Wed·Dec 17, 2025Wednesday·December 17, 2025

1. 01*

   A Cosmic Higgs Collider

   Bibhushan Shakya🇩🇪

   This paper examines frameworks and phenomenology of ultrarelativistic Higgs vacuum bubble collisions in a first-order phase transition associated with the Standard Model Higgs field in the early Universe. Such collisions act as a cosmic scale Higgs collider, providing access to energy scales far beyond any temperature reached in our cosmic history, potentially up to the Planck scale. This provides a unique opportunity to probe new physics that couples to the Higgs at very high scales, while also enabling novel applications for various cosmological phenomena, opening tremendous opportunities for particle physics and cosmology. As examples, we demonstrate the viability of nonthermal production of ultra-heavy Higgs portal dark matter up to $10^{16}$ GeV (with observable indirect and direct detection signals up to $m_{\text{DM}}=O(10)$ TeV), and leptogenesis from the production of GUT scale right-handed neutrinos.

   hep-phastro-ph.COhep-th7 citations
2. 02*

   Stellar Superradiance and Low-Energy Absorption in Dense Nuclear Media

   Zhaoyu Bai🇮🇱 · Vitor Cardoso🇩🇰 · Yifan Chen🇨🇳 · Yuyan Li🇮🇱 · Jamie I. McDonald🇬🇧 · Hyeonseok Seong🇩🇪

   Ultralight bosons such as axions and dark photons are well-motivated hypothetical particles, whose couplings to ordinary matter can be effectively constrained by stellar cooling. Limits on these interactions can be obtained by demanding that their emission from the stellar interior does not lead to excessive energy loss. An intriguing question is whether the same microphysical couplings can also be probed through neutron star superradiance, in which gravitationally bound bosonic modes grow exponentially by extracting rotational energy from the star. Although both processes originate from boson-matter interactions, they probe very different kinematic regimes. Stellar cooling probes boson emission at thermal wavelengths, while superradiance is governed by modes whose wavelength is comparable to or greater than the size of the star. Previous work has attempted to relate the microphysical neutron-nucleon scattering and inverse-bremsstrahlung absorption rates directly to the macroscopic growth rate of superradiant bound states. In this work, we re-examine this connection and show that a naive extrapolation of the microphysical absorption rate to the superradiant regime would imply superradiant rates comparable to astrophysical timescales characterised by pulsar spindown. These naive rates are especially high for vector fields. However, we demonstrate that this conclusion changes once collective multiple-scattering effects in dense nuclear matter are taken into account. Repeated nucleon collisions modify the effective low-energy absorption experienced by the bosonic bound state, strongly suppressing the rate relevant for superradiance.

   hep-phastro-ph.HEastro-ph.SRgr-qcJCAP(2026)·2 citations
3. 03*

   Symmetry-preserving calculation of pion light-front wave functions

   Zhao-Qian Yao🇩🇪 · Zhen-Ni Xu🇪🇸 · Yu-Yang Xiao🇨🇳 · Craig D. Roberts🇨🇳 · Jose Rodriguez-Quintero🇪🇸

   Poincaré-covariant Bethe-Salpeter wave functions are used to calculate light-front wave functions (LFWFs) of the pion, $\pi$, and an analogue state, ${\pi }_{s\bar{s}}$. The current masses of the degenerate valence constituents in the ${\pi }_{s\bar{s}}$ are around $25$-times larger than those of the pion's valence constituents. Both valence spin-antialigned ($\mathcal{L}=0$) and valence spin-aligned ($\mathcal{L}=1$) components are obtained and combined to produce the complete LFWF for each system. Comparing predictions delivered by two distinct Bethe-Salpeter kernels, the impact of nonperturbative dynamical effects contained in the more sophisticated (bRL) kernel are seen to be significant; and contrasts between $\pi$, ${\pi }_{s\bar{s}}$ results reveal the interplay between emergent hadron mass and mass effects owing to Higgs-boson couplings. Amongst the results, one finds that for $\pi$, ${\pi }_{s\bar{s}}$, the LFWFs can be approximated by a separable form, with that representation being pointwise reliable in the bRL cases. Moreover, the $\mathcal{L}=1$ component is important; so a LFWF obtained after omission of this piece is typically a poor representation of the system. These features are naturally expressed in $\pi$, ${\pi }_{s\bar{s}}$ transverse momentum dependent parton distribution functions (TMDs). In this connection, it is found that a Gaussian \textit{Ansatz} can only provide a rough guide to TMD pointwise behaviour: magnitude deviations between \textit{Ansatz} and prediction exceed a factor of two on $k_{\perp }^2\gtrsim 0.55$GeV${}^2$. One should therefore be cautious in interpreting conclusions drawn from phenomenological analyses based upon Gaussian \textit{Ansätze}.

   hep-phhep-exhep-latnucl-ex+15 citations
4. 04*

   Glueballs Confinement and Cosmological Phase Transitions

   Adamu Issifu🇧🇷 · Julio C. M. Rocha🇧🇷 · Francisco A. Brito🇧🇷 · Tobias Frederico🇧🇷

   We develop a unified framework in which the dynamics of a scalar glueball field, originating from phenomenological nonperturbative QCD confinement, simultaneously governs the deconfinement transition of strongly interacting matter and drives cosmological inflation. Starting from a temperature-dependent effective potential $V_{eff}(\varphi ,T)$, we show that the glueball mass vanishes at a critical temperature $T_{c\varphi }$, signaling a first-order phase transition characterized by supercooling and a transient metastable vacuum. In the high-temperature regime $T>T_{c\varphi }$, the deconfined phase naturally produces an exponential expansion of the scale factor, providing the correct conditions for inflation. By computing the slow-roll parameters and the resulting spectral index $n_s$, tensor-to-scalar ratio $r_s$, and running ${\alpha }_s$, we confront the model with the Planck observations. The predicted values of $n_s$ and $r_s$ fall within the Planck confidence contours for a broad and physically motivated range of the parameter $\gamma$ and for $N\approx 50\text{–}60$ e-folds. A distinctive linear relation, $r_s=4(1-n_s)-72\gamma$, emerges as a testable signature of the model. Normalization to the observed scalar amplitude further constrains the thermal correction parameter ${\sigma }^2$ and the coupling $\gamma$, linking cosmological data directly to QCD-scale dynamics. These results demonstrate that a confinement-inspired potential can naturally reproduce the observed inflationary phenomenology and offer a novel bridge between early-universe cosmology and the nonperturbative sector of QCD.

   hep-phgr-qchep-th0 citations
5. 05*

   Substructure grooming of inclusive and photon-tagged jets in heavy-ion collisions

   Sa Wang🇨🇳 · Shuang Li🇨🇳 · Jin-Wen Kang🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳

   Jet substructure provides a powerful probe of partonic interactions within the quark-gluon plasma (QGP) in heavy-ion collisions. In this paper, we present a systematic theoretical study of the groomed substructures for both inclusive jets and photon-tagged jets ($\gamma +$jets) utilizing the Dynamical and Soft-Drop Grooming algorithms in PbPb collisions by employing the SHELL transport model. Our theoretical calculations exhibit a suppression at high $k_{\mathrm{T},\mathrm{g}}$, the relative transverse momentum between the two subjets in the groomed substructure, consistent with the recent ALICE measurements. We show that the suppression of high $k_{\mathrm{T},\mathrm{g}}$ arises from the combined effects of the reduction of the subleading subjet transverse momentum due to partonic energy loss and the narrowing of the groomed jet radius $R_g$ induced by selection bias. Our findings demonstrate that no enhancement is observed at high $k_{\mathrm{T},\mathrm{g}}$, even in the complete absence of selection bias. Furthermore, we propose that the broadening of $R_g$ in photon-tagged jets, which are less susceptible to selection bias compared to inclusive jets, provides relatively direct evidence of the jet substructure broadening. Our analysis reveals that the $R_g$ broadening becomes more pronounced as the jet radius increases, where the medium-induced gluon radiation plays a dominant role in driving such broadening. In particular, we find that as the jet radius increases, the Soft Drop grooming algorithm exhibits a better resolving power for the contribution of the medium response to the jet substructure broadening.

   hep-phnucl-th0 citations
6. 06*

   Explicit Rephasing Transformation to PDG Parameterization and Simplified Expression of the Dirac CP Phase by Fermion-Specific Invariants

   Masaki J. S. Yang🇯🇵

   In this letter, we present an explicit rephasing transformation that maps an arbitrary mixing matrix $U$ to the PDG standard parameterization $U^0=\mathrm{diag}(e^{-i\arg U_{e1}},e^{i\arg [\frac{U_{e2}{U}_{\tau 3}}{\det U}]},e^{i\arg [\frac{U_{e2}{U}_{\mu 3}}{\det U}]})$ $U\mathrm{diag}(1,e^{-i\arg [\frac{U_{e2}}{U_{e1}}]},e^{-i\arg [\frac{U_{e2}{U}_{\mu 3}{U}_{\tau 3}}{\det U}]})$. By this procedure, which has remained largely conceptual for more than four decades, six independent phases of the mixing matrix are expressed systematically in terms of the arguments. We also apply this framework to the fermion diagonalization matrices $U^{\nu ,e}$ under the approximation $U_{13}^{\nu ,e}=0$. By partially employing the inversion formula, we factorize all CP phases through the explicit rephasing, thereby revealing the entire CP structure of the mixing matrix. The observable Dirac phase depends only on two relative phases between the fermion sectors and is determined by fermion-specific invariants.

   hep-phPTEP(2026)·6 citations
7. 07*

   Global fits and the search for new physics: past, present and future

   Peter Athron🇨🇳 · Csaba Balázs🇦🇺 · Jon Butterworth🇬🇧 · Christopher Chang🇳🇴 · Andrew Fowlie🇨🇳 · Tomás Gonzalo🇩🇪 · Adil Jueid🇰🇷 · Anders Kvellestad🇳🇴 · Michele Lucente🇮🇹 · Farvah Mahmoudi🇫🇷 · Gregory D. Martinez🇺🇸 · Are Raklev🇳🇴 and 6 other authors

   In this work, we review the history and current role of global fits in the search for physics beyond the Standard Model~(BSM), including precision tests of the Standard Model (SM). Although BSM global fits were initially focused on minimal supersymmetric models, we describe how fits have evolved in response to new data from the Large Hadron Collider (LHC) and elsewhere, expanding to encompass a broad spectrum of BSM scenarios including non-minimal supersymmetry, axion-like particles, extended Higgs sectors, dark matter models, and effective field theories such as SMEFT. We discuss how the role of global fits has shifted from forecasting possible signals of new physics at the LHC to understanding the impact of null results from LHC run-I and II and the discovery of the Higgs boson, and how interest has shifted from global fits for parameter estimation to comprehensive model comparison. We close by discussing potential trends and future applications, emphasizing the potential for machine learning and artificial intelligence to enhance the efficiency of sampling algorithms and comparison between theory and experiment, as well as collaboration and software development.

   hep-phSci.Bull.(2026)·3 citations
8. 08*

   A new idea for relating the asymmetric dark matter mass scale to the proton mass

   Peter Cox🇦🇺 · Rafael E. Pérez🇦🇺 · Raymond R. Volkas🇦🇺

   Asymmetric dark matter is a well-motivated approach to explain the apparent coincidence between the relic densities of visible and dark matter, ${\Omega }_D\simeq 5.4{\Omega }_b$. A complete explanation requires two components, a relation between the particle masses of the dark and visible matter, and a second relation between the number densities in each sector. In this work, we propose a new mechanism to address the former. We consider an extended $SU(3{)}_1\times SU(3{)}_2$ colour group in the visible sector, with QCD embedded as the diagonal subgroup. A ${\mathbb{Z}}_2$ exchange symmetry then relates $SU(3{)}_2$ to a dark, confining $SU(3{)}_D$ sector. The dark matter is a composite state of dark fermions transforming in the fundamental representation of $SU(3{)}_D$. The spontaneously broken ${\mathbb{Z}}_2$ symmetry ultimately leads to a relation between the QCD and dark gauge couplings which, for suitable field content, gives rise to confinement scales of the same order of magnitude. The mechanism leads to a rich particle spectrum above the TeV scale which could be probed at future experiments. The model also naturally includes an axion solution to the strong CP problem.

   hep-phPRD(2026)·2 citations
9. 09*

   On the Renormalization Group in EFTs: On-Shell Bases, Ambiguities, and Divergences

   Anders Eller Thomsen🇨🇭

   Recent results for two-loop renormalization group (RG) functions in effective field theories exhibit unphysical divergences when calculated in an on-shell operator basis. We demonstrate that this can be understood to be a result of omitting non-minimal source terms in the renormalized vacuum functional, which are essential to maintaining renormalizability of and describing the RG flow of Green's functions in an on-shell framework. With the inclusion of the missing source terms, any remaining divergences are ambiguous, generating only unphysical RG flow directed along flavor rotations, and the RG functions are RG-finite. We carefully examine the role of flavor rotations in generating ambiguities in both on- and off-shell RG functions and explore the geometry of a physical coupling space.

   hep-phhep-thJHEP(2026)·2 citations
10. 10*

    Cosmological Bounds on Scotogenic Model with Asymmetric Mediator

    Kento Asai🇯🇵 · Seishi Enomoto🇯🇵 · Takuya Hirose🇯🇵 · Masato Yamanaka🇯🇵

    We study cosmological constraints on the asymmetric mediator scenario, a variant of the scotogenic model that addresses the origins of neutrino masses, dark matter (DM), and the baryon asymmetry. An SU(2)${}_L$ doublet scalar $\eta$ mediates between the visible and dark sectors, while a singlet scalar $\sigma$ serves as the DM candidate. We evaluate the DM relic abundance by solving the Boltzmann equations including $\eta$ decay and scattering processes prior to the freeze-out of the $\eta$ asymmetry, and show Big Bang nucleosynthesis constraints from late-time $\eta$ decays. Combining the DM abundance and BBN bounds, we find the favored parameter space of this model, for instance, the mediator masses of $m_{\eta }\lesssim \mathcal{O}(10)$ TeV.

    hep-phastro-ph.CO0 citations
11. 11*

    Conformal moments of the two-loop coefficient functions in DVCS

    V. M. Braun🇩🇪 · P. Gotzler🇩🇪 · A. N. Manashov🇩🇪

    We develop a new technique and calculate conformal (Gegenbauer) moments of the two-loop coefficient functions in Deeply Virtual Compton Scattering (DVCS). These results are necessary for the extraction of the generalized parton distributions from the experimental data to the NNLO accuracy within the Mellin-Barnes approach.

    hep-phPRD(2026)·3 citations
12. 12*

    Analytic results for one-loop integrals in dimensional regularisation

    Claude Duhr🇩🇪 · Paul Mork🇩🇪

    We present a method to obtain analytic results in terms of multiple polylogarithms for one-loop triangle, box and pentagon integrals depending on an arbitrary number of scales and to any desired order in the Laurent expansion in the dimensional regulator $\epsilon$. Our method leverages the fact that for $\epsilon =0$ one-loop integrals compute volumes of simplices in hyperbolic spaces, which can always be evaluated in terms of polylogarithms using an algorithm recently introduced in pure mathematics. The higher orders in $\epsilon$ can then be expressed as a one-fold integral involving the result for $\epsilon =0$. Remarkably, we find that for up to five external legs, all integrals can be evaluated algorithmically in terms of polylogarithms using direct integration techniques, which, in particular, requires us to rationalise all appearing square roots. We also discuss how we can use the connection to hyperbolic geometry to perform the analytic continuation from the Euclidean region to other kinematic regions.

    hep-ph2 citations
13. 13*

    Signatures of local acceleration of quark-gluon plasma in the dilepton production

    Aritra Bandyopadhyay🇷🇴 · Moulindu Kundu🇷🇴 · Victor E. Ambrus🇷🇴 · Maxim N. Chernodub🇫🇷

    Dilepton production is one of the key probes of the Quark-Gluon Plasma (QGP) that encodes the imaginary part of the electromagnetic current-current correlator. We investigate the effect of local acceleration on the dilepton production by treating acceleration as a small perturbation. Using the thermal Dirac propagator in an accelerated frame within the imaginary-time formalism, we compute the photon polarization tensor and extract its imaginary part. Comparison with the zero-acceleration case isolates the distinct contributions of acceleration to dilepton yields.

    hep-phnucl-thJ.Subatomic Part.Cosmol.(2026)·1 citation
14. 14*

    Precise Predictions for ${\mu }^{\pm }{e}^{-}\to {\mu }^{\pm }{e}^{-}$ at the MUonE Experiment

    Alan Price🇵🇱

    The proposed fixed-target experiment, MUonE, at CERN will aim to measure the hadronic contribution to the running of the QED coupling by analysing the scattering of muons on electrons. Here we present state-of-the-art predictions for the process ${\mu }^{\pm }{e}^{-}\to {\mu }^{\pm }{e}^{-}$, where for the first time an all-order resummation of soft and soft-collinear logarithms has been performed. Further, we match this resummation with the complete next-to-leading and the dominant next-to-next-to-leading higher-order corrections. We find that the resummation has a dominant effect in the signal region, while the systematic matching significantly reduces the perturbative uncertainty.

    hep-phhep-exJHEP(2026)·2 citations
15. 15*

    On the coverage of electroweak-inos within the pMSSM with SModelS -- a comparison with the ATLAS pMSSM study

    Leo Constantin🇫🇷 · Sabine Kraml🇫🇷 · Andre Lessa🇧🇷 · Theo Reymermier🇫🇷 · Wolfgang Waltenberger🇦🇹

    The ATLAS collaboration has recently performed a vast scan of the phenomenological Minimal Supersymmetric Standard Model (pMSSM) with a focus on the electroweak-ino sector, and analysed how their Run 2 searches for electroweak production of supersymmetric (SUSY) particles constrain this dataset. All the SLHA files from the scan as well as the constraints from the eight individual searches considered by ATLAS were made publicly available. We use this material to study how well the ATLAS constraints can be reproduced with SModelS v3.0. Moreover, we explore how the picture changes when also including CMS results, and what can be gained by the statistical combination of analyses. Finally, we discuss the part of parameter space with light electroweak-inos that remains valid despite the stringent LHC limits. Our results underscore the need of a broad, multifaceted approach for maximising sensitivity and closing loopholes in the extensive SUSY parameter space.

    hep-phSciPost Phys.(2026)·5 citations
16. 16*

    Gravitational Waves from Confinement in $SU(N)$ Yang-Mills Theory

    Stephan Huber🇬🇧 · Rory Phipps🇬🇧 · Manuel Reichert🇬🇧

    We provide a detailed analysis of the gravitational wave spectrum of $SU(N)$ pure Yang-Mills theory. The confinement phase transition is described with an effective Polyakov loop model, using the latest lattice data as an input. In particular, recent lattice studies clarified the large-$N$ scaling of the surface tension, which we incorporate through a modification of the kinetic term. We demonstrate that the thin-wall approximation agrees with the Polyakov loop model at small $N$ while it breaks down at large $N$. Furthermore, we include reliable estimates of the bubble wall velocity using a recently developed framework based on a large enthalpy jump at the phase transition. Altogether, this allows us to derive the gravitational wave signals for all $SU(N)$ confinement phase transitions and clarifies the behaviour at large $N$. The strongest signal arises for $N=20$, but overall the predicted signals remain rather weak. Our work paves the way for future studies of other gauge groups and systems with fermions.

    hep-phastro-ph.COhep-lathep-thJHEP(2026)·4 citations
17. 17*

    Matching between Collinear Twist-3 and TMD Fragmentation Function Contributions to Polarized Hyperon Production in SIDIS

    Riku Ikarashi🇯🇵 · Yuji Koike🇯🇵 · Shinsuke Yoshida🇨🇳

    We investigate the consistency between the collinear twist-3 factorization and the transverse-momentum-dependent (TMD) factorization for the transversely polarized hyperon production in semi-inclusive deep inelastic scattering, $ep\to e{\Lambda }^{\uparrow }X$. In particular, we focus on the contributions from the twist-3 fragmentation functions (FFs) and the TMD polarizing FF in the region of the hyperon's intermediate transverse momentum $P_T$, ${\Lambda }_{\mathrm{QCD}}\ll P_T\ll Q$, where both frameworks are valid. In this region the polarizing FF can be expressed in terms of the twist-3 FFs including the purely gluonic ones, and the resulting TMD factorization formula for $ep\to e{\Lambda }^{\uparrow }X$ agrees with the small-$P_T$ limit of the corresponding twist-3 cross section. This matching of the two calculations indicates that the two frameworks describe the same effect in QCD and provide complementary frameworks for the process in different kinematic regions.

    hep-phPRD(2026)·1 citation
18. 18*

    Charged Higgs Pairs at the LHC: A NLO Analysis

    Mohamed Ahmed🇨🇭 · Lisa Biermann🇨🇭 · Harald Ita🇨🇭 · Irina Rusetski🇨🇭 · Michael Spira🇨🇭 · Yelyzaveta Yedelkina🇨🇭

    Charged Higgs-boson pair production at hadron colliders yields information about the trilinear couplings involving charged Higgs fields in extensions of the Standard Model (SM). We consider the type-I two-Higgs doublet model (2HDM) extension and obtain next-to-leading order QCD predictions for the charged-Higgs pair production ($H^{+}{H}^{-}$ production). All production modes, i.e. Drell--Yan-like production, gluon fusion and vector-boson fusion are included in the analysis. We determine uncertainties originating from the scale dependence, the parton-density functions and strong coupling ${\alpha }_s$ at the LHC. We observe that the QCD corrections lead to a significant reduction of the relative scale dependences. These improved predictions will allow for a quantitative interpretation of experimental measurements, in case that charged Higgs states will be observed.

    hep-phhep-exSciPost Phys.Comm.Rep.(2026)·2 citations
19. 19*

    $B$-meson decay width up to $1/m_b^3$ corrections within and beyond the Standard Model

    Martin Lang🇩🇪 · Alexander Lenz🇩🇪 · Ali Mohamed🇩🇪 · Maria Laura Piscopo🇳🇱 · Aleksey V. Rusov🇩🇪

    Starting from the most general effective $|\Delta B|=1$ Hamiltonian describing non-leptonic $b$-quark decays $b\to q_1{\bar{q}}_2{q}_3$, we compute analytic expressions for all matching coefficients of the two-quark operator contributions in the heavy quark expansion~(HQE) of a $B$ meson, up to mass-dimension-six. In addition, we calculate the weak-annihilation contributions, which enter the matching of four-quark operators in the HQE at dimension-six and were previously missing. Our results complete the calculation of beyond Standard Model (BSM) effects in non-leptonic, tree-level, $b$-quark decays relevant for $B$ meson lifetimes and lifetime ratios such as $\tau (B_s^0)/\tau (B_d^0)$. Such BSM contributions naturally arise in generic extensions of the Standard Model (SM) that aim to address the observed tensions between experimental measurements and theoretical predictions based on QCD factorisation in several colour-allowed non-leptonic $B$-meson decays. As a by-product of our calculation, we also determine the matching coefficients in the HQE induced by the QCD-penguin operators within the SM, including both the interference between current-current and penguin operators and the contributions quadratic in the penguin operators. Owing to the suppression of the QCD-penguin Wilson coefficients within the SM, these effects are typically regarded as corrections of order ${\alpha }_s$ and ${\alpha }_s^2$ in the strong coupling, respectively. Our results reproduce the known expressions at dimension-three and provide new results for the coefficients of the chromomagnetic operator at dimension-five and of the Darwin operator at dimension-six.

    hep-phhep-exJHEP(2026)·5 citations
20. 20*

    Swampland bound on quintessential inflation in IDM

    S. Saoud🇲🇦 · M. A. Rbah🇲🇦 · R. Sammani🇲🇦 · E. H. Saidi🇲🇦 · R. Ahl Laamara🇲🇦

    We study a quintessential inflation scenario based on the Inert Doublet Model (IDM) coupled to a quintessence field via an exponential potential $V_0{e}^{-\beta \varphi /M_p}$. Using a conformal transformation from the Jordan frame to the Einstein frame, we derive an effective Starobinsky-type potential modulated by an exponential factor that naturally unifies the inflationary epoch with the late-time accelerated expansion of the Universe. We analyze the resulting two-field dynamics, compute the slow-roll parameters, the primordial perturbation spectrum, as well as the inflationary observables $n_s$ and $r$, and then confront the predictions with the latest $Planck$ and $BICEP/Keck$ data. We find amongst others that the quintessence inflaton coupling must remain extremely weak, in the order of $\beta \lesssim 4\times 10^{-3}$, to satisfy current $CMB$ data, whereas swampland dS conjecture favors a step potential with $\beta \sim \mathcal{O}(1)$, signaling a significant tension between quantum gravity consistency and cosmological viability. We conclude by discussing possible extensions and stabilization mechanisms that could help reconcile the inflationary predictions with swampland constraints.

    hep-ph0 citations
21. 21*

    Cherenkov radiation in isotropic chiral matter: unlocking threshold-free emission

    Ricardo Martínez von Dossow🇲🇽 · Eduardo Barredo-Alamilla🇷🇺 · Maxim A. Gorlach🇷🇺 · Luis Fernando Urrutia🇲🇽

    We investigate Cherenkov radiation in isotropic chiral matter using Carroll-Field-Jackiw electrodynamics, with an axion angle linear in time, to describe a charge moving at constant velocity. By solving the modified Maxwell's equations in cylindrical coordinates and in the space-frequency domain, we derive closed expressions for the circularly polarized electromagnetic fields contributing independently to the radiation. The dispersion relations are obtained by imposing causality at a cylindrical surface at infinity, ensuring outgoing waves. Contrary to initial suppositions, each spectral energy distribution is gauge-invariant and positive, describing radiation at a characteristic angle. We characterize the angles and identify frequency ranges that allow for zero, one, or two Cherenkov cones. Notably, one sector of the model enables threshold-free Cherenkov radiation from slowly moving charges. Our results agree with partial findings in the nonrelativistic limit of earlier iterative analysis and clarify the regimes in which Cherenkov radiation arises in isotropic chiral matter.

    hep-phhep-thPRD(2026)·4 citations
22. 22*

    Implications of Flavor Symmetries for Baryon Number Violation

    Arnau Bas i Beneito🇪🇸 · Ajdin Palavrić🇨🇭 · Andrea Sainaghi🇮🇹

    In the Standard Model, baryon number is an accidental symmetry, whose violation would constitute unambiguous evidence of new physics, with proton decay providing its most prominent experimental signature. At the same time, the peculiar structure of flavor can serve as a guiding principle for exploring possible new-physics effects. In this work, we present a systematic classification of dimension-six baryon-number-violating (BNV) SMEFT operators across several flavor-symmetry assumptions and analyze the resulting phenomenology. Interestingly, in certain flavor scenarios the non-trivial interplay with tiny neutrino masses leads to proton-decay constraints compatible with BNV scales in the multi-TeV range. Finally, we complement the EFT analysis by identifying one-particle UV completions of the BNV operators, revealing scenarios in which the leading-order EFT description may not fully account for their underlying dynamics.

    hep-phhep-exPRD(2026)·6 citations
23. 23*

    Symmetric Dicke States as Optimal Probes for Wave-Like Dark Matter

    Ping He🇨🇳 · Jing Shu🇨🇳 · Bin Xu🇨🇳 · Jincheng Xu🇨🇳

    We identify symmetric Dicke states as the optimal quantum probes for distributed sensing of wave-like dark-matter fields. Within an ensemble-averaged quantum-metrological framework that incorporates the field's random phases and finite coherence, they maximize the Fisher information for short-baseline arrays with $N_d$ sensors and realize a robust $N_d^2$ enhancement. They also retain this collective advantage under amplitude-damping noise, whereas GHZ-type probes are highly fragile and rapidly lose their sensitivity once such noise is included. For two sensors at separations comparable to the dark-matter coherence length, the optimal entangled state acquires an additional spatial-correlation phase and outperforms both Dicke and independent probes. Our framework applies broadly to stochastic bosonic fields, including gravitational waves, and can be implemented with superconducting qubits, atomic ensembles, and NV centers.

    hep-phhep-exquant-ph2 citations
24. 24*

    Higgs-Pair Production via Gluon Fusion: Top-Yukawa- and light-quark-induced electroweak Corrections

    Arunima Bhattacharya🇪🇸 · Francisco Campanario🇪🇸 · Sauro Carlotti🇩🇪 · Jamie Chang🇨🇭 · Javier Mazzitelli🇨🇭 · Margarete Mühlleitner🇩🇪 · Jonathan Ronca🇮🇹 · Michael Spira🇨🇭

    Gluon fusion, $gg\to HH$, is the dominant Higgs-pair production process at the Large Hadron Collider (LHC) and provides the first direct access to the trilinear Higgs self-interaction. The process is loop-induced, with the main contribution emerging from top-quark loops within the Standard Model. In the past, the QCD corrections have been calculated and found to increase the cross section significantly. With the anticipated accuracies achievable at the high-luminosity LHC (HL--LHC), the theoretical uncertainties will be of increased relevance to compete with the experimental precision at the level of less than 30\%. In this work, we take the next steps towards the determination of the complete electroweak corrections at next-to-leading order by calculating the full top-Yukawa and light-quark induced corrections. These corrections modify the cross section moderately in the kinematical regimes of interest.

    hep-phhep-exJHEP(2026)·9 citations
25. 25*

    Towards First Detection of the Solar MSW Transition With JUNO

    Obada Nairat🇺🇸 · John F. Beacom🇺🇸 · Kevin J. Kelly🇺🇸 · Shirley Weishi Li🇺🇸

    Matter-induced neutrino flavor mixing (the Mikheyev-Smirnov-Wolfenstein, or MSW, effect) is a central prediction of the neutrino mixing framework, but it has not been conclusively observed. Direct observation of the energy-dependent MSW transition in the solar electron-neutrino survival probability would solve this, but backgrounds have been prohibitive. We show that our new technique for suppressing muon-induced spallation backgrounds will allow JUNO to measure the MSW transition at $>$4$\sigma$ significance in 10 years. This would strongly support upcoming multi-\$1B next-generation experiments and their goals in cementing the neutrino mixing framework.

    hep-phastro-ph.HEhep-exnucl-ex+1PRL(2026)·1 citation
26. 26*

    Opening the Parameter Space of sub-GeV Inelastic Dark Matter through Parity Violation

    Giovani Dalla Valle Garcia🇩🇪 · Juan Herrero-García🇪🇸 · Joel Jones-Pérez🇵🇪 · Javier Silva-Malpartida🇵🇪

    Sub-GeV dark matter (DM) has emerged as a particularly compelling target in light of the persistent null results from conventional DM searches. While s-wave annihilating DM candidates with masses below the GeV are strongly constrained by indirect-detection bounds, inelastic scenarios can naturally evade these limits. In this work, we show that parity violation can play an important role in inelastic DM models featuring long-lived excited states by inducing small diagonal couplings that significantly relax experimental constraints. A precise determination of the excited-state abundance is essential for assessing the phenomenology of such models. To this end, we solve the integrated Boltzmann equation, fully accounting for up- and down-scattering with electrons and positrons as well as dark-sector conversion processes. Using the resulting abundance, we update the viable parameter space in light of the most recent experimental constraints and demonstrate that parity-violating interactions can reopen broad regions of parameter space that would otherwise be excluded. Moreover, the forthcoming LDMX experiment will probe a significant portion of the parameter space. The framework developed in this work can be readily applied to other exothermic sub-GeV DM scenarios.

    hep-phJHEP(2026)·1 citation
27. 27*

    Renormalization of U(1) Gauge Boson Kinetic Mixing

    Felix Forner🇩🇪 · Felix Tellander🇬🇧

    Quantum field theories containing fields with the same quantum numbers allow for mixed kinetic terms in the Lagrangian, leading to off-diagonal elements in the tree-level two-point function. After removing the mixing by a field rotation, the off-diagonal UV divergences cannot be subtracted by a counterterm, still one can show that the theory is renormalizable. We study kinetic mixing of $U(1)$ gauge bosons in an extension of QED with a massive "dark" photon at one-loop order. In general covariant $R_{\xi }$-gauge, the gauge-fixing function naively obstructs the removal of tree-level mixing but we show that these off-diagonal gauge-dependent contributions cancel. We compare two renormalization schemes: one with and one without kinetic mixing, and relate them via a scale-dependent field transformation, showing that the schemes are equivalent.

    hep-phhep-thPRD(2026)·1 citation
28. 28*

    Compact Stars as Portals to Extra-Dimensional Dark Matter

    Raghuveer Garani🇮🇳 · Chris Kouvaris🇬🇷 · Michel H.G. Tytgat🇧🇪 · Jérôme Vandecasteele🇩🇪

    We investigate hydrostatic configurations of asymmetric dark matter (DM) spheres in scenarios where fermionic DM can propagate into extra spatial dimensions, while Standard Model fields remain confined to ordinary three dimensions. As the number of extra dimensions increases, the effective equation of state for non-relativistic matter softens, making even modest DM accumulation inside neutron stars susceptible to gravitational collapse into extra-dimensional black holes. These black holes are longer lived than their $3$ dimensional counterparts and can accrete enough material to consume an entire neutron star, ultimately producing solar-mass black holes. For geometric cross sections, DM with masses above $\mathcal{O}(10\mathrm{TeV})$ may already be excluded for more than two extra dimensions of size $\mathcal{O}(\mathrm{fm})$ -- sharply contrasting with the standard $3$ dimensional case, where comparable limits only appear for masses $\gtrsim 10^5$ TeV at typical halo densities of $0.3GeV/c{\mathrm{m}}^3$.

    hep-phastro-ph.HEhep-exJCAP(2026)·1 citation
29. 29*

    Non-Thermal Production of Sexaquark Dark Matter

    Marianne Moore (MIT)🇺🇸 · Stefano Profumo (UCSC)🇺🇸

    Standard thermal freeze-out scenarios with QCD-scale interaction rates predict a $uuddss$ sexaquark relic abundance many orders of magnitude below the observed dark matter density, representing a key challenge for sexaquark dark matter models. Additionally, if the maximum post-inflationary temperature never exceeds the QCD confinement scale, the usual thermal/chemical-equilibrium production of the sexaquark near $T\sim T_{\mathrm{QCD}}\simeq 150-170$ MeV never occurs. In this work we show that non-thermal mechanisms can naturally overcome this obstacle. Using late-decaying reheatons as a representative case (while noting the broader applicability), we demonstrate that the final abundance is determined by two quantities: the branching fraction into strange-quark-rich matter and the coalescence probability into sexaquarks during the matter-dominated or early radiation-dominated epoch. We provide compact expressions and benchmark calculations for reheating temperatures $T_R\in [10,100]$ MeV and reheaton masses above the QCD confinement scale. Unlike the predictive but unsuccessful thermal scenario, non-thermal production is sensitive to injection microphysics, coalescence efficiency, and residual entropy dilution. We delineate the viable parameter space, evaluate collider and precision constraints on representative reheaton models, and derive indirect detection bounds on residual antisexaquark populations. Our results establish non-thermal production as a viable pathway to sexaquark dark matter and highlight broader implications for non-equilibrium mechanisms in the early universe.

    hep-phastro-ph.COastro-ph.HEPRD(2026)·1 citation
30. 30*

    Beyond $\mathbf{SU}(\mathbf{N})$: $\mathbf{U}(3)\times \mathbf{U}(2)$ as the underlying symmetry of the strong and electroweak interactions

    Antonio Herrero-Brocal🇪🇸 · Javier Perez-Soler🇪🇸 · Avelino Vicente🇪🇸

    The gauge principle is a cornerstone of particle-physics model building. Nevertheless, many constructions leave certain global $U(1)$ redundancies ungauged. In this work, we take the gauge principle to its logical extreme by promoting all $SU(N)$ symmetries to $U(N)$. We focus on a model based on local $U(3)\times U(2)$ invariance. This framework accounts for several otherwise ad hoc features of the Standard Model, including charge quantization and the observed hypercharge assignments, which emerge here as unique predictions. Furthermore, the internal consistency of the model requires the introduction of right-handed neutrinos and implies the presence of an additional $U(1)$ factor that can be identified with $B-L$, thereby naturally yielding non-zero neutrino masses. In light of these findings, we hypothesize that $U(3)\times U(2)$ constitutes the underlying symmetry of the strong and electroweak interactions. More importantly, our approach opens up novel avenues for model building, driven by this extended interpretation of the gauge principle.

    hep-phPRD(2026)·1 citation
31. 31*

    $i$-incidental $N$-naturalness

    Brian Batell🇺🇸 · Akshay Ghalsasi🇺🇸 · Wenjie Huang🇺🇸 · Matthew Low🇺🇸

    $N$-naturalness is a novel solution to the electroweak hierarchy problem which posits $N$ copies of the Standard Model with varying Higgs mass-squared parameters. Reheating proceeds through a "reheaton" particle that deposits most of its energy density into the Standard Model and small but potentially measurable fractions into the other copies. Typically the sector with the lightest negative Higgs mass-squared is identified as the Standard Model. We demonstrate that $N$-naturalness admits a broader class of realizations in which the Standard Model is identified with a heavier sector, rather than being restricted to the lightest. This is made possible by resonant mixing between the reheaton and the Higgs, which generically causes one sector to be preferentially reheated and to acquire the largest share of the energy density, singling it out as the Standard Model. We demonstrate that this scenario is consistent with current cosmological bounds on new relativistic degrees of freedom and overclosure constraints from heavy stable relics, while future cosmic microwave background and high redshift surveys will probe significant portions of the remaining parameter space. Furthermore, we highlight the possibility of a novel stochastic gravitational wave spectrum from the many cosmological first order QCD phase transitions occurring across the other sectors.

    hep-phJHEP(2026)·2 citations
32. 32*

    Generalized relativistic second order magnetohydrodynamics: A correlation function approach using Zubarev's nonequilibrium statistical operator

    Abhishek Tiwari🇮🇳 · Binoy Krishna Patra🇮🇳

    We use total energy-momentum conservation and the Bianchi identity (magnetic-flux conservation) to construct second-order relativistic magnetohydrodynamics in a Zubarev's non-equilibrium statistical operator (NESO) framework. We obtain all dissipative tensors in the medium by focusing on a relativistic magnetized plasma that preserves parity and is symmetric to charge-conjugation. We also provide Kubo formulas for all transport coefficients that arise at second order. Moreover, we extend the NESO formalism to systematically take into account for nonlocal contributions.

    ↳ physics.flu-dynhep-phhep-thnucl-th+1PRD(2026)·1 citation
33. 33*

    Black Holes and Abelian Instantons

    Isabel Garcia Garcia🇺🇸 · Elliot Maderazo🇺🇸

    We argue that the electromagnetic $\theta$-term is a physical parameter of the Standard Model coupled to gravity. Specifically, in the context of 4-dimensional Einstein-Maxwell theory we show that there exist Euclidean field configurations that have finite action, are asymptotically flat, and feature non-zero electromagnetic second Chern number. These ``gravitational Abelian instantons" correspond to a dyonic extension of a Euclidean wormhole. We argue that these configurations should be included in the gravitational path integral, and that doing so generates a non-perturbative contribution to the vacuum energy density that is $\theta$-dependent. We provide a Lorentzian interpretation of these instantons as capturing the effect of quantum fluctuations corresponding to pair production and annihilation of charged black holes. When $\theta$ is the expectation value of a dynamical axion field, the instantons presented here generate a potential for the axion, thereby breaking the axion shift symmetry. This provides yet another example of how quantum gravity violates global symmetries through the existence of black holes.

    ↳ hep-thgr-qchep-ph3 citations
34. 34*

    Quantum Walks and Exact RG in de Sitter Space

    Daniel Green🇺🇸 · Kshitij Gupta🇺🇸

    The local physics of light scalar fields in de Sitter space is well described by classical random walks, as expressed through the framework of Stochastic Inflation. Recent work has clarified how this formalism arises from quantum field theory (QFT) and the renormalization group (RG), allowing for corrections to this formalism to be determined order by order. Yet, this description is incomplete. For example, the quantum dynamics of these fields are expected to become important when determining the tail of the probability distribution for the fluctuations. In this paper, we develop the understanding of fields in de Sitter as a quantum walk in order to bridge the gap between the classical and quantum description. We use the framework of exact RG to calculate the evolution equation for the reduced density matrix of the long wavelength fields. This master equation provides the direct map from light fields to models of quantum walks. We show how to reduce the master equation to Stochastic Inflation, and provide a new understanding of how the higher-order corrections arise. In the process, we demonstrate that divergences and secular growth in de Sitter, for both light and heavy fields, can be absorbed by (dynamical) renormalization.

    ↳ hep-thastro-ph.COgr-qchep-ph8 citations
35. 35*

    The Role of Microstate Degeneracy in Phase Transitions: Gravitational Waves from Bubble Entanglement

    Gia Dvali🇩🇪 · Lucy Komisel🇩🇪

    Vacuum bubbles, formed in first order phase transitions, have important implications for cosmology. In particular, they source gravitational waves. Usually, it is assumed that, once bubbles are materialized, their state, further evolution and mergers are well-described classically. This paper will show that this intuition breaks down for bubbles which possess high microstate degeneracy. This is generic when the phase transition breaks spontaneously a symmetry. First, the degeneracy enhances the transition rate. Furthermore, the internal quantum state of the bubbles profoundly affects the classical dynamics of their mergers. A bubble, no matter how macroscopic, is born in a maximally entangled quantum state. This state can be viewed as a symmetric superposition of many different would-be classical bubbles. The inner entanglement is largely maintained up until their mergers. The resulting true quantum dynamics of the merger is macroscopically different from any type of classical mergers. These differences are imprinted as macroscopic features in the resulting classical gravitational waves. In this way, the inner microstate entanglement of merging bubbles provides a qualitatively new source of gravitational waves. This phenomenon is quantified and compared with the swift memory burden effect in black hole mergers.

    ↳ hep-thastro-ph.COhep-ph1 citation
36. 36*

    Radiative Spin Polarization in High Energy Storage Rings

    S. R. Mane🇺🇸

    The usual theoretical model for synchrotron radiation in circular accelerators (synchrotrons and storage rings) is to treat a single electron moving in a horizontal circle in a uniform vertical magnetic field, but the true situation in real storage rings is more complicated and exhibits much richer physics. The magnetic fields are inhomogeneous, and there is a bunch of many particles and they traverse a distribution of orbits (hence they encounter different magnetic fields). This results in so-called ``depolarizing spin resonances'' (which do not appear in a simple model of a uniform vertical magnetic field). The calculation of the equilibrium electron spin polarization requires a much more careful analysis. For example, a key insight is that, for motion in inhomogeneous magnetic fields, ``spin flip'' is in general \emph{not} a $180^{\circ }$ reversal of the spin orientation. The physics of radiative spin polarization involves a mix of many disciplines, and provides a good example of cross-disciplinary thinking. We shall also briefly note the connection to astrophysics. The astrophysics literature mainly treats electron motion in very strong magnetic fields, stronger than the Schwinger critical field (for example a neutron star). It is a problem of ongoing interest in astrophysics to study the radiation by electrons circulating in such strong magnetic fields. This article aims to provide the reader with a survey of the basic physics principles of radiative spin polarization, omitting low-level mathematical algebra as much as possible. Such details can be found in the literature, and are not relevant here.

    ↳ physics.acc-phhep-ph1 citation
37. 37*

    Scaling solutions for gauge invariant flow equations in dilaton quantum gravity

    Yadikaer Maitiniyazi🇨🇳 · Christof Wetterich🇩🇪 · Masatoshi Yamada🇯🇵

    We discuss the ultraviolet fixed point of asymptotically safe dilaton quantum gravity. It differs from the Reuter fixed point by the dependence of the Planck mass on a scalar field. The gauge invariant functional flow equation in the most general approximation with up to two derivatives strengthens the argument for the existence of this fixed point. The quantum effective action obtained from the scaling solution for dilaton quantum gravity can describe inflation for early cosmology and dynamical dark energy for late cosmology.

    ↳ hep-thgr-qchep-phPRD(2026)·5 citations
38. 38*

    Chiral gravitational waves from domain walls in Nieh-Yan gravity

    Jiro Soda🇯🇵 · Maki Takeuchi🇯🇵

    We study the scattering of gravitational waves by axion domain walls in teleparallel gravity with the Nieh-Yan term. Since a domain wall causes the parity violation, the transmitted gravitational waves also exhibit the parity violation. We calculate the degree of circular polarization of gravitational waves. It turns out that gravitational waves after going through the domain wall could be chiral. Remarkably, the degree of circular polarization does not depend on the tension of the domain wall.

    ↳ gr-qchep-phhep-thPRD(2026)·1 citation
39. 39*

    The Nucleon Axial Form Factor from Elementary Target Data

    A.S. Meyer🇺🇸 · T. Cai🇨🇦 · M. Moore🇺🇸 · S. Akhter🇮🇳 · Z. Ahmad Dar🇺🇸 · M. Sajjad Athar🇮🇳 · M. Betancourt🇺🇸 · H. Budd🇺🇸 · G. Caceres🇧🇷 · D.S. Correia🇧🇷 · G.A. Díaz🇺🇸 · J. Felix🇲🇽 and 31 other authors

    Precise neutrino-nucleon amplitudes are essential ingredients for predicting neutrino event rates in current and upcoming long-baseline neutrino oscillation experiments. A common neutrino interaction with a low reaction threshold and with most of the energy carried by two final state particles is quasielastic scattering, for which the nucleon axial form factor, $F_A(Q^2)$, is a dominant source of uncertainty. Improvements to the nucleon axial form factor rely on neutrino scattering data with elementary targets to reduce or eliminate the need for nuclear modeling systematics. This work examines constraints on the nucleon axial form factor that can be achieved from datasets of neutrino scattering on deuterium targets, Lattice QCD predictions, and from the recent hydrogen target data from the MINERvA Collaboration. Significant tension is found between hydrogen and deuterium target data, suggesting that extractions from deuterium underestimate both the central value and uncertainty of the form factor. Parameterizations for and uncertainties of the nucleon axial form factor using the $z$ expansion are provided.

    ↳ hep-exhep-phPRD(2026)·14 citations
40. 40*

    Any Light Particle Searches with ALPS II: first science results

    Daniel C. Brotherton🇺🇸 · Zachary R. Bush · Sandy Croatto🇩🇪 · Mauricio Diaz-Ortiz Jr. · Jacob Egge🇩🇪 · Aldo Ejlli🇩🇪 · Henry Frädrich🇩🇪 · Joe Gleason🇺🇸 · Hartmut Grote🇬🇧 · Ayman Hallal🇩🇪 · Michael T. Hartman🇩🇪 · Harold Hollis🇺🇸 and 28 other authors

    The light-shining-through-a-wall experiment ALPS II at DESY in Hamburg searched for axions and similar lightweight particles in its first science campaign from February to May 2024. No evidence for the existence of such particles was found. For pseudoscalar bosons like the axion, with masses below about 0.1 meV, we achieved a limit for the di-photon coupling strength of 1.5e-9 1/GeV at a 95% confidence level. This is more than a factor of 20 improvement compared to all previous similar experiments. We also provide limits on photon interactions for scalar, vector and tensor bosons. An achievement of this first science campaign is the demonstration of stable operation and robust calibration of the complex experiment. Currently, the optical system of ALPS II is being upgraded aiming for another two orders of magnitude sensitivity increase.

    ↳ hep-exastro-ph.GAhep-ph19 citations
41. 41*

    Invisible gravitons and large-scale magnetism

    Massimo Giovannini🇨🇭

    The large-scale limits on the relic signals of gravitational radiation complement the bounds coming from the interferometric detectors (in the audio band) and from the pulsar timing arrays (in the nHz range). Within this inclusive perspective the spectral energy density of the gravitons is sharply suppressed in the aHz region even though the high frequency signal can be comparatively much larger both in the kHz and GHz domains. For there are no direct tests on the expansion rate prior to the formation of the light nuclei, a modified postinflationary timeline affects the total number of $e$-folds and additionally suppresses the tensor to scalar ratio by making the relic signals effectively invisible in the aHz range. The expansion rate prior to nucleosynthesis is further bounded by the evolution of the hypercharge field and the large-scale magnetism also constrains the decelerated expansion rate. The magnetogenesis requirements are compatible with a potentially detectable spectral energy density of the relic gravitons between the MHz and the THz while the tensor to scalar ratio remains suppressed in the aHz region. A maximum of the spectral energy density of the gravitons in the audio domain leads instead to a larger magnetic field when the scale of the gravitational collapse of the protogalaxy (of the order of the Mpc) gets comparable with the Hubble radius before equality. Along a converse viewpoint the results obtained here imply that a long decelerated stage expanding faster than radiation does not affect the high frequency range but reduces the effective number of $e$-folds by so enhancing the tensor to scalar ratio, possibly beyond its observational limit.

    ↳ astro-ph.COgr-qchep-phhep-thInt.J.Mod.Phys.A(2026)·0 citations
42. 42*

    Isocurvature-induced features in multi-field Higgs-$R^2$ inflation

    Flavio Pineda🇲🇽 · Luis O. Pimentel🇲🇽

    We study primordial perturbations in Higgs--$R^2$ inflation in the presence of non-minimal kinetic mixing between the Higgs field and the scalaron. By numerically solving the multifield background and linear perturbation equations, we identify distinct dynamical regimes controlled by the Higgs non-minimal coupling ${\xi }_h$. For ${\xi }_h\sim \mathcal{O}(0.1)$, transient turning of the inflationary trajectory leads to a transfer between adiabatic and isocurvature modes, generating localized features in the primordial curvature power spectrum. In contrast, in the weak-coupling regime ${\xi }_h\ll 1$, the curvature spectrum remains nearly featureless while isocurvature perturbations do not fully decay, resulting in a residual isocurvature component at the end of inflation. We compute the associated CMB angular power spectra and discuss the observational implications of these regimes. Our results highlight the role of multifield dynamics in shaping primordial perturbations and provide constraints on viable realizations of Higgs--$R^2$ inflation.

    ↳ astro-ph.COhep-phPRD(2026)·4 citations
43. 43*

    A universal scaling law for gravitational waves induced during inflation

    Martin Teuscher🇫🇷 · Ruth Durrer🇨🇭 · Killian Martineau🇫🇷 · Aurélien Barrau🇫🇷

    We consider the stochastic gravitational wave background induced by arbitrary source fields that are amplified during cosmological inflation. The associated tensor spectral index is shown to be given, under minimal assumptions, by a simple formula easy to apply in most situations of accelerated expansion. For slow-roll inflation, the induced spectrum is nearly scale invariant, with an index deviating from the standard outcome of vacuum generated gravitational waves. Remarkably, we demonstrate that scale invariance remains true regardless of the original spectrum of the source. We show how this generic approach reproduces the literature on specific models of gravitational wave primordial sources, and discuss its limitations. It provides a very practical estimation of the tensor spectral index for future models, to which subleading corrections can then be added.

    ↳ astro-ph.COgr-qchep-phPRD(2026)·3 citations
44. 44*

    Cosmic Strings Gravitational Wave Probe of Leptogenesis: Thermal, Non-thermal, Near-resonant and Flavourful

    Anish Ghoshal🇵🇱 · Angus Spalding🇬🇧 · Graham White🇬🇧

    Breaking a global or local $U(1{)}_{\mathrm{B}-\mathrm{L}}$ symmetry at high scales simultaneously generates Majorana masses for heavy right-handed neutrinos and produces a network of cosmic strings. The evolution and decay of these strings source a stochastic gravitational-wave background that may be probed by current and future gravitational-wave experiments, while the decays of the resulting massive right-handed neutrinos can generate the baryon asymmetry of the Universe via leptogenesis. We derive analytical bounds for successful leptogenesis with a global and a local $U(1{)}_{B-L}$ symmetry, separately finding an absolute lower bound on the lightest right-handed neutrino mass $M_1>1.74\times 10^8\mathrm{GeV}$ for thermal initial conditions and $M_1>\mathcal{O}(10^6)\mathrm{GeV}$ for non-thermal initial conditions. Allowing for near-resonant leptogenesis relaxes these bounds to TeV scale in both cases making it a viable target at collider searches complementing the GW signals. Full flavour effects are included, and crucially, we determine the region where successful leptogenesis can be probed through gravitational-wave observations in upcoming experiments such as LISA and Einstein Telescope. Importantly, we find that flavour effects rescue regions of the parameter space that are ruled out due to current CMB or gravitational wave measurements.

    ↳ astro-ph.COhep-phPRD(2026)·7 citations
45. 45*

    Drell-Yan at the Electron-Ion Collider

    Henry T. Klest🇺🇸

    The photon is arguably the most universally important particle across all fields of physics. Despite its status as a fundamental particle, at high energies the photon can be seen as a hadronic source of partons. The partonic content of the photon is very poorly constrained compared to that of the proton, with photon PDF uncertainties typically one or two orders of magnitude larger than their proton counterparts, despite the fact that its source, the $\gamma \to q\bar{q}$ splitting, is perturbatively calculable. The high luminosity, excellent particle identification, and far-backward electron tagging capabilities of the Electron-Ion Collider make it an ideal environment for studying photon parton distribution functions. Similar to the $p+p$ or $\pi +p$ systems, photoproduction at the EIC can be thought of as two parton distributions colliding. One of the most powerful processes in such collisions is production of lepton pairs, i.e. $h+p\to l^{+}{l}^{-}+X$, known as the Drell--Yan process. This process has the ability to access for the first time the transverse-momentum-dependent parton distributions of the photon. The transversely polarized proton beam of the EIC additionally provides a possible means of accessing the transversity distribution of the proton without relying on fragmentation functions.

    ↳ nucl-exhep-exhep-phnucl-thPRD(2026)·4 citations
46. 46*

    Anomalous Transport In Low Dimension Materials

    Leonardo Lopes🇧🇷

    This dissertation presents a systematic theoretical investigation into realizing a condensed matter analogue of the Chiral Magnetic Effect (CME) in a quasi-planar, 2+1D system. The research establishes a conceptual bridge between the anomalous transport phenomena of high-energy physics and the emergent electronic properties of engineered honeycomb lattices. The central objective is the formulation of a low-energy effective Hamiltonian that incorporates the necessary ingredients for a CME-like effect. This is achieved by moving beyond pristine graphene, whose inherent sublattice symmetry precludes the formation of a mass gap necessary for defining robust pseudo-chiral states. The core of this work is a model based on a honeycomb lattice with explicitly broken sublattice symmetry, which introduces a band gap and endows the quasi-particles system with a well-defined pseudo-chirality based on sublattice polarization. A time-reversal symmetry-breaking parameter is introduced to asymmetrically modify the valley gaps, creating a controllable non-equilibrium imbalance analogous to the chiral chemical potential in relativistic systems. A key finding is the validation of the physical model consistency; through commutator calculations, the total angular momentum - comprising both orbital and an emergent lattice spin component - is shown to be a conserved quantity. This research successfully transforms the abstract possibility of a 2D CME into a concrete, self-consistent theoretical framework, detailing the precise symmetry conditions required for its manifestation.

    ↳ cond-mat.othercond-mat.mes-hallhep-phhep-th+10 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.