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.

China

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

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.

United States

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

Hao-Fu Zhu

Guo-Zhu Liu

Xufen Wu

Corrigendum to “Rapid cooling of the Cassiopeia A neutron star due to superfluid quantum criticality” [Physics Letters B 879 (2026) 140591]

We analyze how NA64$\textit{μ}$ can contribute to the global SMEFT program demonstrating that it can probe two effective four-lepton operators completely unbounded so far and break one of the current flat directions. Furthermore, we also study an extension of SMEFT that includes fermion singlets of the SM gauge group in the low energy field content. This effective field theory, usually dubbed $\textit{ν}$SMEFT, is well motivated by the observation of light neutrino masses and leptonic mixing. We find that NA64$\textit{μ}$ can constrain three unbounded four-fermion operators of the $\textit{ν}$SMEFT. We derive the current bounds on these operators and compute the future sensitivity.

Switzerland

Paolo Crivelli

Spain

Josu Hernández-García

Jacobo López-Pavón

Víctor Martín Lozano

Laura Molina Bueno

First bounds on effective muon interactions using the NA64$\textit{μ}$ experiment at CERN

We present a systematic analysis of the Higgs signal strengths at 125 GeV and 95 GeV in a non-supersymmetric $ U(1)_X $ model with vector-like fermions ( $ U(1)_X $ VLFM). This framework extends the Standard Model (SM) by introducing an additional $ U(1)_X $ gauge symmetry, three right-handed neutrinos, two singlet Higgs fields ($\textit{ϕ}$ and $\textit{S}$), and one generation of vector-like quarks and leptons. The scalar fields mix in the neutral CP-even sector, yielding two Higgs-like states around 95 GeV and 125 GeV. We perform a $ \chi^2 $ analysis that combines the Higgs signal strength measurements at 125 GeV from ATLAS and CMS, including the $ \gamma\gamma $ , $ WW^* $ , $ ZZ^* $ , $ b\bar{b} $ , and $ \tau\bar{\tau} $ channels, together with the 95 GeV excesses observed in the diphoton and $ b\bar{b} $ final states reported by CMS and LEP. Our results indicate that the $ U(1)_X $ VLFM successfully reproduces the observed signal strengths of the 125 GeV Higgs while simultaneously explaining the 95 GeV excess. The parameters $ g_X $ , $ g_{YX} $ , $ v_S $ , $ v_P $ , and the new Yukawa couplings play a crucial role in achieving this consistency.

Rong-Zhi Sun

Shu-Min Zhao

Meng-Zi Cao

Song Gao

Portugal

Xing-Xing Dong

Higgs Bosons at 95 and 125 GeV in the $\textit{U}$(1) $\textit{X}$ VLFM * Supported by National Natural Science Foundation of China (NNSFC) (2075074), Natural Science Foundation of Hebei Province (A2023201040, A2022201022, A2022201017, A2023201041), Natural Science Foundation of Hebei Education Department (QN2022173), the Project of the China Scholarship Council (CSC) (202408130113). This work is also supported by Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the project UID/00777/2025 (https://doi.org/ 10.54499/UID/00777/2025)

The internal structure of the light scalar state $ a_0(1450) $ has not been definitively determined; it may comprise multiple possible configurations. Among these, it may be regarded as a $ q\bar{q} $ state. Based on this possibility, we use QCD light-cone sum rules to study the semileptonic decay process $ D \to a_0(1450)\ell \nu_\ell $ with $ \ell=(e, \mu) $ and to test this hypothesis. First, we construct two twist-2 light-cone distribution-amplitude schemes based on the light-cone harmonic-oscillator model, and present their moments $ \langle\xi^{n}\rangle |_{\mu} $ and Gegenbauer moments $ a_{n}(\mu) $ at $ \mu_0=1\; {\rm{GeV}} $ and $ \mu_k= 1.4\; {\rm{GeV}} $ for $ n=(1,3,5) $ . In the large-recoil region, we obtain the transition form factors (TFFs): $ f_+^{({\rm{S}}1)}(0) = $ $ 0.836_{-0.119}^{+0.116} $ , $ f_+^{({\rm{S}}2)}(0)=0.767_{-0.105}^{+0.106} $ , and $ f_-(0)=0.630_{-0.077}^{+0.078} $ . A simplified series expansion $ z(q^2, t) $ is used to extrapolate the TFFs to the entire physical $ q^2 $ region. For $ q^2=10^{-5} \; {\rm{GeV}}^2 $ , we compute the angular distribution of the differential decay width ${{\rm d}\Gamma}/{{\rm d}\cos\theta_\ell }$ over the range $ \cos\theta_\ell \in [-1,1] $ . Subsequently, we obtain the differential decay widths and branching fractions for $ D^0 \to a_0(1450)^- \ell^+ \nu_\ell $ and $ D^- \to a_0(1450)^0 \ell^- \bar{\nu}_\ell $ , with branching fractions of order $ 10^{-6} $ . Finally, we analyze three angular observables for the semileptonic decay process $ D^- \to a_0(1450)^0 \ell^- \bar{\nu}_\ell $ : the forward–backward asymmetry $ {\cal{A}}_{\rm{FB}} $ , the lepton polarization asymmetry $ {\cal{A}}_{\lambda_\ell} $ , and the $ q^2 $ -differential flat term $ {\cal{F}}_{\rm{H}} $ .

Ya-Lin Song

Yin-Long Yang

Ye Cao

Xue Zheng

Hai-Bing Fu

Searching the possibility of $\textit{a}$ $_{0}$(1450) scalar state being a q q state structure via charmed meson semileptonic decays * Supported in part by the National Natural Science Foundation of China (12265010), and the Guizhou Provincial Department of Science and Technology (MS[2025]219, CXTD[2025]030)

Density functional theory is a practical approach for solving quantum many-body problems with available computational resources. The complexity of the nuclear force makes constructing an accurate nuclear energy density functional much more challenging. The feasibility of constructing a nuclear covariant energy density functional with deep neural networks is demonstrated. This physics-guaranteed neural network approach achieves high accuracy in predicting nuclear energy density and exhibits significantly better extrapolation abilities than traditional machine learning methods for binding energies. When combined with the existing covariant density functional, the neural network approach improves the binding energy accuracy from 644 keV to 86 keV in the known region and also effectively captures the microscopic shell effect. Furthermore, its extrapolation performance is also significantly enhanced, achieving an accuracy of approximately 5 MeV even when extrapolating up to 30 steps. This work paves the way for the construction of accurate nuclear energy density functionals through machine learning.

W.F. Li(李伟峰)

Z.M. Niu(牛中明)

H.Z. Liang(梁豪兆)

Y.F. Niu(牛一斐)

B.H. Sun(孙保华)

Construction of nuclear covariant energy density functional from a physics-guaranteed neural network approach

Recent studies have shown that quantitative concepts from quantum information theory can play a role in analyzing collider physics, including elucidating new physics. In this paper, we study various quantum information measures including magic, trace distance, and fidelity distance, in generic new physics scenarios modeled by the standard model effective field theory. We argue that such measures can indeed show up differences with respect to the pure standard model, and we compare our results with similar findings for the concurrence discussed previously in the literature. We examine the relative sensitivity of different measures to new physics in two-dimensional bins of the top pair invariant mass and scattering angle, finding that the concurrence, magic, and trace distance each emerge as the best measure in at least some regions of the phase space. This highlights the importance of exploring multiple quantum information measures in the hunt for beyond the standard model physics.

United Kingdom

Rafael Aoude

Hannah Banks

Chris D. White

Australia

Martin J. White

Probing new physics in the top sector using quantum information

Mimetic gravity has emerged as a compelling extension of General Relativity (GR), originally motivated by the attempt to isolate the conformal degree of freedom of the gravitational field. By reparametrizing the physical metric in terms of an auxiliary metric and a scalar field, the theory naturally gives rise to a longitudinal degree of freedom that mimics the behavior of cold dark matter. This review provides a comprehensive survey of the theoretical landscape of mimetic gravity and its multifaceted applications to cosmology and high-energy physics. We begin by examining the original formulation and addressing the fundamental question of its equivalence to GR, highlighting how a singular disformal transformation introduces new physical degrees of freedom. We then explore minimal generalizations that lead to unified cosmological models, including mimetic matter scenarios and extensions into $$f(R, \phi )$$ gravity, which allow for the reconstruction of any desired expansion history. Significant attention is given to the “limiting curvature” hypothesis through $$f(\Box \phi )$$ modifications, providing a classical mechanism for resolving cosmological and black hole singularities. We critically assess the challenges facing the theory, specifically the gradient and ghost instabilities identified in cosmological perturbations, and discuss modern resolutions such as ghost-free mimetic massive gravity and covariant formulations of Hořava gravity. Finally, we discuss the role of the mimetic field in the early universe, specifically in the context of asymptotically free gravity and the resolution of the self-reproduction problem in inflation.

Lebanon

Ola Malaeb

The theoretical landscape of mimetic gravity: a comprehensive review

Rare kaon decays provide sensitive tests of new physics. In this work, we focus on scalar and pseudoscalar operators, analysing the <math altimg='si24.svg'><mrow><mi>K</mi><mo>&#8594;</mo><mi>&#960;</mi><msup><mi>&#8467;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>&#8722;</mo></msup></mrow></math> and <math altimg='si25.svg'><mrow><mi>K</mi><mo>&#8594;</mo><msup><mi>&#8467;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>&#8722;</mo></msup></mrow></math> decays. We highlight the complementary role of different modes: <math altimg='si26.svg'><mrow><msup><mi>K</mi><mo>+</mo></msup><mo>&#8594;</mo><msup><mi>&#960;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>&#8722;</mo></msup></mrow></math>, in particular the forward&#8211;backward asymmetry in the muon channel as a clean probe of scalar effects, the stringent constraints from <math altimg='si1.svg'><mrow><msub><mi>K</mi><mi>L</mi></msub><mo>&#8594;</mo><msup><mi>&#956;</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>&#8722;</mo></msup></mrow></math>, and the discovery potential of future measurements of <math altimg='si5.svg'><mrow><msub><mi>K</mi><mi>S</mi></msub><mo>&#8594;</mo><msup><mi>&#956;</mi><mo>+</mo></msup><msup><mi>&#956;</mi><mo>&#8722;</mo></msup></mrow></math> and <math altimg='si7.svg'><mrow><msub><mi>K</mi><mi>L</mi></msub><mo>&#8594;</mo><msup><mi>&#960;</mi><mn>0</mn></msup><msup><mi>&#8467;</mi><mo>+</mo></msup><msup><mi>&#8467;</mi><mo>&#8722;</mo></msup></mrow></math>. The interplay between charged and neutral modes underscores the complementarity of NA62, the LHCb upgrade, and KOTO-II.