We investigate the quasinormal modes (QNMs) and greybody factors of dilaton–Euler–Heisenberg (dEH) de Sitter (dS) black holes in string-inspired Euler–Heisenberg gravity. Since the axial gravitational and electromagnetic perturbations decouple, we analyze them independently. By applying the asymptotic iteration method (AIM) together with a sixth-order WKB approximation, we compute the quasinormal frequencies and find excellent agreement between the two methods. We also find that the QNM spectra depend sensitively on the magnetic charge $Q_{\text{m}}$ , cosmological constant Λ, and nonlinear coupling $\epsilon$ , with a notable topological anomaly appearing in the electromagnetic frequency trajectories. Additionally, larger values of $Q_{\text{m}}$ or the multipole number $\textit{l}$ generally suppress wave transmission, while the electromagnetic sector with $\epsilon=1$ exhibits an anomalous response.

Ming Zhang

Guo-Xin Chen

China

Xufen Zhang

Cheng-Fu Feng

Sheng-Yuan Li

Rui-Hong Yue

De-Cheng Zou

Quasinormal frequencies and greybody factors for axial perturbations of dilaton–Euler–Heisenberg de Sitter black holes * This research was supported by the National Natural Science Foundation of China (NNSFC) (12365009), the Natural Science Basic Research Program of Shaanxi Province (2026JC-YBMS-0083), and the Jiangxi Provincial Natural Science Foundation (20262BAC240347)

The Standard Model of particle physics, although remarkably successful, leaves several major questions unanswered, continuing to motivate searches for new phenomena. Multiboson interactions involving the Higgs boson are of particular interest as probes of the electroweak Lagrangian, where potential new physics may reside. In this work, we present a study of the associated production of a $\textit{W}$ boson, a Higgs boson, and a photon in proton-proton collisions at the Large Hadron Collider (LHC). Monte Carlo simulations are performed to model both the signal and background processes, and detector effects are included according to CMS specifications. Boosted decision trees are employed to optimize the event selection and enhance signal–background discrimination. We estimate that, with an integrated luminosity of 440 fb$^{−1}$, the expected significance for the $WH\gamma$ process is 0.63$\textit{σ}$, increasing to a projected 1.64$\textit{σ}$ at the High-Luminosity LHC (HL-LHC).

Youpeng Wu

United Kingdom

Jie Xiao

Andrew Michael Levin

Qiang Li

Prospects for studying the $\textit{WHγ}$ process in $\textit{pp}$ collisions at the LHC * Supported in part by the National Natural Science Foundation of China (12325504, 12061141002)

We study the isospin-violating $J/\psi \to \Lambda\bar \Sigma^0 \eta $ reaction, recently measured by the BESIII collaboration, by considering the dominant terms involving $\bar \Sigma^0$ and pairs of pseudoscalar-baryon particles that together form an $\textit{SU}$(3) singlet and can therefore couple to the $J/\psi$ . We then allow these pairs to undergo final-state interaction to produce the final $\eta \Lambda$ . We find that the relevant original channels are $\bar K N$ and $K \Xi$ , and that the incomplete cancellation of terms involving charged and neutral particles, owing to their different masses, is responsible for the reaction. With this mechanism, we find good agreement with the three experimental mass distributions.

Spain

Lian-Rong Dai

Wen-Tao Lyu

E. Oset

Study of the $ {{\boldsymbol J}/\boldsymbol\psi\bf\to \boldsymbol\Lambda\bar{\boldsymbol\Sigma}^{\bf 0}\boldsymbol\eta}$ reaction * This work is partly supported by the National Natural Science Foundation of China (12575082). This work is partly supported by the National Key R&D Program of China (2024YFE0105200), the Natural Science Foundation of Henan (252300423951), the National Natural Science Foundation of China (12475086), and the Zhengzhou University Young Student Basic Research Projects for PhD students (ZDBJ202522). This work is also partly supported by the Spanish Ministerio de Economia y Competitividad (MINECO) and European FEDER funds (FIS2017-84038-C2-1-PB, PID2020-112777GB-I00), and Generalitat Valenciana (PROMETEO/2020/023). This project has received funding from the European Union Horizon 2020 research and innovation program (H2020-INFRAIA-2018-1, 824093 of the STRONG-2020 project)

In recent years, long-lived particles (LLPs) have attracted increasing attention in searches for physics beyond the Standard Model (SM). In this paper, we investigate the discovery prospects for light, long-lived ALPs predicted by the photophobic ALP scenario through displaced-vertex signals at the CEPC, with a center-of-mass energy of $ \sqrt{s}=91.2 $ GeV and an integrated luminosity of $ {\cal{L}}= $ 100 ab$^{−1}$. After comparing several possible single-production processes for the photophobic ALP, we focus on the dominant process $ e^+ e^- \to Z \to a \gamma $ , in which the ALP $\textit{a}$ subsequently decays into a pair of charged leptons at a displaced vertex. Dedicated Monte Carlo simulations are performed for the $ \mu^+ \mu^- \gamma $ and $ \tau_h^+ \tau_h^- \not{E}_T \gamma $ signals. For the $ \mu^+\mu^-\gamma $ signal, the CEPC is sensitive to the parameter region $ g_{aWW} \in [1.27\times10^{-3},6.80\times10^{-1}]\; {\rm{TeV}}^{-1} $ for $ m_a \in [1,4]\; {\rm{GeV}} $ . For the $ \tau_h^+\tau_h^-\not{E}_T\gamma $ signal, the accessible region is $ g_{aWW} \in [7.00\times10^{-4},9.40\times10^{-3}]\; {\rm{TeV}}^{-1} $ for $ m_a \in [4,9]\; {\rm{GeV}} $ . These results demonstrate the substantial potential of the CEPC to explore light, long-lived ALPs through displaced-vertex signals, providing complementary coverage to existing searches at LEP and the LHC, as well as to the projected reach of the HL-LHC.

Chong-Xing Yue

Xin-Yang Li

Prospects for probing light photophobic axion-like particles via displaced vertex signals at the CEPC * This work was partially supported by the National Natural Science Foundation of China (12575106) and the Cultivation Fund of Liaoning Normal University for Excellent Doctoral Dissertations (YJSYB202501)

We demonstrate that mass inequalities for hadrons containing one or more heavy quarks arise primarily from the concavity of binding energies in the quark model, reflecting short-range Coulombic interactions and long-range confinement. Empirical two-body bindings $ B_{i\bar{j}} $ are extracted from spin-averaged meson masses, ensuring model independence and direct use of experimental data. Fitting these quantities as functions of the reduced mass $ \mu_{ij} $ reveals a critical confinement scale of 1.34 fm, at which the bindings become positive. The concavity of $ B(1/\mu) $ motivates Jensen-like relations under flavor permutation, reproducing relations such as $ m_{x\bar{y}} \gt \dfrac{1}{2}(m_{x\bar{x}} + m_{y\bar{y}}) $ and the baryon analog $ m_{xyz} \gt \dfrac{1}{3}(m_{xxx} + m_{yyy} + m_{zzz}) $ . Hadron mass decomposition validates $ \Delta M_{ \rm{EXP}} \approx \Delta B + \Delta C $ with $ \sigma \sim 2.07 $ MeV for mesons and baryons. Using this decomposition, we obtain approximate mass estimates for unobserved heavy baryons (e.g., $ M(\Omega_{b}^{\ast})\approx 6076.6\, $ MeV, $ M(\Xi_{cc}^{\ast})\approx 3703.6\, $ MeV, and $ M(\Omega_{cc}^{\ast})\approx 3802.4\, $ MeV) and identify favored quark-exchange scattering channels. The present analysis is phenomenological and does not constitute a rigorous three-body derivation.

Wen-Xuan Zhang

Wen-Nian Liu

Duojie Jia

Mass relations in heavy hadrons from Jensen-like inequalities * Duojie Jia is supported by the National Natural Science Foundation of China (12165017)

The first evidence of electroweak (EW) production of pairs of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> bosons in association with two jets (jj) in the final state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>Z</mi><mi>Z</mi><mi>jj</mi><mo stretchy="false">→</mo><mo>ℓ</mo><mo>ℓ</mo><mi>ν</mi><mi>ν</mi><mi>jj</mi></mrow></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>ℓ</mo><mo>=</mo><mi>e</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi></mrow></math>, is reported by the CMS experiment. The analysis is based on a data sample of proton-proton (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math>) collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>138</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. Events are selected by requiring exactly two leptons of same flavor and opposite charge, large missing transverse momentum, and two jets with a large rapidity separation and large invariant mass. The EW production cross section in a fiducial volume is <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>EW</mi></mrow></msub><mo stretchy="false">(</mo><mi>p</mi><mi>p</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>Z</mi><mi>jj</mi><mo stretchy="false">→</mo><mo>ℓ</mo><mo>ℓ</mo><mi>ν</mi><mi>ν</mi><mi>jj</mi><mo stretchy="false">)</mo><mo>=</mo><mspace linebreak="goodbreak"></mspace><mn>0.3</mn><msubsup><mrow><mn>7</mn></mrow><mrow><mo>−</mo><mn>0.12</mn></mrow><mrow><mo>+</mo><mn>0.14</mn></mrow></msubsup><msubsup><mrow><mo stretchy="false">(</mo><mi>stat</mi><mo stretchy="false">)</mo></mrow><mrow><mo>−</mo><mn>0.06</mn></mrow><mrow><mo>+</mo><mn>0.06</mn></mrow></msubsup><mrow><mo stretchy="false">(</mo><mi>syst</mi><mo stretchy="false">)</mo></mrow><mtext> </mtext><mtext> </mtext><mi>fb</mi></mrow></math>, in agreement with the standard model prediction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>0.39</mn><mo>±</mo><mn>0.06</mn><mtext> </mtext><mtext> </mtext><mi>fb</mi></math>. The observed (expected) significance of the signal is 3.1 (2.8) standard deviations. Limits on anomalous quartic gauge couplings are derived in terms of dimension-8 effective field theory operators. A combination with the previously reported result from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi><mi>Z</mi></math> decay channel with four charged leptons yields an observed (expected) significance of 5.0 (4.5) standard deviations for the EW production of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson pairs.

Armenia

A. Gevorgyan

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

L. Benato

T. Bergauer

M. Dragicevic

S. Gundacker

A.K. Guven

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

M. Matthewman

J. Schieck

R. Schöfbeck

M. Shooshtari

M. Sonawane

N. Van Den Bossche

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

D. Ocampo Henao

T. Van Laer

P. Van Mechelen

D. Ahmadi

J. Bierkens

N. Breugelmans

S. Dansana

A. De Moor

M. Delcourt

S. Duponcheel

C. Gupta

F. Heyen

Y. Hong

K. Kang

P. Kashko

S. Lowette

I. Makarenko

S. Nandakumar

S. Tavernier

M. Tytgat

G.P. Van Onsem

S. Van Putte

T. Wybouw

A. Beshr

B. Bilin

F. Caviglia Roman

B. Clerbaux

A.K. Das

I. De Bruyn

G. De Lentdecker

E. Ducarme

H. Evard

L. Favart

I. Kalaitzidou

A. Khalilzadeh

A. Malara

A. Potrebko

M.A. Shahzad

L. Thomas

M. Vanden Bemden

C. Vander Velde

P. Vanlaer

C. Yuan

F. Zhang

A. Cauwels

M. De Coen

D. Dobur

C. Giordano

G. Gokbulut

K. Kaspar

D. Kavtaradze

D. Marckx

A. Mehta

K. Skovpen

A.M. Tomaru

J. van der Linden

J. Vandenbroeck

H. Aarup Petersen

A. Benecke

A. Bethani

G. Bruno

A. Cappati

J. De Favereau De Jeneret

C. Delaere

F. Gameiro Casalinho

A. Giammanco

A.O. Guzel

M. Hussain

Z. Lawrence

V. Lemaitre

J. Lidrych

P. Malek

S. Turkcapar

Brazil

G. Alves

M. Barroso Ferreira Filho

E. Coelho

Observation of Electroweak Production of Pairs of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> Bosons in Proton-Proton Collisions at 13 TeV

Quasiparton distribution functions (QPDFs) are defined in terms of QCD fields at spacelike separations evaluated in matrix elements of hadrons moving with velocity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>v</mi></mrow></math>. These objects can be studied in lattice QCD. In the limit when <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>v</mi></math> approaches the speed of light, QPDFs converge to parton distribution functions. It is insightful to study QPDFs and their convergence in models. In this work, we first study the QPDFs in a broad class of quark models characterized by one common feature, namely the absence of gauge degrees of freedom. We provide general proofs for the convergence and sum rules of the unpolarized quark and antiquark QPDFs for both choices <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>γ</mi><mn>0</mn></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>γ</mi><mn>3</mn></msup></math>. We choose the covariant parton model as an illustration, and derive analytical results for the small-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>x</mi><mi>v</mi></msub></math> behavior of QPDFs and the energy-momentum tensor form factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mi>q</mi></msup><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> at zero momentum transfer. These results are of interest as they correspond to a Wandzura-Wilczek-type approximation.

United States

F. Aslan

A. Tandogan

P. Schweitzer

Quasiparton distribution functions in covariant quark models

We systematically obtain all linear models which propagate a totally symmetric rank-three field without parity violation on a flat background. Each such model is defined exclusively by its gauge symmetry, which is usually a necessary property of effective field theories in the infrared limit. By comparison, models obtained by other means (tuning couplings and operators) may be unstable against radiative corrections. For each model, we compute the spectrum of massless and massive particles, and the no-ghost-no-tachyon constraints on the couplings. We conclude that foundational models exist which can propagate one massless particle of spin one or spin three in isolation, or both particles simultaneously, generalizing the model of Campoleoni and Francia. Our algorithm for detecting symmetric models is grounded in particle physics methods, being based directly on the Wigner decomposition of the field. Compared to our recent analysis of the totally symmetric rank-three field (whose results we confirm and extend) our new algorithm does not require an ansatz for the symmetry transformation, and is not restricted to so-called “free” symmetries.

Czechia

Will Barker

Estonia

Carlo Marzo

Chile

Alessandro Santoni

Infrared foundations for quantum geometry. I. Catalog of totally symmetric rank-three field theories

The construction of consistent effective field theories in the infrared suggests that models be defined by their underlying gauge symmetries, rather than by a tuning of couplings of operators which may not be stable against radiative corrections. Adhering to this principle, we systematically derive all linear, parity-conserving models that propagate a pair-antisymmetric rank-three field on a Minkowski background. Such models are relevant not only to torsion, but to many areas in high-energy physics ranging from dual graviton formulations to string theory and higher-spin theories. Starting from the general 12-parameter quadratic action, we obtain 206 gauge-symmetric specializations, of which 22 are free of ghosts and tachyons. Following this exhaustive classification, none of the unitary models are found to propagate scalar or pseudoscalar torsion, in stark contrast to the literature focus on spin-zero torsion. Instead, all models propagate one or more vector torsion modes.

Infrared foundations for quantum geometry. II. Catalog of all torsionlike theories including new ghost-tachyon-free cases

The relic abundance of thermal dark matter depends not only on its particle interactions but also on the expansion history of the early Universe. We study the freeze-out of fermionic dark matter interacting with the Standard Model through higher-dimensional electromagnetic operators in an early matter-dominated cosmology. In particular, we consider magnetic-dipole, electric-dipole, anapole, and charge-radius interactions and compute the interaction strengths required to reproduce the observed dark matter relic abundance, accounting for the subsequent entropy injection from the decay of a long-lived heavy field. We compare the resulting parameter space with that obtained in the standard radiation-dominated freeze-out scenario and confront it with current constraints from direct-detection experiments and solar-neutrino searches. We find that the entropy dilution associated with an early matter-dominated epoch significantly reduces the interaction strength required to obtain the observed relic abundance, thereby opening regions of parameter space that are excluded within the conventional cosmological history.