Thu·Dec 25, 2025Thursday·December 25, 2025

1. 01*

   Neutrino Non-Standard Interactions from LLE-type R-parity Violation

   Fang Xu🇨🇳

   We study neutrino non-standard interactions (NSI) induced by the trilinear $LLE$ couplings in $R$-parity-violating supersymmetry in a split-family spectrum where third-generation sleptons can be comparatively light. We systematically classify the relevant coupling patterns, derive the corresponding effective interactions and NSI parameters, and confront the resulting parameter space with a broad set of experimental constraints. We find that percent-level NSI can be realized in selected channels, with the largest magnitudes reaching ${\epsilon }_{ee}\simeq 8\%$ and ${\epsilon }_{\mu \mu }\simeq 3.8\%$, while other entries are typically restricted to the sub-percent level (including ${\epsilon }_{\mu \tau }\simeq -0.3\%$ in the viable off-diagonal case). We also highlight the structural origin of the different constraint patterns between ${\tilde{\tau }}_R$- and ${\tilde{\tau }}_L$-mediated scenarios and comment on the relation to the Zee model.

   hep-phPRD(2026)·0 citations
2. 02*

   Assessing the role of threshold conditions in the determination of uncertainties in pole extractions using Padé approximants

   Balma Duch🇪🇸 · Pere Masjuan🇪🇸

   In this letter, we discuss the determination of the $f_0(500)$ resonance by analytic continuation through Padé approximants of the $\pi \pi$-scattering amplitude from the physical region to the pole in the complex energy plane. Using as input a class of admissible parametrizations of the scalar-isoscalar $\pi \pi$ partial wave and imposing now the correct threshold behavior of the partial amplitude, we improve on the determinations of pole positions obtained in Ref. [1], thus empowering the Padé method as a simple and precise tool for extracting resonance poles from amplitudes.

   hep-phEur.Phys.J.ST(2026)·1 citation
3. 03*

   Echoes of $R^3$ modification and Goldstone preheating in the CMB-BAO landscape

   Tanmoy Modak🇮🇳

   The $R^2$ and the single-field-like regime of $R^2$-Higgs inflation are disfavored by the observed high spectral index $n_s$ from the combined cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) measurements at the $\sim 2\sigma$ level. The addition of a dimension-six $R^3$ term in the action helps alleviate this tension. We show that the parameter space accounting for the observed high $n_s$ also induces rapid Goldstone and Higgs preheating. The preheating, especially from Goldstone modes, helps match the CMB and inflationary scales, which in turn supports the observed $n_s$.

   hep-phastro-ph.COgr-qcPLB(2026)·2 citations
4. 04*

   Generalized structure functions in semileptonic tau decays

   Daniel A. López Aguilar🇲🇽 · Antonio Rodríguez Sánchez🇪🇸 · Pablo Roig🇲🇽 · Hanchen Yu🇪🇸

   In case there are tensor interactions beyond the SM in the low-energy effective Lagrangian, their interference with the SM V-A currents yields a contribution for tau decays into three or more mesons that cannot be included in the famous structure functions introduced by Kühn and Mirkes in their seminal 1992 paper. We present this generalization here, highlighting again the importance of measuring the (generalized) spectral functions, as being model-independent and exploiting maximally the data. This can be particularly relevant for CP and T violation studies with at least three mesons in the final state of the tau decay.

   hep-ph2 citations
5. 05*

   Irreducible Constraints on Hadronically Interacting Sub-GeV Dark Matter

   Peter Cox🇦🇺 · Matthew J. Dolan🇦🇺 · Avirup Ghosh🇦🇺

   We derive conservative upper limits on the dark-matter--nucleon scattering cross-section for sub-GeV mass dark matter. Working exclusively within the low-energy chiral effective theory, we derive bounds that are independent of the details of the dark matter interactions in the UV. Dark matter that interacts only hadronically at leading order also inevitably interacts with photons or electrons at next-to-leading-order. We show that these electromagnetic interactions lead to strong constraints from big bang nucleosynthesis and over-production of dark matter via freeze-in at low temperatures, while the leading-order hadronic couplings face stringent constraints from meson decays. Combining these constraints, we rule out both spin-independent and spin-dependent dark-matter--nucleon scattering cross-sections $\gtrsim 10^{-36}{\mathrm{cm}}^2$ for dark matter masses in the keV - 100 MeV range. These bounds are several orders of magnitude stronger than the existing constraints from astrophysics and cosmology and have significant implications for future low-mass direct detection experiments.

   hep-ph4 citations
6. 06*

   Connected and disconnected contributions to nucleon form factors and parton distributions

   Zaki Panjsheeri🇺🇸 · Saraswati Pandey🇺🇸 · Brannon Semp🇺🇸 · Simonetta Liuti🇺🇸

   Using the framework of generalized parton distribution, we provide a unified interpretation of the connected and disconnected contributions from the ab-initio Euclidean path-integral formulation of the hadronic tensor in both the nucleon elastic form factors and the parton distribution functions. We develop a phenomenology to elucidate non-perturbative contributions to deep inelastic structure functions, which can be extended to observables in heavy-ion collisions probing baryon junctions.

   hep-phhep-latnucl-ex0 citations
7. 07*

   Formulation of Relativistic Dissipative Spin Hydrodynamics

   Asaad Daher🇵🇱

   The primary objective of this thesis is to develop a consistent theoretical framework of dissipative hydrodynamics for a relativistic fluid with spin - hereafter referred to as relativistic dissipative spin hydrodynamics. In this framework, the dynamical description of a relativistic fluid requires a new macroscopic variable, the spin density, which is associated with a spin tensor. This tensor, defined as the expectation value of a rank-3 tensor operator in quantum field theory, contributes to the system's total angular momentum. The need for such a theory is motivated by recent measurements of spin polarization of hadrons produced in non-central relativistic heavy-ion collisions. Two distinct formulation methods are employed. The first is grounded in covariant thermodynamics and extends the conventional Navier-Stokes and Müller-Israel-Stewart theories of relativistic hydrodynamics by incorporating a spin tensor. The second is based on principles of relativistic quantum statistical mechanics, building upon and generalizing the foundational Zubarev approach. Both formulations aim to construct a closed system of evolution equations for the macroscopic variables and, via an entropy-current analysis, to identify the dissipative currents and their associated transport coefficients. These two approaches provide different perspectives for future applications focused on spin polarization measurements. Beyond its phenomenological relevance, the theory also opens several avenues for further theoretical developments. These include the verification of the thermodynamic relations employed in the first formulation method using microscopic frameworks, as well as a deeper understanding of the emerging transport coefficients - particularly those associated with the spin tensor - through microscopic modeling or data-driven parameter extraction.

   hep-phnucl-th0 citations
8. 08*

   Explicit rephasing transformation of four-generation mixing matrix and formulae for CP phases

   Masaki J. S. Yang🇯🇵

   In this letter, we present an explicit rephasing transformation that maps a general $4\times 4$ flavor mixing matrix to the standard parametrization of four-generation models. By combining rephasing-covariant minors and the determinant systematically, we derive expressions for all three Dirac-type CP phases, three Majorana phases, and four unphysical phases by arguments of matrix elements. The resulting formulae smoothly reduce to the three-generation results in the limit where the fourth generation decouples.

   hep-ph5 citations
9. 09*

   A novel realization of linear seesaw model in a non-invertible selection rule with the assistance of ${\mathbb{Z}}_3$ symmetry

   Hiroshi Okada🇨🇳 · Yutaro Shoji🇸🇮

   We propose a novel realization of linear seesaw model in a non-invertible selection rule with the assistance of ${\mathbb{Z}}_3$ symmetry. In our framework, Dirac mass matrices are generated at one-loop level, dynamically breaking the non-invertible symmetry while the symmetry is invariant under the tree-level. In addition to the active neutrino masses, the model exhibits rich and testable phenomenology such as non-unitarity bound, lepton flavor violations, lepton anomalous magnetic moment, and dark matter candidate. After describing our model, we carry out numerical analysis and show some results for our physical parameters.

   hep-phCPC(2026)·9 citations
10. 10*

    Axion-photon conversion in stochastic magnetic fields

    Wataru Chiba🇯🇵 · Ryusuke Jinno🇯🇵 · Kimihiro Nomura🇯🇵

    We investigate axion-photon conversion in stochastic magnetic fields, focusing on the evolution of the photon intensity and polarizations induced by conversion into axions. Assuming Gaussian magnetic fields characterized by the power spectra of their helical/non-helical components, we express the expectation values and variances of the photon intensity and linear/circular polarizations after conversion in terms of these spectra. We find nontrivial dependencies of these statistical quantities on the characteristic magnetic field correlation length, the propagation distance, and the axion mass. Moreover, we find that nontrivial polarizations emerge even if the photons are initially unpolarized, that the variances of these observables become suppressed in specific frequency regions, and that a peak structure arises in the expectation value of the circular polarization in the presence of statistically helical magnetic fields. We also point out consistency relations among these statistical quantities that hold independently of the specific forms of the magnetic field power spectra.

    hep-phastro-ph.COastro-ph.HEgr-qcPRD(2026)·1 citation
11. 11*

    HQET Spectroscopy of Radially Excited F-wave Mesons

    Palak Gupta🇮🇳 · Sapana Yadav🇮🇳 · Ritu Garg🇮🇳

    Motivated by the continuous advances in modern experimental facilities, we investigate the radially excited F-wave bottom and bottom-strange mesons that have not yet been observed experimentally. By combining theoretical inputs with available experimental information on charm mesons and applying flavor-symmetry parameters, we predict the masses of the radially excited F-wave bottom states and their strange partners. In addition, we compute their strong decay widths in terms of the hadronic coupling constants ${\tilde{g}}_{ZH}$ and ${\tilde{g}}_{RH}$. Using the presently estimated values of these couplings, we obtain upper bounds on the corresponding decay widths. These predictions will serve as testable benchmarks for forthcoming heavy-flavor spectroscopy findings.

    hep-phPTEP(2026)·0 citations
12. 12*

    Large lepton asymmetry from axion inflation and helium abundance hinted by ACT

    Di Wu🇨🇳 · Yifan Hu🇨🇳 · Kohei Kamada🇨🇳

    The generation of helical magnetic fields and the associated chiral asymmetry via the chiral anomaly is a generic feature in pseudoscalar inflation. In the presence of a Chern--Simons coupling between the inflaton and a U(1) gauge field, the homogeneous evolution of the inflaton induces a tachyonic instability in one circular polarization of the gauge field, resulting in the production of helical magnetic fields. In this work, we show that, in the case of a gauged lepton flavor symmetry, U(1)${}_{L_i-L_j}$, this mechanism can lead to the generation of a sizable lepton asymmetry. In a simple setup, however, the resulting lepton asymmetry is typically too small to have an observational consequences, even setting aside constraints from baryon overproduction via sphaleron processes, due to the backreaction of the produced gauge fields and fermions on the inflationary dynamics. We demonstrate that this limitation can be overcome by implementing a mechanism to suppress fermion production during inflation. As a result, a much larger lepton asymmetry can be generated from the subsequent decay of magnetic helicity. Remarkably, for the gauged U(1)${}_{L_{\mu }-L_{\tau }}$ symmetry, the generated asymmetry can be sufficiently large to suppress the primordial helium abundance, as may be inferred from recent cosmic microwave background observations by ACT.

    hep-phastro-ph.COJCAP(2026)·0 citations
13. 13*

    Dipion transitions from $X(3872)$ to ${\chi }_{cJ}(J=0,1,2)$

    Qi Wu🇨🇳 · Zhong-Quan Sun🇨🇳 · Dian-Yong Chen🇨🇳 · Shi-Dong Liu🇨🇳 · Gang Li🇨🇳

    In this work, we investigate the dipion transition processes $X(3872)\to \pi \pi {\chi }_{cJ}(J=0,1,2)$ within the framework of heavy hadron chiral perturbation theory, treating $X(3872)$ as a molecular state composed of $D{\bar{D}}^{\ast }$+ H.c. components. By analyzing the box and triangle loop diagrams with the nonrelativistic effective field theory power-counting rule, we demonstrate that box diagrams dominate these dipion transition processes. Branching ratios are calculated as functions of the mixing angle $\theta$, which parametrizes the neutral and charged meson compositions of the $X(3872)$. Our results indicate that the branching fractions for $X(3872)\to \pi \pi {\chi }_{c0}$, $X(3872)\to \pi \pi {\chi }_{c1}$, and $X(3872)\to \pi \pi {\chi }_{c2}$ are of the orders of $10^{-4}$, $10^{-3}$, and $10^{-5}$, respectively. We also predict the ratios $\mathcal{B}[X(3872)\to \pi \pi {\chi }_{c0/2}]/\mathcal{B}[X(3872)\to \pi \pi {\chi }_{c1}]$ and $\mathcal{B}[X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{cJ}]/\mathcal{B}[X(3872)\to {\pi }^0{\pi }^0{\chi }_{cJ}]$. The latter deviates from isospin-symmetry expectations, revealing various degrees of isospin violation. By studying the ${\pi }^{+}{\pi }^{-}$ and ${\pi }^{+}{\chi }_{cJ}$ invariant mass spectra, we find a double-bump structure in the ${\pi }^{+}{\pi }^{-}$ invariant mass distributions of the process $X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}$ and ${\pi }^{+}{\chi }_{c0}$ invariant mass distribution of the process $X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c0}$, which could be tested by future experimental measurements.

    hep-phPRD(2026)·3 citations
14. 14*

    Production of charmed particles in proton-proton and light nucleus-nucleus interactions in Geant4 FTF model

    A. Galoyan🇷🇺 · A. Ribon🇨🇭 · V. Uzhinsky🇷🇺

    The total yield of neutral D-mesons (4$\pi$) in central Xe+La interactions at 150 GeV per nucleon has been calculated within the Geant4 FTF model. Our calculation is close to predictions of Monte Carlo models that do not account for quark-gluon plasma formation. As the predictions, our calculation substantially underestimates preliminary experimental data. The experimental data indicate enhanced charmed particle production in nucleus-nucleus interactions. We present also our calculations for charmed meson production in $\mathrm{p}+\mathrm{p}$, $\mathrm{d}+\mathrm{d}$ and ${}^4\mathrm{He}{+}^4\mathrm{He}$ interactions for future NICA/SPD experiment at $\sqrt{s_{NN}}=$10 and 20 GeV.

    hep-ph0 citations
15. 15*

    Search for Light Dark Matter in Rare Meson Decays

    Ze-Kun Liu🇨🇳 · Ying Li🇨🇳 · Biao-Feng Hou🇨🇳 · Qin Chang🇨🇳

    Current dark matter direct detection experiments have low sensitivity to sub-GeV dark matter. In this work, we demonstrate that rare $B$ and $K$ meson decays with missing energy in the final state can serve as efficient probes in this mass range. We analyze a generic $Z^{\prime }$ portal dark matter model and derive upper limits on its parameters from experimental bounds on the rare $B$ and $K$ meson decays. Our results show that such meson decay processes provide complementary constraints to current direct detection experiments for sub-GeV dark matter, particularly for interaction forms mediated by dark matter momentum-dependent operators.

    hep-phPRD(2026)·5 citations
16. 16*

    Can Randomness lead to non-anarchical mixing angles ?

    Aadarsh Singh🇮🇳 · Sudhir K Vempati🇮🇳

    We revisit the proposal of Craig and Sutherland that Anderson localization in a disordered fermion theory space can generate small neutrino masses from TeV scale physics \citecraig2018exponential}. Building on this idea, we ask a broader question: can randomness in fermion mass parameters also give rise to nonanarchical neutrino mixing angles, and how does the answer depend on the geometry of the mass graph? To explore this, we analyse three representative geometries a nearest neighbour chain, a fully connected non local model, and the Petersen graph in both Dirac and Majorana neutrino realisations. In the regime of strong diagonal disorder, all geometries display robust localization and naturally generate the observed neutrino mass scale, with the corresponding flavour mixing angles reflecting the random localization centres and thus taking an anarchical form. In the regime of weak disorder, where localization is milder, and eigenmodes can exhibit quasidegeneracies, light neutrino masses can emerge through GIM-mechanismlike cancellations among the heavy states. The weak disorder with geometry dependent weak localization constitutes a distinct pathway to structured mixings within disordered theory spaces. Overall, our results delineate the regimes in which disorder driven mechanisms produce hierarchical masses and identify the conditions under which structured flavour mixing can arise.

    hep-phhep-th1 citation
17. 17*

    Quantum entanglement between partons in a strongly coupled quantum field theory

    Wenyu Zhang🇨🇳 · Wenyang Qian🇪🇸 · Yiyu Zhou🇮🇹 · Yang Li🇨🇳 · Qun Wang🇨🇳

    We perform a first-principles, non-perturbative investigation of quantum entanglement between partonic constituents in a strongly coupled 3+1-dimensional scalar Yukawa theory, using light-front Hamiltonian methods with controlled Fock-space truncations. By explicitly constructing reduced density matrices for (mock) nucleon, pion, and anti-nucleon subsystems from light-front wave functions, we compute key entanglement witnesses, including von Neumann entropy, mutual information, and linear entropy, in both quenched (no sea pairs) and unquenched frameworks. We find that the entanglement entropy is closely related to the Shannon entropy of the transverse momentum dependent distribution, establishing a link between quantum information and parton structure. In contrast, the unquenched theory reveals genuinely non-classical correlations: the entanglement entropy cannot be reduced to any Shannon entropy of normalized parton distributions, demonstrating that the full hadronic wave function encodes quantum information beyond classical probabilities. Our findings highlight the role of entanglement as a fundamental probe of non-perturbative dynamics in relativistic quantum field theory and lay the groundwork for extending these concepts to QCD and future collider phenomenology.

    hep-phhep-thnucl-thquant-phJHEP(2026)·8 citations
18. 18*

    Study of SIDIS Unpolarized Cross Sections from a ${}^3$He Target with the Solenoidal Large Intensity Device at JLab

    Matteo Cerutti🇫🇷 · Jian-Ping Chen🇺🇸 · Umberto D'Alesio🇮🇹 · Haiyan Gao🇺🇸 · Shuo Jia🇺🇸 · Vladimir Khachatryan🇺🇸 · Alexei Prokudin🇺🇸 · Lorenzo Rossi🇮🇹 · Ye Tian🇺🇸 · Zhiwen Zhao🇺🇸

    In this paper we present a detailed impact study of semi-inclusive deep inelastic scattering unpolarized cross sections' measurements using the proposed SoLID apparatus at Jefferson Lab. This type of data, collected at large Bjorken $x_{bj}$, moderate values of $Q^2$ and small values of the transverse momentum of produced hadrons, $P_{hT}$, allows to study transverse momentum dependent (TMD) parton distribution and fragmentation functions in a still poorly explored region. We present the projected results for charged light mesons based on simulated data. For the azimuthal-angle integrated cross sections we adopt the TMD framework up to the next-to-next-to-next-to-leading-logarithmic (N3LL) accuracy, while a simpler TMD parton model is employed for the study of azimuthal angular dependencies.

    ↳ nucl-exhep-phnucl-thPRC(2026)·1 citation
19. 19*

    Coherent-field QED transitions based on coherent-state boundary conditions

    Keita Seto🇯🇵

    We develop a coherent-field formulation of quantum electrodynamics (QED) based on coherent-state boundary conditions, in which laser fields are represented by asymptotic coherent states rather than by prescribed classical background fields. Starting from coherent-state boundary conditions and the displacement-operator formalism, we construct operator and path-integral descriptions of transitions between distinct electromagnetic coherent states. This formulation provides a coherent-field extension of conventional background-field QED and incorporates the quantum dynamics of the coherent field itself. The corresponding path-integral representation contains a functional integral over coherent-field histories in addition to the usual functional integral over quantum fluctuations, thereby extending the conventional background-field description. The resulting path-integral representation naturally leads to an effective action for the stationary coherent-field configuration. The corresponding saddle-point condition yields an effective Maxwell equation containing contributions from vacuum polarization, photon fluctuations, and coherent-field fluctuations. In the limit where the latter two contributions vanish, the formalism reduces to the conventional Heisenberg-Euler description.

    ↳ physics.plasm-phhep-phphysics.opticsquant-phAnnals Phys.(2026)·0 citations
20. 20*

    Evolution of the 2021 Outburst of GX 339-4 with AstroSat

    Vaibhav Sharma🇮🇳 · Ranjeev Misra🇮🇳 · J S Yadav🇮🇳 · Akash Garg🇮🇳 · Pankaj Jain🇮🇳

    We present a comprehensive study of the 2021 outburst of GX 339-4 using AstroSat observations in the hard-intermediate (HIMS) and soft-intermediate states (SIMS). Spectral and timing analyses across these states suggest that during the SIMS, unabsorbed flux (0.1-3 keV), inner disc temperature, and "apparent" inner disc radius do not change, suggesting the stability of the disc. In the SIMS, the photon index decreases from 2.1 to 1.7, indicating spectral hardening. The power density spectra (PDS) suggest the presence of quasi-periodic oscillations (QPOs) in the HIMS and SIMS. The QPO frequency evolves from 0.1 Hz to 0.2 Hz in the HIMS, and further to 5.7 Hz in the SIMS. We also observe a decrease in QPO frequency from 5.7 Hz to 4.5 Hz during the SIMS. We discuss the evolution of the QPO, fractional root mean square (rms) amplitude, and time-lag spectra. We discover that variations in disc normalization, disc temperature, and coronal heating rate can reproduce the observed rms and lag spectra with a time delay between them.

    ↳ astro-ph.HEhep-phMNRAS(2026)·2 citations
21. 21*

    Acoustic gravitational waves from primordial curvature perturbations

    Zhuan Ning🇨🇳 · Zi-Yan Yuwen🇰🇷 · Xiang-Xi Zeng🇨🇳 · Rong-Gen Cai🇨🇳 · Shao-Jiang Wang🇨🇳

    Standard perturbative calculations of scalar-induced gravitational waves (SIGWs) have neglected nonperturbative effects in the large-amplitude regime. We develop a hybrid numerical framework to signify nonperturbative effects on the stochastic gravitational wave (GW) background sourced by primordial curvature perturbations, focusing on the acoustic channel (fluid motions). Fully general-relativistic, spherically symmetric simulations are used to extract nonperturbative sound-shell profiles from isolated curvature peaks; these profiles are then embedded into three-dimensional lattice evolutions of relativistic hydrodynamics coupled to transverse-traceless metric perturbations to compute the acoustic GW spectra. The acoustic signal has a peak frequency determined by the comoving shell thickness, and its amplitude is extremely sensitive to the mean comoving separation of peaks, scaling approximately as $R_{\ast c}^{-7}$. We find a robust causal low-frequency tail $\propto k^3$, and the nonlinear hydrodynamic interactions can enhance the ultraviolet power. Comparing with SIGWs computed perturbatively from the same real-space configuration, we show that acoustic GWs can be amplified by an order of magnitude and display a peak shifted to a lower frequency in the large-amplitude regime. These results highlight the importance of nonperturbative effects for accurate predictions of stochastic GW signals induced from primordial curvature perturbations.

    ↳ gr-qcastro-ph.COhep-ph10 citations
22. 22*

    Twisted Feynman Integrals: from generating functions to spin-resummed post-Minkowskian dynamics

    Joon-Hwi Kim🇺🇸 · Jung-Wook Kim🇨🇭 · Jungwon Lim🇩🇪

    We propose to call a class of deformed Feynman integrals as twisted Feynman integrals, where the integrand has an additional exponential factor linear in loop momenta. Such integrals appear in various contexts: tensor reduction of Feynman integrals, Fourier transform of Feynman integrals, and spin-resummed dynamics in post-Minkowskian gravity. First, we construct a mathematical framework that manifests the geometric interpretation of twisted Feynman integrals. Next, we generalise the standard mathematical tools for studying Feynman integrals for application to their twisted cousins, and explore their mathematical properties. In particular, it is found that (i) Symanzik polynomials are no longer homogeneous and become graded, (ii) twisted Feynman integrals fall under the class of exponential periods, and (iii) the geometry of the function space cannot be inferred from the leading singularity computed through the (generalised) Baikov parametrisation of twisted Feynman integrals.

    ↳ hep-thhep-ph0 citations
23. 23*

    When Geometry Radiates Review: Gravitational Waves in Theory, Cosmology, and Observation

    Azadeh Maleknejad🇬🇧

    Gravitational waves provide a unique window into gravity, cosmology, and high-energy physics, enabling the exploration of fundamental phenomena across a wide range of scales. This review presents a coherent and pedagogical framework that bridges foundational theory with observational frontiers. We begin by developing the theory of gravitational radiation within linearized general relativity, deriving gravitational waves as solutions to the linearized Einstein equations and clarifying their physical interpretation, polarization states, and key properties. We then deepen the discussion through a geometric perspective, tracing the connection between gravitational radiation and the algebraic structure of the Weyl tensor and its role in defining energy and angular momentum in asymptotically flat spacetimes. Extending beyond flat backgrounds, we examine gravitational waves in an expanding universe, following their evolution across cosmological epochs and their generation during inflation. Within this setting, we discuss adiabatic modes and consistency relations that reveal universal properties of long-wavelength perturbations, and derive the inflationary spectrum of vacuum gravitational waves together with their contribution to the integrated Sachs-Wolfe effect. We also survey the main observational strategies for detecting gravitational waves across a broad frequency range, including cosmic microwave background polarization, pulsar timing arrays, ground- and space-based laser interferometers, and resonant cavity detectors. We then discuss the astrophysical and cosmological mechanisms responsible for generating gravitational radiation. We conclude by summarizing the current status of the field and outlining promising directions for future theoretical and observational developments.

    ↳ gr-qcastro-ph.COhep-phhep-th6 citations
24. 24*

    Demystifying stringy miracles with eclectic flavor symmetries

    V. Knapp-Perez🇺🇸 · Xiang-Gan Liu🇺🇸 · Hans Peter Nilles🇩🇪 · Saul Ramos-Sanchez🇲🇽

    Effective field theories arising from string compactifications are subject to constraints originating from the duality transformations of string theory. Interpreting these so-called selection rules in terms of conventional symmetries has remained challenging. We show that particular selection rules in heterotic orbifolds can be explained from a subtle interplay between modular and traditional flavor symmetries within the eclectic flavor framework.

    ↳ hep-thhep-phPRD(2026)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.