Papers

Despite its elusive character, coherent elastic neutrino-nucleus scattering (CEvNS) detection is evolving as a precision measurement from different neutrino measurements. In this note we show how CEvNS experiments using the Spallation Neutron Source (SNS) are robust measurements that enter into a precision era. Despite the interplay of nuclear and elementary particle physics, we demonstrate that CEvNS current measurements are accurately described by using only one extra parameter, the number of neutrons, $N$. By making this test, we illustrate that current CEvNS are precise enough to reconstruct the number of neutrons in the nuclear target. At the same time, determining the number of nucleons in the target material can be used as a benchmark for the precision and accuracy of this kind of detectors.

We present the first performance-portable implementation of a loop integral library for high-energy particle physics. The new code is based on the QCDLoop package, which provides an essential component in the software stack for perturbative precision calculations at collider experiments. Our implementation extends QCDLoop to modern computing architectures by means of the Kokkos portability framework, which allows to target most existing CPUs and GPUs.

We study the sensitivity of future high-luminosity $e^+e^-$ colliders to the electromagnetic and weak dipole moments of the $\tau$ lepton within the Standard Model Effective Field Theory. We analyse several complementary processes across the FCC-ee operating stages and show that the exceptional luminosity and clean environment of future $e^+e^-$ colliders allow for substantial improvements over current limits from LEP and the LHC. The $e^+e^- \to \tau^+\tau^-$ process provides excellent sensitivity to weak dipole operators through resonant $Z$ production and $Z$-pole energy scans, while $\gamma\gamma \to \tau^+\tau^-$ yields the strongest constraint on the anomalous magnetic moment owing to the dominance of linear interference effects in the near-threshold region. Higher-energy stages improve the sensitivity to the $\tau$ electric dipole moment. The radiative processes $e^+e^- \to \tau^+\tau^-\gamma$ and $H\to\tau^+\tau^-\gamma$ provide complementary, though subleading, probes of $\tau$ dipole operators. Combining all channels, we estimate the statistical reach at the 95% CL to be $|\Delta a_\tau|<2.8\times10^{-5}$, $|d_\tau|<2.5\times10^{-18}\,e\,{\rm cm}$, $|\Delta a_\tau^Z|<1.0\times10^{-5}$, and $|d_\tau^Z|<4.4\times10^{-19}\,e\,{\rm cm}$, improving upon the current bounds by several orders of magnitude. These projections quantify the potential statistical reach of the FCC-ee program, motivating dedicated studies incorporating detector effects, systematic uncertainties, and higher-order theoretical predictions.

The newly measured correlation between the neutrino and X-ray luminosities of Seyfert galaxies has yielded the first neutrino-based measurement of the Hubble constant. Building on this result, we forecast the reach of a global neutrino-telescope network by 2030, utilizing full-sky IceCube exposures combined with KM3NeT-ARCA and Baikal-GVD. We find that this 2030 configuration sharpens the neutrino-measured Hubble constant from today's $H_0 = 66^{+44}_{-37}$ to $H_0 =66^{+15}_{-13}$ km s$^{-1}$ Mpc$^{-1}$. Additionally, we project that the disk-corona slope of the neutrino X-ray luminosity relation ($L_\nu\propto L_X^\beta$) will reach $\beta=0.72\pm0.04$, enabling a $\geq \!5\sigma$ exclusion of the calorimetric value $\beta=1$. Finally, we show that, if a high-redshift population of neutrino sources, such as JWST's "little red dots," is identified and obeys the same luminosity relation, we can obtain a new independent measurement of the matter density $\Omega_m$ and the dark energy equation-of-state parameter $w$.

Ultralight dark photons (DPs) are well-motivated dark matter candidates. A promising yet underexplored mechanism for their relic abundance is parametric resonance in the Abelian-Higgs model that generates the DP mass. We advance previous analytical studies through dedicated 3D lattice simulations that capture important nonlinear effects, including backreaction and relic partitioning between the dark Higgs and DPs. We further predict the associated stochastic gravitational-wave (GW) signal, which can be within reach of a broad range of detectors, opening a new avenue to probe ultralight DP dark matter.

We argue that no material can be made completely transparent to light as long as it has a nontrivial index of refraction. The quantum decay of photons into phonons is an ineliminable source of attenuation. This survives even once all other excitations have been gapped away, impurities have been removed, and the temperature has been set to zero. Restricting for simplicity to the case of a superfluid, we determine via effective field theory methods the corresponding low-frequency contribution to the imaginary part of the index of refraction. This scales as $\omega^4$ and induces a nonanalyticity of the real part for $\omega \rightarrow 0$. We also extend our result to large coherent electromagnetic fields, such as those of a laser, showing that the effect can receive strong nonlinear enhancements. Our result is a genuine quantum lower bound to the transparency of a medium.

We compare three definitions of $\Xi_c$–$\Xi_c'$ mixing within a constituent-quark model: a spin-component probability angle, a common-source overlap angle, and an SU(3)-breaking mass-operator angle. The probability angle is $3.11^\circ$, while the two operator-based definitions give $2.48$–$2.58^\circ$; a second parameter set gives $2.38$–$2.49^\circ$. The operator-based angles are closer to the lattice determinations $1.2(1)^\circ$ and $0.810(50)(200)^\circ$, but remain larger. We then couple conventional $qsQ$ states to virtual $qsQg$ configurations, where $q=u,d$ and $Q=c,b$. An orbital-$S$-wave chromomagnetic transition containing both $j_{Qg}=1/2$ and $3/2$ raises the source and mass-operator charm angles to $2.67$–$3.16^\circ$ when normalized to reference short-range mass shifts. The hybrid probability stays below $1.7\%$, and the corresponding bottom angles are $0.42$–$0.48^\circ$. Eliminating the hybrid sector gives a rank-one mass correction precisely when all weighted transitions select the same retained-state combination. The mode-resolved calculation separates the flavor-breaking response that changes the mixing angle from the response that generates a second transition direction. The accompanying effective-current relation connects this mass analysis to radiative and semileptonic amplitudes through their current matrix elements.

The recently observed dark matter (DM) nuclear recoil event at an energy of $248 \pm 23\,(\text{stat.}) \pm 23\,(\text{syst.})\,\text{keV}$ at the LUX-ZEPLIN (LZ) experiment, favoring an inelastic scattering interpretation, has motivated various beyond the Standard Model (BSM) scenarios aimed at explaining the observed excess. In particular, this provides an opportunity to probe models that naturally accommodate inelastic DM scattering. In this work, we explore one such possibility by extending the $\rm U(1)_{L_{\mu}-L_{\tau}}$ model with two complex scalar fields, $\Phi$ and $S$, carrying charges $-1$ and $+2$, respectively, under the $\rm U(1)_{L_{\mu}-L_{\tau}}$ gauge symmetry. These charge assignments allow a trilinear interaction between the two scalar fields, which is crucial for generating the DM mass splitting. Following the spontaneous breaking of the $\rm U(1)_{L_{\mu}-L_{\tau}}$ symmetry, with $S$ acquiring a vacuum expectation value and generating a mass for the BSM gauge boson $Z_{\mu\tau}$, the real and imaginary components of $\Phi$ acquire a mass splitting. This naturally gives rise to an inelastic DM scattering scenario that can accommodate the LZ excess. We perform a likelihood-based assessment of the sensitivity of the model parameters to the observed event while consistently accounting for other relevant phenomenological constraints. Finally, we discuss the prospects for probing the viable parameter space at future experiments.

Gravitational waves from vacuum first-order phase transitions probe the nonlinear dynamics of relativistic bubble collisions. Predicting their spectrum requires resolving Lorentz-contracted scalar bubble walls throughout a volume containing many bubbles, making the large-boost regime prohibitively expensive for direct lattice simulations. We develop a simulation-based pairwise surrogate that separates the microscopic collision dynamics from the geometry of the multi-bubble transition. This utilizes symmetry-reduced $(1+1)$-dimensional scalar-field simulations to build a library of two-bubble gravitational-wave spectra, including the nonlinear post-collision evolution. These spectra are combined with geometric weights that account for screening by other bubbles. We test the two-bubble spectra and the reconstructed spectra of three- and many-bubble systems against full $(3+1)$-dimensional lattice simulations. Not only can the surrogate be orders of magnitude cheaper computationally, but it also provides access to highly relativistic collisions beyond the practical reach of direct many-bubble simulations. This provides a route to studying how the spectral amplitude and shape depend on the collision boost and scalar potential.

We study how charged-lepton flavour violation (CLFV) generated in the $\tau$ sector propagates into the $\mu\to e$ sector within the Standard Model Effective Field Theory (SMEFT). Assuming that new physics at a scale $\Lambda\gg v$ produces only dimension-6 operators that mediate $\tau\to e$ and $\tau\to\mu$ transitions, we identify and compare the three mechanisms that induce $\mu\to e$ observables. All three originate from double insertions of the two $\tau\to\ell$ operators and scale as $C_6^{\tau e}C_6^{\tau\mu}/\Lambda^4$. (T1) Renormalization-group mixing misaligns the charged-lepton mass matrix, and the rotation to the mass basis generates dimension-6 $\mu\to e$ operators. (T2) A finite, non-logarithmic remainder, which we find to be negligible. (T3) The overall divergence renormalizes dimension-8 operators, contributing after electroweak symmetry breaking. Since T1 and T3 carry no relative power of $\Lambda$, neither can be neglected at any scale, and only their comparison reveals which mechanism, and hence which $\mu\to e$ observable, most strongly probes a given operator pair. Surveying the Warsaw-basis operators, we classify representative $(\tau\to e,\tau\to\mu)$ pairs into T1-dominated, T3-dominated, and T1–T3-comparable regimes, and explain the hierarchy through the underlying mixing chains. Translating current $\mu\to e\gamma$, $\mu\to eee$ and $\mu\to e$ conversion limits into bounds on products of $\tau\to\ell$ Wilson coefficients, we find that they exceed the direct $\tau$-decay constraints by factors of ten to several hundred. Excluding either T1 or T3 would miss these limits by orders of magnitude for some pairs, and shift them by factors of two to three in others. Interpreting $\mu\to e$ data as a probe of $\tau$ flavour violation therefore requires both the dimension-6 RG running and the dimension-8 mixing contributions.

In this paper, we study the nature of wave packets and their decay behavior in the $\kappa$-Minkowski space. We employ techniques from singularity theory throughout our analysis. Specifically, we use methods from the theory of Lagrangian singularities and caustics to study the topology of the energy-level manifold. The Newton polyhedron method from the theory of oscillatory integrals is applied to analyze the decay behavior of wave packets. We find that for a generic Hamiltonian in the $\kappa$-Minkowski space, the associated wave packets exhibit different decay rates depending on the control parameter of the system. When the control parameter takes values on the cusp, the system exhibits decay of order $t^{-1/4}$; otherwise, it exhibits decay of order $t^{-1/2}$. This distinctive behavior of wave packets in the $\kappa$-Minkowski makes it fundamentally different from commutative spacetime.

Machine learning (ML) in high-energy nuclear physics (HENP) is entering a new stage in which physical knowledge is incorporated more directly into data analysis, simulation, and physics inference. This mini-review focuses on developments that have matured in the past several years. Whereas earlier applications emphasized event classification, pattern recognition, and surrogate models for selected observables, recent work has moved toward physics-integrated workflows: calibrated Bayesian extraction of QCD matter properties, dense-matter equation-of-state inference from heavy-ion and neutron-star data, generative event modeling, neural unfolding of weak physical signals, differentiable inverse solvers, gauge-equivariant and diffusion-based lattice-field samplers, and neural reconstruction of model functions in holographic QCD. We survey recent applications of ML in heavy-ion collisions, neutron-star physics, lattice QFT, and holographic or continuum QCD. The emphasis is not on ML architectures alone, but on how they enter concrete physics workflows, how physical constraints such as symmetries, conservation laws, causality, thermodynamic stability, and topology are imposed, and how uncertainty quantification and validation determine whether an AI-assisted result can support a reliable physics conclusion.

We calculate the dominant bosonic two-loop virtual electroweak corrections to parity-violating Møller scattering at low energies. The electron effective weak charge is extracted from the polarization asymmetry, retaining all contributions that are enhanced by $(1-4\sin^2\theta_W)^{-1}$ or $\ln^2(M_{W,Z}^2/Q^2)$ relative to the tree-level contribution. Analytical results are obtained using the expansion by regions method in the low-energy limit $Q^2\ll M_{W,Z}^2$. Within this approximation, the dominant two-loop bosonic corrections shift the electron effective weak charge (or equivalently the polarization asymmetry) by $0.3\%$. We examine the origin of the leading contributions to this result and assess the remaining theoretical uncertainty from purely bosonic contributions for the MOLLER experiment to about 0.1%.

We quantify the impact of higher-dimensional operators in the effective theory for bubble nucleation, focusing on supercooled phase transitions in the classically conformal Abelian-Higgs model. While high-temperature dimensional reduction organizes hard thermal corrections into a tower of operators in a three-dimensional effective field theory, recent results show that dimension-six terms can dominate over higher-loop corrections to the equilibrium thermodynamics of the strongest transitions. To assess their effect on the nucleation rate and the derived near-equilibrium phase-transition observables, we develop a perturbative framework that includes them in the full one-loop nucleation rate. Including higher-dimensional operators both in the bounce action and in the fluctuation determinants, we solve the resulting Sturm-Liouville problem without a derivative expansion, using a modified Gel'fand-Yaglom method. For strongly supercooled transitions, we find that higher-dimensional operators only marginally affect the nucleation rate and the resulting observables. As a byproduct, we delineate the regime of validity of the high-temperature nucleation effective theory in supercooled phase transitions.

Non-Abelian gauge theories above four dimensions may admit an interacting ultraviolet fixed point through the competition between canonical scaling and gauge-field antiscreening. Using the four-loop $\overline{\mathrm{MS}}$ beta function continued to $D=4+2\epsilon$, we determine the largest dimension $D_{\mathrm{pt}}=4+2\epsilon_{\mathrm{pt}}$ below which successive loop corrections to the fixed point remain hierarchically ordered under a specified ratio criterion, and map $D_{\mathrm{pt}}$ over color and flavor numbers for fermions in the fundamental representation of $SU(N)$. At $D=5$, we construct rational anomalous dimensions with a fixed, pole-regularized denominator inspired by the functional renormalization group (fRG). Matching to the $\overline{\mathrm{MS}}$ series through one, two, and three loops produces progressively smaller shifts in the critical flavor number and coupling at the ultraviolet–infrared merger (the point where the infrared and ultraviolet fixed points coincide), yielding $N_f^{\mathrm{cr}}\simeq 2.09 \, N$ at large $N$ in the three-loop construction. This low-order stabilization, together with qualitative evidence from fRG flows including higher gauge operators, suggests a potential merger scenario that bounds the candidate asymptotically safe region in flavor number. The resulting color–flavor map provides guidance for five-dimensional model building by displaying both the baseline perturbative-control boundary and the candidate three-loop merger boundary. Four-loop matching, however, retains an interacting ultraviolet fixed point beyond the three-loop merger boundary, with no merger found for integer $2\le N\le15$ and $0\le N_f/N\le11/2$. The sensitivity of the fixed-point structure to higher-order terms leaves both scenarios open, highlighting fixed-point annihilation as a potential constraint on five-dimensional asymptotic safety.

Hyperon polarization in relativistic heavy-ion collisions sensitively probes thermal vorticity and the operator structure of local equilibrium. We investigate an isotropic generalized uncertainty principle (GUP) via a spin-independent scalar deformation of the one-particle phase-space density of states in the local rest frame (LRF). We employ the Belinfante-Rosenfeld local-equilibrium operator, the standard on-shell dispersion relation, and the Pauli-Lubanski/axial-Wigner representation of the spin-$1/2$ observable, retaining terms linear in the GUP coefficient and in hydrodynamic gradients. The same scalar GUP factor appears in the scalar and axial phase-space contributions and cancels from the local mean-spin ratio at fixed spacetime point and momentum. Thus, the leading GUP contribution to an experimentally relevant polarization observable arises through the Cooper-Frye freeze-out integrals and can be expressed as a covariance between the LRF momentum invariant and the local spin kernel. This cancellation is a consequence of the scalar density-of-states modification within a fixed pseudogauge and does not imply pseudogauge independence of the polarization observable. For $\Lambda$ hyperons, a Maxwell-Boltzmann thermal estimate shows that the dependence on freeze-out temperature and fluid-dynamical correlations is substantially larger than the Fermi-Dirac correction, which remains negligible over the temperature range considered. Present LHC precision corresponds only to a formal linear sensitivity of order $10$-$30~\mathrm{GeV}^{-2}$. Since this interval lies beyond the domain in which the linear GUP expansion is reliable, no exclusion limit is inferred. Differential measurements of hyperon polarization as functions of momentum, rapidity, collision centrality, and azimuthal harmonic structure provide the most direct experimental avenue for testing the predicted covariance dependence.

We present an improved parametric model for neutrino emission from core-collapse supernovae that directly connects neutrino luminosity and average energy to stellar properties during emission. Our model incorporates two critical physical processes: convection within the proto-neutron star and the evolution of the neutrinosphere radius during the early emission phase. Using simulated datasets of supernova neutrino events in the Super-Kamiokande detector, we assess the sensitivity to astrophysical properties in the event of a future detection. We show that the neutrino mass ordering plays a crucial role in determining which parameters can be constrained by the observed neutrino data.

In this work, we theoretically investigate the non-equilibrium evolution of the correlation functions of a quantum scalar field following a mass quantum quench in a finite-size system. The self-consistent equation for the Keldysh (statistical) correlation function is solved numerically in the one-loop approximation. A specific spatio-temporal effect is observed: at a point in time approximately equal to half the system size, the effective mass experiences a strong disturbance. It is shown that this effect is driven by the interference of counter-propagating wave fronts of fluctuations that propagate within the light cone and is induced by periodic boundary conditions.

Motivated by the potential existence of a dark QCD sector, we construct a $SU(N)$ strongly coupled dark sector by extending the Standard Model (SM) gauge group to an enlarged $SU(N+5)\times SU(N+1)\times U(1)$, under which the dark quark candidates naturally arises from the same multiplets as the SM fermions. The dark QCD sector from the extension inherits the rich structure of the SM, featuring three distinct properties: (1) Mixed representations: There are dark quarks of three different representations, including fundamental ($\chi_f$), antisymmetric ($\chi_a$), and symmetric ($\chi_s$), which can be traced back to the chiral structure of the SM. (2) Flavor: Each representation features three generations, with their flavor structures and Yukawa interactions directly related to those of the SM. (3) Global symmetries: Alongside the conventional dark baryon number $D$, we identify an exotic dark baryon number $\widetilde{D}$ from a conserved $(B-L)-\widetilde{D}$ symmetry. These features provide novel perspectives on the structure of dark QCD sectors. Furthermore, the extension of the scalar and gauge sectors introduces various portals between the dark QCD sector and the SM sector. We systematically study these portals, including quark portal, lepton portal, Higgs and $Z$ portal, heavy $Z'$ portal, kinetic mixing portal, dipole portal, and dark pion/axion portals. With a concrete UV model, their origin become robust, providing additional guidance for experimental searches of the dark sector.

The BESIII Collaboration recently extracted the properties of the $X(2370)$ from a fit to the one-dimensional $K_S^0K_S^0\pi^0$ invariant-mass spectrum in $J/\psi\to\gamma K_S^0K_S^0\pi^0$. The intermediate two-body structures visible in the mass correlations, including the $K_0^*(1430)$ bands, require a coherent treatment of cross-channel interference when interpreting the enhancement near 2.3 GeV. We reassess the need for an additional $X(2370)$ contribution by fitting the published data using an effective coupled-channel framework. The three-body parent amplitude is parameterized by a $K$-matrix as the scattering among several quasi-two-body channels. The seven- and eight-bare-state models give similar mass distributions. Adding the eighth bare state lowers the Poisson deviance by 1.26% and produces an additional pole at $E=(2424-i\,149)$ MeV, substantially broader than the $X(2370)$ mass-width reference. This pole is model-dependent, and its identification with the $X(2370)$ is not clear. The present analysis does not establish the need for an additional $X(2370)$ contribution in $J/\psi\to\gamma K_S^0K_S^0\pi^0$, thereby weakening the flavor-singlet argument based on the suppression of $K^*\bar K$ relative to the total $K\bar K\pi$ contribution. A more comprehensive experimental amplitude analysis, incorporating coherent interference, mass and angular correlations, and detector effects across related decay channels, is needed to establish the role and decay properties of the $X(2370)$.

As part of a PhD thesis entitled `Scalar perturbations in warm inflation and during reheating' we present a software for computing warm inflation observables. In particular, our Mathematica implementation computes the power spectrum, spectral tilt, and tensor-to-scalar ratio for a given momentum scale. Compared with other implementations, we start in a Bunch-Davies state deep inside the horizon, ideally at a time when thermal noise is exponentially suppressed. We integrate gauge-invariant equations for three curvature perturbations across horizon exit. We continue deep enough outside of horizon so that all curvature perturbations agree. Results are illustrated for Standard Model embedded warm inflation, and we also provide notebooks for several other popular potentials and friction coefficients. The theoretical foundations for the code can be found in the main part of the thesis or in earlier papers [1,2]. Specifically, part II derives gauge-invariant, model-agnostic evolution equations, as well as the noise autocorrelator interpolating between quantum and classical domains. Part III presents the general ideas behind the numerical implementation, while part IV presents selected results. The code is described, line-by-line, in Appendix A. The published PhD thesis is available at https://doi.org/10.48620/101166 while the notebooks can be downloaded from https://github.com/alicarogeljblackhole/Warm-Inflation.

One of the challenging components of modern lattice-QCD computations of the leading hadronic vacuum polarization contribution to the muon $(g-2)_\mu$ is the isospin-breaking correction due to electromagnetism. Dominated by long distances, this correction suffers from severe signal-to-noise issues and finite-volume effects. To provide infinite-volume benchmarks for various quark-level Wick contractions, we estimate their sizes phenomenologically at the physical point, using a previously developed vector-meson-dominance model. The pion contributions in this model sum to around $-7.1\times 10^{-10}$, dominated by the electromagnetic pion mass shift. The ultraviolet-finite (2+2)a ("dumbbell") contraction accounts for approximately two thirds of this model sum; for both, about 30% comes from Euclidean times beyond 2.8 fm.

Searches for Charged Lepton Flavor Violation (CLFV) are powerful tools to probe physics beyond the Standard Model (BSM). This chapter provides a comprehensive survey of CLFV theory, focusing primarily on low-energy muon and tau transitions while outlining complementary searches from high-energy colliders. Grounded in the Effective Field Theory (EFT) framework, we systematically review key observables including radiative and purely leptonic decays of muon and tau as well as $\mu\to e$ conversion in nuclei and $\tau$ hadronic decay channels. CLFV involving light new physics particles is also discussed. This review captures the modern synergy between EFTs, novel light-mediator scenarios, and hadronic and nuclear physics in the ongoing hunt for BSM signals.

Motivated by the recent JUNO indication favoring normal neutrino mass ordering, we study two realizations of the minimally modified Frampton–Glashow–Yanagida (MMFGY) framework in the minimal type-I seesaw with two right-handed neutrinos. Both retain one exact Yukawa texture zero, supplemented by either a single physical CP-violating phase or a remnant CP symmetry. The explicit-CP realization yields twelve high-energy Yukawa configurations that reduce to three low-energy classes, with correlated CP phases and predictions for neutrinoless double-beta decay. In both realizations, a strongly suppressed second Yukawa entry can emerge, although the full-matrix hierarchy remains moderate in the quasi-degenerate regime. We analyze leptogenesis for a non-degenerate benchmark, quasi-degenerate TeV-scale right-handed neutrinos, and lower masses where coherent production, oscillations, and electroweak sphaleron freeze-out become important. Successful leptogenesis is obtained across a broad range of the scanned benchmarks, with increased sensitivity to the initial right-handed-neutrino abundance at the lowest mass scale. Requiring successful leptogenesis restricts the allowed phases while preserving the possibility of an approximate second zero. The two realizations exhibit distinct approximate-zero patterns and leptogenesis predictions, demonstrating how different restrictions on the high-energy Yukawa structure affect baryogenesis.

We compute the chiral-odd form factors $H_T$, $E_T$ and $\hT$ of the nucleon in light-cone QCD sum rules, separately for the $u$ and $d$ quarks, and organise them into the tensor monopole, dipole and quadrupole moments $g_T$, $\kappa_T$ and $Q_T$. The quadrupole moment, with no chiral-even counterpart at leading twist, and the isoscalar channel, whose sum rules were derived but never evaluated, are new in this framework. The form factors are read from a Lorentz basis independent only after canonical ordering of the Dirac strings; three of the eight surviving structures give the three form factors separately, and the one usually used for the tensor charge is not among the eight. Two exact results follow analytically. The $d$-quark contributions to $E_T$ and $\hT$ are equal and opposite in the chiral limit, broken in proportion to the quark mass and the twist-six amplitude $\mathcal{V}_6$, so the $d$-quark sector carries a single independent function; and the isoscalar tensor charge receives no leading-twist contribution, its twist-three terms cancelling between the flavours. Neither is visible without resolving the flavours. At $\mu^2=1$~GeV$^2$ the two distribution-amplitude sets give $g_T^{u-d}=1.27(7)$, $1.08(6)$, $\kappa_T^{u-d}=1.35(62)$, $1.58(59)$, $Q_T^{u-d}=-4.40(83)$, $-4.20(73)$ and $g_T^{u+d}=0.39(7)$, $0.38(6)$, $\kappa_T^{u+d}=4.47(62)$, $4.32(59)$, $Q_T^{u+d}=2.41(53)$, $1.56(30)$. The mean-field relation $2\hT^{u-d}=-E_T^{u-d}$, tested without any large-$N_c$ assumption, holds in sign and order of magnitude, with ratio $0.64(16)$ and $0.67(15)$ against the predicted unity. In the impact-parameter plane the moments displace the two flavour distributions in opposite transverse directions by nearly equal amounts, $\langle b_y\rangle=0.37$ and $-0.37$~fm, and elongate both across the polarisation axis, the $d$ quark some five to six times more strongly

The proximity of the narrow $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ structures to the $\Sigma_c\bar D^{(*)}$ thresholds motivates their interpretation as hadronic molecules. We treat the $P_c(4312)$ as an $S$-wave $\Sigma_c\bar D$ state with $J^P=1/2^-$ and examine both $J^P=1/2^-$ and $3/2^-$ $\Sigma_c\bar D^*$ assignments for each heavier peak. The selected $S$-wave open-charm transitions to $\Lambda_c\bar D^{(*)}$ are calculated at Born order in the quark-interchange model, including the prior and post rearrangement diagrams and their color, flavor, spin, and spatial matrix elements. Across the input variations considered, the quark-interchange widths robustly favor $\Lambda_c\bar D^*$ over $\Lambda_c\bar D$ for every $J^P=1/2^-$ assignment. At either heavier peak mass, the $\Lambda_c\bar D^*$ width for $J^P=3/2^-$ is suppressed by approximately one order of magnitude relative to $J^P=1/2^-$, providing a potential decay-based discriminator of the spin assignments. The large channel hierarchies arise from spatial overlaps and interference between spin-independent and hyperfine contributions and are not universal heavy-quark-spin-symmetry ratios. We also explore a retarded one-pion-exchange transition at first Born order. It affects $P_c(4312)\to\Lambda_c\bar D^*$ most strongly, while the coherent widths remain sensitive to the cutoff, energy-transfer prescription, short-distance subtraction, and unresolved relative matching sign. The quark-interchange hierarchies are therefore the central predictions, whereas the pion-exchange results quantify matching sensitivity. Measurements of the $\Lambda_c\bar D^*$ modes can directly test these patterns.

We present a non-perturbative formulation of quantum gravity in asymptotically flat spacetimes using Witten's cubic open string field theory (OSFT) on unstable D-branes. Given that the massless spin-2 sector of the closed string spectrum inherently encodes the degrees of freedom of quantum gravity, we establish this connection by mapping on-shell closed string excitations directly to gauge-invariant operators in OSFT, realizing a concrete flat-space analogue of the AdS/CFT correspondence. By evaluating the OSFT correlation functions of these operators perturbatively around the tachyon vacuum, we systematically reproduce the all-orders genus expansion of the closed string S-matrix for the associated states. This demonstrates that closed string theory-and thus quantum gravity-emerges dynamically from the open string tachyon vacuum, establishing Witten's OSFT as a fully calculable, non-perturbative framework for flat-space quantum gravity.

The cooling of neutron stars (NSs) provides insight into their composition and equation of state. However, a complete understanding of this phenomenon is still an open question. The early stage of NS cooling is dominated by neutrino emission from the core, which rapidly cools the star. Urca processes are one such mechanism where neutrinos escape from the core, carrying away most of the heat. Nucleonic and hyperonic direct Urca processes are known rapid cooling mechanisms. The possible appearance of $\Delta$ baryons in dense matter introduces additional weak-interaction channels, including $\Delta$ direct Urca processes. Although such processes have been discussed in the context of $\Delta$-admixed NS matter, their neutrino emissivities and impact on NS cooling have not been systematically investigated. In this work, for the first time we incorporate the neutrino emissivities of the relevant $\Delta$ direct Urca processes into NS cooling simulations. We investigate the thermal evolution of $\Delta$-admixed NSs and assess the impact of these additional neutrino emission channels on their cooling behavior. We find that $\Delta$ direct Urca processes can provide an efficient neutrino-cooling mechanism and significantly accelerate the thermal evolution of NSs. Our results demonstrate that $\Delta$ baryons and their associated weak-interaction processes can play an important role in explaining NSs with unusually low surface temperatures and provide a new connection between the composition of dense matter and NS cooling observations.

We study photon conversion into light particles, such as dilatons, axions, and gravitons, induced by background magnetic fields, and formulate the resulting evolution in terms of the Stokes parameters. We show that photon conversion reduces to an effective non-unitary evolution of the photon sector. In the perturbative regime, the Hermitian and anti-Hermitian parts of the effective photon Hamiltonian are related through Kramers–Kronig relations, revealing that the changes in the Stokes parameters are not independent. We apply this general framework to photon evolution in Gaussian stochastic magnetic fields with possible helicity, and derive the ensemble-averaged evolution of the Stokes parameters. We find that two nonzero contributions arise even in the absence of magnetic helicity, which respectively correspond to the overall attenuation of all the Stokes parameters and to an irrelevant overall phase. We also find that magnetic helicity gives rise to two additional contributions, one of which changes the circular polarization while the other induces a rotation of linear polarization. These contributions form two Kramers–Kronig pairs. In particular, photon conversion induced by magnetic helicity is accompanied by both circular-polarization and birefringent responses. The same structure appears in dilaton-photon, axion-photon, and graviton-photon systems, revealing universality of photon conversion in magnetic fields.

While both neutrino propagation in photons and ultrarelativistic plasmas and neutrino oscillations in curved spacetimes have been studied extensively, their combination in a self-gravitating geometry appears not to have been considered previously. In this paper, we will investigate neutrino oscillations inside a static spherically symmetric spacetime, derived self-consistently from Einstein's equations, supported by ultrarelativistic matter. By relying on the geodesic motion and geometrical symmetries of the configuration, we will compute analytically the neutrino eikonal and spinoptics phase oscillations. Next, we will relate resonance phenomena to the physical interpretation of the background material inside which neutrinos travel for disentangling gravitational versus electroweak effects. We will inspect the effects of the pure gravitational and pure matter fields, and of the temperature in the neutrino oscillations; we will explain why our results are not coordinate artifacts, and we will certify our heuristic method by comparing with the asymptotic behaviours predicted by thermal field theory approaches. We will raise awareness on the relevance of the spinoptics phase shift entering the flavor conversion probability, should the neutrinos hit a curvature singularity. Theoretically, we will scrutinize the separate roles of geometrical symmetries versus physical features of the configuration, while astrophysically we will qualitatively discuss neutrino oscillations inside stars and in the Cosmic Microwave Background at different temperature and density conditions. Our research puts forward, in the context of the Tolman VI metric, an observational method for identifying naked singularities in our Universe: neutrinos would simultaneously be physically overlapped, in flavor-equilibrium and quantum-mechanically scrambled.