions of the Standard Model that include scalar and tensor interactions. The calculation is carried out using a gauge ensemble of twisted mass fermions at the physical pion mass, following the same strategy as our recent study on vector and axial form factors for the same transition [S. Bacchio and A. Konstantinou, Phys. Rev. Lett. 135, 231901 (2025)]. We provide the complete set of form factors as functions of $q^2$ employing a model-independent parametrization. We examine their impact on searches for nonstandard charged-current interactions via the muon-to-electron decay-rate ratio $R^{\mu e}=\mathrm{\Gamma }(\mathrm{\Lambda }\to p\mu {\overline{\nu }}_{\mu })/\mathrm{\Gamma }(\mathrm{\Lambda }\to pe{\overline{\nu }}_e)$, where scalar and tensor contributions enter linearly and are helicity enhanced relative to the electron channel. We compare this first-principles prediction for the decay-rate ratio with recent experimental measurements, thereby enabling improved constraints on nonstandard charged-current interactions.

Anomaly detection has the potential to discover new physics in unexplored regions of the data. However, choosing the best anomaly detector for a given dataset in a model-agnostic way is an important challenge which has hitherto largely been neglected. In this paper, we introduce the data-driven ARGOS metric, which has a sound theoretical foundation and is empirically shown to robustly select the most sensitive anomaly detection model given the data. Focusing on weakly supervised, classifier-based anomaly detection methods, we show that the ARGOS metric outperforms other model selection metrics previously used in the literature, in particular the binary cross-entropy loss. We explore several realistic applications, including hyperparameter tuning as well as architecture and feature selection. In all cases, we demonstrate that ARGOS is highly sensitive to the small amounts of signal present in anomaly detection analyses while at the same time being robust to background overfitting and background template mismodeling.

We study the heavy quark dynamics in the presence of memory within the framework of a generalized Langevin equation. Time correlated thermal noise with power-law decay is generated by a fractional differential equation, formulated using the Caputo fractional derivative with order parameter $\nu$. The effect of memory is calculated through the momentum correlation, the time evolution of the average squared momentum, the average squared displacement, and the average kinetic energy. The effect of memory is further studied for the higher normalized central moments of the heavy quark transverse-momentum distribution. The results indicate that time correlated thermal noise substantially influences heavy quark dynamics in the quark gluon plasma.

In this work, to establish a more abundant ${\mathrm{\Lambda }}_c$ baryon spectrum, we discuss the production potentials of the excited ${\mathrm{\Lambda }}_c$ baryons through ${\mathrm{\Lambda }}_b$ hadronic weak decays within a constituent quark model. Based on our successful explanations of the existing experimental data for the ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c({\pi }^{-},K^{-},D^{-},D_s^{-},D_s^{*-})$ processes, we further calculate the decay rates of the ${\mathrm{\Lambda }}_b$ baryon into the $1P$-, $1D$-, $2S$-, $3S$-, $2P$-, $1F$-, and $2D$-wave ${\mathrm{\Lambda }}_c$ excited states. It is found that these ${\mathrm{\Lambda }}_c$ excitations have large production rates in the ${\mathrm{\Lambda }}_b$ hadronic weak decay process associated with ${\pi }^{-}$ meson emitting, i.e., ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c^{*}{\pi }^{-}$, their branching fractions can reach up to $\mathcal{O}({10}^{-3})$. To search for the higher $3S$-, $2P$-, $1F$-, and $2D$-wave ${\mathrm{\Lambda }}_c$ states, the ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c(3S){\pi }^{-}\to D^{*0}p{\pi }^{-}$, and ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c(2P,2D,1F){\pi }^{-}\to D^{(*)0}p{\pi }^{-}$ decays are worth observing in future experiments.

In this work, we first present a systematic investigation of the $T_{\overline{c}\overline{s}}$-type charmed-strange molecular tetraquark candidates composed of a $K^{(*)}$ meson and a $T$-doublet anticharmed meson using the one-boson-exchange model, which exhibit exotic flavor content $\overline{c}\overline{s}qq$. Our results suggest that the $K^{*}{\overline{D}}_1$ states with $I(J^P)=0(0^{-},1^{-})$ and the $K^{*}{\overline{D}}_2^{*}$ states with $I(J^P)=0(1^{-},2^{-})$ represent the most promising candidates of the $T_{\overline{c}\overline{s}}$-type charmed-strange molecular tetraquarks, while the coupled $K{\overline{D}}_1/K^{*}{\overline{D}}_1/K^{*}{\overline{D}}_2^{*}$ system with $I(J^P)=0(1^{-})$ and the coupled $K{\overline{D}}_2^{*}/K^{*}{\overline{D}}_1/K^{*}{\overline{D}}_2^{*}$ system with $I(J^P)=0(2^{-})$ can only be regarded as the possible candidates of the $T_{\overline{c}\overline{s}}$-type charmed-strange molecular tetraquarks. We further extend our analysis to the $K^{(*)}{D}_1/K^{(*)}{D}_2^{*}$ systems, where our results suggest a series of $T_{c\overline{s}}$-type charmed-strange molecular tetraquark candidates. These findings provide a comprehensive picture of the molecular spectrum in the charmed-strange tetraquark sector composed of $S$-wave kaons and (anti)charmed mesons in the $T$-doublet and can be tested in future experimental studies.

There is an apparent contradiction in the current literature about the effect of rotation in the quark-gluon plasma (QGP). While results from lattice QCD predict an increase in the confinement/deconfinement critical temperature, approximated calculations, and effective models, including holographic ones, lead to the opposite result. Noncentral heavy ion collisions form QGPs with relativistic rotational velocities. Thereby, a great interest was drawn into the effect of rotation in strongly interacting matter. In this work, we show that the apparent contradiction is associated with the choices of the observer considered in each case. We consider a holographic description of a rotating plasma using a Myers-Perry black hole. For a static observer, the result is that the confinement/deconfinement temperature decreases with the angular velocity, while for an observer corotating with the plasma the opposite behavior is found, in agreement with lattice calculations.

Neutrons are important final-state particles in neutrino interactions, yet they are not considered or reconstructed in most current neutrino liquid argon time projection chamber (LArTPC) physics analyses. In this paper, we present a simulation-based proof-of-concept study of neutron reconstruction in a generic LArTPC detector. Leveraging isolated, MeV-scale energy deposits, or blips, from neutron inelastic scattering, and using realistic blip response from published experimental results, we demonstrate the capability to identify neutrons and to reconstruct the direction and energy of the final-state neutron system in sub-GeV neutrino interactions. We then explore how neutron-related blip attributes can be used to improve physics studies of neutrino interactions, such as enhancing neutrino-antineutrino separation in atmospheric neutrinos and reverse-horn-current beam neutrinos. This study provides an initial quantification of LArTPC neutron reconstruction capabilities, which we expect to improve with future advancements in blip reconstruction, identification, and classification algorithms, as well as the modeling of neutrons.

Conformal blocks in odd spacetime dimensions are not known in closed analytic form. To facilitate efficient computations in the conformal bootstrap, we introduce goblocks: a novel conformal-block generator implemented in the Go programming language, designed for rapid, on-the-fly, parallel evaluation in general spacetime dimensions using recursive relations. The package supports both multipoint and derivative-based bootstrap approaches and allows flexible control over accuracy and performance. We benchmark goblocks against the scalar_blocks package, finding significant speed improvements in applications where computational speed and moderate accuracy are critical, but ultrahigh precision is not essential. As an illustration, we apply goblocks to the mixed-correlator bootstrap of the three-dimensional Ising model, formulated as a nonconvex optimization problem in a suitable truncation scheme. We simultaneously optimize over external scaling dimensions and OPE CFT data. In addition, we discuss how the approach scales as we increase the number of mixed correlators in more general $O(N)$ vector models.

We study the nonlocal effective action of a massless scalar field defined on a flat manifold with a curved boundary. Using a heat-kernel approach, we derive a covariant expansion of the nonlocal contribution to quadratic order in the extrinsic curvature tensor. Our construction provides a geometric framework that both reproduces earlier results obtained for Monge-patch embeddings and extends them to more general surfaces that need not admit a global Monge-patch description. The expansion is valid in the regime where gradients of the extrinsic curvature dominate over nonlinear curvature effects. As an application, we compute the particle-creation rate for an oscillating deformed ring in $2+1$ dimensions and an oscillating deformed sphere in $3+1$ dimensions.

Minkowski spacetime exhibits infrared instability in projectable Hořava gravity in ($3+1$) dimensions. To be phenomenologically viable, the instability should be either hidden by other time-dependent processes such as the Hubble expansion of the universe and the Jeans instability, or evolve into another static solution with low average curvature. While the former scenario leads to a phenomenological constraint on the infrared properties of the renormalization group flow, this paper explores the latter possibility. We study if the presence of higher derivative terms in the action can lead to the existence of static, inhomogeneous (quasi)periodic solutions with planar symmetry, similar to modulated phases in magnetic materials. We find that such solutions do not exist. In doing so, we classify all static homogeneous and isotropic solutions and solutions with planar symmetry. We provide arguments that none of them can serve as an endpoint for the evolution of the Minkowski instability. This motivates further study of the scenario where the instability is concealed by time evolution.

The detection of GW230529_181500 suggested the existence of more symmetric black hole-neutron star mergers where the black hole mass can be as low as 2.6 times that of the neutron star. Black hole-neutron star binaries with even more symmetric mass ratios are expected to leave behind massive disks capable of driving bright electromagnetic transients like kilonovae. Currently, there is only a limited number of numerical-relativity simulations of black hole-neutron star mergers in this regime, which are vital for accurate gravitational waveform models and analytical fitting formulas for the remnant properties. Insufficient accuracy of these may lead to misclassification of real events and potentially missed opportunities to locate their electromagnetic counterparts. To fill this gap in the parameter space coverage, we perform simulations of black hole-neutron star mergers with mass ratios $q\in \{1,1/2,1/3\}$. We find the gravitational waveform models do not show good agreement with the numerical waveforms, with dephasing at the level of around 1 rad at the merger. We find that the masses of the dynamical ejecta and disk are in good agreement with the available fitting formulas. The analytical formulas for the remnant black hole are in excellent agreement for the black hole mass, but are less accurate with the predictions for its spin. Moreover, we analyze the remnant disk structure and dynamics, deriving the rotation law and identifying global trapped $g$ mode density oscillations. We distinguish three types of accretion in the postmerger and find modulation of the accretion rate by the global oscillations of the disk. Finally, we model the kilonova emission these systems would produce and find that most of them are potentially detectable by the Vera C. Rubin Observatory within four days after merger, and by DECam within two days after merger if located at a distance of 200 Mpc.

The space mission LISA, scheduled for launch in 2035, aims to detect gravitational wave (GW) signals in the milli-Hz band. In the context of the ESA Voyage 2050 Call for new mission concepts, other frequency ranges are explored by the Gravitational-Wave Space 2050 Working Group to conceive new proposals for a post-LISA space-based detector. In this work, we give a preliminary estimate of the observational potential of three mission designs proposed in the literature, namely, $\mu \mathrm{Ares}$, AMIGO and the Decihertz Observatory. The analysis framework includes astrophysical GW sources, such as massive black hole binaries and extreme mass-ratio inspirals, and compact binaries, such as stellar black holes and white dwarfs. For each detector, we first present a consistent computation of the unresolved gravitational wave background (GWB) produced by the sum of all anticipated astrophysical populations using an iterative subtraction algorithm. We then investigate which types of systems are the most appealing by measuring the number of GW signals detected and exploring the source properties.

This paper investigates the crucial role of parton distribution functions (PDFs) in high-energy physics, particularly their impact on the extraction of generalized parton distributions (GPDs) at zero skewness. To this aim, we perform six global analyses of GPDs using different modern PDF sets (NNPDF40, CT18, and MSHT20) at three specific factorization scales ($\mu =2$, 1.3, and 1 GeV) and different perturbative orders. A wide range of elastic electron scattering data is included in the analysis to constrain GPDs in a broad interval in the momentum transfer squared $t$. The analyses reveal that the best overall description of experimental data is achieved using NNPDF40 PDFs at the next-to-leading order (NLO), with moderate sensitivity to the choice of PDF input, especially in the region of low $t$. The dependence on the perturbative order is relatively mild, indicating stability in the extraction procedure. We also show that different GPD sets become more consistent at larger $|t|$ values, with down-quark GPDs experiencing greater suppression than up-quark GPDs. We show that the differences among the GPD parametrizations propagate into measurable quantities such as proton radii, leading to non-negligible variations in the extracted central values and uncertainties. The six extracted GPD sets, available at different scales and perturbative orders, provide valuable resources for future theoretical and phenomenological studies, offering flexibility for researchers in exploring the proton’s internal structure.

Using a data sample of $(1.0087\pm 0.0044)\times {10}^{10}$ $J/\psi$ events collected with the BESIII detector, we study the rare double Dalitz decay of $\eta \to e^{+}{e}^{-}{e}^{+}{e}^{-}$ through the processes $J/\psi \to \gamma \eta$ and $J/\psi \to \gamma {\eta }^{\prime },{\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}\eta$. Clear $\eta$ signals are observed in the $e^{+}{e}^{-}{e}^{+}{e}^{-}$ invariant mass spectrum, with statistical significances of $5.9\sigma$ and $7.8\sigma$ for the two channels, respectively. By combining both modes, we determine the branching fraction of $\eta \to e^{+}{e}^{-}{e}^{+}{e}^{-}$ to be $(2.63\pm 0.34_{\mathrm{stat}}\pm 0.16_{\mathrm{syst}})\times {10}^{-5}$. The result is consistent with the previous measurements within uncertainties and further constrains physics beyond the standard model.

In this paper, we present a comprehensive analysis of the differential equations governing the spatial profile of the ’t Hooft–Polyakov monopole from the viewpoint of resurgence theory. We note that the universality of the gauge-component asymptotics, together with the relative simplicity of its Borel transform and the associated Volterra equations’ kernels, gives rise to a perturbative expansion featuring a good control over the proliferation of the Borel-plane singularities to all orders, along with useful information about their structure. Moreover, its partial resummation reveals remarkably simple universal analytic “dressed” background, around which one may develop a global perturbative expansion of the exact solutions for any $\lambda /e^2>0$ and, at least in principle, get a grip on the numerical parameters governing the local expansions of the profile functions.

We use a canonical parametrization of twisted geometries describing the classical phase space of loop quantum gravity on a fixed graph, and establish its explicit correspondence with the associated frame bases and spinorial descriptions. Applied to the two-vertex model, this framework yields analytical bounds on the evolution of the total area, proving the existence of a nonvanishing lower bound at finite times. These findings, previously observed only numerically, suggest a bouncelike behavior and highlight the usefulness of these variables for the study of more general configurations. As a second result, the canonical variables are shown to simplify the gauge-fixing procedure, generalizing previous results restricted to two-vertex models with four links.