Mon·Mar 2, 2026Monday·March 2, 2026

1. 01*

   Hadronic Contributions to the Muon $g-2$ in Improved Holographic QCD Models

   Jin-Yang Shen🇨🇳 · Wen-Yuan Peng🇨🇳 · Ling-Yun Dai🇨🇳 · Zhen Fang🇨🇳

   We present a systematic study of the hadronic contributions to the muon anomalous magnetic moment within several infrared-improved AdS/QCD models. The models are constrained by the pion decay constant and the $\rho$-meson mass and are shown to reproduce phenomenologically reasonable low-energy hadron spectra. Within a unified holographic framework, we evaluate both the leading-order hadronic vacuum polarization contribution and the pseudoscalar-pole contribution to hadronic light-by-light scattering. The holographic predictions for the hadronic vacuum polarization contribution are found to be systematically lower than recent dispersive determinations, and we demonstrate that this discrepancy is closely correlated with an underestimation of the $\rho$-meson decay constant in the models. We further compute the pion transition form factor and the corresponding pseudoscalar-pole hadronic light-by-light contribution. Although the models yield similar pion mass spectra and reproduce the expected asymptotic behavior, their predictions for the hadronic light-by-light contribution exhibit sizable variations, driven by differences in the transition form factor in the low momentum transfer $Q^2$ region.

   hep-ph2 citations
2. 02*

   Correlation-Induced Interferometric Geometric Phase Difference in Entangled Neutral Meson Systems

   Swarup Sangiri🇮🇳

   We investigate the phase structure associated with correlated evolution in entangled neutral meson systems. Working within a rephasing-invariant interferometric framework, we construct the time-dependent interferometric geometric phase associated with the antisymmetric entangled neutral meson state undergoing nonunitary evolution. Exploiting the natural factorization of the overlap amplitude into global propagation and interference contributions, we derive an explicit expression for the phase in terms of the mass and decay-width differences that govern neutral meson mixing. To place the entangled phase in context, we derive the corresponding interferometric geometric phases accumulated by independently evolving neutral mesons within the same framework. This comparison naturally leads to the introduction of a correlation-induced interferometric geometric phase difference, $\Delta \gamma ={\gamma }_{\mathrm{g}}^{\mathrm{ent}}-{\gamma }_{\mathrm{g}}^{(1)}-{\gamma }_{\mathrm{g}}^{(2)}$, defined as the deviation of the entangled interferometric geometric phase from the sum of the associated single-meson phases. We show that this quantity characterizes the nonadditive phase structure generated by correlated meson evolution and originates from interference between propagation pathways that have no analogue in isolated meson dynamics. The resulting phases depend solely on the eigenvalue differences governing neutral meson oscillations and decay. The system-dependent behavior of the interferometric geometric phases and the correlation-induced phase difference is analyzed across different neutral meson families, illustrating how the underlying mixing dynamics shape the resulting phase correlations. Our results provide an interferometric characterization of entangled neutral meson evolution and highlight the role of entanglement in generating nonadditive phase structures associated with correlated meson dynamics.

   hep-ph1 citation
3. 03*

   Very Heavy and Composite Dark Matter: Theory and Experimental Searches

   Joseph Bramante🇨🇦

   Dark matter much heavier than the weak scale remains a comparatively unexplored frontier. This review surveys theoretical and experimental developments on very heavy dark matter, including composite and dissipative formation mechanisms, multiscatter detection, and astrophysical searches.

   hep-ph6 citations
4. 04*

   Annihilation of Secluded Dark Matter into W+W- Enhanced by P-wave Sommerfeld Effect

   Nobuki Yoshimatsu🇯🇵

   We propose that a pair of annihilation of the secluded dark matter may accommodate a source of the halo gamma ray signal reported recently, through the p-wave Sommerfeld enhancement. We show that given a weakly coupling of the dark sector to the Higgs bosons, the dark matter annihilation into W+W-, even though induced at 1-loop level, is desirably amplified. We also argue that the supersymmetric framework may readily embody such a model within rather minimal contents.

   hep-ph3 citations
5. 05*

   Spin effects in the tau-lepton pair induced by anomalous magnetic and electric dipole moments

   A.Yu. Korchin🇺🇦

   The possible anomalous New Physics contributions to magnetic and electric dipole moments of the $\tau$ lepton have brought renewed interest in studying $\tau$-pair production at energies of the LHC and future colliders. We discuss effects of electromagnetic and weak dipole moment contributions to the $\tau$-lepton polarization and $\tau \tau$ spin correlations in the $\gamma \gamma \to {\tau }^{-}{\tau }^{+}$ and $q\bar{q}\to {\tau }^{-}{\tau }^{+}$ processes. Such processes have been observed in $pp$ and PbPb collisions in the LHC experiments. Extensions of the Standard Model amplitudes for $\gamma \gamma \to {\tau }^{-}{\tau }^{+}$ and $q\bar{q}\to {\tau }^{-}{\tau }^{+}$ processes, which include dipole moments of the $\tau$ lepton, are implemented in the TauSpinner Monte Carlo program. A few examples of signatures of $\tau \tau$ spin correlations and $\tau$-lepton dipole moments in observables are presented.

   hep-phActa Phys.Polon.Supp.(2026)·0 citations
6. 06*

   Impact of non-standard neutrino-electron interactions on Big Bang Nucleosynthesis

   Julien Froustey🇪🇸 · Stefano Gariazzo🇪🇸 · Jaume Moncho🇪🇸 · Sergio Pastor🇪🇸 · Ofelia Pisanti🇮🇹

   Neutrino non-standard interactions (NSI) with electrons, predicted in many extended theoretical models of particle physics, are known to alter the picture of neutrino decoupling from the cosmic plasma. We update previous analyses of neutrino decoupling in the presence of NSI with electrons, extending the parameter space in order to provide, for the first time, a full study of their effect on the production of light elements during Big Bang Nucleosynthesis (BBN). We compare the BBN bounds on non-universal and flavour-changing NSI parameters with the constraints from terrestrial experiments. Our results show that the limits from BBN are significantly less stringent than the experimental bounds, but they are complementary and can provide a test of neutrino physics at different temperature scales and epochs.

   hep-phastro-ph.CO0 citations
7. 07*

   Probing the Dark Matter EFT with QUEST-DMC: Projected Sensitivities and Attenuation Ceilings

   QUEST-DMC Collaboration: N. Darvishi🇬🇧 · S. Autti🇬🇧 · L. Bloomfield🇬🇧 · A. Casey🇬🇧 · N. Eng🇬🇧 · P. Franchini🇬🇧 · R. P. Haley🇬🇧 · P. J. Heikkinen🇬🇧 · A. Jennings🇯🇵 · A. Kemp🇬🇧 · E. Leason🇬🇧 · J. March-Russell🇬🇧 and 17 other authors

   This proceedings contribution summarises projected constraints from the QUEST-DMC concept, a surface-based direct-detection experiment using superfluid ${}^3$He operated below the millikelvin regime and instrumented with nanomechanical resonators read out by SQUIDs. The low recoil-energy threshold (down to sub-eV for the SQUID configuration) enables sensitivity to sub-GeV dark matter across a wide set of interaction structures beyond the canonical spin-independent and spin-dependent limits. We present projections in the non-relativistic Effective Field Theory (EFT) framework, scanning the standard set of fourteen Galilean-invariant operators and expressing reach in terms of effective dark matter-nucleon (or dark matter-neutron) cross sections. Because QUEST-DMC operates at the surface, we also account for suppression of the incident flux due to scattering in the atmosphere and Earth, which produces an interaction-dependent sensitivity ceiling at large couplings. Finally, we outline how the non-relativistic results map onto representative relativistic EFT dark matter-nucleon bilinears, enabling a compact interpretation of the projected reach in terms of UV-motivated coupling structures.

   hep-phPoS(2026)·0 citations
8. 08*

   Parton distribution functions and theory parameters: an NNPDF perspective

   Richard D. Ball🇬🇧 · Tommaso Giani🇩🇪 · Felix Hekhorn🇫🇮 · Jaco ter Hoeve🇬🇧 · Tanjona R. Rabemananjara🇳🇱 · Juan Rojo🇳🇱 · Roy Stegeman🇬🇧 · Maria Ubiali🇬🇧

   Parton Distribution Functions (PDFs) are a key ingredient in theoretical predictions for Large Hadron Collider (LHC) observables and play a central role in the extraction of precision Standard Model (SM) and Beyond the SM (BSM) parameters from LHC data. Recent analyses demonstrate that the determination of fundamental SM parameters such as ${\alpha }_s(m_Z)$, $m_W$, $m_t$, and ${\sin }^2{\theta }_W$ is strongly influenced by the choice of input PDFs. In this contribution, we present the status and challenges of PDF determination from the NNPDF perspective, both in stand-alone fits and in joint extractions with (B)SM parameters. We place particular emphasis on results for ${\alpha }_s(m_Z)$, $m_t$, and Wilson coefficients in the SM Effective Field Theory (SMEFT) framework.

   hep-ph0 citations
9. 09*

   A Model for Dark Moments of the W Boson

   Thomas G. Rizzo🇺🇸

   Loops of portal matter (PM) fields carrying both dark and Standard Model (SM) quantum numbers can lead to the kinetic mixing (KM) of the SM photon and the analogous dark photon (DP) of a phenomenologically interesting magnitude. However, in specific frameworks, different loops of these same PM fields can also lead to other new types of interactions between some of the SM fields and the DP via the generation of `dark moment'-like couplings, even though the SM fields carry a zero dark charge at tree-level. In recent work, this possibility has been explored for the case when these SM fields are fermionic. In this paper, we extend this idea to the case of the SM $W$ boson employing a previously examined model wherein PM consists of a complex scalar triplet plus a complex singlet, both of which obtain vevs and thus also generate the DP mass. While this setup results in a somewhat stronger interaction between the DP and the $W$ than in the familiar KM setup, the rate for $W+$DP production at the LHC is shown to still be rather small and is very difficult to observe due to large SM backgrounds. The direct production of the scalar PM itself, however, is shown to lead to similar new physics signatures but with much larger rates and are considered here in their own right. The properties of such new PM states may already be constrained by LHC searches in both the $W^{\pm }+$MET and $W^{+}{W}^{-}+$MET channels.

   hep-phPRD(2026)·1 citation
10. 10*

    Kaons in hot and dense QCD

    K. Azizi🇮🇷 · G. Bozkır🇹🇷 · N. Er🇹🇷 · A. Türkan🇺🇸

    We present a systematic QCD sum-rule analysis of the in-medium properties of the charged kaon doublet $K^{\pm }$ over the full $(T,\rho )$ plane relevant to current and forthcoming heavy-ion experiments. Working within the QCD sum-rule framework and incorporating temperature-and density-dependent quark, gluon, and mixed condensates, we derive Borel-transformed sum rules for the effective masses $m_{K^{\pm }}$, the pseudoscalar decay constants $f_{K^{\pm }}$, and the vector self-energy ${\Sigma }_v$ of both charged states simultaneously. Our vacuum results, $m_{K^{-}}=494.6_{-6.9}^{+4.9}$~MeV and $f_{K^{-}}=157.3_{-2.9}^{+4.1}$~MeV (with near-degenerate $K^{+}$ values), are in excellent agreement with Particle Data Group values at the sub-percent level. In the medium, $m_{K^{\pm }}$ decreases monotonically with increasing baryon density and temperature, signalling progressive partial restoration of chiral symmetry. A pronounced mass splitting $\Delta m=m_{K^{-}}-m_{K^{+}}$ develops in baryonic matter, driven by the opposite sign of the Weinberg--Tomozawa vector interaction for the two charge states; it reaches $|\Delta m|\sim 0.35$~GeV near $\rho \simeq 3.2{\rho }_{\mathrm{sat}}$ at $T=0$ and is partially quenched by thermal fluctuations. A central outcome of this study is the extraction of the critical onset density ${\rho }_c$, defined as the threshold beyond which the in-medium modifications of $K^{-}$ properties signal the onset of the transition toward the chirally restored phase. We stress that ${\rho }_c(T)$ should not be interpreted as a precise determination of the QCD critical point-a task beyond the reach of any current effective framework-but rather as an indicator ....

    hep-phhep-exhep-latPRD(2026)·1 citation
11. 11*

    Pion and $\rho$ meson's unpolarized quark distribution functions from $q\bar{q}$ and all Fock-states within Dyson--Schwinger equations

    Chao Shi🇨🇳 · Liming Lu🇨🇳 · Wenbao Jia🇨🇳

    We compute the twist-2 unpolarized quark parton distribution functions (PDFs) of the pion and the $\rho$ meson within the Dyson-Schwinger equations (DSEs) framework using the rainbow-ladder (RL) truncation. A new DSE for the spin-1 hadron's quark-quark correlation matrix is derived, from which the PDFs can be extracted. For the $\rho$ meson, we obtain for the first time within RL-DSEs the unpolarized PDFs corresponding to different helicity states. A pronounced difference is observed between the $|\Lambda |=1$ and $\Lambda =0$ cases, where $\Lambda$ denotes the meson helicity, leading to a nonvanishing and numerically sizable tensor-polarized PDF $f_{1LL}(x)$. We further compare these results with those obtained under a leading Fock-state ($|q\bar{q}⟩$) truncation and find substantial deviations. This comparison demonstrates that the present RL-DSEs framework incorporates higher Fock-state contributions associated with gluonic degrees of freedom, which has a significant impact on the quark distributions.

    hep-ph3 citations
12. 12*

    Two-zero textures of the Majorana neutrino mass matrix from ${\mathbb{Z}}_3$ gauging of ${\mathbb{Z}}_N$ non-invertible symmetry

    Bu-Yao Qu🇨🇳 · Zheng Jiang🇨🇳 · Gui-Jun Ding🇨🇳

    Texture-zero ansatze offer an economical description of neutrino masses, with current data allowing only seven inequivalent two-zero Majorana textures in the charged-lepton mass basis. We investigate how such textures can arise from non-invertible symmetries realized through ${\mathbb{Z}}_3$ gauging of ${\mathbb{Z}}_N$. In contrast to ${\mathbb{Z}}_2$ gauging, which necessarily induces diagonal neutrino mass terms via the Weinberg operator, ${\mathbb{Z}}_3$ gauging admits complex representations and allows a richer class of neutrino mass textures. If the light neutrino mass is described by the Weinberg operator, we find that the textures ${\mathbf{A}}_{1,2}$, ${\mathbf{B}}_{3,4}$, and $\mathbf{C}$ can be realized from the ${\mathbb{Z}}_3$ gauging of ${\mathbb{Z}}_{13}$ symmetry, while all the seven phenomenologically viable two-zero textures can emerge from ${\mathbb{Z}}_3$ gauging of ${\mathbb{Z}}_{19}$ symmetry without requiring supersymmetry. When the neutrino mass is generated by the type-I seesaw mechanism, the structure of the non-invertible symmetry is more restrictive, yielding only texture $\mathbf{C}$ for $N\ne 7$. These results demonstrate the strong predictive power of non-invertible symmetries for neutrino mass textures. Furthermore, the more general ${\mathbb{Z}}_n$ gauging of the ${\mathbb{Z}}_N$ symmetry with $n>3$ is analyzed, which results in novel fusion rules.

    hep-phJHEP(2026)·9 citations
13. 13*

    Fermion Mass Hierarchy and a High Quality Axion From Gauged U(1) Flavor Symmetry

    K.S. Babu🇺🇸 · Sai Charan Chandrasekar🇺🇸 · Zurab Tavartkiladze🇬🇪

    We present a class of models based on a gauged $U(1{)}_F$ flavor symmetry that explains the hierarchical structure of fermion masses and mixings via the Froggatt-Nielsen (FN) mechanism, while also solving the strong CP problem by the Peccei-Quinn (PQ) mechanism. A global $U(1{)}_{\mathrm{PQ}}$ symmetry with a nonzero QCD anomaly emerges accidentally in this setup as a byproduct of the gauged $U(1{)}_F$ symmetry. The resulting axion is shown to be of high quality, with the axion potential safeguarded against quantum gravity corrections by the gauge symmetry. Three models, which are generalizations of the Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion model, are presented realizing this idea. The right-handed neutrino mass scale is identified as the Froggatt-Nielsen scale in these models. We present explicit UV completions of the FN sectors of these models and show that they preserve the high quality of the axion. In these models, the axion acts as a flavon field, leading to testable predictions in flavor-changing decays of neutral mesons. The axion also serves as the dark matter of the universe with the right amount of relic abundance without causing cosmological domain wall problems. Baryon asymmetry of the universe is realized via leptogenesis which is calculable in these models and found to be of the right order of magnitude.

    hep-phastro-ph.COhep-th8 citations
14. 14*

    NNLOCAL: Fully Local Subtractions for Precision Predictions in Hadron Collisions

    Vittorio Del Duca🇮🇹 · Claude Duhr🇩🇪 · Levente Fekésházy🇩🇪 · Flavio Guadagni🇨🇭 · Pooja Mukherjee🇩🇪 · Gábor Somogyi🇭🇺 · Francesco Tramontano🇮🇹 · Sam Van Thurenhout🇭🇺

    This work extends the CoLoRFulNNLO subtraction method to address soft and collinear divergences in the computation of higher-order corrections for hadronic collisions. By utilizing universal local counterterms which can be integrated analytically over the unresolved phase space, we achieve numerically stable, fully-differential predictions. Our publicly available NNLOCAL code serves as a proof-of-concept implementation, validated by calculating the NNLO cross-section for Higgs boson production in gluon-gluon fusion with no light quarks.

    hep-ph1 citation
15. 15*

    Unfolding without Iterations, Adversaries, or Surrogates

    Ayodele Ore🇩🇪 · Tilman Plehn🇩🇪

    Correcting measurements for detector effects and constructing appropriate public data representations is a pressing problem in LHC physics. Current methods solve this inverse problem by relying on iterations, minimax optimization, or a surrogate forward mapping. We introduce Adversary-free Unfolding SanS Iteration or Emulation (AUSSIE), which dispenses with these mechanisms while remaining asymptotically correct. AUSSIE replaces the second OmniFold step with a new loss function that directly yields solutions with minimal dependence on the reference simulation. We showcase AUSSIE on various unfolding tasks, including full-phase-space jet substructure.

    hep-phhep-exphysics.data-anSciPost Phys.(2026)·6 citations
16. 16*

    Putting the Brakes on Axion Strings: Friction and Its Impact on the QCD Axion Abundance

    Anson Hook🇺🇸 · Rajrupa Mondal🇺🇸 · Shourya Mukherjee🇺🇸

    A compelling production mechanism for QCD axion dark matter is from the scaling dynamics of early universe axion strings. We show that in DFSZ-like models containing tree-level interactions between fermions and the axion, friction between the thermal bath and the axion string drastically changes the behavior of the axion string network for lower $f_a$ values. Friction delays the onset of scaling and increases the energy density of axions. Once the effects of friction are included, we argue that in addition to the standard value of $m_a\sim$ meV, $m_a\sim 0.1$ eV also reproduces the dark matter energy density.

    hep-ph4 citations
17. 17*

    An EFT approach to Color decoherence in jet quenching

    Varun Vaidya🇺🇸

    We use the EFT developed in \cite{Mehtar-Tani:2025xxd}, to understand the interference driven phenomenon of color decoherence in inclusive jet production in a dense nuclear medium such as Nuclei or Quark Gluon Plasma. Using the factorization formula in \cite{Mehtar-Tani:2024smp,Mehtar-Tani:2025xxd}, expressed as a series of multi-sub-jet operators, we define and calculate the contribution of the two sub-jet effective operator. This explicitly reveals the emergent angular scale ${\theta }_c$ that controls color decoherence as well an intricate renormalization group structure for the factorized functions. We show that for a jet of radius R in a medium of size L characterized by a jet quenching parameter $\hat{q}$, both the LPM effect and color decoherence are controlled by a single dimensionless parameter $\sqrt{\hat{q}L}LR$ and therefore are equally important for phenomenology. This paper shows how interference driven emergent effects can be included in a factorized framework for computing jet observables in heavy ion collisions.

    hep-phnucl-exnucl-th7 citations
18. 18*

    Finite-temperature Sp(4) Yang-Mills theory: towards the continuum

    Fabian Zierler🇬🇧 · Ed Bennett🇬🇧 · Biagio Lucini🇬🇧 · David Mason🇩🇪 · Maurizio Piai🇬🇧 · Enrico Rinaldi🇯🇵 · Davide Vadacchino🇬🇧

    We present numerical results obtained in a finite-temperature study of the Sp(4) Yang-Mills theory on the lattice. We study its first-order confinement/deconfinement phase transition, by reconstructing the density of states via the Logarithmic Linear Relaxation (LLR) algorithm. We perform our measurements on lattices with different extents of space and time (and aspect ratios). We estimate the size of discretisation and finite-volume artefacts. We find clear signatures of a first-order transition. We determine the critical coupling, the specific heat, and the surface tension, for finite extents of the thermal circle, and use the results to set bounds for the continuum theory.

    ↳ hep-lathep-phPoS(2026)·2 citations
19. 19*

    $S$ factor of ${}^{13}$C($\alpha$,$n$)${}^{16}$O at low energies in cluster effective field theory

    Shung-Ichi Ando🇰🇷

    The ${}^{13}$C($\alpha$,$n$)${}^{16}$O reaction at low energies is studied by constructing an effective field theory. We choose a separation scale at $E=1$~MeV, where $E$ is the initial $\alpha$-${}^{13}$C energy in center-of-mass frame, just below the sharp resonant $5/2^{+}$ state of ${}^{17}$O, and include two open channels, $\alpha$-${}^{13}$C and $n$-${}^{16}$O, and resonant $1/2^{+}$, $5/2^{-}$, $3/2^{+}$ states of ${}^{17}$O in the study. Parameters of the theory are fitted to experimental data, $S$ factor of ${}^{13}$C($\alpha$,$n$)${}^{16}$O at the energies below $E=1$~MeV, including the data sets recently reported by the LUNA and JUNA collaborations, and the $S$ factor of ${}^{13}$C($\alpha$,$n$)${}^{16}$O is extrapolated to the Gamow peak energy $E_G=0.19$~MeV in the low mass AGB stars. We discuss an uncertainty in the estimate of the $S$ factor and confirm that the main part of the uncertainty emerges from the parameter fit of the near-breakup threshold $1/2^{+}$ state of ${}^{17}$O.

    ↳ nucl-thhep-phnucl-ex1 citation
20. 20*

    Dark Acoustic Oscillations and the Hubble Tension

    Mathias Garny🇩🇪 · Florian Niedermann🇸🇪 · Martin S. Sloth🇩🇰

    The Hubble tension and the recently reported anomaly in data from the Dark Energy Spectroscopic Instrument (DESI) are considered to pose serious challenges to the standard $\Lambda$CDM model of cosmology. In this work, we show that resolving the Hubble tension with a scenario featuring dark radiation-matter decoupling (DRMD) predicts the presence of dark acoustic oscillations (DAO) similar in scale to baryon acoustic oscillations (BAO). Using an inference independent of large-scale structure data, relying only on Planck measurements of the cosmic microwave background and SH$0$ES-calibrated supernova data, we find evidence for a DAO signal with drag-horizon scale $r_{d,\mathrm{DAO}}\in [54,65]\mathrm{Mpc}/h$ ($68\%C.I.$) and amplitude $A_{\mathrm{DAO}}\in [0.02,0.05]$ ($68\%C.I.$). These predictions provide a concrete target for current and upcoming large-scale structure surveys, including DESI, Euclid, and the Roman Space Telescope. Remarkably, the predicted DAO properties are consistent with those required to explain the DESI anomaly, offering both an alternative to evolving dark energy and a preliminary validation of the relevance of a dark radiation-matter decoupling scenario for addressing the Hubble tension.

    ↳ astro-ph.COhep-ph6 citations
21. 21*

    A Unified Origin of Primordial Black Hole Dark Matter and Nanohertz Gravitational Waves

    Guillem Domènech🇩🇪 · Shi Pi🇨🇳 · Ao Wang🇨🇳

    Recent high-cadence observations by Subaru-HSC have identified a population of ultrashort-timescale microlensing events, providing a compelling window for planet-mass primordial black holes (PBHs) to constitute the entirety of dark matter. In this Letter, we demonstrate that this PBH population and the nanohertz stochastic gravitational-wave (GW) background reported by pulsar timing arrays (PTAs) can be naturally unified by a single primordial origin: a broad, nearly-flat enhancement of the curvature power spectrum with an amplitude of $O(10^{-2})$. The resulting PBH mass function spans the planet-to-solar mass range, while remaining consistent with all current observational constraints. This unified PBH--induced-GW framework makes concrete multi-messenger predictions, which can be decisively scrutinized by forthcoming microlensing surveys, next-generation PTAs, space-borne interferometers, precision astrometry, and laser ranging experiments.

    ↳ astro-ph.COgr-qchep-phhep-th10 citations
22. 22*

    Imprints of $U_A(1)$ chiral anomaly and disorder in the Dirac eigenspectrum of QCD at finite temperature

    Ravi Shanker🇮🇳 · Harshit Pandey🇮🇳 · Sayantan Sharma🇮🇳

    We perform a comprehensive study of the properties of Dirac eigenvalue spectrum in QCD as a function of temperature on the lattice. In addition to effects due to interplay between interactions and disorder inherently present in a many-body system, the Dirac spectrum also contains crucial information about the effective restoration of different subgroups of almost exact two-flavor chiral symmetry in QCD. We calculate the infrared eigenvalues of the overlap Dirac operator on 2+1 flavor QCD ensembles generated using domain wall fermion discretization, on a large volume lattice. From the normalized level spacing ratios, we identify those eigenvalues that have intermediate level statistics, distinctly different from the majority in the bulk spectrum that follow universal level fluctuations similar to a random matrix of Gaussian unitary type. We provide an explanation of these intermediate level ratios in terms of a specific random matrix model and quantify the correlation between these eigenstates and disorder in the gauge fields manifested in the renormalized Polyakov loop values. Whereas the existence of intermediate eigenmodes is intimately connected to the effective restoration of different subgroups of chiral symmetry close to chiral crossover transition, their origin can be traced to random uncorrelated disorder at higher temperatures when the $U_A(1)$ is effectively restored. We also, for the first time, calculate the Thouless conductance for the Dirac spectrum that quantifies the structural rigidity of the eigenvectors, and use it as a diagnostic tool to understand the restoration of the anomalous $U_A(1)$ subgroup of chiral symmetry and localization driven by disorder.

    ↳ hep-latcond-mat.str-elhep-phhep-thPRD(2026)·2 citations
23. 23*

    Infrared Dressing and the Strong CP Problem: Geometric Renormalization of the Vacuum Angle

    Jorge Gamboa🇨🇱 · Natalia Tapia-Arellano🇺🇸

    We revisit the strong CP problem from the viewpoint of the infrared structure of non-Abelian gauge theories. In Yang-Mills theory, motion between topologically inequivalent vacua may be described in terms of a compact collective coordinate associated with the Chern-Simons number. Implementing an adiabatic separation between slow topological modes and fast gluonic fluctuations leads to a reduced Born-Oppenheimer Hamiltonian governing the infrared dynamics. We show that the physical parameter entering this reduced Hamiltonian is not the bare vacuum angle $\theta$, but an effective holonomy ${\theta }_{\mathrm{eff}}$ that includes a Berry phase induced by the fast gluonic sector. The induced holonomy becomes a self-consistent response function of the infrared dressing, leading to a nonperturbative renormalization group flow for ${\theta }_{\mathrm{eff}}$. This infrared flow admits CP-invariant fixed points toward which the effective vacuum angle is dynamically driven in the infrared limit. In this framework, CP violation is not forbidden by the fundamental theory but becomes dynamically suppressed along the infrared flow generated by adiabatic dressing. The strong CP problem is thus realized as a nonperturbative infrared relaxation mechanism governed by the Berry response of the fast gluonic sector, without the introduction of additional dynamical fields.

    ↳ hep-thhep-ph1 citation

* 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.