Fri·Oct 3, 2025Friday·October 3, 2025

1. 01*

   Semileptonic and nonleptonic weak decays of bottom baryons ${\Omega }_b^{(\ast )}$

   L. Khajouei🇮🇷 · K. Azizi🇮🇷

   We present an investigation into the semileptonic and nonleptonic weak decays of bottom baryons ${\Omega }_b^{\ast }$ and ${\Omega }_b$ within the framework of three-point QCD sum rules. In the semileptonic sector, the ${\Omega }_b^{\ast }\to {\Omega }_c\ell {\bar{\nu }}_{\ell }$ and ${\Omega }_b\to {\Omega }_c^{\ast }\ell {\bar{\nu }}_{\ell }$ transitions are specifically considered. Utilizing the operator product expansion up to dimension six, the responsible form factors of these decays are obtained. The acquired form factors enable us to determine the decay widths in three leptonic channels. Branching ratios related to the ${\Omega }_b$ baryon semileptonic decays are also presented. These invariant form factors are subsequently employed as inputs to determine the nonleptonic weak decay widths in various modes with emitting a pseudoscalar or vector meson. An extensive investigation into all possible decay channels of bottom baryons provides valuable information for future experiments to examine the SM predictions, explores the new physics effects in heavy baryonic decays, and advances the understanding of the internal structure of heavy baryons.

   hep-phhep-exhep-latNPB(2026)·2 citations
2. 02*

   Hadron resonance gas is not a good model for hadronic matter in a strong magnetic field

   Pasi Huovinen🇵🇱 · Michał Marczenko🇵🇱 · Michał Szymański🇵🇱 · Bithika Karmakar🇵🇱 · Pok Man Lo🇵🇱 · Chihiro Sasaki🇵🇱 · Krzysztof Redlich🇵🇱

   We study the effect of magnetic field on particle yields and charge fluctuations in hadron resonance gas. We argue that the big changes in the proton yield and baryon number susceptibility are due to ill-defined description of higher-spin states, and that because of detailed balance, neutral resonances must be affected by the field too.

   hep-phnucl-thEPJ Web Conf.(2026)·2 citations
3. 03*

   Singly heavy tetraquark resonant states with multiple strange quarks

   Xin-He Zheng🇨🇳 · Yao Ma🇨🇳 · Shi-Lin Zhu🇨🇳

   We systematically investigate the S-wave singly heavy tetraquark systems containing two or three strange quarks, $Qs\bar{s}\bar{s}$, $Qn\bar{s}\bar{s}$ and $Qs\bar{s}\bar{n}\left(Q=c,b,n=u,d\right)$, within the constituent quark potential model. We solve the four-body Schrödinger equation using the Gaussian expansion method (GEM) and identify resonances via the complex scaling method (CSM). There are no bound states below the lowest two-meson thresholds. We obtain several compact resonances with $J^P=0^{+},2^{+}$ in $Qs\bar{s}\bar{s}$, and $J^P=2^{+}$ in $Qn\bar{s}\bar{s}$ and $Qs\bar{s}\bar{n}$. The pole positions are mainly distributed around $7.0-7.2$ GeV (bottom) and $3.7-3.9$ GeV (charm), with widths from a few to several tens of MeV. These resonances decay into $D_s{\eta }^{\prime },D_{(s)}^{\ast }\varphi ,{D_s}^{\ast }{K}^{\ast }$ and $D_s^{\ast }{\bar{K}}^{\ast }$ (and their bottom counterparts), providing targets for future experimental searches.

   hep-phhep-exhep-latnucl-thPRD(2026)·6 citations
4. 04*

   A Paradigm for the Coupled-Channel Origin of Resonances: the Exotic $T_{c\bar{s}}$ in $D_{s1}(2460/2536)\to D_s\pi \pi$

   Zhi Yang🇨🇳 · Guang-Juan Wang🇯🇵 · Jia-Jun Wu🇨🇳 · Makoto Oka🇯🇵

   The $T_{c\bar{s}}$ state observed in the decay $D_{s1}(2460{)}^{+}\to D_s^{+}{\pi }^{+}{\pi }^{-}$ provides direct evidence for an isovector open-charm tetraquark state with strangeness--a discovery that demands a systematic framework connecting its origin to the nature of the parent $D_{s1}$. We successfully achieve this connection by two mechanisms, triangle loops and the coupled channel of $DK$-$D_s\pi$ with pure off-diagonal potentials. We first point out the behavior of propagator of $D_s\pi$ will influence the effective potential of $DK\to DK$, then we can successfully obtain the pole of $T_{c\bar{s}}$ on the second Reimann Sheet. By combing with the $\pi \pi$-$KK$ rescattering, not only the two-peak structure in $D_{s1}(2460)$ decay is well reproduced, but also a single-peak structure is predicted in $D_{s1}(2536)$ decay. The marked difference, testable at LHCb and Belle II, is driven by the $S$-wave versus $D$-wave nature of their $D^{\ast }K$ couplings, revealing the underlying structural distinction between the two $D_{s1}$ states. By directly linking hadronic structure to decay patterns, this work provides a template for deciphering the nature of such exotic states. More broadly, by revealing how non-perturbative coupled-channel effects manifest in exotic hadrons, our analysis connects to a universal mechanism shared by systems ranging from halo nuclei to atomic Feshbach resonances, offering a unified perspective across these fields.

   hep-phhep-ex3 citations
5. 05*

   Enhancing the Sensitivity for Triple Higgs Boson Searches with Deep Learning Techniques

   Cheng-Wei Chiang🇹🇼 · Feng-Yang Hsieh🇹🇼 · Shih-Chieh Hsu🇺🇸 · Ian Low🇺🇸 · Zhi-Zhong Li🇺🇸

   Using two benchmark models containing extended scalar sectors beyond the Standard Model, we study deep learning techniques to enhance the sensitivity of resonant triple Higgs boson searches in the fully hadronic $6b$ channel, which suffers from the combinatorial challenge of reconstructing the Higgs bosons correctly from the multiple $b$-jets. More specifically, we employ the framework of Symmetry Preserving Attention Network (\textsc{Spa-Net}), which takes into account the permutational symmetry when a correct pairing of $b$-jets is achieved, to tackle both jet pairing and event classification. Significantly improved efficiency is achieved in signal and background discrimination. When comparing with the conventional Dense Neural Networks, \textsc{Spa-Net} results in up to 40\% more stringent limits on resonant production cross-sections. These results highlight the potential of using advanced machine learning techniques to significantly improve the sensitivity of triple Higgs boson searches in the fully hadronic channel.

   hep-phhep-exJHEP(2026)·4 citations
6. 06*

   GUT-motivated non-invertible symmetry as a solution to the strong CP problem and the neutrino CP-violating phase

   Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵 · Morimitsu Tanimoto🇯🇵 · Tsutomu T. Yanagida🇯🇵

   The unsuppressed CP violation in QCD is a problem in the standard model. If we have some mechanism to guarantee real determinants of the quark mass matrices, the vanishing physical vacuum angle $\bar{\theta }$ indicates the CP invariance at the fundamental level. Thus, the small $\bar{\theta }$ is technically natural, since we have an enhanced CP symmetry in the limit of the vanishing $\bar{\theta }=0$. In fact, it was proved that the vacuum angle is never renormalized up to the four-loop level once it is fixed at 0 value at some high energy scale. The purpose of this paper is to construct a model which guarantees the real determinants of the quark mass matrices assuming a non-invertible symmetry.

   hep-phhep-thPRD(2026)·22 citations
7. 07*

   Addressing the sign-problem in Euclidean path integrals with radial basis function neural networks

   Gabor Balassa🇰🇷

   Solving interacting field theories at finite densities remains a numerically and conceptually challenging task, even with modern computational capabilities. In this paper, we propose a novel approach based on an expansion of the Euclidean path integrals using radial basis function neural networks, which allows the calculation of observables at finite densities and overcomes the sign problem in a numerically very efficient manner. The method is applied to an interacting complex scalar field theory at finite chemical potential in 3+1 dimensions, which exhibits both the sign problem and the silver blaze phenomenon, similar to QCD. The critical chemical potential at which phase transition occurs is estimated to be ${\mu }_c=1.17\pm 0.018$, and the silver blaze problem is accurately described below ${\mu }_c$.

   hep-phhep-latPRD(2026)·4 citations
8. 08*

   Two-loop QCD amplitudes for $t\bar{t}\gamma$ production at hadron colliders

   Guoxing Wang🇫🇷 · Li Lin Yang🇨🇳

   The associated production of a photon and a top-antitop quark pair ($t\bar{t}\gamma$) is important for measuring the top-quark charge and probing the top-photon interaction, and it requires improved theoretical predictions. We focus on the calculation of two-loop amplitudes for $t\bar{t}\gamma$ production at hadron colliders. The infrared singularities with full top-quark mass dependence are derived from universal anomalous dimensions combined with one-loop massive amplitudes expanded to higher orders in the dimensional regulator $ϵ$. The finite remainders are approximated in the high-energy boosted limit using the mass-factorization formula. To validate our approach, we compare approximate one-loop amplitudes up to $\mathcal{O}\left({ϵ}^2\right)$, as well as the two-loop infrared poles, against our exact results. The results in this paper serve as an important step toward next-to-next-to-leading order predictions for $t\bar{t}\gamma$ production.

   hep-phJHEP(2026)·4 citations
9. 09*

   Background Suppression in Quantum Sensing of Dark Matter via Collective Entangled-State Projection

   Shion Chen🇯🇵 · Hajime Fukuda🇯🇵 · Yutaro Iiyama🇯🇵 · Yuya Mino🇯🇵 · Takeo Moroi🇯🇵 · Mikio Nakahara🇫🇮 · Tatsumi Nitta🇯🇵 · Thanaporn Sichanugrist🇯🇵

   We show that measuring dark matter signal by projecting quantum sensors in the collective excited state can highly suppress the non-collective noise background, hence improving the sensitivity significantly. We trace the evolution of the sensors' state in the presence of both dark matter effect and sensors' decoherence effects, optimizing the protocol execution time, and show that the suppression of background by a factor equal to the number of sensors is possible. This method does not require the entanglement of sensors during the signal accumulation time, hence circumventing the difficulty of maintaining the lifetime of the entangled state that is present in other enhancement proposals. This protocol is also general regarding the type of qubit sensors.

   hep-phhep-exquant-phPRD(2026)·7 citations
10. 10*

    Particle momentum spectra, correlations, and maximum entropy principle in high-multiplicity collision events

    S.V. Akkelin🇺🇦

    In this paper, we utilize the maximum entropy prescription to determine a quantum state of a small collision system at the kinetic freeze-out. We derive expressions for multiplicity-selected particle momentum spectra and correlation functions by applying a fixed particle number constraint to this state. The results of our analysis can be useful for interpreting the multiplicity dependence of the particle momentum spectra and correlations in high-multiplicity $pp$ collision events at a fixed LHC energy.

    hep-phhep-thnucl-thPRD(2025)·0 citations
11. 11*

    Resonant production of sterile neutrino dark matter with a refined numerical scheme

    Kentaro Kasai🇯🇵 · Masahiro Kawasaki🇯🇵 · Kai Murai🇯🇵

    The existence of a large primordial neutrino asymmetry is an intriguing possibility, both observationally and theoretically. Such an asymmetry can lead to the resonant production of $\mathrm{keV}$-scale sterile neutrinos, which are a fascinating candidate for dark matter. In this paper, we comprehensively revisit the resonant production processes with a refined numerical analysis, adopting a dynamical discretization of momentum modes to take care of the sharpness of the resonance. We find parameter regions consistent with X-ray and Lyman-$\alpha$ constraints for lepton-to-entropy ratio $\gtrsim \mathcal{O}(10^{-3})$ and $m_{{\nu }_s}\gtrsim 20$keV. We also explore the Affleck-Dine mechanism as a possible origin for such asymmetries. While previous studies considered resonant production after lepton number generation, we numerically investigate cases where a fraction of sterile neutrinos is produced during lepton number injection. In this regime, some parameter sets can shorten the free-streaming length and reduce the required mixing angle to match the observed dark matter abundance, thereby mitigating the observational constraints.

    hep-phastro-ph.COJCAP(2026)·5 citations
12. 12*

    Dispersion relations: foundations

    Bastian Kubis🇩🇪

    We give a pedagogical introduction to the founding ideas of dispersion relations in particle physics. Starting from elementary mechanical systems, we show how the physical principle of causality is closely related to the mathematical property of analyticity, and how both are implemented in quantum mechanical scattering theory. We present a personal selection of elementary applications such as the relation between hadronic production amplitudes or form factors to scattering, and the extraction of resonance properties on unphysical Riemann sheets. More advanced topics such as Roy equations for pion--pion scattering and dispersion relations for three-body decays are briefly touched upon.

    hep-phnucl-th5 citations
13. 13*

    Improved prediction of the mass splitting for $P$-wave $\Omega$ baryons

    Niu Su🇨🇳 · Hua-Xing Chen🇨🇳 · Philipp Gubler🇯🇵 · Atsushi Hosaka🇯🇵

    Using the QCD sum rule method, we investigate the mass splitting for the spin-orbit partner states of the $\Omega (2012)$ baryon assuming that it is a $P$-wave excitation with $J^P=3/2^{-}$. This study is an extension of the previous work [1] in which the masses of these states were estimated with uncertainties too large to extract the reliable mass splitting. In the present study, by directly formulating a sum rule for the mass splitting, we obtain an improved prediction, $\delta M=M_{3/2^{-}}-M_{1/2^{-}}=-18.0_{-17.1}^{+33.6}$ MeV. This result provides a more quantitative insight into the spectrum of $P$-wave $\Omega$ baryons and serves as a useful reference for future experiments.

    hep-phPRD(2026)·2 citations
14. 14*

    Light S-wave pentaquarks on the light front

    Fangcheng He🇺🇸 · Edward Shuryak🇺🇸 · Wan Wu🇺🇸 · Ismail Zahed🇺🇸

    We construct an explicit basis set for pentaquark states on a regular 4-simplex, that diagonalizes the Hamiltonian for light pentaquarks with confinement on the light front (LF). The ensuing eigenstates are free of the center of mass motion and satisfy exact Dirichlet boundary conditions. Hyperfine interactions in the form of color-spin or flavor-spin are shown to lift the degeneracy of the 16 pentastates, with a spectrum that compares fairly with some of the empirical nucleon excited states. The quark PDF for the light pentastates is discussed.

    hep-phnucl-thPRD(2026)·3 citations
15. 15*

    Updating GUT-Scale Pole Higgs Inflation After ACT DR6

    C. Pallis🇬🇷

    We consider models of chaotic inflation driven by the real parts of a conjugate pair of Higgs superfields involved in the spontaneous breaking of a grand unification symmetry at a scale assuming its value within MSSM. We combine a superpotential, which is uniquely determined by applying a continuous R symmetry, with two fractional shift-symmetric Kaehler potentials introducing two free parameters (p,N). The inflationary observables provide an excellent match to the recent ACT data for 1.355<=p<=6.7 and 6x10^-5<= N<=0.7. The attainment of inflation allows for subplanckian inflaton values and possibly detectable primordial gravitational waves with (p,N) values of order unity. A solution to the mu problem of MSSM and baryogenesis via non-thermal leptogenesis can be also accommodated by embedding the model into a B-L extension of MSSM.

    hep-phastro-ph.COhep-thPRD(2026)·17 citations
16. 16*

    Fully charm tetraquark production at hadronic collisions with gluon radiation effects

    Yefan Wang🇨🇳 · Ruilin Zhu🇨🇳

    We report the first complete next-to-leading order QCD calculation for processes involving fully charm tetraquark states, revealing that the renormalization constant of the color-singlet four charm quark operator is exactly unity at this order. We have investigated the possible quark configurations of the fully charm tetraquarks and expanded their states in the color symmetry-antisymmetry basis. By applying the transverse momentum dependent factorization formalism, large logarithms induced by soft and collinear gluon radiations are resummed to all orders in the expansion of the strong interaction coupling at the accuracy of next-to-leading logarithm. By combining LHCb data on the total cross section of the exotic hadron $X(6900)$ and CMS measurements of its spin-parity, we extracted its nonperturbative but universal long-distance matrix element. The rapidity and transverse momentum distributions of the $X(6900)$ and its spin-zero partners are also predicted, which await further experimental verification.

    hep-phhep-exhep-lat14 citations
17. 17*

    The Single-Mass Variable Flavor Number Scheme at Three-Loop Order

    J. Ablinger🇦🇹 · A. Behring🇩🇪 · J. Blümlein🇩🇪 · A. De Freitas🇦🇹 · A. von Manteuffel🇩🇪 · C. Schneider🇦🇹 · K. Schönwald🇨🇭

    The matching relations in the unpolarized and polarized variable flavor number scheme at three-loop order are presented in the single-mass case. They describe the process of massive quarks becoming light at large virtualities $Q^2$. In this framework, heavy-quark parton distributions can be defined. Numerical results are presented on the matching relations in the case of the single-mass variable flavor number scheme for the light parton, charm and bottom quark distributions. These relations are process independent. In the polarized case we generally work in the Larin scheme. To two-loop order we present the polarized massive OMEs also in the $\overline{\mathrm{MS}}$ scheme. Fast numerical codes for the single-mass massive operator matrix elements are provided.

    hep-phhep-exJHEP(2026)·12 citations
18. 18*

    Parton distributions in the shockwave formalism

    Shohini Bhattacharya🇺🇸 · Chuan-Qi He🇨🇳 · Zhong-Bo Kang🇺🇸 · Diego Padilla🇺🇸 · Jani Penttala🇺🇸

    In this work, we calculate a broad class of parton distributions - including parton distribution functions (PDFs), transverse-momentum-dependent distributions (TMDs), generalized parton distributions (GPDs), generalized transverse-momentum-dependent distributions (GTMDs), and diffractive parton distributions - directly from their operator-level definition in the shockwave approximation for the target nucleon. This approximation is valid in the high-energy limit of scattering, corresponding to the small-$x$ regime. The shockwave framework allows us to employ the eikonal approximation and express the parton distributions in terms of Wilson-line correlators, naturally formulated within the color-glass condensate effective field theory. We present a comprehensive set of Feynman rules for evaluating parton distributions in this limit, and demonstrate how they can be systematically applied to calculate all phenomenologically relevant leading-twist parton distributions at leading order. This work establishes a unified starting point for future studies that aim to bridge the color-glass condensate approach with the partonic description of the nucleon.

    hep-phnucl-thJHEP(2026)·9 citations
19. 19*

    Astrophysical Consequences of an Electroweak ${\eta }_{\mathrm{w}}$ Pseudo-Scalar

    Hooman Davoudiasl🇺🇸

    Recently, it has been suggested that the spectrum of physical states in the Standard Model may include an ultralight pseudo-scalar, denoted by ${\eta }_{\mathrm{w}}$, in analogy with the ${\eta }^{\prime }$ state arising from the strong interactions. We find that typical expectations for the properties of ${\eta }_{\mathrm{w}}$ get challenged by astrophysical constraints on the couplings of ultralight bosons. Our strongest limit sets a lower bound of $\mathcal{O}(100\mathrm{TeV})$ on the decay constant of the hypothesized pseudo-scalar. We also briefly discuss whether ${\eta }_{\mathrm{w}}$ could be a dark matter candidate, or the origin of dark energy, but conclude that those identifications appear unlikely. Given the important implications of a potentially overlooked ${\eta }_{\mathrm{w}}$ state for a more complete understanding of the electroweak interactions and a fundamental description of Nature, further theoretical and phenomenological investigations of this possibility and its associated physics are warranted.

    hep-phastro-ph.GAPRD(2026)·3 citations
20. 20*

    ArgoLOOM: agentic AI for fundamental physics from quarks to cosmos

    S. D. Bakshi🇺🇸 · P. Barry🇺🇸 · C. Bissolotti🇺🇸 · I. Cloet🇺🇸 · S. Corrodi🇺🇸 · Z. Djurcic🇺🇸 · S. Habib🇺🇸 · K. Heitmann🇺🇸 · T. J. Hobbs🇺🇸 · W. Hopkins🇺🇸 · S. Joosten🇺🇸 · B. Kriesten🇺🇸 and 3 other authors

    Progress in modern physics has been supported by a steadily expanding corpus of numerical analyses and computational frameworks, which in turn form the basis for precision calculations and baseline predictions in experimental programs. These tools play a central role in navigating a complex landscape of theoretical models and current and potential observables to identify and understand fundamental interactions in physics. In addition, efforts to search for new fundamental interactions increasingly have a cross-disciplinary nature, such that understanding and leveraging interoperabilities among computational tools may be a significant enhancement. This work presents a new agentic AI framework, which we call ArgoLOOM, designed to bridge methodologies and computational analyses across cosmology, collider physics, and nuclear science. We describe the system contours, key internal aspects, and outline its potential for unifying scientific discovery pipelines. In the process, we demonstrate the use of ArgoLOOM on two small-scale problems to illustrate its conceptual foundations and potential for extensibility into a steadily growing agentic framework for fundamental physics.

    hep-phastro-ph.COnucl-th18 citations
21. 21*

    Perturbative unitarity for models with singlet and doublet scalars

    Carolina T. Lopes🇵🇹 · André Milagre🇵🇹 · João P. Silva🇵🇹

    We provide a complete description of perturbative unitarity bounds on the gauge-scalar sectors of models with extra $SU(2)$ doublet, neutral singlet, and charged singlet scalars. Such additions are very frequent in models beyond the Standard Model, and, in particular, they are almost universal in models explaining the dark matter problem. We propose a specific classification and minimal set of scattering matrices containing all the relevant information. We also developed a Mathematica implementation of our results, BounDS, and we use it to fully study a number of simple cases, comparing with the literature, when available. The Mathematica notebook BounDS is provided via a public GitHub repository.

    hep-phInt.J.Mod.Phys.A(2026)·2 citations
22. 22*

    A Limit on the Total Lepton Number in the Universe from BBN and the CMB

    Valerie Domcke🇨🇭 · Miguel Escudero🇨🇭 · Mario Fernandez Navarro🇬🇧 · Stefan Sandner🇺🇸

    At temperatures below the QCD phase transition, any substantial lepton number in the Universe can only be present within the neutrino sector. In this work, we systematically explore the impact of a non-vanishing lepton number on Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB). Relying on our recently developed framework based on momentum averaged quantum kinetic equations for the neutrino density matrix, we solve the full BBN reaction network to obtain the abundances of primordial elements. We find that the maximal primordial total lepton number $L$ allowed by BBN and the CMB is $-0.12(-0.10)\le L\le 0.13(0.12)$ for NH (IH), while specific flavor directions can be even more constrained. This bound is complementary to the limits obtained from avoiding baryon overproduction through sphaleron processes at the electroweak phase transition since, although numerically weaker, it applies at lower temperatures and is obtained completely independently. We publicly release the C++ code COFLASY-C on GitHub which solves for the evolution of the neutrino quantum kinetic equations numerically.

    hep-phastro-ph.COJCAP(2026)·12 citations
23. 23*

    Surveying the complex three Higgs doublet model with Machine Learning

    Rafael Boto🇵🇹 · João A. C. Matos🇵🇹 · Jorge C. Romão🇵🇹 · João P. Silva🇵🇹

    The couplings of the 125 GeV Higgs are being measured with higher precision as the Run 3 stage of LHC continues. Models with multiple Higgs doublets allow potential deviations from the SM predictions. For more than two doublets, there are five possible types of models that avoid flavor changing neutral couplings at tree level by the addition of a symmetry. We consider a softly broken Z2xZ2 three-Higgs doublet model with explicit CP violation in the scalar sector, exploring all five possible types of coupling choices and all five mass orderings of the neutral scalar bosons. The phenomenological study is performed using a Machine Learning black box optimization algorithm that efficiently searches for the possibility of large pseudoscalar Yukawa couplings. We identify the model choices that allow a purely pseudoscalar coupling in light of all recent experimental limits, including direct searches for CP-violation, thus motivating increased effort into improving the experimental precision.

    hep-phJHEP(2026)·10 citations
24. 24*

    On Pre-Inflationary non Gaussianities

    M.Meo🇮🇹 · A. Sagnotti🇮🇹

    We explore the three-point amplitude of curvature perturbations in scenarios suggested by high-scale supersymmetry breaking in String Theory, where the inflaton is forced to climb a steep exponential potential. We can do it at the price of some simplifications, and more importantly with some assumptions on the softening effects of String Theory. These suggest a scenario proposed long ago by Gasperini and Veneziano, where the initial singularity is replaced by a bounce, and the resulting analysis rests on a scale $\Delta$ that leaves some signs in the angular power spectrum of the CMB. The amplitude comprises two types of contribution: the first oscillates around the original result of Maldacena and gives no further prospects to detect a non-Gaussian signal, but the second, which is subtly tied to the turning point at the end of the climbing phase, within the window 62<N<66 for the inflationary e-folds could be compatible with Planck constraints and potentially observable. The amplitudes involving the tensor modes contain only the first type of contribution.

    ↳ hep-thgr-qchep-exhep-phJHEP(2025)·3 citations
25. 25*

    Strong-lensing Perturber Signatures in Self-interacting Dark Matter Simulations

    Demao Kong🇺🇸 · Ethan O. Nadler🇺🇸 · Hai-Bo Yu🇺🇸

    Motivated by recent detections of low-mass perturbers in strong gravitational lensing systems, we investigate analogs of these objects in the Concerto suite, a set of cosmological N-body zoom-in simulations of self-interacting dark matter (SIDM) with high-amplitude, velocity-dependent cross sections. We investigate characteristic halo properties relevant to gravitational imaging measurements, focusing on the projected enclosed mass and the central density slope. In SIDM, these quantities evolve continuously through gravothermal processes, spanning core-expansion and core-collapse phases, in sharp contrast to cold dark matter, where they remain nearly static after halo formation. This SIDM evolution further depends on tidal environment and merger history, which can be probed through strong lensing. We also identify simulated SIDM halos whose properties are consistent with the properties of low-mass perturbers inferred from recent observations, and we demonstrate that the core-collapse mechanism offers a compelling explanation for their observed high densities. Our results highlight the potential of strong gravitational lensing as a powerful probe of dark matter self-interactions.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2026)·16 citations
26. 26*

    BAO miscalibration cannot rescue late-time solutions to the Hubble tension

    Davide Pedrotti🇮🇹 · Luis A. Escamilla🇹🇷 · Valerio Marra🇧🇷 · Leandros Perivolaropoulos🇬🇷 · Sunny Vagnozzi🇮🇹

    Baryon Acoustic Oscillation (BAO) measurements play a key role in ruling out post-recombination solutions to the Hubble tension. However, because the data compression leading to these measurements assumes a fiducial $\Lambda$CDM cosmology, their reliability in testing late-time modifications to $\Lambda$CDM has at times been called into question. We play devil's advocate and posit that fiducial cosmology assumptions do indeed affect BAO measurements in such a way that low-redshift acoustic angular scales (proportional to the Hubble constant $H_0$) are biased low, and test whether such a rescaling can rescue post-recombination solutions. The answer is no. Firstly, strong constraints on the shape of the $z\lesssim 2$ expansion history from unanchored Type Ia Supernovae (SNeIa) prevent large deviations from $\Lambda$CDM. In addition, unless ${\Omega }_m$ is significantly lower than $0.3$, the rescaled BAO measurements would be in strong tension with geometrical information from the Cosmic Microwave Background. We demonstrate this explicitly on several dark energy (DE) models ($w$CDM, CPL DE, phenomenologically emergent DE, holographic DE, ${\Lambda }_s$CDM, and the negative cosmological constant model), finding that none can address the Hubble tension once unanchored SNeIa are included. We argue that the ${\Lambda }_s$CDM sign-switching cosmological constant model possesses interesting features which make it the least unpromising one among those tested. Our results demonstrate that possible fiducial cosmology-induced BAO biases cannot be invoked as loopholes to the Hubble tension "no-go theorem", and highlight the extremely important but so far underappreciated role of unanchored SNeIa in ruling out post-recombination solutions.

    ↳ astro-ph.COgr-qchep-phPRD(2026)·64 citations
27. 27*

    Improved Dark Photon Sensitivity from the Dark SRF Experiment

    Saarik Kalia🇺🇸 · Zhen Liu🇺🇸 · Bianca Giaccone🇺🇸 · Oleksandr Melnychuk🇺🇸 · Roman Pilipenko🇺🇸 · Asher Berlin🇺🇸 · Anson Hook🇺🇸 · Sergey Belomestnykh🇺🇸 · Crispin Contreras-Martinez🇺🇸 · Daniil Frolov🇺🇸 · Timergali Khabiboulline🇺🇸 · Yuriy Pischalnikov🇺🇸 and 6 other authors

    We report the refined dark-photon exclusion bound from Dark SRF's pathfinder run. Our new result is driven by improved theoretical modeling of frequency instability in high-quality resonant experiments. Our analysis leads to a constraint that is an order of magnitude stronger than previously reported (corresponding to a signal-to-noise ratio that is four orders of magnitude larger). This result represents the world-leading constraint on non-dark-matter dark photons over a wide range of masses below $6\mu \mathrm{eV}$ and translates to the best laboratory-based limit on the photon mass $m_{\gamma }<2.9\times 10^{-48}\mathrm{g}$.

    ↳ hep-exhep-phPRL(2026)·4 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.