Tue·Mar 10, 2026Tuesday·March 10, 2026

1. 01*

   Lepton Mixing from a Lattice Flavon Model: A Two-Branch Octant-delta Prediction

   Vernon Barger🇺🇸

   We extend the single-flavon $B$-lattice Froggatt--Nielsen (FN) framework, previously successful for quark masses and Cabibbo-Kobayashi-Maskawa (CKM) mixing, to the lepton sector. The same $B$-lattice power structure ($ϵ\equiv 1/B\simeq 0.19$) generates charged-lepton mass hierarchies and a normal-ordered neutrino spectrum; large neutrino mixing angles require an additional approximate $Z_2$ mu--tau reflection symmetry, broken at $\mathcal{O}(ϵ)$ to generate a nonzero reactor angle and CP-violating phase. The PMNS matrix factorizes as $U_{\mathrm{PMNS}}=U_e^{†}{U}_{\nu }$, with near-tribimaximal $U_{\nu }$ corrected by small charged-lepton rotations whose phases are aligned by the single-flavon origin of the Yukawa textures. A single interference relation expresses the observed Dirac phase $\delta$ as the neutrino-sector phase ${\delta }_{\nu }$ shifted by a calculable charged-lepton correction, and correlates the sign of that shift with the atmospheric octant; this produces a two-branch prediction in the $({\theta }_{23},\delta )$ plane: a lower-octant solution with ${\theta }_{23}\approx 43^{\circ }$, $\delta \approx 286^{\circ }$, and an upper-octant solution with ${\theta }_{23}\approx 46^{\circ }$, $\delta \approx 299^{\circ }$. This structure has a geometric form as a ${\nu }_3$-column normalization triangle whose base angle is $2{\theta }_{23}$, with maximal mixing the $90^{\circ }$ limit and the octant fixed by the side of $90^{\circ }$ on which the base angle falls. The lower octant is mildly favored, by a margin that depends on the coefficient prior. Both branches place the Dirac phase above $270^{\circ }$, i.e. near-maximal leptonic CP violation, favored by T2K. The Jarlskog invariant $J_{\mathrm{CP}}\simeq -0.03$ is nearly branch-independent; only precision measurements of the atmospheric octant and Dirac phase at DUNE, Hyper-Kamiokande, IceCube, and JUNO can distinguish the two solutions.

   hep-phhep-ex4 citations
2. 02*

   Vacuum Birefringence, Ellipticity, and the Anomalous Magnetic Moment of a Photon

   Sree Ram Valluri🇨🇦 · Farrukh Chishtie🇨🇦 · Wieslaw J. Mielniczuk

   We study photon propagation in a strong magnetic field $B\sim B_{\mathrm{cr}}$, where $B_{\mathrm{cr}}=\frac{m^2}{e}\simeq 4.4\times 10^{13}$ Gauss is the Schwinger critical field. We show that the expected value of the Hamiltonian of a quantized photon for a perpendicular mode is a convex function of the magnetic field $B$. We find that the anomalous magnetic moment of a photon in the one-loop approximation is a non-decreasing function of the magnetic field $B$ in the range $0\le B\le 30B_{\mathrm{cr}}$. We find that the anomalous magnetic moment ${\mu }_{\gamma }$ of a photon for $B=30B_{\mathrm{cr}}$ is $\sim 8/3$ of the anomalous magnetic moment of a photon for $B=1/2B_{\mathrm{cr}}$. We establish new connections between ${\mu }_{\gamma }$, vacuum birefringence, and directly measurable polarization observables. Based on recent experimental observations -- including the ATLAS detection of light-by-light scattering at $8.2\sigma$ significance, IXPE X-ray polarimetry of magnetars revealing polarization degrees up to 80\%, and continuing PVLAS measurements approaching QED sensitivity -- we provide predictions for ellipticity and polarization degree as important observables for future experiments. Numerical verification of our analytical results confirms the theoretical predictions with high precision.

   hep-phhep-th1 citation
3. 03*

   Conformal versus non-conformal two-Higgs-doublet model: phase transitions and gravitational waves

   Nico Benincasa🇨🇳 · Ji-Wei Li🇨🇳 · Hanxiao Pu🇨🇦 · Robert B. Mann🇨🇦 · Vahid Shokrollahic🇨🇦 · T.G. Steele🇨🇦 · Zhi-Wei Wang🇨🇳

   In this work we investigate the CP-conserving two-Higgs-doublet model (2HDM) in two realizations: a classically conformal setup (C2HDM) and a non-conformal setup with explicit tree-level quadratic mass terms (NC2HDM). Imposing current theoretical and experimental constraints, we scan the parameter space and analyse the electroweak first-order phase-transition dynamics from the finite-temperature effective potential, determining the relevant thermodynamic scales and the associated parameters $\alpha$ and $\beta /H_{\ast }$. In the resulting $(\alpha ,\beta /H_{\ast })$ phase diagrams, the NC2HDM spans a substantially broader region and hosts the strongest transitions, whereas the C2HDM is confined to a nested, weaker-transition subset. This challenges the common expectation that classical conformal symmetry generically implies deep supercooling. By relaxing the Higgs-mass identification and varying the scalon mass, we show that sizable supercooling is obtained only when the radiative (one-loop) breaking of scale invariance is sufficiently mild, i.e. for a light scalon. We then compute the resulting stochastic gravitational-wave spectra and show that only the NC2HDM yields benchmark points potentially observable by future space-based interferometers such as LISA, TianQin and Taiji (and, in favourable cases, by more sensitive missions such as DECIGO/BBO).

   hep-ph3 citations
4. 04*

   Alternative framework for the left-right symmetric model including vector-like fermions

   Yassine Bouzeraib🇩🇿 · Mohamed Sadek Zidi🇩🇿

   We extend the left-right symmetric model with an additional non-abelian $SU(2)$ gauge symmetry. The particle content is augmented by one generation of vector-like fermions transforming under the fundamental representation of this new gauge group. Consequently, new self-dual scalar fields have been introduced for the sake of breaking the symmetry and invoking the mixing of vector-like fermions with the chiral fermions. This model explains the smallness of the neutrinos masses, showing that the 1rst and 2nd generation neutrinos masses are governed by the seesaw relation of the LRSM, while the 3rd generation neutrino mass is controlled by a new seesaw relation which involves the VLN. We investigated the production of a resonant extra charged gauge boson which decays into vector-like quarks in association with 3rd generation or into heavy Majorana neutrinos. We exploited the {\tt run II} LHC data to set lower limits on the mass of $W^{\prime }$, and consequentially on the $Z^{\prime }$. We find that the most restrictive constraints come from the decay of the $W^{\prime }$ to the 2nd generation heavy Majorana neutrinos. We also examine the single production of the top vector-like quark with $t$ and $b$ quarks, where parton-shower is taken into account.

   hep-phJHEP(2026)·1 citation
5. 05*

   Impact of chirality imbalance and nonlocal interactions on the QCD biased axionic domainwall interpretation of NANOGrav 15 year data

   Ruotong Zhao🇨🇳 · Zhao Zhang🇨🇳

   We investigate the influence of the chirality imbalance with local CP-breaking in hot QCD on the generation of a stochastic gravitational wave background (SGWB) sourced by the axion-like particle (ALP) domain-wall annihilation, induced by the QCD bias. Such a bias is quantified by the QCD topological susceptibility ${\chi }_t$, and its dependence on the $\theta$ angle and the chiral chemical potential ${\mu }_5$ is investigated at temperatures near the QCD scale within a nonlocal Nambu-Jona-Lasinio (NJL) model. We find that, besides the small-$\theta$ range, the axionic domain-wall interpretation of NANOGrav 15-year data on the nHz gravitational waves is still possible for a certain large-$\theta$ range if ${\mu }_5$ is large enough. We confirm that the peak of $|{\chi }_t|$ at the critical temperature $T_c$ for the CP restoration at $\theta =\pi$ exhibits a pronounced width compared to the local NJL result. Thus, for $\theta$ at and around $\pi$, the QCD bias near $T_c$ can also produce a GW signal strength compatible with the NANOGrav 15-year data.

   hep-ph0 citations
6. 06*

   Schwinger effect in QCD and nuclear physics

   Hidetoshi Taya🇯🇵

   We provide a pedagogical review of the Schwinger effect, i.e., the non-perturbative production of particle and anti-particle pairs from the vacuum by strong fields, as well as related strong-field phenomena. Beginning with an overview of the Schwinger effect in quantum electrodynamics, we discuss its extensions to quantum chromodynamics and its applications in nuclear physics, including high-$Z$ nuclei, string breaking, relativistic heavy-ion collisions, and the chiral anomaly.

   hep-phhep-thnucl-thphysics.plasm-ph2 citations
7. 07*

   Physics-Informed Global Extraction of the Universal Small-$x$ Dipole Amplitude

   Si-Wei Dai🇨🇳 · Fu-Peng Li🇨🇳 · Long-Gang Pang🇨🇳 · Guang-You Qin🇨🇳 · Shu-Yi Wei🇨🇳 · Han-Zhong Zhang🇨🇳 · Wenbin Zhao🇨🇳

   We extract the universal small-$x$ dipole scattering amplitude $N(r,x_B)$ from a global analysis based on a physics-informed neural network (PINN), without imposing a priori MV-type parametrization of the initial condition. The network provides a smooth and differentiable surrogate for $N(r,x_B)$, whose rapidity dependence is constrained by the collinearly improved Balitsky--Kovchegov evolution equation, while its functional form is simultaneously constrained by Deep Inelastic Scattering (DIS) data for the reduced total and charm cross sections, exclusive $J/\psi$ photoproduction measurements, and a positivity requirement for the momentum-space dipole amplitude. The resulting single universal amplitude consistently describes all fitted observables within a unified framework, alleviating the long-standing tension between total and charm channels encountered in conventional small-$x$ fits based on rigid parametric ansätze. Within the fitted kinematic domain, the best extracted PINN solution yields a smooth, non-negative momentum-space dipole over the full transverse-momentum range examined. Our results provide a robust and well-behaved input for Color Glass Condensate phenomenology across a broad class of high-energy processes.

   hep-phhep-exnucl-exnucl-th8 citations
8. 08*

   Rephasing invariant structure of Dirac CP phase and basis independent reduction of unitarity constraints for mixing matrices

   Masaki J. S. Yang🇯🇵

   In this paper, we explore rephasing invariant structures of the Dirac CP phase $\delta$ under an approximation $U_{13}^e=0$, where the 1-3 element of the diagonalization of charged leptons $U^e$ is neglected. With the further simplified condition $U_{12}^e=0$, the Dirac phase reduces to a compact form $\delta ={\delta }^{\nu }+\arg [(U_{33}^e/U_{23}^e)-(U_{33}^{\nu }/U_{23}^{\nu })]-\arg [(U_{33}^e/U_{23}^e)+(U_{23}^{\nu \ast }/U_{33}^{\nu \ast })]$, and the CP phase for finite $U_{12}^e$ can be understood as a generalization of this compact form. These results encompass almost all perturbative calculations of the CP phases in quark and lepton mixing matrices with hierarchical masses of charged fermions, and are independent of any specific parametrization. As a second result of this work, we derive a basis independent reduction of the unitarity constraints for an arbitrary unitary matrix $V$ by eliminating the elements $V_{21},V_{22},V_{31},V_{32}$ using the inversion formula. Applying the explicit rephasing transformation to this reduction yields a rephasing invariant representation of the PDG parametrization, which allows the translation of theoretical results expressed in the PDG parametrization directly into rephasing invariants.

   hep-ph3 citations
9. 09*

   Heavy mesons with dynamical gluon on the light front

   Jiatong Wu🇨🇳 · Hengfei Zhao🇨🇳 · Kaiyu Fu🇨🇳 · Zhi Hu🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸

   We investigate the structure of charmonium, bottomonium, and ${\mathrm{B}}_{\mathrm{c}}$ meson systems within the Basis Light-Front Quantization (BLFQ) approach, including both the quark-antiquark ($|q\bar{q}⟩$) and quark-antiquark-gluon ($|q\bar{q}g⟩$) Fock sectors. Our input light-front Hamiltonian incorporates a confining potential inspired by light-front holography, as well as the quark-gluon interaction from Quantum Chromodynamics. By adjusting model parameters to reproduce the mass spectra for low-lying states, we obtain the light-front wave functions for the heavy meson states. Based on these wave functions, we calculate electromagnetic form factors, decay constants, parton distribution amplitudes (PDAs), and parton distribution functions (PDFs) of the quarks and gluons in the heavy mesons. Our results for the charge radii and decay constants reasonably agree with experimental data and other theoretical approaches. The PDAs are consistent with the predictions from the earlier BLFQ calculations with an effective one-gluon exchange interaction. Furthermore, we present the first predictions within the BLFQ framework for the gluon PDFs in heavy mesons based on the light-front wave function in the $|q\bar{q}g⟩$ sector.

   hep-phhep-thnucl-th2 citations
10. 10*

    Formalizing the stability of the two Higgs doublet model potential into Lean: identifying an error in the literature

    Joseph Tooby-Smith🇬🇧

    In 2006, using the best methods and techniques available at the time, Maniatis, von Manteuffel, Nachtmann and Nagel published a now widely cited paper on the stability of the two Higgs doublet model (2HDM) potential. Twenty years on, it is now easier to apply the process of formalization into an interactive theorem prover to this work thanks to projects like Mathlib and Physlib (the latter formerly PhysLean and Lean-QuantumInfo), and to ask for a higher standard of mathematical correctness. Doing so has revealed an error in the arguments of this 2006 paper, invalidating their main theorem on the stability of the 2HDM potential. This case is noteworthy because to the best of our knowledge it is the first non-trivial error in a physics paper found through formalization. It was one of the first papers where formalization was attempted, which raises the uncomfortable question of how many physics papers would not pass this higher level of scrutiny.

    hep-phcs.LOhep-th5 citations
11. 11*

    Probing the CP Property of ALP-photon Interactions at Future Lepton Colliders

    Jian-Nan Ding🇨🇳 · Yandong Liu🇨🇳 · Muyuan Song🇨🇳

    We investigate a charge-parity (CP) odd axion-like particle (ALP) featuring simultaneous CP-conserving ($a{F}_{\mu \nu }{\tilde{F}}^{\mu \nu }$) and CP-violating ($a{F}_{\mu \nu }{F}^{\mu \nu }$) ALP-photon interactions at future lepton colliders. The ALP signal is studied in the process $e^{+}{e}^{-}\to e^{+}{e}^{-}a\to e^{+}{e}^{-}\gamma \gamma$, where the CP structure of the interaction can be probed using the azimuthal angle difference between the final-state electrons, $\Delta {\varphi }_{ee}$. We show that the projected sensitivity to the ALP-photon couplings can reach $\mathcal{O}(10^{-3}){\mathrm{TeV}}^{-1}$, exceeding current constraints from the electron electric dipole moment ($e$EDM). Because purely CP-conserving, purely CP-violating, and mixed interactions generate distinct $\Delta {\varphi }_{ee}$ distributions, a binned likelihood analysis of this observable enables an efficient discrimination of the ALP interaction structure. In particular, if the CP-conserving and CP-violating couplings are comparable--as motivated by possible symmetry considerations--the interference pattern in the $\Delta {\varphi }_{ee}$ distribution allows future lepton colliders to identify CP violation in the ALP sector once a signal is observed. For scenarios where the two couplings differ significantly, increasing the integrated luminosity substantially improves the sensitivity to CP-violating effects.

    hep-ph0 citations
12. 12*

    Nonminimal Lorentz Violation in Atomic and Molecular Spectroscopy Experiments

    Arnaldo J. Vargas🇺🇸

    This presentation discusses potential signals of Lorentz violation that could be observed in atomic and molecular spectroscopy experiments. It provides a general overview of the nonrelativistic effective SME coefficients that have been constrained, as well as the prospects for placing first-time bounds on those that remain unconstrained. Additionally, it highlights the importance of considering transitions involving atomic or molecular states with high angular momentum in tests of Lorentz symmetry.

    hep-phphysics.atom-ph1 citation
13. 13*

    Connecting baryon light-front wave functions to quasi-transverse-momentum-dependent correlators in lattice QCD

    S. Rodini🇮🇹 · A. Schiavi🇮🇹 · B. Pasquini🇮🇹

    Within light-front quantization, hadrons can be represented on a Fock-space basis of configurations of elementary partons. The coefficients of the expansion are called light-front wave functions (LFWFs), and encode all the dynamical degrees of freedom. We show how to extract the LFWFs of baryons, such as the proton, from equal-time correlators suitable for Lattice QCD simulations. Using an operator product expansion, we prove the factorization of the relevant correlator in the three-quark color-singlet LFWF, a residual lattice factor, and a soft factor that systematically subtracts the additional divergences arising from the factorization. We verify up to next-to-leading order the independent renormalizability of the LFWF, and we derive the evolution equations that govern its scale dependence.

    hep-phhep-latnucl-thPRD(2026)·0 citations
14. 14*

    The Dark Photon: a 2026 Perspective

    Andrea Caputo🇨🇭 · Rouven Essig🇺🇸

    We give a pedagogical overview of dark photons. We describe the theory and their importance in particle physics research, and discuss searches using laboratory, astrophysical, and cosmological probes.

    hep-ph18 citations
15. 15*

    Precise Predictions for Hadronic Higgs Decays

    Elliot Fox🇬🇧

    The prospect of future electron-positron colliders operating as "Higgs factories" in a clean experimental environment presents one of the most promising avenues for Higgs precision measurements. In order to capitalise on this, we need to have good theoretical control over these observables. In this talk, I will report on recent calculations in Hadronic Higgs decays, focusing in particular on the variations between the dominant $H\to b\bar{b}$ channel via a Yukawa interaction, and the sub-dominant $H\to gg$ channel. Using the newly-developed "generalised antenna formalism", we have been able to calculate jet-rates and classical QCD event-shape observables up to NNLO accuracy, providing us with the means to quantify the differences between the two decay modes. For a subset of observables, we also match these NNLO results to NNLL resummation to obtain valid predictions even in the back-to-back limit.

    hep-ph0 citations
16. 16*

    Radiative corrections to the nucleon isovector $g_V$ and $g_A$

    Oleksandr Tomalak🇨🇳 · Yi-Bo Yang🇨🇳

    Electroweak, QCD, and QED radiative corrections to the nucleon low-energy coupling constants $g_V$ and $g_A$ are enhanced by large perturbative logarithms between the electroweak and hadronic scale, as well as between the hadronic scale and the low-energy MeV scale. Additionally, higher-order pion-mass splitting corrections to the nucleon axial-vector charge might be large. By consistently incorporating these effects, we provide an updated relation between the lattice-QCD and physical $g_A$, finding a total radiative correction of $3.5(2.1)\%$ ($5.6(0.7)\%$). This leads to an expected lattice-QCD result of $g_A^{\mathrm{QCD}}=1.265(26)$ ($g_A^{\mathrm{QCD}}=1.240(9)$) when based on a combination of lattice-QCD and data-driven (or only data-driven) inputs, respectively. Future phenomenological, chiral perturbation theory, and lattice-QCD studies can improve both the central value and the uncertainty of this estimate.

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

    Cobimaximal mixing pattern from a $\Delta (27)$ inverse seesaw model

    A. E. Cárcamo Hernández🇨🇱 · Ivo de Medeiros Varzielas🇵🇹 · Nicolás A. Pérez-Julve🇨🇱

    We present an inverse seesaw model based on the $\Delta (27)$ symmetry and Abelian discrete symmetries, which account for the mass hierarchies and, through a specific pattern of symmetry breaking, leads to viable leptonic mixing angles according to the cobimaximal mixing pattern. In the model, leptogenesis successfully accounts for the observed baryon asymmetry of the Universe for a large range of the parameter space, only for the scenario of normal neutrino mass hierarchy.

    hep-ph0 citations
18. 18*

    Flash from the Past: New Gamma-Ray Constraints on Light CP-even Scalar from SN1987A

    Yue Yu🇺🇸 · Writasree Maitra🇺🇸 · P. S. Bhupal Dev🇺🇸 · Jean-Franccois Fortin🇨🇦 · Steven P. Harris🇺🇸 · Kuver Sinha🇺🇸 · Yongchao Zhang🇨🇳

    We derive new constraints on light CP-even scalars using old gamma-ray observations in the direction of SN1987A by the Solar Maximum Mission (SMM) satellite. Light scalars can be abundantly produced in the supernova core via the nucleon bremsstrahlung process, can stream out of the supernova-environment and decay into photons -- either primary photons or secondary photons from lepton-antilepton pairs -- thus leading to a gamma-ray signal. From the non-observation of excess photon flux by SMM after the detection of the neutrino burst from SN1987A, we set new constraints on the mixing angle of the CP-even scalar with the Standard Model Higgs boson.

    hep-phastro-ph.HE3 citations
19. 19*

    Sensitivity of Jet Observables to Molière Scattering Off Quasiparticles in Quark-Gluon Plasma

    Zachary Hulcher🇺🇸 · Arjun Srinivasan Kudinoor🇺🇸 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸

    Quark-gluon plasma (QGP) is a strongly coupled liquid when viewed at length scales of order the inverse of its temperature and longer. However, when it is probed at short enough length scales, asymptotic freedom mandates the presence of quark- and gluon-like quasiparticles. Partons in jets can trigger perturbative, high momentum-exchange $2\to 2$ Molière scatterings off quasiparticles in the medium, making jets useful probes of the microscopic structure of QGP. Prior to this work, soft strongly coupled momentum-exchanges between jet partons and the QGP droplet produced in a heavy-ion collision, as well as the wakes that jets excite in the droplet, had been accounted for in the Hybrid Model of jet quenching. Here, we present a full calculation of Molière scattering off a QGP quasiparticle which results in the deflection of the jet parton and the excitation of a parton from the thermal medium that recoils after being kicked, and describe how it is implemented in the Hybrid Model. The scattered jet and recoil partons continue to propagate through the QGP, lose energy and momentum, excite wakes, and may further re-scatter. Using the Hybrid Model, we study how Molière scatterings impact jet shapes and fragmentation functions, the Soft Drop angle $R_g$, jet girth $g$, and observables that focus on the number and angular distribution of subjets within jets. We demonstrate that photon-tagged jets provide a particularly sensitive probe: selecting events by the photon energy mitigates the selection bias inherent in inclusive jet measurements and enhances sensitivity to rare large-angle scatterings. We find that Molière scatterings broaden both the $R_g$ and $g$ distributions when jets significantly softer than the photon are included. Our results point the way towards distinctive model-independent experimental signatures of hard scattering of jet partons off quasiparticles in QGP.

    hep-phhep-thnucl-exnucl-th4 citations
20. 20*

    Binary-boosted Dark Matter

    Javier F. Acevedo🇨🇦 · Adam Ritz🇨🇦

    We explore the aggregate effect of binary systems on the Milky Way's dark matter (DM) velocity distribution with Monte Carlo simulations. Through gravitational interactions with binaries, transiting DM particles can gain substantial energy. We analyze this mechanism across a range of galactic binaries, and find it to be most effective for double black holes, where ejection speeds can reach $\sim 2000km/s$ while attaining a large ejection rate. We assess the expected binary-boosted DM flux from synthetic populations of black hole binaries in the galaxy, and show direct detection experiments can be sensitive to it. In particular, we demonstrate that large noble liquid detectors such as Lux-Zeplin and PandaX-4T can extend their mass sensitivity down to the sub-GeV scale, and potentially become competitive with other lower-threshold experiments when the full galactic black hole binary population is taken into account. This boosting mechanism, being gravitational in nature, is largely model- and mass-independent.

    hep-phastro-ph.HEJCAP(2026)·4 citations
21. 21*

    Analytic next-to-leading order electroweak corrections to Higgs boson pair production at high energies

    Joshua Davies🇬🇧 · Kay Schönwald🇨🇭 · Matthias Steinhauser🇩🇪 · Hantian Zhang🇨🇭

    We compute the complete next-to-leading order electroweak corrections to the form factors entering gluon-induced Higgs boson pair production. We consider the top quark contribution in the limit where the Mandelstam variables are much larger than all other scales involved in the process and compute about a hundred expansion terms in analytic form. They are used to obtain precise numerical results even for fairly low values of the transverse momentum of the Higgs boson. We show that these electroweak corrections at high energies are of the order of $-10\%$. We also discuss the leading logarithmic corrections of the analytic expressions.

    hep-ph4 citations
22. 22*

    Higher-order hadronic vacuum polarization contribution to the muon $g-2$ from lattice QCD

    Arnau Beltran🇩🇪 · Alessandro Conigli🇩🇪 · Simon Kuberski🇨🇭 · Harvey B. Meyer🇩🇪 · Konstantin Ottnad🇩🇪 · Hartmut Wittig🇩🇪

    We present the first lattice QCD calculation of the next-to-leading order hadronic vacuum polarization contribution to the muon anomalous magnetic moment with sub-percent precision. We employ the time-momentum representation for the space-like kernel, which is combined with the spatially summed vector correlator computed on CLS ensembles with $N_{\mathrm{f}}=2+1$ flavors of $\mathrm{O}(a)$-improved Wilson fermions, covering six lattice spacings between $0.039$ and $0.097$fm and a range of pion masses including the physical value. After accounting for finite-size corrections and isospin-breaking effects, we obtain as our final, continuum-extrapolated result $a_{\mu }^{\mathrm{hvp},\mathrm{nlo}}=-101.57(26{)}_{\mathrm{stat}}(54{)}_{\mathrm{syst}}\times 10^{-11}$. It lies below the estimate provided by the 2025 White Paper of the Muon $(g-2)$ Theory Initiative by $1.4\sigma$ but is two times more precise. It also exhibits a strong tension of $4.6\sigma$ with data-driven evaluations based on hadronic cross section measurements excluding the recent result by CMD-3.

    ↳ hep-lathep-phJHEP(2026)·6 citations
23. 23*

    Studying the QCD phase diagram using pressure derivatives from lattice QCD

    Sipaz Sharma🇩🇪

    We summarize the application of derivatives of the QCD pressure, calculated within the framework of lattice QCD, in constructing observables that probe aspects of the QCD phase diagram at physical quark masses. We outline how the behavior of energy-like and magnetization-like observables at physical quark masses is influenced by the $(2+1)$-flavor chiral phase transition. We describe features of the chiral crossover at vanishing and non-vanishing chemical potentials and discuss deconfinement at zero chemical potential. We address the relevance of the convergence properties of the Taylor expansion of the QCD pressure in the search for the QCD critical endpoint.

    ↳ hep-lathep-exhep-phJ.Subatomic Part.Cosmol.(2026)·0 citations
24. 24*

    General Hamiltonian Approach to the $\mathbf{N}$-Body Finite-Volume Formalism: Extracting the $\omega$ Resonance Parameters from Lattice QCD

    Kang Yu🇨🇳 · Derek B. Leinweber🇦🇺 · Anthony W. Thomas🇦🇺 · Guang-Juan Wang🇯🇵 · Jia-Jun Wu🇨🇳 · Zhi Yang🇨🇳

    We present a nonperturbative Hamiltonian framework (NPHF) to address the general $N$-body problem. This framework rigorously connects finite-volume spectra from lattice QCD to scattering observables from experiment. To demonstrate its applicability, we extract the resonance parameters of the $\omega$ meson by simultaneously analyzing the isoscalar $3\pi$ and isovector $2\pi$ systems. The Hamiltonian unifies single-particle $\omega$, two-particle $\rho \pi$, and three-particle $\pi \pi \pi$ dynamics within a single unitary formalism. Using leading lattice QCD spectra from the Chinese Lattice QCD Collaboration at $m_{\pi }$ = 208 and 305 MeV, we perform a fit in the isovector and isoscalar channels, accurately describe the lattice spectra and obtain robust determinations of the $\rho$ and $\omega$ pole positions. This work establishes a foundational approach for extracting resonance dynamics from finite-volume spectra. Given the ubiquity of three-body dynamics in exotic hadrons, halo nuclei, and neutron star matter, this general formalism holds broad relevance across particle, nuclear, and astrophysical physics.

    ↳ hep-lathep-ph3 citations
25. 25*

    Nuclear Deformation Effects on Charmonium Suppression in Au+Au and U+U Collisions

    Jiamin Liu🇨🇳 · Huanshang Yang🇺🇸 · Baoyi Chen🇨🇳

    We investigate the impact of intrinsic nuclear deformation and orientation on the yield suppression and momentum anisotropy of charmonia in Au+Au and U+U collisions at the Relativistic Heavy-Ion Collider. The anisotropic nucleon density within the nucleus is parameterized using a modified Woods-Saxon distribution, which is incorporated into the initial distributions of both the heavy quarkonia and the bulk medium energy density. The well-established Boltzmann-type transport equation is utilized to describe the dynamical evolution of quarkonium in the anisotropic bulk medium. Treating quarkonium suppression in Au+Au collisions as a baseline, we find that the momentum-integrated charmonium yield suppression is relatively insensitive to the initial nuclear geometry in deformed U+U collisions. In contrast, the anisotropic flow coefficients ($v_n$) of the charmonium is more sensitive to the nuclear deformation. Furthermore, these observables are also connected with the collision configuration, particularly when distinguishing between tip-tip and body-body orientations in U+U collisions at $\sqrt{s_{NN}}=193$ GeV. This effect is more pronounced for the excited state due to its smaller binding energy and heightened sensitivity to the initial energy density of the hot QCD medium.

    ↳ nucl-thhep-phPRC(2026)·1 citation
26. 26*

    Thermal and chemical response from entanglement entropy

    Niko Jokela🇫🇮 · Aatu Rajala🇫🇮 · Tobias Rindlisbacher🇫🇮

    We study entanglement entropy (EE) in interacting quantum field theories (QFTs) at finite density. We argue that, in the limit of large subregions, the derivative of EE with respect to the size of the entangling region approaches the thermal entropy density, independently of microscopic details. We make this relation explicit using slab-shaped subregions, where the limiting behavior can be directly identified. At finite chemical potential, we show that EE satisfies thermodynamic response relations, including a generalized Maxwell relation linking chemical potential and charge density. We provide strong nonperturbative evidence for these statements in the three-dimensional O(4) model, and conjecture that they are generic features of continuum QFTs, establishing a two-way link between entanglement and thermodynamics that opens a route toward extracting the equation-of-state information from entanglement data.

    ↳ hep-thcond-mat.stat-mechhep-lathep-ph+11 citation
27. 27*

    BPS vortex from nonpolynomial scalar QED in a $\text{mathds}C{\mathrm{P}}^1$-Maxwell theory

    F. C. E. Lima🇧🇷

    We investigate a generalized gauged $\text{mathds}C{\mathrm{P}}^1$-Maxwell theory in which the electromagnetic sector acquires a field-dependent magnetic permeability generated dynamically through fermionic vacuum polarization. Starting from the gauged $\text{mathds}C{\mathrm{P}}^1$-sigma model, whose dynamics occurs on a curved target space endowed with the Fubini-Study metric, we show that integrating out a Dirac fermion with effective mass induces, at one loop, a non-polynomial magnetic permeability, which after dimensional reduction to $(2+1)$-dimensions yields an effective Maxwell sector takes the form of a logarithmic magnetic permeability. Within this framework, one builds a generalized $\text{mathds}C{\mathrm{P}}^1$-Maxwell model by admitting Bogomol'nyi-Prasad-Sommerfield (BPS) configurations. Taking this into account, we solved the self-dual equations that describe vortex-like solutions with quantized magnetic flux. Furthermore, one highlights the interactions between the target-space geometry and the induced permeability.

    ↳ hep-thhep-ph1 citation
28. 28*

    Gravitational waves in metric-affine bumblebee gravity

    A. A. Araújo Filho🇧🇷

    We study the propagation and emission of gravitational waves in the metric-affine formulation of the bumblebee model, where spontaneous Lorentz symmetry breaking arises from a vector field acquiring a nonvanishing vacuum expectation value. Working in the geometric-optics limit of the linearized theory, we derive the modified dispersion relation governing the graviton modes and show that it depends on the orientation of the wave vector relative to the background vector. The polarization sector is examined for timelike and spacelike configurations of the Lorentz-violating vacuum. In both cases only two independent tensor modes propagate, although their propagation properties and tensor structure depend on the orientation of the background field. We then construct the retarded Green function associated with the modified wave operator and determine the radiation-zone produced by localized sources. In the timelike configuration the Lorentz-violating effects appear through a modified propagation speed and an overall amplitude renormalization, leading to a shifted retarded time while preserving the quadrupole structure of the waveform. In contrast, the spacelike sector introduces anisotropic corrections to the quadrupole amplitude together with an additional contribution proportional to the third time derivative of the quadrupole moment. As an astrophysical application, the gravitational radiation emitted by a circular binary black hole system is evaluated, allowing observational constraints on the Lorentz-violating combination $\xi b^2$ to be estimated using multimessenger bounds from GW170817/GRB~170817A and waveform consistency requirements from gravitational wave observations.

    ↳ gr-qchep-phhep-thEPJC(2026)·3 citations
29. 29*

    Effects of fermions in one-loop propagators in the Curci-Ferrari-Delbourgo-Jarvis gauge

    Santiago Cabrera🇺🇾 · Marcela Peláez🇺🇾 · Matthieu Tissier🇫🇷

    We present the one-loop computation of the quark propagator in the Curci-Ferrari-Delbourgo- Jarvis (CFDJ) gauge, extending previous analyses to include dynamical quarks. Using the infrared- safe renormalization scheme, we study how finite gauge parameters affect the infrared behavior of QCD correlation functions. The coupling, gluon mass, and gauge parameter are found to freeze below a finite energy scale, confirming the infrared stability of the framework. The quark dressing function Z(p) shows a change in concavity between the Landau and finite-{\xi} cases, suggesting that nonvanishing gauges may better reproduce lattice trends. These results establish the CFDJ gauge as a possible infrared-safe setting candidate for perturbative QCD with massive gluons. In the case of a consistency check from lattice calculations, it could provide a basis for future studies of the quark-gluon vertex and related observables.

    ↳ hep-thhep-lathep-phPRD(2026)·1 citation
30. 30*

    Circular stable orbits in $f(R)$ realistic static and spherically-symmetric spacetimes

    Néstor Rivero González🇪🇸 · Álvaro de la Cruz Dombriz🇪🇸 · Gonzalo J. Olmo🇪🇸

    We investigate the geodesic structure of realistic static and spherically symmetric spacetimes embedding neutron stars in metric $f(R)$ gravity, focusing on the quadratic Starobinsky model $f(R)=a{R}^2$ with $a<0$. Neutron-star solutions are obtained by numerically solving the modified Tolman-Oppenheimer-Volkoff system for several realistic equations of state. Such solutions are then matched consistently to the exterior vacuum geometry by enforcing the full set of junction conditions required in metric $f(R)$ theories. Using an effective potential approach, we show that stable circular orbits appear in discrete radial bands separated by forbidden regions, with a dominant principal band of stability that depends sensitively on the stellar central pressure, the equation of state, and the magnitude of the parameter $|a|$. Outside the stable bands, massive particles can have bound but unstable precessing trajectories as well as unbounded motions. On the other hand, for null geodesics, we find no evidence for photon spheres outside the neutron star within the parameter range studied.

    ↳ gr-qchep-phPRD(2026)·0 citations
31. 31*

    Black Hole Mergers as the Fastest Photon Ring Scramblers

    D. Giataganas🇹🇼 · G.F. Giudice🇦🇪 · A. Ianniccari🇨🇭 · A.J. Iovino🇦🇪 · A. Kehagias🇬🇷 · F. Quevedo🇦🇪 · D. Perrone🇨🇭 · A. Riotto🇨🇭

    Black holes are the most efficient scramblers in nature. By mapping the instantaneous mass and angular momentum of two spinless black holes in a quasi-circular binary onto those of an effective Kerr black hole, we demonstrate that the final state of the merger remnant corresponds with remarkable accuracy to the configuration that renders null geodesics unstable at the highest possible rate. This suggests a deep connection between the properties of black holes resulting from binary mergers and their unstable null orbits.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2026)·1 citation
32. 32*

    Multimessenger Characterization of High-Energy Neutrino Emission from the Brightest Neutrino-Active Galactic Nuclei

    Jose Alonso Carpio🇺🇸 · Ali Kheirandish🇺🇸 · Kohta Murase🇺🇸

    The observation of high-energy neutrinos from the direction of the nearby active galaxy, NGC 1068, was a major step in identifying the origin of high-energy cosmic neutrinos. The multimessenger data imply that high-energy neutrinos originate from the hearts of active galaxies which are opaque to GeV-TeV $\gamma$-rays. This realization is reinforced by the excess of neutrinos in the direction of NGC 4151 and Circinus Galaxy, other nearby active galactic nuclei (AGNs). Understanding the vicinity of supermassive black holes with electromagnetic radiation is often challenging due to uncertainties associated with the absorption of emission in these dense environments, and neutrinos can be used as a powerful probe of the inner parts of the active galaxies. Considering the five brightest neutrino-active galaxies, NGC 1068, NGC 4151, CGCG 420-15, Circinus Galaxy, and NGC 7469, we employ the measured neutrino spectra together with the sub-GeV $\gamma$-ray emission measured by the {\em Fermi} satellite to break the degeneracy and narrow in on the parameter space of neutrino emission from turbulent coronae of AGNs. We also study contributions of jet-quiet AGNs, whose properties are similar to NGC 1068 and NGC 7469, to the isotropic neutrino background flux, through exploring possibilities that the neutrino luminosity function may deviate from the X-ray luminosity function. Our results will help estimate the prospects for identifying additional neutrino-active galaxies and guide future targeted analyses.

    ↳ astro-ph.HEhep-phApJ(2026)·6 citations
33. 33*

    Binary Black Holes population synthesis based on the current LVK observations

    Mehdi El Bouhaddouti🇺🇸 · Ilias Cholis🇺🇸 · Muhsin Aljaf🇺🇸

    The ongoing observations from ground based gravitational-wave observatories have led to the detection of more than a hundred merger events between black holes. We use the LIGO-Virgo-KAGRA (LVK) observations from 2015 to early 2024, to test the population synthesis of these merging binaries; which will allow us to probe the formation mechanisms and environments of these black holes. We test if the current sample of binary black holes can be explained only by the merger of black holes coming from the collapse of the cores of massive stars, i.e. as just first generation black holes merging with each other. Those black holes' masses will roughly follow a power-law distribution. We also test if in addition to the merger between first generation black holes, there is evidence for a second population of black hole binaries in which at least one the binaries' members is the product of an earlier merger between black holes. These binaries are typically referred to as signals of hierarchical mergers. Such a population can possibly explain the observation of very massive black hole binaries by the LVK collaboration. We find that the LVK observations give a statistical preference in log-likelihood of up to $-2\Delta ln\mathcal{L}=-150$ or in log-Bayes factor of up to $ln\text{BF}=71$, for the full sample of black hole binaries originating from a combination of black holes following a power-law distribution and black holes from hierarchical mergers. The ratio of black holes following a power-law mass-distribution to a mass-distribution expected from hierarchical mergers is found to be as high as one-to-one. We also consider that some of the LVK black hole merging binaries are the result of primordial black holes (PBHs), merging inside dark matter halos and in the intergalactic medium. Adding a third population is preferred. [abridged]

    ↳ astro-ph.COastro-ph.GAastro-ph.HEgr-qc+15 citations
34. 34*

    All-Loop Renormalization and the Phase of the de Sitter Wavefunction

    Alexander Farren🇬🇧 · Ciaran McCulloch🇬🇧 · Enrico Pajer🇬🇧 · Xi Tong🇬🇧

    Cosmological observables of the primordial universe are encoded in the late-time field-theoretic wavefunction. For shift-symmetric scalars in de Sitter, a good approximation for many inflationary models, the wavefunction must be purely real at tree-level. This property is violated by a quantum anomaly in the process of renormalization. As a result, we show that the imaginary part of the wavefunction is fixed by its dependence on the renormalization scale to all loop orders in perturbation theory. This follows from unitarity, locality, dilation isometry and a Bunch-Davies state. The compact relation we uncover for the wavefunction implies an infinite set of relations among correlators of massless fields and their conjugate momenta, which we exemplify at one-loop order.

    ↳ hep-thastro-ph.COgr-qchep-ph7 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.