Mon·Jun 9, 2025Monday·June 9, 2025

1. 01*

   The $U(1{)}_{L_{\mu }-L_{\tau }}$ model meets the new $(g-2{)}_{\mu }$ data and muon neutrino trident scattering

   Ming-Wei Li🇨🇳 · Xiao-Gang He🇨🇳 · Andrew Cheek🇨🇳 · Xinhui Chu🇨🇳

   The Muon $g-2$ collaboration at Fermilab has announced their final result of the anomalous magnetic moment of the muon. By adopting the lattice-QCD evaluation of the leading-order hadronic-vacuum-polarization, this result is now in agreement with the latest theoretical prediction to the $1\sigma$ level. This new result further constrains the allowed parameter space, but does not rule out all possible new physics contributions the muon $g-2$. We study the implications for one of the relevant models, the gauged $U(1{)}_{L_{\mu }-L_{\tau }}$. When using this model to resolve the previous $4\sigma$ tension, results from muon neutrino trident (MNT) scattering experiments would restrict the mass of the new gauge boson ($Z^{\prime }$) to be less than $300$ MeV. Since the theory and experimental data difference for muon $g-2$ is lowered down to $1\sigma$, the requirement for $m_{Z^{\prime }}\lesssim 300\mathrm{MeV}$ is much relaxed. Within the updated allowed range of $Z^{\prime }$ boson mass, we study the models implications for electron and tauon $g-2$ as well as future muon colliders. We find that muon collider can effectively probe the $U(1{)}_{L_{\mu }-L_{\tau }}$.

   hep-phPLB(2025)·6 citations
2. 02*

   Models for differential cross section in proton-proton scattering and their implications at ISR and LHC energies

   Muhammad Saad Ashraf🇵🇰 · Nosheen Akbar🇵🇰 · Sarwat Zahra🇵🇰

   Few composite exponential models for the differential cross section are proposed to analyse the proton-proton ($pp$) elastic scattering at several energies. These proposed models are fitted to the data for $pp$ elastic differential cross section reported at CERN-ISR, LHC, and extrapolated energies of other models. These models have produced important features including dip-bump structure and shrinkage of the forward peak. Position of the dip is also well produced by our models for all the data across a broad energy range of $\sqrt{s}$ = 23 GeV, 23.5 GeV, 27.23 GeV, 30.7 GeV, 44.7 GeV, 52.8 GeV, 62.5 GeV, 200 GeV, 800 GeV, 2.76 TeV, 7 TeV, 8 TeV, 13 TeV, 14 TeV, 15 TeV, and 28 TeV. Employing these proposed models, elastic cross section, inelastic cross section, and total cross section are calculated at all the energies. Calculated results are compared with experimental data and theoretical results of other models. Implications of these results (obtained by models) related to the structure and dynamics of proton are discussed. The findings of this study emphasize the significance of combining theoretical and phenomenological approaches to accurately describe $pp$ elastic scattering at high energies and provide significant information to future LHC experiments for the investigation of differential cross section.

   hep-phEur.Phys.J.Plus(2025)·1 citation
3. 03*

   Quark-universal $U(1)$ breaking scalar at the LHC

   Lorin Armbruster🇩🇪 · Bogdan A. Dobrescu🇺🇸 · Felix Yu🇩🇪

   If the quarks or leptons are charged under a new $U(1)$ gauge symmetry, then besides a $Z^{\prime }$ boson there must exist at least one new boson whose decay products include Standard Model particles. In the case of a minimal symmetry breaking sector, that new boson is a scalar $\varphi$ that couples to the $Z^{\prime }$ boson as well as to the new fermions required to cancel the $U(1)$ gauge anomalies. The scalar may be produced at the LHC in association with a $Z^{\prime }$ boson, or through $Z^{\prime }$ boson fusion, while its decays are typically into four jets or two photons. We analyze in detail the case where the $Z^{\prime }$ boson is leptophobic, and all the quarks have the same charge under the new $U(1)$. If $\varphi$ mixes with the Standard Model Higgs boson, then the new scalar can also be produced via gluon fusion, and the discovery mode is likely to be a diphoton resonance.

   hep-phJHEP(2026)·2 citations
4. 04*

   Vector Boson Fusion Signatures of Superheavy Majorana Neutrinos at Muon Colliders

   Parham Dehghani🇨🇦 · Mariana Frank🇨🇦 · Benjamin Fuks🇫🇷

   We investigate the sensitivity of future high-energy muon colliders to heavy Majorana neutrinos, considering both opposite-sign (${\mu }^{+}{\mu }^{-}$) and same-sign (${\mu }^{+}{\mu }^{+}$) collision modes. We focus on ${\mu }^{+}{\mu }^{-}$ colliders operating at centre-of-mass energies of 1, 3 and 10 TeV, as well as the proposed $\mu$TRISTAN facility at 2 TeV, and we analyse the production of heavy neutrinos via vector boson fusion in the $t$-channel, a mechanism that becomes dominant in the multi-TeV regime. We evaluate its exclusion potential in terms of the heavy neutrino mass and the mixing of the heavy neutrino with its Standard Model counterparts, using both cut-based selections and boosted decision trees trained to exploit the distinct kinematic signatures of heavy Majorana neutrino exchanges. Our results demonstrate the complementarity between collider configurations, and show that active-sterile mixing angles as small as 0.001 could be probed for neutrino masses up to 100 TeV, an experimentally inaccessible region of the parameter space at current facilities. Altogether, this work establishes the discovery potential of muon colliders for testing super-heavy Majorana neutrinos, complementary to conventional probes, and provides compelling motivation for the next generation of high-energy lepton colliders.

   hep-phPRD(2025)·12 citations
5. 05*

   Accelerating multijet-merged event generation with neural network matrix element surrogates

   Tim Herrmann🇩🇪 · Timo Janßen🇩🇪 · Mathis Schenker🇩🇪 · Steffen Schumann🇩🇪 · Frank Siegert🇩🇪

   The efficient simulation of multijet final states presents a serious computational task for analyses of LHC data and will be even more so at the HL-LHC. We here discuss means to accelerate the generation of unweighted events based on a two-stage rejection-sampling algorithm that employs neural-network surrogates for unweighting the hard-process matrix elements. To this end, we generalise the previously proposed algorithm based on factorisation-aware neural networks to the case of multijet merging at tree-level accuracy. We thereby account for several non-trivial aspects of realistic event-simulation setups, including biased phase-space sampling, partial unweighting, and the mapping of partonic subprocesses. We apply our methods to the production of Z+jets final states at the HL-LHC using the Sherpa event generator, including matrix elements with up to six final-state partons. When using neural-network surrogates for the dominant Z+5 jets and Z+6 jets partonic processes, we find a reduction in the total event-generation time by more than a factor of 10 compared to baseline Sherpa.

   hep-phSciPost Phys.(2026)·17 citations
6. 06*

   Initial stage jet momentum broadening in tBLFQ formalism

   Dana Avramescu🇫🇮 · Carlos Lamas🇪🇸 · Tuomas Lappi🇫🇮 · Meijian Li🇪🇸 · Carlos A. Salgado🇪🇸

   We study the momentum broadening of a high-energy quark jet in the large density gluon medium created right after the collision of two ultrarelativistic heavy nuclei, the Glasma. Previous Glasma studies modeled the jet as a classical probe particle, for which position and momentum are simultaneously determined. In this work, we use the light-front QCD Hamiltonian formalism to treat the jet as a fully quantum state. We compute its real-time evolution while propagating through the Glasma classical background fields, which act as an interaction potential in the quantum evolution of the jet. We present results for the momentum broadening and jet quenching parameter of a jet at mid-rapidity, with special emphasis on the anisotropies between the longitudinal and transverse directions relative to the collision axis. In addition, we compare our results to classical calculations, and initiate a study of the distinction between kinetic and canonic momentum in the context of jet momentum broadening.

   hep-phnucl-thEPJ Web Conf.(2025)·3 citations
7. 07*

   Diffuse astrophysical neutrinos from dark matter around blazars

   Andrea Giovanni De Marchi🇮🇹 · Alessandro Granelli🇮🇹 · Jacopo Nava🇮🇹 · Filippo Sala🇮🇹

   Neutrinos from blazars can originate from inelastic scatterings between protons within their jets and sub-GeV dark matter (DM) around them, explaining IceCube detections of neutrinos from TXS 0506+056 that are otherwise challenging for models of its jet. In this paper we calculate such DM-induced high-energy neutrinos, from TXS 0506+056 as well as from a stacked blazar sample, in the four cases where DM-quark interactions are mediated by a new massive vector, axial, scalar, and pseudoscalar particle. Intriguingly, we find that this mechanism can saturate the diffuse astrophysical neutrino flux observed by IceCube at high energies. Our mechanism will be tested by additional blazar observations and by various searches for sub-GeV DM.

   hep-phastro-ph.HEPLB(2025)·12 citations
8. 08*

   Inequalities for Standard Model Yukawa Couplings

   Gero von Gersdorff🇧🇷 · Lucas Modesto🇧🇷

   We show that the Standard Model Yukawa matrices satisfy a set of simple yet nontrivial inequalities. The relations we derive are independent of the basis used to define the fermion fields, and, amongst other things, place strong constraints on the alignment of the columns of the up-type and down-type Yukawa matrices, as well as their cofactor matrices. The reason why one can obtain such strong statements can be traced back to the hierarchical nature of the fermion masses and quark mixings. The inequalities should be seen as very strong necessary conditions on the Standard Model Yukawa couplings and thus are useful for constraining flavor models.

   hep-phJHEP(2025)·3 citations
9. 09*

   Saving or Destroying the Universe with Axion-Like Particles

   Anne Mareike Galda🇩🇪 · Matthias Neubert🇺🇸

   Light pseudoscalar resonances that couple to the Standard Model via non-renormalizable operators, such as axions and axion-like particles (ALPs), generate contributions to the renormalization group evolution equations of couplings of dimension-4 and higher-dimensional operators. In particular, they modify the $\beta$-function of the Higgs quartic coupling and of SM and SMEFT parameters entering this equation, thus having an impact on the instability scale of the electroweak vacuum. We employ this fact together with the requirement that, in the presence of axions and ALPs, the Universe remains in a meta-stable state to deduce bounds on ALP couplings to the Standard Model fields. We also show that the modification of the $\beta$-functions of the gauge couplings by the ALP can lead to a unification around the Planck scale, even in non-sypersymmetric models.

   hep-ph2 citations
10. 10*

    Light Scalars in the Extended Georgi-Machacek Model

    Poulami Mondal🇮🇳 · Subrata Samanta🇮🇳

    We perform global fits of the CP-conserving Georgi-Machacek (GM) and extended Georgi-Machacek (eGM) models, incorporating a light CP-even beyond the Standard Model (BSM) scalar within the mass range of $90$ GeV to $100$ GeV. These fits combine the Higgs signal strengths and direct search limits from ATLAS and CMS at $\sqrt{s}=8$ and $13$ TeV, $B$-physics observables, and theoretical constraints arising from next-to-leading order (NLO) unitarity and BFB constraints. From the global fit, we show that the LHC diphoton and LEP $b\bar{b}$ excesses around $95$ GeV are well compatible with the $125$ GeV Higgs data. Whereas the CMS ditau excess is incompatible with the $125$ GeV Higgs signal strength data in both the CP-conserving GM and eGM models. We present the results from the combined fit, including the $95$ GeV Higgs signal strength data. In the eGM model, the triplet VEV cannot exceed $12$ GeV for additional BSM scalar masses below $160$ GeV and approximately $20$ GeV for additional BSM scalar masses above $160$ GeV. The masses of additional BSM scalars cannot exceed $600$ GeV. The maximum mass splitting is of around $120$ GeV within the members of each custodial multiplet, and up to $250$ GeV between the members of different multiplets. In the GM model, these constraints become more stringent: the triplet VEV is limited to below $15$ GeV, which tightens to $4$ GeV once the BSM scalar masses are below $160$ GeV. Masses of the quintet $m_5$ and the triplet $m_3$ are restricted to be below $530$ GeV and $320$ GeV, respectively. A mass hierarchy, $m_5>m_3$, is favoured in the high-mass region, with the mass splitting constrained to be less than $210$ GeV.

    hep-ph10 citations
11. 11*

    Freeze-in production of scalaron dark matter in $f(R)$ gravity

    Basabendu Barman🇮🇳 · Ashmita Das🇮🇳 · Rakesh Kumar SivaKumar🇮🇳 · Rudra Pratap Udgata🇮🇳

    We demonstrate that the scalaron, a scalar degree of freedom, emerging from the $f(R)$ theory of gravity, can account for the observed dark matter (DM) abundance if its mass is around the MeV scale, to ensure its cosmological stability. Focusing on two well-known $f(R)$ gravity models, we systematically show that if scalaron production proceeds via the freeze-in mechanism, the right relic abundance is satisfied over a very narrow window of reheating temperature $10^{14}\lesssim T_{\mathrm{rh}}\lesssim 10^{16}$ GeV. We delineate the viable parameter space of the $f(R)$ models consistent with the observed DM abundance, and highlight relevant experimental constraints from searches targeting DM decay signatures.

    hep-phastro-ph.COhep-thPRD(2026)·0 citations
12. 12*

    Data-Driven High-Dimensional Statistical Inference with Generative Models

    Oz Amram🇺🇸 · Manuel Szewc🇺🇸

    Crucial to many measurements at the LHC is the use of correlated multi-dimensional information to distinguish rare processes from large backgrounds, which is complicated by the poor modeling of many of the crucial backgrounds in Monte Carlo simulations. In this work, we introduce HI-SIGMA, a method to perform unbinned high-dimensional statistical inference with data-driven background distributions. In contradistinction to many applications of Simulation Based Inference in High Energy Physics, HI-SIGMA relies on generative ML models, rather than classifiers, to learn the signal and background distributions in the high-dimensional space. These ML models allow for interpretable inference while also incorporating model errors and other sources of systematic uncertainties. We showcase this methodology on a simplified version of a di-Higgs measurement in the $bb\gamma \gamma$ final state, where the di-photon resonance allows for background interpolation from sidebands into the signal region. We demonstrate that HI-SIGMA provides improved sensitivity as compared to standard classifier-based methods, and that systematic uncertainties can be straightforwardly incorporated by extending methods which have been used for histogram based analyses.

    hep-phhep-exstat.MLJHEP(2025)·4 citations
13. 13*

    Measuring spin correlation between quarks during QCD confinement

    The STAR Collaboration

    The vacuum is now understood to possess a rich and complex structure, characterized by fluctuating energy fields and a condensate of virtual quark-antiquark pairs. The spontaneous breaking of the approximate chiral symmetry, signaled by the nonvanishing quark condensate $⟨q\bar{q}⟩$, is dynamically generated through topologically nontrivial gauge configurations such as instantons. The precise mechanism linking the chiral symmetry breaking to the mass generation associated with quark confinement remains a profound open question in Quantum Chromodynamics (QCD) - the fundamental theory of strong interaction. High energy proton-proton collisions could liberate virtual quark-antiquark pairs from the vacuum that subsequently undergo confinement to form hadrons, whose properties could serve as probes into QCD confinement and the quark condensate. Here, we report evidence of spin correlations in $\Lambda \bar{\Lambda }$ hyperon pairs inherited from spin-correlated strange quark-antiquark virtual pairs. Measurements by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory reveal a relative polarization signal of $(18\pm 4)\%$ that links the virtual spin-correlated quark pairs from the QCD vacuum to their final-state hadron counterparts. Crucially, this correlation vanishes when the hyperon pairs are widely separated in angle, consistent with the decoherence of the quantum system. Our findings provide a new experimental paradigm for exploring the dynamics and interplay of quark confinement and entanglement.

    ↳ hep-exhep-phhep-thnucl-ex+1Nature(2026)·38 citations
14. 14*

    Pathfinding Quantum Simulations of Neutrinoless Double-Beta Decay

    Ivan A. Chernyshev🇺🇸 · Roland C. Farrell🇺🇸 · Marc Illa🇺🇸 · Martin J. Savage🇺🇸 · Andrii Maksymov🇺🇸 · Felix Tripier🇺🇸 · Miguel Angel Lopez-Ruiz🇺🇸 · Andrew Arrasmith🇺🇸 · Yvette de Sereville🇺🇸 · Aharon Brodutch🇺🇸 · Claudio Girotto🇺🇸 · Ananth Kaushik🇺🇸 · Martin Roetteler🇺🇸

    We present results from co-designed quantum simulations of the neutrinoless double-beta decay of a simple nucleus in 1+1D quantum chromodynamics using IonQ's Forte-generation trapped-ion quantum computers. Electrons, neutrinos, and up and down quarks are distributed across two lattice sites and mapped to 32 qubits, with an additional 4 qubits used for flag-based error mitigation. A four-fermion interaction is used to implement weak interactions, and lepton-number violation is induced by a neutrino Majorana mass. Quantum circuits that prepare the initial nucleus and time evolve with the Hamiltonian containing the strong and weak interactions are executed on IonQ Forte Enterprise. Enabled by tuned model parameters, lepton-number violation is observed in real time, providing a clear signal of neutrinoless double-beta decay. This was made possible by co-designing the simulation to maximally utilize the all-to-all connectivity and native gate-set available on IonQ's quantum computers. Quantum circuit compilation techniques and co-designed error-mitigation methods, informed from executing benchmarking circuits with up to 2,356 two-qubit gates, enabled observables to be extracted with high precision. We discuss the potential of future quantum simulations to provide yocto-second resolution of the reaction pathways in these, and other, nuclear processes.

    ↳ quant-phhep-lathep-phnucl-thNature Commun.(2026)·17 citations
15. 15*

    Detection of multiple X-ray quasi-periodic oscillations in IGR J19294+1816 with Insight-HXMT

    Wen Yang🇨🇳 · Wei Wang🇨🇳

    We report the timing results with Insight-HXMT observations of X-ray binary IGR J19294+1816 during its 2019 Type I outburst at the decline phase shortly following its peak. We analyze the light curves and power density spectrum (PDS) of the 2019 observations and reveal a peak at approximately ${\nu }_{NS}\sim 80.2$ mHz, corresponding to X-ray pulsations from the neutron star. In addition, a significant quasi-periodic oscillation (QPO) feature is observed at around ${\nu }_{QPO}\sim 30.2$ mHz from 10-50 keV, with the rms amplitude increasing with energy. Furthermore, we detect two QPOs at the frequency of $\sim 51.1$ mHz and $113.7$ mHz (corresponding to sidebands near ${\nu }_{NS}\pm {\nu }_{QPO}$) in 25-50 keV, exhibiting an rms amplitude of around 12$\%$. Wavelet analysis also shows multiple QPOs at the frequency of $\sim 30$ mHz, $50$ mHz and $110$ mHz and these QPO features show transient behaviors, the centroid frequencies of $\sim 30$ mHz remain nearly constant for different luminosities. Our research identifies IGR J19294+1816 as the second strong magnetic-field pulsar with significant sideband signals around the spin frequency. We explore various physical origins that could explain the presence of multiple QPOs.

    ↳ astro-ph.HEastro-ph.SRhep-phApJ(2025)·2 citations
16. 16*

    Smoking gun signature from axion and the constraints with radio telescopes

    Zixuan Liu🇨🇳 · Jiajun Zhang🇨🇳

    Axions are an elegant solution to the strong CP problem for particle physics and a promising dark matter candidate. They can convert into photons under a strong magnetic field, while magnetars with extreme magnetic fields are natural labs for axion detection. Radio telescopes can detect the radio emission from axion-photon conversion near magnetars. In this study, we have refined the calculation of axion-photon conversion and developed the matched filtering integration method to largely improve the signal-to-noise ratio. We validate our method using end-to-end simulation and real observational data from TMRT. A new constraint is set with only 687 seconds of observations with TMRT. Using 10 hours of observation with the high-frequency receiver in FAST or SKA, we can reach the theoretical coupling constant prediction for the axion mass range from 1$\mu$eV to 100$\mu$eV. We validate the possibility of axion detection with radio telescopes and avoid spectrum confusion.

    ↳ astro-ph.COhep-phPRD(2025)·1 citation
17. 17*

    Center vortices in the novel phase of staggered fermions

    Jackson A. Mickley🇦🇺 · Derek B. Leinweber🇦🇺 · Daniel Nogradi🇭🇺

    The geometry of center vortices is studied in the novel lattice-artefact phase that appears with staggered fermions to elucidate any insight provided by the center-vortex degrees of freedom. For various numbers of fermion flavors, the single-site shift symmetry of the staggered-fermion action is broken in a finite region of the $(\beta ,m)$ phase space. Simulations are performed with six degenerate fermion flavors and a range of $\beta$ values that span the phase boundary. Center vortices are demonstrated to capture the broken shift symmetry that manifests in the unphysical phase. This persists at the level of each individual plaquette orientation, where it is revealed that only the plaquettes that span the broken dimension are affected. Several bulk center-vortex quantities, including the vortex and branching point densities, are considered to highlight other aspects of vortex geometry sensitive to the unphysical phase. A slight preference for the plaquettes affected by the broken shift symmetry to be pierced by a vortex is observed. This translates also to a greater branching point density in three-dimensional slices that span the broken dimension. Combined, these findings provide a novel characterization of the unphysical phase in terms of the fundamental center degrees of freedom.

    ↳ hep-lathep-phhep-thnucl-thPRD(2025)·0 citations
18. 18*

    Femtoscopic signatures of unique nuclear structures in relativistic collisions

    Daniel Kincses🇭🇺

    One of the most vital topics of today's high-energy nuclear physics is the investigation of the nuclear structure of the collided nuclei. Recent studies at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) have shown that several observables, such as the collective flow and transverse-momentum correlations of the produced particles, can be sensitive to various nuclear structure and deformation parameters. Femtoscopy, another essential tool for investigating the space-time geometry of the matter created in nuclear collisions, has not yet been widely applied to such studies. Using a multiphase transport model (AMPT), in this Letter, it is demonstrated that the femtoscopic source parameters of pion pairs can also serve as a robust signal of unique nuclear structure. Through an analysis of ${}^{208}$Pb+${}^{20}$Ne and ${}^{208}$Pb+${}^{16}$O collisions at $\sqrt{s_{NN}}$ = 68.5 GeV, two collision systems especially relevant to the SMOG2 program of the LHCb experiment, it is shown that a deformed initial shape can significantly affect femtoscopic source parameters. This study highlights the importance of expanding the nuclear structure investigations to femtoscopic observables and serves as a baseline for numerous possible future studies in this new direction.

    ↳ nucl-thhep-phPRResearch(2025)·7 citations
19. 19*

    An Exploration of Vacuum-Decay Valleys

    J.R. Espinosa🇪🇸 · T. Konstandin🇩🇪

    In the standard lore the decay of the false vacuum of a single-field potential is described by a semi-classical Euclidean bounce configuration that can be found using overshoot/undershoot algorithms, and whose action suppresses exponentially the decay rate. While this is generically correct, we show in a few concrete examples of potentials, previously studied in the literature for other purposes, that the vacuum decay structure can be far richer. In some cases there is no bounce and decay proceeds via the so-called pseudo-bounce configurations. In the general case with bounce, there are $2n+1$ bounces, with $n$ ranging from 0 (the standard case) to $\infty$. Some of these decay configurations we call antibounces as they have the wrong behavior for overshoot/undershoot algorithms, which can miss them. Bounce and antibounce configurations form $n$ pairs connected by pseudo-bounces. Our analysis benefits from a combined use of Euclidean and tunneling potential methods.

    ↳ hep-thhep-phJCAP(2026)·4 citations
20. 20*

    Magnetogenesis from Sawtooth Coupling: Gravitational Wave Probe of Reheating

    Subhasis Maiti🇮🇳

    The detection of gravitational waves (GWs) by LIGO-Virgo and pulsar timing arrays (PTAs) has opened a new window into early universe cosmology. Yet, the origin of large-scale magnetic fields and the dynamics of the reheating epoch remain poorly understood. In this work, we study the generation of secondary GWs (SGWs) sourced by primordial magnetic fields produced via a Sawtooth-type coupling during reheating with a general background evolution. We show that the reheating equation of state significantly influences the spectral shape and amplitude of the magnetic fields. While a scale-invariant spectrum is typically needed to match observational bounds, this coupling naturally produces a strongly blue-tilted spectrum that remains consistent with current constraints. Crucially, the magnetic field continues to grow during reheating, leading to a GW signal with a broken power-law spectrum and a distinctive blue tilt on super-horizon scales. This SGW signal can fall within the sensitivity of upcoming detectors such as LISA, DECIGO, and BBO. The unique spectral features make this scenario distinguishable from other sources, offering a viable mechanism for cosmic magnetogenesis and a novel probe of the reheating era through GW observations.

    ↳ astro-ph.COhep-phPRD(2025)·6 citations
21. 21*

    Accurately simulating core-collapse self-interacting dark matter halos

    Moritz S. Fischer🇩🇪 · Hai-Bo Yu🇺🇸 · Klaus Dolag🇩🇪

    The properties of satellite halos provide a promising probe for dark matter (DM) physics. Observations have motivated current efforts to explain surprisingly compact DM halos. If DM is not collisionless, but has strong self-interactions, halos can undergo gravothermal collapse, leading to higher densities in the central region of the halo. However, it is challenging to model this collapse phase from first principles. To improve on this, we sought to better understand the numerical challenges and convergence properties of self-interacting dark matter (SIDM) N-body simulations in the collapse phase. Especially, our aim was to better understand the evolution of satellite halos. To do so, we ran SIDM N-body simulations of a low-mass halo in isolation and within an external gravitational potential. The simulation set-up was motivated by the perturber of the stellar stream GD-1. We find that the halo evolution is very sensitive to energy conservation errors, and a SIDM kernel size that is too large can artificially speed up the collapse. Moreover, we demonstrate that the King model can describe the density profile at small radii for the late stages that we have simulated. Furthermore, for our most highly resolved simulation (N = 5x10^7) we have made the data public. It can serve as a benchmark. Overall, we find that the current numerical methods do not suffer from convergence problems in the late collapse phase and provide guidance on how to choose numerical parameters, for example that the energy conservation error is better kept well below 1%. This allows simulations to be run of halos that become concentrated enough to explain observations of GD-1-like stellar streams or strong gravitational lensing systems.

    ↳ astro-ph.COastro-ph.GAhep-phAstron.Astrophys.(2025)·20 citations
22. 22*

    Regge trajectories, detectors, and distributions in the critical $\mathrm{O}(N)$ model

    Yue-Zhou Li🇺🇸 · David Simmons-Duffin🇺🇸

    We explore light-ray operators in the critical O$(N)$ model in the large-$N$ limit, focusing on leading-twist and leading ``horizontal" trajectories. We distinguish between light-ray operators in two conformal frames: detector operators, which characterize event shapes of final states, and distribution operators, which probe initial-state distributions. In particular, we identify parton distribution functions (PDFs) and collinear functions as matrix elements of appropriate distribution operators. We renormalize some simple detector operators at leading order in $1/N$, allowing us to extract the Regge intercept and the anomalous spin of the leading horizontal trajectory. We furthermore renormalize distribution versions of these operators, obtaining the leading-twist splitting function and a BFKL-type kernel, which match results from the detector frame. Finally, we show how these results can be read off from OPE data encoded in the Bethe-Salpeter resummation of conformal four-point functions.

    ↳ hep-thhep-phJHEP(2026)·13 citations
23. 23*

    Seeing through the confinement screen: DGLAP/BFKL mixing and light-ray matching in QCD

    Cyuan-Han Chang🇺🇸 · Hao Chen🇺🇸 · David Simmons-Duffin🇺🇸 · Hua Xing Zhu🇨🇳

    We argue that collider observables such as hadron number flux can be matched onto a linear combination of detectors/light-ray operators in perturbative QCD. The spectrum of detectors in QCD is subtle, due to recombination between the DGLAP and BFKL trajectories. We explain how to define and renormalize these trajectories at one-loop, systematically incorporating their recombination. The leading and subleading soft gluon theorems play an important role, and our analysis suggests the presence of an infinite series of further subleading soft theorems for squared-amplitudes/form factors. Combined with our light-ray matching hypothesis, the anomalous dimensions of recombined DGLAP/BFKL detectors yield a prediction for the energy dependence of the number of particles in a jet, as well as other predictions for more general energy-weighted hadron measurements. We compare these predictions to Monte-Carlo simulations, finding good agreement.

    ↳ hep-thhep-phJHEP(2026)·21 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.