Fri·Apr 17, 2026Friday·April 17, 2026

1. 01*

   Logarithmic EW corrections at two-loop

   J. M. Lindert🇬🇧 · L. Mai🇮🇹

   We present the implementation of next-to-next-to-leading order (NNLO) electroweak (EW) virtual corrections at next-to-leading logarithmic (NLL) accuracy in the amplitude generator OpenLoops. The implementation covers the automated computation of processes involving massless fermions and transversely polarised vector bosons. For energies above the EW scale, logarithmic EW corrections are strongly enhanced in the tails of kinematic distributions of key LHC processes, reaching several tens of percent at NLO and several percent at NNLO. The two-loop implementation is validated against analytical results from the literature. We present phenomenological results for representative LHC processes and discuss the role of two-loop EW corrections in reducing theoretical uncertainties from missing higher-order contributions.

   hep-phEPJC(2026)·2 citations
2. 02*

   Astrophysical bounds on the high-energy evolution of neutrino mixing

   Mauricio Bustamante🇩🇰 · Qinrui Liu🇨🇦 · Gabriela Barenboim🇪🇸

   While conventional oscillation experiments measure neutrino mixing parameters with high precision, these measurements are strictly confined to sub-TeV scales. At higher energies, renormalization-group effects can cause these parameters to evolve with the transferred momentum, $Q$. High-energy and ultra-high-energy astrophysical neutrinos, spanning TeV to EeV energies, probe high values of $Q$ unreachable by conventional experiments, offering an unprecedented test of high-energy mixing. We use the flavor composition of these neutrinos -- the relative proportions of ${\nu }_e$, ${\nu }_{\mu }$, and ${\nu }_{\tau }$ -- to constrain this evolution, both phenomenologically and within dimension-6 Standard Model Effective Field Theory. We account for astrophysical uncertainties -- an unavoidable requirement to obtain realistic results, even though this weakens the bounds. Although present IceCube measurements lack the sensitivity to detect this running, we forecast that upcoming multi-detector combinations will place unprecedented bounds on the high-energy evolution of neutrino mixing.

   hep-phastro-ph.HEhep-exhep-th2 citations
3. 03*

   Wave-envelope dark matter beyond the monochromatic paradigm

   Yechan Kim🇰🇷 · Hye-Sung Lee🇰🇷

   Ultralight dark matter searches widely assume that signals are monochromatic, with a single frequency set by the mass. This assumption is generally violated in the presence of field mixing, even when the constituent fields have similar frequencies. Instead, dark matter signals can exhibit a two-timescale structure with intrinsic slow modulation. We demonstrate that mixing between ultralight wave dark matter fields induces a parametric structure, leading to a scenario we refer to as wave-envelope dark matter, in which a slow-beating envelope emerges alongside the primary oscillation. This results in distinctive features such as slow modulation and characteristic sideband structures in the frequency spectrum, beyond the conventional monochromatic expectation. As a representative example, we briefly discuss implications for neutrino observables.

   hep-ph0 citations
4. 04*

   The ${\Lambda }_c{\Sigma }_c$ dibaryon and ${\bar{\Lambda }}_c{\Sigma }_c\pm {\bar{\Sigma }}_c{\Lambda }_c$ baryonium states via the QCD sum rules

   Xiu-Wu Wang🇨🇳 · Zhi-Gang Wang🇨🇳 · Guo-Liang Yu🇨🇳

   In the present work, we study the ${\Lambda }_c{\Sigma }_c$ dibaryon and ${\bar{\Lambda }}_c{\Sigma }_c\pm {\bar{\Sigma }}_c{\Lambda }_c$ baryonium states via the QCD sum rules. We construct four (eight) currents with definite $J^P$ ($J^{PC}$) to interpolate the dibaryon (baryonium) states and obtain twelve QCD sum rules. For the dibaryon states, the state with the $J^P=1^{+}$ lies below the ${\Lambda }_c{\Sigma }_c$ threshold, and is a molecule candidate. For the baryonium states, the states with the $J^P=0^{-\pm }$ and $1^{-\pm }$ lie below the ${\bar{\Lambda }}_c{\Sigma }_c$ threshold, and are four molecule candidates. The present predictions can be confronted to the experimental data in the future and make contributions to the exotic spectroscopy.

   hep-ph1 citation
5. 05*

   Inflaton Regeneration via Scalar Couplings: Generic Models and the Higgs Portal

   Kunio Kaneta🇯🇵 · Tomo Takahashi🇯🇵 · Natsumi Watanabe🇯🇵

   The standard cosmological paradigm assumes that the inflaton field becomes dynamically negligible during the post-reheating evolution of the Universe. We demonstrate that this assumption fails for a broad class of inflationary models where the potential behaves as a monomial form $V(\varphi )\propto {\varphi }^k$ (with $k\ge 4$) around the minimum. In such scenarios, the effective inflaton mass depends on the field amplitude and vanishes asymptotically as the Universe expands. This vanishing-mass mechanism renders the inflaton kinematically accessible to the thermal plasma long after reheating, facilitating the regeneration of inflaton quanta through 1-to-2 decays and 2-to-2 scatterings of bath particles. This mechanism is quite generic and the coupling responsible for reheating can be constrained if the inflaton is overproduced, while the inflaton quanta can constitute dark matter in specific scenarios. Furthermore, if reheating occurs via the Standard Model Higgs portal, the process can be further constrained by big bang nucleosynthesis, cosmic microwave background, and colliders such as the LHC. This mechanism provides a new framework for probing post-inflationary reheating.

   hep-phastro-ph.CO0 citations
6. 06*

   Mechanical properties of proton in the momentum space

   Navpreet Kaur🇮🇳 · Shubham Sharma🇷🇺 · Abi Jebarson A🇮🇳 · Harleen Dahiya🇮🇳

   We study the parametrization of the energy-momentum tensor for the case of a proton in momentum space in terms of gravitational transverse momentum-dependent distributions (TMDs). These gravitational TMDs are investigated with the inclusion of higher-twist contributions to predict the mechanical properties, specifically the transverse pressure and shear force distributions, along with the polarization-dependent ${\Pi }_S^q$ and ${\Pi }_A^q$ terms. The corresponding distributions are computed individually for both $u$ and $d$ quark flavors. The calculations have been performed in the light-cone framework using the spectator diquark model. A strong binding contribution to the transverse pressure is observed in the low-momentum space for both quark flavors of the proton.

   hep-phPLB(2026)·1 citation
7. 07*

   Exploring non-equilibrium effects in sequential freeze-in

   Shiuli Chatterjee🇵🇱 · Andrzej Hryczuk🇵🇱

   Freeze-in of multi-component dark sectors is governed not only by the interaction with the thermal plasma, but also by their internal dynamics. Full thermalisation within the dark sector is not guaranteed, raising the question of impact of departures from local thermal equilibrium onto the evolution and ultimately relic abundance and momentum distribution of dark matter. In this work we explore this question in a minimal two-scalar model, which can give rise to observable signatures in indirect detection and long-lived particle searches at forward physics experiments. Focusing on the phenomenologically viable regions, we analyse the impact of non-thermal evolution on the dark matter abundance, finding deviations of up to an order of magnitude between the full phase-space treatment and the traditional number-density approach. Our results highlight the importance of phase-space level computation for accurate freeze-in predictions and further motivate dedicated numerical tools for studying the evolution of multi-component dark sectors at the phase space level.

   hep-phastro-ph.CO1 citation
8. 08*

   Rescattering effects in near-threshold $J/\psi$ photoproduction

   S. Sakinah🇰🇷 · Sang-Ho Kim🇰🇷 · H. M. Choi🇰🇷

   We investigate near-threshold $J/\psi$ photoproduction off the nucleon, focusing on hadronic rescattering effects induced by open-charm meson-baryon intermediate states. Beyond the conventional Pomeron-exchange mechanism, the ${\bar{D}}^0{\Lambda }_c^{+}$ and ${\bar{D}}^{\ast 0}{\Lambda }_c^{+}$ channels are incorporated within an effective Lagrangian framework. The relevant production amplitudes are evaluated at tree level from $t$-, $s$-, and $u$-channel diagrams in a gauge-invariant manner. The resulting total and $t$-dependent differential cross sections are compared with recent near-threshold data from the GlueX, $J/\psi$-007, and CLAS experiments at Jefferson Lab. We find that the open-charm rescattering contributions significantly improve the description of the data, particularly at large momentum transfer, and naturally generate cusp-like structures near the ${\bar{D}}^0{\Lambda }_c^{+}$ and ${\bar{D}}^{\ast 0}{\Lambda }_c^{+}$ thresholds in the GlueX data. We further present predictions for the associated open-charm processes $\gamma p\to {\bar{D}}^{(\ast )0}{\Lambda }_c^{+}$, whose cross sections are estimated to be of the order of 5 nb.

   hep-ph1 citation
9. 09*

   Status of the hadronic light-by-light contribution to the muon $g-2$ and holographic QCD predictions

   Anton Rebhan🇦🇹 · Luigi Cappiello🇮🇹 · Josef Leutgeb🇦🇹 · Jonas Mager🇦🇹

   We review the recent progress made with regard to the hadronic light-by-light (HLbL) contribution to the Standard Model prediction of the muon anomalous magnetic moment and how well this compares with predictions from holographic QCD models, which had predicted larger contributions from axial vector mesons and short-distance constraints than the White Paper of 2020. A new holographic prediction concerns tensor-meson contributions, which in holographic QCD play a significant role in short-distance constraints beyond the Melnikov-Vainshtein constraint. When matching also the symmetric longitudinal short-distance constraint, the resulting prediction for the tensor-meson transition form factors agree well with available singly virtual data, but lead to different results than the traditional quark-model ansatz and a sizable positive contribution that could explain the remaining current tension between lattice and data-driven results for the HLbL contribution.

   hep-ph1 citation
10. 10*

    Phenomenology of Vanishing Effective Majorana Mass with a Sterile Neutrino under Cosmological and JUNO Constraints

    Rushi Chambyal🇮🇳 · Tapender · Labh Singh🇮🇳 · Surender Verma🇮🇳

    In the present work we investigate the phenomenological implications of a vanishing effective Majorana neutrino mass within a $3+1$ neutrino framework adding a eV-scale sterile neutrino beside three active neutrino states in light of latest cosmology driven bounds on sum of neutrino masses (${\sum }_i{m}_i$). We explore the parameter space where the destructive interference between active and sterile states leads to vanishing amplitude, $M_{ee}$, of neutrinoless double beta ($0\nu \beta \beta$) decay. The allowed parameter space has been identified and predictions have been obtained taking into account the latest Planck and DESI+CMB bound on ${\sum }_i{m}_i$. We find that these bounds restrict the sterile mixing angle ${\theta }_{14}$ and the lightest active neutrino mass. Furthermore, we incorporate the refined precision data from JUNO experiment regarding solar oscillation parameters (${\theta }_{12},\Delta m_{21}^2$). We find that the sterile neutrino parameters like ${\theta }_{14}$ may not be sensitive to the JUNO precision measurements as the constraint imposed by precise ${\theta }_{12}$ is washed out by new cancellations driven through additional CP violating phases leading to vanishing $|M_{ee}|$.

    hep-phhep-th1 citation
11. 11*

    Glauber-Lachs formula-based analysis of three-pion Bose-Einstein correlation data in $pp$ collisions at 7 TeV from the LHCb Collaboration

    Takuya Mizoguchi🇯🇵 · Seiji Matsumoto🇯🇵 · Minoru Biyajima🇯🇵

    In this study, we combine the Glauber--Lachs formula from quantum optics and the two-component picture for pion production to analyze data on two- and three-pion Bose--Einstein correlation in $pp$ collisions at 7 TeV from the LHCb Collaboration. For the pion exchange function $E_{2B}$, we chose a dipole form and an inverse one-and-a-half pole form. The extensions are computed in the configuration space of four-dimensional Euclidean space ($\xi =\sqrt{|r_1-r_2{|}^2+(t_1-t_2{)}^2}$).

    hep-phhep-ex0 citations
12. 12*

    Production of doubly heavy quarkonium associated with two heavy quarks via top quark decays

    Juan-Juan Niu🇨🇳 · Xu-Chang Zheng🇨🇳 · Hong-Hao Ma🇨🇳

    In this paper, we analyze the $1\to 4$ decay channel for the production of doubly heavy quarkonium, $(b\bar{c})$ or $(c\bar{c})$, via top-quark decays, $t\to (b\bar{c})+c+c+\bar{s}$ and $t\to (c\bar{c})+b+c+\bar{s}$, within the framework of nonrelativistic QCD (NRQCD). The dominant contributions are considered in color-singlet S-wave states, i.e., $(b\bar{c}){[}^1{S}_0]$, $(b\bar{c}){[}^3{S}_1]$, $(c\bar{c}){[}^1{S}_0]$, and $(c\bar{c}){[}^3{S}_1]$. Our calculations show that the decay widths for $\overline{B_c}$, $\overline{B_c^{\ast }}$, ${\eta }_c$ and $J/\psi$ production are 0.2251, 0.3099, 0.0537 and 0.0555 MeV, respectively, resulting in $\mathcal{O}(10^4\text{–}10^6)$ level of ${\bar{B}}_c^{(\ast )}$ events and $\mathcal{O}(10^3\text{–}10^5)$ level of charmonium produced at LHC per year. In particular, we find that the dominant contribution to ${\eta }_c$ and $J/\psi$ production via top-quark decays arises from this decay channel proposed in this work. Moreover, this multi-body top-quark decay process can serve as a sensitive probe for validating the narrow-width approximation (NWA). Finally, we provide a detailed analysis of theoretical uncertainties and differential distributions to facilitate the corresponding experimental searches. The production of a hadron associated with three quarks contains rich physical information, providing new insights for the LHC to study $B_c$ mesons and charmonia.

    hep-ph0 citations
13. 13*

    Symmetry Preserving Contact Interaction Approaches: An Overview of Meson and Diquark Form Factors

    L.X. Gutiérrez-Guerrero🇲🇽 · Roger José Hernández-Pinto🇲🇽

    We present an updated overview of the symmetry preserving Contact Interaction model in hadronic physics, developed a little over a decade ago to describe the mass spectrum and internal structure of mesons and diquarks composed of light and heavy quarks. Over the years, the Contact Interaction has evolved into a framework capable of treating both ground and excited states, providing a simple yet consistent approach to nonperturbative QCD. In this review, we examine the mass spectrum and elastic form factors of forty mesons with different spins and parities, together with their corresponding diquark partners. Importantly, we update the comparison of Contact Interaction predictions using recent results from the literature, offering a fresh perspective on the model's performance, strengths, and limitations. The analysis presented here refines previous conclusions and supports the Contact Interaction as a practical tool for hadron structure studies, with potential applications to baryons and multiquark states. We also present comparisons with other theoretical models and approaches, including lattice quantum chromodynamics, and comment on future prospects in view of ongoing and planned hadron structure experimental programs. In particular, forthcoming measurements at FAIR, together with future studies at Jefferson Lab and the Electron Ion Collider, are expected to provide key insights into hadron structure, with FAIR offering indirect constraints via hadron spectroscopy, hadronic interactions, and in-medium properties, while high-precision data on meson structure and form factors from Jefferson Lab and the Electron Ion Collider will provide valuable benchmarks to confront Contact Interaction based predictions.

    hep-phhep-thParticles(2026)·6 citations
14. 14*

    Dilaton-Flattened Axion Inflation

    Pirzada🇨🇳 · Ali Muhammad🇨🇳 · Tianjun Li🇨🇳 · Imtiaz Khan🇨🇳 · Mussawir Khan🇨🇳

    We present a solvable same-sector effective theory for anomaly-inspired axion inflation, in which a heavy trace-anomaly mode dynamically backreacts on the axion potential. The tree-level elimination of the radial field resums the backreaction into a closed-form Lambert-$W$ potential, naturally flattening the hilltop potential without external plateau operators. By deriving the exact trough metric, we evaluate all the observables on the fully reduced one-field action, bypassing uncontrolled kinetic approximations. Calibrated at $N_{\star }=56$, reheating-compatible branches yield $r\simeq 0.033$--$0.036$ and ${\alpha }_s\simeq -(4.6$--$4.7)\times 10^{-4}$, comfortably satisfying the current ACT/SPT/BICEP constraints. The evolution remains strictly adiabatic ($m_{\perp }^2/H^2\gtrsim 6.1$, $\Omega /H\lesssim 7.6\times 10^{-4}$) with negligible sound-speed and metric corrections. We provide analytic control over the constant-$w_{\mathrm{eff}}$ reheating map, the $N_{\mathrm{re}}=0$ boundary, and robustness against vacuum-offset deformations. This Lambert-$W$ backbone establishes a precise, deformable benchmark for confining axion inflation, with microscopic matching and reheating microphysics accessible as systematic EFT refinements.

    hep-phgr-qcJCAP(2026)·6 citations
15. 15*

    Echoes of Global Cosmic Strings

    Jeff A. Dror🇺🇸 · Antonios Kyriazis🇺🇸

    If the Universe underwent a cosmic phase transition, it may have left behind a network of cosmic strings. When these strings arise from the breaking of a gauge symmetry, their decay produces a significant stochastic background of gravitational waves. In contrast, if they originate from the breaking of a global symmetry, their decay predominantly yields Nambu-Goldstone bosons, which can persist as dark matter or dark radiation. In this work, we assess the detectability of this particle spectrum using a range of cosmological probes. We employ semi-numerical methods to estimate the resulting energy density and compute the associated matter power spectrum. We then compare these predictions with observations of the cosmic microwave background, Lyman-$\alpha$ forest, large-scale structure surveys, and the UV luminosity function, thereby deriving constraints on the Nambu-Goldstone boson mass and the symmetry-breaking scale. Finally, we present projections for the sensitivity of upcoming cosmic microwave background missions.

    hep-phastro-ph.COPRD(2026)·1 citation
16. 16*

    The $Z_3$ soft breaking in the I(2+1)HDM and its cosmological probes

    M. A. Arroyo-Ureña🇲🇽 · J. Hernández-Sánchez🇲🇽 · C. G. Honorato🇲🇽 · S. Moretti🇬🇧 · T. Shindou🇯🇵

    A $Z_3$ symmetric 3-Higgs Doublet Model (3HDM) with two inert doublets and one active doublet (which plays the role of the Higgs doublet), the so-called I(2+1)HDM, is studied. We discuss the behaviour of this 3HDM realisation when one allows for a $Z_3$ soft-breaking term. In this setup, the lightest $Z_3$ charged neutral scalar can be a Dark Matter (DM) candidate. If the breaking scale is small enough, this model provides a long-lived neutral state with the opposite CP parity to the DM state. This long-lived particle could then be another effective DM candidate when its lifetime is comparable to the age of the universe. In this case, we have studied the properties of the ensuing relic density in the presence of the most recent limits from direct searches for DM. Conversely, the case in which the long-lived particle actually decays into the DM particle and Standard Model particles in a detector at a collider experiment is very attractive from the viewpoint of phenomenology. Under such conditions, we have studied signatures involving missing transverse energy and multiple leptons (and jets) at the International Linear Collider (ILC) in the presence of displaced vertices.

    hep-phhep-ex0 citations
17. 17*

    Entropy considerations in Many-Body Gravity and General Relativity, and the impact on cosmic inflation

    S Ganesh🇮🇳

    Many body gravity (MBG) is a novel modified theory of gravity formulated in a 5-D space-time-temperature framework, in which the variation in temperature is recast as a variation in the 5-D metric. Previous work on MBG has shown that it can reproduce galaxy rotation curves, radial acceleration relation and the weak gravitational lensing of the bullet cluster, without the inclusion of dark matter. In this work we show that MBG can reproduce cosmic inflation, and in the process, analyze fundamental relations between interaction, time and gravity. To analyze cosmic inflation using interacting massless scalar fields, we first analyze theoretically a hypothetical universe with a single massive particle, or a collection of non-interacting massive particles. A quantitative relation between time and interaction is developed using Quantum Field Theory (QFT), which suggests that the notion of time becomes ill-defined for such a universe. The mass terms in MBG and General Relativity cause a discrepancy with the QFT results. An interacting massless scalar field then becomes a necessity to resolve the issue at the onset of inflation. However, the entropic terms in the MBG field equations are seen to be consistent with the QFT results and further accelerate inflation. The slow-roll condition is shown to be a natural consequence of the Euler-Lagrange equations of motion governing the massless scalar field in 5-D space-time-temperature, during the early phase of inflation. Finally, the MBG field equations are solved in the context of a Friedmann metric, leading to inflation. The matter era is also investigated.

    ↳ gr-qchep-phhep-thmath-ph+10 citations
18. 18*

    Loop integrals in de Sitter spacetime: The parity-split IBP system and $\mathrm{d}\log$-form differential equations

    Jiaqi Chen🇨🇳 · Bo Feng🇨🇳 · Zhehan Qin🇨🇳 · Yi-Xiao Tao🇨🇳

    We develop integration-by-parts (IBP) reduction and differential equations for massive loop integrals of cosmological correlators in de Sitter (dS) spacetime, demonstrating the feasibility of this approach. We identify a structural property of the dS IBP system: for an $n$-propagator family, it splits into $2^n$ closed subsystems classified by the parity of the propagator indices. We further formulate a Baikov representation for loop integrals in dS space and derive the corresponding dimensional recurrence relations. In flat spacetime, intersection theory shows that $\mathrm{d}\log$-form master integrands lead to $\mathrm{d}\log$-form differential equations. Motivated by fibration intersection theory, we conjecture that this construction extends to dS integrands involving Hankel functions. We verify this conjecture in the one-loop bubble family and determine the associated alphabet.

    ↳ hep-thgr-qchep-ph5 citations
19. 19*

    An efficient Wavelet-Based Hamiltonian Formulation of Quantum Field Theories using Flow-Equations

    Mrinmoy Basak🇮🇳 · Debsubhra Chakraborty🇮🇳 · Nilmani Mathur🇮🇳

    We propose an effective Hamiltonian formulation of quantum field theories using a Daubechies wavelet basis in position space. Combined with flow-equation methods of the similarity renormalization group (SRG), this approach provides an efficient framework for analyzing quantum field theories by reducing the dimensionality of the Hamiltonian and systematically decoupling degrees of freedom across scales. As an application, the free scalar field theory has been reformulated within this framework to calculate the low-lying energy spectrum of the theory. These basis elements are known to transform the free scalar field theory into a theory of coupled localized oscillators, each of which is labeled by a location and a resolution index. In this representation, the Hamiltonian is naturally organized into fixed-resolution blocks, alongside blocks associated with the interactions between different resolutions. To decouple the different resolution modes and obtain a block diagonalized Hamiltonian with each block associated with a fixed resolution, the flow equation approach of SRG is applied. Finally, we demonstrate that with increasing resolution, the low-energy spectrum can be extracted from the effective lowest-resolution block of the Hamiltonian, leading to a significant reduction in computational cost.

    ↳ hep-lathep-phhep-thPRD(2026)·0 citations
20. 20*

    Charmed baryon decays at BESIII

    Xudong Yu (on behalf of the BESIII Collaboration)🇨🇳

    BESIII has accumulated 4.5 fb${}^{-1}$ of $e^{+}{e}^{-}$ collision data in the 4.6 to 4.7 GeV energy range, corresponding to the world's largest sample of ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ pairs. This paper summarizes recent BESIII results on charmed-baryon decays, including the observation of the rare semi-leptonic decay ${\Lambda }_c^{+}\to n{e}^{+}{\nu }_e$ using a Graph Neural Network, the first measurement of the decay asymmetry in the pure $W$-exchange decay ${\Lambda }_c^{+}\to {\Xi }^0{K}^{+}$, and branching fraction measurements of the inclusive decays ${\Lambda }_c^{+}\to X{e}^{+}{\nu }_e$ and ${\bar{\Lambda }}_c^{-}\to \bar{n}X$. We also report partial wave analyses of ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}{\pi }^0$ and ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}\eta$, measurements of Cabibbo-suppressed decays such as ${\Lambda }_c^{+}\to p{\pi }^0$, and studies of $K_S^0-K_L^0$ asymmetries in ${\Lambda }_c^{+}$ decays.

    ↳ hep-exhep-phJ.Subatomic Part.Cosmol.(2026)·0 citations
21. 21*

    Deeper analysis of Fermi-LAT unassociated 4FGL J2112.5-3043 for possible identification

    Federica Giacchino🇪🇸 · Cristina Fernández-Suárez🇪🇸 · Miguel Á Sánchez-Conde🇪🇸 · M.Ángeles Pérez-García🇪🇸 · Stefano Ciprini🇮🇹 · Dario Gasparrini🇮🇹

    In the 4FGL-DR4 point-source catalog of the Large Area Telescope (LAT) onboard NASA's Fermi Gamma-ray Observatory (Fermi-LAT), around a third of the sources are still unidentified (unIDs). In this work, we perform a detailed study of one of them, namely 4FGL J2112.5-3043. Only gamma-ray emission has been detected from this unidentified source, with no counterpart observed at any other wavelength as of today. Together with its high detection significance, this makes 4FGL J2112.5-3043 a particularly compelling target for further investigation. The results of our spectral and spatial analyses show that the source photon spectrum is better described with a subexponential cutoff power-law spectral model, with no significant flux variability over time, and a morphology consistent with being a point-like source. We investigate and discuss the characterized emission within the context of both conventional and exotic astrophysics, namely a pulsar origin or potential dark matter (DM) annihilations in a nearby Galactic subhalo. Although our results are inconclusive and neither confirm a DM origin nor firmly establish an astrophysical nature, we find a spectral preference for the $b\bar{b}$ and $c\bar{c}$ DM annihilation channels over a pulsar origin, thus making this unID a particularly intriguing candidate for next multiwavelength observations.

    ↳ astro-ph.HEhep-exhep-phPhys.Dark Univ.(2026)·0 citations
22. 22*

    Microscopic primordial black holes as macroscopic dark matter from large extra dimensions

    Giuseppe Filiberto Vitale🇮🇹 · Gaetano Lambiase🇮🇹 · Tanmay Kumar Poddar🇬🇧 · Luca Visinelli🇮🇹

    We study the coupled cosmological evolution of primordial black holes (PBHs) and radiation in the Arkani-Hamed-Dimopoulos-Dvali (ADD) framework with $n$ large extra dimensions and a fundamental gravity scale $M_{\star }$ at the TeV scale. For PBHs with horizon radius smaller than the compactification scale, the higher-dimensional geometry implies a larger horizon size at fixed mass and therefore a suppressed Hawking temperature. As a result, radiation accretion can overcome evaporation in the early Universe and drive a ``runaway'' phase of rapid mass growth. By numerically solving the coupled mass and energy-density evolution equations, we show that for $n\ge 2$ initially microscopic PBHs with initial mass $M_i\gtrsim 10^{12}$g can grow by many orders of magnitude and potentially reach macroscopic, even solar-mass, scales by matter-radiation equality. We determine the critical initial abundance ${\beta }_{\mathrm{crit}}$ required for PBHs to account for the observed dark matter density and find that extra dimensions dramatically lower this threshold, allowing viable scenarios with ${\beta }_{\mathrm{crit}}\sim 10^{-44}$. This identifies a previously unexplored region of parameter space in which the dark matter abundance is achieved through dynamical mass growth rather than large initial collapse fractions.

    ↳ astro-ph.COhep-phJCAP(2026)·2 citations
23. 23*

    Cosmology of Inelastic Self-Interacting Dark Matter: Linear Evolution and Observational Constraints

    Xin-Chen Duan🇨🇳 · Yue-Lin Sming Tsai🇨🇳 · Ziwei Wang🇨🇳

    We study the linear cosmological evolution of inelastic self-interacting dark matter in a two-component dark sector with a small mass splitting, assuming thermal initial conditions for the two species. We derive the coupled background and perturbation equations for inelastic conversion between the two species, considering both power-law and low-velocity saturation cross sections. Exothermic conversion injects kinetic energy into the light component, generating pressure support that suppresses small-scale structure and produces dark acoustic oscillations in the matter power spectrum. The resulting cutoff at scale $k>1h{\mathrm{Mpc}}^{-1}$ depends on the normalization and velocity dependence of the cross section, the dark matter mass and the mass splitting. Using linear power spectra computed with a modified Boltzmann solver, we apply recast constraints from Lyman-$\alpha$ forest data and high-redshift UV luminosity functions, finding non-monotonic but closed exclusion regions driven by the competition between efficient conversion and rapid depletion of the heavy component. These results show that the internal thermodynamics of a secluded multi-component dark sector can leave observable imprints on structure formation, providing a complementary probe of secluded dark matter.

    ↳ astro-ph.COhep-ph0 citations
24. 24*

    Exact Solutions of the SU(2) Yang-Mills Equations from a Static Ansatz

    Yu-Xuan Zhang🇨🇳 · Jing-Ling Chen🇨🇳

    We present a systematic study of static solutions to the source-free SU(2) Yang-Mills equations, in which the gauge potential explicitly depends on spin operators. By employing the \emph{vector potential extraction approach} -- which requires the total angular momentum operator (orbital plus spin) to satisfy the standard angular momentum algebra -- we derive the most general form of the spin vector potential $\vec{A}$. This leads to the static ansatz $\{\vec{A}=[k_1(\hat{r}\times \vec{\Gamma })+k_2\vec{\Gamma }+k_3(\vec{\Gamma }\cdot \hat{r})\hat{r}]/r,\phi =f_1(r)(\vec{\Gamma }\cdot \hat{r})+f_2(r)\}$, parametrized by three constants $\{k_1,k_2,k_3\}$ and two radial functions $\{f_1(r),f_2(r)\}$. After substituting this static ansatz into the Yang-Mills equations we obtain a set of consistency equations. Solving these equations provides a complete classification of the exact static solutions, including both real and complex families. The known simple SU(2) static solution $\{\vec{A}=\tilde{k}(\hat{r}\times \vec{\Gamma })/r,\phi =\kappa /r\}$ is recovered as a special case. Our classification reveals new static configurations that could be valuable for non-perturbative studies and for models where the internal spin couples to non-Abelian gauge fields.

    ↳ quant-phhep-ph0 citations
25. 25*

    Charmonium radiative transitions to dileptons from lattice QCD: The case of $h_c\to {\eta }_c{\ell }^{+}{\ell }^{-}$ and ${\chi }_{c1}\to J/\psi {\ell }^{+}{\ell }^{-}$

    D. Bečirević🇫🇷 · R. Di Palma🇮🇹 · R. Frezzotti🇮🇹 · G. Gagliardi🇮🇹 · V. Lubicz🇮🇹 · F. Sanfilippo🇮🇹 · N. Tantalo🇮🇹

    We present a lattice QCD study of dilepton production in charmonium transitions, specifically focusing on the $1^{+-}\to 0^{-+}$ and $1^{++}\to 1^{--}$ processes: $h_c\to {\eta }_c{\ell }^{+}{\ell }^{-}$ and ${\chi }_{c1}\to J/\psi {\ell }^{+}{\ell }^{-}$, where $\ell =e,\mu$. The relevant hadronic matrix elements are computed using gauge field configurations generated by the Extended Twisted Mass Collaboration with $N_f=2+1+1$ dynamical Wilson--Clover twisted-mass fermions at four lattice spacings. Simulations are performed at physical dynamical $u$, $d$, $s$, and $c$ quark masses, except for the coarsest lattice, where the lightest sea quark mass corresponds to a slightly heavier pion mass. A controlled continuum extrapolation is carried out. In the continuum limit for the $h_c$ decays, we obtain $\Gamma (h_c\to {\eta }_c{e}^{+}{e}^{-})=5.45(19)\mathrm{keV}$, and $\Gamma (h_c\to {\eta }_c{\mu }^{+}{\mu }^{-})=0.635(22)\mathrm{keV}$. For the ${\chi }_{c1}$ decays, we find: $\Gamma ({\chi }_{c1}\to J/\psi e^{+}{e}^{-})=2.869(90)\mathrm{keV}$, and $\Gamma ({\chi }_{c1}\to J/\psi {\mu }^{+}{\mu }^{-})=0.1993(72)\mathrm{keV}$. Our results for the ${\chi }_{c1}$ decays show good compatibility with experimental data. However, our prediction for the $h_c\to {\eta }_c{e}^{+}{e}^{-}$ decay rate is approximately $3\sigma$ larger than the BESIII result. We also present predictions for the differential decay widths as functions of the dilepton invariant mass, $q^2$, and for angular observables sensitive to longitudinal transition form factors, which are inaccessible in radiative decays with real photon emission. These results constitute the first fully dynamical lattice QCD predictions for dilepton decay rates in $h_c$ and ${\chi }_{c1}$ charmonium transitions, including their differential distributions and angular observables. They provide benchmark predictions for future experimental studies.

    ↳ hep-lathep-phPRD(2026)·1 citation
26. 26*

    Neutrino self-interactions in post-reionization era: Lyman-$\alpha$, 21-cm and cross-spectra

    Sourav Pal🇮🇳 · Supratik Pal

    Neutrino self-interactions delay the onset of free-streaming in the early universe, leaving distinct, scale-dependent signatures on the matter power spectrum. We investigate these signatures in post-reionization 21-cm intensity mapping and the Lyman-$\alpha$ (Ly$\alpha$) forest at redshifts $z\sim 2$--$3.5$, and forecast the constraints achievable with upcoming surveys using Fisher matrix analysis. Modeling neutrino self-interactions through an effective four-fermion parameterization with coupling $G_{\mathrm{eff}}$, we compute modifications to the Ly$\alpha$ and 21-cm auto- and cross-power spectra for both strongly interacting (SI${}_{\nu }$, ${\log }_{10}{G}_{\mathrm{eff}}=-1.77$) and moderately interacting (MI${}_{\nu }$, ${\log }_{10}{G}_{\mathrm{eff}}=-5$) scenarios. We then combine these with forecasts for a representative next-generation cosmic microwave background (CMB) mission to evaluate the capabilities of SKA1-Mid and PUMA. We find that the Ly$\alpha$--21-cm cross-correlation provides a systematics-resilient probe of the interaction signal, and decisively breaks the degeneracy between the primordial scalar power spectrum amplitude ($A_s$) and $G_{\mathrm{eff}}$ that limits CMB only analysis, particularly for the SI${}_{\nu }$ mode. Furthermore, the CMB+PUMA combination emerges as the optimal survey configuration for both regimes, reaching 1$\sigma$ constraints of $\mathcal{O}(10^{-3})$ on $\sigma ({\log }_{10}{G}_{\mathrm{eff}})$ for the SI${}_{\nu }$ mode and $\mathcal{O}(10^{-2})$ for the MI${}_{\nu }$ mode. Compared to the CMB-only baseline, this represents an improvement of approximately one order of magnitude for the SI${}_{\nu }$ mode, and nearly two orders of magnitude for the MI${}_{\nu }$ mode. We show that this conclusion holds uniformly over the full range of coupling strengths from ${\log }_{10}{G}_{\mathrm{eff}}=-6$ to $-1.77$.

    ↳ astro-ph.COhep-phJCAP(2026)·3 citations
27. 27*

    Renormalization and Non-perturbative Dynamics in Conformal Quantum Mechanics

    Jacob Hafjall🇩🇰 · Thomas A. Ryttov🇩🇰

    We study conformal quantum mechanics by first considering the perturbative $S$-matrix in various dimensions. The model has two couplings and we study perturbatively the degree of ultraviolet divergences arising in the interplay between the two couplings. We then focus on the inverse square potential in one spatial dimension and compute the beta function to arbitrarily perturbative and non-perturbative orders. This we do in both the bound state sector and scattering sector. We provide explicit, exact and infinite series results of the first few non-perturbative orders.

    ↳ quant-phhep-phhep-th0 citations
28. 28*

    Inverse Problem in Effective Field Theory

    Francesco Calisto🇺🇸 · Clifford Cheung🇺🇸 · Grant N. Remmen🇺🇸 · Francesco Sciotti🇪🇸 · Michele Tarquini🇺🇸

    We show that the tree-level spectrum of heavy particles can be directly extracted from the Wilson coefficients of the corresponding effective field theory at low energies. This procedure is exact when the number of resonances is finite, and otherwise approximate. Our results are derived from a new class of analytic dispersion relations that depend nonlinearly on the scattering amplitude and apply to an exceedingly broad class of theories and kinematics.

    ↳ hep-thhep-phPRL(2026)·4 citations
29. 29*

    Systematic Analytic Regularization in ${\phi }^4$ and Yukawa Theories

    Jarryd Bath🇿🇦 · W. A. Horowitz🇿🇦

    We introduce a novel regularization scheme: Systematic Analytic Regularization (SAR). SAR regularizes a theory at the level of the action by analytically continuing the power of the kinetic operator, ensuring that the theory is formally finite before any terms in the Dyson series are evaluated. We demonstrate that SAR fully and self-consistently regularizes ${\phi }^4$ and Yukawa theories at NLO.

    ↳ hep-thhep-phnucl-th0 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.