HEP Phenomenology·hep-ph

Fri·Sep 4, 2026Friday·September 4, 2026

37 papers—25 primary·12 cross-listed

01
Finite-duration non-slow-roll effects in inflationary production of ultralight vector dark matter
Imtiaz Khan🇨🇳 · Niamat Ullah🇵🇰 · Chengxun Yuan🇨🇳 · G. Mustafa🇨🇳 · Farruh Atamurotov🇺🇿 · Ahmadjon Abdujabbarov🇨🇳
Inflationary production of ultralight vector dark matter can be amplified by a brief non-slow-roll phase, yet instantaneous mass transitions generate ultraviolet ringing and leave finite-time predictions unresolved. We replace the sharp transition with a smooth profile and derive the momentum-response kernel of the longitudinal mode. Finite duration preserves the infrared enhancement, suppresses modes that resolve the transition, and introduces a profile-dependent correction to the relic abundance. After fixing the dark matter abundance, the induced gravitational-wave signal retains an independent transverse-traceless source dependence, so abundance rescaling alone leaves residual profile information. Numerical mode evolution and radiation-era tensor integration support the finite-width treatment. Transition duration therefore links microscopic inflationary dynamics to ultralight vector abundance and its low-frequency gravitational-wave signal.
hep-ph0 citations
02
Resolving Local Structure of Distribution Functions in Collider Measurements
Cong Li🇨🇳
Collider measurements may blur narrow features in underlying distributions before fitting, since a data point samples a finite region. We show that observables linear in a selected target distribution, after externally constrained inputs are absorbed into a nonnegative finite response, have a calculable distribution-space locality set by hard dynamics and kinematics. The baseline-normalized $F_{dir} (X)$ yields the local value at zero width and a controlled average otherwise, with covariance setting the leading bias. This guides the choice of processes and observables that retain unexpected fine structure. An EIC photon-radiation observable realizes the exact zero-width limit.
hep-ph0 citations
03
Probing Quantum Foundations in Long-Baseline Neutrino Oscillations: Wave Packet Approach from MINOS Data to DUNE Predictions
Baktiar Wasir Farooq🇮🇳 · Bipin Singh Koranga🇮🇳 · Massimo Blasone🇮🇹
We investigate neutrino flavor oscillations in the wave packet formalism, extending the standard planewave treatment to incorporate the finite spatial coherence of neutrino mass eigenstates.We derive the full three flavor oscillation probability with MSW matter effects, decoherence, and localization suppression governed by the wave packet width, benchmarking against MINOS disappearance data and extending to DUNE predictions under the same parameters. To quantify how sharply the oscillation data constrain the wave packet width, we compute the classical Fisher information FC as a function of neutrino energy for both MINOS and DUNE, and show that its sensitivity is concentrated precisely in the low-energy regime where the wave-packet and plane-wave predictions diverge. Beyond the oscillation probability analysis, we compute wave particle entanglement complementarity quantities within a quantum information theoretic framework and explore the complete triality description involving entanglement, predictability, and visibility as functions of neutrino energy for both experiments such as MINOS and DUNE. We show that even when the oscillation probability is numerically indistinguishable from the planewave result, the wave packet structure leaves observable imprints in these triality measures. Our results demonstrate that the wave packet approach provides a theoretically consistent and experimentally motivated framework for probing quantum foundations in long-baseline atmospheric neutrino oscillation experiments.
hep-ph0 citations
04
Sub-TeV Singlino Dark Matter in light from Sagittarius A $^{*}$ and LUX-ZEPLIN Nuclear-Recoil Event
Utpal Chattopadhyay🇮🇳 · Debottam Das🇮🇳 · Rahul Puri🇮🇳 · Joydeep Roy🇮🇳
We investigate the impact of a dark matter density spike surrounding the Milky Way's supermassive black hole (SMBH) on the detectability of Singlino-dominated neutralino dark matter within the Next-to-Minimal Supersymmetric Standard Model (NMSSM). Similar density enhancements, or mini-spikes, around stellar-mass black holes (sBHs), have also been considered. Such a dark matter (DM) candidate typically produces weak indirect detection signals in conventional dark matter halos. Additionally, a Singlino-like lightest supersymmetric particle (LSP) is very difficult to probe at the LHC or through the direct DM search experiments. On top of that, recent observation of the LUX-ZEPLIN 248 keV Nuclear-Recoil Event may hint towards a DM that can be accommodated by a Singlino with mass more than 200 GeV. Keeping these in consideration, we examine the prospects for detecting these sub-TeV dark matter scenarios through gamma-ray observations of the regions surrounding the SMBH Sgr A $^{*}$ and the sBH in the low-mass X-ray binary XTE J1118+480.
hep-phastro-ph.HE15 citations
05
Yukawa coupling deviations from four-quark interactions
Sophie Renner🇬🇧 · Benjamin Smith🇬🇧
New physics generating four-quark interactions can be difficult to detect at the LHC, especially if it does not couple to first generation quarks. We investigate the possible role of such interactions in generating measurable deviations in Higgs-quark couplings. We find important constraints from flavour physics and top-pair production, but show that Higgs-charm and Higgs-bottom couplings remain the most sensitive LHC observables to some four-quark operators involving scalar currents. At FCC-ee, more operators and flavour structures can be tested. We further investigate simple single-particle models that can generate these interactions, including a second Higgs doublet, and scalar and vector diquarks. We find that in some cases, including new scalars most strongly coupled to the third generation of quarks, deviations in Yukawa couplings could offer the first signs of new physics generating four-quark interactions.
hep-ph0 citations
06
A Task Force on Strong Coupling Determinations from Event Shapes
Anthony Badea🇺🇸 · Luca Buonocore🇨🇭 · Gherardo Vita🇨🇭 · Simone Alioli🇮🇹 · Zeno Capatti🇨🇭 · Yi Chen🇺🇸 · David d'Enterria🇨🇭 · Thomas Gehrmann🇨🇭 · Andre H. Hoang🇦🇹 · Alexander Huss🇨🇭 · Sebastian Jaskiewicz🇨🇭 · Alexander Karlberg🇨🇭 and 10 other authors
The strong coupling constant $α_{s}$ is a fundamental parameter of the Standard Model. Its precise determination is essential for accurately predicting, studying, and understanding processes at the Large Hadron Collider and future experiments such as the Future Circular Collider. Event shape and correlator observables measured at electron-positron colliders provide one of the cleanest environments for extracting $α_{s}$ , thanks to their sensitivity to $α_{s}$ and the availability of high-precision data from the Large Electron-Positron Collider. More broadly, such observables provide an ideal setting to develop and test our understanding of the perturbative and non-perturbative elements of Quantum Chromodynamics, which will underpin the field's precision and discovery frontiers for decades to come. Despite these advances, significant discrepancies persist between different determinations of $α_{s}$ from event shapes, both in the extracted central values and estimated uncertainties. This document motivates the establishment of a dedicated Task Force to coordinate a community-wide effort addressing these open questions. We report on the first two-day meeting held at CERN in November 2025, summarizing the scientific discussion and documenting the experimental analyses identified as priorities during the meeting, as well as the concrete list of tasks to be carried out by the theory community in preparation for future meetings.
hep-phhep-ex0 citations
07
Strong Constraints on Line Signals from Dark Matter Annihilation in a Nearby Subhalo
Asier Salces Pérez🇪🇸 · Thong T.Q. Nguyen🇸🇪 · Pedro De la Torre Luque🇪🇸 · Tim Linden🇸🇪
We present a dedicated search for monochromatic gamma-ray emission from a recently proposed nearby dark matter subhalo candidate. Using nearly 15 years of Fermi-LAT Pass 8 data, we perform a sliding-window search for gamma-ray lines between 10 and 300 GeV. We do not find any statistically significant evidence for a line signal. The largest excess occurs at $E_{γ} ≃ 28 GeV$ with a local significance of $2.5 σ$ . We therefore derive 95% confidence level upper limits on the annihilation cross section for $χχ \to γ γ$ . Under the assumed NFW subhalo model, the resulting constraints are stronger than existing Galactic Center line limits over much of the explored mass range. We further translate these line constraints into bounds on well-motivated WIMP models, such as Higgs-portal and Wino dark matter scenarios, restricting previously open parameter regions consistent with thermal freeze-out as well as models associated with dark matter interpretations of the Galactic Center Excess.
hep-phastro-ph.HE0 citations
08
Energy-Energy Correlators in $Z$ -Tagged Jets in $pp$ Collisions
João Barata🇨🇭 · Zhong-Bo Kang🇺🇸 · Xoán Mayo López🇪🇸 · Jani Penttala🇺🇸 · Yiyu Zhou🇨🇳
We present predictions for the collinear energy-energy correlator (EEC) measured inside $Z$ -tagged jets in proton-proton collisions across the confinement transition. Our framework combines transverse-momentum-dependent factorization for back-to-back $Z +$ jet production with an exclusive differential EEC jet function incorporating perturbative evolution and flavor-dependent non-perturbative fragmentation. The EEC jet function is evaluated at $NLL^{'}$ accuracy, with separate quark and gluon non-perturbative scales constrained by existing $e^{+} e^{-}$ and inclusive-jet data. We provide predictions for forward $Z +$ jet production at $s = 8 TeV$ and $13 TeV$ in the jet transverse-momentum intervals $(20, 30)$ , $(30, 50)$ and $(50, 100) GeV$ . The EEC distributions as functions of $z_{χ}$ exhibit finite plateaus at small $z_{χ}$ , while the corresponding angular distributions display the characteristic turnover associated with the confinement transition. A flavor decomposition shows that this transition becomes increasingly dominated by quark-initiated jets as the jet transverse momentum increases. Forward $Z$ -tagged jets therefore provide a clean probe of non-perturbative quark fragmentation and offer a direct test of whether the characteristic confinement scale extracted from $e^{+} e^{-}$ collisions remains universal in a hadronic environment.
hep-phhep-ex0 citations
09
Quark Mixing Model with Three Higgs Doublets and $S_{3}$ Modular Symmetry at $τ = i$
Carlos Cerón🇲🇽 · Myriam Mondragón🇲🇽
We study the quark sector of a model with three Higgs electroweak doublets, complemented with a modular $S_{3}$ symmetry. We show that a proper assignment of the quark and Higgs fields in $S_{3}$ and their modular weights allows to write a mass matrix with a phenomenologically viable texture. Moreover, by considering the conditions on the Higgs VEVs derived from the minimization of the scalar potential together with evaluation of the Yukawa couplings at the fixed point $τ = i$ , leads to a significant reduction of the free parameters. We present two setups, one with three effective parameters, which is overly constrained, and one with four effective parameters, where the $V_{C K M}$ matrix can be fitted precisely.
hep-ph0 citations
10
Statistical Symmetry Breaking and Emergent Colored Noise in a Stochastic Scalar-Doublet Field Theory
Pei Wang🇨🇳
We investigate a relativistic stochastic field theory in which a complex scalar doublet is coupled to a complex white-noise source. The action preserves Lorentz and $U (1) \times SU (2)$ symmetries at the statistical level, whereas the corresponding Euler-Lagrange equations exhibit symmetry breaking along individual stochastic realizations. Within a gauge-field-free sector introduced to obtain analytical solutions, we show that the scalar doublet undergoes a noise-driven random walk in field space, leading to a finite, time-dependent ensemble average of its magnitude. As an illustrative application, we further investigate the coupling of the stochastic scalar field to fermions through a Yukawa interaction. The scalar-field solution naturally separates into a tail component, which contributes as an effective mass-like term, and a light-cone component, which acts as a colored-noise source that induces a spatially correlated stochastic phase in the fermion wave function. The statistical properties and correlation length of this emergent colored noise are derived analytically within the adopted approximations. The present work provides an exploratory study of statistical symmetry breaking and emergent colored-noise dynamics in a relativistic stochastic scalar-doublet field theory.
hep-phPhys.Scripta(2026)·0 citations
11
Leading-Neutron Electroproduction at HERA and the EIC: Sullivan Process, Target Fragmentation, and Pion PDFs
Wen-Chen Chang🇹🇼 · Chia-Yu Hsieh🇹🇼 · Satyajit Puhan🇹🇼
Leading-neutron electroproduction measurements from the H1 and ZEUS experiments at HERA have been used to constrain pion parton distribution functions (PDFs) at small momentum fractions within the Sullivan one-pion-exchange (OPE) framework, complementing large- $x_{π}$ constraints from pion-induced Drell--Yan measurements. Previous analyses have focused primarily on the region of large neutron longitudinal momentum fraction, $x_{L}$ , where contributions from deep-inelastic scattering (DIS) target fragmentation are suppressed. In this work, we use the \textsc{Pythia} event generator to model the target-fragmentation contribution and show that its combination with the OPE contribution reproduces the main features of the HERA leading-neutron data over the full measured $x_{L}$ range without introducing additional ad hoc normalization factors. This result demonstrates the potential of incorporating a broader range of leading-neutron data into future global analyses, thereby extending sensitivity to smaller pion momentum fractions $x_{π}$ . We investigate the model dependence associated with the pion--nucleon vertex form factor and show that the HERA data are sensitive to different target-fragmentation treatments implemented in \textsc{Pythia}. Finally, we present projections for leading-neutron production at the future U.S. Electron-Ion Collider (EIC), identifying beam-energy configurations and kinematic regions that provide enhanced sensitivity to pion structure while suppressing DIS target-fragmentation contributions.
hep-phhep-exnucl-ex0 citations
12
Meson mass spectrum in isospin QCD medium from the $N_{f} = 2 + 1$ quark-meson model
Yu-Han Gao🇨🇳 · Xu-Guang Huang🇨🇳 · Daiki Suenaga🇯🇵
We study phase structures, meson mass spectra, and sound velocities at finite temperature and density in QCD with isospin chemical potential ( $μ_{I}$ ). We employ the quark-meson model with $N_{f} = 2 + 1$ , incorporating the Kobayashi-Maskawa-'t Hooft type coupling to capture dynamical effects of the $U (1)_{A}$ axial anomaly. Within the mean-field approximation at quark one-loop, we analyze the onset of pion condensation, which manifests as a second-order phase transition at low temperatures and may exhibit a first-order behavior at higher temperatures within this approximation. We examine the corresponding mass spectra of scalar and pseudoscalar singlet-octet mesons, in which the $π_{+}$ mass is exactly massless in the superfluid phase due to its Nambu-Goldstone boson nature. The neutral pion mass is, meanwhile, found to exhibit a strictly linear growth with $μ_{I}$ in the pion condensed phase. We also investigate the isothermal squared sound velocity and identify characteristic structures associated with the phase transitions. Furthermore, we highlight how enhanced $U (1)_{A}$ anomaly effects facilitate the pion condensate to generate a less-pronounced sound velocity peak in cold medium. Our findings are expected to provide future lattice simulations with useful information on meson mass spectra from symmetry aspects.
hep-ph0 citations
13
Exploring millicharged particles in laboratory and astrophysical strong-field regimes
Cheng-Rui Jiang🇨🇳 · Tong Li🇨🇳 · Kai Ma🇨🇳 · Haolong Wang🇨🇳
The probe of light dark particles beyond the Standard Model (SM) under a strong-field environment has drawn significant attention. In this work, we investigate the potential to search for and constrain light millicharged particles (MCPs) via strong electromagnetic fields in both laboratory laser experiments and astrophysical environments such as magnetars. We propose the MCP pair production from nonlinear Compton scattering through the interaction of a relativistic electron beam with a high-intensity laser pulse. The Furry picture and Volkov solution of Dirac equation in a background electromagnetic field are used to describe the electrons and MCPs under an external classical laser field. We calculate the cross sections of nonlinear Compton scattering to MCP pairs and take into account the irreducible SM background with missing neutrinos. We also revisit the MCP pair production via the Schwinger mechanism from magnetars with ultra-strong magnetic field and parallel electric field in polar gap. The energy loss due to the Schwinger pair production of MCPs and electric field acceleration is evaluated based on Ruderman-Sutherland model for confirmed magnetars. We find that the constraints from highly magnetized magnetars and the search potential in laboratory laser experiments are complementary.
hep-ph0 citations
14
CGC-py: A Monte Carlo Event Generator for Gluon Saturation Physics
Haowu Duan🇨🇳 · Cong Yi🇨🇳 · Si-Wei Dai🇨🇳 · Shu-Yi Wei🇨🇳 · Wenbin Zhao🇨🇳 · Liang Zheng🇨🇳
We develop CGC-py, a Monte Carlo event generator for deep-inelastic scattering. It couples the full Color Glass Condensate (CGC) cross section for $γ^{*} p (A) \to q q ˉ + X$ to a Parton-Branching transverse-momentum-dependent backward initial-state shower, while \textsc{Pythia}~8 handles final-state radiation and hadronization. CGC-py retains the complete target-elastic and target-inelastic contributions without taking the back-to-back correlation limit, allowing single- and di-hadron observables to be generated consistently from the same event sample. We validate the generator through an analytic closure test of the single-inclusive quark spectrum and a comparison of charged-hadron spectra in $e p$ collisions with H1 data, finding excellent agreement. The predicted nuclear modification factor $R_{e Au}^{h}$ shows the expected saturation pattern: suppression at low $p_{T}^{*}$ followed by a rise toward unity at higher $p_{T}^{*}$ . A comparison with a \textsc{Pythia}~6 baseline, together with an $x_{g}$ -rescaling study, indicates that small- $x$ CGC evolution and collinear DGLAP dynamics contribute comparably to the growth of the dihadron away-side width with energy. Genuine saturation-driven broadening emerges only at the highest energies considered. Within CGC-py, $e Au$ collisions exhibit an enhanced away-side width and a suppressed back-to-back yield relative to $e p$ collisions. These nuclear effects remain modest over EIC kinematics, motivating measurements at the most forward accessible kinematics and the use of complementary observables to maximize sensitivity to gluon saturation.
hep-phhep-exnucl-exnucl-th1 citation
15
A Bayesian Pixel Based Approach for Model Independent TMD Reconstruction
Marco Zaccheddu🇺🇸
We introduce a nonparametric pixel-based framework for the Bayesian inference and imaging of transverse momentum dependent (TMD) parton distributions. The methodology integrates TMD evolution within the Collins-Soper-Sterman formalism in a differentiable framework, and leverages generative AI through a hybrid normalizing flow-driven Metropolis-Hastings algorithm for efficient posterior sampling. The framework is validated through multi-scale closure tests of increasing complexity. Using singular value decomposition, we characterize the existence of null TMDs, functional components that remain unconstrained by observables, and demonstrate how multi-scale data break these degeneracies, enabling 3D partonic imaging.
hep-ph0 citations
16
Light Leptoquarks in a Dark Sector: Scalar Dark Matter, Neutrino Mass, and Collider Signatures
Priyotosh Bandyopadhyay🇮🇳 · Kirtiman Ghosh🇮🇳 · Anirban Karan🇪🇸 · Snehashis Parashar🇮🇳 · Debabrata Sahoo🇮🇳
We investigate the dark matter (DM) phenomenology and subsequent collider signatures of a dark leptoquark (LQ) model containing dark vector-like quarks (VLQs) and a scalar singlet. The dark LQs and VLQs participate in the radiative generation of Majorana neutrino masses at one loop. Since the coloured LQs and VLQs cannot serve as viable DM candidates, a $Z_{2}$ -odd singlet scalar is introduced as the DM candidate. The $Z_{2}$ -odd nature of the LQs forbids their conventional decays into a quark and a lepton, allowing them to evade the standard LHC constraints that apply to visible LQ signatures. This framework therefore offers the distinctive possibility of sub-TeV dark LQs coexisting with TeV-scale dark VLQs. These sub-TeV dark LQs help in achieving the observed relic abundance of the singlet through co-annihilation. We analyse the resulting DM phenomenology and assess the prospects for probing this scenario at a future muon collider.
hep-ph0 citations
17
Probing the Geometry of Viable Froggatt-Nielsen-like Flavor Textures
Davide Meloni🇮🇹
We investigate the geometry of viable Froggatt--Nielsen-like flavor textures in a controlled toy landscape. In this first texture-level analysis, each point is represented by the eighteen integer exponents entering the up- and down-type Yukawa matrices, without imposing the additional charge-factorization constraints of specific Froggatt--Nielsen models. Viability is imposed through cuts on quark mass ratios and selected CKM observables. We construct four benchmark ensembles, ranging from masses-only constraints to the inclusion of the full set of CKM observables considered in this work, and study the resulting point clouds in the raw exponent space. Principal-component analysis shows no evidence for strong linear compression: in all benchmarks, fifteen principal components are required to account for 90% of the variance. Nearest-neighbour intrinsic-dimensionality diagnostics, including TwoNN and Levina--Bickel estimators, support the same qualitative conclusion, yielding high effective dimensions of order 10-12. These results do not rule out hidden flavor-theory geometry in other coordinates; rather, they suggest that raw Froggatt--Nielsen exponents may not provide natural coordinates for revealing such a geometry.
hep-ph0 citations
18
Exploring Extended Higgs Dynamics via Higgsstrahlung at FCC-ee
Anisha🇩🇪 · Francisco Arco🇩🇪 · Stefano Di Noi🇩🇪 · Christoph Englert🇬🇧 · Margarete Mühlleitner🇩🇪
The Future Circular Electron-Positron Collider (FCC-ee) will probe aspects of the Higgs boson and the electroweak scale with unprecedented precision via associated Higgs production with a $Z$ boson. We focus on the Two-Higgs-Doublet Model (2HDM) to frame the FCC-ee's precision constraints within a small, concrete parameter space at next-to-leading order. We demonstrate that the projected precision of the FCC-ee's 240 GeV run will enable a precise analysis of Beyond-the-Standard-Model (BSM)-relevant Higgs-sector interactions near the alignment limit. As the key aspects of the 2HDM that drive deviations of the cross section from its Standard Model expectation (presence of new scalar states, Higgs mixing, and non-trivial inter-Higgs couplings) are also typically present in extensions more complex than the 2HDM, this demonstrates the FCC-ee's indirect potential for unveiling BSM physics around the electroweak scale.
hep-ph0 citations
19
TQ4Q2.0 Fragmentation Functions for Fully Heavy Tetraquark Production
Francesco Giovanni Celiberto🇪🇸
We investigate the fragmentation dynamics underlying the production of fully heavy tetraquarks by means of the TQ4Q2.0 collinear FF set, covering scalar ( $0^{++}$ ), axial-vector ( $1^{+-}$ ), and tensor ( $2^{++}$ ) configurations. The fragmentation inputs are determined within NRQCD factorization for the complete set of relevant partonic channels and are subsequently evolved across heavy-flavor thresholds through the HF-NRevo scheme. Perturbative uncertainties associated with fragmentation-scale variations are consistently propagated together with nonperturbative effects encoded in color-composite long-distance matrix elements. Attention is devoted to the axial-vector sector, whose fragmentation pattern makes it especially sensitive to intrinsic-charm contributions at LHC and FCC energies. TQ4Q2.0 therefore provides an uncertainty-aware framework for exploring fully heavy tetraquark production over a broad kinematic range and for connecting exotic-hadron spectroscopy with the partonic structure of the proton.
hep-phhep-exnucl-exnucl-th0 citations
20
Inelastic Signatures of Electroweak Dark Matter
Juri Smirnov🇬🇧 · Spencer Griffith🇺🇸 · John F. Beacom🇺🇸
Minimal dark matter extended to include a Majorana and a Dirac multiplet coupled through the Higgs --- the HC-MDM model --- provides a compelling and predictive framework. We show that in certain limits of this model, the mass splitting and the inelastic interaction are representation-independent, while the thermal-relic masses are representation-dependent. We then show that this model can account for the high-energy recoil event recently reported by LUX-ZEPLIN (LZ) while also respecting thermal-relic, elastic-scattering, and solar-capture constraints. Generic inelastic DM models do not connect all these tests and generic Higgsino models do not survive them.
hep-phastro-ph.COhep-ex16 citations
21
TeV Higgsino Interpretation of the LZ High-Recoil Event with Intermediate-Scale Electroweak Gauginos
Xiaokang Du🇨🇳 · Fei Wang🇨🇳
The high-recoil event reported by LUX--ZEPLIN motivates a TeV Higgsino with a sub-MeV neutral-state splitting. Away from cancellations, such a small gap in the MSSM points to electroweak-gaugino masses of order $1 0^{7} GeV$ , far above the Higgsino mass. We show that the non-universal boundary condition $M_{1}^{G} / M_{2}^{G} = - 3/5$ at the $SU (5)$ GUT scale cancels the leading bino and wino contributions and is preserved by homogeneous one-loop evolution down to the Higgsino scale. The remaining finite-gaugino terms admit a controlled tree-level solution with a wino mass near $120 \TeV$ for a $350 \keV$ gap, a $1.091 \TeV$ Higgsino and $tan β = 10$ . We identify mixed $SU (5)$ representations that realize the required gaugino ratio and examine the radiative sensitivity and spectrum consistency of this construction. Because the inelastic $Z$ coupling remains essentially unsuppressed, a full-density thermal Higgsino is still subject to the published solar-capture bounds under their astrophysical and transport assumptions.
hep-ph16 citations
22
Confronting the Higgsino Interpretation of the LZ Event with the High-Energy Sideband
Nicholas L. Rodd🇺🇸 · Benjamin R. Safdi🇺🇸 · Tracy R. Slatyer🇺🇸 · Weishuang Linda Xu🇺🇸
The LZ experiment has reported a single 248 keV nuclear recoil event in their $2.84$ ton-yr exposure on a xenon target. The absence of lower nuclear recoil events is naturally explained by inelastically scattering dark matter (DM), for which the nuclear recoil energy spectra are shifted upwards from zero. Excitingly, the observed rate and spectra are consistent with a thermal $1.1$ TeV higgsino that explains all of DM with a mass splitting $δ \sim 370 - 490$ keV between the two lowest-lying Majorana states, with the range depending on the underlying DM velocity distribution. In this work, however, we show that higgsino DM with these properties would generically produce more higher-energy recoil events in a high-energy sideband along the LZ $S 1 c$ energy axis, while the LZ experiment reports no events in that bin. This suggests a possible tension which could be further explored by the LZ Collaboration, as the acceptance in that bin is not public. We further show that a non-thermal $\sim$ 500 GeV higgsino may evade the sideband constraint and that future experiments using heavy targets can potentially test the higgsino interpretation of the event either way.
hep-phastro-ph.CO17 citations
23
Seasonal dark matter from the LUX-ZEPLIN high-energy event
Christopher McCabe🇬🇧
The LUX-ZEPLIN experiment has reported a single nuclear recoil at $248 \pm 23 (stat) \pm 23 (sys) \keV$ in an extended search window. Inelastic dark matter, in which the scattering is endothermic, is a natural mechanism for producing a signal at such high energy. We fit the event to the dark matter mass and the mass splitting between two dark matter states, and find that the data favour a splitting pushed close to the kinematic limit set by the escape speed of the halo. The signal is then supplied by dark matter in the tail of the halo speed distribution. This drives a strongly seasonal signal: annual modulation rises above $50%$ across the favoured region of parameter space and even reaches $100%$ for some parameters, implying the signal vanishes for part of the year. Such a strong modulation distinguishes this interpretation sharply from a non-modulating signal, and we quantify the number of events needed to establish it. Experiments with larger target masses than LZ's, notably XLZD and PandaX, will be able to test this directly.
hep-ph15 citations
24
Atmospheric neutrino up-scattering explanation of LZ 2026 excess
Sk Jeesun🇨🇳 · Anirban Majumdar🇮🇳
The recent observation of an isolated nuclear recoil at $248 \pm 23 \pm 23$ keV energy by LUX-ZEPLIN (LZ) experiment has motivated the community to look for a new physics explanation, as the Standard model background estimation fails to accomodate that. Most of the existing literature hitherto considers a galactic halo dark matter with a heavier partner. In this work, we traverse the alternate route of atmospheric neutrino ( $ν$ ) up-scattering, thus producing a massive beyond standard model (BSM) particle $χ$ . The kinematic requirement of such a scattering poses a cut off in the lower recoil energies providing an explanation of the unique isolated event at such a higher recoil energy. Such up-scattering with the nucleons ( $\nuc$ ), $ν \nuc \to χ \nuc$ can be naturally realized in sterile neutrino models, though we keep our analysis generic without specifying $χ$ . We identify the region of parameter space that can produce such an isolated event assuming a scalar mediator with mass $m_{ϕ}$ and coupling $y_{χ, q}$ . For example, with $m_{χ} \sim 1$ GeV, and $y_{χ} y_{q} / m_{ϕ} = 2 \times 1 0^{- 2}$ GeV $^{- 1}$ can satisfy such an excess of events while remaining allowed by other existing constraints as well.
hep-phhep-ex15 citations
25
Axion Portal Dark Matter and the LUX-ZEPLIN High-Recoil Event
James Unwin🇺🇸
LUX-ZEPLIN (LZ) has reported one event compatible with a $248 keV$ nuclear recoil. While initial attention has focused on inelastic dark matter, that interpretation depends sensitively on the uncertain high-speed tail of the Galactic halo. We develop instead an elastic realization of the pseudoscalar-pseudoscalar interaction $L_{4} = (χ ˉ i γ^{5} χ) (N ˉ i γ^{5} N)$ , whose contact templates give one of the largest local significances identified by LZ. The minimal model presented involves primarily Dirac fermion dark matter, and a complex scalar leading to a pseudoscalar mediator. The minimal gauge-invariant UV completion also requires a single multi-TeV vector-like heavy quark. A representative model which realizes thermal freeze-out has $m_{χ} = 400 GeV$ and $m_{a} = 1 GeV$ . The simplest model breaks from the isoscalar/isovector assumption, and the response-level recoil spectrum lies between LZ's elastic $O_{4}^{v}$ and contact $L_{4}^{v}$ templates, suggesting a local significance of $2.6$ - $3.2 σ$ .
hep-ph14 citations
26
Observational constraints on Luciano-Saridakis holographic dark energy
Matías Leizerovich🇦🇷 · Susana J. Landau🇦🇷 · Giuseppe Gaetano Luciano🇪🇸 · Andreas Papatriantafyllou🇬🇷 · Emmanuel N. Saridakis🇬🇷
Holographic dark energy (HDE) models provide a natural framework for linking gravitational thermodynamics to the late-time accelerated expansion of the Universe. In this work, we investigate the observational viability of an extended HDE scenario arising from a recently proposed generalized entropy. For bounded systems, this entropy exhibits a generalized holographic scaling with two independent area contributions, giving rise to a modified HDE density that encompasses both standard HDE and $Λ$ CDM as limiting cases. Focusing on the Hubble-horizon infrared cutoff, we constrain the model using Cosmic Chronometers, the Pantheon $^{+}$ +SH0ES Type Ia supernova compilation, DESI DR2 baryon acoustic oscillations, and compressed Planck 2018 CMB shift parameters. We find that the model provides an excellent fit to the combined dataset and admits regions of parameter space in which the Pantheon $^{+}$ +SH0ES and CMB constraints can be simultaneously accommodated. The preferred solutions lie close to the $Λ$ CDM regime, although non-standard entropic contributions remain compatible with current observations. We further compare the complete realization of the model, containing both independent area contributions, with its reduced single-contribution limit, finding that both provide essentially equivalent descriptions of the data, with a mild preference for the latter. Our results establish generalized entropic HDE as a viable and theoretically motivated extension of the standard cosmological scenario and provide the first observational assessment of this cosmological framework.
↳ physics.gen-phhep-ph0 citations
27
Hadronic Mono-Z Dark Matter Sensitivity with Flow Matching on CMS Open Data
Hitesh Rasineni🇮🇳 · Bhavishya Chebrolu🇮🇳
We present a projected sensitivity study for hadronic mono- $Z$ dark-matter production using CMS Run~2015D HTMHT open data corresponding to 2.256382381~\invfb, from which 1{,}439{,}523 events satisfy the hadronic mono- $Z$ selection. Backgrounds are modelled with a conditional flow-matching continuous normalizing flow trained on the selected HTMHT events and evaluated on a held-out validation split reweighted to the full selected population. To mitigate artifacts from missing-object features and avoid in-sample scoring bias we apply sentinel imputation for undefined angular features, persist the train/validation split indices, and enforce a minimum reported background yield of 20 events when selecting the working point. A signal-side offline trigger proxy is applied to the simulated signal before scoring. Under this procedure the baseline analysis yields expected significances of 2.89 $σ$ , 7.62 $σ$ , and 7.41 $σ$ for three simplified-model benchmarks. An ablation study that removes the detailed extra-jet kinematics reduces the expected significance by 53--71\%, indicating that extra-jet topology carries substantial discriminating power in the hadronic mono- $Z$ channel. These results are projected sensitivities (no unblinding performed); the limitations and reproducibility of the study are discussed in Sections limitations and reproducibility.
↳ hep-excs.LGhep-phphysics.ins-det1 citation
28
Tidally-enhanced resonances in extreme-mass-ratio inspirals: A tertiary path to chaos
Kyriakos Destounis🇵🇹 · Takuya Katagiri🇮🇹 · Sajal Mukherjee🇮🇳 · Kostas D. Kokkotas🇩🇪
Extreme-mass-ratio inspirals (EMRIs) provide a unique laboratory for probing strong-field gravity and complex relativistic dynamics. We study a tidally deformed EMRI composed of a stellar-mass secondary orbiting a supermassive (non-)rotating black hole embedded in an external, adiabatically varying tidal environment. These systems provide a restricted, yet astrophysically motivated, realization of the relativistic three-body problem, expected to appear in active galactic nuclei, with a clear hierarchy of masses and radiation-reaction timescales. The external tidal deformation breaks the axisymmetry of the Kerr spacetime, rendering the geodesic dynamics non-integrable and giving rise to chaotic motion. The resulting signature of non-integrability is characterized through Poincaré maps and rotation curves constructed from the ratios of the fundamental frequencies of bound radial, polar, and azimuthal motion. We identify two prominent plateaus whose widths increase with the tidal field amplitude, signaling a transition from weak to strong chaos. We then demonstrate the sensitivity of the chaotic dynamics to the orientation of the orbit relative to the tidal field. We further analyze the proper-time evolution of the action-angle variables, showing that the angle combinations associated with the dominant commensurabilities are phase locked, thereby allowing the associated tidal contributions to induce secular changes in the constants of motion, whereas off-plateau angle combinations circulate. These results clarify the dynamical significance of the prominent plateaus and provide a novel phase-space characterization of tidal resonances in EMRIs. Finally, we discuss the potential role of radiation-reaction effects in driving EMRIs through tidal island crossings and the implications for gravitational-wave inference with future detectors.
↳ gr-qcastro-ph.HEhep-phhep-th+10 citations
29
Beyond isolated curvature peaks: collective collapse and multiple Primordial Black Hole formation
Albert Escrivà🇯🇵
Primordial black hole (PBH) calculations usually treat rare curvature peaks as isolated collapsing regions. Using fully nonlinear $3 + 1$ numerical-relativity simulations in a radiation-dominated Universe, we demonstrate that neighbouring primordial curvature perturbations need not map one-to-one onto PBHs: they may ultimately disperse, collapse collectively into a single PBH, or undergo distinct local collapses and form more than one PBH. In the family of two-component profiles studied here, the latter outcome is a pair of PBHs, identified by the coexistence of two disconnected apparent horizons on at least one time slice. We introduce a nonspherical quasi-local compaction diagnostic based on the Hawking mass and referenced to a round flat-FLRW sphere of equal area. It retains the angular structure of the curvature field and reduces to the standard Misner-Sharp compaction function in spherical symmetry. The global maximum of this diagnostic, $K_{form}$ , provides an empirical indicator of whether at least one PBH forms, with a transition near $K_{form, c} \approx 0.56$ and modest profile-dependent scatter. For forming bimodal profiles, we supplement the nonlinear compactness with a signed linear surface strength evaluated on the same probing spheres. The viability of the weaker local branch and the competition between the local and common-enclosing branches improve the empirical discrimination between single- and double-PBH outcomes. Our results therefore show that the maximum curvature amplitude alone does not determine the collapse outcome, which also depends on the spatial extent, characteristic scales, and geometry of the surrounding curvature environment.
↳ astro-ph.COgr-qchep-ph0 citations
30
Quantum Vacuum Nonlinearities in Laser Interferometers
Zain Mehdi · Joseph J. Hope · Simon A. Haine
We propose all-optical tests of photon-photon interactions in the matter vacuum using standing-wave laser interferometers, which do not require external magnetic fields and use conventional laser sources. We show that the interferometric detection of photon-photon scattering predicted by quantum electrodynamics is within reach of laboratory-scale experiments with a sensitivity that improves nonlinearly with the circulating power within the cavity. We outline how such an experiment could be adapted to probe properties of quantum fields beyond the Standard Model of particle physics.
↳ quant-phhep-ph0 citations
31
A Practical Partial-Wave Method for Identifying Unstable Light Nucleus Resonances in Heavy-Ion Collisions
Junlin Wu🇨🇳 · Hongchan Li🇨🇳 · Ke Mi🇨🇳 · Yaping Wang🇨🇳 · Guannan Xie🇨🇳
The production of light nuclei in relativistic heavy-ion collisions provides valuable insights into the dynamics of the hot and dense matter created in these extreme environments. While stable light nuclei have been extensively studied, unstable light nuclei being short-lived resonance states remain largely unexplored and offer unique opportunities to probe final-state interactions and the freeze-out conditions. In this paper, we propose a partial-wave method, based on the Lednický--Lyuboshitz framework, to extract resonance signals of unstable light nuclei from two-particle correlation functions measured in heavy-ion collisions. By extending the LL model to higher order partial waves and directly incorporating experimental phase-shift data from low-energy nuclear scattering, our approach avoids the need for model-dependent potential parametrizations and enables a clean decomposition of the resonant partial wave from the non-resonant background. As a demonstration, we apply the method to the $p$ - $^{3}$ He and $p$ - $^{4}$ He systems, corresponding to the $^{4}$ Li and $^{5}$ Li ground-state resonances. Numerical results show that the resonance-induced correlation excess can be effectively isolated, with a peak in the correlation function appearing at $k \approx 72$ MeV/ $c$ for $^{4}$ Li and $k \approx 50$ MeV/ $c$ for $^{5}$ Li, consistent with the known resonance parameters. The extracted transverse momentum spectra and rapidity distributions are presented using the measured proton and light-nuclei spectra from STAR at $s_{N N} = 3$ GeV. The proposed method provides a practical tool for the experimental study of unstable light nuclei in relativistic heavy-ion collisions and can be extended to a broader range of resonance states.
↳ nucl-thhep-ph0 citations
32
Ultra-compact twin stars with hybrid equations of state from bosonic dark matter
Ishfaq Ahmad Rather🇩🇪 · Sarah Louisa Pitz🇩🇪 · Jürgen Schaffner-Bielich🇩🇪
The properties of compact stars with a strong first-order phase transition to quark matter and with an additional fluid of self-interacting bosonic dark matter (DM) are studied. We find that the inclusion of DM changes considerably the stability of mass-radius configurations relative to the naive one-fluid criterion. For compact star configurations with similar masses and different radii, so-called twin stars, the presence of DM removes the unstable segment between the hadronic and the hybrid branch, so that the stable mass-radius sequence becomes continuous after the onset of the phase transition to quark matter. We furthermore find stable ultra-compact objects (UCOs), defined by a total compactness $C = M_{tot} / R_{grav} \geq 1/3$ . We observe two distinct classes of UCOs: a DM-halo class with $f_{DM} ≳ 0.9$ , and a DM-core class at $f_{DM} ≲ 0.02$ . The two classes can be separated by the surface redshift of the normal matter, which reaches $z = 0.73$ -- $0.77$ for the DM-core class and stays below $0.45$ for the DM-halo class. Finally, we find hybrid star solutions of 'ultimate twins' with similar mass and visible radius, but different dark matter content, leading to different tidal deformabilities and surface redshifts. Future X-ray and gravitational measurements of ultra-compact neutron stars with radii and masses outside the allowed neutron star range can thereby probe the presence and the properties of DM in addition to a first-order phase transition to quark matter.
↳ astro-ph.HEhep-phnucl-th0 citations
33
Cusped Defects: Cusp Operator Expansion, Conformal Properties and Bootstrap Applications
Lorenzo Bianchi🇮🇹 · Andrea Cavaglià🇮🇹 · A. David Gutiérrez🇮🇹 · Stefanos R. Kousvos🇮🇹 · Marco Meineri🇮🇹
We analyze general properties of cusped defect lines embedded in generic conformal field theories (CFTs). We prove that suitably defined cusp scaling operators transform like primary operators under general conformal transformations. We show that, via the cusp operator expansion (COE), defects of general shape can be expanded in a basis of cusped defects. These findings are checked and exemplified in the case of the localized magnetic field defect. Finally, we derive analytic constraints on dynamical cusp data by making use of a crossing equation, and discuss possible numerical bootstrap applications of our results.
↳ hep-thcond-mat.str-elhep-ph0 citations
34
Real-Time String Dynamics in $3 + 1$ D Lattice Quantum Electrodynamics
Helen Zwölfer🇩🇪 · Giovanni Cataldi🇩🇪 · Umberto Borla🇩🇪 · Jad C. Halimeh🇩🇪
Understanding real-time string dynamics in three spatial dimensions is essential for connecting quantum simulations of lattice gauge theories (LGTs) to the physical dimensionality of QED and QCD, where transverse fluctuations and competing local processes proliferate. We present the first real-time simulations of string breaking in $3 + 1$ D lattice quantum electrodynamics. Using tree tensor networks, we simulate the quench dynamics of electric flux strings in a $3 + 1$ D U(1) LGT with dynamical matter. At strong coupling, the string breaks resonantly at a sharp resonance condition of mass and gauge couplings, converting electric energy into matter--antimatter pairs that screen the static charges. Off resonance, we classify all competing channels---pair production, string deformations and extensions, and flux loops---whose multiplicity, extensive for pair production and flux loops, depletes the string sector even far from resonance. A channel-resolved perturbation theory quantitatively reproduces these dynamics and their Fourier spectrum. Our results establish diagnostics and benchmarks for upcoming quantum simulators of higher-dimensional LGTs.
↳ hep-latcond-mat.quant-gashep-phhep-th+10 citations
35
Non-Abelian string melting and thermalization in an open lattice gauge theory
Erick Parra Verde🇩🇪 · Giovanni Cataldi🇩🇪 · Stefan Kühn🇩🇪 · Giuseppe Magnifico🇮🇹 · Jad C. Halimeh🇩🇪
Open-system lattice gauge theory (LGT) has so far been developed predominantly in Abelian settings, leaving open how genuinely non-Abelian gauge structure reshapes dissipative real-time dynamics. Here, we study a $1 + 1$ D SU(2) Yang--Mills LGT with dynamical matter coupled to a thermal scalar environment through a gauge-preserving Lindblad evolution, which we solve using tensor networks. Starting from a quark--antiquark pair connected by a chromoelectric flux string, we find that the thermal medium melts the string by delocalizing the color charges and screening the flux; on resonance, this dissipative melting competes with and delays coherent string breaking. The thermalization time is non-monotonic in the environment coupling, decreasing through environment-assisted transport at weak dissipation before increasing in a quantum-Zeno regime. In the strong-dephasing limit, a Schrieffer--Wolff expansion maps the dynamics to a classical exclusion process and yields the Liouvillian thermalization time analytically. Beyond these generic open-system effects, the non-Abelian matter structure produces a systematic mesonic bias in the steady state, while the thermalization time decreases with temperature, in contrast to the Abelian Schwinger model trend and in qualitative agreement with pNRQCD studies of the quark--gluon plasma. These results establish a gauge-preserving framework for thermalization and string dynamics in open non-Abelian lattice gauge theories.
↳ hep-latcond-mat.quant-gascond-mat.stat-mechhep-ph+10 citations
36
Lattice QCD calculation of the pion-nucleon coupling $g ˉ_{0}$ induced by the QCD $Θ$ -term
Fangcheng He🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Rajan Gupta🇺🇸 · Emanuele Mereghetti🇺🇸
We present lattice QCD results for the CP violating pion-nucleon coupling $g ˉ_{0}$ induced by the QCD $Θ$ term from the analysis of three 2+1+1-flavor ensembles generated with highly improved staggered quarks (HISQ) by the MILC collaboration. These ensembles are at lattice spacing $a \approx 0.09 fm$ and pion masses of 313, 226 and 138 MeV, respectively. The coupling $g ˉ_{0}$ is extracted in two ways. First, from the matrix element of the correlation between the pesudoscalar current and the topological charge evaluated between the nucleon ground state. The data for correlation functions with both the pseudoscalar and axial vector exhibit large contamination from the $N π$ excited state. We show that these can be controlled at the leading order using chiral perturbation theory ( $χ$ PT) and the axial Ward identity (AWI, also called the partially conserved axial current (PCAC) relation). The result after removing the $N π$ contamination and extrapolating to the physical pion mass is, however, noisy: $g ˉ_{0} / (2 F_{π}) = - 7 (63) \times 1 0^{- 3} Θ$ . The more precise result $g ˉ_{0} / (2 F_{π}) = 17.4 (1.9) \times 1 0^{- 3} Θ$ is obtained using low energy effective field theory methods or equivalently the AWI. Since contamination from the $N π$ excited states arises in the calculation of many nucleon matrix elements, we give an extended discussion on them and the use of the AWI for controlling them in the calculation of $g ˉ_{0}$ .
↳ hep-lathep-ph0 citations
37
First Two-Hadron Form Factor from QCD
Felipe G. Ortega-Gama🇺🇸 · Raúl A. Briceño🇺🇸 · Ivan M. Burbano🇺🇸 · Robert G. Edwards🇺🇸
We present the first QCD determination of an energy-dependent form factor for a two-hadron scattering state. In particular, we calculate the QCD contribution to the forward electromagnetic $π^{+} π^{+} + γ \to π^{+} π^{+}$ amplitude at $m_{π} \approx 400$ ~MeV using lattice QCD. Because lattice calculations are performed in a finite Euclidean spacetime, where asymptotic scattering states are absent, this amplitude cannot be accessed directly from correlation functions. Instead, we can constrain this and related amplitudes nonperturbatively using a finite-volume formalism that requires two ingredients: the discrete finite-volume spectrum and finite-volume matrix elements of the electromagnetic current. We calculate three-point correlation functions coupling $π^{+} π^{+}$ finite-volume states and extract the corresponding electromagnetic matrix elements. Combining these results with the previously determined spectrum, we constrain the infinite-volume $π^{+} π^{+} + γ \to π^{+} π^{+}$ amplitude in the forward limit. Using constraints from Lorentz symmetry, unitarity, and analyticity, we describe this amplitude in terms of a single real-valued energy-dependent two-hadron form factor. The resulting amplitude and form factor agree with the Ward-Takahashi identity across all energies and moving frames considered, providing the first QCD validation of this finite-volume approach and a pathway toward first-principles studies of the electromagnetic structure and electroweak responses of resonances and multi-hadron bound states.
↳ hep-lathep-phnucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE