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.

China

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)

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

Semileptonic $$b\rightarrow c\tau \bar{\nu }_{\tau }$$ decays are powerful probes of non-Standard-Model effects within an effective-field-theory (EFT) framework, but fully exploiting them in current and future data demands combinations that maximise sensitivity while controlling biases from Standard-Model-based modelling and from theory inputs that are shared, and therefore correlated, across analyses in different experiments. We present a first sensitivity study of a $\textit{combined}$ extraction of Wilson coefficients in $$\bar{B}\rightarrow D^{(*)}\tau \bar{\nu }_{\tau }$$ decays using LHCb- and Belle II-like analysis configurations. Detector simulations for signal and backgrounds are typically generated under Standard Model assumptions; if non-SM contributions are present, this can bias the fitted Wilson coefficients. In addition, hadronic inputs such as form-factor parameters of signal and background components are common across analyses, requiring a consistent treatment of fully correlated effects in combinations. To avoid repeating large-scale detector simulation for each EFT hypothesis, we use event-by-event reweighting to map simulated samples to arbitrary combinations of Wilson coefficients. We then compare a simultaneous fit across multiple $$\bar{B}\rightarrow D^{(*)}\tau \bar{\nu }_{\tau }$$ channels and datasets with a combination based on post-fit averages. Sharing Wilson coefficients and common form-factor parameters in the simultaneous fit reduces model-induced biases and improves sensitivity relative to independent fits, providing a robust and scalable strategy for precision EFT constraints in $$b\rightarrow c\tau \bar{\nu }_{\tau }$$ transitions using forthcoming LHCb and Belle II datasets.

Germany

Johannes Albrecht

Florian Bernlochner

Marco Colonna

Lorenz Gärtner

Abhijit Mathad

Biljana Mitreska

Markus Prim

Ilias Tsaklidis

Joint LHCb–Belle II prospects to constrain new physics in $$B\rightarrow D^{(*)}\tau \nu $$

J.G. Wang

Z.C. Li

Z.Y. Zhang

Z.G. Gan

Japan

A.N. Andreyev

M.H. Huang

L. Ma

M.M. Zhang

H.B. Yang

C.L. Yang

Y.H. Qiang

Z.H. Li

X.Y. Huang

G. Xie

L. Zhu

H. Zhou

X. Zhang

J.H. Zheng

S.Y. Xu

Z. Zhao

L.C. Sun

F. Guan

X.L. Wu

W.X. Huang

Y.L. Tian

Y.S. Wang

J.Y. Wang

Z.W. Lu

Y. He

L.T. Sun

Z.Z. Ren

S.G. Zhou

Russia

V.K. Utyonkov

A.A. Voinov

Yu. S. Tsyganov

A.N. Polyakov

Corrigendum to “Decay properties of new isotopes 235Bk and 231Am” [Physics Letters B 875 (2026) 140365]

We present a comprehensive study of the Muonic Portal to Vector Dark Matter (MPVDM), a minimal extension of the Standard Model featuring a new $\textit{SU}$ (2) gauge symmetry and vector-like muons that mediate interactions between the dark sector and the muon sector. We show that the MPVDM can simultaneously reproduce the observed dark matter relic abundance and accommodate scenarios consistent with the current experimental determination of the muon anomalous magnetic moment, ($\textit{g}$ − 2) , as well as scenarios allowing for a non-zero new physics contribution to ($\textit{g}$ − 2) . One of the key results of this work is the identification of a $\textit{generic off-resonance velocity-suppression mechanism}$ that allows light (≲ 1 GeV) vector dark matter to evade stringent CMB constraints near 2$\textit{m}$ ≃ $$ {m}_{H_D} $$ . A five-dimensional parameter scan combining cosmological, collider, and precision constraints shows that scenarios admitting a non-zero contribution to ($\textit{g}$ − 2) favour sub-GeV dark matter realised near the scalar resonance with a dark gauge coupling $\textit{g}$ ∼ 10 and TeV-scale vector-like muons, while scenarios consistent with a Standard-Model-like ($\textit{g}$ – 2) allow a broad viable dark matter mass range from sub-GeV to multi-TeV. By recasting ATLAS and CMS searches for $\textit{μ}$ final states with missing transverse energy, we derive a lower bound of approximately 850 GeV on the vector-like muon masses. We further identify distinctive multi-lepton collider signatures, including six-, eight-, and ten-muon final states as well as mixed muon-electron topologies with displaced electron pairs, providing striking and well-motivated targets for searches at the LHC and future colliders.

Alexander Belyaev

Italy

Luca Panizzi

Thailand

Nakorn Thongyoi

Sweden

Franz Wilhelm

The Muonic Portal to Vector Dark Matter: connecting precision muon physics, cosmology, and colliders

The determination of the neutrino mass ordering is one of the flagship goals in particle physics. A well-known and powerful synergy emerges when combining high-precision measurements of the effective atmospheric mass-squared splitting from electron antineutrino disappearance in reactor experiments with that from muon (anti)neutrino disappearance in accelerator-based long-baseline experiments. To fully exploit this synergy, percent-level precision in the atmospheric mass splitting is required—a target that JUNO is expected to achieve within a few months of data taking. This motivated the formulation of a mass ordering sum rule for neutrino disappearance channels, which shows that by combining data from T2K and NOvA with JUNO after one year of operation, the neutrino mass ordering can be determined at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mi>σ</mi></math> confidence level. Since JUNO has recently started taking data, it is timely to ask whether this sum rule remains robust in the presence of new physics. We identify the necessary conditions for new physics to affect the sum rule and demonstrate that, in some cases, such effects could lead to an incorrect inference of the mass ordering. As concrete examples, we consider scalar nonstandard interactions (SNSI) and neutrinos coupled to an ultralight scalar field. We find that, for SNSI, current constraints render any modification of the sum rule negligible, whereas in the latter case, the inference of the ordering requires caution. Nevertheless, these effects can be disentangled, illustrating how the sum rule can also be used to search for new physics.

United States

Brazil

Gustavo F.S. Alves

Hiroshi Nunokawa

Renata Zukanovich Funchal

Impact of new physics on the JUNO-long-baseline synergy in the neutrino mass ordering determination

The orbital evolution of compact binary systems depends on the component masses and spins as well as the underlying theory of gravity. Because the orbital dynamics directly determine the frequency evolution of gravitational-wave signals, tracking this evolution provides a sensitive probe of general relativity (GR). We introduce a method that coherently stacks time-frequency pixel energies along the observed orbital-frequency trajectory while allowing controlled shifts along the frequency axis. The resulting stacked energy reveals a clear signature of the dominant quadrupole mode in GR. When an alternative theory of gravity is injected and analyzed with GR waveforms, the corresponding energy distribution in the time-frequency plane is markedly different. We use this behavior to formulate a new consistency test based on a normalized deviation between the observed signal and the posterior predictions from theoretical waveforms. Using waveforms in beyond-GR scenarios within the sensitivity of second-generation interferometers, we demonstrate the ability of this method to identify departures from GR. We also examine missing physics within GR itself by analyzing an eccentric binary and recovery with a quasi-circular model. Finally, we apply the method to GW190814 and find signatures consistent with higher-order multipoles.

Debtroy Das

Belgium

Soumen Roy

India

Anand Sengupta

Uzbekistan

Cosimo Bambi

Probing missing physics from inspiralling compact binaries via time-frequency tracks