Tue·Dec 23, 2025Tuesday·December 23, 2025

1. 01*

   Landscapes at Colliders

   Raffaele Tito D'Agnolo🇫🇷 · Manuel Ettengruber🇫🇷 · Lian-Tao Wang🇺🇸

   Theories with a large number of long-lived metastable vacua are our only concrete explanation for the puzzling value of the Cosmological Constant (CC). The energy scales where these vacua are realized are unknown. In this work, we consider the possibility that a sector of this landscape of vacua is within experimental reach and discuss its signatures at colliders. We find that striking large-multiplicity final states might have gone undetected due to their relatively small total energy. In particular, this could lead to new exotic Higgs decays, which are both intriguing and challenging to search for. In addition to a general phenomenological analysis of these theories, we also discuss an explicit model where the small values of the CC and the Higgs mass are jointly explained by Weinberg's anthropic argument and a low energy landscape.

   hep-phhep-th3 citations
2. 02*

   A Numerical Method for the Efficient Calculation of Scattering Form Factors

   Carlos Blanco🇺🇸 · Benjamin Lillard🇺🇸 · Jack D. Shergold🇬🇧

   Scintillating molecular crystals have emerged as prime candidates for directional dark matter detector targets. This anisotropy makes them exquisitely sensitive due to the daily modulation induced by the directional dark matter wind. However, predicting the interaction rate for arbitrary molecules requires accurate modeling of the many-body ground as well as excited states, a task that has been historically computationally expensive. Here, we present a theory and computational framework for efficiently computing dark matter scattering form factors for molecules. We introduce SCarFFF, a GPU-accelerated code to compute the fully three-dimensional anisotropic molecular form factor for arbitrary molecules. We use a full time-dependent density functional theory framework to compute the lowest-lying singlet excited states, adopting the B3YLP exchange functional and a double-zeta Gaussian basis set. Once the many-body electronic structure is computed, the form factors are computed in a small fraction of the time from the transition density matrix. We show that ScarFFF can compute the first 12 form factors for a molecule of 10 heavy atoms in approximately 5 seconds, opening the door to accurate, high-throughput material screening for optimal directional dark matter detector targets. Our code can perform the calculation in three independent ways, two semi-analytical and one fully numeric, providing optimised methods for every precision goal.

   hep-phcond-mat.mtrl-scihep-ex4 citations
3. 03*

   A formalism for constructing the QCD power spectrum with finite sampling

   Mithila Mangedarage🇺🇸 · Keith Pedersen🇺🇸 · Zack Sullivan🇺🇸

   Recent progress in the study of QCD phenomena with energy correlators motivates novel approaches to explore the information contained in the QCD radiation spectrum. Fox-Wolfram moments are a set of observables that characterize the angular distribution of energy flow in high-energy collisions. Contrary to their conventional application, they are a class of correlated moments that cannot be reduced to one or several characteristic ones. We present a formalism to extract their fully correlated information content, while systematically discarding small-angle sampling noise, on an event-by-event basis. We show that our approach circumvents a common misspecification of the data in terms of $\delta$-distributions, and is essential in keeping the power spectrum infrared and collinear safe. Our formalism introduces a means of accounting for the varying spatial extent of objects that enter the calculation of the power spectrum, with which experimental artifacts such as detector element geometries and measurement uncertainties can readily be incorporated.

   hep-ph0 citations
4. 04*

   Quantum simulation of real-time current correlators and DIS-inspired observables in the Schwinger model

   Kazuki Ikeda🇺🇸 · Zhong-Bo Kang🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Wenyang Qian🇪🇸

   Hadronic tensors encode the nonperturbative structure of hadrons probed in deep inelastic scattering (DIS), yet their direct evaluation requires real-time evolution that presents a challenge for traditional Euclidean lattice approaches. In this work, we present the first quantum simulation of real-time hadronic current-current correlators in a confining gauge theory, from which DIS-inspired structure functions are extracted as a proof-of-principle demonstration in the Schwinger model, i.e (1+1)-dimensional QED. Using two complementary quantum-simulation strategies -- quantum-circuit and tensor-network methods -- we compute the real-time current-current correlator directly on the lattice and validate our results against exact diagonalization where applicable. From this correlator, we compute the hadronic tensor and determine the longitudinal structure function, the sole nonvanishing DIS observable in two space-time dimensions. Our study demonstrates that quantum simulation offers a viable complementary pathway towards the evaluation of real-time observables relevant for hadronic structure. It also provides a foundation for extending the calculations from Schwinger model to other gauge theories.

   hep-phhep-latnucl-thquant-phJHEP(2026)·5 citations
5. 05*

   New Multi-messenger Probe of Dark Matter-Nucleon Interactions from Ultra-high Energy Cosmic Ray Acceleration

   Stephan A. Meighen-Berger🇦🇺 · P. S. Bhupal Dev🇺🇸 · Matheus Hostert🇺🇸

   It has been suggested that the density of dark matter (DM) halo can be highly enhanced around supermassive black holes at the centers of massive galaxies. If real, these DM \emph{spikes} would offer new opportunities to probe the properties of DM. In this work, we point out that DM spikes can significantly impact the composition and survivability of ultra-high-energy cosmic rays accelerated near supermassive black holes. A large DM-nucleon cross section would fragment heavy nuclei into lighter elements and prevent them from attaining the energies observed at Earth. While the origin of cosmic rays remains a mystery, we show that if the highest-energy cosmic rays on Earth come from sources like NGC 1068, then cross sections of size ${\sigma }_{\chi p}\le 10^{-33}\left(\frac{m_{\chi }}{\mathrm{GeV}}\right)\mathrm{c}{\mathrm{m}}^2$ would be excluded by cosmic ray data. These bounds can be competitive with other existing probes and rule out new parameter space in the DM mass region $m_{\chi }\in [3\mathrm{MeV},30\mathrm{MeV}]$. While the uncertainties on the acceleration mechanism of cosmic rays prevent us from setting robust limits, our study highlights an important connection between DM spikes and cosmic ray physics that is complementary to existing cosmological and direct detection constraints.

   hep-phastro-ph.HEPRD(2026)·7 citations
6. 06*

   Cross section and parametrization of charmonium decay

   Xiao-Hu Mo🇨🇳 · Jin-Tao Chen🇨🇳 · You-Kai Wang🇨🇳

   The parametrization forms of charmonium quasi two body decays are discussed in detail in this paper. The symmetry analysis and magnetic transition description are utilized to provide the multi-aspect comprehension of the decay dynamics, including the meson mixing angle, form factor, and $SU(3)$ symmetry breading effect. As the prerequisite, the electromagnetic cross sections involving scalar and pseudoscalar, are calculated for eight final states based on the approach of current algebra. Moreover, the mathematical manipulations of calculation for four kinds of final states are spelled out to illuminate the technique strategy.

   hep-phPLB(2026)·0 citations
7. 07*

   A study of retardation models for phenomenological interactions in hadronic physics

   M. De Sanctis🇨🇴

   A study of retardation models for the hadronic quark interaction is performed starting from a coordinate space calculation that elaborates a classical electrodynamics procedure. The possibility of constructing a corresponding quantum operator is critically analyzed also performing some numerical matrix element calculations. A comparison of the developed model with the Feynman diagram interaction at tree-level is studied, showing a substantial physical correspondence of the two models. Possible applications and generalizations are discussed.

   hep-phActa Phys.Polon.B(2026)·0 citations
8. 08*

   Ultralight dark matter search in a large liquid scintillator detector

   Luis A. Delgadillo🇨🇳 · O. G. Miranda🇲🇽 · Hiroshi Nunokawa🇧🇷

   The nature of dark matter remains one of the most profound mysteries in modern physics. In this work, we investigate the phenomenological implications of ultralight scalar dark matter (ULDM) coupled to neutrinos. We focus on a large homogeneous liquid scintillator detector, analyzing the regime where ULDM oscillations lead to time-averaged distortions in neutrino oscillation probabilities. We derive sensitivity limits on the modulation parameters ${\eta }_{{\Delta }_{21}}$ and ${\eta }_{{\Delta }_{31}}$, which quantify ULDM-induced smearing effect in oscillations driven by solar ($\Delta m_{21}^2$) and atmospheric ($\Delta m_{31}^2$) mass-squared differences. We further demonstrate that ULDM interactions could produce a mild impact on both the determinations of the neutrino oscillation parameters and the neutrino mass ordering sensitivity. These results showcase the benefits of a large liquid scintillator detector as a powerful probe of neutrino-ULDM interactions via neutrino oscillations.

   hep-phhep-exPRD(2026)·3 citations
9. 09*

   High-Energy Pion Scattering in Holographic QCD: A Comparison with Experimental Data

   Adi Armoni🇬🇧 · Dorin Weissman🇮🇹

   Following Polchinski and Strassler [1] and our previous work [2], we study high-energy pion scattering in the holographic QCD hard-wall model. In particular, we focus on comparing our predictions for the angular dependence of ${\pi }^{+}{\pi }^{-}\to {\pi }^{+}{\pi }^{-}$ scattering with experimental data extracted from the process ${\pi }^{-}p\to {\pi }^{+}{\pi }^{-}n$. Having previously shown that our approach reproduces the constituent counting rule found in QCD, we now observe qualitative agreement between our predictions and the extracted data in the high-energy fixed-angle regime. We also provide predictions for all other 2-to-2 pion scattering processes. Our approach can be extended to a broader range of meson and glueball scattering processes in various holographic QCD models.

   hep-phhep-thJHEP(2026)·1 citation
10. 10*

    Lepton anomalous magnetic moments: Theory

    Hartmut Wittig🇩🇪

    The anomalous magnetic moment of a lepton encodes the fraction of the lepton's interaction strength with an external magnetic field, which is generated by quantum corrections. Lepton anomalous magnetic moments are sensitive probes of fundamental interactions and play a pivotal role in the quest for "new physics" that may be able to explain the shortcomings of the Standard Model. This chapter introduces the basic concepts and describes the calculation of the individual contributions arising from electromagnetism, the strong and the weak interactions.

    hep-phhep-lat2 citations
11. 11*

    Complete NLO corrections to off-shell $\mathbf{t}\bar{\mathbf{t}}$ production in the $\mathbf{\ell }+\mathbf{j}$ decay channel

    Leon Mans🇩🇪 · Daniel Stremmer🇩🇪 · Malgorzata Worek🇩🇪

    We present the calculation of the complete NLO corrections to the off-shell top-quark pair production in the $\ell +j$ decay channel, denoted as $pp\to {\ell }^{-}{\bar{\nu }}_l{j}_b{j}_{b}jj+X$, where ${\ell }^{-}=e^{-},{\mu }^{-}$. The calculation consistently preserves the finite-width effects of the top quarks and massive gauge bosons, as well as takes into account all doubly-, singly-, and non-resonant contributions along with their interference effects. All Born-level contributions, at the perturbative orders from $\mathcal{O}({\alpha }_s^4{\alpha }^2)$ to $\mathcal{O}({\alpha }_s^0{\alpha }^6)$, are included and corrected by both NLO QCD and NLO EW effects. Furthermore, all possible partonic initial states are taken into account. Particular attention is paid to the infrared safety in the presence of photons and jets. This requires the use of the so-called parton-to-photon fragmentation function and the photon-to-jet conversion function, which makes the democratic photon-parton clustering and the $\gamma \to q\bar{q}$ splittings finite. We present our findings at the integrated and differential fiducial cross-section levels for the LHC Run III centre-of-mass energy of $\sqrt{s}=13.6$ TeV. In addition, we quantify the impact of subleading NLO effects, in particular, electroweak Sudakov logarithms and non-resonant QCD backgrounds. Two analysis strategies are employed and compared, namely with and without the resonance-enhancing requirement on the invariant mass of the two light jets, $|M_{jj}-m_W|<{\mathcal{Q}}_{\text{cut}}=20$ GeV, illustrating the relationship between QCD background suppression, off-shell effects, interferences, and complete NLO corrections.

    hep-phhep-exJHEP(2026)·1 citation
12. 12*

    Comment on "Spontaneous baryosynthesis with large initial phase"

    James M. Cline🇨🇦

    Recently arXiv:2512.11011 set out to improve on previous work from 1994 by Dolgov and Freese, who used a small-angle approximation to derive the yield of spontaneous baryogenesis from a rolling phase, a pseudo-Nambu-Goldstone boson coupled to the baryon current. The goal of the recent paper was to investigate what happens when the small-angle approximation is not imposed. I point out a serious technical shortcoming in their derivation.

    hep-phNPB(2026)·0 citations
13. 13*

    Universal Non-Equilibrium Cascade in QGP Light-Nuclei Formation and Cosmological Bose-Einstein Condensation

    Takeshi Fukuyama🇯🇵

    Recent ALICE results demonstrate that over 90\% of light nuclei and anti-nuclei ($d$, $\bar{d}$) observed in heavy-ion collisions originate from a non-equilibrium, multi-stage process: $\Delta$-resonance production, decay into correlated nucleons, and their subsequent coalescence in a cooler hadronic environment. Although the final particle yields appear thermal, the underlying dynamics is strongly time-ordered and highly non-equilibrium. We show that this mechanism exhibits a striking universality with the formation of Bose-Einstein condensates (BEC) and associated density spikes in cosmological scalar-field dark-matter scenarios. In both systems -- the quark-gluon plasma near hadronization and the early universe approaching the BEC critical temperature -- the relevant degrees of freedom reorganize through a hierarchical cascade: high-energy modes first convert into intermediate excitations, which then seed low-energy coherent structures once the temperature crosses a threshold. This work highlights an unexpected theoretical bridge between heavy-ion physics and cosmology, suggesting a common class of emergent non-equilibrium phenomena behind structure formation in both extremes.

    hep-phhep-th1 citation
14. 14*

    Two-Component Dark Matter with an SU(2) Dark Sector

    Shao-Long Chen🇨🇳 · Wen-wen Jiang🇨🇳

    We propose an extension to the standard model incorporating a dark sector with a non-Abelian SU(2) gauge symmetry. The model yields stable dark matter candidates, protected by a residual $Z_3$ symmetry arising after the spontaneous symmetry breaking. The dark sector interacts with the SM via a Higgs portal, facilitated from mixing between the SM Higgs doublet and a dark scalar singlet. The model features two distinct DM components. We analyze theoretical and experimental constraints, including perturbativity, unitarity, vacuum stability, dark matter relic density, direct detection, indirect detection, Higgs invisible decays, dark radiation, and ellipticity. Our findings identify viable parameter spaces that satisfy these constraints, as exemplified by two benchmark points.

    hep-phJCAP(2026)·1 citation
15. 15*

    Investigating the internal structure of $X(6900)$ in the $2J/\psi$ decay channel

    Duo-Duo Lu🇨🇳 · Shao-Zhou Jiang🇨🇳

    Assuming $X(6900)$ is a tetraquark state, the decay width of $X(6900)\to 2J/\psi$ is calculated in a covariant quark model, with the diquark-antidiquark $[cc][\bar{c}\bar{c}]$ picture. Two possible structures, vector-vector and axial-vector--axial-vector coupling, are investigated. The result indicates that the axial-vector--axial-vector coupling is consistent with the experiments. Additionally, as another application of the covariant quark model, the decay width of $X(6900)\to 2{\eta }_c$ is predicted to be $66\sim 88$ keV.

    hep-phPRD(2026)·10 citations
16. 16*

    Collapse of Coulomb Bound States of Vector Bosons

    V.V. Flambaum🇦🇺 · H. B. Tran Tan🇺🇸

    Charged spin 1 (vector) particles behave very differently from electrons or scalars in a Coulomb field. For an infinitely heavy point-like nucleus their bound state wave functions fall to the centre, and embedding the system in a renormalisable electroweak-type theory does not remedy this short-distance pathology. We therefore solve the pure Coulomb problem for a finite nuclear radius $R$ and recover the point nucleus limit by letting $R\to 0$. This approach allows us to include the crucial Upsilon term in the wave equations, which for the point-like nucleus is proportional to delta(r) and was ignored in the previous calculations of the energy spectrum. Several unusual effects emerge: (i) The Upsilon term supports a tower of states located mainly inside the nucleus. As R -> 0 their number diverges, most lying in the negative energy continuum (energy epsilon < - m c^2). They trigger vacuum breakdown - particle-antiparticle pair creation that ultimately screens the nuclear charge. (ii) Ordinary Sommerfeld-like states (with binding energy smaller m c^2) persist, but a finite fraction of each wave function leaks into the nucleus, even as R -> 0. (iii) Charge density of a negatively charged vector particle changes sign in a vicinity of the nucleus and becomes positive charge density, whereas the Upsilon term ensures its density inside the nucleus remains negative. (iv) For weak coupling, Z alpha << 1, yet with mR <Z alpha, the non-relativistic solution differs qualitatively from Schrodinger theory despite binding energies are well below m c^2; agreement is recovered only when Z alpha << mR. These phenomena highlight the distinctive and subtle behaviour of spin-1 particles in the Coulomb field.

    hep-phnucl-thphysics.atom-phPRD(2026)·0 citations
17. 17*

    Quark-model search for compact $c\bar{c}uds$ pentaquark states

    Emiko Hiyama🇯🇵 · Atsushi Hosaka🇯🇵 · Makoto Oka🇯🇵 · Georg Wolschin🇩🇪

    A potential quark model is used to search for a $P_{c\bar{c}s}^0=(c\bar{c}uds{)}^0$, $J^P=1/2^{-}$ pentaquark state that has recently been observed experimentally by the LHCb collaboration at 4338.2 MeV, with a width of 7.0 MeV and high statistical significance $>15\sigma$. Our model Hamiltonian reproduces the masses of the low-lying charmed and strange hadrons. We use the Gaussian expansion method {to solve the} five-body Schrödinger equation. Employing the real scaling method {including} the relevant meson-baryon thresholds explicitly, sharp resonances are distinguished from the meson-baryon scattering states. We incorporate new color states of the color-octet meson and baryon configurations as well as the color-singlet configurations for the five-quark states. We find no $J^P=1/2^{-}$ resonance close to the observed state, and also none in the $J^P=3/2^{-}$ state. This increases the likelihood that $P_{c\bar{c}s}^0$ is a ${\Xi }_c\bar{D}$ hadronic molecule rather than a compact state.

    hep-phPRD(2026)·2 citations
18. 18*

    Magnetic monopoles as probes of the global structure of the Standard Model

    Yunji Ha🇬🇧

    The magnetic charges of monopoles arising in ultraviolet completions of the Standard Model are constrained by the global structure of the gauge group. After electroweak symmetry breaking, a subset of the ultraviolet monopoles carrying magnetic charges 3$g_D$ and $6g_D$ can survive as isolated, colour-neutral states in the infrared. We show that this selection rule follows from the interplay between the symmetry structure and the magnetic 1-form symmetry, and discuss how the relic abundance of such monopoles can be naturally suppressed by the symmetry breaking scale. We further demonstrate that such monopoles with Lorentz factor $\gamma \lesssim 10^4$ propagate through matter with ionisation energy loss profiles scaling as $g^2$ using CORSIKA Monte Carlo simulations.

    hep-ph0 citations
19. 19*

    Charm multiplicity distribution in high energy pp collisions with PYTHIA

    Y.N. Lima🇧🇷 · C. Jahnke🇧🇷 · M. Munhoz🇧🇷 · F.S. Navarra🇧🇷

    With the growth of statistics in the future experiments at the LHC, the number of events with charm production will increase substantially. It may become possible to measure the multiplicity distribution of charm particles. Using PYTHIA-8, we generated charm multiplicity distributions in $pp$ collisions for different pseudorapidity ranges ($|\eta |<0.5,1.0,2.0,3.0$) and center-of-mass energies ($\sqrt{s}=$ 0.9, 2.36, 2.76, 7.0, 8.0, 13.0 TeV). We investigated the role played by multiple parton interactions and color reconnection. We compared the multiplicity distribution of D mesons with the charm quark multiplicity distribution. We observe that the "quark-hadron" duality hypothesis is satisfied. With the obtained distributions we tested the validity of the Koba-Nielsen-Olesen scaling. We also parameterized the charm distributions considering the Poisson and negative binomial distributions.

    hep-phPRD(2026)·0 citations
20. 20*

    Emergent chiral spin symmetry, non-perturbative dynamics and thermoparticles in hot QCD

    Owe Philipsen🇩🇪

    Several non-perturbative results for hot QCD are challenging some aspects of the phase diagram and its associated degrees of freedom which were previously believed to be well understood. With increasing temperature, the chiral crossover is followed by an intermediate region with an approximate chiral spin symmetry larger than chiral symmetry, in which pseudo-scalar mesons continue to exist as hadron-like excitations, before at some higher temperature the expected chiral symmetry is recovered. By testing general formal considerations against lattice data, it can be shown that thermally modified versions of stable vacuum particles, so-called thermoparticles, form the constituents of thermal quantum field theories, with properties quite different from what is expected perturbatively. This ``viewpoint'' aims to raise broader and, in particular, phenomenological interest in these directions.

    hep-phhep-latnucl-thEPJA(2026)·1 citation
21. 21*

    Next-to-Next-to-Leading-Order Corrections to the $B\to \pi$ Form Factors from Light-Cone Sum Rules

    Yong-Kang Huang🇨🇳 · Dong-Hao Li🇨🇳 · Cai-Dian Lü🇨🇳 · Bo-Xuan Shi🇨🇳 · Hui-Xin Yu🇨🇳

    By incorporating the available leading-power results at $\mathcal{O}({\alpha }_s)$ and next-to-leading-power corrections at tree level, we improve the precision of the theoretical predictions for $B\to \pi$ form factors to the $\mathcal{O}({\alpha }_s^2{\beta }_0)$ level in the large-recoil region using the light-cone sum rule approach with $B$-meson light-cone distribution amplitudes. We find that the QCD corrections at $\mathcal{O}({\alpha }_s^2{\beta }_0)$ contribute approximately $+6.1\%$ compared to the tree-level result. Combining the light-cone sum rule predictions in the large-recoil region, lattice QCD results in the small-recoil region, we perform a combined fit for the $B\to \pi$ form factors across the full kinematic range. Utilizing these form factors, we calculate the branching ratios, lepton-flavor-universality ratio $R_{\pi }$, forward-backward asymmetry ${\mathcal{A}}_{\mathrm{FB}}$, flat term ${\mathcal{F}}_{\mathrm{H}}$ and polarization asymmetry ${\mathcal{A}}_{{\lambda }_{\mathrm{\ell }}}$ of $B\to \pi \mu {\bar{\nu }}_{\mu }$ and $B\to \pi \tau {\bar{\nu }}_{\tau }$ decays. Using the experimentally measured $q^2$-binned differential branching ratios of $B\to \pi \mu {\bar{\nu }}_{\mu }$ decay as input, employing the Bourrely-Caprini-Lellouch parametrization, we extract the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|=3.73(14)\times 10^{-3}$.

    hep-ph4 citations
22. 22*

    Application of $K\to 3\pi$ amplitudes to semileptonic kaon decays

    Anshika Bansal🇩🇪 · Jack Jenkins🇩🇪 · Daniel Winney🇩🇪

    We study dispersive representations of nonlocal form factors in $K^{+}\to {\pi }^{+}{\ell }^{+}{\ell }^{-}$ and $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ decays, with an aim of improving the theoretical description of the spectrum and decay rate of the neutrino mode. Based on unitarity, these representations invoke the $K^{+}{\pi }^{-}\to {\pi }^{+}{\pi }^{-}$ amplitude in $P$-wave and the pion vector form factor. The $P$-wave amplitude can be effectively parameterized within the dispersive Khuri-Treiman framework, and constrained by experimental information on the CP-conserving $K^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}$ and $K^{+}\to {\pi }^0{\pi }^0{\pi }^{+}$ decays. We also emphasize certain relations between charged-lepton and neutrino non-local form factors based on the Operator Product Expansion, which can be used to impose further phenomenological constraints.

    hep-ph0 citations
23. 23*

    Scalar-Mediated Inelastic Dark Matter as a Solution to Small-Scale Structure Anomalies

    Zihan Wang🇬🇧

    We propose a scalar-mediated Self-Interacting Dark Matter (SIDM) model to address small-scale structure anomalies such as the core-cusp and diversity problems. The model is composed by a leptophilic scalar mediator and a pseudo-Dirac dark matter candidate with a mass splitting of 100ev.We imposed a dark discrete ${\mathbb{Z}}_2$ symmetry forbids tree-level elastic scattering. Therefore creates kinematic threshold that suppresses scattering in ultra-faint satellite galaxies while enabling large self-interaction cross-sections in dwarf galaxies via resonant enhancement. To satisfy Big Bang Nucleosynthesis (BBN) requirements, we introduce a dimension-5 magnetic dipole operator that enable the decay of the excited state (${\chi }_2\to {\chi }_1\gamma$). This operator also provides a unique, low-threshold signal for direct detection experiments, characterized by a distinct $1/E_R$ recoil spectrum. We identify a benchmark parameter space around ($m_{\chi }\approx 40$ GeV, $m_{\varphi }\approx 20$ MeV) where non-perturbative coupled-channel dynamics successfully reconcile astrophysical observations with cosmological bounds, including CMB constraints on annihilation.

    hep-phastro-ph.COPRD(2026)·5 citations
24. 24*

    Searching for Ultralight Dark Matter with Mössbauer Resonance

    Peng-Long Zhang🇨🇳 · Yu-Ming Yang🇨🇳 · Xiao-Jun Bi🇨🇳 · Qin Chang🇨🇳 · Yu Gao🇨🇳 · Hai-Bo Li🇨🇳 · Wei Xu🇨🇳 · Peng-Fei Yin🇨🇳

    We investigate the feasibility of probing the interactions between ultralight scalar dark matter and atomic nuclei using a stationary Mössbauer spectroscopy scheme. The exceptional energy resolution of the Mössbauer resonance enables searches for tiny nuclear energy shifts induced by the local dark matter field. The dark matter mass range considered in this work is $10^{-18}$--$10^{-8}\mathrm{eV}$. We present projected constraints for two candidate Mössbauer isotopes, ${}^{109}\mathrm{Ag}$ and ${}^{45}\mathrm{Sc}$, with ${}^{109}\mathrm{Ag}$ providing the strongest sensitivity. For ${}^{109}\mathrm{Ag}$, projected sensitivities as low as approximately $10^{-19}$, $10^{-22}$, and $10^{-21}\mathrm{Ge}{\mathrm{V}}^{-1}$ can be achieved for the scalar DM--photon, DM--gluon, and DM--quark couplings $f_{\gamma }^{-1}$, $f_g^{-1}$, and $f_{\hat{m}}^{-1}$, respectively. In the low-mass region, the projected sensitivity to the scalar DM--photon coupling approaches the current constraints from equivalence-principle (EP) tests. These results demonstrate that Mössbauer-based techniques provide a promising and competitive approach for probing ultralight dark matter interactions with Standard Model particles.

    hep-ph0 citations
25. 25*

    Hydrodynamic Short-Range Correlations from Boltzmann-Langevin Equation

    Li Yan🇨🇳 · Derek Teaney🇺🇸

    We investigate hydrodynamic contributions to short-range two-particle correlations in relativistic heavy-ion collisions using the Boltzmann-Langevin equation. We derive and solve the transport equation for equal-time two-point correlations, obtaining both local and non-local contributions that scale with transport coefficients. The non-local correlations emerging from 2-to-2 scattering dynamics provide a hydrodynamic signature in short-range correlation measurements.

    hep-phnucl-exnucl-thEPJ Web Conf.(2026)·0 citations
26. 26*

    Gravitational Production of Massive Spin-2 Particles During Reheating

    Sarunas Verner🇺🇸

    We study the minimal gravitational portal for a massive spin-2 dark matter candidate $X_{\mu \nu }$ produced during perturbative reheating. The dark sector couples to the visible sector only via gravity, and we analyze two unavoidable channels: (i) inflaton condensate annihilation, $\varphi +\varphi \to X+X$, and (ii) thermal scatterings, $\mathrm{SM}+\mathrm{SM}\to X+X$, both mediated by graviton exchange. Working in the Fierz-Pauli framework for a free massive spin-2 field of mass $m_2$, we derive the graviton-mediated amplitudes and perform a full helicity decomposition of the final state. The relic abundance is obtained analytically in terms of $m_2$ and the reheating temperature $T_{\mathrm{RH}}$. In the light mass regime $m_2\ll m_{\varphi }$ (with $m_{\varphi }$ the inflaton mass during oscillations), production is overwhelmingly dominated by the longitudinal (helicity-0) mode: the $2\to 2$ cross section is parametrically enhanced, scaling as $\sim (m_{\varphi }/m_2{)}^4$, and yields efficient dark matter production despite purely gravitational couplings. Compared to lower-spin cases (spin-$0$, $1/2$, $1$, and $3/2$), massive spin-$2$ production is substantially more efficient for the same reheating history. Over most of the parameter space the inflaton condensate channel dominates the yield, while the thermal contribution is negligible. Avoiding overproduction typically requires either a relatively low $T_{\mathrm{RH}}$ or a spin-$2$ mass near threshold, $m_2\lesssim m_{\varphi }$. This places the spin-$2$ portal on similar footing to other higher spins in reheating scenarios, while emphasizing the central role of the helicity-$0$ mode and the reheating history in setting the dark matter density.

    hep-phastro-ph.COhep-thPRD(2026)·2 citations
27. 27*

    Spin density matrix of baryon-antibaryon pairs in electron-positron annihilation with $P$ and $CP$ violation including electron mass

    Chun-Qiu Zhao🇨🇳 · Xu Cao🇨🇳 · Jian-Ping Dai🇨🇳

    In the center-of-mass frame, the spin density matrix for octet baryon-antibaryon pairs produced in polarized electron-positron annihilation is unambiguously determined within the one-photon-exchange approximation. The formalism simultaneously incorporates parity ($P$) and combined parity-charge conjugation ($CP$) violation arising from the coupling of the intermediate virtual photon to the baryon pair. The finite electron mass is explicitly accounted for as a correction to these $P$ and $CP$ violating effects. Built on the spin projection operator, the derived full and compact spin density matrix provides a natural starting point for evaluating other quantities of physical interest -- particularly angular distributions of sequential decays and the quantum entanglement of hyperon pairs.

    hep-ph5 citations
28. 28*

    The Standard Model Prediction for the Rare Decay $B\to X_s\nu \bar{\nu }$

    Matteo Fael🇮🇹 · Jack Jenkins🇩🇪 · Enrico Lunghi🇺🇸 · Zachary Polonsky🇨🇭

    We present updated and comprehensive Standard Model predictions for the inclusive rare decay $B\to X_s\nu \bar{\nu }$. Using a state-of-the-art determination of the short-distance coefficient, including NLO QCD and electroweak effects, and implementing a consistent treatment of heavy-quark masses and power corrections within the kinetic scheme, we compute the total decay rate and the neutrino invariant mass spectrum. We incorporate all known perturbative contributions in the heavy quark limit up to $\mathcal{O}({\alpha }_s^3)$, evaluate non-perturbative corrections through the Heavy Quark Expansion up to $1/m_b^3$, and include estimates of four-quark operator matrix elements from HQET sum rules. We obtain the Standard Model branching ratios $\text{Br}(B^0\to X_s\nu \bar{\nu })=(3.35\pm 0.10)\times 10^{-5}$ and $\text{Br}(B^{+}\to X_s\nu \bar{\nu })=(3.62\pm 0.11)\times 10^{-5},$ representing a significant improvement in both central value and precision compared to previous determinations. We also provide predictions for partial rates with kinematic cuts relevant to Belle II. Our results are timely in view of recent measurements of $B\to K\nu \bar{\nu }$ and the first upper limits on inclusive $B\to X_s\nu \bar{\nu }$, and they offer a robust baseline for future searches for physics beyond the Standard Model in $b\to s\nu \bar{\nu }$ transitions.

    hep-phhep-exJHEP(2026)·8 citations
29. 29*

    Assessing the impact of the electron ion collider in China on Deeply Virtual Compton Scattering

    Yuan-Yuan Huang🇨🇳 · Xu Cao🇨🇳 · Taifu Feng🇨🇳 · Krešimir Kumerički🇭🇷 · Yu Lu🇨🇳

    We assess the impact of future measurements of deeply virtual Compton scattering (DVCS) off protons using the planned detector at the Electron-Ion Collider in China (EicC), proposed as an upgrade to the High Intensity heavy-ion Accelerator Facility (HIAF). We develop a neural-network architecture to flexibly parameterize the Compton Form Factors (CFFs), extrapolate reliably into unmeasured kinematic regions, and provide robust uncertainty estimates through the replica method. The framework is fitted to the available worldwide DVCS data using the Gepard software. We find a significant reduction in the uncertainties of all CFFs after incorporating pseudo-data from single and double polarization asymmetries at the EicC, with particularly strong improvements in the sea-quark region.

    hep-phCPC(2026)·1 citation
30. 30*

    Search for Light Neutral Scalar in the Georgi-Machacek Model with Forward Detectors at the LHC

    Yuanqian Fang🇨🇳 · Wei Su🇨🇳 · Xinyu Wang🇨🇳 · Yongcheng Wu🇨🇳 · Yan Zhang🇨🇳

    Long-lived particle (LLP) is one of the well-motivated targets for current collider experiments searching for the physics beyond the Standard Model. In recent years, many dedicated detectors have been developed for such scenarios which are designed to extend the sensitivity to weakly coupled particles with macroscopic $c\tau$. In this work, we investigate the LLP signatures of the neutral component of the fermiophobic fiveplet $H_5^0$ in the Georgi-Machacek model. Due to its fermiophobic nature at tree level, it possesses suppressed decay widths in the low mass region and can naturally be long-lived over a wide region of parameter space. We show that $H_5^0$ can be produced with an appreciable flux in the forward region from the meson decay through loop-induced couplings leading to observable LLP signatures in forward detectors. We evaluate the sensitivity of representative forward detectors to this scenario and compare the result with existing constraints from terrestrial experiments and astrophysical observations. Our results demonstrate that the forward detectors can probe the $s_H$ down to $\mathcal{O}(10^{-5})$ for sub-GeV scalar masses, and hence providing a powerful and complementary probe of the extended Higgs sectors that is inaccessible to conventional searches.

    hep-phhep-thJHEP(2026)·2 citations
31. 31*

    Investigations on heavy quarkonium hybrid mesons with exotic quantum numbers $J^{PC}=2^{+-}$

    Qi-Nan Wang🇨🇳 · Ding-Kun Lian🇨🇳 · Hua-Xing Chen🇨🇳 · Wei Chen🇨🇳

    We investigate the heavy quarkonium hybrid mesons with exotic quantum numbers $J^{PC}=2^{+-}$ via QCD sum rule method. We construct the currents with three Lorentz indices and calculate the correlation functions up to dimension six at the leading order of ${\alpha }_s$. The states with $J^{PC}=2^{+-}$ are extracted by constructing the corresponding projection operators. The obtained results indicate that the masses of $2^{+-}$ $\bar{c}Gc$ and $\bar{b}Gb$ hybrid states are about $4.49\mathrm{GeV}$ and $10.48\mathrm{GeV}$, respectively. We suggest to search for $\bar{c}Gc$ hybrid meson with $J^{PC}=2^{+-}$ in $J/\psi f_{0,1,2}$ and ${\chi }_{c0,1,2}\omega$ final states.

    hep-phPLB(2026)·0 citations
32. 32*

    Constraining the proton transverse partonic distribution through coherent diffractive $J/\psi$ production at HERA within a static Gaussian hot spot model

    Muhammad Raihannafi Fadhel🇮🇩 · Chalis Setyadi🇮🇩

    We investigate the transverse parton distribution of the proton through the t-dependence of the coherent J/psi differential cross section extracted from HERA measurements in the small-x regime. Employing a simple static Gaussian hot spot model inspired by the large-x three-valence-quark picture of the proton, we introduce three geometric degrees of freedom of each hot spot: the Gaussian width of each hot spot, the spatial distance of the valence quarks from the proton center, and their azimuthal orientation. In the simplest implementation, the valence quarks are assumed to form a symmetric triangular configuration. We find that variations in these geometric structures significantly influence the t-slope of the coherent cross section. In particular, the rotational degree of freedom strongly affects the cross section at t > 0.5 GeV^2, while the small-t region remains largely insensitive to variations in this parameter.

    hep-ph0 citations
33. 33*

    In-in formalism with resummmation in a constant electric field: propagators including nontrivial boundary wavefunctions

    Kenji Fukushima🇯🇵 · Shuhei Minato🇯🇵

    We present the derivation of an alternative representation of the real-time in-in formalism under a spatially homogeneous and time independent electric field. Because the system exhibits instability associated with pair production of particles and antiparticles, the perturbation theory should be reorganized depending on the choice of the reference vacuum. We recast the boundary wavefunctions into the quadratic self-energy-like terms in the functional integration formalism. The resulting generating functional in the modified in-in formalism leads to the propagators that resum infinite diagrams necessary to capture the vacuum-instability effects. The proper-time representations of the propagators reproduce the known expressions from the canonical operator formalism, but our derivation based on the generating functional along the closed-time path clarifies the origin of the additional proper-time contour and provides a better physical understanding. Finally, as a concrete example of the application, we compute the in-in expectation value of the vector current in a constant electric field, and find that the simple one-loop calculation captures the pair production effect.

    hep-phhep-thJHEP(2026)·5 citations
34. 34*

    On the inclusion of the pion form factor in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ beyond leading order

    Francesco P. Ucci🇮🇹

    The pion form factor plays a crucial role in the determination of the contribution of the hadronic vacuum polarisation to the muon anomalous magnetic moment. In order to measure this quantity, energy-scan experiments rely on Monte Carlo generator to simulate the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}(\gamma )$ process. For the theoretical accuracy to match the experimental precision, next-to-leading order calculations and the resummation of multiple photon emissions are needed. In this context, the inclusion of the pion form factor beyond the leading order approximation is crucial to reproduce some observables, like the pion charge asymmetry. We present the impact of the inclusion of the pion form factor in loop diagrams with three approaches and the interplay with radiative corrections.

    hep-phNuovo Cim.C(2026)·0 citations
35. 35*

    On the new physics in Bhabha luminometry at future $e^{+}{e}^{-}$ colliders

    Clara L. Del Pio🇺🇸 · Francesco P. Ucci🇮🇹

    The absolute machine luminosity is a key quantity to achieve the high-precision physics program of future $e^{+}{e}^{-}$ collider. It is determined by measuring a theoretically well-known process, which, ideally, can be computed with arbitrary precision in the perturbation theory. However, yet undiscovered new physics could give a non-negligible contribution to the cross section of the luminosity monitoring process, thus invalidating the uncertainty determination of measured quantities. We assess the theoretical error of non-Standard Model origin to the small-angle Bhabha scattering in various future colliders scenarios. In addition, a possible running strategy to constrain unknown heavy interactions is proposed, relying on asymmetries that do not depend on the absolute luminosity.

    hep-phNuovo Cim.C(2026)·0 citations
36. 36*

    Semileptonic neutral current decays of ${\Xi }_b$ with dileptons or dineutrinos in the final state

    Zhou Rui🇨🇳 · Zhi-Tian Zou🇨🇳 · Ya Li🇨🇳 · Ying Li🇨🇳

    We perform a detailed analysis of semileptonic ${\Xi }_b$ decays mediated by flavor-changing neutral currents ($b\to s$ and $b\to d$) with dilepton or dineutrino final states within the perturbative QCD framework. All independent form factors including vector, axial-vector, tensor, and pseudotensor currents are calculated and are used to analyze the decay branching fractions and angular distributions. Our numerical results for the branching fractions of ${\Xi }_b\to \Xi {\ell }^{+}{\ell }^{-}$ decays suggest they are within measurable reach for the LHCb experiment in the near future. Furthermore, we show that a measurement of the ratio $\mathcal{B}({\Xi }_b^{-}\to {\Sigma }^{-}{\mu }^{+}{\mu }^{-})/\mathcal{B}({\Xi }_b^{-}\to {\Xi }^{-}{\mu }^{+}{\mu }^{-})$ will allow for an independent determination of $|V_{td}/V_{ts}|$. For the case of unpolarized ${\Xi }_b$ baryons, we derive several angular observables, which can provide new and complementary constraints on Wilson coefficients in semileptonic FCNC transitions compared to those from mesonic decays. Finally, we present a combined analysis of dilepton and dineutrino channels, comparing various observables in detail. Our results offer further insights into the long-standing anomalies observed in $B$ meson decays.

    hep-phPRD(2026)·1 citation
37. 37*

    Double Resonance Strategy for Interferometric Detection of Axions

    Spencer Green🇺🇸 · Frank Wilczek🇺🇸

    We propose a double-resonant interferometric strategy for axion dark matter detection that combines microwave circuit resonance with Fabry--Pérot optical enhancement. In a strong magnetic field, axion--photon mixing induces a weak oscillating electric field, which is first amplified by a resonant circuit and then transduced into an optical phase shift via the electro-optic effect. Multiple coherent optical passes through the electro-optic medium accumulate this phase shift, enabling interferometric readout using mature optical techniques. We present the basic operating principle, discuss material requirements, and estimate the achievable sensitivity. For representative parameters, the projected reach extends into the parameter space of well-motivated QCD axion models.

    hep-ph1 citation
38. 38*

    Analytical study of birefringent cavities for axion-like dark matter search

    Tadashi Kuramoto🇯🇵 · Yasutaka Imai🇯🇵 · Takahiko Masuda🇯🇵 · Yutaka Shikano🇯🇵 · Sayuri Takatori🇯🇵 · Satoshi Uetake🇯🇵

    Light polarization plays a crucial role in optical-cavity experiments; however, mirror birefringence presents a significant challenge that must be addressed carefully. In this study, a rigorous, nonperturbative framework is developed to quantify birefringence effects by incorporating variations in reflectance and polarization misalignment. We analyze the impact of this framework on the sensitivity of axion-like particle (ALP) dark-matter searches. The results show that both birefringence and misalignment contribute to sensitivity degradation in the low-mass regime; however, the adverse effects of misalignment can be mitigated by selecting a postselection angle greater than the misalignment angle. Furthermore, birefringence produces an additional resonance peak in the high-mass region, which remains largely unaffected by misalignment and postselection variations. This rigorous framework underscores the importance of considering birefringence in high-precision optical-cavity experiments for ALP detection.

    hep-phgr-qcquant-phPRD(2026)·0 citations
39. 39*

    Probing Dark Sectors with Exploding Black Holes: Gamma Rays

    Michael J. Baker🇺🇸 · Joaquim Iguaz Juan🇺🇸 · Aidan Symons🇺🇸 · Andrea Thamm🇺🇸

    The Hawking radiation from the explosion of a black hole would provide definitive information on the particle spectrum of nature. Here we quantify the potential of current and future gamma ray telescopes to probe new dark sectors. We improve on the analysis used in previous work by making careful use of the experimental response functions, deriving a more realistic estimate of the backgrounds and optimizing the statistical analysis. We compute the sensitivity of the current experiments (HAWC and LHAASO) and estimate the reach of the future experiments (SWGO and CTA North and South), for various sky positions of the explosion. We find that for a black hole exploding at $0.01\text{pc}$ the gamma ray signal observed by HAWC could probe dark sectors with 10-20 (or more) new Dirac fermions up to masses around $10^5\text{GeV}$, while CTA will be able to probe 2-15 new Dirac fermions with masses up to $10^6\text{GeV}$. CTA North and South will have sensitivity to 10 dark fermions up to a distance of 0.1 pc and 50 up to a distance of 0.6 pc.

    hep-phastro-ph.COastro-ph.HEJHEP(2026)·6 citations
40. 40*

    Search for Quadruplet Scalars using Boosted Decision Trees at the LHC

    Amit Chakraborty🇮🇳 · Shreecheta Chowdhury🇮🇳 · Nilanjana Kumar🇮🇳 · Vandana Sahdev🇮🇳

    Beyond the Standard Model scenarios introduce additional scalar and fermion multiplets, which influence neutrino mass generation mechanisms and yield distinctive collider signatures. This work focuses on a particular scenario involving a fermion quintuplet and a scalar quadruplet. The study examines the production and decay of the scalar quadruplet components at the Large Hadron Collider (LHC), emphasizing how their decay patterns, fermiophobic versus fermiophilic, depend on mass differences and Yukawa couplings with the fermion multiplets. This study provides an overview of possible signals at the LHC, along with a detailed collider analysis focused on final states containing at least four leptons and two jets, in which the masses of the scalars and fermions are reconstructed successfully. Standard Model backgrounds are also incorporated in the study, with multivariate techniques leveraged via Boosted Decision Trees. Results indicate discovery potential for scalar masses around 600-700 GeV and exclusion sensitivity extending beyond 1 TeV, highlighting the promising experimental signatures of the model and its role in probing new physics at colliders.

    hep-phPRD(2026)·2 citations
41. 41*

    Heavy neutral bosons and dark matter in the 3-3-1 model with axionlike particle

    T.T. Hieu🇻🇳 · V.H. Binh🇻🇳 · H. N. Long🇻🇳 · H. T. Hung🇻🇳

    We consider heavy neutral bosons in the 3-3-1 model with axionlike particles (331ALP), including the Higgs boson and the $Z^{\prime }$ boson which are outside the standard model (SM). Based on gluon-gluon fusion at the LHC, we investigate the signals of cross-sections in the parameter space region satisfying the current experimental limits of lepton flavor violating decay, including processes involving both charged leptons and Higgs boson, and provide predictions of $m_{h_2}\ge 630\mathrm{GeV}$. A new gauge boson, labeled as $Z^{\prime }$, has its mass excluded in the smaller domain $5.1\mathrm{TeV}$ based on investigating the cross-section of the processes that $Z^{\prime }$ mediates combined with experimental limits of the search for high-mass dilepton resonances at ATLAS and CMS. We consider the stability of odd-$Z_2$ particles, with $Z_2$ is assumed a residual symmetry after spontaneous symmetry breaking stages, to point out dark matter candidates in the model. Investigating the relic density of dark matter within experimentally permissible limits, we established a relationship between the mass of dark matter and the breaking scale of axion.

    hep-ph2 citations
42. 42*

    A Composite Theory of Higgs and Flavour

    Joe Davighi🇨🇭 · Gino Isidori🇨🇭

    We introduce a composite Higgs model in which a flavour deconstructed gauge group is embedded in the strong sector. The pattern of global symmetry breaking yields, as pseudo-Nambu-Goldstone (pNGB) bosons, both a Standard Model (SM)-like Higgs and the link field whose vacuum expectation value breaks the flavour non-universal gauge group down to the SM. Inevitably, a third pNGB appears, transforming as a second Higgs doublet coupled only to the light generations. This heavy Higgs naturally mediates suppressed light Yukawa couplings, providing a solution to the flavour puzzle. At the same time, new physics contributions to flavour violating observables are CKM- and chirally suppressed, while electric dipole moment bounds are evaded through an automatic mass alignment in the light fermion sector. The result is a natural framework for addressing the origin of both Higgs and flavour hierarchies, with reduced Higgs mass tuning and minimised impact in flavour observables, that is best tested by high-$p_T$ and precision electroweak measurements.

    hep-ph7 citations
43. 43*

    CT25: Progress toward next-generation PDFs for precision phenomenology at the LHC

    A. Ablat🇨🇳 · A. Courtoy🇲🇽 · S. Dulat🇨🇳 · Y. Fu🇨🇳 · M. Guzzi🇺🇸 · T. J. Hobbs🇺🇸 · J. Huston🇺🇸 · K. Mohan🇺🇸 · P. Nadolsky🇺🇸 · M. Ponce-Chavez🇺🇸 · D. Stump🇺🇸 · K. Xie🇨🇳 · C.-P. Yuan🇺🇸

    We summarize recent progress toward the next generation of CTEQ-TEA parton distribution functions, CT25, based on a global NNLO analysis that incorporates a significant sample of newly included LHC data. We present a baseline fit within the forthcoming full CT25 fit, which includes new Drell-Yan, top-pair, and inclusive-jet data at 8 and 13 TeV, and exhibits non-trivial pulls on the high-$x$ gluon and the flavor structure of the quark sea. In the context of progress toward CT25, we also summarize several recent and ongoing studies of the interplay between phenomenological PDFs and lattice-QCD calculations, simultaneous extractions of ${\alpha }_s(M_Z)$ within the CT framework, and an expanded program of uncertainty quantification that treats parametrization dependence as an explicit source of epistemic uncertainty, among other issues. We also briefly highlight CT efforts to understand the effects of partial implementations of N${}^3$LO corrections into PDF fits, which include benchmark calculations for Higgs and vector-boson processes. We comment on the implications of recent improvements to the CT analysis for precision phenomenology at the LHC and future facilities.

    hep-phhep-exnucl-th5 citations
44. 44*

    $N_{\text{eff}}$ Constraint on Pseudo-Dirac Neutrinos

    Chee Sheng Fong🇧🇷 · Yago Porto🇧🇷

    After the electroweak symmetry breaking, we can write down two types of mass for the Standard Model neutrinos, Dirac or Majorana. It is often said that both types of mass cannot be distinguished in neutrino oscillation phenomena. This is in fact not true if neutrinos are pseudo-Dirac (strictly speaking still Majorana) where they mix almost maximally with sterile neutrinos to form pseudo-Dirac pairs. If this is indeed realized in Nature, what we observe experimentally as three mass eigenstates are actually three pairs of mass eigenstates with yet-to-be-measured new mass splitting among each pair. While the new mass squared splitting of the first and second mass eigenstates have stringent constraints from solar neutrino to be $|\delta m_{1,2}^2|\lesssim 10^{-11}{\text{eV}}^2$, the one regarding the third mass eigenstate has a weaker constraint $|\delta m_3^2|\lesssim 10^{-5}{\text{eV}}^2$. By keeping only one nonzero pseudo-Dirac mass squared splitting at a time, we derive an effective 3+1 description for the pseudo-Dirac scenario. Then we use the Cosmic Microwave Background (CMB) constraint on neutrino relativistic degrees of freedom $N_{\text{eff}}$ to derive a new constraint $|\delta m_3^2|<2\times 10^{-6}{\mathrm{eV}}^2$ and show that the future CMB-S4 and CMB-HD can improve this bound by an order of magnitude.

    hep-phastro-ph.CO1 citation
45. 45*

    Shifting the neutrino fog: studying the Isospin-violating Dark Matter case

    Laura Duque🇲🇽 · J. M. Lamprea🇲🇽 · Omar G. Miranda🇲🇽

    First observation of solar neutrinos through coherent elastic neutrino-nucleus scattering by dark matter (DM) direct detection (DD) experiments makes the study of the neutrino fog of the most relevance. This irreducible neutrino background depends on the target material as well as other experimental parameters. Recently, it has also been remarked the dependence of the neutrino fog on the DM models under consideration. In this work, we study the case of Isospin-violating dark matter (IVDM) models, discussing specific examples of DM models and making a detailed analysis of the implications of IVDM on the neutrino fog. We also explore the conditions under which this background can be mitigated for specific DM models.

    hep-phPRD(2026)·1 citation
46. 46*

    Coherent Elastic Neutrino-Nucleus Scattering at the Japan Proton Accelerator Research Complex

    J.I. Collar🇺🇸 · Ivan Esteban🇪🇸 · J.J. Gomez-Cadenas🇪🇸 · M.C. Gonzalez-Garcia🇺🇸 · L. Ji🇪🇸 · L. Larizgoitia🇪🇸 · C.M. Lewis🇺🇸 · F. Monrabal🇪🇸 · João Paulo Pinheiro🇨🇳 · A. Simón🇪🇸 · S.G. Yoon🇺🇸

    The Japan Proton Accelerator Research Complex (J-PARC) currently delivers a 1 MW, 3 GeV proton beam to the Materials and Life Science Experimental Facility (MLF). Power is expected to increase to 1.3 MW, driven by the needs of Hyper-Kamiokande. As a result, the MLF presently provides the highest neutron yield of any spallation source, while potentially holding the best current and foreseeable conditions for Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) experimentation. We explore this potential, using as examples detector technologies presently funded for construction and under development. We quantify their sensitivity to a rich variety of particle physics scenarios, finding that very-high-statistics CE$\nu$NS measurements with significant sensitivity to relevant scenarios are feasible at this facility within the next few years.

    hep-phhep-exJHEP(2026)·5 citations
47. 47*

    Residual Symmetries and Scalar Multiplet Vacuum Alignment in Non-Abelian Flavour Models

    Ivo de Medeiros Varzielas🇵🇹 · Ming-Shau Liu🇬🇧 · Amartya Sengupta🇺🇸 · Jim Talbert🇺🇸

    We demonstrate that, upon minimizing a renormalizable, single-scalar potential invariant under a non-Abelian symmetry, special orientations in the associated vacuum alignment of the scalar multiplet correspond to the preservation of a discrete residual flavour symmetry in the broken phase of the theory. Conversely, we show that these special scalar alignments are perturbed when additional Lagrangian operators (e.g. renormalizable, multi-flavon operators and/or effective, higher-dimensional operators) are present that break said residual symmetry, leading to a vacuum reorientation and phenomenological consequences. We therefore construct a one-to-one correspondence principle between broken residual symmetries and vacuum alignment corrections, providing a mechanism to identify (and correct) a subtle but persistent form of phenomenologically relevant fine-tuning embedded in -- but often ignored by -- most successful non-Abelian flavour models. We first establish this correspondence in a set of toy models based on the S4 permutation symmetry, and then apply the lessons learned to the more realistic A4 Altarelli-Feruglio and $\Delta (27)$ Universal Texture Zero models.

    hep-phJHEP(2026)·9 citations
48. 48*

    Probing invisible particles with charm

    Gudrun Hiller🇩🇪 · Dominik Suelmann🇩🇪

    We point out opportunities to probe invisible particles, left- and right-handed neutrinos, axion-like particles (ALPs) and dark photons $(Z^{\prime })$ with rare decays of charm hadrons. We employ and recast existing searches in $D\to (\pi ,\omega )X$, $D^0\to X$ and ${\Lambda }_c\to pX$, where $X$ denotes one of the above invisible final states including dineutrinos. The branching ratios are clean null tests of the standard model, yet, are essentially unconstrained for some parameters of light new physics, limited only by weak lifetime constraints at the level of $\mathcal{O}(10^{-1})$. On the other hand, if models are probed, branching ratios still reach up to $10^{-3}$ ($Z^{\prime }$) and $10^{-4}$ (ALPs). Chirality-preserving operators from heavy new physics in the dimension six standard model effective theory (SMEFT) imply tighter upper limits, up to few $\times 10^{-5}$. Constraints on chirality-flipping heavy new physics, such as lepton number violation from dimension seven SMEFT, or with light sterile neutrinos, are weaker, with branching ratios up to few$\times 10^{-4}$. Sensitivities to different couplings arise with ${\Lambda }_c\to pX$ and $D\to \pi \pi X$ decays, in particular in relation with the other modes. Processes can be studied at running and future experiments with high charm luminosities, BESIII, Belle II, a super-tau-charm factory (STCF) and $Z$-factories, such as the FCC-ee and the CEPC.

    hep-phhep-exPRD(2026)·4 citations
49. 49*

    Multiple Mellin-Barnes integrals with polygamma functions

    Sumit Banik🇨🇭 · Samuel Friot🇫🇷

    Mellin-Barnes (MB) integrals appear in various branches of physics and mathematics and are, in particular, used as a standard tool for evaluating multi-loop, multi-scale Feynman integrals both analytically and numerically. Recent geometric approaches based on conic hulls and triangulations provide a systematic framework for computing multiple MB integrals in terms of multivariate series. These approaches have so far been limited to MB integrals whose integrands are ratios of products of Euler's gamma functions only. However, in Feynman integral calculus, MB integrals with polygamma functions naturally arise, for instance, after resolving singularities in the dimensional-regularisation parameter $ϵ$ and expanding the MB integrand in powers of $ϵ$, as done by the public codes MB.m and MBresolve.m. In this paper, we extend the conic hull and triangulation methods to the computation of MB integrals having polygamma functions in their integrand. We show that the arguments of polygamma functions can be treated in a similar way to the arguments of gamma functions when applying the conic hull and triangulation techniques to identify poles that would contribute to different series solutions. However, since the singularity structure of the polygamma function is different from that of the gamma function, we propose two different ways to compute MB integrals involving polygamma functions, depending on whether the MB integral has straight or non-straight contours. We have implemented these algorithms in an updated version of the Mathematica package MBConicHulls.wl, which can be found at https://github.com/SumitBanikGit/MBConicHulls/, and we illustrate their use with a set of examples from Feynman integral calculus.

    hep-phhep-thPRD(2026)·1 citation
50. 50*

    Temperature Dependence of the Masses of Various Meson States: A Comparative Study in SU(3) and SU(4) extended Linear-Sigma Model

    Alexandra Friesen (Dubna, JINR)🇷🇺 · Yu. Kalinovsky (Dubna, JINR)🇷🇺 · Saleh O. Allehabi (Islamic U. Madinah)🇸🇦 · Norhan M. Rfeek (Assiut U.)🇪🇬 · Azzah A. Alshehri (Egyptian Ctr. Theor. Phys., Cairo and Hafr El Batin U.)🇪🇬 · Abdel Nasser Tawfik (Islamic U. Madinah and Ahram Canadian U. and Egyptian Ctr. Theor. Phys., Cairo and WLCAPP, Cairo)🇸🇦

    In the extended Linear-Sigma Model (eLSM), the chiral phase structure of meson states, including pseudoscalars ($J^{pc}=0^{-+}$), scalars ($J^{pc}=0^{++}$), vectors ($J^{pc}=1^{--}$), and axial-vectors ($J^{pc}=1^{++}$), is investigated with the mean-field approximation. A systematic comparison between SU(3) and SU(4) configurations is provided. It has been found that the estimations of meson masses derived from SU(4) eLSM are more congruent with experimental values than those derived from SU(3) eLSM. Consequently, we conclude that an increase in quark degrees of freedom significantly enhances the accuracy of meson mass simulations. We investigate the effect of temperature on the masses of various meson states calculated in the SU(3) and SU(4) eLSM. After establishing all the fitting parameters, the temperature dependence of meson masses shows that although various meson states exhibit unique patterns in their mass changes with temperature, they all seem to share a similar range of dissolution temperatures. This means that the critical temperature that marks the phase transition from hadrons to quarks appears to vary slightly depending on the meson states. In this regard, we find that the quarkonium states, formed by a quark and its antiquark, are largely unaffected by variations in the temperature.

    hep-phhep-th0 citations
51. 51*

    Constrained Gaussian-process bridge prior for neutron-star equation-of-state inference

    Tyler Gorda🇺🇸 · Oleg Komoltsev🇳🇴 · Aleksi Kurkela🇳🇴 · Eirik Sunde🇳🇴

    We set forth a new method for generating model-agnostic, nonparametric priors for neutron star equation-of-state inference that are stable, causal and thermodynamically consistent by construction. This generalizes Gaussian processes to include global thermodynamic constraints, specifically allowing the inclusion of any number of training points in the form $(\mu ,n,p)$ while retaining thermodynamic consistency between them. The method is based on constructing constrained Gaussian-process bridges, whose correlation properties can be tuned at will allowing flexibility between a conservative prior and a theory-informed prior. The method does not require any shooting to obey multiple constraints and provides an efficient and informed way to include both chiral effective field theory and perturbative quantum chromodynamics constraints within the same framework.

    ↳ astro-ph.HEhep-phnucl-thApJ(2026)·12 citations
52. 52*

    Multiresolution analysis of quantum theories using Daubechies wavelet basis

    Mrinmoy Basak🇮🇳

    Flow equation methods, more generally known as Similarity Renormalization Group (SRG) techniques, were developed to address multiscale problems where multiple length or energy scales contribute simultaneously. In this Thesis, we formulate the flow equation method within a wavelet-based framework and apply it to study scale (resolution) separation in a two-dimensional scalar field theory. We demonstrate that the flow systematically block-diagonalizes the Hamiltonian with respect to wavelet resolution, achieving improved truncation compared to earlier studies. Using a model of two real scalar fields coupled through a quadratic interaction, we show that the flow equations effectively suppress couplings between low- and high-resolution degrees of freedom. This provides a clear mechanism for isolating low-resolution physics and offers insight into the construction of effective Hamiltonians using a wavelet-based flow equation approac

    ↳ hep-thhep-lathep-phphysics.comp-ph2 citations
53. 53*

    The chiral phase transition in the 3D Columbia plot

    Alessandro Sciarra🇩🇪

    The nature of the chiral phase transition of QCD continues to represent a fundamental open problem in the study of strongly interacting matter. In recent years, significant progress has been achieved by exploiting systematic variations of theory parameters in regimes free of the sign problem. In this work, the idea of a follow-up investigation that extends a previous study at zero chemical potential is presented. A concrete programme for such an extension is discussed, outlining the required numerical steps, from data production to final analysis, and pointing to all the software tools that have been released to support these studies.

    ↳ hep-lathep-ph0 citations
54. 54*

    Approximating Feynman Integrals Using Complete Monotonicity and Stieltjes Properties

    Sara Ditsch🇩🇪 · Johannes M. Henn🇩🇪 · Prashanth Raman🇩🇪

    We introduce two novel numerical approaches for computing Feynman integrals based on their complete monotonicity (CM) and Stieltjes properties. The first method uses that scalar Feynman integrals are CM, meaning that all their derivatives have a fixed sign, in the Euclidean kinematic region. This imposes strong constraints on the function space. Simultaneously, these integrals obey systems of linear differential equations with respect to kinematic parameters. By imposing that the solutions to these differential equations satisfy complete monotonicity across the Euclidean region, we develop an efficient and highly constraining numerical bootstrap method. We provide a proof of principle of the power of our approach by applying it to a class of multi-loop Feynman integrals with internal masses. The second method is based on a refinement of CM. We prove that Feynman integrals, within a certain range of parameters, such as dimension and propagator exponents, are not only CM but in fact Stieltjes functions. The latter can be described efficiently by Padé approximants that are known to converge in the cut complex plane. This means that these representations are valid also in analytically continued kinematics, such as physical scattering regions. These insights allow us to obtain rational approximations to Feynman integrals from minimal information, such as a Taylor expansion about a soft limit. We demonstrate the effectiveness of this method by applying it to a 20-loop banana-type Feynman integral. Finally, we comment on a number of extensions of these novel avenues for computing Feynman integrals.

    ↳ hep-thhep-phJHEP(2026)·6 citations
55. 55*

    Modular weights of wave functions on magnetized torus

    Tim Jeric🇯🇵 · Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵 · Maki Takeuchi🇯🇵 · Hikaru Uchida🇯🇵

    We study the origin of modular weights of wave functions in magnetized $T^2$ models. It is explicitly demonstrated that the modular weights of the wave functions on magnetized $T^2$ is equivalent to their mass level. We further extend this result to magnetized $T^{2g}$ models. As a result, we construct the wave functions of excited states in magnetized $T^{2g}$ models and show that their modular weights are likewise equivalent to the corresponding mass levels.

    ↳ hep-thhep-phJHEP(2026)·1 citation
56. 56*

    Dissociation-driven quarkonium spin alignment in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

    Bhagyarathi Sahoo🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳

    The observation of spin alignment of quarkonia in ultra-relativistic heavy-ion collisions provides deep insight into the possible formation of the quark-gluon plasma (QGP). The present study investigates the spin alignment of quarkonia induced by dissociation mechanisms arising from medium effects imposed on quarkonia. We implement an effective Hamiltonian with a medium-modified color-singlet potential to incorporate the coupling of quarkonium spin with medium vorticity. This coupling gives rise to spin-dependent dissociation, which we identify as a plausible mechanism contributing to quarkonium spin alignment. Within the ambit of second-order relativistic viscous hydrodynamics, we calculate the spin-dependent decay widths of charmonium ($J/\psi$, $\psi$(2S)) and bottomonium (${\rm Y}$(1S), ${\rm Y}$(2S)) in a rotating thermal medium, including collisional damping and gluonic dissociation effects. We evaluate the observable ${\rho }_{00}$ for Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV as a function of transverse momentum of the quarkonia, charged particle multiplicity, and medium rotation. The results demonstrate that medium vorticity modifies the quarkonia net decay width and, as a consequence, quarkonia spin alignment gets modified. These findings suggest new directions for understanding spin transport and the microscopic dynamics of vortical QGP.

    ↳ nucl-thhep-exhep-phhep-th+1PRD(2026)·1 citation
57. 57*

    Multi-neutron correlations in light nuclei via ab-initio lattice simulations

    Shuang Zhang🇩🇪 · Serdar Elhatisari🇸🇦 · Ulf-G. Meißner🇩🇪

    The quest to understand multi-neutron systems has a long history, and recent experimental efforts aim to probe candidate four-neutron configurations in neutron-rich light nuclei such as ${}^8$He and ${}^7$H via quasi-free knockout reactions. However, the ground-state energies of the hydrogen isotopes ${}^6$H and ${}^7$H are not yet well constrained, with substantial discrepancies across experimental analyses and theoretical predictions. Using ab initio nuclear lattice effective field theory with an ensemble of 282 chiral two- and three-nucleon forces, we perform a Bayesian uncertainty-quantified analysis of the ground-state energies of ${}^6$H and ${}^7$H. The marginal posteriors suggest single-neutron separation energy $S_n({}^7\mathrm{H})=0.35_{-0.32}^{+0.32}$ MeV, which kinematically disfavors sequential decay via ${}^6\mathrm{H}+n$ and thereby makes multi-neutron emission channels comparatively more relevant. Intrinsic densities indicate triton- and $\alpha$-like clusters in ${}^7$H and ${}^8$He, respectively. By computing two-body and reduced four-body correlation functions, we find that the valence neutrons in the surface region of these systems form compact dineutrons that predominantly organize into approximately symmetric dineutron-dineutron configurations, with only a small but non-negligible fraction assembling into more compact tetraneutron-like substructures. In ${}^7$H, these components account for roughly 95\% and 5\% of the sampled four-neutron configurations, respectively, and ${}^8$He exhibits a similar hierarchy. For these configurations, we also extract the corresponding spatial and angular correlation patterns among the nucleons. These results provide nuclear-structure insights into the debate surrounding four-neutron clusters and complement ongoing experimental searches for tetraneutron signatures in light nuclei.

    ↳ nucl-thhep-lathep-phnucl-ex4 citations
58. 58*

    Nuclear collectivity and the harmonic spectrum of two-body correlations

    Jean-Paul Blaizot🇫🇷 · Giuliano Giacalone🇨🇭 · Alessandro Lovato🇺🇸

    High-energy nuclear collisions have opened a new experimental method to reveal collective behavior in nuclear ground states through the lens of many-body correlations of nucleons. Using ab initio lattice and variational calculations of ${}^{20}$Ne and ${}^{16}$O, we study how emergent phenomena such as deformation or clustering can be identified in these systems from the dependence of their two-body density distributions on the relative azimuthal angle of nucleon pairs. A harmonic analysis of the correlation functions reveals in particular a dominant quadrupole component in ${}^{20}$Ne, consistent with a bowling-pin picture, and a prominent triangular modulation in ${}^{16}$O, possibly indicative of alpha-cluster correlations. Given that such structures can be accurately identified in high-energy collider experiments, these findings open a new paradigm for analyzing emergent collective behavior in atomic nuclei, relating their intrinsic shapes to the harmonic spectrum of microscopic correlations.

    ↳ nucl-thhep-exhep-phnucl-ex9 citations
59. 59*

    Quantum sensing of high-frequency gravitational waves with ion crystals

    Asuka Ito🇯🇵 · Ryuichiro Kitano🇯🇵 · Wakutaka Nakano🇯🇵 · Ryoto Takai🇯🇵

    A detection method for high-frequency gravitational waves using two-dimensional ion crystals is investigated. Gravitational waves can resonantly excite the drumhead modes of the ion crystal, particularly the parity-odd modes. In the optical dipole force protocol, entanglement between the drumhead modes and the collective spins transfers the excitation of the drumhead modes to the rotation of the total spin. Furthermore, gravitational wave detection beyond the standard quantum limit becomes possible as a squeezed spin state is generated through this entanglement. The sensitivity gets better with a larger ions crystals as well as a larger number of the ions. Future realization of large ion crystals can significantly improve the sensitivity to gravitational waves in the 10 kHz to 10 MHz region.

    ↳ gr-qchep-phphysics.atom-phquant-phJCAP(2026)·6 citations
60. 60*

    $f_K/f_{\pi }$ in iso-symmetric QCD and the CKM matrix unitarity

    Alessandro Conigli🇩🇪 · Julien Frison🇩🇪 · Alejandro Sáez🇪🇸

    We present lattice results for $f_K/f_{\pi }$ in the iso-symmetric limit of pure QCD (isoQCD) with $N_f=2+1$ flavours, along with a determination of $|V_{us}|/|V_{ud}|$ and a study on the unitarity of the first row of the Cabibbo-Kobayashi-Maskawa (CKM) matrix after introducing strong isospin-breaking and QED effects. The results obtained are based on a combination of a Wilson unitary action and the mixed-action setup introduced in arXiv:2309.14154, arXiv:2510.20450. The combination of the two regularisations enables a more precise control over the continuum-limit extrapolation.

    ↳ hep-lathep-phEPJC(2026)·1 citation
61. 61*

    Search for Axion-Like Particles from Nearby Pre-Supernova Stars

    Saurabh Mittal🇩🇪 · Thomas Siegert🇩🇪 · Francesca Calore🇫🇷 · Pierluca Carenza🇸🇪 · Laura Eisenberger🇩🇪 · Maurizio Giannotti🇪🇸 · Alessandro Lella🇮🇹 · Alessandro Mirizzi🇮🇹 · Dimitris Tsatsis🇩🇪 · Hiroki Yoneda🇩🇪

    Axion-like particles (ALPs) are hypothetical pseudoscalar bosons that arise in many extensions of the Standard Model and are well-motivated dark matter candidates. Nearby massive stars in the late stages of stellar evolution provide a promising environment for enhanced ALP production due to their high core temperatures and densities. We search for a combined signal of ALP-induced hard X-ray and soft $\gamma$-ray emission from 18 nearby pre-supernova stars using the full public 22-year INTEGRAL/SPI dataset, construct individual stellar spectra and link them in a coherent analysis. A maximum-likelihood approach is used to extract fluxes in the 20--2000 keV energy range. Stellar evolution models are employed to obtain the expected spectral shapes of ALP production processes peaking between 50--500 keV, depending on stellar mass and evolutionary stage. We construct a joint likelihood that incorporates uncertainties in stellar parameters to derive combined constraints on the coupling constants $g_{a\gamma }$ and $g_{ae}$ as a function of the ALP mass $m_a$. The hard X-ray and soft $\gamma$-ray fluxes of all selected stars are consistent with zero within uncertainties. We provide upper limits on the continuum emission and on the 511 keV and 1809 keV line fluxes. The combined upper limit on $g_{a\gamma }\times g_{ae}$ is $(0.008-2)x10^{-24}$ GeV${}^{-1}$ (95% C.I.) while the ALP-photon coupling is constrained to $g_{a\gamma }=(0.13-1.26)x10^{-11}$ GeV${}^{-1}$ (95% C.I.) for $m_a\leqq 10^{-11}$ eV, depending on the time to core collapse and magnetic field assumptions. Conservative limits of $(0.27-1.25)x10^{-24}$ GeV${}^{-1}$ (95% C.I.) are obtained assuming all but one star are in the early He-burning phase. These results rank among the strongest limits on ALP couplings to date and demonstrate the importance of soft $\gamma$-ray observations for probing ALPs and massive star evolution.

    ↳ astro-ph.HEastro-ph.SRhep-phAstron.Astrophys.(2026)·2 citations
62. 62*

    Measurement of Fifth- and Sixth-Order Fluctuations of (Net-)proton Number in Au+Au Collisions from Phase II of the Beam Energy Scan Program at RHIC

    The STAR Collaboration

    We report high-statistics measurements of fifth- and sixth-order factorial cumulants and cumulant ratios of (net-)proton multiplicity distributions in Au+Au collisions at $\sqrt{s_{NN}}=7.7$--27 GeV, using data from the STAR experiment collected during the Beam Energy Scan Phase~II at RHIC. Protons and antiprotons are identified at midrapidity ($|y|<0.5$) with transverse momentum $0.4<p_T<2.0$ GeV/$c$. The proton factorial cumulants ${\kappa }_4$, ${\kappa }_5$, and ${\kappa }_6$ increase with order but exhibit no sign alternation within current uncertainties, offering no evidence for a two-component structure in the proton multiplicity distribution, as might be expected near a first-order phase transition. The cumulant ratios $C_5/C_1$ and $C_6/C_2$ fluctuate around zero in collisions at 0--40\% centrality. The results are consistent with both the negative predictions from lattice QCD (LQCD) and the positive trends obtained from the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. At $\sqrt{s_{NN}}\gtrsim 27$ GeV, the $C_4/C_2$ and $C_5/C_1$ results are compatible with predictions from lattice QCD, functional renormalization group (FRG), and hadron resonance gas (HRG) models, while UrQMD describes the data better at lower energies. These measurements place constraints on baryon number fluctuations and offer valuable insights into the QCD phase structure.

    ↳ nucl-exhep-exhep-lathep-ph+1PRC(2026)·2 citations
63. 63*

    From $\mathrm{d}\log$ to $\mathrm{d}\mathcal{E}$: Canonical Elliptic Integrands and Modular Symbol Letters with Pure eMPLs

    Li Lin Yang🇨🇳 · Yiyang Zhang🇨🇳

    We propose '$\mathrm{d}\mathcal{E}$-forms' as fundamental building blocks of canonical integrands for elliptic Feynman integrals, which lead to Kronecker-Eisenstein $\omega$-form symbol letters. Built upon pure elliptic multiple polylogarithms, they provide a natural extension of the '$\mathrm{d}\log$-form' integrands and $\mathrm{d}\log$ letters for polylogarithmic cases. By introducing an extended basis treating all marked points equally, we manifest a hidden symmetry structure in the canonical connection matrix, and demonstrate its covariance under modular transformations. Our result provides a novel perspective on describing canonical bases and symbol letters in a unified language of pure functions.

    ↳ hep-thhep-ph5 citations
64. 64*

    Strong model-agnostic constraints for twin-star solutions

    Sofia Blomqvist🇫🇮 · Christian Ecker🇩🇪 · Tyler Gorda🇺🇸 · Aleksi Vuorinen🇫🇮

    We perform a model-agnostic Bayesian analysis of the neutron-star-matter equation of state (EoS), using known ab-initio constraints and astrophysical observations to limit its behavior at intermediate densities. Permitting explicit first-order phase transitions allows us to systematically search for twin-star solutions, i.e. the existence of stars degenerate in mass but differing in radius. We find that current observational constraints exclude all but two classes of twin stars. The first is characterized by a first-order transition occurring at a very low density, where the material properties of the system either stay largely intact or move away from the conformal limit. In the second, more interesting class, the discontinuity in the mass-radius curve emerges after a rapid crossover transition at a significantly higher density, with the speed of sound exhibiting two sharp peaks at distinct densities. Since neither class shows clear conformalization upon entering the second branch, the standard twin-star scenario linking the mass-radius discontinuity to deconfinement can be firmly ruled out, while even the remaining solutions -- disfavored by per-mille Bayes factors and in tension with theoretical bounds -- are likely to be excluded in the future.

    ↳ astro-ph.HEhep-phnucl-thPRD(2026)·9 citations
65. 65*

    Six-loop gravitational interactions at the sixth post-Newtonian order

    Giacomo Brunello🇮🇹 · Manoj K. Mandal🇮🇹 · Pierpaolo Mastrolia🇮🇹 · Raj Patil🇩🇪 · Matteo Pegorin🇮🇹 · Jonathan Ronca🇮🇹 · Sid Smith🇮🇹 · Jan Steinhoff🇩🇪 · William J. Torres Bobadilla🇬🇧

    We compute the gravitational interaction of two coalescing compact objects at sixth post-Newtonian order in the static limit, employing the diagrammatic approach within the effective field theory framework of General Relativity. The calculation requires the evaluation of six-loop Feynman diagrams that are mapped onto two-point integrals with a gauge-theory-like structure, which are computed here for the first time. The resulting seventh-order contribution in Newton's constant is finite in three space dimensions. This result provides the most technically demanding missing ingredient for the determination of the conservative dynamics of the gravitational two-body system at sixth post-Newtonian order.

    ↳ hep-thgr-qchep-ph20 citations
66. 66*

    The tidal gap: causality bound on exotic compact objects with applications in the solar and sub-solar mass range

    Benedetta Russo🇮🇹 · Alfredo Urbano🇮🇹

    In this work, we highlight the existence of a lower limit on the tidal deformability parameter $\Lambda$, determined by the requirement of relativistic causality. Additionally, by considering the upper bound set on compactness, we identify the region within the parameter space of compactness versus tidal deformability, where physically motivated exotic compact objects (ECOs) could potentially reside. Our analysis reveals the presence of a tidal gap between black holes, characterized by vanishing tidal deformability, and physically motivated ECOs. Prompted by this finding, we investigate the possibility that a population of maximally compact exotic objects, described by a linear equation of state (EoS), may simultaneously inhabit the lower mass gap and the sub-solar region, thus qualifying as (primordial) black hole mimickers while distinguishing themselves from the latter by their non-zero tidal deformability. Finally, considering the case of solitonic boson stars as proxies for ECOs described by a linear EoS, we discuss how it is possible to further reduce the lower limit on $\Lambda$, provided that the strong energy condition is violated (but not the dominant energy condition, and therefore causality).

    ↳ gr-qcastro-ph.HEhep-ph3 citations
67. 67*

    Structure Functions for small DIS $x$

    Hrachya M. Babujian🇩🇪 · Angela Foerster🇩🇪 · Michael Karowski🇩🇪

    Structure Functions for small DIS (deep inelastic scattering) $x$ for integrable models are investigated, in particular, for the $O(N)$~$\sigma$-model and $SU(N)$ chiral Gross-Neveu model, which are asymptotically free. We get the universal behavior $x^{-1}{\ln }^{-2}x$ at small Bjorken variable $x$ and confirm a Balog Weisz conjecture. For a the second group of models, the Sine-Gordon, sinh-Gordon and $Z(N)$, we find power behavior $x^{-\lambda }$. The special behavior of the structure function for the Sine-Gordon model is probably crucial for future investigation in 4D QCD.

    ↳ hep-thhep-phJHEP(2026)·0 citations
68. 68*

    Trigonometric continuous-variable gates and hybrid quantum simulations of the sine-Gordon model

    Tommaso Rainaldi🇺🇸 · Victor Ale🇺🇸 · Matt Grau🇺🇸 · Dmitri Kharzeev🇺🇸 · Enrique Rico🇨🇭 · Felix Ringer🇺🇸 · Pubasha Shome🇺🇸 · George Siopsis🇺🇸

    Hybrid qubit-qumode quantum computing platforms provide a natural setting for simulating interacting bosonic quantum field theories. However, existing continuous-variable gate constructions rely predominantly on polynomial functions of canonical quadratures. In this work, we introduce a complementary universality paradigm based on trigonometric continuous-variable gates, which enable a Fourier-like representation of bosonic operators and are particularly well suited for periodic and non-perturbative interactions. We present a deterministic ancilla-based method for implementing unitary and non-unitary trigonometric gates whose arguments are arbitrary Hermitian functions of qumode quadratures. As a concrete application, we develop a hybrid qubit-qumode quantum simulation of the lattice sine-Gordon model. Using these gates, we prepare ground states via quantum imaginary-time evolution, simulate real-time dynamics, compute time-dependent vertex two-point correlation functions, and extract quantum kink profiles under topological boundary conditions. Our results demonstrate that trigonometric continuous-variable gates provide a physically natural framework for simulating interacting field theories on near-term hybrid quantum hardware, while establishing a parallel route to universality beyond polynomial gate constructions. We expect that the trigonometric gates introduced here to find broader applications, including quantum simulations of condensed matter systems, quantum chemistry, and biological models.

    ↳ quant-phhep-lathep-phnucl-thJHEP(2026)·7 citations
69. 69*

    Quark-mass effects in gradient-flow observables through next-to-next-to-leading order in QCD

    Robert V. Harlander🇩🇪 · Robert H. Mason🇩🇪

    We provide results for the vacuum expectation values of the flowed action density, the quark condensate, and the quark kinetic operator in the gradient-flow formalism. We work in $N_{\text{F}}$-flavor QCD, keeping the heaviest quark massive and all others massless. The vacuum expectation values of these operators are calculated numerically through next-to-next-to-leading order QCD, providing important input for the extraction of fundamental QCD parameters from lattice calculations. While the focus is on charm- and bottom-quark mass effects, we provide the results in a form that is independent of the specific quark mass.

    ↳ hep-lathep-phJHEP(2026)·0 citations
70. 70*

    Are Primordial Black Holes Truly Fine-Tuned?

    A.J. Iovino🇦🇪 · A. Riotto🇨🇭

    Single-field inflationary models which generate primordial black holes through the enhancement of the curvature primordial power at small scales are commonly criticized and frequently dismissed because they require a large amount of fine-tuning in the parameters setting the ultra slow-roll phase. However, the standardly adopted definition of fine-tuning has a clear drawback: the more the primordial black hole abundance is small and cosmologically harmless, the larger the parameter space is fine-tuned. A well-defined indicator of fine-tuning should assign large values to scenarios requiring significant parameter adjustment to reproduce the desired primordial black hole abundance, while yielding values of order unity in cases governed by standard sensitivity. Motivated by such arguments, we use the (modified version of) Wilson's naturalness criterion for quantifying the fine-tuning and naturalness and we show that the primordial black hole models are not technically unnatural.

    ↳ astro-ph.COgr-qchep-phJCAP(2026)·10 citations
71. 71*

    One-Loop Renormalization of Anisotropic Two-Scalar Quantum Field Theories

    Dmitry S. Ageev🇷🇺 · Yulia A. Ageeva🇷🇺

    We develop a basis--covariant one--loop renormalization framework for two interacting real scalars in $D=4-ϵ$ with the most general two--derivative Lorentz--violating quadratic form, allowing anisotropic spatial gradients and direction--dependent kinetic mixing, together with general cubic and quartic interactions forming RG complete set of operators at one-loop. In dimensional regularization with minimal subtraction we compute the full set of one--loop UV divergences and obtain closed beta functions for quartic and cubic couplings, masses. The pole coefficients admit a universal spectral representation as angular averages over the direction--dependent eigenvalues and projectors of the UV kinetic matrix; all anisotropy dependence enters through a single universal kernel admitting two--particle phase--space interpretation. We classify fixed points and fixed manifolds and show, in particular, that anisotropy restricts the existence of the coupled Wilson--Fisher--type fixed point. When the cross--gradients are turned on the coefficients in beta functions are governed by six phase--space weights admitting interpretation in terms of encoding ``populations'' and ``coherences'' of the UV normal modes.

    ↳ hep-thcond-mat.str-elhep-phPRD(2026)·3 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.