HEP Phenomenology·hep-ph

Mon·Aug 3, 2026Monday·August 3, 2026

25 papers—21 primary·4 cross-listed

01
Natural Phantom Crossing from Axion-WIMP Interactions
Cédric Delaunay🇫🇷 · Seung J. Lee🇰🇷 · Yuan Yin🇰🇷 · Bingrong Yu🇺🇸
We construct a technically natural model in which thermal dark matter (DM) interacts with axion dark energy (DE) and produces an apparent late-time crossing of the phantom divide. A direct axion coupling to weakly-interacting massive particles (WIMPs) would ordinarily radiatively destabilize the ultralight axion potential. We avoid this issue through $N$ fermion species related by a cyclic $Z_{N}$ symmetry, which projects the leading Coleman-Weinberg potential onto the exponentially suppressed $N$ th harmonic. Although the microscopic theory preserves $Z_{N}$ , the axion-dependent WIMP masses generate unequal equilibrium abundances that freeze-out imprints on the cosmological relic state, thereby breaking the symmetry spontaneously. The resulting relic distribution retains a memory of the initial axion value and generates an unsuppressed finite-density potential that holds the field fixed at early times. As the WIMP density dilutes, the axion rolls toward the minimum of its confining potential, transferring energy from DE to DM at late times. An observer assuming separately conserved components then infers an effective equation of state that crosses below $- 1$ , without ghosts or violation of the null-energy condition. We present an illustrative cosmological solution with a DESI-like phantom crossing and percent-level suppression of structure growth, and discuss the implications of the WIMP multiplicity and relic distribution for DM searches.
hep-phastro-ph.CO1 citation
02
Gravity Probe-DM: The Gravitational Laboratory for Dark Matter
Yu-Dai Tsai🇺🇸 · Hayden R. Foote🇺🇸
Dark matter is inferred gravitationally across the Universe but has not been detected within the Solar System. The Sun inevitably focuses incident unbound dark matter into an irreducible downstream wake. Its structure encodes the incoming density and velocity distribution and, for wave dark matter, the de Broglie scale. We propose Gravity Probe-DM, a heliocentric search using precision ranging between spacecrafts. The exact two-spacecraft observable is the differential wake acceleration; for a short baseline, it becomes the wake tidal tensor projected along the baseline. For a $2.5 \times 1 0^{6} km$ baseline crossing a $0.1 AU$ coherent width at $30 km s^{- 1}$ , a one-percent excess gives a raw uniform-core range scale of $0.63 pm$ over $5.77 d$ . While the projected tide remains coherent over an interval $T$ , the free response grows as $T^{2}$ , reaching $2.5 nm$ over one year. An illustrative low-lag dark-disk component carrying $20%$ of the reference local density and reaching a $30%$ focused contrast gives a one-year scale of about $15 nm$ . These pre-fit response scales show that trajectory design can move the signal from sub-picometre to nanometre scales. A detection would provide a purely gravitational map of local dark matter and probe the flow that produced it, including particle versus wave focusing. The Sun supplies the lens, spacecraft sample the wake, and precision ranging reads out its gravitational imprint.
hep-ph0 citations
03
Hadron Structure from the Hierarchy of Quantum Correlations in Deep-Inelastic Scattering
Henry Bloss🇺🇸 · TJ Hobbs🇺🇸 · Navin McGinnis🇺🇸
We show that the hierarchy of quantum correlations produced in deep-inelastic scattering (DIS) can serve as a novel probe of the proton's nonperturbative structure. Specifically, we show that quantum entanglement, discord, steering, and magic provide nontrivial and complementary sensitivities to the nucleon's parton distribution functions (PDFs), particularly those encoding the transverse-spin polarization of the interacting quark. This connection leads to a unique probe of the proton's parton-level tensor charges with implications for beyond Standard Model (BSM) physics searches. We propose how quantum information measures can be utilized for precision studies of hadron structure at DIS experiments like the upcoming Electron-Ion Collider (EIC).
hep-phquant-ph5 citations
04
A geometric origin for the radiative neutrino portal to secluded dark matter
Mattia Di Mauro🇮🇹
We study a secluded dark-matter scenario in which the smallness of laboratory signals is linked to the origin of neutrino masses. In the four-dimensional theory, the dark sector contains a hidden scalar, a fermionic dark-matter particle, and heavy Majorana neutrinos. The same heavy-neutrino sector that generates light neutrino masses via the seesaw mechanism also induces the Higgs-dark-scalar portal at one loop. This portal is tied to the small observed neutrino masses, naturally leading to very small Higgs-singlet mixing and suppressed signals in direct-detection and collider experiments. We then provide a geometric origin for the boundary condition of the tree level portal coupling being zero $κ (Λ_{UV}) = 0$ via a five-dimensional sequestered setup. In this construction, the Standard Model fields and the hidden sector are localized on different branes, with sterile neutrinos propagating in the bulk. Five-dimensional locality forbids a fundamental local tree-level Higgs-dark-scalar contact interaction, while heavy-neutrino loops induce a small residual portal coupling. The main phenomenological parameter controlling the viability of the model is the heavy-neutrino mass scale: direct detection bounds it from above, while Big Bang nucleosynthesis bounds it from below through the requirement that the hidden scalar decays sufficiently early. Depending on the amount of five-dimensional sequestering, the viable region can span heavy-neutrino masses from the multi-TeV scale to the PeV scale, or even higher.
hep-phhep-th0 citations
05
Quantum Tomography of Top Quarks as a Probe of Charge-Parity Violation
Eren Erdogan🇺🇸 · Kirtimaan A. Mohan🇺🇸 · Keping Xie🇺🇸 · Marcel Yanez🇺🇸
LHC measurements now reconstruct all fifteen parameters of the $t t ˉ$ two-qubit spin density matrix, which amounts to a full quantum tomography of the pair. We show that this data constrains CP violation in the top-Yukawa coupling. The coupling enters the density matrix at one loop and produces spin correlations that are odd under CP and do not affect the cross section. Using the first complete renormalized one-loop density matrix and the experimental covariance, we obtain complementary constraints comparable to those from direct tree-level $t t ˉ H$ and $t H$ production.
hep-phhep-exhep-th0 citations
06
Molecular clouds constraints on sub-GeV DM and asteroid-mass PBHs
Asier Salces Pérez🇪🇸 · Pedro de la Torre Luque🇪🇸
We show that the ionization of molecular clouds provides a novel probe of dark matter scenarios producing low-energy $e^{+} e^{-}$ pairs through annihilation, decay, or Hawking evaporation of primordial black holes. We derive constraints on MeV-scale dark matter with masses between $\sim 1$ and $100$ MeV, as well as on primordial black holes in the mass range $1 0^{14}$ -- $1 0^{17},$ g. By modeling the propagation of electrons and positrons inside molecular clouds, we show that uncertainties in charged-particle transport constitute the main limitation of this method. Nevertheless, for the most physically motivated propagation scenarios, the resulting constraints remain competitive with the strongest bounds currently available. We also identify the molecular-cloud properties that maximize the sensitivity to dark matter-induced ionization and discuss how larger samples of clouds, together with improved modeling of cosmic-ray ionization and cloud structure, could substantially enhance the reach of this technique. Our results establish molecular-cloud ionization as a promising and complementary probe of sub-GeV dark matter and evaporating primordial black holes.
hep-phastro-ph.HE0 citations
07
Dark Photon - ALP Freeze-in: 511 keV and H $α$ Constraints
Simran Arora🇮🇳 · Nandini Das🇮🇳 · Sukanta Dutta🇮🇳 · Ashok Goyal🇮🇳
We investigate a freeze-in scenario of two component dark matter consisting of an axion-like particle (ALP) and a dark photon. The dark sector connects to the Standard Model through a dimension-five ALP-dark photon interaction, while a small kinetic mixing governs dark photon decays. Solving the coupled Boltzmann equations, we determine the parameter space consistent with the observed relic abundance. We find that, for a nearly degenerate dark sector, dark photon decay into an electron-positron pair through the kinetic mixing explains the Galactic 511 keV line while the dimension five operator can source the necessary production of dark photon and ALP particles to satisfy the relic density. We further confront the model with recent H $α$ observations of dwarf galaxies, together with constraints from the cosmic microwave background, diffuse gamma rays, direct detection and collider searches. We identify viable regions of parameter space yielding $Ω_{DM} h^{2} ≃ 0.12$ , with an effective scale $Λ \sim 1 0^{10}$ - $1 0^{12}$ GeV, and dark photon lifetimes of order $1 0^{26}$ - $1 0^{29}$ s, while remaining consistent with the observed 511 keV photon flux, $H α$ constraints from Leo T and all other astrophysical constraints.
hep-ph0 citations
08
Dark Photon Dark Matter from Quantum Fluctuations during Starobinsky Inflation
Taiyo Kasamaki🇯🇵 · Takeo Moroi🇯🇵
We present a detailed investigation of scenarios in which dark-photon dark matter is produced from quantum fluctuations during inflation. In particular, we focus on inflationary models that necessarily involve a Weyl transformation, dependent on the inflaton amplitude, in order to move to the Einstein frame. In such models, the kinetic function of the longitudinal mode of the dark photon varies throughout, and even after, the inflationary period. We show that this variation of the kinetic function has a substantial impact on the resulting relic abundance of dark photons. As a representative and phenomenologically important example, we analyze the Starobinsky inflation model, for which we perform an accurate computation of the relic dark-photon abundance. By imposing the relevant observational constraints, we find that, in order to reproduce the observed dark-matter density in the present Universe, the dark-photon mass must lie in the range $5.6 < m < 7.4 μ eV$ within the framework considered in this work.
hep-phastro-ph.COgr-qchep-ex1 citation
09
Pentaquark Bound States and Regge Trajectories in QCD via Bethe Salpeter Formalism
M.Ghaderi🇮🇷 · N. Tazimi🇮🇷 · M. Monemzadeh🇮🇷
We present a comprehensive calculation of pentaquark masses and Regge trajectories within the framework of the Godfrey-Isgur relativized quark model. The pentaquark is treated as a meson-baryon molecular system, and the bound state is solved using the Bethe-Salpeter equation with the effective meson-baryon interaction motivated by GI, including smearing, running coupling, and spin-spin interactions. Using the latest PDG data for the known Pc and Pcs states, we compute the ground state and first two radial excitations for four pentaquark candidates: Pc(4440), Pc(4457), Pcs(4338), and Pcs(4459). The calculated masses are in excellent agreement with experiment. We also construct radial Regge trajectories in the (n, M^2) plane. Within the three calculated radial levels, the trajectories are approximately linear, with slopes comparable to those reported for ordinary hadrons. These results are consistent with a common confinement-driven pattern, but do not establish its universality.
hep-ph0 citations
10
Rare processes in ultrahigh-energy tau-lepton transport
Guo-yuan Huang🇨🇳
In cosmic neutrino observatories, charged-lepton transport is a key input for interpreting observables and reconstructing neutrino events. Charged leptons propagating through matter undergo several energy loss processes, such as electron pair production and photonuclear interaction. In this work, we investigate several rare processes in tau-lepton transport, focusing primarily on muon pair production, $τ N \to τ μ^{+} μ^{-} N$ , and Primakoff neutral-pion production, $τ N \to τ π^{0} N$ . At EeV energies, we find that the energy loss contributions from muon pair and Primakoff pion production are only $0.6%$ and $0.2%$ , respectively, of that from electron pair production. Nevertheless, dimuon production may be relevant to tau neutrino searches in underwater and under-ice Cherenkov telescopes. The interaction length for dimuon emission by an EeV tau is only $6 km$ in standard rock. Such events may be identified through the lateral separation of dimuon tracks or through a kebab topology if tau decays in the detector.
hep-phastro-ph.HEhep-ex0 citations
11
Weak Bose-Einstein condensation in a rigidly rotating magnetized charged Bose gas
E. Siri🇮🇷 · N. Sadooghi🇮🇷
We investigate the weak Bose-Einstein condensation (BEC) scenario of a noninteracting charged Bose gas simultaneously subjected to a strong magnetic field and rigid rotation. Using standard methods of finite-temperature quantum field theory and the generalized Fock-Schwinger formalism, we derive the corresponding thermodynamic potential in the nonrelativistic and lowest Landau level approximations. An appropriate modification of the effective chemical potential yields a consistent thermodynamic description and naturally introduces a magnetorotational fugacity. Within the high-temperature approximation, rigid rotation enters the thermodynamics solely through the Tolman-Ehrenfest local temperature. We demonstrate that rigid rotation does not qualitatively modify the weak BEC scenario induced by Landau quantization. The magnetorotational fugacity remains below unity throughout the phenomenologically relevant temperature range, while the continuous evolution of the ground state population and the absence of a singularity in the specific heat provide complementary signatures of the persistence of weak BEC. We further study the thermodynamic properties of the system under conditions relevant to quark-gluon plasma and neutron-star matter. We show that rotational effects are much more pronounced in the former. Our analysis reveals a new magnetic response to rigid rotation: while magnetic fields enhance diamagnetism, rotation drives it toward paramagnetism. This behavior reflects a competition between magnetic quantization and rotational orbital motion, emphasizing the role of rotation in shaping the magnetic response of bosonic matter.
hep-phnucl-th0 citations
12
Classification of minimal models producing b, c and tau masses at one-loop level
Lucia Stockdale · Raymond R. Volkas🇦🇺
The Standard Model neither provides a dynamical explanation for the quark and lepton mass hierarchies, nor a rationale for why all of these masses save that of the top quark are suppressed compared to the electroweak scale. Motivated by this, we explore the alternative radiative mass generation hypothesis, specialising to the generation of the bottom, charm, and tau masses at one-loop level. A classification of all minimal models that use exotic scalars and exotic fermions only is presented, resulting in 25 possibilities featuring four exotic multiplets. As a bonus, some of the models produce a one-loop neutrino Dirac mass if a right-handed neutrino field is included, and some feature WIMP-like dark matter candidates. By way of example, we analyse the phenomenology of a benchmark model chosen from the set of 25 candidates and find that it is capable of exactly replicating the predicted Standard Model Yukawa couplings within the permitted parameter space.
hep-ph0 citations
13
pylhe: A Lightweight Python interface to Les Houches Event files
Alexander Puck Neuwirth🇮🇹 · Matthew Feickert🇺🇸 · Lukas Heinrich🇩🇪 · Eduardo Rodrigues🇬🇧
Les Houches Event files are a standard format for Monte Carlo event generators in high-energy physics. pylhe is a lightweight pure-Python library for reading and writing LHE event data. It supports .lhe and compressed .lhe.gz files, implements the widely used LHE 3.0 features including multiple event weights and generator metadata, and also supports the recent HDF5-based LHEH5 format. By exposing events through a pythonic iterator and shared data structures, pylhe enables memory-efficient processing of large event samples without loading entire files into memory. The library also supports format conversion and integration with modern analysis workflows, including columnar analysis with Awkward Array and downstream machine-learning applications.
hep-ph0 citations
14
Halbach Magnetic Weber Bars
Valerie Domcke🇨🇭 · Itay M. Bloch🇨🇭
Magnetic Weber Bars have been proposed to search for gravitational waves in the kHz to GHz regime by exploiting the mechanical deformation of a large magnet induced by a gravitational wave. Here we propose to increase the effectiveness of such devices by considering magnetic field configurations with strong gradients, albeit lower field strengths, such as Halbach arrays. We focus on one of the most challenging but most realistic signals, with short duration and low coherence, exploiting the ring-down period of the mechanical resonator. We show that with demonstrated technology this setup can reach sensitivities of $S_{h}^{1/2} ≃ 1 0^{- 21} / Hz$ at a broad set of frequencies around several resonance peaks at $\sim 10$ kHz, and $S_{h}^{1/2} ≃ 5 \cdot 1 0^{- 20} / Hz$ in a broadband search at higher frequencies. We discuss plausible upgrades to reach $S_{h}^{1/2} ≃ (1 0^{- 23} - 1 0^{- 21}) / Hz$ in a broadband search covering 10 kHz - MHz.
hep-phastro-ph.IMgr-qchep-ex0 citations
15
The price for monopole dark matter
Felix Brümmer🇫🇷 · Giacomo Ferrante🇧🇪 · Théodore Fischer🇫🇷 · Michele Frigerio🇫🇷
We construct an explicit model where dark matter consists of 't Hooft-Polyakov monopoles. The dark sector is in thermal contact with the Standard Model, and dark monopoles are created by a thermal phase transition in the early Universe. Generically, the abundance of monopoles is negligible with respect to that of stable dark elementary particles. We show how to avoid this by taking the lightest stable particle, a dark fermion, sufficiently light for its abundance to be suppressed, yet heavy enough to satisfy constraints on dark radiation. In this specific window of parameters, dark matter is composed of monopoles with a mass of about $1 0^{8}$ GeV or larger, depending on the nature of the phase transition. This candidate lies beyond the reach of present, conventional dark-matter detection experiments. However, the model necessarily predicts dark radiation, with $Δ N_{eff}$ close to present-day bounds. In addition, if the dark phase transition is strongly first order, we find that the corresponding gravitational wave spectrum lies close to the region probed by future interferometers.
hep-phastro-ph.COhep-th1 citation
16
The fundamental limit of jet tagging: Beyond top jets
Sarah Koller🇩🇪 · Humberto Reyes-González🇩🇪
Jet tagging, i.e. determining the origin of high-energy hadronic jets, is a key challenge in particle physics. Machine-learning-based taggers have achieved remarkable progress, raising the question of how close current methods are to the theoretical limit of performance. Previous work addressed this question for boosted top-quark jets using transformer-based generative models that provide realistic synthetic jet data with known probability density functions. This enables a direct comparison between modern taggers and the optimal likelihood-ratio classifier. In this note, we summarize the approach and extend the study to boosted W, Z, and H $\to g g$ jets. We find that the gap to the estimated optimal limit is strongly jet dependent and is substantially reduced for these seemingly more challenging tagging tasks. Ongoing work aimed at understanding the interpretation, robustness, and scaling of these limits is also briefly discussed.
hep-ph0 citations
17
Penumbral Inflation from Calabi-Yau Boundaries
Pirzada🇨🇳 · Tianjun Li🇨🇳
Mapping Calabi-Yau geometry to early Universe cosmology remains a primary goal in string phenomenology. We present an inflationary mechanism where flux stationarity shifts the field dynamics, driving inflation along the volume-controlling saxion direction near a Hodge boundary. In this region, the internal geometry strictly dictates the scalar potential. This setup stabilizes the field against heavy moduli corrections without consuming extra flux tadpoles. As a result, the properties of the geometric boundary translate directly into primordial tensor perturbations, creating a clear physical link from string compactifications to measurable data. The resulting geometric predictions match current cosmic microwave background limits and provide specific, testable targets for upcoming LiteBIRD and CMB-S4 observations.
hep-phgr-qcmath-phmath.MP0 citations
18
New $C P$ sum rules from exact $U$ -spin degeneracy
Chao-Qiang Geng🇨🇳 · Chia-Wei Liu🇨🇳 · Sheng-Lin Liu🇨🇳 · Bing-Bo-Min Shang🇨🇳
We propose a new class of $C P$ sum rules in the $U$ -spin limit, based on the observation that the weak phase in the Standard Model can be removed in the degenerate limit $m_{d} = m_{s}$ . Unlike previous $U$ -spin analyses formulated at the amplitude level, our sum rules are expressed directly in terms of decay widths. They apply to matched partial waves, spin observables, and angular moments and include nonpairwise cases beyond the usual single-insertion $d \leftrightarrow s$ relation.
hep-phhep-ex1 citation
19
Inflation and Reheating by Dynamical Torsion
Xiaolin Ma🇯🇵 · Kamil Mudrunka🇯🇵 · Kazunori Nakayama🇯🇵
In gravity theories with torsion, inflation can be driven by the dynamical torsion. Since it naturally has a derivative coupling to the axial current consisting of Standard Model particles, the reheating dynamics should be much different from conventional inflation models like Starobinsky inflation. We calculate the inflaton decay rate in detail and find that, although the 2 body decay into the fermion pair is vanishing in the massless fermion limit, the anomaly-induced 2 body decay into the gauge bosons and 3 body decay involving the Higgs boson are non-vanishing and they give sizable contributions to the total decay width of the inflaton. This gives a natural lower bound on the reheating temperature in the inflation model with dynamical torsion.
hep-phastro-ph.COgr-qc1 citation
20
Sgoldstino Phenomenology at SND@HL-LHC
D. Kalashnikov🇷🇺 · E. K. Karkaryan🇷🇺
We study the phenomenology of light scalar sgoldstinos, with masses from the dimuon threshold up to a few GeV, focusing on their production and detection prospects at the SND@HL-LHC experiment. We review the effective sgoldstino interactions with Standard Model particles, the dominant meson-decay production channels, and the relevant experimental constraints on the model parameter space. We also outline the recently proposed SND@HL-LHC detector configuration and discuss the kinematics and track separation of the muon pair produced in sgoldstino decays inside the detector volume. For two representative sets of supersymmetry-breaking parameters, we present sensitivity estimates and show that the muon-antimuon separation efficiency should be taken into account in searches for the dimuon signal.
hep-phhep-ex0 citations
21
Dark Photons from Perturbative Decay of a Misaligned Higgs Field
James M. Cline🇨🇦 · Gonzalo Herrera🇨🇦 · Jean-Samuel Roux🇨🇦
We reconsider the production of dark photons $A^{'}$ as dark matter, from the perturbative decay of a dark Higgs field $h$ , that is stochastically misaligned from the minimum of its potential during inflation. This is a simple and predictive framework for generating the $A^{'}$ relic abundance. It is constrained by structure formation, since the $A^{'}$ are initially boosted, and inflationary isocurvature fluctuations, which require small quartic couplings $λ h^{4}$ . We identify $A^{'}$ masses between 100 eV and 1 GeV and gauge couplings $g \sim 1 0^{- 15} - 1 0^{- 10}$ that are consistent in this scenario, and which become more tightly constrained if a generic level of kinetic mixing is present. The favored parameter region could be tested through future CMB or Lyman- $α$ observations, and, in the presence of kinetic mixing, by direct detection experiments or diffuse soft gamma-ray searches.
hep-phastro-ph.COastro-ph.HE0 citations
22
From Horizon Microstates to the Black Hole Membrane
Chong-Sun Chu🇹🇼
The membrane paradigm represents a black-hole horizon by a fictitious conducting surface. We derive a microscopic electromagnetic membrane from black-hole matrix quantum mechanics. The fuzzy-sphere horizon carries a Berry monopole, placing its fundamental fermionic partons in lowest-Landau-level states with Ohmic and Hall responses. Off-diagonal bifundamental modes connecting the horizon and exterior matrix blocks become tachyonic near the horizon and condense, dynamically coupling the horizon gauge field to the exterior Maxwell field. In the low-frequency regime $ω R ≪ 1$ , the fixed-parton transport description predicts frequency- and helicity-dependent reflectivity. At larger frequency, real parton excitations require a black-hole $S$ -matrix. Ohm's law then fixes the inclusive absorption probability; unitarity bounds the local absorption cross section by the horizon area, with the classical conductivity $1/4 π$ saturating this maximal-absorption bound.
↳ hep-thgr-qchep-ph2 citations
23
Energy-dependent Optical/Near-infrared and X-ray Correlations in Swift J1727.8-1613
Ruican Ma🇬🇧 · Federico Vincentelli🇬🇧 · Diego Altamirano🇬🇧 · Alexandra Veledina🇫🇮 · Poshak Gandhi🇬🇧 · Piergiorgio Casella🇮🇹 · Tariq Shahbaz🇪🇸 · Sian Woahene-Demehin🇬🇧
We present a timing analysis of the black hole transient Swift J1727.8-1613 during its intermediate state. We use coordinated broadband X-ray observations from Insight-HXMT (2-150 keV), together with optical data from ULTRACAM (g_s and i_s bands) and near-infrared data from HAWK-I (K_s band), obtained on 2023 September 9. As shown by previous studies, the Fourier power spectrum shows a strong quasi-periodic oscillation (QPO) in the K_s, i_s and X-ray bands. Cross-correlation analysis reveals a complex coupling between the optical/near-infrared (OIR) and X-ray emission, including a delayed optical anti-correlation, a strong infrared correlation, and a pronounced dependence of these features on X-ray energy, suggesting multiple Comptonisation regions. In contrast, the lag properties do not change at the QPO frequency, displaying an OIR lag of ~60-80 ms up to 150 keV. We discuss these results in the context of small-scale jet and hot accretion flow scenarios.
↳ astro-ph.HEhep-phMNRAS(2026)·0 citations
24
A Quantitative Framework for Testing the Hubble Tension in a Bianchi Type I Cosmological Background
Luigi Tedesco🇮🇹
The Hubble tension is usually formulated as a disagreement between two determinations of a single scalar parameter, $H_{0}$ , within an isotropic FLRW model. We develop a quantitative framework treating the tension as a consistency test of the scalar FLRW compression of cosmological data in a homogeneous, anisotropically expanding Bianchi type I background. Beyond synthesizing established results on Bianchi I kinematics, null geodesics, and optical propagation, our original contribution is a worked weak-shear, axisymmetric calculation mapping a specified shear history into a low-redshift luminosity-distance quadrupole. The calculation explicitly separates the direction-dependent redshift--affine-parameter mapping from the Jacobi-focusing contribution, propagating the resulting distance quadrupole through an analytic polar-cap toy window. For freely decaying shear, we obtain $A_{D} (z) = - B_{H 0} + (2 q_{0} - 1) B_{H 0} z /2 + (5 - q_{0} - 18 q_{0}^{2} + 6 j_{0}) B_{H 0} z^{2} /12 + O (z^{3}, B_{H 0}^{2})$ , where $B_{H 0} = (H_{∥ 0} - H_{⊥ 0}) / H_{0}$ and $j_{0}$ is the mean jerk parameter. A representative BBN limit, $Ω_{σ 0} \leq 1 0^{- 23}$ , implies $∣ B_{H 0} ∣ \leq 9.5 \times 1 0^{- 12}$ and a distance-modulus quadrupole below $2.4 \times 1 0^{- 11}$ mag at $z = 0.15$ . The early-Universe bound used is adopted from prior work; the novelty lies in propagating it through the derived Sachs--Jacobi mapping into limits on the luminosity-distance quadrupole and catalogue-window bias. By contrast, a 1% directional shift requires $Ω_{σ 0} \approx 2.5 \times 1 0^{- 5}$ , while matching the Planck 2018--SH0ES 2022 separation requires $Ω_{σ 0} \approx 1.8 \times 1 0^{- 3}$ . Thus, the minimal shear-only model cannot resolve the tension, though the framework supplies a falsifiable programme for testing late-time anisotropy with SNe, BAO, and standard sirens.
↳ astro-ph.COgr-qchep-phhep-thUniverse(2026)·0 citations
25
Generalized parton distributions from lattice QCD
Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸
This chapter gives an overview of the recent progress in extracting generalized parton distributions from lattice QCD. We briefly recall the theoretical principles of GPDs and explain the two most common lattice approaches, Ji's quasi-distributions and Radyushkin's pseudo-distributions. In the second part of the chapter, we review the lattice results obtained from these two frameworks. Finally, we offer a discussion of future prospects of lattice extractions of GPDs.
↳ hep-lathep-exhep-phhep-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE