We constructed a four-Higgs-doublet model (4HDM) invariant under $\textit{D}$ $_{5}$ symmetry and investigated its complete neutral vacuum structure in detail. Assuming explicit CP conservation in the scalar potential, we examined whether CP symmetry can be spontaneously broken. We provided a complete list of all possible real and complex vacua, along with the constraints on the potential parameters required for each vacuum solution to exist. We also discussed the positive-definiteness conditions that the Hessian must satisfy for each vacuum to be a local minimum of the potential. The results show that, after spontaneous symmetry breaking, some complex vacua lead to spontaneous CP violation in the potential, whereas the remaining complex vacua still preserve CP conservation. Among these CP-violating complex vacua, one can be regarded as the most general form. Furthermore, we discussed the relationship between real and complex vacua.

China

Dong-Ping Fu

Michihisa Takeuchi

Spontaneous CP violation in the $\textit{D}$ $_{5}$-symmetric four-Higgs-doublet models * Supported by the Fundamental Research Funds for the Central Universities, the One Hundred Talent Program of Sun Yat-sen University, China, and the Guangdong Natural Science Foundation (2026A1515012641)

Hadron-hadron interactions, being nonperturbative in nature, play a significant role in addressing phenomenological questions in particle physics. Femtoscopy is a powerful tool in heavy-ion collision experiments, enabling the extraction of hadron-hadron interactions via momentum-correlation functions (CFs). These CFs are typically expressed as a convolution of source functions and hadron-hadron wave functions, with the latter encoding information about the interactions. However, source functions remain poorly constrained and are commonly approximated by a Gaussian form. Reconstructing source functions from experimental correlation data constitutes an 'inverse problem.' To address this, we propose a toy model based on Tikhonov regularization. Using a square-well potential with four distinct strengths, we calculate the CFs for inputs of single Gaussian source functions and mixed Gaussian source functions. The resulting CFs are then used to reconstruct the source functions via Tikhonov regularization. Our results show that the Gaussian source function can be successfully reconstructed, highlighting the potential of this approach for extracting realistic source functions from hadron pairs of interest.

Ao-Sheng Xiong

Qi-Wei Yuan

Ming-Zhu Liu

Fu-Sheng Yu

Zhi-Wei Liu

Li-Sheng Geng

Solving the inverse source problem in femtoscopy with a toy model * Supported in part by the Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of China (JYB2025XDXM204) and the National Natural Science Foundation of China (W2543006, 12435007). Ming-Zhu Liu acknowledges support from the National Natural Science Foundation of China (12575086). Zhi-Wei Liu acknowledges support from the National Natural Science Foundation of China (12405133) and from the Shenzhen Science and Technology Program (ZDSYS20230626091501002). Fu-Sheng Yu and Ao-Sheng Xiong acknowledge support from the Scientific Research Innovation Capability Support Project for Young Faculty (ZYGXQNJSKYCXNLZCXM-P2) and from the Fundamental Research Funds for the Central Universities (lzujbky-2023-stlt01, lzujbky-2024-oy02, lzujbky-2025-eyt01)

When tunneling occurs out of generic initial states, a significant fraction of probability is lost at early times, during which the dynamics is governed by excited resonance states. However, first-principles analyses based on path-integrals have only captured the leading asymptotic behavior, during which the tunneling rate is dominated by the false vacuum contribution. In this work, we discuss the behavior in the preasymptotic regime from a first-principles path-integral perspective. We demonstrate how the relevant expressions can be evaluated systematically through semiclassical methods in the recently developed steadyon picture. This approach allows one to trace the role of the relevant physical scales, making transparent the underlying assumptions and approximations, and offering a clear path to establishing a systematically improvable framework to evaluate tunneling rates nonperturbatively.

United States

Joshua Lin

Bruno Scheihing-Hitschfeld

Spain

Thomas Steingasser

Path-integral predictions for preasymptotic quantum tunneling

We present an uncertainty-aware description of leading-power fragmentation for all-charm pentaquark states (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-wave <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>c</mi><mi>c</mi><mi>c</mi><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">⟩</mo></math>) at hadron colliders. We construct a multimodal set of collinear fragmentation functions, PQ5Q1.1, incorporating both perturbative and nonperturbative uncertainties. Perturbative effects are estimated via missing higher-order variations, while the nonperturbative wave function is modeled through controlled modifications of its transverse-momentum structure, consistently combined within a replicalike framework. The initial-scale input for constituent charm fragmentation is refined to describe both compact multiquark and diquark-driven production mechanisms. We employ the (sym) jethad interface to study <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>NLL</mi><mo>/</mo><msup><mrow><mi>NLO</mi></mrow><mo>+</mo></msup></math> (next-to-leading logarithmic/next-to-leading order) semi-inclusive pentaquark-plus-jet production at the HL-LHC and future Future Circular Collider. The bottom sector is left to future dedicated studies due to its enhanced sensitivity to nonperturbative modeling. Our results provide a flexible framework for uncertainty-controlled predictions, bridging exotic-hadron structure, heavy-flavor fragmentation, and high-energy QCD.

Francesco Giovanni Celiberto

Multimodal fragmentation of all-heavy pentaquarks: Uncertainty-aware predictions for hadron colliders

We show that rank-ordered jet rapidity distributions provide simple probes of high-energy QCD dynamics at the LHC. Comparing the Balitsky-Fadin-Kuraev-Lipatov-based Monte Carlo (bfklex) to standard event generators based on collinear factorization and Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) parton showers (pythia8, herwig7) in inclusive dijet topologies at 13 TeV, we find clear shape differences. While inclusive distributions can be very similar, rank-ordered spectra reveal that bfklex populates the rapidity interval more democratically, whereas DGLAP showers exhibit stronger edge enhancement and central concentration. We quantify the separation using the total-variation and one-dimensional Wasserstein distances between normalized histograms. The separation persists when applying the harder selection <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>p</mi><mrow><mi>T</mi><mo>,</mo><mi>j</mi></mrow></msub><mo>&gt;</mo><mn>60</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>H</mi><mrow><mi>T</mi><mn>2</mn></mrow></msub><mo>&gt;</mo><mn>250</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. Rank-ordered rapidity distributions thus compress exclusive multijet information into simple histograms, offering a new handle on high-energy radiation patterns measurable with existing data.

G. Chachamis

A. Sabio Vera

Portugal

D. Vaccaro

Order statistics for multijet events

We present high-precision predictions for associated <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi><mi>W</mi></math> production at the LHC that incorporate the next-to-next-to-leading-order hard and soft functions as well as the complete next-to-next-to-next-to-leading-order scale-dependent terms derived from the corresponding anomalous dimensions. These higher-order corrections, which dominate the full perturbative results, increase the next-to-leading-order cross section by more than 10%. Based on the comparison with ATLAS and CMS measurements, we directly extract the Cabibbo-Kobayashi-Maskawa matrix element <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">|</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>t</mi><mi>b</mi></mrow></msub><mo stretchy="false">|</mo><mo>=</mo><mn>0.99</mn><mo>±</mo><mn>0.03</mn><mo stretchy="false">(</mo><mrow><mi>expt</mi></mrow><mo stretchy="false">)</mo><mo>±</mo><mn>0.03</mn><mo stretchy="false">(</mo><mtext>theor</mtext><mo stretchy="false">)</mo></mrow></math> without assuming unitarity, achieving a precision comparable with the current world average value.

Jia-Le Ding

Hai Tao Li

Jian Wang

Approximate <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi mathvariant="normal">N</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>LO</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">N</mi><mn>3</mn></msup><mi>LO</mi></math> QCD predictions for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi><mi>W</mi></math> production

Measurements of Higgs boson Yukawa couplings to Standard Model (SM) fermions constrain radiative mass models for those species. Such models, motivated by the observed fermion mass hierarchy, act as foils for the SM tree-level mechanism: we cannot claim to have verified the standard mechanism if other possibilities also fit the data well. We construct a benchmark model which generates the top mass at tree level and the bottom, charm, tau, and tau Dirac neutrino masses at one-loop level. Current theoretical and experimental constraints on the model, including from Higgs decays, demonstrate it possesses viable regions of parameter space. We show that future improvements to measurements will not be able to rule out the model, only increase the scale of new physics required, illustrating how difficult it will be to verify the SM fermion mass generation mechanism with great precision. As a bonus, a dark matter candidate is shown to be capable of reproducing the correct relic density within the permitted parameter space.

Australia

Lucia Stockdale

Raymond R. Volkas

Higgs-Yukawa coupling constraints on a benchmark one-loop radiative mass model for the bottom, charm and tau

Using unitarity and causality, we derive an infinite tower of two-sided positivity bounds on the effective field theory coefficients which describe the propagation of heavy fields on de Sitter spacetime. We design this effective field theory (EFT) to describe propagators with the in-in boundary conditions that are relevant for cosmological correlators. Our positivity bounds therefore identify EFT correlators that can never emerge from a consistent underlying model of inflation. This implies nontrivial constraints on primordial non-Gaussianity; for instance the cosmological collider oscillations in the squeezed bispectrum from the exchange of a heavy scalar are tied to the shape of its EFT background.

Taiwan

Mang Hei Gordon Lee

United Kingdom

Scott Melville

Propagator positivity bounds for cosmological correlators

We present a machine-learning-based anomaly detection strategy designed to identify anomalous physics in events containing resonant Standard Model physics and demonstrate this method on the final state of a Higgs boson decaying to two photons. The demonstration targets high-dimensional deviations in the region of phase space containing the Higgs mass peak in a fully signal-agnostic manner. A latent-space embedding, learned from event kinematics, enables the use of a large set of potentially sensitive features. Backgrounds are estimated using a hybrid approach that combines machine-learning-based generative modeling with traditional simulation, and a discriminator is trained in the latent space to distinguish data from background estimates. After applying a selection on the classifier output, the invariant mass distribution of the diphoton system is examined for localized excesses above the simulated Higgs peak. We benchmark the sensitivity of this strategy using simplified simulated proton-proton collisions corresponding to data recorded during Run 2 of the LHC and show that the method can provide significant improvements in sensitivity, even for small signal injections that could remain undetected in an inclusive analysis. These results demonstrate that the proposed strategy is a promising and viable approach for future searches and should be applied to recorded collider data.

Chi Lung Cheng

Sarah Demers

Sascha Diefenbacher

Runze Li

Benjamin Nachman

Dennis Noll

Weakly supervised anomaly detection in events with a Higgs boson and exotic physics

We propose a nonperturbative completion of two-point correlators in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed conformal field theories (CFTs) and analyze their behavior at distance scales shorter than the fundamental length scale set by the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math> deformation. Building on the interpretation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math> deformation as a coupling to two-dimensional quantum gravity with a unique built-in length scale, we advance the study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed CFTs as a toy model for Planckian physics. As we probe shorter distances, trans-Planckian oscillations are followed by a super-Planckian regime in which correlations are typically suppressed by geometric randomness, in contrast to the power-law growth characteristic of CFTs. Moreover, their dependence on distance becomes exponentially weaker, suggesting that the underlying geometric structure has been largely erased—a behavior broadly consistent with expectations for quantum spacetime in this regime.

Japan

Shinji Hirano

Vinayak Raj

Nonperturbative effects in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed conformal field theories: A toy model for Planckian physics