We present an investigation of pion-nucleon elastic scattering in the $I(J^P)=\frac{3}{2}({\frac{3}{2}}^{+})$ channel using lattice QCD with degenerate up and down, strange and charm quarks with masses tuned to their physical values. We use an ensemble of twisted mass fermions with box size $L=5.1\mathrm{fm}$ and lattice spacing $a=0.08\mathrm{fm}$ and we consider the $\pi N$ system in rest and moving frames up to total momentum ${\overrightarrow{P}}^2=3(2\pi /L{)}^2=0.17{\mathrm{GeV}}^2$. We take into account the finite volume symmetries and $S$- and $P$-wave mixing, and use the Lüscher formalism to simultaneously constrain the $J=1/2,\ell =0$ and $J=3/2,\ell =1$ scattering amplitudes. We estimate the $\mathrm{\Delta }$ resonance pole in the $P$-wave channel as well as the $S$-wave isospin-$3/2$ scattering length.

Recently, we made significant advancements in improving the computational efficiency of lattice QCD calculations for generalized parton distributions (GPDs). This progress was achieved by adopting calculations of matrix elements in asymmetric frames, deviating from the computationally-expensive symmetric frame typically used, and allowing freedom in the choice for the distribution of the momentum transfer between the initial and final states. A crucial aspect of this approach involves the adoption of a Lorentz covariant parametrization for the matrix elements, introducing Lorentz-invariant amplitudes. This approach also allows us to propose an alternative definition of quasi-GPDs, ensuring frame independence and potentially reduce power corrections in matching to light cone GPDs. In our previous work, we presented lattice QCD results for twist-2 unpolarized GPDs ($H$ and $E$) of quarks obtained from calculations performed in asymmetric frames at zero skewness. Building upon this work, we now introduce a novel Lorentz covariant parametrization for the axial-vector matrix elements. We employ this parametrization to compute the axial-vector GPD $\tilde{H}$ at zero skewness, using an $N_f=2+1+1$ ensemble of twisted mass fermions with clover improvement. The light-quark masses employed in our calculations correspond to a pion mass of approximately 260 MeV.

Weak magnetic field induced corrections for the Yukawa potential due to one pion exchange between two constituent quarks (nucleons) are presented. For that, the constant magnetic field effect on the pion propagator and on the pion form factor are taken into account. An effective gluon propagator parametrized with an effective gluon mass ($M_g\sim 0.5\mathrm{GeV}$) is considered. In the limit of magnetic field that is weak with respect to the constituent quark mass and pion mass, analytical and semianalytical expressions can be obtained. Different types of contributions are found, isotropic or anisotropic, dependent on the pion mass and also on the constituent quark and effective gluon masses. Overall the corrections are of the order of 2% to 5% of the Yukawa potential at distances close to 2 fm, and they decrease slower than the Yukawa potential. The anisotropic corrections are considerably smaller than the isotropic components. A sizable splitting between results due to the magnetic field dependent neutral or charged pion mass is found.

We evaluate the heavy quark momentum diffusion coefficients in a hot magnetized medium for the most general scenario of any arbitrary values of the external magnetic field. We choose to work with the systematic way of incorporating the effect of the magnetic field, by using the effective gluon and quark propagators, generalized for a hot and magnetized medium. To get gauge independent analytic form factors valid through all Landau levels, we apply the hard thermal loop technique for the resummed effective gluon propagator. The derived effective hard thermal loop gluon propagator and the generalized version of Schwinger quark propagator subsequently allow us to analytically evaluate the longitudinal and transverse momentum diffusion coefficients for charm and bottom quarks beyond the static limit. Within the static limit we also explore another way of incorporating the effect of the magnetic field, i.e. through the magnetized medium modified Debye mass and compare the results to justify the need for structural changes.

In this work, we study the multibaryon configurations in a simple chromomagnetic model. We first construct the wave function of the multibaryon states using the multiquark configuration. We consider all possible quantum numbers assuming the spatial part of the wave function to be totally symmetric. Then, we calculate the color-spin factors for tetrabaryons, pentabaryons, and hexabaryons in the flavor SU(3) breaking case and discuss its physical application.

Precision measurements of anomalous quartic couplings of electroweak gauge bosons allow us to search for deviations of the Standard Model predictions and signals of new physics. Here, we obtain the constraints on anomalous quartic gauge couplings using the presently available data on the production of gauge-boson pairs via vector boson fusion. We work in the Higgs effective theory framework and obtain the present bounds on the operator’s Wilson coefficients. We show that the combination of different datasets breaks the degeneracies in analysis with more than one nonvanishing Wilson coefficient. Anomalous quartic gauge boson couplings lead to rapidly growing cross sections and we discuss the impact of a unitarization procedure on the attainable limits.

The maximal cut of the nonplanar crossed box diagram with all massive internal propagators was long ago shown to encode a hyperelliptic curve of genus 3 in momentum space. Surprisingly, in Baikov representation, the maximal cut of this diagram only gives rise to a hyperelliptic curve of genus 2. To show that these two representations are in agreement, we identify a hidden involution symmetry that is satisfied by the genus 3 curve, which allows it to be algebraically mapped to the curve of genus 2. We then argue that this is just the first example of a general mechanism by means of which hyperelliptic curves in Feynman integrals can drop from genus $g$ to $\lceil g/2\rceil$ or $\lfloor g/2\rfloor$. We find an algorithm to test for the presence of genus drop, and highlight further instances of this mechanism in Feynman integrals.

A light scalar $X_0$ or vector $X_1$ particles have been introduced as a possible explanation for the $(g-2{)}_{\mu }$ anomaly and dark matter phenomena. Using $(8.998\pm 0.039)\times {10}^{9}J/\psi$ events collected by the BESIII detector, we search for a light muon philic scalar $X_0$ or vector $X_1$ in the processes $J/\psi \to {\mu }^{+}{\mu }^{-}{X}_{0,1}$ with $X_{0,1}$ invisible decays. No obvious signal is found, and the upper limits on the coupling $g_{0,1}^{\prime }$ between the muon and the $X_{0,1}$ particles are set to be between $1.1\times {10}^{-3}$ and $1.0\times {10}^{-2}$ for the $X_{0,1}$ mass in the range of $1<M(X_{0,1})<1000\mathrm{MeV}/c^2$ at 90% credibility level.

Geodesy in a Newtonian framework is based on the Newtonian gravitational potential. The general-relativistic gravitational field, however, is not fully determined by a single potential. The vacuum field around a stationary source can be decomposed into two scalar potentials and a tensorial spatial metric, which together serve as the basis for general-relativistic geodesy. One of the scalar potentials is a generalization of the Newtonian potential while the second one describes the influence of the rotation of the source on the gravitational field for which no nonrelativistic counterpart exists. In this paper the operational realizations of these two potentials, and also of the spatial metric, are discussed. For some analytically given spacetimes the two potentials are exemplified and their relevance for practical geodesy on Earth is outlined.

In this paper, we study the impact of anisotropy on neutron stars with different equations of state, which have been modeled by a piecewise polytropic function with continuous sound speed. Anisotropic pressure in neutron stars is often attributed to interior magnetic fields, rotation, and the presence of exotic matter or condensates. We quantify the presence of anisotropy within the star by assuming a quasilocal relationship. We find that the radial and tangential sound velocities constrain the range of anisotropy allowed within the star. As expected, the anisotropy affects the macroscopic properties of stars, and it can be introduced to reconcile them with astrophysical observations. For instance, the maximum mass of anisotropic neutron stars can be increased by up to 15% compared to the maximum mass of the corresponding isotropic configuration. This allows neutron stars to reach masses greater than $2.5M_{\odot }$, which may explain the secondary compact object of the GW190814 event. Additionally, we propose a universal relation for the binding energy of an anisotropic neutron star as a function of the star’s compactness and the degree of anisotropy.

In the most extreme astrophysical environments, such as core-collapse supernovae (CCSNe) and neutron star mergers (NSMs), neutrinos can undergo fast flavor conversions (FFCs) on exceedingly short scales. Intensive simulations have demonstrated that FFCs can attain equilibrium states in certain models. In this study, we utilize physics-informed neural networks (PINNs) to predict the asymptotic outcomes of FFCs, by specifically targeting the first two moments of neutrino angular distributions. This makes our approach suitable for state-of-the-art CCSN and NSM simulations. Through effective feature engineering and the incorporation of customized loss functions that penalize discrepancies in the predicted total number of ${\nu }_e$ and ${\overline{\nu }}_e$, our PINNs demonstrate remarkable accuracies, with an error margin of $\lesssim 3\%$. Our study represents a substantial leap forward in the potential incorporation of FFCs into simulations of CCSNe and NSMs, thereby enhancing our understanding of these extraordinary astrophysical events.

We show that the maximum shower depth ($X_{\max }$) distributions of ultrahigh energy cosmic rays (UHECRs), as measured by fluorescence telescopes, can be augmented by building a mapping to observables collected by surface detectors. The resulting statistical improvement of such an augmented dataset depends in a universal way on the strength of the correlation exhibited by the mapping. Building upon the publicly available data on “golden hybrid” events from the Pierre Auger Observatory, we project possible improvements in the inferred composition of UHECRs for a range of possible mappings with varying correlation strengths.

Recent observations from several pulsar timing array (PTA) collaborations have unveiled compelling evidence for a stochastic signal in the nanohertz band. This signal aligns remarkably with a gravitational wave (GW) background, potentially originating from the first-order color charge confinement phase transition. Distinct quantum chromodynamics (QCD) matters, such as quarks or gluons, and diverse phase transition processes thereof can yield disparate GW energy density spectra. In this paper, employing the Bayesian analysis on the NANOGrav 15-yr dataset, we explore the compatibility with the observed PTA signal of the GWs from phase transitions of various QCD-matter scenarios in the framework of the holographic QCD. We find that the PTA signal can be effectively explained by the GWs from the confinement-deconfinement phase transition of pure quark systems in a hard-wall model of the holographic QCD where the bubble dynamics, one important source of the GWs, is of the Jouguet detonations. Notably, our analysis decisively rules out the plausibility of the pure gluon QCD-matter scenario and the nonrunaway bubble dynamics model for the phase transition in explaining the observed PTA signal.

The flexible method of reduction to finite integrals, briefly described in earlier publications of the author, is described in detail. The method is suitable for the calculation of all quantum electrodynamical contributions to the magnetic moments of leptons. It includes mass-dependent contributions. The method removes all divergences (UV, IR, and mixed) point-by-point in Feynman parametric space without any usage of limitlike regularizations. It yields a finite integral for each individual Feynman graph. The subtraction procedure is based on the use of linear operators applied to the Feynman amplitudes of UV-divergent subgraphs; a placement of all terms in the same Feynman parametric space is implied. The final result is simply the sum of the individual graph contributions; no residual renormalization is required. The method also allows us to split the total contribution into the contributions of small gauge-invariant classes. The procedure offers a great freedom in the choice of the linear operators. This freedom can be used for improving the computation speed and for a reliability check. The mechanism of divergence elimination is explained, as well as the equivalence of the method and the on shell renormalization. For illustrative purposes, all 4-loop contributions to the anomalous magnetic moments of the electron and muon are given for each small gauge-invariant class, as well as their comparison with previously known results. This also includes the contributions that depend on the ratios of the tau-lepton mass to the electron and muon mass.

Simulating particle detector response is the single most expensive step in the Large Hadron Collider computational pipeline. Recently it was shown that normalizing flows can accelerate this process while achieving unprecedented levels of accuracy, but scaling this approach up to higher resolutions relevant for future detector upgrades leads to prohibitive memory constraints. To overcome this problem, we introduce Inductive CaloFlow (icaloflow), a framework for fast detector simulation based on an inductive series of normalizing flows trained on the pattern of energy depositions in pairs of consecutive calorimeter layers. We further use a teacher-student distillation to increase sampling speed without loss of expressivity. As we demonstrate with datasets 2 and 3 of the CaloChallenge2022, icaloflow can realize the potential of normalizing flows in performing fast, high-fidelity simulation on detector geometries that are $\sim 10–100$ times higher granularity than previously considered.

We often encounter a situation where linear wave equations around a black hole solution can be regarded as continuous deformations of simpler ones, or modifications from the general relativity case by continuous parameters. We develop a general framework to compute high-order perturbative corrections to quasinormal mode frequencies in such deformed problems. Our method has many applications, and it allows us to compute numerical values of the high-order corrections very accurately. For several examples, we perform this computation explicitly and discuss analytic properties of the quasinormal mode frequencies for deformation parameters.

This work analyzes the asymptotic behaviors of the asymptotically flat solutions of Einstein-æther theory in the linear case. The vacuum solutions for the tensor, vector, and scalar modes are first obtained, written as sums of various multipolar moments. The suitable coordinate transformations are then determined, and the so-called pseudo-Newman-Unti coordinate systems are constructed for all radiative modes. In these coordinates, it is easy to identify the asymptotic symmetries. It turns out that all three kinds of modes possess the familiar Bondi-Metzner-Sachs symmetries or the extensions as in general relativity. Moreover, there also exist the subleading asymptotic symmetries parametrized by a time-independent vector field on a unit two-sphere. The memory effects are also identified. The tensor gravitational wave also excites similar displacement, spin, and center-of-mass memories to those in general relativity. New memory effects due to the vector and scalar modes exist. The subleading asymptotic symmetry is related to the (leading) vector displacement memory effect, which can be viewed as a linear combination of the electric-type and magnetic-type memory effects. However, the scalar memory effect seems to have nothing to do with the asymptotic symmetries at least in the linearized theory.

Nonlinear differential equations are derived that describe the time evolution of the test particle coordinates during finite motions in the gravitational field of oscillating dark matter. It is shown that in the weak field approximation, the radial oscillations of a test particle and oscillations in orbital motion are described by the Hill equation and the nonhomogeneous Hill equation, respectively. In the case of scalar dark matter with a logarithmic self-interaction, these equations are integrated numerically, and the solutions are compared with the corresponding solutions of the original nonlinear system to identify possible resonance effects.

We study the formation and evolution of solitons supported by repulsive self-interactions inside extended halos, for scalar-field dark matter scenarios. We focus on the semiclassical regime where the quantum pressure is typically much smaller than the self-interactions. We present numerical simulations, with initial conditions where the halo is described by the WKB approximation for its eigenfunction coefficients. We find that when the size of the system is of the order of the Jeans length associated with the self-interactions, a central soliton quickly forms and makes about 50% of the total mass. However, if the halo is 10 times greater than this self-interaction scale, a soliton only quickly forms in cuspy halos where the central density is large enough to trigger the self-interactions. If the halo has a flat core, it takes a longer time for a soliton to appear, after small random fluctuations on the de Broglie wavelength size build up to reach a large enough density. In some cases, we observe the coexistence of several narrow density spikes inside the larger self-interaction-supported soliton. All solitons appear robust and slowly grow, unless they already make up 40% of the total mass. We develop a kinetic theory, valid for an inhomogeneous background, to estimate the soliton growth rate for low masses. It explains the fast falloff of the growth rate as resonances between the ground state and halo excited states disappear. Our results suggest that cosmological halos would show a large scatter for their soliton mass, depending on their assembly history.