<p>Here we investigate a general class of massless local theories of spin 2 and spin 3, both invariant under generalized transverse diffeomorphisms (TDiff). We identify the ghost-free region in their parameter space and show the relationship of those models with the “doublet” action stemming from the tensionless limit of the open bosonic string field theory (for symmetric tensors). The connection is implemented via a nonlocal field redefinition which introduces a Stueckelberg-like field of rank 0 (rank 1) for the spin-2 (spin-3) case. An apparent mismatch between most TDiff models and the “doublet” action has led us to prove a nontrivial equivalence among TDiff models, thereby restoring consistency. Any point in the parameter subspace of ghost-free TDiff models is equivalent to any other one within that subspace. In particular, they are all physically equivalent to their simplest versions known as Maxwell-like models. So, the physical TDiff models seem to differ from each other by a Becchi-Rouet-Stora-Tyutin cohomologically trivial term.</p>

Brazil

R. Schimidt Bittencourt

D. Dalmazi

B. dos S. Martins

E.L. Mendonça

Equivalence of spin-2 and spin-3 models invariant under transverse diffeomorphisms and the tensionless limit of string theory

The Hubble tension has profoundly shaped modern cosmological research. This study explores its impact on the early-universe physics in the modified emergent dark energy (MEDE) and $$\Lambda $$ CDM model using Planck PR4, BK18, DESI2024/2025, and supernova samples (Pan+, Union3). First, Hubble constant negligibly affects the tensor-to-scalar ratio ( $$r < 0.031$$ at 95%C.L.). Inclusion of DESI2025 achieves a 46% uncertainty reduction in key parameters. For CMB power spectra, DESI systematically amplifies TT/BB spectral discrepancies. Second, electron ionization fractions $$X_e(z)$$ display pronounced deviations from the $$\Lambda $$ CDM model at $$z=9.17$$ , suggesting a connection between Hubble tension and reionization history. This finding resonates with JWST measurements on high-redshift galaxy evolution. Future observations, such as 21-cm surveys, are highly anticipated to resolve these tensions by probing early-universe evolution and dark energy interactions.

China

Ming-Jian Zhang

Maoyou Yang

Junmei Wang

Testing influence of Hubble tension on the early Universe

The manifest disparity in Hawking radiation temperatures between black hole and cosmological horizons in de Sitter (dS) spacetime reveals a non-equilibrium thermal configuration, inherently violating thermodynamic stability criteria. This asymmetry poses significant challenges to the systematic analysis of dS thermodynamics. In this study, we construct a thermodynamic framework for dS spacetime under the condition that the system’s thermodynamic quantities adhere to the first law of thermodynamics, while enforcing thermal equilibrium between horizons through radiation temperature-equivalent conditions. Our ansatz postulates that spacetime entropy constitutes both horizon entropy contributions with a supplementary correction term. Through variational analysis constrained by equilibrium thermodynamics, we derive and solve thermodynamic constraints to obtain corrected entropy relations that explicitly resolve the two-horizon entropy puzzle for $\textit{n}$-dimensional charged dilaton-dS black holes. Utilizing these corrected entropy relations, we renormalize associated thermodynamic quantities, thereby establishing self-consistent extended thermodynamics. Numerical solutions of the Gibbs criteria reveal parameter-dependent critical points, where heat capacity is diverging signal possible second-order phase transitions. The system manifests phase transition phenomena, structurally homologous to liquid–gas transition in conventional thermodynamic systems. We proved that the system satisfies the conditions for equilibrium stability, allowing equilibrium phase transitions to occur near critical points.

Hui-Hua Zhao

Yun-Zhi Du

Yu-Bo Ma

Entropy correction and phase transition of $\textit{n}$-dimensional charged dilaton dS black holes

Linear Standard Model (SM) extensions, defined as new particles that can couple linearly to SM fields, form a motivated and finite set of simplified models for exploring phenomenology Beyond the SM (BSM). Heavy BSM particles may be integrated out to obtain their low-energy effects in the SM Effective Field Theory (SMEFT) parametrised by the Wilson coefficients of higher-dimensional operators. We compute and map the dimension-6 SMEFT operator structure of all scalar and fermion linear SM extensions up to one-loop order, thus extending the existing tree-level dictionary of results. Explicit analytic matching expressions for the Wilson coefficients are provided as both Python and Mathematica code in a GitHub repository accessible through links embedded in our main table for each coefficient and within a Python package. We apply our map to highlight the sensitivity to heavy new physics of a $\textit{Z}$-pole run at a future Tera-$\textit{Z}$ factory; at one loop, with unit couplings, all linear SM extensions can be indirectly probed by electroweak precision measurements up to $$ \mathcal{O}(10) $$ TeV.

Spain

Australia

John Gargalionis

France

Jérémie Quevillon

Germany

Pham Vuong

United Kingdom

Tevong You

Linear Standard Model extensions in the SMEFT at one loop and Tera-$\textit{Z}$

We construct supersymmetric rotating AdS black holes in 5d $$ \mathcal{N} $$ = 2 gauged supergravity coupled to two vector multiplets and a universal hypermultiplet, and verify their microscopic counting from the superconformal index of the dual 4d class $$ \mathcal{S} $$ $$ \mathcal{N} $$ = 1 SCFTs. From the CFT, we perform the Legendre transform of the index to the microcanonical ensemble. The theories are parametrized by a rational number $\textit{z}$ which enters into the extremization equations making them more challenging to solve. We present a method to address these difficulties and highlight the subtleties involved. From the gravity perspective, we identify a charged, rotating black hole whose Bekenstein-Hawking entropy matches the prediction from the index for $\textit{z}$ = ±1. Beyond this value, where hypermultiplet scalars are nonzero, we construct the near-horizon extremal geometry perturbatively around $\textit{z}$ = 1 and verify that the entropy is consistent with the CFT prediction. We discuss the thermodynamics and verify the near-horizon versions of the first law of thermodynamics and the supersymmetric condition. In this setting, our analysis characterizes the first construction of a rotating black hole geometry in a 5d $$ \mathcal{N} $$ = 2 supergravity theory that contains hypermultiplets.

Belgium

Marina David

Annelien Vekemans

Microstates of AdS

We construct new families of supersymmetric AdS solutions in both massive and massless Type IIA supergravity via deformations to known backgrounds preserving $$ \mathcal{N} $$ = (4, 0) and $$ \mathcal{N} $$ = (6, 0) supersymmetry. These deformations are performed along internal isometries and lead to backgrounds with fully preserved or reduced supersymmetry. Using the formalism of $\textit{G}$-structures, we systematically characterise the resulting geometries and track the evolution of their supersymmetric properties under the deformation. In particular, we identify transitions among SU(3), SU(2), and identity structures, and demonstrate the preservation of Killing spinors through explicit spinor bilinear constructions. Additionally, we investigate D-brane embeddings in the deformed geometries, uncovering stable and supersymmetric configurations supported by the new backgrounds. Our results offer new insights into the classification of AdS flux vacua and provide a concrete framework for understanding their potential holographic duals.

Anayeli Ramírez

Czechia

Salomón Zacarías

On deformations of AdS

We present an analytic calculation of the integrated double-emission eikonal function of a massive and a massless emitter whose momenta are at an arbitrary angle to each other. This quantity provides one of the required ingredients for extending the nested soft-collinear subtraction scheme to processes with massive final-state particles. To calculate it, we use the standard methodology involving reverse unitarity and its extension to cases with Heaviside functions, integration-by-parts technology and reduction to master integrals, and differential equations. In addition, we also describe a semi-numerical method based on the subtraction of infra-red and collinear singularities from the eikonal function, allowing us to extract divergences of the integrated eikonal function analytically, and to derive a simple integral representation for the finite remainder.

Dennis Horstmann

Kirill Melnikov

Ming-Ming Long

Andrey Pikelner

Integral of the double-emission eikonal function for a massive and a massless emitter at an arbitrary angle

We describe the most general local, Lorentz-invariant, effective field theory of scalars, fermions and gauge bosons up to mass dimension 6. We first obtain both a Green and a physical basis for such an effective theory, together with the on-shell reduction of the former to the latter. We then proceed to compute the renormalization group equations for the bosonic operators of this general effective theory at one-loop order.

Renato Fonseca

Italy

Pablo Olgoso

José Santiago

Renormalization of general Effective Field Theories: formalism and renormalization of bosonic operators

I investigate the higher dimensional black holes of quartic quasitopological-scalar gravity within the scope of extended quasitopological electromagnetism. It is demonstrated that only positive values of the quartic quasitopological parameter can result in physically acceptable solutions. In accordance with the values of the mass, conformal coupling constants, and quasitopological electromagnetic charges, the derived solution characterizes the dyonic hairy black holes with a single horizon, two horizons, and naked singularity. I also demonstrate that this solution has an essential curvature singularity at the centre $$r=0.$$ Additionally, the thermodynamic and conserved quantities for the resultant solution are worked out and the extended first law satisfied by these quantities is established. Ultimately, I address the consequences of a scalar field and electromagnetic charges on the local thermodynamic stability of dyonic hairy black holes.

Pakistan

Askar Ali

Black holes of quartic quasitopological gravity, conformal scalar field and extended quasitopological electromagnetism

In this study, we proceed to investigate the Thurston geometries from the point of view of their Poisson-Lie (PL) T-dualizability. First of all, we find all subalgebras of Killing vectors that generate group of isometries acting freely and transitively on the three-dimensional target manifolds, where the Thurston metrics are defined. It is shown that three-dimensional Lie subalgebras are isomorphic to the Bianchi type algebras. We take the isometry subgroup of the metric as the first subgroup of Drinfeld double. In order to investigate the non-Abelian T-duality, the second subgroup must be chosen to be Abelian. Accordingly, the non-Abelian target space duals of these geometries are found via PL T-duality approach in the absence of <italic>B</italic>-field. We also comment on the conformal invariance conditions of the T-dual <italic>&#963;</italic>-models under consideration.