Thu·Dec 4, 2025Thursday·December 4, 2025

1. 01*

   Effective Field Theory Perspective On King Non-linearity

   Benoît Assi🇺🇸 · Sam Carey🇺🇸 · Sebastian Jäger🇬🇧 · Gabriel Lee🇨🇦 · Gil Paz🇺🇸 · Gilad Perez🇮🇱 · Jure Zupan🇺🇸

   Precision spectroscopic measurements of isotope shifts have recently reached a high level of accuracy. Tests of King non-linearity (NL) along isotope chains have been proposed as a tool to search for fifth-force mediators. At the same time, these tests can potentially teach us about the structure of heavy nuclei at unprecedented precision, where King NL has already been observed in several systems. A robust interpretation of the existing data, however, is hampered by incomplete control over the Standard Model (SM) contributions. We develop a systematic effective field theory framework, matching the SM onto scalar non-relativistic QED in the infinite nuclear mass limit and then onto quantum-mechanical potentials. This approach organizes all nuclear effects into a small set of Wilson coefficients and cleanly separates short- and long-distance physics. We show that the commonly used treatment of the $⟨r^2{⟩}^2$ term needs to be reconsidered, as it arises only at second-order in perturbation theory, and we derive the long-range $1/r^4$ potential from nuclear polarizability. Applying the framework to hydrogen-like systems, we provide a transparent classification of SM sources of King NL relevant for current and future isotope-shift experiments. The formalism can be applied to learn about the shape of the heavy scalar nuclei at a higher level of precision and detail than what was previously attainable.

   hep-phnucl-thphysics.atom-ph1 citation
2. 02*

   New physics in toponium's shadow?

   Thomas Flacke🇰🇷 · Benjamin Fuks🇫🇷 · Dongchan Kim🇰🇷 · Jinheung Kim🇰🇷 · Seung J. Lee🇰🇷 · Léandre Munoz-Aillaud🇫🇷

   ATLAS and CMS have recently reported enhancements in the top-antitop production rate near threshold, a region where non-perturbative QCD dynamics associated with toponium formation become relevant. We investigate how this behaviour is modified in the presence of a neutral pseudoscalar that couples to gluons and top quarks, using an effective description that consistently incorporates perturbative Standard Model and new physics contributions, their interference and non-perturbative threshold effects. We show that the combined effect of those ingredients markedly shapes the viable region of the pseudoscalar parameter space, particularly for narrow resonances with masses close to twice the top mass. While Standard Model threshold effects could explain a sizeable part of the measured enhancements, the current data remain compatible with additional contributions from pseudoscalar interactions.

   hep-phhep-exPLB(2026)·9 citations
3. 03*

   NNLO+NNLL Predictions for Heavy-Jet Mass and C-parameter in Higgs Decays to Quarks and Gluons

   Elliot Fox🇬🇧 · Aude Gehrmann-De Ridder🇨🇭 · Thomas Gehrmann🇨🇭 · Nigel Glover🇬🇧 · Matteo Marcoli🇬🇧 · Christian T. Preuss🇩🇪

   We consider the resummation of large logarithmic corrections arising in the two-particle limit at next-to-next-to-leading logarithmic (NNLL) accuracy for the heavy-jet mass and $C$-parameter distributions in the decay of a Higgs boson to quarks and gluons: $H\to b\bar{b}$, $H\to c\bar{c}$, and $H\to gg$. We demonstrate how the matched NNLO+NNLL results clarify the relative contributions of key hadronic Higgs-decay channels ($H\to b\bar{b}$, $H\to c\bar{c}$, $H\to gg$) yielding reduced uncertainties for both event-shape observables -- especially for heavy-jet mass -- while revealing substantial effects that shift the $C$-parameter peak in gluonic decays.

   hep-phPLB(2026)·2 citations
4. 04*

   Lepton number violation from Higgs/$Z$ decays into a pair of right-handed neutrinos

   Arindam Das🇯🇵 · Takaaki Nomura🇨🇳 · Kei Yagyu🇯🇵

   We explore signatures of Lepton Number Violation (LNV) from decays of the discovered Higgs ($h$) and Z bosons into a pair of Right-Handed Neutrinos (RHNs). Due to the Majorana nature of RHNs, the final state can be the same-sign dilepton plus jets leading to 2 units of LNV. As a simple but plausible scenario, we investigate such a signal in models with a new $U(1{)}_X$ gauge symmetry which naturally introduces three RHNs for gauge anomaly cancellation, and is spontaneously broken down by a vacuum expectation value of an isospin singlet scalar field ($\varphi$). In this scenario, $h$ and the Z boson can decay into a pair of RHNs via the $h$-$\varphi$ mixing and the $Z$-$Z^{\prime }$ mixing with $Z^{\prime }$ being a new massive gauge boson, respectively. Estimating the LNV signal and corresponding backgrounds for the ${\ell }^{\pm }{\ell }^{\pm }4j$ final states, we find bounds on the $h$-$\varphi$ mixing and the $Z$-$Z^{\prime }$ mixing as a function of a mass of RHNs at Higgs factories, e.g., at High-Luminosity LHC with $\sqrt{s}=$ 14 TeV, future $e^{-}{e}^{+}$ colliders at $\sqrt{s}=$ 250 GeV, muon colliders at $\sqrt{s}=$ 125 GeV as well as at Z factories, e.g., CEPC and FCC-ee at $\sqrt{s}=$ 91.2 GeV. We also discuss limits on the scalar mixing at $e^{-}{\mu }^{+}$ and ${\mu }^{+}{\mu }^{+}$ collisions ($\mu$TRISTAN) with $\sqrt{s}=$346 GeV/775 GeV and 2 TeV, respectively.

   hep-phPRD(2026)·3 citations
5. 05*

   Probing the Electroweak Phase Transition in the Dark Sector

   Maimoona Razzaq🇮🇹 · Nico Benincasa🇨🇳 · Luigi Delle Rose🇮🇹 · Luca Panizzi🇮🇹

   We study an extension of the Standard Model with a dark SU(2) gauge group, where a dark scalar doublet interacts with the Standard Model Higgs through a portal coupling, inducing mixing after symmetry breaking. A custodial symmetry ensures the stability of the dark gauge bosons, making them viable dark matter candidates. Scanning the parameter space of the model under collider and astrophysical constraints, we find regions that yield the observed relic density and strong first-order phase transitions. The resulting gravitational-wave signals fall within the reach of upcoming space-based detectors.

   hep-ph0 citations
6. 06*

   Real-time evolution of critical modes in the QCD phase diagram

   Yang-yang Tan🇨🇳 · Shi Yin🇩🇪 · Yong-rui Chen🇩🇪 · Chuang Huang🇩🇪 · Wei-jie Fu🇨🇳

   A QCD-assisted relaxation dynamic model for the critical mode of the critical end point (CEP) in the QCD phase diagram is developed, which allows us to investigate the critical slowing down effect quantitatively in the QCD phase diagram, especially in the proximity of the CEP, without any phenomenological parameters. The relaxation time from nonequilibrium to equilibrium in the QCD phase diagram is extracted from the Langevin simulations of the QCD-assisted relaxation dynamic model. It is found that in a narrow region along the phase boundary radiated from the CEP, the relaxation time is enhanced significantly. Outside this narrow region, the relaxation time drops drastically, which implies that the dynamic critical region is small in the QCD phase diagram. We also find that the effects of critical slowing down are mild on the chemical freeze-out curves.

   hep-phnucl-thPRD(2026)·9 citations
7. 07*

   Gravitational Decays of Secluded Scalars and Graviton Dark Radiation

   Kazunori Nakayama🇯🇵 · Fuminobu Takahashi🇯🇵 · Juntaro Wada🇯🇵

   We discuss graviton dark radiation produced by the decay of a secluded scalar field that couples to the Standard Model (SM) only through gravity. Such scalar fields are long-lived, and their decay channels generically include gravitons. If such particles existed and dominated the early universe, a sizable branching ratio into gravitons would yield non-negligible dark radiation that significantly alters the subsequent thermal history of the universe. In this work, we focus on the dark glueball as a representative secluded hidden scalar and compare the decay rates into SM particles via a non-minimal coupling to gravity with those into gravitons, paying attention to how the breaking of conformal invariance affects the amount of graviton dark radiation. We find that decays into the SM are dominated by two-body decay channels into Higgs bosons and gluons. In particular, when the Higgs field has a large non-minimal coupling to gravity, the production of graviton dark radiation is naturally suppressed in the metric formalism, and the SM sector is preferentially reheated and energy transfer to other hidden sectors is suppressed. Finally, we present the expected gravitational-wave spectrum resulting from dark glueball domination.

   hep-phastro-ph.COhep-thPRD(2026)·4 citations
8. 08*

   Probing Azimuthal Alignment in Heavy-Ion Collisions: Clusterization Effects

   Aleksei Nikolskii🇷🇺 · Igor Lokhtin🇷🇺 · Alexander Snigirev🇷🇺

   The influence of kinematic constraints and event selection on the emergence of the alignment phenomenon observed in cosmic-ray experiments is studied within the HYDJET++ model. It is demonstrated that the high degree of alignment, previously identified for realistic values of the transverse momentum disbalance of the most energetic particles, is also observed at the level of the most energetic clusters. In high-multiplicity events, the clustering procedure plays a crucial role in resolving individual particle groups on the detection plane, allowing a more accurate characterization of alignment patterns. These results highlight the combined effects of cluster formation and momentum conservation in shaping the observed azimuthal correlations.

   hep-phhep-thPRD(2026)·0 citations
9. 09*

   Hidden-charm and -bottom tetraquark states with $J^{PC}=1^{-+}$ via QCD sum rules

   Bing-Dong Wan🇨🇳 · Yan Zhang🇨🇳 · Jun-Hao Zhang🇨🇳 · Ming-Yang Yuan🇨🇳

   We investigate the $1^{-+}$ hidden-charm and hidden-bottom tetraquark states within the framework of QCD sum rules. The mass spectra are computed by including condensates up to dimension eight in the operator product expansion. Our results indicate the possible existence of four $1^{-+}$ hidden-charm tetraquark states, with predicted masses of $(4.83\pm 0.15)$ GeV, $(4.88\pm 0.18)$ GeV, $(4.72\pm 0.16)$ GeV, and $(4.79\pm 0.12)$ GeV, while their hidden-bottom counterparts are estimated to have masses of $(11.08\pm 0.16)$ GeV, $(11.16\pm 0.14)$ GeV, $(10.99\pm 0.16)$ GeV, and $(11.03\pm 0.15)$ GeV, respectively. We also analyze the possible decay modes of these tetraquark states, which may be accessible in future experiments at BESIII, Belle~II, LHCb, and future STCF. These findings provide valuable guidance for the experimental search for exotic $1^{-+}$ tetraquark states in both the charm and bottom sectors.

   hep-phEPJA(2026)·6 citations
10. 10*

    A strategy for optimal material identification in solar dark photon absorption

    Theresa M. Backes🇸🇪 · Riccardo Catena🇸🇪 · Michael Krämer🇩🇪

    Dark photons with masses in the 1-100 eV range can be produced in the Sun and subsequently absorbed in terrestrial detectors, offering a promising avenue for probing hidden-sector physics beyond the Standard Model. In this work, we develop a theoretically grounded strategy to identify optimal detector materials for solar dark photon absorption. Our strategy builds on a material-independent upper limit on the absorption rate, which we derive from Kramers-Kronig relations applied separately to the longitudinal and transverse dark photon modes. We show how the optimal material properties depend on the dark photon mass relative to the detector's plasma frequency, identifying the conditions under which a detector can saturate the theoretical upper limit. We then assess the performance of commonly used detector materials in light of these criteria and comment on the prospects of metamaterials featuring tunable plasma frequencies. Our results provide a general and model-independent framework to effectively guide the design of next-generation experiments targeting solar dark photons.

    hep-phastro-ph.CO1 citation
11. 11*

    Discrete flavour and CP symmetries in light of JUNO and neutrino global fit

    Gui-Jun Ding🇨🇳 · Cai-Chang Li🇨🇳 · Jun-Nan Lu🇨🇳 · S. T. Petcov🇮🇹

    Working within the reference three-neutrino mixing framework, we confront the lepton mixing predictions derived using non-Abelian discrete flavour and CP symmetries with the first JUNO data on the solar neutrino mixing parameters ${\sin }^2{\theta }_{12}$ and with the results of the latest global neutrino data analysis. We focus on symmetry breaking patterns for which the lepton PMNS mixing matrix depends only on one or two free real parameters. Performing a comprehensive statistical analysis in each of the considered cases, we report the best fit values, the $3\sigma$ C.L. allowed ranges and the ${\chi }^2$-distributions of the lepton mixing observables - the three mixing angles and the three CP-violation phases. We find that the JUNO measurements can disfavour or rule out a number of the mixing patterns associated with specific types of breaking of the discrete flavour and CP symmetries. The synergy of JUNO, DUNE and T2HK data can provide an exhaustive test of the considered approach to lepton mixing based on non-Abelian discrete lepton flavour symmetries combined with the CP symmetry.

    hep-phJHEP(2026)·15 citations
12. 12*

    Production of charged Higgs bosons associated with CP-even Higgs bosons at future multi--TeV muon colliders

    Quang Hoang-Minh Pham (HCMUS)🇻🇳 · Khoa Ngo-Thanh Ho (HCMUS)🇻🇳 · Khiem Hong Phan (Duy Tan Univ.)🇩🇰

    We report the first results for charged Higgs boson production associated with CP-even Higgses at future multi--TeV muon colliders within the scenario of the Type-Y Two-Higgs-Doublet Model (THDM). The valid parameter regions in the Type-Y THDM are first updated, and based on the allowed parameter space, all two-body decay channels of the charged Higgs boson are then computed with the help of {\tt H-COUP}. Both production processes ${\mu }^{-}{\mu }^{+}\to H^{\pm }{H}^{\mp }h,H^{\pm }{H}^{\mp }H\to t\bar{t}b\bar{b}h,t\bar{t}b\bar{b}H$ are scanned over the constrained parameter space of the considered model. The production cross sections can reach $\sim 0.5$ fb in several regions of the parameter space. The results provide an opportunity to probe charged Higgs bosons produced in association with the heavy CP-even Higgses at the high integrated luminosities proposed for future multi--TeV muon colliders. Furthermore, we evaluate the signal significances for ${\mu }^{-}{\mu }^{+}\to H^{\pm }{H}^{\mp }h\to t\bar{t}b\bar{b}h\to t\bar{t}b\bar{b}b\bar{b}$ with respect to the Standard Model backgrounds. We also estimate the significances by including the top quark decay into leptons and bottom quarks and considering $b$-tagging. Thanks to the high integrated luminosities anticipated at future multi--TeV muon colliders,we find that the signal significances can exceed $\sim 3\sigma$ at several benchmark points selected in the viable parameter space of the Type-Y THDM.

    hep-ph1 citation
13. 13*

    Kinetic Mixing and Axial Charges in the Parity-Doublet Model

    Christian Kummer🇨🇾 · Stefan Leupold🇸🇪 · Lorenz von Smekal🇩🇪

    The standard parity doublet model with its mass-mixing mechanism fails to describe the axial charge $g_A$ of the nucleon. While $g_A=1$ in the original Gell-Mann--Levy model, which reproduces the Adler-Bell-Jackiw anomaly of QCD, in the presence of a chirally invariant baryon mass the mass mixing leads to $g_A<1$ whereas phenomenologically it is about 1.28. We propose to remedy this problem by introducing kinetic-mixing terms corresponding to meson-baryon derivative couplings, similar in spirit to the two-mixing-angle scenario of the $\eta$-${\eta }^{\prime }$ mixing. This extended parity doublet model contains five parameters in the effective baryonic Lagrangian. Three of them can be determined by using the empirical results for the axial charge of the nucleon together with the masses of the nucleon and its parity partner, the $N^{\ast }(1535)$ resonance. We discuss various options how to determine the remaining parameters, touching upon the mass of both parity partners if the chiral condensate is put to zero; the mass of the nucleon in the chiral limit; and the values of meson-baryon coupling constants related to the decays of the resonance to pion-nucleon and sigma-nucleon.

    hep-phnucl-thPRD(2026)·3 citations
14. 14*

    Jet Production at NNLO: Exploring a New Scheme

    Luca Buonocore🇨🇭 · Massimiliano Grazzini🇨🇭 · Flavio Guadagni🇨🇭 · Jürg Haag🇨🇭 · Stefan Kallweit🇨🇭 · Luca Rottoli🇮🇹

    We consider dijet production in $e^{+}{e}^{-}$ collisions and in $H\to b\bar{b}$ decays at next-to-next-to-leading order (NNLO) in perturbative QCD. A new non-local subtraction scheme is applied, for the first time, to obtain the fully differential cross section for these benchmark processes. We discuss and explicitly evaluate the perturbative ingredients needed in the computation, and we compare the performance of different slicing variables to obtain the NNLO corrections.

    hep-phJHEP(2026)·4 citations
15. 15*

    Superexotic $K^{\ast +}{D}^{\ast +}{K}^{\ast +}$ bound state

    Wen-Hao Jia🇨🇳 · Pei-Shen Su🇨🇳 · Wei-Hong Liang🇨🇳 · Raquel Molina🇪🇸 · Eulogio Oset🇪🇸

    We study a system made from $K^{\ast +}{D}^{\ast +}{K}^{\ast +}$ with charge $3$, isospin $I=3/2$, spin $J=3$, and a quark content of $c\bar{d}\bar{s}u\bar{s}u$, which make it highly exotic relative to the standard $q\bar{q}$ structure of mesons. The interaction of the three body system is obtained starting from a cluster of $K^{\ast +}{D}^{\ast +}$ in $I=1$ and $J=2$, that in different works has been found bound, and adding to it an extra $K^{\ast +}$ with spin aligned with those of the vectors of the cluster. We find that the $K^{\ast }{K}^{\ast }$ interaction in $I=1$ and $J=2$ is repulsive, but its strength is small compared to that of $K^{\ast +}{D}^{\ast +}$ in $I=1$ and $J=2$, such that we find a three body state bound by about $100\mathrm{MeV}$ with respect to the mass of a $K^{\ast +}$ and the $K^{\ast +}{D}^{\ast +}$ cluster. The width of the state, of about $10\mathrm{MeV}$, is much smaller than the binding, which facilitates its observation. We suggest to find that state by measuring the invariant mass of $KD{K}^{\ast }$, something feasible in present experimental facilities.

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

    New insights into two-loop running in effective field theories

    Mikael Chala🇪🇸 · Javier López Miras🇪🇸

    We show that, by viewing a 4D effective-field theory as the infrared (IR) limit of the compactified version in 5D, we can compute two-loop anomalous dimensions without gauge-breaking counter-terms, IR re-arrangement or geometric methods. The ultraviolet (UV) divergences in 4D are read from the IR ones in the matching from 5D to 4D. We use this approach to cross-check recent results in the literature, as well as to compute novel two-loop anomalous dimensions in the SMEFT to dimension eight and certain critical exponents in the charged fixed point of the Abelian Higgs model at large number of flavors.

    hep-phhep-th7 citations
17. 17*

    Flavour and precision probes of a class of scotogenic models

    A. Darricau🇫🇷 · H. Lee🇫🇷 · J. Orloff🇫🇷 · A. M. Teixeira🇫🇷

    We address the phenomenological impact of a well-motivated class of scotogenic models regarding flavour and electroweak precision observables. For the case of a ``T1-2-A'' variant, we carry out a full computation of the next-to-leading order corrections to leptonic Higgs and $Z$-boson decays. We revisit previously drawn conclusions on operator dominance and constraints on the parameter space in view of the evolution regarding $\Delta a_{\mu }$. Finally, we consider the role of $H\to \mu \mu$ decays (and other flavour conserving Higgs decays), as well as precision observables in probing this class of models at future colliders.

    hep-ph0 citations
18. 18*

    How large can lepton mixing be?

    J. de Blas🇪🇸 · C. Giuliano🇪🇸 · G. Guedes🇩🇪 · R. Sánchez López🇪🇸 · J. Santiago🇪🇸

    We show that, contrary to common expectations, the observed charged leptons can have a substantial mixing with new heavier fermions, at the level of 20$\%$. This can happen, in the language of effective theories, when the effect of mixing with heavier fermions vanishes at tree level in operators of mass-dimension 6 (or it is suppressed by the small charged lepton masses), a cancellation that can be naturally ensured by symmetries. Using a model that realizes this scenario we consider all current direct and indirect constraints and show that experimental constraints on the mixing are so mild that, given the current direct limit on the mass of the heavy fermions, theoretical considerations become the leading current constraints on the mixing. We also estimate the sensitivity to the mixing at future experiments, including the high-luminosity phase of the LHC and, most notably, the FCC-ee, and FCC-hh. We find a pattern in which the reach of direct searches in hadron machines makes theoretical considerations lead the limits while the precision of lepton machines can beat these theoretical considerations. We find that the FCC can finally reach per mille precision in the mixing squared of the charged leptons

    hep-phJHEP(2026)·3 citations
19. 19*

    Enhancing next token prediction based pre-training for jet foundation models

    Joschka Birk🇩🇪 · Anna Hallin🇩🇪 · Gregor Kasieczka🇩🇪 · Nikol Madzharova🇩🇪 · Ian Pang🇺🇸 · David Shih🇺🇸

    Next token prediction is an attractive pre-training task for jet foundation models, in that it is simulation free and enables excellent generative capabilities that can transfer across datasets. Here we study multiple improvements to next token prediction, building on the initial work of OmniJet-$\alpha$. Instead of tokenizing particles and subsequently only using the token-ID as the model input for both the generative and the classification task, we adopt a hybrid setup, which allows us to use continuous feature vectors as model input while only using token-IDs in the next token prediction target. Secondly, we explore a combined pre-training strategy that combines masked particle modeling and generative learning objectives. Taken together, these changes greatly improve the performance in downstream classification tasks without any loss in generative performance.

    hep-phcs.LGhep-exphysics.data-anMach.Learn.Sci.Tech.(2026)·9 citations
20. 20*

    Data-Driven Predictions for Dark Photon and Millicharged Particle Production

    Elizabeth Allison🇨🇦 · Nikita Blinov🇨🇦

    Accurate signal predictions are essential for interpreting and optimizing fixed-target searches for new physics. Even in minimal models such as the dark photon ($A^{\prime }$) or millicharged particles (mCPs), theoretical uncertainties in hadronic production can be substantial. We introduce a data-driven framework that predicts both the rate and kinematic distributions of $A^{\prime }$ and mCP production directly from measured dilepton events, without relying on specific theoretical production models. This method uses the close correspondence between amplitudes for emission of $A^{\prime }$ or mCPs, and for off-shell Standard Model photon production, the latter being experimentally measurable in full differential form. We demonstrate that normalizing flow models can learn these distributions from data and serve as a fast, realistic Monte Carlo generator for dark sector signal simulations.

    hep-phhep-exPRD(2026)·3 citations
21. 21*

    A new connection between WIMP dark matter and the hierarchy problem

    Maximilian Detering🇬🇧 · Thomas Steingasser🇺🇸 · Tevong You🇬🇧

    This work proposes a direct link between the hierarchy problem and Weakly Interacting Massive Particles (WIMPs): we suggest that the small mass of the Higgs boson arises from being dynamically driven to the scale of the WIMP. Such a special electroweak vacuum is singled out by lying close to the critical boundary of a phase transition, as recently explored in a new class of cosmological solutions to the hierarchy problem. They generically predict the Higgs potential to be destabilised just above the weak scale. Intriguingly, the requirement for new physics to achieve this coincides with two independently well-motivated expectations: a split spectrum of light fermions and heavy bosons, as anticipated from naturalness, and the so-called "WIMP miracle". A WIMP with mass around the weak scale not only happens to have the correct thermal relic abundance to be the dark matter (DM), it can also give rise to the necessary critical boundary at the TeV scale through its Yukawa couplings to the Higgs. We use a higgsino-like singlet-doublet model to illustrate our Higgs-DM criticality scenario and show that if this WIMP DM mass is observed to be greater than ~1.2 TeV then it necessarily implies a strong bound on the Higgs mass and an upper bound on the scale of heavy new physics that restores vacuum stability. It can be thoroughly probed in direct detection experiments, astrophysical signals and future collider searches, further motivating a comprehensive exploration of the remaining heavy WIMP parameter space.

    hep-phastro-ph.COhep-thJHEP(2026)·0 citations
22. 22*

    Minimal Flavor Protection for TeV-scale New Physics

    Admir Greljo🇨🇭 · Ajdin Palavrić🇨🇭 · Ben A. Stefanek🇪🇸

    We determine how much TeV-scale new physics can deviate from flavor universality, $U(3{)}^5$, while respecting stringent bounds on flavor-changing neutral currents. The minimal continuous subgroup that must be approximately preserved is identified as $SU(2{)}_q\times U(1{)}_X$. With only a few symmetry-breaking spurions of $\mathcal{O}(10^{-2})$, all observed fermion hierarchies may be reproduced, offering a new perspective on the SM flavor puzzle. Remarkably, this framework provides structural flavor protection for generic TeV-scale new physics within the SMEFT, enlarging the space of collider-accessible scenarios beyond MFV and $U(2{)}^5$ and allowing for richer patterns of flavor violation.

    hep-phhep-exhep-th15 citations
23. 23*

    Resummed Distribution Functions: Making Perturbation Theory Positive and Normalized

    Rikab Gambhir🇺🇸 · Radha Mastandrea🇺🇸

    Fixed-order perturbative calculations for differential cross sections can suffer from non-physical artifacts: they can be non-positive, non-normalizable, and non-finite, none of which occur in experimental measurements. We propose a framework, the Resummed Distribution Function (RDF), that, given a perturbative calculation for an observable to some finite order in ${\alpha }_s$, will ``resum'' the expression in a way that is guaranteed to match the original expression order-by-order and be positive, normalized, and finite. Moreover, our ansatz parameterizes all possible finite, positive, and normalized completions consistent with the original fixed-order expression, which can include N${}^n$LL resummed expressions. The RDF also enables a more direct notion of perturbative uncertainties, as we can directly vary higher-order parameters and treat them as nuisance parameters. We demonstrate the power of the RDF ansatz by matching to thrust to $\mathcal{O}({\alpha }_s^3)$ and extracting ${\alpha }_s$ with perturbative uncertainties by fitting the RDF to ALEPH data.

    hep-phhep-exphysics.data-anJHEP(2026)·2 citations
24. 24*

    Electroweak phase transition in SMEFT: Gravitational wave and collider complementarity

    Sahabub Jahedi🇨🇳 · Indrajit Saha🇮🇳 · Abhik Sarkar🇮🇳

    We study the first-order electroweak phase transition (FO-EWPT) within the Standard Model Effective Field Theory (SMEFT) framework induced by dimension-6 operators. Such phenomena can be probed independently via \textit{di}-Higgs production at the collider experiments as well as via the detection of gravitational waves (GW). There are three (one) dimension-6 SMEFT operators that simultaneously modify the Higgs potential at tree (1-loop) level and contribute to the \textit{di}-Higgs production at the hadron colliders. With \textit{di}-Higgs production being suppressed at current LHC runs, we aim to probe this production at high luminosity (HL) and high energy (HE) runs of the LHC to achieve better sensitivity of dimension-6 SMEFT operators. The correlations among these operators are analyzed in the context of probing FO-EWPT, emphasizing the complementarity between future GW observations and upgraded LHC searches.

    hep-phastro-ph.COJHEP(2026)·8 citations
25. 25*

    Detecting light axions from supernovae in nearby galaxies

    Francesca Lecce (Bari U. and INFN, Bari)🇮🇹 · Alessandro Lella (Bari U. and INFN, Bari)🇮🇹 · Giuseppe Lucente (SLAC)🇺🇸 · Maurizio Giannotti (Zaragoza U.)🇪🇸 · Alessandro Mirizzi (Bari U. and INFN, Bari)🇮🇹

    Axion-like particles (ALPs) coupled to nucleons can be efficiently produced in core-collapse supernovae (SNe) and then, if they couple to photons, convert into gamma rays in cosmic magnetic fields, generating short gamma-ray bursts. Though ALPs from a Galactic SN would induce an intense and easily detectable gamma-ray signal, such events are exceedingly rare. In contrast, a few SNe per year are expected in nearby galaxies within $\mathcal{O}(10)$ Mpc, where strong magnetic fields can enable more efficient ALP-photon conversions than in the Milky Way, offering a promising extragalactic target. This circumstance motivates full-sky gamma-ray monitoring, ideally combined with deci-hertz gravitational-wave detectors to enable time-triggered searches from nearby galaxies. We show that, under realistic conditions, a decade of coverage could reach sensitivities to ALP-photon coupling $g_{a\gamma }\gtrsim 10^{-16}{\mathrm{GeV}}^{-1}$ for ALP masses $m_a\lesssim 10^{-9}$ eV and assuming an ALP-nucleon coupling close to SN 1987A cooling bound. This sensitivity would allow one to probe a large, currently-unexplored region of the parameter space below the longstanding SN 1987A bound.

    hep-ph6 citations
26. 26*

    Diquark size effects in the quark-diquark approximation for baryons

    Clara Tourbez🇧🇪 · Cyrille Chevalier🇧🇪 · Claude Semay🇧🇪

    Baryons can be described within several theoretical frameworks. Among them, the constituent approach is widely used. In this context, we aim to evaluate the accuracy of a particular model of baryons: the quark-diquark approximation. It consists in separating the three-body system into two subsequent two-body ones: a pair of two quarks, the diquark, and a second system consisting of the diquark and the third quark. This approximation is widely used, but its accuracy is rarely evaluated. The goal of this work is to perform this evaluation by comparing the quark-diquark model with a three-body model, both using the same semi-relativistic interaction. The baryon masses and some characteristic distances are computed and analysed within both approaches. Additionally, an original procedure to establish the quark-diquark potential will be presented with the aim to increase the precision of this approximation. It is shown that a diquark must not necessarily be compact to obtain good baryon masses.

    hep-phEPJA(2026)·2 citations
27. 27*

    From scalar clouds around evaporating black holes to boson star

    Daniel Neves🇵🇹 · João G. Rosa🇵🇹

    We study, for the first time, the evolution of a scalar cloud bound to an evaporating black hole. Our simulations of the associated Schrödinger-Poisson system for non-relativistic and spherically symmetric clouds reveal that a scalar cloud may (partially) survive as a self-gravitating boson star if the black hole evaporates adiabatically until its mass becomes less than one half of the cloud's mass. This yields a novel mechanism for boson star formation and shows that, as previously conjectured, bosonic dark matter production by light primordial black holes may result in micro-boson stars with very large occupation numbers, greatly enhancing their potential detectability even for very weakly interacting dark matter particles.

    ↳ gr-qcastro-ph.COhep-phhep-th2 citations
28. 28*

    Trapped fireshell (halo) of photons and pairs around black-hole horizon: source for ultra-high-energy particles

    She-Sheng Xue🇮🇹

    We study the Compton-rocket effect of strong radiation force accelerating electrons in an opaque fireshell (or fire spot) of dense photons and electron-positron pairs, whose temperature is spatially inhomogeneous and exceeds the electron mass. We find the possibility of the charged-particle acceleration and the avalanche runaway process, leading to a non-trivial probability of ultra-high-energy (UHE) electrons and protons, which subsequently produce very-high-energy (VHE) photons and neutrinos. In a simplified one-dimensional model, we qualitatively show such peculiar dynamics using the fireball, Gamma-Ray Burst central engine, whose inner part inflows and forms a gravitationally trapped fireshell (halo) around the horizon of a black hole. The fireshell is metastable, cooling via UHE particle emissions and blackbody radiation. We calculate the UHE particle luminosity varying in time, and discuss the peculiar features of such produced UHE particles, which lead to VHE particles, in connection with possible numerical simulations, observations and experiments.

    ↳ astro-ph.HEgr-qchep-phJHEAp(2026)·0 citations
29. 29*

    Freeze-out and spectral running of primordial gravitational waves in viscous cosmology

    Giuseppe Fanizza🇵🇹 · Eliseo Pavone🇮🇹 · Luigi Tedesco🇮🇹

    We investigate the impact of shear viscosity on the propagation of primordial gravitational waves (pGW) after inflation. Without assuming a specific inflationary scenario we focus on the evolution of pGWs after they re-enter the horizon during a cosmological epoch characterized by the presence of shear viscosity. We show that shear viscosity introduces an additional damping term in the tensor equation, modifying both the transfer function and the energy density power spectrum. For a constant shear viscosity-to-Hubble ratio the transfer function acquires an extra red tilt, while a time-dependent viscosity leads to a running spectral index ${\Omega }_{\text{GW}}\sim k^{n_{\text{eff}}(k)}$ controlled by the time evolution of the mean free path of the viscous fluid. Our analysis provides a general framework to analytically quantify how shear viscosity can alter the primordial gravitational wave background in standard and non-standard post-inflationary scenarios. As a case study we evaluate the effect of viscosity of the electron-photon-baryon plasma, on both the transfer function and the normalized energy density, finding a $k$-dependent blue tilt due to gravitational wave freeze-out from the viscous phase. This effect corresponds to a fractional difference of order $10^{-3}$.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·2 citations
30. 30*

    Multimessenger Constraints on Supermassive Dark Stars and Their Black Hole Remnants

    Marco Manno🇮🇹 · Thomas Schwemberger🇯🇵 · Volodymyr Takhistov🇯🇵

    Dark matter (DM) annihilation can power the first generation of stars as long lived dark stars (DSs) that grow to supermassive scales $M_{\mathrm{DS}}\gtrsim 10^5{M}_{\odot }$ and eventually collapse into heavy black holes that could seed the supermassive black holes observed at high redshifts. We compute the diffuse electromagnetic emission from a cosmological population of such supermassive DSs and their black hole remnants, tracking the entire DS history and including thermal surface radiation, DM annihilation in adiabatically contracted halos as well as late-time emission from DM overdensity spikes around the resulting black holes. After accounting for photon attenuation, we find that DS related contributions can exceed the Fermi-LAT extragalactic $\gamma$-ray background for thermal relic annihilation cross-sections and DM masses below $\sim 1$ TeV. Our results constitute the first population integrated diffuse multimessenger constraints on supermassive DSs as progenitors of early black holes and demonstrate that diffuse photon and neutrino backgrounds offer a powerful and complementary avenue for probing the role of DM in the formation of the earliest massive structures.

    ↳ astro-ph.COastro-ph.HEhep-ph0 citations
31. 31*

    On the angular momentum and free energy of rotating gluon plasma

    V. Braguta🇷🇺 · M. Chernodub🇫🇷 · E. Eremeev🇷🇺 · I. Kudrov🇷🇺 · A. Roenko🇷🇺 · D. Sychev🇷🇺

    We study the free energy and the angular momentum of rotating hot gluon matter using first-principle numerical simulations of the $\text{SU}(3)$ lattice Yang-Mills theory. We calculate the specific moment of inertia and the specific deformation of the gluon matter as, respectively, the leading and next-to-leading terms in a series in angular velocity over a broad range of temperatures and various spatial boundary conditions. We show that the specific deformation, similarly to the moment of inertia, takes negative values in a phenomenologically interesting region of temperatures above the phase transition and turns positive at higher temperatures.

    ↳ hep-lathep-phhep-thPhys.Part.Nucl.(2026)·5 citations
32. 32*

    The DREAMS Project: Disentangling the Impact of Halo-to-Halo Variance and Baryonic Feedback on Milky Way Dark Matter Speed Distributions

    Ethan Lilie🇺🇸 · Jonah C. Rose🇺🇸 · Mariangela Lisanti🇺🇸 · Alex M. Garcia🇺🇸 · Paul Torrey🇺🇸 · Kassidy E. Kollmann🇺🇸 · Jiaxuan Li🇺🇸 · Olivia Mostow🇸🇪 · Bonny Y. Wang🇺🇸 · Stephanie O'Neil🇺🇸 · Xuejian Shen🇺🇸 · Alyson M. Brooks🇺🇸 and 5 other authors

    Direct detection experiments require information about the local dark matter speed distribution to produce constraints on dark matter candidates, or infer their properties in the event of a discovery. In this paper, we analyze how the uncertainty in the dark matter speed distribution near the Sun is affected by baryonic feedback, halo-to-halo variance, and halo mass. To do so, we harness the statistical power of the new DREAMS Cold Dark Matter simulation suite, which is comprised of 1024 zoom-in Milky Way-mass halos with varied initial conditions as well as cosmological and astrophysical parameters. Applying a normalizing flows emulator to these simulations, we find that the uncertainty in the local DM speed distribution is dominated by halo-to-halo variance and, to a lesser extent, uncertainty in host halo mass. Uncertainties in supernova and black hole feedback (from the IllustrisTNG model in this case) are negligible in comparison. Using the DREAMS suite, we present a state-of-the-art prediction for the DM speed distribution in the Milky Way. Although the Standard Halo Model is contained within the uncertainty of this prediction, individual galaxies may have distributions that differ from it. Lastly, we apply our DREAMS results to the XENON1T experiment and demonstrate that the astrophysical uncertainties are comparable to the experimental ones, solidifying previous results in the literature obtained with a smaller sample of simulated Milky Way-mass halos.

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

    Inflation with a Growing Fifth Dimension

    Rashmish K. Mishra🇺🇸 · Michael Nee🇺🇸 · Lisa Randall🇺🇸

    Inflation generally assumes a field with nonzero potential that leads to inflationary expansion happening at arbitrarily early times. We demonstrate potentially observable consequences of inflation with a finite initial time in a model in five-dimensional warped anti-de Sitter space, with both a UV and an IR brane present during inflation. Considering an inflaton with an approximately flat potential localized on the UV brane, we derive the resulting brane motion in the bulk and the 4D effective action describing the dynamics. A concrete model allows us to evaluate possible consequences of a starting point of inflation. The background evolution is driven by the fast roll of the radion at early times and the slow roll of the inflaton at late times. We find that the action has the form of a two-field hyperbolic inflation model, the two fields being the radion and the inflaton, both of which have a time-dependent background solution. This setup is holographically dual to an inflaton coupled to a strongly coupled confining sector in which the ratio of the confinement scale to the 4D Planck scale evolves cosmologically. Focusing on the period when the equation of state becomes that of inflation, we find that the presence of the IR brane leads to deviations from the approximate de Sitter background in addition to those from the slow-roll parameters of the inflaton potential. We quantify the effect of the presence of the IR brane on the two point function of the adiabatic scalar perturbations and tensor perturbations. The dominant deviations occur at large scales: the adiabatic power spectrum has a blue tilt, while the tensor power spectrum shows oscillatory features. We present numerical fits to the shape of the adiabatic power spectrum, and discuss the implications for cosmic microwave background (CMB) analysis.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2026)·8 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.