We calculate the gluon gravitational form factors (GFFs) of the proton using a light-front spectator model based on soft-wall anti–de Sitter (AdS)/quantum chromodynamics (QCD), where the active parton is a gluon. The model parameters are determined by fitting the unpolarized gluon distribution function to the nnpdf3.0nlo dataset. Subsequently, we predict the polarized gluon distribution, finding consistency with global analyses. Our predictions for the gluon GFFs show good agreement with recent lattice QCD simulations and experimental extractions. Using these gluon GFFs, we compute the contribution of the gluon to the proton mass and mechanical radii. We also analyze the gluonic contribution to the two-dimensional Galilean densities, including energy density, radial and tangential pressure, isotropic pressure, and pressure anisotropy of the proton.

The chiral crossover of QCD at finite temperature and vanishing baryon density turns into a second-order phase transition if lighter than physical quark masses are considered. If this transition occurs sufficiently close to the physical point, its universal critical behavior would largely control the physics of the QCD phase transition. We quantify the size of this region in QCD using the functional renormalization group. This allows us to study both critical and noncritical effects on equal footing, facilitating a precise determination of the scaling regime. We find that the physical point is far away from the critical region. Importantly, we show that the physics of the chiral crossover is dominated by soft modes even far beyond the critical region. While scaling functions determine all thermodynamic properties of the system in the critical region, the order parameter potential is the relevant quantity away from it. We compute this potential in QCD using the functional renormalization group and Dyson-Schwinger equations and provide a simple parametrization for phenomenological applications.

We present analytical expressions for the transverse momentum dependent (unintegrated) gluon and quark densities in a proton derived at leading order of QCD running coupling and valid at both small and large $x$. The calculations are performed using the Kimber-Martin-Ryskin/Watt-Martin-Ryskin prescription (in both differential and integral formulations) with different treatment of kinematical constraint, which reflects the angular and strong ordering conditions for parton emissions. As an input, the analytical solution of QCD evolution equations for conventional (collinear) parton distributions is applied, where the valence and nonsinglet quark parts obey the Gross-Llewellyn-Smith and Gottfried sum rules, and momentum conservation for the singlet quark and gluon densities is taken into account. Several phenomenological parameters are extracted from the combined fit to precision data on the proton structure function $F_2(x,Q^2)$ collected by the BCDMS, H1, and ZEUS Collaborations, comprising a total of 933 points from 5 datasets. Comparison with the numerical results obtained by other groups is presented, and the phenomenological application to the inclusive $b$-jet production at the LHC is given.

A search for $CP$ violation in ${\mathrm{\Lambda }}_b^0\to p{K}^{-}$ and ${\mathrm{\Lambda }}_b^0\to p{\pi }^{-}$ decays is presented using the full Run 1 and Run 2 data samples of $pp$ collisions collected with the LHCb detector, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$ at center-of-mass energies of 7, 8, and 13 TeV. For the Run 2 data sample, the $CP$-violating asymmetries are measured to be $A_{CP}^{p{K}^{-}}=(-1.4\pm 0.7\pm 0.4)\%$ and $A_{CP}^{p{\pi }^{-}}=(0.4\pm 0.9\pm 0.4)\%$, where the first uncertainty is statistical and the second is systematic. Following significant improvements in the evaluation of systematic uncertainties compared to the previous LHCb measurement, the Run 1 dataset is reanalyzed to update the corresponding results. When combining the Run 2 and updated Run 1 measurements, the final results are found to be $A_{CP}^{p{K}^{-}}=(-1.1\pm 0.7\pm 0.4)\%$ and $A_{CP}^{p{\pi }^{-}}=(0.2\pm 0.8\pm 0.4)\%$, constituting the most precise measurements of these asymmetries to date.

In general the speed of gravitational waves (GWs) in scalar-tensor modifications of Einstein’s gravity is different from the speed of light. Nevertheless, it has been measured that their speeds are nearly the same. For the most general scalar-tensor theories classified to date that do propagate a graviton—DHOST, including Horndeski and beyond Horndeski (BH) theories—we show that, remarkably, up to five self-consistent couplings of the scalar of dark energy (DE) to the photon are enough to make their GWs luminal in a wide set of cases. We find at least one luminal BH theory for which the GW decay into DE is suppressed in any cosmological background.

We investigate the role of both magnetic field and chemical potential on the emergence of chaotic dynamics in the quantum chromodynamics (QCD) confining string from the holographic principle. An earlier developed bottom-up model of Einstein-Maxwell-dilaton gravity, which mimics QCD features quite well, is used. The qualitative information about the chaos is obtained using the Poincaré sections and Lyapunov exponents. We find signatures of chaos in energetically disfavored string configurations, that are closer to the horizon, whereas no chaos is observed in energetically favored string configurations that are away from the horizon. Our results depend quite strongly on the frame we consider in the analysis. In the string frame, the chemical potential and the magnetic field suppress the chaotic dynamics in both parallel and perpendicular orientations of the string with respect to the magnetic field. Meanwhile, in the Einstein frame, the magnetic field suppresses/enhances the chaotic dynamics when the string is orientated perpendicular/parallel to the magnetic field, while the chemical potential enhances the chaotic dynamics for both orientations. The reported Lyapunov exponents are consistent with a classical analogue of the Maldacena-Shenker-Stanford bound in the parameter space of the model and we find it to be always satisfied in both frames.

We develop a conformally invariant (CI) framework in ($1+3$)-dimensional de Sitter (dS) spacetime, that unifies the descriptions of graviton, partially massless graviton, and photon fields. This framework is grounded in a rigorous group-theoretical analysis in the Wigner sense and employs Dirac’s six-cone formalism. Originally introduced by Dirac, the concepts of conformal space and the six-cone formalism were used to derive the field equations for spinor and vector fields in ($1+3$)-dimensional Minkowski spacetime in a manifestly CI form. Our framework extends this approach to dS spacetime, unifying the treatment of massless and partially massless fields with integer spin $s>0$ under conformal symmetry. This unification enhances the understanding of fundamental aspects of gravitational theories in curved backgrounds.

Gravitational waveform (GW) models are a core ingredient for the analysis of compact binary mergers observed by current ground-based interferometers. We focus here on a specific class of such models known as phenomx, which has gained popularity in recent years thanks to its computational efficiency. We introduce a new description of the “twisting-up” mapping underpinning the construction of precessing waveforms within this family. The new description is an adaptation to the frequency domain of a technique previously implemented in time-domain models, where the orbit-averaged post-Newtonian spin-precession dynamics is numerically solved on the fly. We also present an improved version of the gravitational wave strain amplitudes approximating the signal in the coprecessing frame. We demonstrate that the new description yields improved matches against numerical relativity simulations, with only a modest computational overhead. We also show that the new model can be reliably employed in parameter estimation follow-ups of GW events, returning equivalent or more stringent measurements of the source properties compared to its predecessor.

The low energy effective theory of gravity consists of two elements of quantum theory joined to classical general relativity. The first is the quantum conformal anomaly, which is responsible for macroscopic correlations on light cones and a stress tensor that can strongly modify the classical geometry at black hole horizons. The second is the formulation of vacuum energy as ${\mathrm{\Lambda }}_{\mathrm{eff}}\propto F^2$ in terms of an exact 4-form Abelian gauge field strength $F=dA$. When $A$ is identified with the Chern-Simons 3-form of the Euler class, defined in terms of the spin connection, a $J·A$ interaction is generated by the conformal anomaly of massless fermions. Due to the extreme blueshifting of local frequencies in the near-horizon region of a black hole, the lightest fermions of the Standard Model can be treated as massless there, contributing to the anomaly and providing a 3-current source $J$ for the Maxwell equation $d*F=*J$. In this phase boundary region, torsion is activated, and $F$ can change rapidly. The Schwarzschild black hole horizon is thereby replaced by a surface, with a positive surface tension and $\mathbb{R}\otimes {\mathbb{S}}^2$ worldtube topology, separating regions of differing vacuum energy. The result is a gravitational vacuum condensate star, a cold, compact, horizonless object with a $p_V=-{\rho }_V$ zero entropy, nonsingular de Sitter interior and thin quantum phase boundary layer at the Schwarzschild radius $2GM/c^2$.

We calculate for the first time the third-order spectrum of gravitational waves sourced by the scalar field perturbations amplified during inflation using the in-in formalism and discuss the conditions for the third-order spectrum to be smaller than the second-order one. We find that the third-order spectrum increases faster than the second-order one as the amplification of the field perturbations increases, and thus, the third-order spectrum dominates for detectable gravitational waves, which indicates that the perturbation theory breakdowns.

Nonlinear cosmological fields like galaxy density and lensing convergence can be approximately related to Gaussian fields via analytic point transforms. The LogNormal (LN) transform has been widely used and is a simple example of a function that relates nonlinear fields to Gaussian fields. We consider more accurate general point-transformed Gaussian (GPTG) functions for such a mapping and apply them to convergence maps. We show that we can create maps that preserve the LN’s ability to exactly match any desired power spectrum but go beyond LN by significantly improving the accuracy of the probability distribution function (PDF). With the aid of symbolic regression, we find a remarkably accurate GPTG function for convergence maps: its higher-order moments, scattering wavelet transform, Minkowski functionals, and peak counts match those of $N$-body simulations to the statistical uncertainty expected from tomographic lensing maps of the Rubin LSST 10 years survey. Our five-parameter function performs 2 to $5\times$ better than the LogNormal in terms of accuracy of tested non-Gaussian summary statistics. Since baryonic feedback has a strong influence on very small scales, we restrict our study to scales larger than 7 arcmin. We demonstrate that the GPTG can robustly emulate variations in cosmological parameters due to the simplicity of the analytic transform. This opens up several possible applications, such as field-level inference, rapid covariance estimation, and other uses based on the generation of arbitrarily many maps with laptop-level computation capability.

We test nonperturbative gluon propagators recently studied in the literature, by computing the topological susceptibility, $\chi$, of the superconductive phases of quantum chromodynamics at high density. We formulate the problem within the high-density effective theory, and use the two-particle irreducible formalism to compute the effective potential of the dense phases. We focus on superconductive phases with two and three massless flavors. Within this formalism, we write a Dyson-Schwinger equation in the rainbow approximation for the anomalous part of the quark propagator in the superconductive phases, in which the nonperturbative gluon propagator plays its role. We complete the model by adding a $U(1{)}_A$-breaking term whose coupling is fixed perturbatively at large quark chemical potential. We then use the effective potential to compute $\chi$ in the superconductive phases. We finally discuss implications of the results for the axion mass in superdense phases of quantum chromodynamics.

We carry out a combined study of the isospin-violating decay $D_s^{*}\to D_s{\pi }^0$ and radiative decay $D_s^{*}\to D_s\gamma$ in an effective Lagrangian approach by taking into account the corrections from the one-loop transitions. By distinguishing the transition mechanisms of the long-distance interactions through the intermediate meson loops from the short-distance interactions through the $\eta -{\pi }^0$ mixing at the tree level, the isospin-violating decay $D_s^{*}\to D_s{\pi }^0$ can be well constrained. In our approach, the higher-order corrections to the isospin-violating effects can involve the intermediate $D^{(*)}$ and $K^{(*)}$ scatterings. We find that the contributions from the destructive interference of intermediate meson loops via $D^{(*)0}(c\overline{u})K^{(*)+}(u\overline{s})$ and $D^{(*)+}(c\overline{d})K^{(*)0}(d\overline{s})$ rescatterings are significant. Within the commonly accepted UV cutoff range, we obtain the partial decay width $\mathrm{\Gamma }[D_s^{*}\to D_s{\pi }^0]={9.92}_{-0.66}^{+0.76}\mathrm{eV}$. This approach allows us to describe the $D_s^{*}$ radiative decay in the same framework via the vector-meson-dominance model. We demonstrate that both the tree-level and one-loop transitions can be self-consistently determined if we adopt the experimental data for the branching ratio fraction of $D_s^{*}\to D_s{\pi }^0$ to $D_s^{*}\to D_s\gamma$. It then leads to a reliable estimate of the total decay width of $D_s^{*}$, i.e., ${\mathrm{\Gamma }}_{\text{total}}(D_s^{*+})=170_{-12}^{+13}\mathrm{eV}$.

We present the first lattice QCD calculation of the quark transverse spin-momentum correlation, i.e., the T-odd Boer-Mulders function of the pion, using large-momentum effective theory. The calculation is done at three lattice spacings $a=\{0.098,0.085,0.064\}\mathrm{fm}$ and pion masses $\sim 350\mathrm{MeV}$, with pion momenta up to 1.8 GeV. The matrix elements are renormalized in a state-of-the-art scheme and extrapolated to the continuum and infinite momentum limit. We have implemented the perturbative matching up to the next-to-next-to-leading order and carried out a renormalization-group resummation. Our results provide valuable input for phenomenological analyses of the Boer-Mulders single-spin asymmetry.

We present a lattice calculation of the $\eta$ and ${\eta }^{\prime }$ meson masses at the physical point and in the continuum limit, based on $N_f=2+1+1$ flavors of rooted staggered quarks. Our analysis includes gauge ensembles at the physical pion and kaon masses spread over six lattice spacings in the range [0.064–0.1315] fm. Our main results read $m_{\eta }=543.5(5.6)\mathrm{MeV}$ and $m_{{\eta }^{\prime }}=986(38)\mathrm{MeV}$, consistent with the experimental values. This is an important numerical test that supports the validity of the fourth root procedure used in the staggered quark formalism. This calculation was the first step toward extracting the pseudoscalar transition form factors of the $\eta$ and ${\eta }^{\prime }$ mesons that play a crucial role in the hadronic light-by-light contribution to the muon $g-2$.

Five-point functions and five-body wave functions play an important role in many areas of nuclear and particle physics, e.g., in $2\to 3$ scattering processes, in the five-gluon vertex, or in the study of pentaquarks. In this work we consider the permutation group $S_5$ to facilitate the description of such objects. We work out the multiplets transforming under irreducible representations of $S_5$ and provide compact formulas allowing one to cast the permutations of an object $f_{12345}$ into combinations with definite permutation symmetry. We also give the explicit expressions for the irreducible multiplet products. We consider several practical applications as examples: We arrange the four-momenta and Lorentz invariants of a five-point function into the multiplet structure, we work out the color tensors of the five-gluon vertex in the multiplet notation, and we discuss applications for five-body wave functions like those of pentaquarks.

With the neutrino experiments advancing toward high-precision measurements and greater emphasis on reducing systematic uncertainties, improving the single-pion production models, a major component of the hadronic activity observed in the neutrino oscillation experiments, into the Monte Carlo simulations is crucial. This work presents the predictions of the struck nucleon’s Fermi motion by analyzing the charged-current neutral pion production on carbon nucleus in $\mathrm{MINER}\nu \mathrm{A}$. A minimal variation of genie and nuwro based on their default models shows an improvement in the prediction of single ${\pi }^0$ production. The prediction describes the data more accurately in the higher-momentum tail; however, discrepancies between the predictions and data below the Fermi peak highlight the limitations in current nuclear models used in the Monte Carlo generators.

Using $7.93{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we present an analysis of the decay $D^0\to \eta {\pi }^{-}{e}^{+}{\nu }_e$. The branching fraction of the decay $D^0\to a_0(980{)}^{-}{e}^{+}{\nu }_e$ with $a_0(980{)}^{-}\to \eta {\pi }^{-}$ is measured to be $(0.86\pm 0.17_{\mathrm{stat}}\pm 0.05_{\mathrm{syst}})\times {10}^{-4}$. The decay dynamics of this process is studied with a single-pole parametrization of the hadronic form factor and the Flatté formula describing the $a_0(980)$ line shape in the differential decay rate. The product of the form factor $f_{+}^{a_0}(0)$ and the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cd}|$ is determined for the first time with the result $f_{+}^{a_0}(0)|V_{cd}|=0.126\pm 0.013_{\mathrm{stat}}\pm 0.003_{\mathrm{syst}}$.

In neutrino long-baseline experiments the energy of the incoming neutrino must be reconstructed from observations of the final state. We first discuss the problems that arise for energy conservation during the final-state interactions in a momentum-dependent potential. We then show, for the example of the Deep Underground Neutrino Experiment, that the presence of such a potential is necessarily connected with a large uncertainty in the reconstructed energy. This same uncertainty also affects the determination of energy- and four-momentum transfers in neutrino-nucleus reactions. We analyze the origins of these uncertainties using transport theory for the description of the evolution of the final state of the reaction. We show that the spectral functions of target nuclei play an essential role not only for the initial neutrino-nucleon interaction but also for the final state evolution.