HEP Phenomenology·hep-ph

Mon·Oct 5, 2026Monday·October 5, 2026

28 papers—20 primary·8 cross-listed

01
BootLoops: an LLM-driven toolkit for exact quantitative science
Matthew D. Schwartz
Much of quantitative science involves difficult mathematical computations: a Feynman integral, evidence for an evolutionary tree, or a regulatory statistic. These are often estimated by Monte Carlo or heuristic search, or computed in floating point without tracking rounding error. Exact methods often exist, but in a field far from the problem. The reduction methods of collider physics also work on a Bayesian evidence, and a regulatory threshold can be settled with interval arithmetic from numerical analysis, but few people know both fields. A large language model knows both, and every other field, and with working programs in hand it can carry a method from one to another. BootLoops is a pool of such programs: integral reduction, differential equations and high-precision evaluation from particle physics, integer-relation fitting from experimental mathematics, exact enumeration, and ball arithmetic, in one toolkit that any agentic large language model can operate and extend. These tools can compute multi-loop Feynman integrals by bootstrap methods rather than direct integration, across the function classes that arise, including polylogarithms, elliptic functions, and periods of K3 surfaces and Calabi-Yau manifolds. They can also evaluate Bayesian evidence integrals as exact rational numbers, enumerate finite configuration spaces with proof of completeness, show when a sought closed form cannot exist, and redo floating-point calculations with guaranteed digits. In practice this brings the tools of mathematics, computer science and physics to problems in genomics, statistics, ecology and other fields. The toolkit and its documentation are at https://bootloops.ai.
hep-ph
02
Shining LIMelight into the dark: Probing Dark matter - baryon interactions with Line Intensity Mapping
Durba Ghosh · Ranjini Mondol · Ranjan Laha
Line-intensity mapping (LIM) is an emerging technique for probing both the astrophysics of galaxy formation and the cosmological evolution of large-scale structure. We investigate, for the first time, its potential as a probe of dark matter-baryon (DM- $b$ ) interactions using the upcoming Carbon Monoxide Mapping Array Project (COMAP) surveys, COMAP-EoR (Epoch of Reionization) and COMAP-ERA (Expanded Reionization Array). Elastic scattering of dark matter (DM) with baryons, i.e., protons ( $p$ ) and electrons ( $e$ ), exchange momentum and heat with the DM, suppressing structure formation and leaving characteristic signatures in the linear matter power spectrum. These effects propagate to the LIM power spectrum (PS) and voxel intensity distribution (VID). We consider momentum-transfer cross sections $σ_{T, n}^{χ b} = σ_{n}^{χ b} v^{n}$ , with $n = 0, - 2,$ and $- 4$ , corresponding to contact, electric dipole-moment-like, and Coulomb-like interactions, respectively. Using Fisher forecasts, we obtain the projected sensitivities to $σ_{n}^{χ b}$ from the PS and VID. Our VID-only forecasts combining the 16 and 30 GHz observed bands yield stronger sensitivities than existing cosmological limits for $n = - 2$ and $n = - 4$ for sub-GeV DM masses. We also explore the potential of combining the PS and VID to probe these interactions. Our study highlights LIM as a complementary probe of DM models alongside other astrophysical, cosmological, and terrestrial searches.
hep-ph
03
How Quantum Is Bottomonium in the Quark-Gluon Plasma?
Nora Brambilla · Tom Magorsch
We study how much quantum structure bottomonium retains during its evolution in the quark-gluon plasma. Within the open quantum system framework, we simulate the Lindblad equation obtained from potential nonrelativistic QCD in the quantum Brownian regime. From the resulting real-time evolution of the bottomonium density matrix, we compute the Wigner transform and study its negativity as a measure of nonclassicality and a test of a key condition underlying classical Langevin-type approximations. We find that the medium suppresses the negativity, which nevertheless approaches a finite plateau close to that of the $1 S$ state. The overlaps with the excited $2 S$ and $3 S$ states arise from near-canceling positive and negative phase-space contributions, driven by negative regions in the Wigner transforms of the bound-state projectors, while the $1 S$ overlap is insensitive to such contributions. We further show that the position-space coherence is similarly suppressed and plateaus close to the 1S value. We trace the finite residual quantum structure to conditional purification: the medium preferentially dissolves weakly bound and unbound modes with large $⟨ r^{2} ⟩$ , driving the surviving singlet $S$ -wave ensemble toward the $1 S$ state. More broadly, these results reveal that classicalization is partial and observable dependent, a feature that is relevant across applications of open quantum system methods in fundamental physics.
hep-phhep-exnucl-exnucl-th+1
04
Towards Hadronisation on GPUs
Siddharth Sule
Complete event generation on hardware accelerators such as GPUs requires vectorising the algorithms of components such as parton showers and hadronisation. To this end, I implemented a simplified cluster hadronisation and hadronic decay model in the GPU parton shower program GAPS, with one thread per event and each stage of the algorithm as a separate kernel. I compared simulation results for $e^{+} e^{-} \to hadrons$ at the $Z$ pole with the Herwig event generator and with ALEPH and L3 data, and measured execution times on an NVIDIA V100 GPU. The results agree well with Herwig, and GAPS generates one million hadron-level events (NLO hard process, shower, hadronisation and decays) in about four seconds on this GPU.
hep-ph
05
Derivation of color projectors on multi-quark states using the Casimir operator
Stéphane Peigné · Clément Liesse
We present an elementary recursive construction of Hermitian projectors on multi-quark $SU (N)$ color states, based on the characterization of these states by their quadratic Casimir, and using the birdtrack pictorial technique.
hep-phhep-th
06
Precise QCD Predictions for Photon-Associated Hadron Production at the LHC
Gabriele Fiore · Aude Gehrmann-De Ridder · Alexander Huss · Francesco Merlotti · Giovanni Stagnitto
Prompt-photon production with recoiling QCD radiation is crucial for new-physics searches, determinations of parton distribution and fragmentation functions, and jet-quenching studies in heavy-ion collisions. We present the first fully differential NNLO QCD predictions for photon-associated identified-hadron production at the LHC. We compare predictions obtained with different fragmentation function (FF) sets to ALICE and ATLAS data at $s = 5.02 TeV$ . Our calculation provides an important theoretical ingredient for FF global fits and offers a precision proton--proton baseline for photon-tagged heavy-ion studies.
hep-phhep-ex
07
High Energy Neutrinos, Gravitational Waves, and Dark Matter from a Cosmological First Order Phase Transition
James M. Cline · Savas Stoica · Yong Xu
We investigate high energy neutrinos (HE $ν$ s) from the decay of superheavy dark matter (DM) produced during a cosmological first order phase transition. Adopting the filtered DM production mechanism, we revisit the relic abundance calculation by incorporating recent progress in determining the bubble wall velocity from hydrodynamics. We show that DM with mass $m_{DM} ≃ 4.4 \times 1 0^{8} GeV$ can reproduce the observed relic abundance and accommodate ultra high energy neutrino events such as KM3-230213A, while the same phase transition simultaneously generates a stochastic gravitational wave (GW) background. Although the GW signal (which peaks at $1 0^{4} Hz$ ) is not yet observable in this example, at lower DM masses $m_{DM} ≲ 1 0^{6} GeV$ , the neutrino spectrum shifts into the energy range relevant for IceCube observations, while the associated GW signal moves to lower frequencies and can reach the projected sensitivities of Cosmic Explorer, BBO, and DECIGO. This gives a multimessenger connection between HE $ν$ s and GWs, with both signals connected to DM production in a first order phase transition.
hep-phastro-ph.CO
08
$S U (N)$ baryon formation in the early Universe and dark matter
Luca Di Luzio · Samuele Di Valeriano · Enrico Nardi
We study the formation of $N$ -quark baryons during the confinement crossover of an $S U (N)$ gauge theory containing quarks in the fundamental representation, with masses around or below the confinement scale. We assume stepwise baryon formation through the successive fusion of pairs of quark-clusters, with color interaction rates obeying quadratic Casimir scaling. We include the complete set of reactions between $S U (N)$ antisymmetric clusters dressed with their specific spin-flavor multiplicities. We show that at large $N$ , baryon formation is hindered by a Casimir bottleneck, such that fusion of few-quark clusters in the initial steps of the baryon assembly chain is strongly outweighed by cluster destruction processes. We find that for $N = 12 (18)$ the baryon-to-meson yield ratio is suppressed down to $1 0^{- 12} (1 0^{- 23})$ of its value at $N = 3$ . We embed the mechanism in a vectorlike three-flavor model whose lightest baryon can be electrically neutral, while axial-anomaly-induced couplings and dimension-six operators induce decays of the unstable mesons and charged baryons safely before big-bang nucleosynthesis. The relic density of cosmologically stable neutral $N$ -baryons is thus set during confinement at values so small that, for sufficiently large $N$ , the baryon masses required to saturate the dark matter energy density exceed by several orders of magnitude the unitarity bound on annihilation cross sections.
hep-phhep-th
09
Photon Quantization and Propagator in Rotating Coordinates
Alejandro Ayala · Santiago Bernal-Langarica · Jorge David Castaño-Yepes · José Jorge Medina-Serna
We construct the quantized electromagnetic field and the corresponding photon propagators in a rigidly rotating cylindrical reference frame. Starting from covariant Maxwell theory, we formulate the gauge-fixed field equations and solve them in cylindrical coordinates. The vector nature of the electromagnetic field requires distinguishing orbital and intrinsic angular momentum, with the total angular momentum as the natural quantum number. We construct the two independent physical photon modes in terms of Bessel functions by solving the coupled differential equations, and provide an alternative construction based on a covariant basis of vector eigenfunctions generated by a covariantly constant tetrad. After normalizing the modes with the Maxwell inner product, we quantize the electromagnetic field and define the corresponding photon states and greater and lesser two-point functions. The physical time-ordered propagator is obtained directly from the quantized modes, with its transverse dependence encoded in polarization kernels that retain the cylindrical spatial structure and its spectral poles exhibiting the rotational energy shift. The full gauge-fixed photon propagator is constructed in two complementary ways: from the scalar Green function combined with the tensor transformation of the inertial Feynman-gauge propagator, and from the covariant vector eigensystem through its spectral decomposition and the Fock--Schwinger proper-time representation. We verify that both constructions satisfy the Green-function equation for the complete gauge-fixed Maxwell operator, providing the propagator required for covariant perturbative calculations with internal photon lines.
hep-phhep-th
10
Kinetic Equilibrium between SIMP Dark Matter and Radiation via Internal Bremsstrahlung
Xiaoyong Chu · Ajay Kaladharan · Yassine El Mohtadi
As an alternative to standard dark matter freeze-out via two-body annihilation, strongly interacting massive particles are proposed to regulate their relic abundance through three/four-body self-annihilation. During such freeze-out, dark matter must undergo both number reduction and energy dissipation. The former requires number-reducing processes, and the latter requires an efficient energy-dissipation mechanism. In this work, we propose a novel mechanism where internal Bremsstrahlung processes establish kinetic equilibrium between dark matter and radiation, and thus dissipate energy. More appealingly, this mechanism can be naturally realized in a class of strong dynamics models with flavor-universal quarks and a light axion. To demonstrate our results in a $S p (4)_{c}$ dark-color model, we compute all relevant interaction terms and numerically solve the full Boltzmann equations. The same mechanism can also be applied to vector dark matter models.
hep-phastro-ph.HE
11
Some Mathematical Methods Relevant to Analytical Calculations of Anomalous Magnetic Moments of Leptons
L.P. Kaptari · V.I. Lashkevich · O.P. Solovtsova
The mathematical methods and approaches used in our analytical calculations of electromagnetic corrections to the leptonic anomaly $a_{L}$ , which is caused by a special class of Feynman diagrams with insertions of the vacuum polarization operator, are presented and examined in detail. The developed methods are essentially based on the Mellin--Barnes transform for the propagators of massive particles with subsequent application of the PSLQ algorithm to solve the emerging functional equations. Functional equations are also used in the procedure of analytic continuation of a particular type of hypergeometric functions to the entire complex plane of their parameters. It is shown that these approaches make it possible to obtain explicit expressions for radiative corrections of rather high orders.
hep-ph
12
Final-state interactions in the $B^{\mp} \to K^{+} K^{-} π^{\mp}$ decays: traces of the $X (3700)$ state and CP asymmetry
Luciano M. Abreu · Eduardo Almeida · Patrícia C. Magalhães · Vinícius S. Silva
In this work, we investigate final-state interaction effects in $B^{\mp} \to K^{+} K^{-} π^{\mp}$ decays above 3 GeV with a twofold objective: (i) to study $C P$ asymmetry, and (ii) to search for possible signatures of the $X (3700)$ state (also denoted as $X (3720)$ ). We consider both tree-level and resonant contributions, with the latter arising from a triangle mechanism $B^{\mp} \to D ˉ^{0} D^{*\mp} (\to π^{\mp} D^{0}) \to K^{+} K^{-} π^{\mp}$ , in which the $D D ˉ \to K K ˉ$ rescattering process carries the signature of the exotic $X (3700)$ state. We analyze the dependence of our results on the relative phase between the tree-level and resonant contributions, as well as on other relevant parameters. We estimate the differential mass distribution in the region where the $X (3700)$ may leave a trace, and the $C P$ asymmetry driven by final-state interactions. Our findings are compared with available data for the differential mass distributions and the $C P$ asymmetry. Taken together, these results may contribute to a better understanding of the properties of exotic states and the role of $C P$ asymmetry in $B$ -meson phenomenology.
hep-ph
13
EOS version 1.1: A Software for Flavor Physics Phenomenology
Nienke C. Balz · Carolina Bolognani · Marta Burgos Marcos · Charles Earnshaw · Lorenz Gärtner · Nico Gubernari · Florian Herren · Matthew Kirk · Stephan Kürten · Viktor Kuschke · Domagoj Leljak · Philip Lüghausen and 9 other authors
EOS is an open-source software package for a variety of computational tasks in flavor physics. In this article, we describe new developments for version 1.1 of this software and discuss changes with respect to version 1.0. These developments and changes include theory predictions for additional decay and scattering processes, such as semileptonic charm decays, hadronic tau decays, and $e^{+} e^{-} \to$ hadrons scattering. Overall, these changes have contributed 1063 additional (pseudo-)observables. Beyond the physics capabilities of the software, the changes include improving the quality and reducing the computational costs of posterior sampling; providing a more versatile and testable figure framework; and improving the overall user experience.
hep-ph
14
Big Bang Nucleosynthesis Constraint on $B$ -mesogenesis
James M. Cline · Jonas Frerick · Sebastian A. Naja · Yong Xu
$B$ -mesogenesis is a low-temperature baryogenesis mechanism, that uses $C P$ -violation of the $B$ mesons in the standard model to fulfill the Sakharov conditions. It requires a late period of matter domination by a scalar field $Φ$ that decays into $b b ˉ$ quarks, reheating the Universe below the QCD phase transition. We investigate the impact of this mechanism on Big Bang Nucleosynthesis, with respect to the reheating temperature $T_{r h}$ , and the mass of $Φ$ . Injection of hadrons skewing neutron/proton interconversions are the most important effect, followed by neutrino heating from $Φ$ decays. For $M_{Φ} ≲ 100$ GeV, $T_{r h}$ must be $≳ 10$ MeV.
hep-phastro-ph.CO
15
Three-loop rapidity anomalous dimension for jet-veto cross sections
Samuel Abreu · Jonathan R. Gaunt · Pier Francesco Monni · Luca Rottoli · Robert Szafron
We present the first calculation of the third-order corrections to the rapidity anomalous dimension for jet-veto cross sections. This is a crucial ingredient for the resummation of these scattering observables in key processes such as colour-singlet and heavy-quark-pair production at hadron colliders. More precisely, our results enable the next-to-next-to-next-to-leading logarithmic (N $^{3}$ LL) resummation of the jet-veto cross section for colour singlet production at the LHC, with immediate phenomenological relevance. The anomalous dimension is extracted from a calculation of the three-loop soft function in soft-collinear effective field theory, and is presented as a function of the jet radius $R$ for the clustering algorithms of the generalised- $k_{t}$ family. To handle the complexity associated with the clustering algorithm, we formulate a semi-numerical computational approach. This strategy is itself a result of the paper, and can be extended to the calculation of other anomalous dimensions and soft functions at three loops.
hep-ph
16
NNLO QED corrections and inelastic two-photon exchange in elastic lepton-proton scattering with McMule
Matteo Ronchi
We supplement McMule, a Monte Carlo framework that provides QED corrections up to next-to-next-to-leading order (NNLO) in the fine structure constant $α$ , with the inelastic two-photon exchange (TPE) contribution, based on the data-driven dispersive calculation of Tomalak, Pasquini and Vanderhaeghen, which we extend to the $Q^{2} \to 0$ limit that enables applications in the low- $Q^{2}$ region relevant for upcoming low-energy experiments. We present results for two experimental settings: the future MAGIX@MESA experiment and the ISR@MAMI measurement. For MAGIX@MESA kinematics, the inelastic TPE is small, comparable to the proton-side NLO corrections and subdominant to both the leptonic radiative corrections and the full NNLO QED corrections once a 1 MeV photon-energy cut is applied. For the ISR@MAMI kinematics, NNLO QED corrections modify the radiative tail below the elastic peak at the 10% level.
hep-ph
17
Electroweak Transitions of Hyperons and Charmed Baryons: Opportunities and Prospects
Patrik Adlarson · Constantia Alexandrou · Simone Bacchio · Varvara Batozskaya · Johan Bijnens · Alexandre Brea Rodriguez · Gernot Eichmann · Andreas Konstantinou Andrzej Kupsc · Stefan Leupold · Piotr Salabura · Christoph Schwanda · Marcin Zieliński
We present a phenomenology-driven overview of opportunities and outstanding challenges in baryon electroweak transitions, focusing on hyperon and charmed-baryon processes for which lattice-QCD results are available, including semileptonic decays and selected radiative, dileptonic, and neutrino-induced channels. We identify semileptonic decays of strange and charmed baryons as a particularly promising domain for synergy between phenomenology, experiment, and lattice QCD. Particular emphasis is placed on the determination of vector and axial form factors, the precision and model-independent extraction of $∣ V_{u s} ∣$ from hyperon semileptonic decays including radiative corrections, and on searches for non-standard interactions through lepton-flavor- and CP-violating observables. We examine the momentum dependence of form factors in ground-state transitions, highlight the emerging $Ξ_{c} \to Ξ$ semileptonic puzzle stemming from tensions between lattice-QCD predictions and experimental measurements, discuss inclusive decay rates, and outline strategies for extending these studies to transitions involving excited baryon states. For completeness, we review also results involving beauty-baryon decays.
hep-ph
18
Third-Order Logarithmic Resummation for Jet-Vetoed Higgs Production
Samuel Abreu · Jonathan R. Gaunt · Pier Francesco Monni · Luca Rottoli · Robert Szafron
Jet vetoes are central to precision measurements of Higgs-boson properties at the Large Hadron Collider, where they are used to suppress backgrounds containing hard QCD radiation. We present the first prediction for the Higgs jet-vetoed cross section at the third logarithmic order in QCD, consistently combining the next-to-next-to-next-to-leading order calculation with state-of-the-art next-to-next-to-next-to-leading logarithmic resummation. At phenomenologically relevant veto scales ( $p_{T}^{v} \sim 30$ GeV) and jet radii ( $R = 0.4$ ), the resummation increases the fixed-order prediction by about $3%$ , and their combination leads to a residual perturbative uncertainty of approximately $3%$ . Our results mark a milestone in the precise description of jet-vetoed Higgs-production at hadron colliders, reaching the level of precision relevant for the high-luminosity phase of the LHC.
hep-phhep-ex
19
Higgsino dark matter compatible with the LUX-ZEPLIN high-energy nuclear-recoil event and IceCube constraints
Katherine Freese · Dionysios P. Theodosopoulos
We examine Higgsino dark matter (DM) as a potential explanation of the $248 keV$ nuclear-recoil event of interest reported by the LUX-ZEPLIN (LZ) experiment, taking into account IceCube constraints on DM annihilation in the Sun. In the nearly pure Higgsino limit, two neutral Majorana states separated by a small mass splitting $δ$ are connected by an off-diagonal coupling to the $Z$ boson, providing a natural realization of inelastic DM. Using a likelihood analysis, we identify 90\% confidence regions compatible with the LZ event and consistent with the null results of IceCube searches, both with and without including a constraint from the absence of events in the LZ high-energy sideband. In our LZ analysis, we consider the DM distribution in the Standard Halo Model alone as well as possible enhancements of the high-speed tail induced by the Large Magellanic Cloud (LMC). We present four variants of bounds from IceCube on Higgsino dark matter, depending on various assumptions on cooling channels in the Sun, motivated by severe theoretical uncertainties about Higgsino-nucleon elastic scattering (unimportant for direct detection but crucial for IceCube bounds). Whereas the thermal Higgsino with a mass of $1.1 TeV$ remains only marginally compatible with both the LZ event and the IceCube limits when the LMC-induced high-speed tail is included and both elastic cooling in the Sun and the LZ high-energy sideband constraint are neglected, higher mass Higgsinos are excellent candidates for the LZ event in light of IceCube constraints. Depending on the halo distribution, cooling interactions, and whether the LZ high-energy sideband is included, the compatible regions in the Higgsino parameter space $(m_{χ}, δ)$ extend from masses of $\sim 2 TeV$ to hundreds of TeV or higher, with mass splittings ranging approximately from $350$ to $525 keV$ .
hep-phastro-ph.COhep-th
20
Dark matter bound-states made easy
Simone Biondini · Stefan Vogl
A light force carrier can mediate long-range interactions between dark matter particles and facilitate the formation of bound states. Models incorporating these features have attracted considerable attention in recent years, with significant advances in both the theoretical understanding of such bound states and their impact on the parameter space consistent with the observed dark matter relic abundance. However, the relevant results and their consistent implementation in Boltzmann equations remain technically intricate, requiring careful treatment or the use of specialized tools. This complexity has hindered broader adoption of these findings and restricted their use to a small number of expert groups. To address this challenge, we propose a simple prescription based on the analytic limits of the relevant rates, which allows standard freeze-out computations to be refined through a straightforward semi-analytical prescription that captures the main features of the full calculation. We illustrate this approach for a $U (1)$ dark matter model with a light force carrier, including Sommerfeld enhancement and bound-state effects.
hep-ph
21
Unveiling Multimessenger Emission from Hidden Cores of Microquasars
Yu-Jia Wei🇺🇸 · Kohta Murase🇺🇸 · B. Theodore Zhang🇨🇳
Microquasars are radio-emitting X-ray binaries with relativistic jets and are established sources of $\sim 100$ ~TeV gamma rays, making them promising candidates for cosmic-ray acceleration. Motivated by recent detections of $\sim 100$ TeV photons from Cygnus~X-1 and multi-PeV photons from Cygnus~X-3, we employ the Astrophysical Multimessenger Emission Simulator (AMES) to model their multimessenger emission from radio to ultrahigh-energy gamma rays. Our modeling suggests that particle acceleration is extremely efficient in the jet region. The observed $≳ 0.1$ ~PeV gamma rays can originate from either $p γ$ or $pp$ interactions, depending on the location and physical conditions of the emission region, while also reproducing the lower-energy spectra. These configurations yield observationally testable predictions. In the poorly constrained $0.1$ - $10$ ~TeV band, the models predict either a deep valley, a mild suppression, or a power-law spectrum. Additionally, models involving compact emission regions comparable to the orbital separation predict strong variability, while those invoking more extended and static external zones show more stable behavior. We also provide a possible qualitative explanation for the energy-dependent modulation patterns, relying primarily on changes in the Doppler factor and external $γ γ$ absorption. In particular, explaining the PeV emission from Cygnus~X-3 favors a compact emission region, for which a magnetic field strength of order $1 0^{2} G$ is required. Finally, after accounting for pion and muon cooling, the predicted neutrino flux is suppressed, implying that detection is more challenging than previously thought.
↳ astro-ph.HEhep-ph4 citations
22
Intrinsic electromagnetic properties
Eduardo Barredo-Alamilla · Timur Z. Seidov · Daniel A. Bobylev · Maxim A. Gorlach
Electromagnetic properties of materials are commonly inferred from how they scatter light. Here we show that this diagnostic is fundamentally incomplete. We predict the existence of an intrinsic electromagnetic property that remains invisible in any scattering experiment independently of geometry, polarization, far-field or near-field excitation. Still, this property affects the radiation emitted by the sources embedded inside the material. We reveal this phenomenon for a specially designed nonreciprocal magnetoelectric material combining axion and dual axion responses. Our results establish intrinsic electromagnetic properties as a distinct class of material responses and show that scattering experiments alone are insufficient to characterize matter.
↳ physics.opticscond-mat.mes-hallhep-ph
23
Chaotic signatures in extreme-mass-ratio systems surrounded by bosonic environments
Qi-Xuan Xu · Kyriakos Destounis · Yin-Da Guo · Richard Brito · Taillte May
Extreme-mass-ratio inspirals are key gravitational-wave sources for testing strong gravity and the environments of massive black holes. While orbital motion in Kerr black hole spacetimes is integrable, realistic black holes may be surrounded by environments that break integrability. We investigate conservative orbital dynamics around rotating black holes surrounded by scalar clouds using fully nonlinear numerical solutions and an analytical post-Newtonian model. Poincaré sections and rotation curves reveal finite-width resonant islands, providing evidence for non-integrability even when the cloud carries only a small fraction of the black-hole mass. We show that the post-Newtonian description reproduces the dominant resonance and its island width for weak clouds, but underestimates the width in the configurations with stronger, more compact clouds examined here. Moreover, we find that for a scalar cloud as massive as the black hole, the phase space exhibits wider resonant islands as well as scattered layers indicative of chaotic motion. Together with earlier work, these results show that environmental effects can generically break the integrability of geodesic motion, motivating further study of resonance crossings and their gravitational-wave signatures once radiation reaction is included.
↳ gr-qcastro-ph.HEhep-ph
24
Non-linear electrodynamics emerging from a Lorentz-symmetry violation scenario
M. J. Neves · G. Peruzzo
The effective action at one-loop for the quantum electrodynamics (QED) in the presence of background vectors and tensors that break the Lorentz symmetry is calculated in this work. We highlight that just the Lorentz symmetry violation through the Dirac matrices in the fermionic sector is considered since investigations in others sectors of the extended QED has been explored in recent papers. Using the proper time method, we show that some background vectors and tensors do not contribute to the effective action at one-loop and in the linear approximation. Thereby, only two background tensors contribute to the effective action at one-loop for small components of these tensors, and that a new combination of cubic and quartic non-linear electrodynamics emerge in the weak field regime.
↳ hep-thhep-ph
25
Towards Precision-Controlled Partonic Structures from First Principles
Jinchen He
The internal structure of hadrons is governed by nonperturbative Quantum Chromodynamics (QCD). This dissertation presents first-principles calculations of partonic observables using lattice QCD and effective field theory, with controlled systematic uncertainties, advancing from collinear structure to transverse-momentum-dependent distributions (TMDs) that encode the three-dimensional partonic structure of hadrons. Within the large momentum effective theory (LaMET) framework, this work presents state-of-the-art calculations of pion distribution amplitudes and systematic studies of nucleon parton distributions, with control of renormalization, excited-state contamination, Fourier-transform systematics, and power corrections. A Coulomb-gauge formulation of quasi-distributions simplifies ultraviolet structure by avoiding Wilson-line related linear divergences, with Gribov-copy effects found to be negligible at current statistical precision. Building on these developments, this dissertation reports lattice determinations of nucleon TMD parton distributions, the Collins-Soper kernel, the intrinsic soft function, and pion TMD observables. These results provide nonperturbative inputs for global QCD analyses and the precision hadron-structure program, including the Electron-Ion Collider. In parallel, this work explores machine-learning acceleration of lattice gauge simulations through neural field transformations embedded in Hybrid Monte Carlo. In two-dimensional U(1) tests, the method reduces autocorrelation and improves performance toward finer lattice spacing, suggesting potential applications to more efficient lattice QCD simulations.
↳ hep-lathep-ph
26
Multi-Band Constraints on Cosmic Strings: Unifying Harmonic and Burst Spectra
Hansong Zhang · Huai-Ke Guo · Mairi Sakellariadou · Fengwei Yang · Yue Zhao
Cosmic-string loops generate a broadband gravitational-wave background (GWB) that is typically modeled via two distinct formalisms: a discrete harmonic expansion, commonly used in pulsar-timing-array (PTA) studies, and a continuous burst superposition, employed in ground-based GWB searches. In this work, we formally unify the two formalisms, showing that they provide discrete and continuous representations of the same underlying radiation process and converge on the scale-invariant spectrum plateau. On the rising low-frequency branch, where the first few harmonics dominate, the discrete nature becomes important, causing the two formalisms to diverge. Within this unified framework, the spectral calculation is more consistent across frequency bands, enabling multi-band inference. Leveraging this physical insight, we perform joint Bayesian inference across four representative loop-distribution models using the NANOGrav, EPTA, and LIGO--Virgo--KAGRA (LVK) datasets. By jointly sampling the string tension $G μ$ alongside the average cusp and kink numbers ${N_{c}, N_{k}}$ , the loop-radiation uncertainties are accounted for. We find that employing the harmonic expansion strengthens the LVK bounds by $21% - 31%$ for three of these models. Additionally, the stringent LVK bounds preclude three of these models from explaining the observed PTA common signal. For the sole surviving model, our multi-band analysis improves the inferred limit on $G μ$ .
↳ gr-qcastro-ph.COhep-ph
27
Distinguishing the origin of cosmic birefringence: dark energy, dark matter, and neutrino asymmetry
Lu Yin · Eiichiro Komatsu
Cosmic birefringence, the isotropic rotation of the plane of linear polarization of photons from sources at cosmological distances, can be generated by different parity-violating mechanisms. While the net rotation angle of a single polarized source carries little information about its physical origin, sources at various redshifts $z$ can be used to distinguish between different origins. Parity-sensitive correlations of the $E$ - and $B$ -mode polarization fields of the cosmic microwave background measured on large and small angular scales probe sources at $z ≃ 10$ and $1100$ , respectively. Thus, the detailed shape of the $E B$ power spectrum is sensitive to the redshift evolution of the birefringence source. In this paper, we calculate the $E B$ power spectrum due to a neutrino-asymmetry current, and compare it to axion dark energy and dark matter using a common Chern--Simons framework. We find that the $E B$ power spectrum due to a neutrino asymmetry is suppressed at low multipoles, $ℓ ≲ 20$ , similar to the dark matter case. This can be clearly distinguished from the dark energy case, which has no such suppression. Large-scale polarization measurements, including \textit{LiteBIRD}, can therefore distinguish late-time dark energy birefringence from that generated at higher redshifts by axion dark matter or neutrino asymmetry. We also find that the evolution of the neutrino density during recombination alters the shape of the $E B$ power spectrum at high multipoles. This signature can be used to distinguish between the neutrino and axion dark matter interpretations, using ground-based experiments such as the Simons Observatory.
↳ astro-ph.COastro-ph.HEhep-phhep-th
28
Entanglement-sensitive observables in $e^{+} e^{-} \to τ^{+} τ^{-}$ at STCF: a detector-level feasibility study
Chentao Bao · Xi Tao · Hai Chen · Lailin Xu · Xiaorong Zhou · Mingyi Liu
Quantum entanglement in $τ^{+} τ^{-}$ production provides a direct probe of non-classical spin correlations in a relativistic quantum system, with the $τ$ decay products serving as spin analyzers. We investigate the detector-level feasibility of such measurements in $e^{+} e^{-} \to τ^{+} τ^{-}$ at the Super Tau-Charm Facility (STCF) at $s = 7$ GeV, using the $ρρ$ and $π ρ$ decay channels. Signal and dominant background processes are simulated with the full STCF detector and reconstruction framework. Dedicated reconstruction and event-selection procedures yield overall signal efficiencies of approximately $4.5%$ and $4.8%$ , with corresponding purities of about $87.6%$ and $93.2%$ for the $ρρ$ and $π ρ$ channels, respectively. From the reconstructed decay kinematics, the $τ^{+} τ^{-}$ spin-density matrix is inferred and the concurrence $C [ρ]$ together with the Bell-sensitive quantity $m_{12} [C]$ are evaluated in a selected fiducial region. For the benchmark requirement $∣ cos θ ∣ < 0.2$ and an integrated luminosity of $1 ab^{- 1}$ , the projected relative precision on $C [ρ]$ is about $2.2%$ in both channels, while that on $m_{12} [C]$ is approximately $1.4%$ for $ρρ$ and $1.5%$ for $π ρ$ , including statistical and detector-resolution uncertainties. The reconstructed $m_{12} [C]$ shows a larger separation from its reference threshold in the $ρρ$ channel, making this topology particularly sensitive to Bell-type spin correlations. These results demonstrate the detector-level feasibility of probing quantum entanglement and non-classical spin correlations in hadronic $τ$ decays at STCF.
↳ hep-exhep-ph

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first authorsco-authorsvia INSPIRE