Fri·Dec 12, 2025Friday·December 12, 2025

1. 01*

   The Four Polarizations of the $W$ at High Energies

   Trina Basu🇵🇱 · Richard Ruiz🇵🇱

   We investigate polarization-induced interference, off-shell effects, and gauge cancellations in predictions for high-energy, multi-leg processes with (near) resonant weak bosons. Building on the ``polarized propagator'' paradigm, we carry out our analysis at the level of helicity amplitudes and squared amplitudes, computing polarization interference directly. We introduce analytical decompositions of polarized propagators, valid for covariant and axial gauges, that simplify the organization and evaluation of polarized amplitudes, and make power counting of mass-over-energy factors manifest. We show: (i) For the fully massive case, polarization interference can exceed $\mathcal{O}({\Gamma }_V^2/M_V^2)$ width-over-mass corrections, limiting the applicability of the narrow width and pole approximation at low energies. (ii) At the fully differential level, interference can naturally be larger than squared longitudinal amplitudes but can also vanish when bosons are emitted by unpolarized sources. (iii) When weak bosons decay to massless fermions, the non-interference of polarization after angular integration extends to the off-shell regime but remains approximate due to $V-A$ couplings. Guided by BRST invariance, we propose a simple scheme for grouping together polarizations that reduces gauge ambiguities in predictions for polarized scattering rates and is applicable to the fully massive case. As case studies, we examine polarization interference in $W$(+jets), top quark decay, and neutrino deep-inelastic scattering. For decays of unpolarized top quarks, interference exactly cancels at the totally unintegrated level.

   hep-phhep-exhep-th5 citations
2. 02*

   Living on the edge: radius effects in the angular substructure of heavy-ion jets

   Carlota Andres🇫🇷 · Jack Holguin🇬🇧 · Benjamin Kimelman🇺🇸 · Raghav Kunnawalkam Elayavalli🇺🇸 · Jussi Viinikainen🇺🇸 · Zhong Yang🇺🇸

   Jet substructure observables serve as essential tools for probing the quark-gluon plasma produced in relativistic heavy-ion collisions. Their interpretation, however, is often complicated by edge effects, which arise when correlated particles fall outside the reconstructed jet radius, introducing distortions that obscure the underlying QCD dynamics. In this work, we present a comprehensive phenomenological study of edge effects in soft-insensitive angular observables, taking the two-point energy correlator (EEC) as a representative example. We argue that these distortions scale linearly with the average angular separation between the winner-take-all and $E$-scheme axes $⟨\varphi ⟩$, and validate this behavior across proton-proton (p-p) simulations with Pythia8 and Herwig7, as well as lead-lead (Pb-Pb) simulations using JEWEL and CoLBT. In p-p collisions, edge effects are strongly suppressed, scaling as $(R_L/R{)}^4$, whereas medium-modified jets can exhibit larger distortions, with contributions scaling as $(R_L/R{)}^2$ and $(R_L/R{)}^4$. Taking Pb-Pb/p-p ratios of the EEC substantially reduces, but does not completely eliminate, these distortions, highlighting the need of accounting for edge effects in the interpretation of heavy-ion jet substructure measurements. Since edge effects are largely governed by the $⟨\varphi ⟩$ distribution, studying this distribution provides a new handle for benchmarking and constraining the modeling of edge effects in heavy-ion event generators.

   hep-phhep-exnucl-exnucl-th5 citations
3. 03*

   Constraining non-commutative geometry with W/Z+jet production at the LHC

   Achwaq Ghezal🇩🇿 · Yazid Delenda🇩🇿 · Mekki Aouachria🇩🇿

   We present a comprehensive calculation of the squared matrix elements for all partonic channels contributing to $W^{\pm }/Z$+jet production at hadron colliders within the framework of the non-commutative Standard Model (NCSM), including leptonic decays $W\to e\nu$ and $Z\to {\mu }^{+}{\mu }^{-}$. Our computation incorporates both $\mathcal{O}(\Theta )$ corrections to the Standard Model vertices and additional interaction terms inherent to the NCSM. A key finding is that the production amplitudes receive first-order corrections at $\mathcal{O}(\Theta )$, a distinctive feature compared to many other processes where non-commutative effects enter only at $\mathcal{O}({\Theta }^2)$. The leptonic decay widths, in contrast, are modified solely at $\mathcal{O}({\Theta }^2)$. This $\mathcal{O}(\Theta )$ enhancement provides improved sensitivity to non-commutative geometry, allowing us to probe for and constrain the non-commutative energy scale in the multi-TeV range. We provide numerical predictions for angular (azimuthal and rapidity) distributions and the forward--backward asymmetry, and compare them to state-of-the-art Standard Model predictions at leading and next-to-leading order from the \texttt{MCFM} Monte Carlo program. Finally, we test the NCSM with experimental data by analyzing an unbinned, particle-level $Z$+jet dataset from the ATLAS experiment. From this data, we calculate the azimuthal spectrum and forward-backward asymmetry, which are then used to derive stringent lower bounds on the non-commutative scale $\Lambda$. Our analysis accounts for Earth rotation effects by treating the non-commutative tensor as fixed in a celestial frame and deriving time-averaged observables in the rotating detector frame.

   hep-phInt.J.Mod.Phys.A(2026)·0 citations
4. 04*

   Potential for the discovery of the protophobic boson at the STCF

   Althaf M.🇮🇳 · Triparno Bandyopadhyay🇮🇳

   We study the morphology of the main drift chamber (MDC) to be built around the collision point of the proposed Super tau-charm facility (STCF), to check its suitability for discovering the 17 MeV protophobic boson (X17 boson), hypothesised as a solution to the persistent ATOMKI nuclear-transition anomalies. Using the TrackEff framework, we perform detector-level simulations of the STCF MDC, and evaluate displaced-vertex sensitivities towards the protophobic boson, across the relevant mass-coupling parameter space. We study benchmark scenarios with visible and dark decay channels to perform likelihood-based significance estimates in order to determine the 5~$\sigma$ discovery reach for the protophobic boson. We find that STCF can potentially discover the protophobic boson while tolerating $\sim 10^4$ background events for specific regions of the parameter space. Our analysis establishes the first feasibility study of displaced light-boson searches at the STCF, motivating a full Geant-4 simulation.

   hep-phhep-exJHEP(2026)·1 citation
5. 05*

   Unpolarized GPDs at small $x$ and non-zero skewness

   Yuri V. Kovchegov🇺🇸 · M. Gabriel Santiago🇺🇸 · Huachen Sun🇺🇸

   We study the small-$x$ asymptotics of unpolarized generalized parton distributions (GPDs) and generalized transverse momentum distributions (GTMDs). Unlike the previous works in the literature, we consider the case of non-zero (but small) skewness while allowing for non-linear contributions to the evolution equations. We show that unpolarized GPDs and GTMDs at small $x$ are related to the eikonal dipole amplitude $N$, whose small-$x$ evolution is given by the BK/JIMWLK evolution equations, and to the odderon amplitude $\mathcal{O}$, whose evolution is also known in the literature. We show that the effect of non-zero skewness $\xi \ne 0$ is to modify the value of the evolution parameter (rapidity) in the arguments for the dipole amplitudes $N$ and $\mathcal{O}$ from $Y=\ln (1/x)$ to $Y=\ln \min \left\{1/|x|,1/|\xi |\right\}$.

   hep-phnucl-thPLB(2026)·9 citations
6. 06*

   Towards the Direct Detection of Composite Ultraheavy Dark Matter in Quantum Sensor Arrays

   Dorian W. P. Amaral🇺🇸 · Erqian Cai🇺🇸 · Andrew J. Long🇺🇸 · Juehang Qin🇺🇸 · Christopher D. Tunnell🇺🇸

   Quantum sensor arrays have recently been proposed as a promising platform for the direct detection of ultraheavy dark matter, which is typically assumed to behave as a point-like particle. However, particles with masses at or above the Planck scale cannot be elementary; instead, they must exist as composite objects with finite spatial extent. Such spatially extended dark matter models lead to distinctive phenomenology in these detectors, particularly when the dark matter also interacts through long-range forces with their own characteristic length scales. In this work, we study the sensitivity of quantum sensor arrays to composite, ultraheavy dark matter interacting via both gravity and a novel Yukawa force. We consider three phenomenologically motivated density profiles -- a tophat, a Gaussian, and an exponential -- and contrast their signals with the point-like limit. Using a Monte Carlo analysis based on the predicted impulse signals and estimates of thermal and quantum noise, we obtain sensitivity projections for a future realization of a quantum sensor array. We find a non-trivial interplay between the dark-matter scale radius, the inter-sensor spacing, and the Yukawa screening length. Future accelerometer arrays would provide valuable information about the mass and size of composite ultraheavy dark matter, and our work will help to characterize the signatures of different theoretical models of ultraheavy dark matter.

   hep-phhep-exJCAP(2026)·3 citations
7. 07*

   Hadronic contributions to $a_{\mu }$ within Resonance Chiral Theory

   Emilio J. Estrada🇲🇽 · Alejandro Miranda🇪🇸 · Pablo Roig🇲🇽

   We review the recent progress achieved, using Resonance Chiral Theory, in the hadronic contributions to the muon anomalous magnetic moment. These include the hadronic vacuum polarization, either using $e^{+}{e}^{-}$ or $\tau$ decays into hadron final states as input; and the hadronic light-by-light part, where in addition to previous results on the lightest pseudoscalar and tensor-poles contributions, we first present the evaluation of the pseudoscalar box using this formalism. We also discuss the scalar, axial-pole and other subleading pieces. The results obtained are consistent with the White Paper 2 values, with comparable precision.

   hep-phhep-exhep-latEur.Phys.J.ST(2026)·1 citation
8. 08*

   Perturbative limits on axion-SU(2) gauge dynamics during inflation from the energy density of spin-2 particles

   Koji Ishiwata🇯🇵 · Eiichiro Komatsu🇩🇪

   We investigate the conditions under which the perturbative treatment of the backreaction of spin-2 particles on the dynamics of an axion-SU(2) gauge field system breaks down during cosmic inflation. This condition is based on the ratio of the energy density of spin-2 particles from the SU(2) gauge field to that of the background field. The perturbative treatment breaks down when this ratio exceeds unity. We show that this occurs within a parameter space nearly identical to the strong backreaction regime identified in previous studies. However, in some cases, the ratio exceeds unity even before the system enters the strong backreaction regime. Our results suggest that attempts to study the strong backreaction regime using perturbation theory are necessarily limited. Reliable calculations require non-perturbative treatments, such as three-dimensional lattice simulations.

   hep-phJCAP(2026)·5 citations
9. 09*

   Studies on quark-mass dependence of the $N^{\ast }(920)$ pole from $\pi N$ $\chi$PT amplitudes

   Xu Wang🇨🇳 · Kai-Ge Kang🇨🇳 · Qu-Zhi Li🇨🇳 · Zhiguang Xiao🇨🇳 · Han-Qing Zheng🇨🇳

   The quark-mass dependence of the $N^{\ast }(920)$ pole is analyzed using $K$-matrix method, with the $\pi N$ scattering amplitude calculated up to $O(p^3)$ order in chiral perturbation theory. As the quark mass increases, the $N^{\ast }(920)$ pole gradually approaches the real axis in the complex $w$-plane (where $w=\sqrt{s}$). Eventually, in the $O(p^2)$ case, it crosses the $u$-cut on the real axis and enters the adjacent Riemann sheet when the pion mass reaches $526\mathrm{MeV}$. At order $O(p^3)$, the rate at which it approaches the real axis slows down; however, we argue that it will ultimately cross the $u$-cut and enter the adjacent Riemann sheet as well. Additionally, the trajectory of the \(N^*(920)\) pole is in qualitative agreement with the results from the linear $\sigma$ model calculation.

   hep-phhep-latCPC(2026)·0 citations
10. 10*

    A unified approach for the hadronic weak decays of $\Lambda$ and ${\Sigma }^{\pm }\to N\pi$

    Ye Cao🇨🇳 · Ming-Xiao Duan🇨🇳 · Zhong Tao🇨🇳 · Qiang Zhao🇨🇳

    We provide a unified approach for the two-body hadronic weak decays of hyperons with $S=-1$, i.e. $\Lambda$ and ${\Sigma }^{\pm }$, in the framework of the non-relativistic constitute quark model (NRCQM). A combined analysis shows that the branching ratios and asymmetry parameters of the decay channels $\Lambda \to p{\pi }^{-}$ and ${\Sigma }^{\pm }\to N\pi$ can be well described in the same framework with the direct pion emission, color suppressed internal $W$ emission, and pole terms included. However, the channel $\Lambda \to n{\pi }^0$ indicates significant deviations from the experimental data based on these mentioned transition mechanism. We demonstrate that the final state interactions (FSIs) via the coupled-channel rescatterings play a crucial role in $\Lambda \to n{\pi }^0$. Namely, the dominant decay channel of $\Lambda \to p{\pi }^{-}$ can contribute to $\Lambda \to n{\pi }^0$ via the $p{\pi }^{-}\to n{\pi }^0$ rescatterings. This is a leading correction effect for $\Lambda \to n{\pi }^0$ at the one-loop level. We find that such FSIs only become the leading effects in $\Lambda \to n{\pi }^0$, but contribute as subleading contributions in other channels. We also demonstrate that the pole terms are indispensable in these hyperon decays. In particular, for ${\Sigma }^{-}\to n{\pi }^{-}$ and ${\Sigma }^{+}\to n{\pi }^{+}$, it shows that $\Lambda (1405)$ as the intermediate state in the pole term amplitude is necessary for reproducing the experimental data. We also find that a dynamic selection rule forbids the radial excitation state $N(1710)$ of the quark model multiplet $|70{,}^{2}8,2,0^{+},1/2^{+}⟩$ from contribution. To some extent, the hyperon hadronic weak decays serve as a special probe for the underlying transition mechanisms and can provide some constraints on the intermediate $J^P=1/2^{\pm }$ baryon resonances.

    hep-phhep-exnucl-th2 citations
11. 11*

    Yukawa-assisted charged-lepton dipoles in resonant electromagnetic leptogenesis

    Rin Takada🇯🇵

    We study the charged-lepton dipole contribution that is linear in the neutrino-dipole coefficients $C_{NB,NW}$ and in the renormalizable neutrino Yukawa matrix $Y_{\nu }$. We consider a resonant EMLG benchmark with dipole-sector coefficients renormalized at ${\kappa }_N=M_1=1\mathrm{TeV}$ and evolved through the coupled one-loop RGE to ${\kappa }_{\mathrm{match}}=3\mathrm{TeV}$, a factorized flavor structure, and ${\tilde{m}}_1^{\mathrm{EM}}=3.97\times 10^{-2}\mathrm{eV}$. Since these inputs do not determine $Y_{\nu }$, we impose the conditional width bound ${\Gamma }_Y^{(0)}⩽ϵ{\Gamma }_{\mathrm{EM}}^{(0)}$ and a vanishing direct ultraviolet charged-lepton dipole, derive the one-loop $\nu$SMEFT leading logarithm, and apply the tree-level electroweak projection and one-loop QED evolution in LEFT. For $ϵ=10^{-2}$ and two coherently aligned heavy states, the width-only envelopes are $\mathrm{BR}(\mu \to e\gamma )⩽2.77\times 10^{-28}$, $|d_e|⩽5.71\times 10^{-37}e\mathrm{cm}$, and $|\Delta a_{\mu }|⩽1.31\times 10^{-21}$. The factorized flavor structure and $C_{NW}/C_{NB}=1.739$ give smaller conditional bounds. The benchmark phase ${\varphi }_{BW}=0$, for which ${\rho }_{BW}=+1.739$, lies near the charged-lepton photon-dipole blind direction. The vacuum local coefficient contains no resonant pole denominator. The two thermal pole prescriptions enter the low-energy comparison only through the mass splittings selected by the transport calculation, producing a relative change of order $\Delta M/M_1$.

    hep-ph0 citations
12. 12*

    Probing the di-$J/\Psi$ interaction and the nature of $X(6200)$ with femtoscopic correlation functions

    Zhi-Wei Liu🇨🇳 · Jia-Ming Xie🇨🇳 · Jun-Xu Lu🇨🇳 · Li-Sheng Geng🇨🇳

    Recent re-analyses of the di-$J/\Psi$ invariant mass spectra reveal a state near the di-$J/\Psi$ threshold, referred to as the $X(6200)$. Yet the nature of this near-threshold pole--whether it is a resonant, bound, or virtual state--remains unresolved due to our limited understanding of the di-$J/\Psi$ interaction. To address this question, we predict the di-$J/\Psi$ and $J/\Psi \Psi (2S)$ femtoscopic correlation functions based on the Koonin-Pratt formula with a Gaussian source and the coupled-channel dynamics. Our results show that the di-$J/\Psi$ correlation function exhibits distinctly different behaviors in each scenario, especially for small source sizes ($R\sim 1$ fm), providing a clear experimental observable to distinguish the nature of $X(6200)$. These distinguishing features persist even when quantum statistical effects and coupled-channel dynamics are included and show negligible sensitivity to off-shell ambiguities. Given the high $J/\Psi$ production rates and clean detection channels at the LHC, we hope that these discoveries will stimulate further experimental studies and help clarify the nature of double-vector-charmonium interactions and the nonperturbative dynamics of fully-heavy tetraquark systems.

    hep-ph9 citations
13. 13*

    Renormalization group evolution induced breaking of $\mu -\tau$ reflection symmetry in MSSM with effects of variation of $tan\beta$

    Chandan Kumar Borah🇮🇳 · Chandan Duarah🇮🇳

    We study the renormalization group (RG) evolution induced breaking of $\mu$--$\tau$ reflection symmetry in the Minimal Supersymmetric Standard Model (MSSM), with a special focus on the effects of varying $\tan \beta \equiv v_u/v_d$, the ratio of MSSM Higgs vacuum expectation values. Starting from an exact $\mu$--$\tau$ reflection symmetry imposed at a high flavor symmetry scale ${\Lambda }_{\text{FS}}$, we run the complete set of coupled RGEs for neutrino masses, mixing angles, and CP-violating phases down to the electroweak scale, imparting perturbation to the symmetry. We consider a specific value of the SUSY breaking scale, ${\Lambda }_s=7TeV$ during the run. By choosing suitable free parameters at the high-energy scale, we reproduce the low-energy experimental constraints on neutrino observables consistent with $3\nu$ global analysis data. We then examine how the breaking of $\mu$--$\tau$ reflection symmetry is influenced by different values of $\tan \beta$, considering three benchmark choices. In addition, the analysis is performed for both normal ordering (NO) and inverted ordering (IO) of neutrino masses to highlight potential differences in their RG running behavior.

    hep-phInt.J.Mod.Phys.A(2026)·2 citations
14. 14*

    Quantization of massive Dirac neutrinos in external fields

    Maxim Dvornikov (IZMIRAN)🇷🇺

    We review the applications of the quantum field theory (QFT) for the description of massive Dirac neutrinos in external fields. Two particular cases of external background are considered. First, we examine neutrinos in background matter. Then, we study neutrinos with anomalous magnetic moments in a magnetic field. In both situations, we derive the operator valued neutrino wavefunctions, accounting for external fields, which obey the canonical anticommutation relations. Then, we check that the total energy and momentum of a neutrino field have the appropriate forms. Using the exact solution in a Dirac equation in a magnetic field, we also derive the propagator for a massive Dirac neutrino in this external background. The results obtained are of importance for the QFT application to neutrino oscillations in external fields.

    hep-phhep-th0 citations
15. 15*

    Three-body resonances of $\alpha \alpha M$ clusters ($M=\varphi$, $J/\psi$, ${\eta }_c$) in ${}_M^8\mathrm{Be}$ nuclei

    Hao Zhou🇨🇳 · Xiang Liu🇨🇳

    Motivated by the recently obtained HAL QCD potentials for the $N$-$\varphi$, $N$-$J/\psi$, and $N$-${\eta }_c$ interactions, we investigate the structure of the exotic nuclei ${}_{\varphi }^8\text{Be}$, ${}_{J/\psi }^8\text{Be}$, and ${}_{{\eta }_c}^8\text{Be}$ as $\alpha +\alpha +M$ three-body systems ($M$ denotes the meson). The bound and resonant states are calculated consistently using the Gaussian expansion method, with resonances identified via the complex scaling method. For the $\alpha \varphi$ and $\alpha$-charmonium interactions, a folding potential is constructed based on the HAL QCD potentials and fitted to a Woods-Saxon form. We find that the $\varphi$ meson exhibits a strong ``glue-like" effect, binding the $0_1^{+}$, $2_1^{+}$, and $4_1^{+}$ resonant states of ${}^8$Be into stable states and significantly reducing the $\alpha$-$\alpha$ distance. In contrast, the interactions of $J/\psi$ and ${\eta }_c$ with the nucleus are weaker, forming only shallow bound states with the $0_1^{+}$ state of ${}^8$Be and even increasing the $\alpha$-$\alpha$ separation. Notably, our analysis predicts weakly bound $\alpha$-$J/\psi$ states in the ${}^4{S}_{3/2}$ and ${}^2{S}_{1/2}$ channels, a result not reported in prior studies, which suggests that ${}_{J/\psi }^8\text{Be}$ may not be a Borromean nucleus. The sensitivity of the ${}_M^8\mathrm{Be}(4_1^{+})$ state-transitioning from bound to resonant depending on the $\alpha$-particle radius-highlights the subtle dynamics at play. These results provide a systematic theoretical comparison of how different vector mesons modify nuclear clustering, offering critical predictions for future experimental searches of such exotic hadron-nucleus systems.

    hep-phhep-exnucl-exnucl-thPRD(2026)·3 citations
16. 16*

    Disperon QED

    Yizhou Fang🇨🇭 · Sophie Kollatzsch🇨🇭 · Marco Rocco🇮🇹 · Adrian Signer🇨🇭 · Yannick Ulrich🇬🇧 · Max Zoller🇨🇭

    We present disperon QED, a method to deal with data input in loop processes in Monte Carlo codes. It relies on dispersion relations, automated tools such as OpenLoops, effective field theory methods and a threshold subtraction. We motivate this method and apply it to the process $ee\to \pi \pi$ in McMule to deal with hadronic vacuum polarisation insertions in two-loop contributions as well as the vector form factor of the pion within the form-factor scalar QED approximation. The generality of this method for more complicated processes is emphasised.

    hep-phhep-exnucl-thSciPost Phys.(2026)·10 citations
17. 17*

    Approximate N${}^2$LO and N${}^3$LO QCD Predictions for $tW$ Production

    Jia-Le Ding🇨🇳 · Hai Tao Li🇨🇳 · Jian Wang🇨🇳

    We present high-precision predictions for associated $tW$ production at the LHC that incorporate the next-to-next-to-leading order hard and soft functions as well as the complete next-to-next-to-next-to-leading order scale-dependent terms derived from the corresponding anomalous dimensions. These higher-order corrections, which dominate the full perturbative results, increase the next-to-leading order cross section by more than 10\%. Based on the comparison with ATLAS and CMS measurements, we directly extract the Cabibbo-Kobayashi-Maskawa matrix element $|V_{tb}|=0.99\pm 0.03(\mathrm{expt})\pm 0.03(\mathrm{theor})$ without assuming unitarity, achieving a precision comparable with the current world average value.

    hep-phhep-exPRD(2026)·1 citation
18. 18*

    Partial $A_4$ flavor symmetry of the leptonic 3HDM

    Bartosz Dziewit🇵🇱 · Marek Zrałek🇵🇱 · Joris Vergeest🇵🇱

    When the Higgs doublets in the 3HDM transform as a flavor triplet of the $A_4$ group, the lepton mass matrices accommodate the experimental neutrino mixing angles at arbitrary precision while maintaining the correct mass ordering of the charged and neutral leptons, the latter being Dirac neutrinos in the normal spectrum. Under $A_4$ symmetry, also agreement of the lepton masses with experimental data is obtained for Higgs vacua differing from those for fitting $U_{\text{PMNS}}$. For groups of order equal or less than 600 no contractions different from the one found for $A_4$ yield better agreement with experimental data, and the solution structure presented is unique within the set of groups studied.

    hep-phActa Phys.Polon.Supp.(2026)·0 citations
19. 19*

    Exploring New Propagation Scales With Galactic Neutrinos

    Miller MacDonald🇺🇸 · Kiara Carloni🇺🇸 · Carlos A. Argüelles🇺🇸 · Ivan Martínez-Soler🇬🇧 · Rafael Alves Batista🇫🇷

    The recent observation of high-energy Galactic neutrinos by IceCube allows for searches of new physics affecting neutrino propagation on scales of $O(10^9-10^{15})km/GeV$ in distance over energy. We assess the sensitivity of upcoming measurements of Galactic neutrinos by IceCube and KM3NeT to such new phenomena. We focus on two scenarios: quasi-Dirac neutrinos and neutrino decays. In the quasi-Dirac scenario, we find that joint measurements by IceCube and KM3NeT are sensitive to the mass-squared differences $\delta m^2\in \left(10^{-13.6}\mathrm{e}{\mathrm{V}}^2,10^{-12.3}\mathrm{e}{\mathrm{V}}^2\right)$ at the $90\%$ confidence level. For neutrino decays, the same measurements are sensitive to mass over lifetime ratios $m/\tau >10^{-12.8}\mathrm{e}{\mathrm{V}}^2$ at the same significance. Our results demonstrate that measurements of Galactic neutrinos by a global network of neutrino telescopes can probe signatures of neutrino mass models.

    hep-phastro-ph.HE4 citations
20. 20*

    Electroweak right-handed neutrino portal dark matter

    Wan-Zhe Feng🇨🇳 · Ao Li🇨🇳 · Zong-Huan Ye🇨🇳 · Zi-Hui Zhang🇨🇳

    We study dark matter coupled to the Standard Model via electroweak scale right-handed neutrinos in a Type-I seesaw framework. We consider a minimal dark sector containing a fermion $\chi$ and a complex scalar $\varphi$ whose only connection to the Standard Model is through renormalizable Yukawa interactions with right-handed Majorana neutrinos, thus realizing a neutrino portal after seesaw mixing. We discuss three representative realizations of electroweak right-handed neutrinos arising from the Type-I seesaw mechanism, spanning small, tiny, and ultraweak couplings to the Standard Model sector, so that the dark particles can either undergo secluded freeze-out or be produced via freeze-in. Instead of merely estimating the order of magnitude of the seesaw couplings, we use the Particle Swarm Optimization algorithm to obtain viable seesaw parameter sets consistent with neutrino data and other constraints, and then compute the coupled evolution of the dark particles and right-handed neutrinos, reproducing the observed dark matter relic abundance in representative benchmark scenarios. For freeze-out, dark matter depletion is controlled by coupled dark sector dynamics, requiring a full Boltzmann treatment for a reliable relic abundance. For freeze-in, internal dark interactions also alter the relic density: treating hidden particles as independent components with late decays added afterward can misestimate the abundance by $30\%$ or even $95\%$, depending on the interaction structure. Electroweak right-handed neutrino portal dark matter thus provides a robust and predictive framework that tightly connects neutrino physics, heavy neutral lepton phenomenology, and the cosmological dark matter relic density, offering a well-motivated benchmark for complementary collider, neutrino, and cosmological probes at the high energy frontier.

    hep-phPRD(2026)·1 citation
21. 21*

    Additional results on the four-loop flavour-singlet splitting functions in QCD

    G. Falcioni (Turin U. and INFN, Turin)🇮🇹 · F. Herzog (U. Edinburgh, Higgs Ctr. Theor. Phys.)🇬🇧 · S. Moch (Hamburg U., Inst. Theor. Phys. II)🇩🇪 · A. Pelloni (Zurich, ETH)🇨🇭 · A. Vogt (Liverpool U., Dept. Math.)🇩🇪

    We have extended our previous computations, performed analytically for a general gauge group, of the even-$N$ moments ${\gamma }_{\mathrm{ik}}^{(3)}(N)$ of the four-loop flavour-singlet splitting functions $P_{\mathrm{ik}}^{(3)}(x)$ to $N=22$. The numerical QCD results perfectly agree with all predictions resulting from the approximations for $P_{\mathrm{ik}}^{(3)}(x)$ that we obtained before from the moments $N\le 20$ and endpoint constraints, confirming their reliability for collider-physics applications. Due to the additional analytical constraints provided by our new $N=22$ results, we are now closing in on determining the all-$N$ forms of all non-rational ($\zeta$-function) contributions to ${\gamma }_{\mathrm{ik}}^{(3)}(N)$: only the $n_f^0{\zeta }_3$ parts of the quark-to-gluon (gq) and the $n_f^1{\zeta }_3$ parts of the gluon-to-gluon (qg) cases still need to be completed. Finally we extend our approximations for all $P_{\mathrm{ik}}^{(3)}(x)$ to $n_f^{}=6$ light flavours and update those for $P_{\mathrm{gq}}^{(3)}(x)$ at lower $n_f^{}$.

    hep-phPLB(2026)·11 citations
22. 22*

    Nonlocal form factor of chromomagnetic penguin in $B\to K{\ell }^{+}{\ell }^{-}$ from QCD light-cone sum rules

    T. Hurth🇩🇪 · A. Khodjamirian🇩🇪 · F. Mahmoudi🇫🇷 · D. Mishra🇫🇷 · Y. Monceaux🇫🇷 · S. Neshatpour🇫🇷

    The branching fraction of the $B\to K{\ell }^{+}{\ell }^{-}$ decay has been measured recently by the LHC experiments, showing a deviation from theory predictions based on the Standard Model (SM). A major challenge in achieving a complete SM prediction and interpreting this discrepancy lies in the treatment of nonlocal hadronic effects. In $B\to K{\ell }^{+}{\ell }^{-}$, these effects are cast in a single nonlocal form factor, a function of squared momentum transfer $q^2$ to the lepton pair. One of the previously used methods provides this form factor in the region of spacelike momentum transfer, $q^2<0$, matching the result to the hadronic dispersion relation, which is then continued to the physical region. The calculation done so far was a combination of QCD factorisation for hard-gluon contributions with light-cone sum rules (LCSRs) for soft-gluon ones. In this work, we calculate for the first time the complete nonlocal form factor at $q^2<0$ for one of the effective operators, the chromomagnetic operator $O_{8g}$, applying the method of LCSRs with $B$-meson distribution amplitudes. We compute, both analytically and numerically, the operator-product expansion (OPE) diagrams with hard-gluon exchanges, analyse their structure and hierarchy, and obtain their spectral density entering the LCSR together with soft-gluon contributions. This study paves the way for our next task, a complete calculation of nonlocal $B\to K{\ell }^{+}{\ell }^{-}$ form factor at spacelike $q^2$, including the dominant contributions of current-current operators, known as charm-loops.

    hep-phJHEP(2026)·4 citations
23. 23*

    Standard Model Benchmarks for $D^0\to K^{-}{K}^{+},{\pi }^{-}{\pi }^{+},K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ Decays

    Robert Fleischer🇳🇱 · Maria Laura Piscopo🇳🇱 · K. Keri Vos🇳🇱 · B. Yağmur Zubaroğlu🇳🇱

    The non-leptonic $D^0\to K^{-}{K}^{+}$ and $D^0\to {\pi }^{-}{\pi }^{+}$ decays are powerful probes of the Standard Model and are related to each other through the $U$-spin symmetry of the strong interaction. Using lattice QCD inputs we calculate the corresponding colour-allowed tree amplitudes in factorisation and demonstrate that non-factorisable contributions and $U$-spin-breaking effects at the level of 50% allow us to accommodate the measured branching ratios in the Standard Model. An exciting direct probe of such non-factorisable and $U$-spin breaking effects is provided by the $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ channel. This decay is governed by non-factorisable exchange topologies and essentially vanishes in the $U$-spin limit, although it is experimentally well established with a prominent branching ratio. Extrapolating our $D^0\to K^{-}{K}^{+}$ results using the isospin symmetry, we find a consistent benchmark picture. Specifically, we can accommodate the measured $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ branching ratio with $U$-spin-breaking effects at the 50% level and exchange amplitudes at the level of 50% of the colour-allowed $D^0\to K^{-}{K}^{+}$, $D^0\to {\pi }^{-}{\pi }^{+}$ tree contributions. Finally, we explore the resulting range for direct CP violation in $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$, obtaining upper bounds in our benchmark scenarios of a few per mille, offering an exciting target for future measurements.

    hep-phhep-exJHEP(2026)·9 citations
24. 24*

    Hiding a Light Vector Boson from Terrestrial Experiments: A Chargephobic Dark Photon

    Haidar Esseili🇺🇸 · Graham D. Kribs🇺🇸

    We calculate the terrestrial, astrophysical and cosmological constraints on a light vector boson that couples to an arbitrary combination of the electromagnetic and $B-L$ currents of the Standard Model. The dark photon and a vector boson coupling to $B-L$ are special cases of our generalized flavor-universal anomaly-free vector boson, requiring just one additional parameter (the "dark mixing angle" corresponding to the linear combination of the electromagnetic and $B-L$ currents) beyond that of the overall coupling strength and the vector boson mass, where we focus on the range $1\mathrm{MeV}$ to $60\mathrm{GeV}$. We perform a detailed investigation of a unique combination where the vector boson couplings to electrically charged leptons and protons are highly suppressed: the "chargephobic dark photon". A chargephobic vector boson is very weakly constrained by current terrestrial experiments including beam dumps and collider experiments, since they rely on couplings to electrons and protons. Instead, neutrino scattering experiments (such as COHERENT), astrophysical sources (supernova emission), and cosmology ($\Delta N_{\mathrm{eff}}$) provide the strongest constraints due to the nonzero couplings of the chargephobic vector boson to neutrinos and neutrons. Indeed, we find that supernova emission and $\Delta N_{\mathrm{eff}}$ provide constraints throughout the space of dark mixing angles, demonstrating their importance to provide model-independent constraints. For nearly all of the parameter space, a chargephobic vector boson is the most weakly constrained anomaly-free vector boson that couples to flavor-independent or flavor-dependent combinations of Standard Model currents. Finally, we highlight the importance of future experiments, including SHiP, that are able to probe new regions of the chargephobic parameter space due to the significantly improved detector capabilities.

    hep-phPRD(2026)·4 citations
25. 25*

    Heterogeneous Cosmological Phase Transitions: Seeded by Domain Walls and Junctions

    Yang Bai🇺🇸 · Yifu Xu🇬🇧 · Yiming Yang🇺🇸

    Heterogeneous nucleation is central to many familiar first-order phase transitions such as the freezing of water and the solidification of metals, and it can also play a crucial role in cosmology. We examine nucleation seeded by preexisting domain walls and demonstrate its strong impact on the dynamics of cosmological phase transitions. The bubble solutions take the form of spherical caps, and the contact angle is fixed by the ratio of the domain-wall tension to the bubble-wall tension. A larger domain-wall tension, or equivalently a smaller contact angle, reduces the wall-seeded bubble volume and lowers the critical nucleation action. For theories with ${\mathbb{Z}}_{n\ge 3}$ symmetry, domain-wall junctions naturally appear and we find that they seed nucleation even more efficiently than the walls themselves. Using a two-scalar-field model as an illustration, we compute nucleation temperatures for both homogeneous and heterogeneous channels and show that junction-seeded nucleation occurs at a higher temperature and is the dominant mechanism that completes the first-order cosmological phase transition.

    hep-phastro-ph.COJCAP(2026)·5 citations
26. 26*

    Spontaneous baryosynthesis with large initial phase

    Maxim Krasnov🇷🇺 · Maxim Khlopov🇫🇷 · Ufuk Aydemir

    We numerically investigate particle production by a pseudo-Nambu-Goldstone boson (pNGB) in spontaneous baryogenesis, focusing on large initial misalignment angles. Our analysis confirms the established cubic dependence of the baryon asymmetry on the initial phase for small angles. However, this scaling breaks down for larger angles, with particle production saturating as the initial phase approaches $\pi$ in Minkowski spacetime.

    hep-phhep-thBled Workshops Phys. 26, no. 1, 175-184 (…·0 citations
27. 27*

    Constraints on light QCD and CP-violating axions from the death line of rotation-powered pulsars

    Samuel J. Witte🇬🇧 · Andrea Caputo🇨🇭 · Stefan Stelzl🇨🇭 · Alexander Chernoglazov🇺🇸 · Alexander A. Philippov🇺🇸 · Surjeet Rajendran🇺🇸

    Dense nuclear matter can modify the effective potential of axions, displacing them from their vacuum minimum, and sourcing large external field gradients (``axion hair"). In the case of neutron stars, axion hair directly modifies the electrodynamic processes operating on the open field-line region, strongly enhancing or suppressing the acceleration experienced by ambient charges. As a result, the point in the neutron star lifetime at which pair-cascades cease -- known as pulsar ``death" -- can be dramatically altered, allowing for much older pulsars to emit observable radio emission. We study the pair discharge process in the presence of axion hair using semi-analytic techniques and particle-in-cell simulations, and use these results alongside pulsar demographics to derive new constraints on light QCD axions with non-negligible axion-photon coupling and CP-violating axion-nucleon interactions. We also illustrate how nearly orthogonal rotators, where emission is observed from both poles (such as in the case of PSR J1906+0746), provides a complementary probe of axion hair.

    hep-phastro-ph.HE6 citations
28. 28*

    Weak Scale Triggers in the SMEFT

    Pier Giuseppe Catinari🇮🇹 · Raffaele Tito D'Agnolo🇫🇷 · Pablo Sesma🇫🇷

    There are no weak scale triggers in the SMEFT up to dimension six that can solve the hierarchy problem far above the weak scale. Our arguments can be used to show that the same is true at dimension eight. Weak scale triggers are local operators sensitive to the Higgs mass squared and they are needed in a large number of qualitatively different cosmological solutions to the hierarchy problem. These solutions have little in common besides the use of a trigger operator. We argue that focusing on the signatures of the three already-known trigger operators can lead to discover or exclude this class of solutions to the hierarchy problem.

    hep-phhep-thJHEP(2026)·1 citation
29. 29*

    Dedicated Searches for Millicharged Particles at Intensity-Frontier Facilities: SpinQuest and SHiP

    Leo Bailloeul🇺🇸 · Matthew Citron🇺🇸 · Yanou Cui🇺🇸 · Saeid Foroughi-Abari🇨🇦 · Insung Hwang🇺🇸 · Fengyi Li🇺🇸 · Yu-Dai Tsai🇺🇸 · Ming Xiong Liu🇺🇸 · Kranti Gunthoti🇺🇸 · Jae Hyeok Yoo🇰🇷

    We conduct a dedicated study of searches for millicharged particles (mCPs) utilizing scintillator-based detectors at high-intensity fixed-target experiments, with particular focus on the SpinQuest and forthcoming Search for Hidden Particles experiment (SHiP) facilities. The analysis incorporates the three primary production mechanisms: meson decays, Drell-Yan processes, and proton bremsstrahlung. In particular, our updated analysis reveals that proton bremsstrahlung dominates the production rate in the sub-GeV mass regime. Detailed detector simulations and background evaluations are performed to obtain realistic sensitivity estimates. Our results demonstrate that future experiments located in the SpinQuest and SHiP facilities can achieve substantial improvements in discovery potential, enhancing sensitivity to the mCP charge parameter $ϵ=q_{\chi }/e$ (with $q_{\chi }$ denoting the mCP electric charge) by up to two orders of magnitude relative to existing limits.

    hep-ph4 citations
30. 30*

    Amplitude Surrogates for Multi-Jet Processes

    Luca Beccatini🇧🇪 · Fabio Maltoni🇧🇪 · Olivier Mattelaer🇧🇪 · Ramon Winterhalder🇮🇹

    Accurate and efficient amplitude predictions are essential for precision studies of multi-jet processes at the LHC. We introduce a novel neural network architecture that predicts multi-jet amplitudes by leveraging the Catani-Seymour factorization scheme and related lower-jet amplitudes, requiring the network to learn only a correction factor. This hybrid approach combines theoretical factorization with a data-driven ansatz, enabling fast and scalable amplitude predictions. Our networks also estimate the accuracy of each prediction, allowing us to selectively use results that meet a predefined accuracy threshold. In the context of leading-order event generation, this approach achieves speed-up factors of up to 20 while maintaining all observables at the percent-level accuracy.

    hep-phSciPost Phys.(2026)·15 citations
31. 31*

    Dynamical study of hidden-strange pentaquarks as analogs of the hidden-charm states

    Xuejie Liu🇨🇳 · Yue Tan🇨🇳 · Yuheng Wu🇨🇳 · Dianyong Chen🇨🇳 · Hongxia Huang🇨🇳 · Jialun Ping🇨🇳

    Motivated by the recent BESIII experiment~\cite{BESIII:2024muk} searching for hidden-strange exotic hadrons, we perform a systematic theoretical study of the hidden-strange pentaquark system within the framework of the quark delocalization color screening model (QDCSM) and the resonating group method (RGM). Our results demonstrate that the channel coupling effect plays a decisive role in the formation of bound and resonance states. It not only significantly enhances the short-range attraction but also induces essential attractive contributions from pion exchange. We predict three bound states with masses of $1759$ MeV, $2000$ MeV, and $2407$ MeV. Furthermore, we report the existence of a hidden-strange pentaquark resonance state, $\Xi K^{\ast }$, with quantum numbers $I(J^P)=0(1/2^{-})$. This resonance is identified in the $S$-wave scattering phase shifts of the $\Lambda {\eta }_s$ and $\Lambda \varphi$ open channels, with a predicted mass in the range of $2204\text{–}2208$ MeV. By accounting for both the scattering width from channel coupling and the intrinsic decay width of the constituent $K^{\ast }$, the total decay width is estimated to be $55\text{–}63$ MeV. These theoretical predictions provide important guidance for future experimental searches for such exotic states at facilities like BESIII.

    hep-phnucl-thEPJC(2026)·1 citation
32. 32*

    Dynamical correlations across momentum scales in the Quark-Gluon Plasma

    Lipei Du🇺🇸 · P. M. Jacobs🇺🇸

    Experimental probes of the Quark-Gluon Plasma (QGP) generated in heavy-ion collisions span a broad range in momentum scale: low transverse momentum (low $p_T$) measurements probe collective dynamics, while high $p_T$ measurements probe the response to QGP excitation by jets (jet quenching). However, the dynamical interplay between QGP collective dynamics and jet quenching is currently poorly understood. We present a new framework for exploring dynamical correlations across momentum scales in heavy-ion collisions, based on the $p_T$-differential radial-flow observable $v_0(p_T)$. Measured $v_0(p_T)$ phenomenology is traced to the evolution in strength and coherence of distinct underlying fluctuation modes. We then propose new experimental observables to quantify this evolution. The eigenvalue ratio ${\lambda }_2/{\lambda }_1$ of the reference-aligned covariance matrix $V_0$ is shown to measure the effective fluctuation rank, while the $p_T$-dependence of the corresponding eigenvectors maps the evolution from a single coherent soft mode to multi-mode dynamics including coalescence and jet quenching. These observables map the soft-mid-hard correlation structure and provide a unified description of the collective-to-partonic transition in the QGP.

    ↳ nucl-thhep-phnucl-exPLB(2026)·2 citations
33. 33*

    5D Rotating Black Holes as dark matter in Dark Dimension Scenario: Hawking Radiation versus the Memory Burden Effect

    George K. Leontaris🇬🇷 · George Prampromis🇬🇷

    This work explores the possibility that five-dimensional primordial rotating black holes could account for all, or a significant portion, of the dark matter in our universe. Our analysis is performed within the context of the ``dark dimension'' scenario, a theoretical consequence of the Swampland Program that predicts a single micron-scale extra dimension to explain the observed value of dark energy. We demonstrate that within this scenario, the mass loss of a primordial rotating black hole sensitive to the fifth dimension is significantly slower than that of its four-dimensional counterpart. Consequently, primordial black holes with an initial mass of $M\gtrsim 10^{10}$g can survive to the present day and potentially constitute the dominant form of dark matter. Finally, we investigate the memory burden effect and find that it dramatically prolongs the lifetime of five-dimensional rotating primordial black holes, making them compelling candidates for all the dark matter in the universe.

    ↳ hep-thgr-qchep-phJCAP(2026)·6 citations
34. 34*

    Nonlinear evolution of the ergoregion instability: Turbulence, bursts of radiation, and black hole formation

    Nils Siemonsen🇺🇸 · William E. East🇨🇦

    Spacetimes with an ergoregion that is not connected to a horizon are linearly unstable. While the linear regime has been studied in a number of settings, little is known about the nonlinear evolution of this ergoregion instability. Here, we investigate this by numerically evolving the unstable growth of a massless vector field in a rapidly spinning boson star in full general relativity. We find that the backreaction of the instability causes the star to become more gravitationally bound, accelerating the growth, and eventually leading to black hole formation. During the nonlinear growth phase, small scale features develop in the unstable mode and emitted radiation as nonlinear gravitational interactions mediate a direct turbulent cascade. The gravitational wave signal exhibits bursts, akin to so-called gravitational wave echoes, with increasing amplitude towards black hole formation.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2026)·4 citations
35. 35*

    Application of time-series analysis methods to a multiple-sector TESS observations: the case of the radio-loud blazar 3C 371

    Ashutosh Tripathi🇨🇳 · Paul J. Wiita🇺🇸 · Ryne Dingler🇺🇸 · Krista Lynne Smith🇺🇸 · R. A. Phillipson🇺🇸 · Matthew J. Graham🇺🇸 · Lang Cui🇨🇳

    We present various time series analysis methods to analyze multiple-sector observations of bright AGN from the Transiting Exoplanet Survey Satellite (TESS) and examine whether issues such as gaps and noise in these data can be mitigated. We determine variability timescales and search for quasi-periodicity using these methods and assess any differences. In this paper, we present an analysis of the $\approx$300-day TESS observation of a blazar 3C 371 using power spectrum density, structure-function, and weighted wavelet Z-transform approaches. To reduce the effect of gaps and noise, Continuous auto-regressive moving averages, Bartlett periodogram, and wavelet decomposition methods are used. We have also used recurrence analysis to account for the nonlinearity present in the data and to quantify variability or periodicity as the recurrent state. Considering the entirety of the TESS observations, we derive the variability timescale to be around 4.5 days. Sector-wise analysis found variability timescales in the range of 3.0--7.0 days, values that are found to be consistent using different methods. When analyzing multiple sectors together, significant variability, which could be quasi-periodic oscillations (QPOs), of duration 3--6 days in individual segments, is detected. These may be attributed to the kink instabilities developed in the jet or the existence of mini-jets inside a jet undergoing precession. We find that these methods, when applied appropriately, can be used to study the variability in TESS data. The noise present in these TESS observations can be minimized using Bartlett's periodogram and wavelet decomposition to recover the real stochastic variability.

    ↳ astro-ph.HEhep-phMNRAS(2025)·3 citations
36. 36*

    Bound-free electron-positron pair production in combined Coulomb and constant crossed electromagnetic fields: a Schwinger-like process with intrinsic assistance

    S. Remme🇩🇪 · A. Eckey🇩🇪 · S. Villalba-Chávez🇩🇪 · A. B. Voitkiv🇩🇪 · C. Müller🇩🇪

    The bound-free channel of electron-positron pair production by a highly charged bare ion in the presence of a strong constant crossed electromagnetic field is studied. To calculate the pair production rate, two different methods are applied and compared with each other: (i) a quasiclassical tunneling theory and (ii) a strong-field approximation, both equipped with appropriate Coulomb correction factors. The resulting rate, which depends nonperturbatively on both the Coulomb field of the ion and the constant crossed field, is calculated in a broad range of applied field strengths and nuclear charge numbers. Its functional form resembles the rate for a dynamically assisted Schwinger-like process, with the assistance being provided by the atomic binding energy of the created electron.

    ↳ physics.atom-phhep-phPRA(2026)·2 citations
37. 37*

    Two-Dimensional Pulsar Distance Inference from Nanohertz Gravitational Waves

    Si-Ren Xiao🇺🇸 · Ji-Yu Song🇺🇸 · Yue Shao🇺🇸 · Ling-Feng Wang🇨🇳 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    Pulsar timing arrays (PTAs) are limited in localizing nanohertz continuous gravitational waves (CGWs) by uncertainties in pulsar distances. We introduce a method to infer pulsar distances in two dimensions, using phase information from the pulsar terms of multiple CGW sources. Our approach can enhance distance precision and, in some cases, achieve order-of-magnitude improvements relative to existing one-dimensional distance-inference methods. Using simulations of an SKA-era PTA with realistic parallax-based distance priors, we demonstrate that pulsars at $\sim 1$ kpc can achieve sub-parsec distance precision with only a few CGW sources. Such improvements in pulsar-distance precision have important implications for CGW host-galaxy identification and multimessenger observational prospects.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph8 citations
38. 38*

    Phase structure of the one-dimensional ${\mathbb{Z}}_2$ lattice gauge theory with second nearest-neighbor interactions

    Yeimer Zambrano🇵🇱 · Aleksey Alekseev🇵🇱 · Konrad J. Kapcia🇵🇱 · Krzysztof Cichy🇵🇱 · Agnieszka Cichy🇵🇱

    We investigate the ground-state phase diagram of a one-dimensional ${\mathbb{Z}}_2$ lattice gauge theory (LGT) model with hard-core bosons at half-filling, extending previous studies by including second nearest-neighbor (2NN) interactions. Using matrix product state techniques within the density matrix renormalization group, we compute charge gap, static structure factor, pair-pair correlation functions, and entanglement entropy for various interaction strengths and field parameters. We analyze two representative neatest-neighbor interaction strengths ($V_1$) that correspond to the Luttinger liquid (LL) and Mott insulator (MI) phases in the absence of the 2NN interactions. We introduce the 2NN coupling $V_2$ and investigate its impact on the system. Our results reveal very rich behavior. As the 2NN repulsion increases, in the case of small $V_1$, we observe a direct transition from the LL phase to a charge-ordered insulator (COI) phase with four-site ordering pattern, whereas for large $V_1$, we observe a transition from the MI phase with two-site ordering pattern (previously found with only $V_1$ included), going through an intermediate LL region, and finally reaching the COI regime. Additionally, the inclusion of 2NN interactions enhances charge order and suppresses pair coherence, evidenced by sharp peaks in the structure factor and rapid decay in pair-pair correlators. Our work extends the well-studied phase structure of 1D ${\mathbb{Z}}_2$ LGT models and demonstrates the interplay between gauge fields, confinement, and extended interactions.

    ↳ cond-mat.str-elhep-lathep-phphysics.comp-ph+1PRB(2026)·0 citations
39. 39*

    Equation of state, QCD phase diagram: predictions from lattice QCD

    Bastian B. Brandt🇩🇪

    I review recent results on phase structure and equation of state of strong interaction matter from lattice QCD. Particular emphasis is given to the axes where direct simulations are possible and results are obtained with sufficient control over systematic effects. I also discuss the status of approaching the region of non-zero baryochemical potentials using indirect methods.

    ↳ hep-lathep-exhep-phhep-th+1EPJ Web Conf.(2026)·1 citation
40. 40*

    Conformal collider bootstrap in $\mathcal{N}=4$ SYM

    Ross Dempsey🇺🇸 · Robin Karlsson🇬🇧 · Silviu S. Pufu🇺🇸 · Zahra Zahraee🇨🇦 · Alexander Zhiboedov🇨🇭

    We use a combination of perturbation theory, holography, supersymmetric localization, integrability, and numerical conformal bootstrap methods to constrain the energy-energy correlator in $\text{SU}(N_c)$ $\mathcal{N}=4$ SYM at finite coupling. For finite $N_c$, we derive lower bounds on the second and fourth multipoles of the energy-energy correlator at different couplings, along with a smeared energy-energy correlator as a function of the angle between the two detectors. We present evidence that our lower bounds on the multipoles are nearly saturated by the $\mathcal{N}=4$ SYM theory. In the planar limit, we further use dispersive functionals to obtain tight two-sided bounds on both the first three non-trivial multipoles and on the angular dependence of the energy-energy correlator. As the coupling is varied from weak to strong, the energy-energy correlator exhibits a transition from single-trace to double-trace operator dominance in the collinear limit, which we characterize quantitatively. A similar phenomenon occurs in QCD, where a parton-hadron transition is observed as detectors are brought closer together.

    ↳ hep-thhep-ph12 citations
41. 41*

    Measuring the neutron star equation of state from EMRIs in dark matter environments with LISA

    Theophanes K. Karydas🇳🇱 · Gianfranco Bertone🇳🇱

    Gravitational-wave observations of extreme mass-ratio inspirals (EMRIs) in vacuum are largely insensitive to the internal structure of the small compact companion. We show that this conclusion can change when the central black hole is surrounded by a dense dark matter environment. We compute, for the first time, the relativistic dynamical-friction force on a neutron star moving through a collisionless medium and its impact on the evolution of EMRIs embedded in dense dark matter spikes. We then perform a Bayesian parameter-estimation analysis of simulated LISA observations to assess the measurability of both spike properties and the companion's internal structure. We find that, in our fiducial dark matter spike models, EMRIs with signal-to-noise ratio (SNR) $\gtrsim 20$ already allow us to distinguish neutron star from black hole companions, while events with SNR $\gtrsim 400$ make it possible to discriminate between different neutron star equations of state.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phPRD(2026)·4 citations
42. 42*

    Structure of Chern-Simons Graviton Scattering Amplitudes from Topological Graviton Equivalence Theorem and Double Copy

    Hong-Xu Liu🇨🇳 · Zi-Xuan Yi🇨🇳 · Hong-Jian He🇨🇳

    Gravitons naturally acquire topological masses in the 3d topologically massive gravity (TMG) theory that includes the gravitational Chern-Simons term. We present a Weyl-transformed TMG (WTMG) formulation by introducing an unphysical dilaton field through the Weyl transformation. We perform the BRST quantization of the WTMG, which reduces to the conventional TMG in the unitary gauge. We demonstrate that this WTMG theory conserves the physical degrees of freedom (DoF) in the massless limit, under which the physical massive graviton becomes an unphysical massless graviton and its physical DoF is converted to the massless dilaton. With these, we newly establish a Topological Graviton Equivalence Theorem (TGRET), which connects each scattering amplitude of physical gravitons to the corresponding dilaton scattering amplitude in the high energy limit. The TGRET provides a general mechanism to guarantee all the large energy cancellations in any massive graviton scattering amplitudes. Applying the TGRET and using the generalized gravitational power counting rule, we prove that the $N$-point massive graviton amplitudes ($N\geqq 4$) have striking energy cancellations by powers proportional to $\frac{5}{2}N$ ($\frac{7}{2}N$) in the Landau (unitary) gauge. For four graviton scattering amplitudes, this explains their large energy cancellations of $E^{11}\to E^1$ (Landau gauge) and $E^{12}\to E^1$ (unitary gauge). We compute the four-point graviton (dilaton) amplitudes and explicitly demonstrate the TGRET and these large energy cancellations. With the extended massive double-copy approach, we systematically construct the three- and four-point graviton (dilaton) scattering amplitudes in the WTMG theory from the corresponding gauge boson (adjoint scalar) amplitudes in the topologically massive Yang-Mills theory.

    ↳ hep-thgr-qchep-ph0 citations
43. 43*

    Weak Gravity Conjecture in the sky: gravitational waves from preheating in Einstein-Maxwell-Scalar EFT

    Jiaxin Cheng🇨🇳 · Anna Tokareva🇨🇳

    The effective field theory (EFT) concept provides a necessary tool for obtaining general predictions of low-energy theory valid below its unitarity-breaking scale (cutoff scale). Early Universe inflation and subsequent reheating could be a unique setup for testing potentially observable effects coming from the derivative expansion of the corresponding EFT around the flat space vacuum. In this work, we consider an EFT describing perturbative reheating dominated by the decay of inflaton to photons caused by the dimension-5 operator $\varphi F_{\mu \nu }{F}^{\mu \nu }$. We compute the graviton production during reheating and high frequency gravitational wave signal due to the bremsstrahlung effect in the presence of $R_{\mu \nu \lambda \rho }{F}^{\mu \nu }{F}^{\lambda \rho }$ operator. It may lead to the dominant contribution at high momenta if the EFT cutoff is lower than the Planck mass. Assuming the general consequences of the unitarity and causality constraints, which imply that all EFT operators should be present, and be suppressed by the scales following from the dimension analysis, we obtain the observational constraints (CMB bound for the dark radiation) on the mass of the inflaton and UV cutoff of gravity. We find that for the typical parameters of large field inflation models, the gravitational cutoff scale cannot be lower than $10^{15}$ GeV.

    ↳ hep-thgr-qchep-ph3 citations
44. 44*

    Updated and Projected Cosmic Microwave Background Bounds on WIMP Annihilation

    Charlotte Myers🇺🇸 · Dominic Agius🇪🇸 · Daniele Gaggero🇮🇹 · Angelo Ricciardone🇮🇹

    We derive updated Cosmic Microwave Background (CMB) constraints on annihilating dark matter, and present forecasts for upcoming CMB surveys. We show that the addition of recent temperature, polarization, and lensing data from ground-based experiments yields only minor improvements ($\approx 10\%$) compared to Planck bounds, confirming that the sensitivity remains dominated by the large-scale E-mode polarization. Forecasts, using a LiteBIRD-like setup, indicate that pairing a low-noise, wide-sky satellite at $\ell <200$ with high-resolution ground observations nearly saturates the cosmic-variance limit, improving bounds by $\approx 60\%$, where our derived 95th percentile limit is $p_{\mathrm{ann}}<1.27\times 10^{-28}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}\mathrm{Ge}{\mathrm{V}}^{-1}$. We also consider the inclusion of B-mode polarization for a realistic future experiment.

    ↳ astro-ph.COhep-phPRD(2026)·2 citations
45. 45*

    Imprint of the black hole interior on thermal four-point correlators

    Joydeep Chakravarty🇨🇦

    We consider correlators smeared against directed wavepackets over a thermal state dual to a single-sided planar AdS black hole. In the large frequency limit, our measurement is simplified using a bulk WKB description. We propose a dictionary that maps the action of smeared boundary operators to flat-space oscillators near an interior bulk point on the thermal state, by analytically continuing late-time operators from the right to the left boundary via an integral transform. Using the dictionary the smeared correlator factorizes to a flat-space like scattering amplitude about the interior event. Our transformed correlators describe local physics in the two-sided black hole interior, while incurring a suppression of $\mathcal{O}(e^{-\beta \omega /2})$. These measurements necessitate a non-trivial time ordering of operators living on boundary hyperboloids which are causally connected to the past light cone of the bulk point, as well as on a corresponding future branch.

    ↳ hep-thgr-qchep-ph7 citations
46. 46*

    Detection prospects for heavy WIMP dark matter near supermassive black holes, particularly in M31

    Andrei E. Egorov🇷🇸

    This work analyzes the detection prospects for weakly interacting massive particles (WIMPs) in dark matter (DM) density spikes around nearby supermassive black holes (SMBHs) by observations in very high energy gamma-ray band. Such spikes are unique targets, which provide a possibility to discover the basic thermal s-wave annihilating WIMP with any mass up to the theoretical unitarity limit ~ 100 TeV. All relevant SMBHs were checked, and only MW* and M31* were identified as worthwhile objects. Cherenkov Telescope Array (CTA) sensitivity to heavy WIMPs in M31* was estimated. It was obtained that CTA will be able to probe a major part of TeV-scale WIMP parameter space in case of optimistic spike density configuration in M31*. In certain scenarios, M31* may yield even stronger constraints than MW*. Relevant systematic uncertainties were explored.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2026)·1 citation
47. 47*

    Geometry of non-Gaussianity in transient non-attractor inflation

    Mohammad Hossein Namjoo🇮🇷 · Bahar Nikbakht🇮🇷

    Inflationary models predicting abundant primordial black holes (PBHs) and large amplitude of scalar-induced gravitational waves (SIGWs) often rely on amplified fluctuations over limited scales, typically driven by phase transitions, particle production, or departures from slow-roll evolution. While the power spectrum of these models has been extensively studied, higher-order correlations are much less understood. Motivated by the complex physics involved and the fact that PBH and SIGW formation are both sensitive to non-linearities, we present a detailed study of the bispectrum as the leading non-linear effect in these scenarios. We refer to the scale- and shape-dependence of the bispectrum collectively as its geometry; and define a scale-dependent shape correlator to disentangle the two dependencies. Generally, we find that for the scales most affected by phase transitions and particle production (including the power spectrum peak), the bispectrum is strongest near the equilateral configuration, while non-attractor phases tend to produce correlations near the squeezed configuration. We further propose a simplified bispectrum estimator, resembling local-type non-Gaussianity but with scale-dependent amplitude, that captures the main features of the full bispectrum. As an implication of our results, we show that incorporating the bispectrum significantly broadens the range of scales with a substantial probability of large smoothed density contrasts compared to linear analysis. This suggests that non-linearities can alter not only PBH abundance and SIGW amplitude but also their mass and frequency spectra. In particular, and in contrast with the usual assumption, our results hint that the second-highest peak of the power spectrum may produce more PBHs than the highest peak.

    ↳ astro-ph.COgr-qchep-phhep-th5 citations
48. 48*

    Wet Hair: Global Symmetries in Entanglement Islands

    Hao Geng🇺🇸 · Jesús Huertas🇦🇷 · Andreas Karch🇺🇸 · Lisa Randall🇺🇸 · Dawson Thomas🇺🇸

    A central conjecture in quantum gravity is the non-existence of global symmetries. As a fully unitary theory, there is no information loss in a UV complete quantum gravity theory. We see both these concepts reflected in the AdS/CFT correspondence, which tells us that dynamical processes in AdS are fully captured by a manifestly unitary CFT with no information loss. Furthermore, global symmetries of the CFT are dual to gauge symmetries in the AdS, which implies no global symmetry in the AdS. In this work, we provide concrete evidence for the connection between the non-existence of global symmetries and the absence of information loss in quantum gravity. We study the $\text{island setups}$ in which a gravitational AdS is coupled with a nongravitational bath on its boundary. In such theories, the information in the AdS can be lost to the bath. We provide concrete examples with global symmetries in the island setup, from both the bottom-up and the top-down perspectives. We argue that these global symmetries are consistent due to $\text{entanglement islands}$, in which holography is realized in a novel fashion. The global symmetries we construct are all mixed with spontaneously broken gauge symmetries. We will show that this fact has two implications: $\text{1)}$ The black hole hair is detectable in the bath (``wet hair"); $\text{2)}$ a resolution of a puzzle proposed by Harlow and Shaghoulian.

    ↳ hep-thgr-qchep-ph8 citations
49. 49*

    Singularities in Cosmological Loop Correlators II : Non Local Interactions and Flat Space limits

    Elaf Ansari🇮🇳 · Supritha Bhowmick🇮🇳 · Diptimoy Ghosh🇮🇳

    Non-local interactions naturally arise in the ADM formalism after solving the constraint equations and substituting their solutions back into the action. However, the effects of these non-local operators on loop corrections to cosmological correlators remain largely unexplored. Extending the analysis of arXiv:2503.21880 , in this work we compute the $1$-loop bispectrum during slow-roll inflation, including the inverse-Laplacian operators present at cubic and quartic order in the ADM action (in the spatially flat gauge). These non-local vertices introduce non-trivial angular dependencies that significantly complicate the evaluation of loop integrals. We find that the diagrammatic rules of arXiv:2503.21880 for identifying poles and branch cuts in correlators without explicit integration remain valid even in the presence of such non-local interactions. Finally, we derive the flat-space limit of the $1$-loop inflationary correlator and verify it with explicit examples, thereby establishing a direct correspondence between its leading total-energy singularities (${\omega }_T\to 0$) and the flat-space scattering amplitude.

    ↳ hep-thgr-qchep-phJHEP(2026)·5 citations
50. 50*

    Self-gravitating equilibrium with slow steady flow and its consistent form of entropy current

    Shuichi Yokoyama🇯🇵

    A relativistic self-gravitating equilibrium system with spherical symmetry as well as with steady energy flow is investigated perturbatively around the hydrostatic limit, where the radial component of the fluid velocity field $u^{\mu }$ is sufficiently small. Each component of vectors and tensors consisting of the system is expanded in different powers, which makes the covariant perturbation approach ineffective. The differential equations to determine the subleading correction of the structure variables are presented. The system retains the current $j^{\mu }$ accounting for the steady flow, which contributes to the entropy current $s^{\mu }$ in such a general covariant form that $s^{\mu }=a{u}^{\mu }+b{j}^{\mu }$ with $a,b$ unknown parametric functions. To determine them, a new condition is proposed. This condition imposes the entropy current to be of an unconventional form $s^{\mu }=(s-b{j}^0)u^{\mu }/u^0+b{j}^{\mu }$, where $s$ is the entropy density. The remaining parameter $b$ is fixed by the current conservation equation. The perturbative analysis shows that $b$ starts with the quadratic order and its leading term is determined explicitly.

    ↳ gr-qcastro-ph.SRhep-phhep-thPLB(2026)·0 citations

* 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.