We extend the hidden zeros and 2-split of tree-level Tr($\textit{ϕ}$ ) amplitudes to loop-level Feynman integrands, apart from some physically irrelevant scaleless integrals. Our method is based on a certain factorization mechanism that occurs in Feynman diagrams when summing over shuffle permutations. The loop-level hidden zeros and 2-split identified in this work differ from those in the literature. In our result, the kinematic conditions for loop-level hidden zeros and 2-split are remarkably simple. Their connection is as tight as at tree-level, with the same procedure for obtaining the 2-split condition from the zero condition. The resulting 2-split formula at loop-level represents a generalization of that at tree-level: the $\textit{L}$-loop integrand is expressed as a sum over $\textit{L}$ + 1 terms, each of which exhibits a 2-split structure.

China

Kang Zhou

Towards new hidden zero and 2-split of loop-level Feynman yntegrands in Tr($\textit{ϕ}$ 3) model

Precision Higgs physics offers a sensitive window into physics beyond the Standard Model. In parallel, neutrino-oscillation experiments have established the existence of nonzero neutrino masses, thus implying the presence of new physics. Motivated by these facts, we investigate the one-loop contributions of light and heavy Majorana neutrinos to the $\textit{ZZh}$ vertex within a variant of the type-I seesaw mechanism in which light-neutrino masses vanish at tree level and are then generated radiatively. We analyze the $\textit{CP}$ -conserving and $\textit{CP}$ -violating anomalous couplings which characterize the $\textit{ZZh}$ vertex and study their phenomenological implications in two relevant kinematic scenarios at future lepton colliders: Higgsstrahlung production and Higgs production via neutral-current vector-boson fusion. We find that $\textit{CP}$ -conserving effects can reach magnitudes of order 10 , potentially within projected future experimental sensitivities, whereas $\textit{CP}$ -violating contributions are strongly suppressed, lying well beyond such projections.

Mexico

Héctor Novales-Sánchez

Humberto Vázquez-Castro

Mónica Salinas

New physics in the $\textit{ZZh}$ vertex: one-loop contributions from a radiative seesaw model

We present an investigation of the $ K^*(1680) $ state in its strong decays into two-body final states within the flux-tube model and quark pair creation model. Since charge conjugation parity is not conserved in the strange sector, the conventional $ q\bar{q} $ states with $ J^{P(C)}=1^{-(-)} $ can mix with the lowest hybrid states with $ J^{P(C)}=1^{-(+)} $ . Our analysis of the $ K^*(1680) $ two-body strong decays indicates that the decay pattern of $ K^*(1680) $ cannot be explained by the conventional $ q\bar{q} $ scenario. Moreover, there is strong evidence for the $ q\bar{q} $ -hybrid mixing mechanism in the strange sector. The phenomenological consequences of such mixing are also discussed. Our study can provide guidance for future searches for hybrid multiplets in experiments at BESIII, LHCb, and Belle II.

Samee Ullah

Ye Cao

Ming-Xiao Duan

Hai-Bing Fu

Qiang Zhao

Nature of ${K^*(1680)}$ and ${q\bar{q}}$ -hybrid mixing as the $\textit{SU}$(3) partner of ${\eta_{1}(1855)}$ in the strange sector * Supported in part by the National Natural Science Foundation of China (12235018, 12265010, 12505098), and the Project of Guizhou Provincial Department of Science and Technology (MS[2025]219, CXTD[2025]030, ZD[2026]168, QN[2025]178), and the project of Guizhou Normal University (GZNUD[2025]05)

The triangle singularity interpretation of the $a_1(1420)$ observed by the COMPASS Collaboration has been widely accepted. In this work, we investigate the triangle mechanism in the decay $B^0 \to D^- \pi^+ a_0(980)(\pi^0 \eta)$ , where the $a_0(980)$ is treated as a dynamically generated state. The $\bar{K}^{*0}$ - $K^+$ - $K^-$ triangle loop originates from the decay $B^0 \to D^- K^+ \bar{K}^{*0}$ , which has been observed by the Belle Collaboration, followed by the subsequent decay $\bar{K}^{*0} \to K^- \pi^+$ . The triangle amplitude develops a pronounced peak around 1420 MeV, which is reflected in the invariant mass spectrum of the $\pi a_0(980)$ system. The differential decay width is calculated and exhibits a narrow peak around $980~\mathrm{MeV}$ in the $\pi^0 \eta$ invariant mass distribution. Furthermore, the invariant mass distribution of the $\pi^+ \pi^0 \eta$ system shows a clear peak around $1420~\mathrm{MeV}$ , which further confirms the triangle singularity explanation of the $a_1(1420)$ . We expect that the proposed $B^0$ decay mode could provide a potential platform for further exploring the triangle-singularity nature of the $a_1(1420)$ and could be tested in future experiments such as LHCb, BESIII, and Belle II.

Wei Wang

Dazhuang He

Xuan Luo

The role of triangle singularity in the $ {B^0 \to D^- \pi^+ a_0(980)(\pi^0 \eta)}$ decay * Dazhuang He is supported by the Heze University doctoral fund project (010008002039037). Xuan Luo is supported by the National Natural Science Foundation of China (12205002)

We demonstrate that at finite density and sufficiently high temperatures, phase-quenched (PQ) lattice simulations combined with perturbation theory provide a new precision approach to determining the thermodynamics of QCD across a wide arc of the phase diagram where the strong coupling constant <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mi>s</mi></msub></math> remains small. In this regime, nonperturbative pairing effects in the PQ theory are parametrically suppressed, so that the difference between the PQ and full QCD pressures becomes a small perturbative correction. We compute this correction up to and including <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>O</mi><mo stretchy="false">(</mo><msubsup><mi>α</mi><mi>s</mi><mrow><mn>7</mn><mo>/</mo><mn>2</mn></mrow></msubsup><mo stretchy="false">)</mo></math> using electrostatic QCD together with a novel numerical method to compute four-loop sum-integrals. This enables the determination of the perturbative QCD pressure with precision beyond the current state of the art while including nonperturbative pure-gluonic contributions from the lattice.

United States

Tyler Gorda

Finland

Pablo Navarrete

Risto Paatelainen

Leon Sandbote

Switzerland

Kaapo Seppänen

New approach to determine the thermodynamics of deconfined matter to high accuracy

We analyze the potential of the Universal SMEFT as a tool to study universal new physics in the neutral and charged Drell-Yan processes at the high-luminosity LHC. In order to do so, we generated pseudodata containing the contributions of beyond the standard model vector bosons to the dilepton production. Our results show that fits with the minimal theoretical bias can be used not only to unveil the existence of new physics but also to accurately extract its properties. Moreover, the results are rather stable with respect to the order of truncation of the effective field theory.

Austria

Tyler Corbett

Jay Desai

Brazil

O.J.P. Éboli

Spain

M.C. Gonzalez-Garcia

Matheus Martines

Universal SMEFT as a tool for discovery of universal new physics at the high luminosity LHC

Global analysis of neutrino oscillation data slightly favors normal mass ordering. In this work, we investigate an extended scalar sector that naturally gives rise to a type I + II seesaw mechanism after spontaneous symmetry breaking and explore the interplay between collider physics and lepton flavor violation, adopting normal ordering. In particular, we focus on the rare muon decays $$\mu \rightarrow e \gamma $$ and $$\mu \rightarrow 3e$$ and the same-sign dilepton searches at LHC, a canonical signature of a doubly charged scalar. We conclude that neither the precise value of the sum of the neutrino masses, taken from DESI data that favors $$\sum m_\nu =0.07$$ eV, nor alternative cosmological fits which prefer a more relaxed limit $$\sum m_\nu =0.1$$ eV, significantly changes the theoretical prediction for these rare decays. However, we observe an interesting interplay between collider physics and lepton flavor violation. In particular, we find that $$\mu \rightarrow 3e$$ is more constraining than $$\mu \rightarrow e\gamma $$ . The $$\mu \rightarrow 3e$$ decay can yield a lower mass limit of 3 TeV on the doubly charged scalar, surpassing current LHC constraints in a dominant type II seesaw or in a mixed type I+II scenario. Nevertheless, LFV does not strongly constrain the dominant type I seesaw scenario.

Maria Aguilar

Chile

Juan Helo

Toshihiko Ota

Farinaldo Queiroz

David Suarez

Amanda Rodríguez

Type I + II seesaw model in light of the new neutrino oscillation measurements

We derive new families of quantum null energy inequalities (QNEIs), i.e. bounds on integrated null energy, in quantum field theories in two and higher dimensions. These are universal, state-independent lower bounds on semi-local integrals of 〈$\textit{T}$ 〉, the energy-momentum flux in a null direction, and the first of this kind for interacting theories in higher dimensions. Our ingredients include the quantum null energy condition (QNEC), strong subadditivity of von Neumann entropies, defect operator expansions, and the vacuum modular Hamiltonians of null intervals and strips. These results are fundamental constraints on null energy in quantum field theories.

United Kingdom

Belgium

Jackson Fliss

Andrew Rolph

Curious QNEIs from QNEC: new bounds on null energy in quantum field theory

We investigate the sensitivity of the Electron-Ion Collider (EIC) to invisible final states in coherent exclusive electroproduction. The characteristic signal is a forward proton with reduced energy and little additional detector activity. Using the excellent particle detection capabilities and kinematics reconstruction at the EIC, we argue that backgrounds can be strongly suppressed. While our analysis applies to various states, we specifically focus on vector and pseudoscalar particles: (i) neutral mesons [<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi><mo>=</mo><msup><mi>π</mi><mn>0</mn></msup><mo>,</mo><msup><mi>η</mi><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msup><mo>,</mo><mi>V</mi><mo>=</mo><msup><mi>ρ</mi><mn>0</mn></msup><mo>,</mo><mi>ω</mi><mo>,</mo><mi>ϕ</mi></math>], whose invisible standard model decays are extremely suppressed, and (ii) gluon-coupled axionlike particles (ALPs) decaying invisibly to a dark sector. With the baseline detector and a conservative residual-background estimate, the EIC can improve the sensitivity to invisible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>η</mi><mo>′</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ω</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi></math> decays by factors of about 4–40 and probe invisible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ρ</mi><mn>0</mn></msup></math> decays for the first time. With further background reduction and optimized detector performance, the projected sensitivity may reach branching fractions as small as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup></math>. In addition, under the same conditions, the EIC would directly probe invisibly decaying ALPs with the couplings up to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>∼</mo><msup><mn>10</mn><mn>5</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> and masses in the range 0.1–2 GeV.

Reuven Balkin

Israel

Ta’el Coren

Alexander Jentsch

Hongkai Liu

CERN

Maksym Ovchynnikov

Yotam Soreq

Sokratis Trifinopoulos

Braking Protons at the Electron-Ion Collider: From Invisible Meson Decay to New Physics Searches

Traditional direct detection experiments lack the sensitivity to probe the sub-GeV dark matter(DM), primarily due to the low energy of the expected nuclear recoils. In this work, we investigate cosmic-ray (CR) upscattering as a mechanism to accelerate DM particles to detectable velocities in underground experiments. By analyzing four models of DM-nucleon interactions – namely scalar, vector, pseudoscalar, and axial-vector mediators – we derive constraints on the coupling parameters using data from the LZ, XENON, and Borexino experiments, covering mediator mass from $$10^{-6}$$ to 1 GeV. As the mediator mass varies, the shift in dominance between momentum transfer and mediator mass leads to a turnover in the constraints around $$10^{-2}$$ – $$10^{-3}~\textrm{GeV}$$ . Our results extend the reach of direct detection into the sub-GeV window and clarify the critical role of momentum dependence in light-mediator scenarios.