Thu·May 28, 2026Thursday·May 28, 2026

1. 01*

   Hunting New Animalcula with Flavour Changing Processes

   Andrzej J. Buras🇩🇪

   This year marks the 350th anniversary of the discovery of the first animalcula (little animals) by van Leeuvanhoek in 1676.Flavour physics makes it possible to search for new animalcula at distance scales far shorter than those resolved by van Leeuwenhoek in 1676 and even shorter than those directly accessible at the Large Hadron Collider and the planned colliders in this century. I summarize various strategies for achieving this goal. While precise measurements of a wide variety of observables and their precise theoretical calculations, both within the Standard Model (SM) and beyond it, are indispensable in this context, in my view it is crucial to develop strategies for the search for New Physics (NP) that go beyond the global fits that are very popular today. While effective field theories such as WET and SMEFT are formulated in terms of Wilson coefficients of the relevant operators, with correlations characteristic of the SM and of specific NP scenarios, the most direct tests of the SM and its extensions are, in my opinion, correlations among different observables, like branching ratios of numerous decays, that are characteristic of particular new animalcula at work

   hep-phhep-exhep-latActa Phys.Polon.B(2026)·2 citations
2. 02*

   Multiplicity distributions in DIS for heavy nucleus

   Carlos Contreras🇨🇱 · José Garrido🇨🇱

   We found solutions to the linear but with complicated kernel and non-homogeneous evolution equations for the cross sections of productions of $n$-cut Balitsky-Fadin-Kuraev-Lipatov (BFKL) Pomerons in the final states of high energy DIS on a nucleus, resumming all multiple rescatterings in the leading logarithmic approximation. For the model leading-twist BFKL kernel, we calculate analytical solutions of these equations by developing the homotopy approach. We also calculate the solution in the large $z=\ln \left(x_{01}^2{Q}_s^2(Y,\mathbf{b})\right)$ and large $n\gtrsim ⟨n(z)⟩$ limits, where $x_{01}$ is the dipole size, $Q_s$ the saturation scale and $⟨n(z)⟩$ is the average multiplicity of the produced gluons. Having these cross sections we calculate the multiplicity distributions of the produced gluons and describe how the upcoming Electron-Ion Collider (EIC) can test our theoretical formalism.

   hep-phnucl-thJ.Subatomic Part.Cosmol.(2026)·1 citation
3. 03*

   $CP$ phase structure of QCD from functional renormalization group

   Yuepeng Guan🇨🇳 · Shinya Matsuzaki🇨🇳 · Masatoshi Yamada🇯🇵

   We study the low-energy properties of QCD-like theories in the presence of a $P$-odd and $U(1)$ axial breaking four-fermion operator $\left(\bar{\psi }\psi \right)\left(\bar{\psi }i{\gamma }_5\psi \right)$. We apply the functional renormalization group for a low-energy effective theory involving the $CP$-violating operator. We find that allowing for the running gauge coupling, the $CP$-violating four-fermion interaction becomes relevant in the chirally broken phase. In the presence of a finite quark mass, the RG running of the $\theta$-parameter is shown to be strongly suppressed toward the infrared. The present work clarifies how strong-$CP$ effects generated at UV can non-trivially be transferred to the infrared physics in QCD-like theories.

   hep-phhep-th0 citations
4. 04*

   Matching second-order classical and 1-loop quantum tensor power spectra in de Sitter spacetime

   A. Hauser🇨🇭 · M. Laine🇨🇭

   Large corrections to the inflationary tensor power spectrum have been speculated to emerge either as second-order scalar-induced classical effects, or as 1-loop quantum corrections. These two sources are not independent of each other. Choosing the example of a massless minimally coupled scalar field, we show how the full 1-loop result can be divided into its classical and vacuum parts. Working first in dimensional regularization, we show that the classical part is IR divergent, with IR referring to small comoving momenta that have an influence for a very long time. In the full 1-loop quantum result, these divergences cancel. Introducing then a momentum cutoff that permits for a numerical evaluation of the classical contribution, we show that the IR sensitivity manifests itself as a cubic divergence. We suggest a procedure of "non-perturbative renormalization" for extracting physical information not affected by the divergence. If this can be implemented in realistic systems, it could consolidate numerical studies of inflationary scalar-induced gravitational waves.

   hep-phgr-qc2 citations
5. 05*

   Tensor molecule $J/\psi J/\psi$: A candidate to the resonance $X(6200)$

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   The hadronic tensor molecule $\mathcal{M}=J/\psi J/\psi$ is investigated in the framework of QCD sum rule method. We evaluate its mass and current coupling using the two-point SR approach. Our result $m=(6290\pm 50)\mathrm{MeV}$ for the mass of $\mathcal{M}$ indicates that it can decay to a pair of mesons $J/\psi J/\psi$. Apart from this dominant channel there are subdominant modes of the molecule $\mathcal{M}$ generated due to annihilation of constituent $\overline{c}c$ quarks to pairs of light quarks $\overline{q}q$ and $\overline{s}s$. This mechanism launches processes $\mathcal{M}\to D_{(s)}^{(\ast )+}{D}_{(s)}^{(\ast )-}$, $D{D}_1(2420)$, $D_s{D}_{s1}(2460)$ and $D_{(s)}^{(\ast )0}{\overline{D}}_{(s)}^{(\ast )0}$. The decays of $\mathcal{M}$ are explored by applying technical tools of the three-point sum rule approach which is necessary to estimate strong couplings at $\mathcal{M}$-meson-meson vertices. Comparing the mass $m$ of the molecule $\mathcal{M}$ and its decay width $\Gamma [\mathcal{M}]=(149\pm 21)\mathrm{MeV}$ with available experimental data, we discuss the molecule $\mathcal{M}$ as a possible candidate to the tensor resonance $X(6200)$.

   hep-phhep-exhep-lat0 citations
6. 06*

   Sensitivity Analysis of the Top-Quark Sector

   Fernando Cornet-Gomez🇪🇸 · Víctor Miralles🇪🇸 · Marcos Miralles López🇬🇧 · María Moreno Llácer🇪🇸 · Marcel Vos🇪🇸

   We study the sensitivity of current and future collider observables to top-quark SMEFT operators through a one-operator-at-a-time analysis. Using data from the Tevatron, LEP, and LHC Run~2, as well as projections for the HL-LHC and future lepton colliders, we identify the measurements that provide the strongest individual constraints. This approach clarifies the role of specific observables in the top-quark SMEFT program and highlights the significant improvement in sensitivity expected at future facilities.

   hep-phhep-exEur.Phys.J.Plus(2026)·2 citations
7. 07*

   Neutrinoless double beta decay in a flipped trinification model with left-right symmetry

   D. N. Dinh🇻🇳

   We investigate neutrinoless double beta ($0\nu \beta \beta$) decay within an extended Standard Model framework based on the $SU(3{)}_C\otimes SU(3{)}_L\otimes SU(3{)}_R\otimes U(1{)}_X$ gauge symmetry, commonly referred to as the filliped trinification model. Following a concise overview of the theoretical structure, we derive expressions for the effective Majorana mass and half-life associated with the dominant decay channels. A comprehensive numerical analysis is then carried out, accompanied by a discussion of the phenomenological implications.

   hep-ph0 citations
8. 08*

   A first extraction of gluon TMDs from Higgs data at the LHC

   Simone Anedda🇮🇹 · Valerio Bertone🇫🇷 · Giuseppe Bozzi🇮🇹 · Matteo Cerutti🇫🇷

   We present the first extraction of the unpolarised gluon transverse-momentum-dependent (TMD) parton distribution from Higgs-boson production data at the LHC within the framework of TMD factorisation. The analysis is based on the currently available set of ATLAS and CMS measurements of the Higgs $q_T$ distribution at $\sqrt{s}=8$ and $13$ TeV in the diphoton and four-lepton decay channels, restricted to the small-$q_T$ region where TMD factorisation is applicable. Theoretical predictions are computed up to N${}^3$LL accuracy, with the contribution of the linearly polarised gluon TMD $h_1^{\perp g}$ accounted for. Fiducial selections are consistently incorporated for both two- (diphoton) and four-body (four-lepton) final states. The fit reproduces both the shape and the normalisation of the experimental data, and yields a moderate sensitivity to the nonperturbative content of gluon TMDs. We further assess the convergence of the perturbative expansion and the stability of the extracted distribution under variations of the $q_T$ cut. This analysis provides a baseline for future extractions combining LHC Higgs measurements with other gluon-sensitive processes spanning a broader range of hard scales.

   hep-phhep-exhep-latEPJC(2026)·5 citations
9. 09*

   Using the Pericentre Precession of LAGEOS II to Constrain Quadratically Coupled Ultralight Dark Matter

   Clare Burrage🇬🇧 · Angus Macdonald🇬🇧 · Elisa Todarello🇺🇸

   It has been proposed that feebly interacting ultralight scalars may constitute the dark matter content of the universe. Models describing the interactions of a dark matter scalar with Standard Model fields may feature quadratic interactions at leading order, such that the scalar acquires an effective mass in the neighbourhood of a classical matter distribution. The effect of their introduction is to provide effective shifts in fundamental constants of physics, as well as to mediate scalar fifth forces between test bodies. We here demonstrate how these fifth forces can result in pericentre precession in the orbital motion of satellites around the Earth. We apply this to the measured pericentre precession of the LAGEOS II experiment, constraining the mass, and couplings to the light Standard Model fields, of a quadratically coupled ultra-light dark matter scalar. We observe such an experiment to be effective in constraining parameter space at strong couplings, where existing constraints from satellite and tabletop level experiments break down.

   hep-phastro-ph.CO4 citations
10. 10*

    Dark Matter Interpretation of the Super-Kamiokande Antineutrino Excess in $\mathrm{U}(1{)}_{L_{\mu }-L_{\tau }}$ model

    Motoi Endo🇯🇵 · Yushi Mura🇯🇵 · Tenta Tsuji🇯🇵

    Recent Super-Kamiokande analyses of the diffuse supernova neutrino background, based on data across all SK phases, indicate a mild preference over the zero-DSNB hypothesis at the level of about $2.3\sigma$ with electron-like antineutrino events at $E_{{\bar{\nu }}_e}\simeq 20\mathrm{MeV}$. We investigate whether this excess can be explained by MeV-scale dark matter annihilation into neutrinos in a $\mathrm{U}(1{)}_{L_{\mu }-L_{\tau }}$ model. The dark matter is a Dirac fermion with $m_{\chi }\simeq 22\mathrm{MeV}$ that annihilates via a light $Z^{\prime }$ mediator into ${\nu }_{\mu }{\bar{\nu }}_{\mu }$ and ${\nu }_{\tau }{\bar{\nu }}_{\tau }$, which are partly converted into ${\bar{\nu }}_e$ through flavor oscillations. We find that this scenario simultaneously accounts for the excess and the observed relic abundance via thermal freeze-out. We further discuss the relevant laboratory and cosmological constraints, including neutrino trident production, NA64-$\mu$, Borexino, and the contribution to $\Delta N_{\mathrm{eff}}$.

    hep-phastro-ph.COhep-ex2 citations
11. 11*

    Probing hidden-charm pentaquarks from the $\pi N\to J/\psi N$ reaction

    Samson Clymton🇰🇷 · Sun-Young Ryu🇯🇵 · Jung-Keun Ahn🇰🇷 · Hyun-Chul Kim🇰🇷

    We investigate the dynamical generation of hidden-charm pentaquark resonances in the $\pi N\to J/\psi N$ reaction utilizing an off-shell coupled-channel formalism. Motivated by the absence of pentaquark signals in $J/\psi$ photoproduction, we evaluate rescattering effects with two-body kernel amplitudes constructed from effective Lagrangians that explicitly incorporate $t$-channel meson and $u$-channel baryon exchanges. We demonstrate that the $u$-channel ${\Lambda }_c$ exchange, of which an analogous contribution is absent in the photoproduction kernel, greatly enhances the rescattering contributions through the ${\bar{D}}^{(\ast )}{\Sigma }_c$ intermediate states. Consequently, the ${\bar{D}}^{(\ast )}{\Sigma }_c^{(\ast )}$ channels yield contributions of comparable magnitude to the ${\bar{D}}^{(\ast )}{\Lambda }_c$ channels, directly leading to prominent pentaquark signals. The partial-wave analysis reveals that the $P_{c\bar{c}}(4312)$ and $P_{c\bar{c}}(4457)$ states emerge as clear peak structures with $J^P=1/2^{-}$ and $3/2^{-}$, respectively. In contrast, the $P_{c\bar{c}}(4380)$ and $J^P=5/2^{-}$ states are strongly suppressed because the ${\Lambda }_c$ exchange does not provide the required tensor interactions. The result for the total cross section reaches the microbarn level at the peak positions.

    hep-phhep-ex0 citations
12. 12*

    Topological Diagram Analysis of Charmed Baryon Decays with Vector Mesons

    Yixuan Wu🇨🇳 · Fanrong Xu🇨🇳 · Hai-Yang Cheng🇹🇼

    In this work, we further develop the application of the topological diagram approach (TDA) to charmed baryon weak decays ${\mathcal{B}}_c\to \mathcal{B}V$ with a vector meson in the final state. By incorporating the Korner-Pati-Woo theorem, we show that only five independent sets of TDA parameters are required. Relations among different decay channels arising from isospin, U-spin, and V-spin symmetries are explicitly derived within the TDA framework. Partial wave contributions and form factors associated with different topological diagrams are extracted from global fits to the experimental data. It is found that the form factors $A_2$ and $B_2$ induced from the tensor interaction of the vector mreson with octet baryons are comparable in magnitude to $A_1$ and $B_1$, implying the importance of the tensor coupling in ${\mathcal{B}}_c\to \mathcal{B}V$ decays. Branching fractions for all ${\mathcal{B}}_c\to \mathcal{B}V$ channels are predicted, and most measured modes are found to be in good agreement with current data. More physical observables, including up-down asymmetries, longitudinal polarizations as well as observables in the subsequent decays are also predicted. Our results provide a systematic framework for understanding charmed baryon weak decays with vector mesons and can be further tested with future experiments.

    hep-phhep-exPRD(2026)·0 citations
13. 13*

    Double D meson production in ultraperipheral $pp$, $pPb$ and $PbPb$ collisions

    Ya-Ping Xie🇨🇳 · Victor P. Goncalves🇧🇷

    The production of a $D^{+}{D}^{-}$ pair by photon - photon interactions at the Large Hadron Collider (LHC) is investigated considering ultraperipheral proton - proton ($pp$), proton - lead ($pPb$) and lead - lead ($PbPb$) collisions. Assuming that the scattering amplitude for the $\gamma \gamma \to D^{+}{D}^{-}$ process can be described by the Brodsky - Lepage formalism in the heavy - quark approximation, we derive the associated differential distributions and total cross - sections. In particular, in addition to the rapidity and transverse momentum distributions, usually presented in the literature, we also present predictions for the total transverse momentum and momentum imbalance distributions. Our results indicate that a future experimental analysis of this final state is, in principle, feasible during the high luminosity run of LHC.

    hep-phhep-ex0 citations
14. 14*

    Two-loop QCD corrections to $H\to b+\bar{b}+g$ at higher powers in the dimensional regulator

    Pulak Banerjee🇮🇳 · Chinmoy Dey🇮🇳 · M. C. Kumar🇮🇳 · Vaibhav Pandey🇮🇳 · V. Ravindran🇮🇳

    We compute the two-loop massless QCD corrections to the amplitude of Higgs boson decay to bottom quark pair and a gluon ($H\to b+\bar{b}+g$) in the higher powers of the dimensional regularization parameter $ϵ$. The calculation is performed by projecting the amplitude onto the appropriate Lorentz structures related to the process. We also show the numerical behaviour of the form factors for a few sample phase-space points. These amplitudes are necessary ingredients for computing the three-loop virtual corrections to bottom-quark annihilation to Higgs plus jet production at the hadron collisions.

    hep-ph0 citations
15. 15*

    Generation as Compositeness: A Subconstituent Interpretation of the $B$-Lattice Flavor Hierarchy

    Vernon Barger🇺🇸

    We interpret the $B$-lattice flavor framework as a compositeness hierarchy: all three fermion generations are elementary chiral fields, but third-generation Yukawa couplings are undressed ($Q=0$), while lighter generations acquire their Yukawa couplings through chains of spin-$0$ subconstituents (``hops'') whose depth is counted by the ${\mathbb{Z}}_9$ discrete gauge symmetry. The ${\mathbb{Z}}_9$ charge admits a two-index decomposition $q_9\mapsto (a,b)$ that identifies two hop species ($\alpha$, $\beta$) and organizes all fundamental scales from $v_{\mathrm{EW}}$ to $M_{\mathrm{Pl}}$ on a ``ninths ladder'' $\Lambda \times {ϵ}^{n/9}$. The lattice structure yields the CKM and PMNS mixing parameterizations (with all mixing exponents expressible as charge differences $\Delta Q$ dressed by a universal Fritzsch--Xing phase shift of $\pm 1/9$), a seesaw benchmark $m_3\simeq 51$~meV, the axion mass window $m_a\sim 7$--$12\mu$eV, and the prediction $\tan \beta \simeq 10$--$16$ (from the chain internal factor combined with the DFSZ-II two-Higgs-doublet structure), all from two parameters ($\Lambda$ and $ϵ=14/75$). Generation-dependent Peccei--Quinn charges restore the axion--photon coupling ($C_{a\gamma }\simeq 0.6$--$1.0$) from ``back to invisible'' suppression. An illustrative UV realization in terms of hypercolor-confined scalars communicated to the SM by a gauge-invariant messenger chain is presented as an existence proof.

    hep-phhep-exhep-thAPS Open Science(2026)·3 citations
16. 16*

    Towards the two-loop electroweak corrections to the Drell-Yan process: the complete fermionic contributions

    Tommaso Armadillo🇧🇪 · Simone Devoto🇧🇪 · Michele Dradi🇮🇹 · Alessandro Vicini🇮🇹

    We discuss the production of a lepton pair in quark-antiquark annihilation in the electroweak Standard Model. We present the ultraviolet-renormalised and infrared-subtracted finite contribution of the complete set of second-order virtual corrections with a closed fermionic loop, to the cross section of the process $u\bar{u}\to {\mu }^{+}{\mu }^{-}$. The evaluation of these contributions is based on an automated methodology, whose validity is discussed with explicit tests. These corrections are one of the building blocks necessary for the simulation of the inclusive lepton-pair production cross section at next-to-next-to-leading order in the electroweak interaction.

    hep-phhep-th1 citation
17. 17*

    Nonequilibrium coherent effects at finite chemical potential

    Amelie Claussen🇨🇱 · Sebastián Mendizabal🇨🇱

    We study a nonequilibrium coherent effect generated by a finite chemical potential in a complex scalar field with a conserved $U(1)$ charge. The scalar excitation is treated as a probe coupled to an equilibrium thermal reservoir, so the self-energy is an equilibrium kernel and there is no backreaction on the bath. Solving the Schwinger-Keldysh-Kadanoff-Baym equations in the normal phase, when the chemical potential is smaller than the dispersion relation, we keep the particle and antiparticle quasiparticle poles separate. The source-driven inhomogeneous statistical propagator is fixed by the reservoir and relaxes to the usual decoherent equilibrium form. By contrast, the homogeneous solution carries initial-condition memory; finite chemical potential turns this memory into a transient particle-antiparticle interference pattern by splitting the two charge-sector phases. The effect is not a new equilibrium mode, but a phase-sensitive remnant of the initial data that is erased by damping as $t\to \infty$. We define a normalized interference contrast extracted from the mixed charge-sector terms, illustrate the relaxation using the plasmon damping rate of hot scalar ${\varphi }^4$ theory, and show that the same normal-phase solution displays the infrared enhancement that precedes Bose-Einstein condensation.

    hep-phhep-th0 citations
18. 18*

    Linking the Gauge Hierarchy with Neutrino Masses and Dark Matter via Two-step Cosmological Selection

    Jin-Lei Yang🇨🇳 · Frank F. Deppisch🇬🇧

    The hierarchy problem between the electroweak (EW) and Planck scales remains a central puzzle in modern physics. We discuss a promising solution operating through the cosmological selection of the EW vacuum in a multiverse landscape, where the EW scale is dynamically approached as the configuration that maximizes the vacuum energy. By extending the Standard Model with a complex scalar singlet and right-handed neutrinos, charged under a global $U(1{)}_{B-L}$ symmetry, the model not only explains the smallness of the EW scale. It can also account for neutrino masses via the seesaw mechanism and the matter-antimatter asymmetry via leptogenesis. In addition, it provides a viable dark matter candidate that is testable in future neutrino experiments.

    hep-ph1 citation
19. 19*

    Maximum phase-space density of linearly polarized gluon TMDs in the saturation region

    Lei Wang🇨🇳

    We calculate the Sudakov-limited maximum phase-space density associated with the linearly polarized gluon TMD coefficient $h_1^{\perp g}$ in the saturation region. Using Mueller's occupancy argument together with the small-$x$ Weizsäcker-Williams (WW) and dipole gluon distributions of Metz and Zhou, we find $n_{h,\mathrm{DP}}^{\max }=2n_g^{\max }\sim 2{\alpha }_s^{-3/2}$ for the dipole distribution in the same phase-space normalization. This dipole result is a process-dependent TMD proxy, not a literal gluon number density. For the WW distribution, the deep-saturation tensor coefficient lacks the logarithmic enhancement needed for the Mueller saddle, so the maximum is pushed toward the saturation boundary. We also perform a numerical Collins-Soper evolution study and find that the $J_2$ Bessel weight in the tensor TMD definition reduces the resolved peak, giving $c_h^{\mathrm{num}}\simeq 6.6$--$7.1$ for representative EIC scales.

    hep-ph0 citations
20. 20*

    Critique of Breit-Wigner resonance scattering

    Philip D. Mannheim🇺🇸

    In the standard Breit-Wigner approach to scattering the phase shift is to have a form $\tan {\delta }_{\mathrm{BW}}={\Gamma }_1/(E_1-E)$ at a real energy resonance. This leads to complex energy poles in the scattering amplitude at $E_{\mathrm{BW}}=E_1-i{\Gamma }_1$, poles that are identified with unstable physical particles. By solving the square well scattering problem we identify some challenges to this approach. We find that setting $\tan {\delta }_{\mathrm{BW}}={\Gamma }_1/(E_1-E)$ is not always a good description of the real energy scattering amplitude, that ${\Gamma }_1$ can be negative, that $E_{\mathrm{BW}}$ is not in fact an energy eigenvalue (and thus not a physical particle), and that states that decay in energy possess spatial wave functions that unacceptably grow exponentially. All of this is resolved by noting that because of its antilinear $PT$ symmetry solutions to the square well Schrödinger equation appear in complex conjugate energy pairs $E_{\mp }=E_2\mp i{\Gamma }_2$ with $E_{-}\ne E_{\mathrm{BW}}$, doing so in a way that gives a time independent probability amplitude that neither grows nor decays in time or space, and leads to just one now observable physical resonance not two.

    hep-ph0 citations
21. 21*

    Energy-energy correlators inside single inclusive jets in heavy-ion collisions with CoLBT-hydro model

    Zhong Yang🇺🇸 · Raghav Kunnawalkam Elayavalli🇺🇸 · Xin-Nian Wang🇨🇳

    The energy-energy correlator (EEC) inside jets is a sensitive observable for studying jet modification in the quark-gluon plasma (QGP). However, its interpretation in heavy-ion collisions remains challenging, requiring a consistent understanding of jet evolution across multiple dynamical scales together with a proper treatment of the background subtraction. In this work, we employ an updated CoLBT-hydro framework in which a medium scale $Q_M$ = 2.0 GeV is introduced to separate the vacuum and in-medium stages of the parton shower, enabling a more self-consistent treatment of jet evolution. Using a theoretical background subtraction within the model, the resulting simulation reproduces the recent CMS measurement of the in-jet EEC, and through a decomposition of different contributions, highlights the impact of medium modification on the observable. To further validate the experimental procedure, we also implement the CMS mixed-event background-subtraction method directly in the simulation and find the results are consistent with those obtained with the theoretical background subtraction. Using $p_T$-ranked jets in each event, we further investigate the dependence of medium modification on the in-medium path length, reflected in the different EECs of leading and sub-leading jets. Finally, we explore the dependence of the leading-jet EEC on the dijet rapidity gap as a signal of the jet-induced diffusion wake.

    hep-ph2 citations
22. 22*

    Minimal dark $SU(2)$ origin of a massless Dirac neutrino

    P. S. Bhupal Dev🇺🇸 · Julia Gehrlein🇺🇸 · Amartya Sengupta🇺🇸 · Amarjit Soni🇺🇸

    We propose a gauge-symmetry origin of a rank-two Dirac neutrino mass matrix that enforces one exactly massless neutrino, while being consistent with the oscillation data, as well as cosmological constraints. The mechanism relies on a minimal dark $SU(2{)}_D$ gauge symmetry under which one right-handed-neutrino-like Weyl fermion is charged, thereby forbidding its Standard Model Yukawa coupling. Quantum consistency then fixes the minimal dark-sector completion: Cancellation of the Witten anomaly requires a second fermionic $SU(2{)}_D$ doublet, while a discrete $Z_4$ symmetry that forbids Majorana masses allows the two dark doublets to form a vectorlike pair. This anomaly-free completion gives rise to a secluded, confining dark sector with a viable dark matter candidate, linking the protected neutrino texture to dark infrared dynamics.

    hep-phastro-ph.COPRD(2026)·1 citation
23. 23*

    Bump Hunting Inside Jets with Energy Correlators

    Lorenzo Ricci🇺🇸 · Marc Riembau🇨🇭 · Minho Son🇰🇷

    Energy correlators exhibit well-understood scaling behavior in the collinear limit, governed by perturbative QCD dynamics. We explore how this scaling regime is broken by new physics, converting precise energy correlator measurements into a broadband search for new physics. Under generic assumptions, unitarity and positivity are sufficient to classify and constrain the relevant signatures, which imprint an angular resonance on top of this smoothly scaling background. This converts the search into bump hunting within jets. As a proof of principle, we derive projected LHC sensitivity for a light hadrophilic $Z^{\prime }$, finding competitive constraints with existing searches.

    hep-phhep-ex1 citation
24. 24*

    FunKit: A computer algebra toolkit for functional approaches

    Franz R. Sattler🇩🇪

    We introduce FunKit, a Mathematica package for the derivation and tracing of functional equations from arbitrary master equations. FunKit provides an expression vocabulary and a set of rules that allow for derivations in any given field theory and master equation. It also allows users to add extensions for more specific equation systems. Therefore, it can be used in a wide range of situations, for example Dyson--Schwinger or functional RG equations, flowing reparametrisations, nPI equations, (modified) STIs and WTIs, functional Polchinski and Wegner flows, functional master equations with sources, and many others. Besides interfacing with the \FORM language to trace large tensor expressions efficiently, FunKit also provides facilities to export arbitrary Mathematica expressions to C++, Julia or Fortran code, including the results of derivations, which can then be evaluated numerically. Both the tracing and code generation can also be used independently and in combination with other packages.

    hep-phcond-mat.otherhep-th2 citations
25. 25*

    Neural Scaling Laws for Jet Generation

    Oz Amram🇺🇸 · Darius A. Faroughy🇺🇸 · Tjarko Gerdes🇩🇪 · Anna Hallin🇩🇪 · Gregor Kasieczka🇩🇪 · Michael Krämer🇩🇪 · Humberto Reyes-Gonzalez🇩🇪 · David Shih🇺🇸

    Recently observed empirical scaling laws describe the performance of foundation-type models as three independent key quantities -- dataset size, compute, and model parameters -- are modified. Extracting these scaling laws informs the training of large complex models for which the tuning of hyperparameters in traditional ways is not feasible. This work for the first time explores if scaling laws can also be observed for the task of particle jet generation -- both relevant as a pre-training objective for foundation models and as in-situ simulation by itself. We indeed replicate the key logarithmic scaling law behavior for model-size scaling. Beyond studying the next token prediction validation loss of the generative model, we also study the sliced Wasserstein distance of five physical quantities that are not immediately available to the model during training. Our study shows that this quantity is monotonically related to the next token prediction validation loss, meaning that this loss is indeed a good proxy for the physics performance. For the scaling with dataset size and compute, we observe substantially weaker scaling behavior of both the loss and the sliced Wasserstein distance. We analyze this behavior by introducing the concept of a learnable window, and argue that autoregressive next token prediction on jet constituents exhibits comparatively rapid saturation relative to language-model studies. We discuss possible origins of this behavior, including the stochastic nature of QCD radiation and differences between generative and supervised learning tasks in collider physics.

    hep-phcs.LGhep-exphysics.data-an5 citations
26. 26*

    Heavy Axion from a Confining Mirror GUT

    Giacomo Cacciapaglia🇫🇷 · Csaba Csáki🇺🇸 · Teng Ma🇨🇳

    We propose a new framework for solving the strong CP problem via a heavy axion, using mirror symmetry and grand unification. The mirror GUT sector remains unbroken and dynamically generates a calculable heavy mass scale via confinement without fine tuning. Models in this class feature a heavy axion, whose potential is less sensitive to Planck scale corrections, as well as a rich hidden sector from the confined mirror GUT. The solution to the strong CP problem remains unspoiled by the presence of additional phases in the GUT Yukawas, yet allowing the possibility of electric dipole moments within the reach of future experiments. Our proposal offers new directions in GUT model building, axion phenomenology, dark matter and cosmology.

    hep-phhep-th2 citations
27. 27*

    MATBG Josephson diode as an universal thermal machine

    Hadi Mohammed Soufy · Colin Benjamin

    Magic-angle twisted bilayer graphene Josephson junctions (MATBG-JJ) with a gate-tunable valley-polarized weak link exhibit an intrinsic Josephson diode effect originating from broken symmetries associated with valley polarization and band-structure anisotropy. Exploiting this nonreciprocal superconducting platform, we construct quantum Stirling (QSC), Otto (QOC), and Carnot (QCC) thermodynamic cycles, where the valley-polarization potential ${\Delta }_v$ acts as the principal control parameter, in contrast to conventional Josephson thermal machines driven by superconducting phase bias. We systematically compare the performance of MATBG-based Josephson diode thermal machines (MATBG-JDTM) with MATBG-based Josephson junction thermal machines (MATBG-JJTM) and AA-stacked bilayer graphene Josephson junction thermal machines (AABLG-JJTM). Owing to the flat-band-enhanced density of states and electrically tunable nonreciprocal transport in MATBG, both MATBG-JDTM and MATBG-JJTM exhibit significantly enhanced work output and efficiency over a broad operating regime compared to AABLG-JJTM. In particular, the gate-controlled MATBG-JDTM provides a flux-free alternative to conventional phase-driven architectures, mitigating limitations associated with magnetic-flux control and flux-noise effects. Our results establish MATBG Josephson diode platforms as a promising route toward electrically tunable quantum thermal machines and nonreciprocal superconducting caloritronics.

    ↳ cond-mat.mes-hallhep-phphysics.app-phquant-ph0 citations
28. 28*

    Stationary generalizations for the vacuum ring wormhole

    Mikhail S. Volkov🇫🇷

    The ring wormhole is the zero-mass limit of the Kerr metric. Its geometry is locally flat, but the topology is nontrivial, with a throat connecting two asymptotic regions and a distributional curvature singularity on the ring encircling the throat. We construct stationary generalizations of this static wormhole that are different from Kerr and invariant under reflections across the wormhole throat. The problem reduces to solving the vacuum Ernst equations subject to the corresponding symmetry conditions. The slowly rotating perturbative solutions were constructed previously, while we now present a detailed analysis of non-perturbative solutions obtained within a numerical framework. For slow rotation, they exhibit the non-relativistic relation $M\sim J^2$ between the mass and angular momentum, which transforms into the Regge relation $J=M^2$ in the fast-rotation regime, when $J\to \infty$ and the ring is stretched without bound by the centrifugal force. However, if the ring size in the static limit is sent to zero at the same time, then $M$ and $J$ remain bounded as the throat linear velocity approaches unity. The wormhole geometry then approaches the extremal Kerr solution, thus ``mimicking'' it. The wormholes carry a curvature singularity at the ring, but this can be removed by via simple ``scalarization'' procedure that promotes the vacuum solutions to regular wormholes with a phantom scalar field.

    ↳ gr-qchep-phhep-th0 citations
29. 29*

    Transient axion streams from disrupted miniclusters

    Luca Visinelli🇮🇹 · Momchil Naydenov🇧🇬

    We investigate the formation and evolution of axion streams generated by the tidal disruption of axion miniclusters through stellar encounters in the Milky Way halo. Combining a large-scale Monte Carlo treatment of repeated stellar flybys with a tracer reconstruction of the stripped debris, we follow the phase-space evolution of the streams across a broad range of galactocentric radii and assess their contribution to the local dark matter distribution. We find that the kinetic energy of the stripped debris typically exceeds its residual self-gravitational binding energy at formation, so that the subsequent evolution is dominated by anisotropic free expansion and orbital shear. As a result, stream densities can decrease by factors as large as $\sim 10^{-9}$ over Galactic timescales, strongly suppressing the steady-state abundance of dense streams near the Solar circle. At the Solar radius, only a small fraction of realizations yields a nonzero encounter probability over a 10 year exposure, implying that observable streams are dominated by rare recent and nearby disruption events rather than by a persistent population of long-lived overdense substructure. Despite this rapid dilution, the streams remain dynamically cold and produce detector-frame linewidths many orders of magnitude narrower than the cavity bandwidths of current haloscope experiments. For representative haloscope configurations, we find characteristic stream linewidths in the range $\Delta {\nu }_{\mathrm{stream}}\sim 10^{-7}-10^1\mathrm{Hz}$, while the corresponding Doppler drift remains well below the cavity response width.

    ↳ astro-ph.GAastro-ph.COgr-qchep-ph1 citation
30. 30*

    Fermionic Bubble Loop in Cosmological Collider Revisited: Exact signals from spectral and Mellin-Barnes methods

    Shuntaro Aoki🇯🇵 · Zhehan Qin🇨🇳 · Masahide Yamaguchi🇰🇷 · Yuhang Zhu🇰🇷

    Fermionic degrees of freedom are essential ingredients in cosmological collider physics and are well motivated by many phenomenological models beyond the Standard Model, but their signals remain largely unexplored due to the difficulty of computing loop diagrams. In this work, we ask how fermionic bubble loops contribute to cosmological collider signals and provide an exact answer for arbitrary couplings. We develop two parallel analytical methods whose agreement provides a non-trivial check of the result. The first method is similar in spirit to spectral decomposition and is built directly from an identity for the product of propagators, which turns the bubble signal into an infinite sum of tree-level exchange signals. The second method is based on the Mellin-Barnes representation, where the result is reconstructed from the residues of distinct families of poles. We also show that the fermionic bubble can be generated from the scalar bubble by the action of appropriate differential operators. As a phenomenologically important application, we consider Yukawa interactions between fermions and the inflaton, finding that the resulting bispectrum signal vanishes identically. Through the spectral decomposition, this vanishing can be traced to a field redefinition of the associated tree-level counterparts.

    ↳ hep-thastro-ph.COgr-qchep-ph4 citations
31. 31*

    More about modular symmetries and non-invertible properties in magnetized compactifications

    Tatsuo Kobayashi🇯🇵 · Shuhei Miyamoto🇯🇵 · Riku Nakano🇯🇵 · Ryusei Nishida🇯🇵 · Haruki Uchida🇯🇵

    We study the modular symmetry in magnetized compactifications. The zero-modes with different Scherk-Schwarz phases transform each other. A generic model does not include modes with all the Scherk-Schwarz phases. Incomplete multiplet representations appear. Thus, the modular symmetry is violated as group-like symmetry. However, the modular symmetry still controls coupling terms in those models. Modular forms of the full symmetry appear as coupling constants.

    ↳ hep-thhep-ph0 citations
32. 32*

    The origin of excited states of the $\Lambda$ baryon at the SU(3) point from Lattice QCD

    Javier Suarez Sucunza🇩🇪 · Thomas Luu🇩🇪 · Maxim Mai🇺🇸 · Ferenc Pittler🇨🇾 · Carsten Urbach🇩🇪 · Haobo Yan🇨🇳

    In this work we determine the finite-volume lattice QCD spectrum at the flavor symmetric $\mathrm{SU}(3)$ point in the meson-baryon singlet and octet irreducible representations. We construct the appropriate interpolation operators and perform the calculation on ensembles in quite large volume ($L=48$). We find three below-threshold energy levels, with the singlet having lower energy and the two octets being non-degenerate at one sigma, which for these large volumes ($M_{\pi }L\approx 14.5$) strongly suggests a bound state close to that energy at each of the irreducible representations. We confront this finite-volume spectrum with the prediction from UCHPT through the Lüscher method finding qualitative agreement. Finally we perform a re-fit of UCHPT free parameters to the available (experimental and lattice) data including the energy levels calculated in this work. This allows us to follow the pole trajectories to the physical point, identifying the $\Lambda (1405)$ as a lower octet, and $\Lambda (1380)$ as a singlet bound state in the $\mathrm{SU}(3)$ limit. Furthermore, $\Lambda (1670)$ is identified on a qualitative level as the heavier octet bound state and its relation to three-body final states is discussed.

    ↳ hep-lathep-phnucl-th0 citations
33. 33*

    Isochrone Fitting of Galactic Globular Clusters -- VIII. Homogeneous estimates of parameters for 27 clusters

    G. A. Gontcharov🇷🇺 · O. S. Ryutina🇷🇺 · C. J. Bonatto · S. S. Savchenko · S. V. Troitsky🇷🇺

    We use the Stetson, HST, and Gaia DR3 data sets for 22 Galactic globular clusters to select their members and fit their CMDs with isochrones from DSED and BaSTI for $[\alpha /$Fe$]=+0.4$ and an adopted helium mass fraction $Y$. As a result, we estimate the metallicity [Fe/H], age, distance from the Sun, and reddening E(B-V) for these clusters. Special attention is paid to identify variable stars among the cluster members. We combine these results with our earlier estimates for five other clusters into a homogeneous set of parameters for 27 clusters and investigate relationships among these parameters and their statistical properties. In particular, we count the giants on the red (RGB), horizontal (HB), and asymptotic branches using the clean data sets cross-identified to cover the entire cluster fields and count each giant only ones. This allows us to calculate the $R$-parameter, the ratio between the numbers of the HB and RGB, with unprecedented accuracy and to examine its relations with other parameters. These relations are much stronger for accreted clusters rejecting a constant $R$ value for them, possibly because of their heterogeneous origins and environments. For all in-situ clusters, a constant value of $R=1.31_{-0.05}^{+0.06}$ is consistent with the data. According to previous calculations, this value may imply anomalous energy losses in HB stars corresponding to an axion--photon coupling of $g_{a\gamma }=(0.66_{-0.13}^{+0.11})\times 10^{-10}{\mathrm{GeV}}^{-1}$. However, the observed dependencies of $R$ on cluster parameters require improved statistics and a theoretical understanding of these dependencies. By comparing $R$-parameter estimates from HST and Gaia in cluster centres and peripheries, respectively, we suggest that the peripheral HB population is depleted by about half when the cluster crosses the Galactic disk, then the HB recovers over 60-80 Myr.

    ↳ astro-ph.GAastro-ph.COastro-ph.HEastro-ph.SR+11 citation
34. 34*

    CP-violation or Nuclear Excitation: Reviewing the Role of Neutrino Interaction Model Uncertainties on Accelerator-Based Neutrino Oscillation Measurements

    Stephen Dolan🇨🇭 · Luke Pickering🇬🇧 · Patrick Stowell🇬🇧 · Callum Wilkinson🇺🇸 · Clarence Wret🇬🇧

    Accelerator-based neutrino oscillation experiments have the potential to revolutionise our understanding of fundamental physics, offering an opportunity to characterise charge-parity violation in the lepton sector; to determine the neutrino mass ordering; and to explore the possibility of physics beyond three-flavour neutrino mixing. However, as more data is collected, the current and next-generation of experiments will require increasingly precise control over the systematic uncertainties within their analyses. It is well known that some of the most challenging uncertainties to overcome stem from our uncertain modelling of neutrino--nucleus interactions, which also affect the event rates used to infer the oscillation probability. The sources of these uncertainties are often related to subtle details of the pertinent nuclear physics which are extremely difficult to control with sufficient precision. Confronting such uncertainties requires both state-of-the-art theoretical modelling and precise measurements of neutrino interaction event rates at experiment's near detectors, before oscillations occur. In this work, we review the role of neutrino interaction systematic uncertainties in current and future measurements of neutrino oscillation as well as the experimental and theoretical prospects for reducing them to an acceptable level for the next generation of experiments.

    ↳ hep-exhep-ph8 citations
35. 35*

    Characterising the role of final state interactions on neutrino energy estimation in the DUNE and Hyper-K era

    Stephen Dolan🇨🇭 · Jake McKean🇯🇵 · Laura Munteanu🇨🇭

    The Deep Underground Neutrino Experiment (DUNE) and Hyper-Kamiokande (Hyper-K) will measure neutrino oscillation parameters with an unprecedented precision that requires neutrino energy estimation to be controlled at the few-MeV level. A central challenge in achieving this is the modelling of the reinteractions of hadrons produced in neutrino-nucleus scatters with the residual nuclear medium, or final-state interactions (FSI). In this work we use state-of-the-art neutrino interaction event generators to review the impact of FSI modelling on the kinematic and calorimetric neutrino energy estimators used by Hyper-K and DUNE respectively, considering both the semi-classical intranuclear cascades (INCs) that dominate current simulations and a microscopic treatment based on a relativistic mean field calculation. We find that plausible variations of the FSI model introduce uncertainties on the neutrino energy estimation proxies that are at or above the precision on the energy scale control required for Hyper-K and DUNE projected neutrino oscillation sensitivities, highlighting the importance of careful FSI modelling to allow robust near detector constraints. We further demonstrate that the two experiments are sensitive to different aspects of the FSI models. Neutrino energy estimation at Hyper-K is most impacted by pion absorption and nuclear effects beyond the semi-classical paradigm, whilst the DUNE energy estimation is more affected by the modelling of how hadronic energy is shared between sources of visible and invisible energy in the detector. We discuss the implications of these findings for neutrino oscillation analyses and outline some of the key experimental and theoretical developments needed to bring FSI modelling uncertainties under control.

    ↳ hep-exhep-ph3 citations
36. 36*

    Whispers of Supergravity in Gravitational Wave Backgrounds: Determining the Gravitino Mass from Cosmic Thermal History

    Angus Spalding🇬🇧 · Stephen F. King🇬🇧

    Gravitino masses above the electroweak scale provide the simplest solution to the gravitino problem, but such large mass scales lie far beyond the reach of collider experiments. We show that the stochastic gravitational wave background offers a direct probe of this otherwise inaccessible regime. Despite decaying before Big-Bang Nucleosynthesis (BBN), these gravitinos naturally generate a period of early matter domination in the early universe. This non-standard epoch leaves a characteristic imprint on any primordial gravitational wave background, characterised by two frequencies corresponding to the onset and end of this phase. We demonstrate that these features can be used to directly infer both the gravitino mass and its initial abundance in a direct mapping. Future gravitational wave observatories span a vast frequency range, enabling sensitivity to gravitino masses from the BBN bound of $\mathcal{O}(100)\text{TeV}$ all the way up to $\mathcal{O}(10^{10})\text{TeV}$, with recent signal by NANOGrav already probing masses in the range $500$-$10^4$ TeV. Gravitational wave observables therefore probe an enormous region of parameter space, far beyond the reach of collider experiments. We are entering an era in which supergravity can be probed through gravitational wave backgrounds alongside collider experiments.

    ↳ astro-ph.COhep-ph0 citations
37. 37*

    Quantum effects in the quadrupole rotor picture of ultra-relativistic ion-ion collisions

    Stavros Bofos🇫🇷 · Yi Li🇨🇳 · Chenrong Ding🇨🇳 · Benjamin Bally🇩🇪 · Thomas Duguet🇫🇷 · Mikael Frosini🇫🇷 · Jiangming Yao🇨🇳

    The azimuthal hadronic flow observed in ultra-relativistic ion-ion collisions provides a sensitive probe of many-body ground-state correlations in the colliding nuclei. In particular, collective correlations associated with nuclear "intrinsic deformation" are expected to leave pronounced fingerprints on specific final-state observables. However, such effects are commonly interpreted within a classical rigid-rotor picture, despite the intrinsically quantum nature of nuclei. In this Letter, the validity of this interpretation is assessed systematically across the nuclear chart by comparing the quantum quadrupole rotor with its classical rigid-rotor limit. Quantum contributions associated with the fermionic nature of the nucleons are shown to be largely independent of shell effects, and hence of the intrinsic deformation. While they account for nearly all of the quantum rotor effective quadrupole deformation in light and/or spherical nuclei, they drop below 10% in intrinsically well deformed heavy nuclei. The present letter demonstrates that a quantitative interpretation of nuclear-structure effects in final-state observables requires going beyond the classical rigid-rotor paradigm. Beyond the quantum contributions quantified presently, correlations associated with collective vibrations and with the non-collective nucleonic motion must be further included and characterized.

    ↳ nucl-thhep-phnucl-ex7 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.