Thu·Jun 11, 2026Thursday·June 11, 2026

1. 01*

   Radiative Neutrino Mass in a Nonholomorphic $T^{\prime }$ Modular Invariant Model

   Mohamed Amin Loualidi🇦🇪 · Mohamed Miskaoui🇲🇦 · Salah Nasri🇦🇪

   The T4-2-i topology provides a one-loop realization of Majorana neutrino mass and may be viewed as a radiative extension of the type-II seesaw, with a scalar triplet, two inert scalar doublets, and singlet fermions propagating in the loop. A central difficulty in realizing this topology lies in the simultaneous presence of tree-level type-I and type-II seesaw contributions arising from the same particle content. In addition, the stability of the dark-matter candidate typically requires the introduction of an ad hoc discrete symmetry. In this work, we revisit the T4-2-i topology within a nonholomorphic modular-invariant framework based on the double-cover group $T^{\prime }$. The presence of both even- and odd-weight polyharmonic Maaß forms considerably enlarges the space of allowed modular structures, while the residual ${\mathbb{Z}}_2$ symmetry associated with the vicinity of the fixed point $\tau =i$ naturally stabilizes the lightest odd state. The modular assignments forbid the dangerous tree-level contributions, determine the flavor structure of the lepton sector, and allow both fermionic and scalar dark-matter candidates. We confront the model with neutrino-oscillation data, charged-lepton-flavor-violating bounds, electroweak precision observables, the Higgs diphoton signal strength, the observed dark-matter relic abundance, the cosmological bound on the sum of neutrino masses, and direct-detection limits. Focusing on the fermionic dark-matter candidate, in which the lightest odd state is the Majorana fermion $N_1$, we find that both normal and inverted neutrino mass orderings remain viable. In the allowed region, the relic abundance is largely controlled by coannihilation with the inert scalar partners, while the spin-independent direct-detection rate remains naturally suppressed because it arises only through a loop-generated Higgs portal.

   hep-ph2 citations
2. 02*

   Correlated Matter Induced Biases in Long-Baseline Neutrino Oscillation Measurements

   Tia Pandit🇮🇳 · Bipin Singh Koranga🇮🇳

   We demonstrate that treating Earth matter effects via a constant-density approximation introduces a fundamental systematic error in long-baseline neutrino oscillation analyses. Using exact numerical propagation through realistic PREM profiles, we show that matter-profile mismodeling does not merely affect the ${\nu }_{\mu }\to {\nu }_e$ appearance probability, but generates correlated biases across the ${\nu }_{\mu }\to {\nu }_{\tau }$ and ${\nu }_{\mu }\to {\nu }_{\mu }$ channels as dictated by PMNS unitarity. Our stochastic analysis reveals that the ${\nu }_{\mu }\to {\nu }_{\tau }$ channel is the most volatile carrier of the geophysical systematic. Across varying correlation lengths at baselines like $5000$ km and $7000$ km, the $\tau$-appearance channel consistently carries a larger mean bias and variance than the standard ${\nu }_{\mu }\to {\nu }_e$ appearance channel. These findings demonstrate that spatially resolved density treatments are a mathematical necessity for the analysis frameworks of future precision neutrino facilities.

   hep-ph0 citations
3. 03*

   Probing TeV-Scale Inverse-Seesaw Leptogenesis and Majorana Dark Matter in $U(1{)}_{B-L}$ Models at Multi-TeV Muon Colliders

   Xin-Qiang Li🇨🇳 · Himadri Roy🇨🇳 · Tripurari Srivastava🇮🇳 · Ya-Dong Yang🇨🇳 · Xing-Bo Yuan🇨🇳

   We investigate a predictive and testable framework in which dark matter (DM), heavy-neutrino dynamics, and the BAU originate from correlated interactions within a local $U(1{)}_{B-L}$ extension of the SM. Unlike conventional $B-L$ constructions based on the type-I seesaw, we employ an inverse-seesaw mechanism realized through a sterile fermion $S_1$ and a complex scalar field $\varphi$, whose vacuum expectation value simultaneously generates the masses of the heavy neutrinos $N_{1,2}$ and the Majorana DM fermion $\chi$ via Yukawa couplings. The small lepton-number-violating parameter induced by a higher-dimensional operator leads to naturally light active neutrinos together with TeV-scale heavy neutrinos and sizable active-sterile mixing, yielding distinctive collider signatures unavailable in minimal $B-L$ models. The relic abundance of $\chi$ is governed by annihilation channels mediated by the same scalar and gauge interactions, producing a direct and model-specific correlation between successful leptogenesis and the observed DM relic density. A combined parameter-space analysis incorporating neutrino oscillation data, lepton-flavor-violating processes, direct-detection limits, and collider bounds on $N_{1,2}$ and $Z^{\prime }$ reveals a narrow yet robust region consistent with all these constraints. Representative benchmark points in this region are examined at a future multi-TeV muon collider. Heavy-neutrino production through electroweak processes yields striking signatures in the dilepton plus missing energy ($2\ell +E{/}_T$) and single-lepton plus di-jet plus missing energy ($1\ell +2j+E{/}_T$) final states. These channels demonstrate that next-generation muon colliders offer a powerful and complementary probe of the inverse-seesaw origin of neutrino masses, the DM relic density, and the TeV-scale leptogenesis within such an extended $U(1{)}_{B-L}$ framework.

   hep-ph1 citation
4. 04*

   Strong First-Order Electroweak Phase Transition and Gravitational Waves in a ${\mathbb{Z}}_4$ Fermion-Scalar Dark Matter Model

   J. P. Carvalho-Corrêa🇧🇷 · J. P. Cunha-Melo🇧🇷 · I. M. Pereira🇧🇷 · B. L. Sánchez-Vega🇧🇷 · A. C. D. Viglioni🇧🇷

   We investigate whether a minimal ${\mathbb{Z}}_4$-symmetric fermion-scalar extension of the Standard Model can simultaneously realise viable dark matter, a strong electroweak phase transition, and a stochastic gravitational-wave signal. The model contains a real scalar singlet and a Dirac fermion, allowing thermal two-component dark matter, mixed WIMP-FIMP histories, and an effectively fermionic relic abundance generated by scalar decays. We impose theoretical consistency, the correct electroweak vacuum, and dark-matter constraints from relic density, direct detection, and invisible Higgs decays before using the surviving points as input for the finite-temperature analysis. This reveals that the compatibility between dark matter and a strong first-order electroweak phase transition is highly selective. After current dark-matter constraints are imposed, the strong-transition criterion along the Higgs direction is satisfied only in two viable regimes: the thermal two-component case with $M_{\psi }<M_S<2M_{\psi }$ and the decay-driven WIMP-FIMP case with $M_S>2M_{\psi }$. By contrast, the thermal regime with $M_S<M_{\psi }$ and the stable mixed WIMP-FIMP scenario with $M_S<2M_{\psi }$ are largely concentrated at small portal couplings or near the Higgs-resonance region, and do not yield a strong transition in the parameter space considered. The successful transitions typically proceed through an intermediate singlet-like phase. For representative nucleating benchmark points in the viable strong-transition regions, we compute the gravitational-wave spectra from sound waves and turbulence. Some spectra enter the projected reach of future space-based interferometers, showing that detectable signals arise only in selected dark-matter-compatible regions where a sufficiently active Higgs portal appears in correlated combination with the scalar mass and the remaining dark sector parameters.

   hep-ph0 citations
5. 05*

   Revisiting the Axial Anomaly and Chiral Magnetic Effect in Dense Matter, with Applications to Axion Dark Matter

   Deog Ki Hong🇰🇷

   We explicitly compute the axial anomaly in dense matter and show that its form remains unchanged from that in vacuum, even in the massless limit. This result follows from a subtle cancellation in the anomalous Ward identity between the medium-induced contributions to the divergence of the axial current and to the pseudoscalar density. We then revisit the chiral magnetic effect in a fermionic medium coupled to an axial chemical potential under an external magnetic field. We show that the medium supports a persistent, conserved anomalous current carried by fermions. The current is determined by the axial chemical potential and suppressed by the Fermi velocity, in agreement with anomalous axial-current correlation functions. We finally discuss applications to axion physics, where axion dark matter acts as an effective axial chemical potential.

   hep-phhep-th1 citation
6. 06*

   Evidence for New $D_s$-Family Molecular States

   Dan Jiang🇨🇳 · Yin Huang🇨🇳 · JiongJiong Zhao🇨🇳

   Motivated by the observed $K{D}^{(\ast )}$ molecular candidates $D_{s0}(2317)$ and $D_{s1}(2460)$, their bottom--strange counterparts, $K{\bar{B}}^{(\ast )}$ molecular states, are naturally expected, although not yet experimentally established. This discrepancy may reflect sizable heavy-quark flavor symmetry breaking, which introduces significant model uncertainties. Current studies of heavy-quark flavor symmetry breaking effects still exhibit strong parameter dependence, and further experimental input is required to constrain these effects, in particular regarding possible additional $K^{(\ast )}{D}^{(\ast )}$ and $K^{(\ast )}{\bar{B}}^{(\ast )}$ molecular states. In this work, we examine whether additional $K^{\ast }{D}^{(\ast )}$ molecular states can be identified among the observed $D_s$ resonances. Within the Gaussian expansion method, we solve the Schrödinger equation using $\sigma$, $\rho$, $\omega$, $\pi$, and $\eta$ exchange potentials, systematically including $S$-wave and higher partial waves. We find that $D_{s1}(2700)$ can be interpreted as a pure $P$-wave $D{K}^{\ast }$ molecule, while $D_{s1}(2860)$ and $D_{s3}(2860)$ are well described as $D^{\ast }{K}^{\ast }$ molecular states dominated by the ${}^1{P}_1$ and ${}^5{P}_3$ components, respectively. We also predict additional molecular states with various $J^P$ quantum numbers. These results provide a new description of the charmed-strange spectrum, and once confirmed will provide additional input data for studies of heavy-quark flavor symmetry breaking effects.

   hep-phhep-th1 citation
7. 07*

   Matching of perturbative and exponentiated initial state radiation corrections to $e^{+}{e}^{-}$-annihilation

   Andrej Arbuzov🇷🇺 · Uliana Voznaya🇷🇺

   The behavior of higher-order radiative corrections due to initial state radiation in processes of electron-positron annihilation is analyzed. Numerical results for energies of future colliders are presented. Uncertainties of the known results on these corrections are estimated. A modified scheme for simultaneous exponentiation of pure photonic and non-singlet pair corrections is presented. Matching of the exponentiated results with the existing analytic higher-order calculations is constructed. A new DIS-like subtraction scheme is discussed.

   hep-ph0 citations
8. 08*

   Nonexistence of hidden-charm pentaquarks in $J/\psi$ photoproduction

   Samson Clymton🇰🇷 · Sang-Ho Kim🇰🇷 · Hyun-Chul Kim🇰🇷

   We investigate $J/\psi$ photoproduction off the proton, $\gamma p\to J/\psi p$, to elucidate the nonexistence of hidden-charm pentaquark signals reported by the GlueX and CLAS12 experiments. Within a coupled-channel rescattering mechanism, we employ the transition amplitudes from a previous coupled-channel analysis that dynamically generates the $P_{c\bar{c}}$ states. The kernel amplitudes for the transition to the $J/\psi N$ channel include both $t$-channel heavy-meson exchange and $u$-channel heavy-baryon exchange. We find that the rescattering contributions from the ${\bar{D}}^{(\ast )}{\Sigma }_c$ channels -- indispensable for the formation of the $P_{c\bar{c}}$ resonances -- are about one order of magnitude smaller than those from ${\bar{D}}^{(\ast )}{\Lambda }_c$, since $g_{{\bar{D}}^{(\ast )}N{\Sigma }_c}$ is roughly five times smaller than $g_{{\bar{D}}^{(\ast )}N{\Lambda }_c}$. Since the $P_{c\bar{c}}$ resonances couple to the $J/\psi N$ channel predominantly through the ${\bar{D}}^{(\ast )}{\Sigma }_c$ intermediate states, their suppression prevents the pentaquark signal from appearing in photoproduction. With only a single parameter controlling the overall normalization, the present work describes the GlueX and CLAS12 cross sections well. These results suggest that the null result from photoproduction need not be in conflict with the pentaquark signals observed by the LHCb Collaboration.

   hep-phhep-exnucl-exPRD(2026)·1 citation
9. 09*

   Final-state rescattering mechanism of doubly-charmed baryon decays: ${\mathcal{B}}_{cc}\to {\mathcal{B}}_{c}V$

   Xiao-Hui Hu🇨🇳 · Fu-Sheng Yu🇨🇳 · Ye Xing🇨🇳

   We study the non-leptonic weak decays of doubly charmed baryons (${\mathcal{B}}_{cc}$) into singly charmed baryons (${\mathcal{B}}_c$) and vector mesons ($V$), denoted as ${\mathcal{B}}_{cc}\to {\mathcal{B}}_{c}V$. The short-distance contributions are calculated within the naive factorization hypothesis, while the long-distance final-state interaction effects are modeled via hadronic triangle diagrams. Unlike previous approaches, which compute only the imaginary part using the Cutkosky cutting rule, we evaluate the complete loop integrals to obtain both the real and imaginary parts of the amplitudes. These provide the nontrivial strong phases essential for CP violation. The model parameters are determined using experimental data. With this improved calculation method, we predict the branching ratios and decay asymmetry parameters for various decay channels, as well as $CP$ violations for short-distance dominated and singly Cabibbo-suppressed channels. This strengthens our theoretical framework for future study of doubly charmed baryons. Certain decays, primarily driven by long-distance effects, have been calculated; their observation in future experiments could help clarify the role of final-state interactions in charm baryon decays. Therefore, our calculation of ${\mathcal{B}}_{cc}\to {\mathcal{B}}_{c}V$ provides crucial predictions for branching ratios, decay asymmetry parameters, and $CP$ violation, which are essential for guiding experimental study at LHCb.

   hep-ph2 citations
10. 10*

    Femtoscopy-driven searches for saturated gluonic matter in inclusive photonuclear processes

    S. Ragoni🇺🇸 · P. Chakraborty🇵🇱 · A. Kisiel🇵🇱 · G. Kornakov🇵🇱 · S. Pulawski🇵🇱

    We present femtoscopy as a new way to search for saturated gluonic matter in inclusive photonuclear processes, such as inclusive ultraperipheral collisions at the Large Hadron Collider (LHC) and the inclusive photonuclear reactions at the Electron-Ion Collider (EIC). As the femtoscopic approaches are sensitive to the space-time structure of the particle emitting source, they are ideal in providing insights also about the initial stage of the collision, where the gluon distributions may impact the effective size of the dipole the quasireal photons oscillate into. This technique demonstrates its capabilities in isolating nuclear shadowing and gluon saturation effects. Finally, we show how a femtoscopic approach is highly sensitive to sub-fermi scale structures typically observed in ultraperipheral collisions, such as gluonic hot spots.

    hep-ph0 citations
11. 11*

    Heavy fermionic dark matter in a secluded $Z_4$ framework

    XinXin Qi🇨🇳 · Hao Sun🇨🇳

    We investigate heavy Majorana dark matter $\chi$ in a secluded scalar sector with a spontaneously broken $Z_4$ symmetry. The symmetry forbids a bare Majorana mass, providing a dynamical origin for the dark matter mass, while a residual $Z_2$ symmetry ensures its stability. We find that the thermal relic abundance can be predominantly determined by the secluded annihilation process $\chi \chi \to h_2{h}_2$ , where $h_2$ is the new heavy Higgs boson. The dominant annihilation process is p-wave suppressed at low velocities, leading to a strong suppression of the present-day annihilation rate relative to that at freeze-out. Consequently, the model can accommodate a heavy thermal dark matter candidate with highly suppressed indirect-detection signals while retaining potentially testable signatures in direct-detection experiments.

    hep-ph0 citations
12. 12*

    Improving the Angular Resolution of IBD Events Using Neutron Capture Information in Super-Kamiokande

    Qishan Liu🇨🇳 · Kenny C. Y. Ng🇨🇳

    One of the most important neutrino interactions is the Inverse Beta Decay (IBD). However, the IBD events typically carry no directional information in water Cherenkov detectors as the positron directions are mostly isotropic at low energies, such as those in supernova studies. As Gadolinium is being added to Super-Kamiokande, the improved neutron capture efficiency not only allows better background rejection, but the neutron capture information could potentially provide additional information that allows better event reconstruction. Due to neutron diffusion in water, event-by-event reconstruction is difficult. However, if the final neutron capture position is correlated with the initial neutrino momentum, it may be possible that neutrino directionality could be reconstructed statistically, with or without using the positron information. In this work, we use Geant4 to simulate neutron propagation in water. We show that in a wide range of neutrino energies from about 10 MeV to several hundred MeV, neutron capture information could statistically enhance the neutrino directionality, compared to positron-only inference, even with neutron diffusion considered. However, practical application of this technique depends crucially on detection effects, especially the vertex reconstruction resolutions. Our work therefore motivates developments of better reconstruction algorithms and techniques, as well as detector upgrades.

    hep-ph0 citations
13. 13*

    Factorizing quarkonium LDMEs and TMDSTFs using effective field theory

    Marston Copeland🇺🇸

    We use effective field theory to factorize production matrix elements that appear in the NRQCD framework for quarkonium cross sections. By applying a Hubbard-Stratonovich transformation and appropriate field redefinitions, we show that the soft and ultrasoft sectors of NRQCD can be decoupled from the heavy quark and antiquark fields in a hybrid vNRQCD/pNRQCD Lagrangian at leading order in the velocity power-counting. This enables us to re-factorize quarkonium production matrix elements in terms of matrix elements of color-singlet composite fields, which we can write as the wave-function at the origin, and state independent vacuum correlators of chromo-electric and chromo-magnetic gluon fields. This approach verifies powerful relationships between the LDMEs of different S-wave quarkonia originally derived using pNRQCD. Additionally, it allows us to derive new relationships for the production matrix elements used in the transverse momentum dependent factorization (TMD) framework, known as TMD soft transition functions, providing a much stronger set of constraints on these nonperturbative operators. This work significantly advances our understanding of quarkonium production, particularly in the TMD framework.

    hep-phhep-thnucl-th1 citation
14. 14*

    The KSVZ Atlas: A Unified SMEFT-ALP Framework

    Ajdin Palavrić🇪🇸 · Xavier Ponce Díaz🇨🇭 · Hector Tiblom🇨🇭

    We develop a general framework for matching KSVZ-like ultraviolet completions featuring vector-like fermions and a spontaneously broken $\mathrm{U}(1{)}_{\mathrm{PQ}}$ symmetry onto the Standard Model Effective Field Theory and the low-energy axion-like particle effective theory. The framework applies to arbitrary vector-like fermion representations and PQ-charge assignments, and systematically captures the effective interactions generated in both sectors. We then perform a comprehensive phenomenological analysis of the resulting SMEFT operators, based on global fits to electroweak precision, Higgs, and flavor observables, obtaining robust bounds on the corresponding Wilson coefficients that are largely independent of the details of the ultraviolet realization. These constraints can subsequently be translated into the QCD axion and ALP parameter space, providing indirect probes of ALP couplings. We further investigate several representative examples of the interplay between the SMEFT and ALP sectors, illustrating how direct ALP searches and indirect precision and flavor observables provide complementary information on the same underlying dynamics. We find that, over large regions of parameter space, indirect constraints derived from the SMEFT analysis dominate over direct ALP probes, except in scenarios where the PQ-charge assignment permits mass mixing with Standard Model fermions. Overall, our results establish a unified framework for connecting ultraviolet completions, SMEFT analyses, and ALP searches, enabling both the interpretation of existing constraints and the exploration of future signals within a common theoretical setting.

    hep-ph5 citations
15. 15*

    ${\mathbf{\chi }}_{\mathbf{c}1}(3872)$ and its Partners in the Diabatic Born-Oppenheimer Approximation for QCD

    Fareed Alasiri🇺🇸 · Eric Braaten🇺🇸 · Roberto Bruschini🇺🇸

    In the Born-Oppenheimer approximation for QCD, the exotic hidden-charm tetraquark meson ${\chi }_{c1}(3872)$ is a near-threshold bound state in Born-Oppenheimer potentials associated with an isospin-0 adjoint meson. The ${\chi }_{c1}(3872)$ is the $1^{++}$ member of a heavy-quark spin-symmetry multiplet whose other members have $J^{PC}$ quantum numbers $0^{++}$, $1^{+-}$, and $2^{++}$. We introduce a simple model for the Born-Oppenheimer potentials that interpolates between the adjoint-meson potential at short distances and the triplet-meson-pair potential at large distances. We take into account the spin splittings of charm mesons nonperturbatively for the first time by solving the diabatic Schrödinger equation. We also take into account the spin splittings of the adjoint meson as well as a narrow avoided crossing with the quarkonium potential. We tune the energy of ${\chi }_{c1}(3872)$ to the $D^{\ast }\bar{D}$ threshold and then calculate the spin splittings of the other members of the multiplet and their decay widths into charm-meson pairs. We also calculate the energies and decay widths of the corresponding multiplet of hidden-bottom tetraquarks. These calculations provide a template for the quantitative analysis of all hidden-heavy hadrons using the Born-Oppenheimer approximation for QCD.

    hep-ph1 citation
16. 16*

    Sensitivity to top-quark couplings in diboson production at lepton colliders

    Eugenia Celada🇬🇧 · Víctor Miralles🇪🇸 · Eleni Vryonidou🇨🇾

    We study the next-to-leading order electroweak corrections to $e^{+}{e}^{-}\to W^{+}{W}^{-}$ from dimension-six two-fermion top-quark operators in the Standard Model Effective Field Theory. We compute analytical and numerical results for future electron-positron colliders, focusing on the proposed LEP3 and FCC-ee that will operate at centre-of-mass energies below the $t\bar{t}$ production threshold. We compare the indirect sensitivity arising from virtual corrections to $WW$ production to that from $ZH$ production, and to the current constraints from LEP and LHC data. We show that NLO corrections can provide competitive sensitivity to these operators. This work represents a first step towards the systematic computation of electroweak corrections to $W$-pair production at lepton colliders in the SMEFT, whose impact can then be properly assessed in global analyses.

    hep-ph0 citations
17. 17*

    The Fundaments of Unity: $\mathcal{O}(1)$ Couplings in Quantum Field Theories

    Ben Allanach (Cambridge U., DAMTP)🇬🇧

    We critically examine the expectation that in a fundamental quantum field theory, dimensionless couplings in the Lagrangian density should all be of order unity. We propose a measure to quantify the adherence of a theory to this: the spread (the ratio of the largest to the smallest of the magnitudes) of such dimensionless couplings, obtaining various closed-form results. If we take independent and identically distributed (IID) couplings to parameterise our uncertainty on the values of the order-unity couplings, the spread can be much larger than one might naively expect. For a theory with 20 IID unit normal couplings, the probability that the spread is greater than 100 is 0.29, for example. Even when the IID couplings have exponentially suppressed tails, the distribution of the spread has fat power-law tails whose amplitude grows with the number of independent couplings.

    hep-phhep-thphysics.data-anPLB(2026)·1 citation
18. 18*

    Collective neutrino oscillations: Many-body non-forward effects and non-classicality

    Julien Froustey🇪🇸 · Ermal Rrapaj🇺🇸 · Yuhao Liu🇺🇸 · Gushu Li🇺🇸 · Costin Iancu🇺🇸 · Vincenzo Cirigliano🇺🇸

    Neutrino evolution in dense astrophysical environments is typically described either within a quantum kinetic framework, which neglects the build-up of multi-body correlations, or through simplified many-body calculations that allow significant entanglement to develop. In this work, we compare these two approaches in a simple neutrino-gas configuration, with particular emphasis on the role of non-forward scattering processes. These effects are incorporated either through a collision term in the kinetic description, or by considering the full neutrino-neutrino many-body Hamiltonian. We highlight differences between the two descriptions in both their characteristic timescales and asymptotic behavior. Motivated by the natural suitability of quantum computing for many-body calculations, we further investigate the non-classicality of neutrino evolution, discussing Trotter error scaling, along with the associated costs of constructing quantum circuits in terms of entangling gates and non-Clifford gates. We find that the resources needed for neutrino many-body evolution are on the low end of typical high-energy physics problems and on the mid to high end with respect to quantum chemistry problems. For the full Hamiltonian, resource requirements increase relative to the truncated version. We emphasize the importance of efficient fermion-to-qubit encodings, which are essential for reducing the substantial computational resources required for such simulations.

    hep-phastro-ph.HEquant-ph2 citations
19. 19*

    When direct detection constrains reheating temperature: freeze-in with stronger couplings and inflaton-seeded freeze-in

    Xavier Bertou🇫🇷 · Olivier Deligny🇫🇷 · Mathieu Gross🇫🇷 · Yann Mambrini🇫🇷 · Issam-Eddine Mellouki🇫🇷

    Recent results from the DAMIC-M and PandaX collaborations have excluded the standard freeze-in production of dark matter for masses in the range $3\mathrm{MeV}\lesssim m_{\chi }\lesssim 1\mathrm{GeV}$ in the context of extensions of the Standard Model featuring an additional ultra-light $U(1{)}_{\mathrm{X}}$ gauge boson. In this work, we analyze the constraints induced by DAMIC-M and PandaX results on the reheating temperature in freeze-in models at stronger coupling, or when a non-thermal source (such as inflaton decay) comes into play. We identify viable scenarios in which the DM relic abundance is correctly reproduced while evading current experimental bounds on the electron-scattering cross section, ${\overline{\sigma }}_{\mathrm{e}}$. In particular, we show that for reheating temperatures below the electroweak scale, Boltzmann suppressed production can be compensated by stronger couplings, bringing freeze-in scenarios within present experimental reach. Finally, we study a hybrid scenario in which a small branching ratio of inflaton decay seeds a nonzero initial dark-matter abundance. We show that such contributions can significantly modify freeze-in predictions across broad regions of parameter space, offering an additional pathway for probing extremely feeble interactions.

    hep-phastro-ph.CO3 citations
20. 20*

    The Residual $288$ of the $E_8\times \omega E_8$ Program as Adjoint-Lineage Scaffolding Labels: an Ontology, and the Status of the Bifermionic Lagrangian

    Tejinder P. Singh🇮🇳

    In the $E_8\times \omega E_8$ octonionic unification program, each $E_8$ branches as $SU(3{)}_{st}\times E_6$, supplying one geometric $SU(3{)}_{st}$ per branch, while the split-complex unit $\omega$ grades the visible and pre-gravitational branches; matter and gauge content is carried by $E_6\times E_6$, with chiral fermions realized as Cl(6) minimal-ideal spinors rather than $E_8$ representation components -- which places the chiral sector outside the Distler-Garibaldi no-go theorem. Comparing the 496-label two-branch adjoint reservoir with the 208 structures matched in the Generalized Trace Dynamics Lagrangian leaves a residual 288. We argue that this 288 is an adjoint-lineage representation-label ledger -- bookkeeping for the scaffolding -- and not a particle spectrum. The bifermionic seed is Hermitian, with $E_6$-covariant channels classified by $\overline{27}\otimes 27=1\oplus 78\oplus 650$: each branch's 78 supplies the gauge currents and a composite electroweak doublet, while the $E_6$ singlet is electroweak-inert. The charge-sum sector A is absent from the bare seed, and the 252 $SU(3{)}_{st}$-charged labels cannot be matter bilinears in any reservoir, conditional on the spinor ontology. The size of $E_8\times \omega E_8$ is thus the dimension of a label ledger, not a count of particles; beyond the Standard Model, the framework's content is sterile neutrinos and a second composite scalar.

    hep-phhep-th2 citations
21. 21*

    Constraining the real scalar singlet extension of the SM

    Moritz Bosse🇩🇪 · Gudrun Hiller🇩🇪 · Daniel Litim🇬🇧 · Fabio Maltoni🇧🇪 · Michael J. Ramsey-Musolf🇨🇳 · Simone Tentori🇧🇪 · Guotao Xia🇨🇳

    The real scalar singlet extension of the standard model provides a minimal framework in which the Higgs sector can realise a strong first-order electroweak phase transition and improve the stability of the electroweak vacuum. We combine the electroweak phase transition and high-scale vacuum stability with current and projected collider probes, including precision Higgs measurements, the Higgs trilinear coupling, EWPO and resonant searches for a heavy singlet-like scalar in $ZZ$ and di-Higgs final states. Focusing on a singlet heavier than the standard model Higgs, we find that there is parameter space compatible with a strong first-order electroweak phase transition for singlet-like scalar masses up to nearly 1 TeV. Deviations in the Higgs self-coupling can be larger than those in the Higgs--$Z$ coupling, making Higgs-potential measurements a key probe. We find that the HL-LHC will test a large fraction of the parameter space, while the FCC will provide ultimate discovery and model-discrimination capabilities.

    hep-phhep-ex5 citations
22. 22*

    Directional dark matter signatures of the Large Magellanic Cloud

    Javier Reynoso-Cordova🇮🇹 · Nassim Bozorgnia🇨🇦 · Marie-Cécile Piro🇨🇦

    The Large Magellanic Cloud (LMC), the most massive satellite of the Milky Way (MW), can significantly perturb the local dark matter (DM) distribution. We study its impact on directional DM detection using the Auriga cosmological simulations of a MW analogue hosting an LMC analogue. We find that the LMC induces strong anisotropies in directional recoil signals, driven primarily by the non-zero mean azimuthal velocity of the local DM distribution. The characteristic ring-like feature predicted in the Standard Halo Model (SHM) for heavy DM and low recoil energies is strongly distorted, producing an asymmetric recoil pattern concentrated at preferred azimuthal angles. Differences between recoil maps for the MW-LMC analogue and the SHM reach up to $\sim 80\%$ near the signal maximum. These distortions significantly enhance directional discovery prospects, reducing the number of events required to reject isotropy by nearly a factor of five for a 100 GeV DM particle in a near-future CYGNUS-like experiment, and by even larger factors for heavier DM. Our results highlight the importance of the LMC for interpreting and optimizing future directional DM searches.

    hep-phastro-ph.COastro-ph.GA0 citations
23. 23*

    Polarization Formalism for Photon-Gravitational Wave Mixing Around Magnetars

    Jean-Simon Côté🇨🇦 · Jean-François Fortin🇨🇦

    The Gertsenshtein effect can be used to probe the stochastic gravitational wave background at high frequencies, well above the range of standard cosmological sources. In this paper, we revisit the conversion between electromagnetic and gravitational waves in the magnetosphere of magnetars by solving the evolution equations of the associated Stokes parameters. In the process, we point out that the adiabatic approximation usually taken in the literature is not generally justified in the context of the Gertsenshtein effect. To derive analytical results, we focus our attention on two specific geometries where the adiabatic approximation is valid. From these, we derive a lower bound on the stochastic gravitational wave background from the conversion of magnetar electromagnetic emission into gravitational waves, and an upper bound by requiring that the conversion of background gravitational waves into electromagnetic radiation does not exceed the observed magnetar flux in the X-ray band. Our results demonstrate that gravitational waves generated through the Gertsenshtein conversion of magnetar electromagnetic emission produce a negligible stochastic background, as anticipated.

    hep-phhep-th0 citations
24. 24*

    CMB Constraints on Pre-Inflationary Axion Dark Matter Isocurvature

    Catherine Petretti🇺🇸 · Praniti Singh🇺🇸 · Matteo Braglia🇺🇸 · Xingang Chen🇺🇸 · JiJi Fan🇺🇸 · Lingfeng Li🇨🇳

    Although measurements of the Cosmic Microwave Background (CMB) are consistent with a nearly scale-invariant primordial spectrum of adiabatic perturbations, in which the energy densities of different components (radiation, baryons, and dark matter) fluctuate proportionally, there could also exist isocurvature perturbations, in which density fluctuations of the individual components differ from the adiabatic mode. Cold dark matter isocurvature (CDI) perturbations with a variety of spectral tilts generated in pre-inflationary axion models provide one such example. In this article, we present the most updated constraints on these axion CDI perturbations using the latest CMB anisotropy measurements from Planck, the Atacama Cosmology Telescope (ACT), and the South Pole Telescope (SPT). We study both fixed spectral indices with values ranging from red- to blue-tilted spectra as well as the case with a free index. We find that the constraint on the spectral index gets moderately improved with the combined datasets compared to Planck alone, while the bounds on the isocurvature amplitudes for the fixed spectral indices we consider do not get tighter. We also discuss the theoretical implications of our constraints, in particular for models giving rise to blue-tilted spectra.

    ↳ astro-ph.COhep-ph3 citations
25. 25*

    Lectures on Semiclassical Methods for Composite Operators

    Francesco Sannino🇩🇰

    These lecture notes are intended as a coherent introduction to conformal field theory in general, and composite operators in particular, through a semiclassical framework for computing scaling dimensions, with emphasis on operators of the form ${\varphi }^n$. In doing so, they aim to fill a gap in the literature and to help decode some of the relevant concepts. The physical idea is that at large $n$ an (heavy) operator creates a highly occupied state. Through the state-operator correspondence, this state lives on the cylinder $\mathbb{R}\times S^{d-1}$, and its scaling dimension is the corresponding energy of the theory on the cylinder. The notes are organized as a self-contained route from conformal symmetry to semiclassical dynamics. Part I reviews the conformal group, primary operators, radial quantization, the state-operator correspondence, and operator mixing. Part II builds the semiclassical framework, first in the free scalar theory, where the dimension of ${\varphi }^n$ is recovered in three independent ways, and then through the double-scaling limit, the action variable, and Bohr-Sommerfeld quantization. Part III develops the general machinery of periodic saddles, Floquet theory, fluctuation determinants, the Gel'fand-Yaglom method, and the Gutzwiller trace formula. Part IV applies the framework to the $O(N)$ ${\varphi }^4$ theory in $d=4-ϵ$ at the Wilson-Fisher fixed point, deriving the classical elliptic solution, the Lamé fluctuation spectrum, the zero modes, and the one-loop contribution to the large-$n$ scaling dimensions. Beyond the explicit computation, the notes emphasize the role of composite operators as probes of collective sectors of quantum field theory, with extensions to gauge theories, conformal windows, and asymptotically safe field theories.

    ↳ hep-thcond-mat.otherhep-lathep-ph0 citations
26. 26*

    Polarized Nuclear DVCS at the EIC

    Jackson R. Pybus🇺🇸 · Xuan Li🇺🇸 · Liliet Calero-Diaz🇺🇸

    The Electron-Ion Collider (EIC) will enable a series of measurements at unprecedented energies and luminosities, providing new opportunities to investigate the microscopic structure of nucleons and nuclei at small $x_B$. Exclusive processes such as Deeply Virtual Compton Scattering (DVCS) offer unique access to the three-dimensional structure of hadrons through Generalized Parton Distributions (GPDs), while polarized electron and ion beams further enable detailed studies of spin-dependent structure. A model for coherent DVCS on polarized ${}^3$Heis developed and applied to simulations of for $9\times 166$-GeV $e^3$He collisions at the EIC. Using this framework, the statistical precision achievable is estimated for measurements of beam-spin asymmetries and for the extraction of the Compton Form Factors (CFFs) ${\mathcal{H}}_{{}^3\mathrm{He}}$ and ${\tilde{\mathcal{H}}}_{{}^3\mathrm{He}}$. Early EIC data are found to enable precise differential measurements of the unpolarized CFF ${\mathcal{H}}_{{}^3\mathrm{He}}$ and to provide significant constraints on its real and imaginary components. By contrast, meaningful constraints on the polarized CFF ${\tilde{\mathcal{H}}}_{{}^3\mathrm{He}}$ require substantially larger integrated luminosities. The kinematics of the recoil ${}^3$He nucleus are also examined, and the far-forward detector capabilities at the EIC required to tag the intact nucleus and perform fully exclusive measurements of coherent nuclear DVCS are discussed.

    ↳ nucl-exhep-phnucl-th0 citations
27. 27*

    Application of the Skyrme Hartree-Fock-Bogoliubov Theory to WIMP-Nucleus Interactions in 40Ar

    N. Krishnan🇦🇺 · R. Abdel Khaleq🇦🇺 · C. Simenel🇦🇺

    WIMP scattering from 40Ar is investigated using a self-consistent Skyrme Hartree-Fock-Bogoliubov (HFB) approach. Nuclear form factors relevant to dark matter direct detection are calculated from the resulting one-body density matrix elements and compared with shell-model predictions. Good agreement is found for the spin-independent response, while significant differences are observed for the spin-orbit response due to variations in single-particle occupancies. The effects of particle-number projection are shown to be small for 40Ar. These results demonstrate the sensitivity of certain dark matter response channels to the underlying nuclear structure model and establish a framework for extending mean-field calculations to nuclei beyond the reach of large-scale shell-model studies.

    ↳ nucl-thhep-ph0 citations
28. 28*

    Nonminimal couplings and preheating effects in $R^2$-Higgs inflation after ACT and SPT

    Haneesh Gonuguntla🇮🇳 · Tanmoy Modak🇮🇳 · Arnab Samanta🇮🇳

    We study the effects of dimension-four and dimension-six nonminimal Higgs couplings to the Ricci scalar $R$ in the $R^2$-Higgs inflation model in light of the recent ACT and SPT observations. We show that the dimension-six operators $|\Phi {|}^2{R}^2$ and $|\Phi {|}^{4}R$ can accommodate the enhanced scalar spectral index $n_s$ preferred by the combined CMB+BAO analyses. Using a doubly covariant formalism, we find that the same region of parameter space that explains the observed value of $n_s$ can also induce rapid preheating through the production of the Goldstone modes. If thermalization proceeds efficiently through this preheating mechanism, it may help match the inflationary scale with the CMB reference scale.

    ↳ astro-ph.COgr-qchep-ph3 citations
29. 29*

    Hidden-sectors search and probe of discrete symmetries at the REDTOP experiment

    REDTOP COllaboration

    The $\eta$ and ${\eta }^{\prime }$ mesons are nearly unique in the particle universe since they are nearly Goldstone bosons, and their decay dynamics are strongly constrained. While earlier experiments collected samples of order $\sim 10^9$ $\eta$, the proposed REDTOP (Rare Eta Decays To Observe Physics Beyond the Standard Model) facility targets $\mathcal{O}(10^{14})$ $\eta$ and $\mathcal{O}(10^{12})$ ${\eta }^{\prime }$, enabling broad searches for physics beyond the Standard Model. In this work, we present studies evaluating REDTOP sensitivity to processes that couple the Standard Model to New Physics through four portals: the Vector (dark photon), the Scalar (Higgs-mixing), the Axion-like, and the Heavy Lepton. In parallel, the proposed statistics allow precise tests of $CP$ and $T$ invariance and lepton universality and improve determinations of the $\eta /{\eta }^{\prime }$ transition form factors, which are crucial inputs to the hadronic light-by-light contribution to the muon anomalous magnetic moment $(g-2{)}_{\mu }$.

    ↳ hep-exhep-ph1 citation
30. 30*

    Black Hole Radiation Sparsity and Bekenstein Entropy Loss in Non-Commutative Schwarzschild Spacetime

    Abdellah Touati

    In this paper, we investigate the sparsity of black hole radiation, the Bekenstein entropy loss, and the total particle emission of a Schwarzschild black hole (SBH) within the framework of non-commutative (NC) gauge theory of gravity. First, we provide a brief review of black hole (BH) thermodynamics, computing both the deformed Hawking temperature and entropy. In this geometry, the divergent behavior of the temperature is removed, and a logarithmic correction to the entropy emerges. We then present the NC corrections to the Bekenstein entropy loss of the SBH alongside the total number of emitted particles. Our results show that the total number of emitted particles is proportional to the entropy behavior of the NC SBH, which is consistent with non-thermal radiation. Finally, we analyze the sparsity of Hawking radiation in this geometry, finding that the NC SBH exhibits extremely sparse radiation ($\hat{\eta }\gg 1$), which diverges at the final stage of evaporation as the black hole ceases to radiate.

    ↳ gr-qchep-phhep-th0 citations
31. 31*

    Localization of Chiral Electromagnetic Waves on Thick Axion Domain Walls

    Nemanja Kaloper🇺🇸

    We analyze Maxwell theory coupled to an axion domain wall as a spectral boundary value problem. We find that a finite-width axion domain wall generically supports a localized normalizable chiral electromagnetic mode with linear, gapless dispersion. This mode arises from helicity-dependent coupling sourced by the axion gradient: one polarization experiences an effective attractive potential and forms a bound state, while the opposite polarization is repelled. The existence of this chiral surface photon is robust over a wide regime of wall structures and axion masses. Our result shows that axion domain walls generically support a localized chiral photon that has been missed in previous analyses.

    ↳ hep-thastro-ph.COcond-mat.mes-hallhep-ph+11 citation
32. 32*

    Observing Cosmic Reheating with the expanded Simons Observatory

    Lei Ming🇨🇳 · Marco Drewes🇧🇪

    The Simons Observatory will be extended by three Small Aperture Telescopes by 2027, increasing the total number of these instruments to six. We study the prospects for probing the reheating temperature and the inflaton coupling with this configuration, assuming a discovery of primordial gravitational waves in benchmark scenarios with a tensor-to-scalar ratio r=0.0036 or r=0.01. In popular plateau models of inflation, such an observation would fix the scale of inflation and enable determination of the order of magnitude of the reheating temperature and the inflaton interactions. For QCD-driven Warm Inflation the reheating temperature and inflaton coupling to gluons could, under optimistic assumptions, be measured with a precision of a few percent. Such a measurement would imply a clear prediction for complementary inflaton searches in axion experiments, paving the way toward probing the mechanism responsible for the initial conditions of the hot Big Bang in the laboratory.

    ↳ astro-ph.COhep-ph0 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.