Finding a complete and yet minimal on-shell basis of operators of a given mass-dimension that are compatible with a specific set of transformation properties is the first step in any Effective Field Theory description. This step is the main bottleneck for systematic studies of leading logarithmic corrections to integer-power lattice artifacts in Symanzik Effective Field Theory targeting various local fields and lattice actions. The focus on discrete symmetry transformations in lattice field theory, especially reduced hypercubic spacetime symmetry with Euclidean signature, complicates the use of standard continuum field theory tools. Here, a new Python package is being presented that targets the typical lattice field-theorist’s use cases. While the main target lies on continuum EFTs describing 4D non-Abelian lattice gauge theories, the applicability can be extended beyond Effective Field Theories. New discrete symmetries, twisted masses, or the introduction of boosts are just a few examples of possible extensions that can be easily implemented by the user. This should allow for a wider range of theories and applications beyond the initial focus of this package. The general functionality of the package is explained along the lines of three examples: The $$\mathop {\textrm{O}}(a)$$ operator basis of the axial-vector in Wilson QCD, operator bases compatible with the symmetries of unrooted Staggered quarks as well as a pedestrian derivation of a $$B^*(\textbf{p})\pi (-\textbf{p})$$ operator with pseudo-scalar quantum numbers. Each example makes use of an increasing range of features and requires user-defined extensions show-casing the versatility of the package.

Spain

Switzerland

Nikolai Husung

opbasis: a Python package to derive minimal operator bases

We argue that the polynomial degeneracies of curvature invariants can act as geometric selection rules for spacetime singularities in modified theories of gravity. The degeneracies arise purely from the algebraic structure of Riemannian geometry and impose non-trivial constraints on the effective energy–momentum tensor. We derive these constraints for metric $\textit{f}$($\textit{R}$) gravity and a wide class of scalar–tensor theories to show that a singularity formation is generally occluded by curvature and/or scalar-induced anisotropies. Therefore, formation of a singularity in modified theories of gravity is not always a generic outcome but can occur only along algebraically admissible branches selected by Riemannian curvature invariants.

India

Soumya Chakrabarti

Geometric selection rules for singularity formation in modified gravity

This study reports on the design, simulation, construction, and testing of a full-size prototype of the multi-wire drift chamber for the CSR external-target experiment. The multi-wire drift chamber array incorporates drift cells of three different sizes: 8 $$\times $$ 8 mm $$^{\textrm{2}}$$ , 10 $$\times $$ 10 mm $$^{\textrm{2}}$$ , and 15 $$\times $$ 15 mm $$^{\textrm{2}}$$ . Simulation studies were carried out to compare their electron drift time spectra, R-T relations, and position resolution. The prototype was constructed based on the design of the multi-wire drift chamber closest to the target. Since the beam passes through the center region of the multi-wire drift chamber, the prototype features a special beam avoidance design. The design ensures that the detector is sensitive to reaction products while remaining unresponsive to heavy ion beams. The size of the prototype is 930 $$\times $$ 1660 mm $$^{\textrm{2}}$$ , comprising 960 drift cells. Testing was conducted with dedicated electronics. An energy resolution of 22% was achieved for the $$^{\textrm{55}}$$ Fe source; the track residuals were approximately 300 $$\upmu $$ m for the cosmic rays; the detection efficiency of each layer exceeds 96% for the cosmic rays.

China

Zhoubo He

Zhi Qin

Xiangjie Wen

Herun Yang

Xianglun Wei

Peng Ma

Rongjiang Hu

Zhijie Li

Tao Chen

Yuansheng Yang

Shichao Ren

Zhixuan He

Chengui Lu

Xiuling Zhang

Tingting Hou

Zihe Su

Canwen Liu

Shihai Wen

Haoran Yang

Junwei Yan

Zhe Cao

Zhi Deng

Jie Kong

Yuhong Yu

Zhigang Xiao

Limin Duan

A full-size multi-wire drift chamber prototype for the CSR external-target experiment

This work explores exotic signatures from confining dark sectors that may arise in the $$e^+e^-$$ collision mode at the Future Circular Collider. Assuming the Higgs boson mediates the interaction between the Standard Model and the dark sector, dark quarks can be produced in $$e^+e^-$$ collisions. The ensuing strong dynamics may lead to semi-visible jet final states, containing both visible and invisible particles. We investigate semi-visible jets with different fractions of invisible states, and enriched in leptons and photons. When the invisible component is large, selections based on kinematic features, such as the missing energy in the event, already provide good signal-to-background discrimination. For smaller invisible fractions, the reduced missing energy makes these signals more similar to Standard Model events, and we therefore employ a graph neural network jet tagger exploiting differences in jet substructure. This machine learning strategy improves sensitivity and enhances the discovery prospects of Higgs boson-induced semi-visible jets at the Future Circular Collider. Our results show that the proposed strategy can effectively probe a wide parameter space for the models considered, and a variety of signatures, constraining the Higgs boson exotic branching ratios into dark quarks at the permille-level.

Cesare Cazzaniga

Annapaola Cosa

Germany

Felix Kahlhoefer

Andrea Maria

Roberto Seidita

Emre Sitti

Probing the Higgs portal to a strongly-interacting dark sector at the FCC-ee

We propose a novel model in which the Universe is created as a pair of coordinate-reversed counterparts, forming a globally CPT-symmetric system that permits local CPT violations within each sector. This framework naturally introduces a mirror universe with opposite chiralities and reversed microscopic time coordinates, providing a geometric interpretation of time reversal without relying on initial–final state interchange. We investigate the consequences of local CPT violation in each universe, which induces a mass difference between the real inflaton and anti-inflaton fields. Such an asymmetry can modify reheating temperatures and naturally generate the observed matter–antimatter asymmetry in both universes.

Finland

M. Chaichian

Georgia

M. Gogberashvili

Russia

M. Mnatsakanova

T. Tsiskaridze

$\textit{CPT}$ violation, mirror world and implications for baryon asymmetry

We consider application of the analytic functional approach to the conformal field theories associated with mean field theory and Wilson–Fisher fixed point. We study the constraints imposed by the crossing symmetry on the coefficients of the operator product expansion. Making use of these constraints along with a few other additional inputs, we obtain expressions of the coefficients of the operator product expansion up to first order of $$\epsilon $$ .

Bhaskar Khanikar

Subir Mukhopadhyay

Application of analytic functionals to mean field theory and Wilson–Fisher fixed point

We explore a cosmological framework in which a Gauss–Bonnet (GB) coupled scalar field, acting as dark energy, interacts with a fermionic dark matter field through a coupling obtained from the point of view of particle physics. This setup is inspired by string/M-theory, and two representative scalar field potentials are investigated: exponential and power-law. A distinctive feature of the GB-coupled models is their potential to alter the propagation speed of gravitational waves (GWs), a property with significant implications in light of recent multi-messenger astrophysical observations. To account for this, we analyze models under two scenarios: one where the GW speed differs from that of light and the other where they are equal, but all consistent with current observational constraints. The dynamical evolution of the system is investigated by reformulating the field equations into an autonomous dynamical system, enabling a detailed analysis of the Universe’s long-term behavior, including the radiation-, matter- and dark energy-dominated epochs. We constrain the model parameters using a broad set of recent observational data, including mock high-redshift measurements from the Roman Space Telescope. Our findings indicate that both potentials yield cosmologies that are in excellent agreement with current data, closely tracking the expansion history predicted by the standard $$\Lambda $$ CDM model, while still allowing room for subtle deviations that could be tested by future observations.

Japan

Simran Arora

Saddam Hussain

United States

Benjamin Rose

Anzhong Wang

Interacting bosonic dark energy and fermionic dark matter in Einstein scalar Gauss–Bonnet gravity

The modification of jets by interaction with the quark gluon plasma has been extensively established through the comparison of observables computed for samples of jets produced in nucleus-nucleus collisions and proton-proton collisions. The presence of vacuum-like jets, jets that experienced little interaction with the quark gluon plasma, in the nucleus-nucleus samples dilutes the overall observed modification hindering the detailed study of the underlying physical mechanisms. The ability to ascertain on a jet-by-jet basis the degree of modification of a jet would be an invaluable step in overcoming this limitation. We consider a Transformer classifier, trained on a low-level representation of jets given by the 4-momenta of all its constituents. We show that the Transformer is able to capture discriminating information not accessible to other architectures which use high-level physical observables as input. The Transformer allows us to identify, in the experimentally relevant case where both medium response and underlying event contamination are accounted for, a class of jets that have been unequivocally modified. Further, we perform a robust estimate of the upper bound for the fraction of jets in nucleus-nucleus collisions that are, for all purposes, indistinguishable from those produced in proton-proton collisions.

Portugal

United Kingdom

Miguel Crispim Romão

João Gonçalves

José Milhano

Quantifying vacuum-like jets in heavy-ion collisions: a machine learning study

We construct bi- and uni-vector deformations of 10d heterotic supergravity solutions with the gauged double field theory approach. We construct a generalization of the “open/closed” map for this case and consider some examples of the deformed solutions, particularly for the F1 string solution.

Kirill Gubarev

Konstantin Sovit

Poly-vector deformations of heterotic supergravity solutions

Christian Biello

Leonardo Bonino

Erratum: Time-like heavy-flavour thresholds for fragmentation functions: the light-quark matching condition at NNLO