We investigate the connection between entanglement entropy and the notion of irreversibility in the renormalization-group flow in the context of a simple theory for which an explicit calculation from first principles is feasible. The change of the entanglement entropy for a spherical entangling surface as its radius grows from zero to infinity corresponds to the flow from the UV to the IR. Through analytical and numerical means, we compute the entanglement entropy for a free massive scalar theory, making use of the method of correlation functions. We deduce a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi></math>-function in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mo>+</mo><mn>1</mn></math> dimensions and an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>a</mi></math>-function in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mo>+</mo><mn>1</mn></math> dimensions. Both functions are monotonic and vary continuously between one and zero, which are the expected values for this theory.

Greece

Konstantinos Boutivas

Dimitrios Katsinis

Georgios Pastras

Nikolaos Tetradis

Computing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi></math>- and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>a</mi></math>-functions from entanglement

We propose a cogenesis scenario in which both the baryon asymmetry and dark matter abundance originate from the kinetic misalignment of the QCD axion. The framework unifies the Peccei-Quinn (PQ) mechanism with a type I seesaw sector, where Hubble-induced masses and higher-dimensional PQ-violating operators drive early time axion rotation. Working within the Dine-Fischler-Srednicki-Zhitnitsky axion model augmented by heavy neutrinos, we identify the parametric window of right-handed neutrino masses, determined by its decay rate, and the range of Hubble scales compatible with successful cogenesis, while maintaining the axion solution to the strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> problem and satisfying current limits on axion isocurvature perturbations. Our results establish kinetic misalignment as a robust and predictive mechanism for the QCD-axion cogenesis, leading to correlated constraints on the right-handed neutrino mass and the inflation scale for an axion decay constant within the viable range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>8</mn></mrow></msup><mi>–</mi><msup><mrow><mn>10</mn></mrow><mrow><mn>12</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>.

South Korea

Eung Jin Chun

Spontaneous cogenesis by the QCD axion in a type I seesaw mechanism

We analyze the effective couplings of a light, spinless, gauge-singlet particle $\textit{ϕ}$ to on-shell photons. Starting from the most general theory at the electroweak scale, which allows for CP-violating interactions suppressed by inverse powers of an ultraviolet scale Λ, we derive the corresponding low-energy effective theory valid below the GeV scale. Within this framework, we systematically expand the effective couplings of $\textit{ϕ}$ to on-shell photons in powers of small parameters. Working at the one-loop level, we retain terms at first order in 1$\textit{/}$Λ. We incorporate both isospin-breaking effects and $\textit{η}$–$\textit{η′}$ mixing, and provide explicit expressions for the couplings up to first order in $$ {m}_{\phi}^2/{m}_{\eta}^2 $$ and $$ {m}_{\pi}^2/{m}_{\eta}^2 $$ . As applications, we compute the decay rate of $\textit{ϕ}$ into two photons and illustrate our results in several physically motivated scenarios.

Italy

Ferruccio Feruglio

Switzerland

Gabriele Levati

Germany

Robert Ziegler

On the decay of a light spinless particle into two photons

A covariant implementation of diffeomorphisms in the presence of local symmetries is a nontrivial aspect of gravitational theories. In Double Field Theory, this is achieved through the so-called generalized Kosmann derivative. In this work, we show that the generalized Kosmann derivative admits a natural formulation entirely in terms of generalized fluxes through the inclusion of a compensating term that plays the role of a generalized momentum map, yielding a fully determined and covariant operator that provides a covariant realization of generalized diffeomorphisms. When parameterized in terms of the field content of heterotic supergravity, the resulting symmetry transformations give rise to momentum maps at the supergravity level, offering a duality-covariant interpretation of these objects. This framework provides a natural setting for the construction of conserved currents and Noether charges in doubled geometry with internal symmetries, with direct implications for black hole thermodynamics and its higher-derivative corrections in a duality-covariant setting.

Chile

Romina Ballesteros

Poland

Eric Lescano

Argentina

Jesús Rodríguez

Kosmann derivative and momentum maps from a duality covariant framework

We provide a detailed derivation of the Schwarzian modes in the full geometry of the Bañados-Teitelboim-Zanelli (BTZ) black hole at finite temperature, establishing the precise conditions under which they emerge from the general solution, thereby clarifying the absence of rotational modes in the full geometry. In addition, we demonstrate that the same modes can be recovered through a purely geometric Kerr-Schild construction. This equivalent approach offers a new geometric understanding of the Schwarzian sector and highlights the correspondence between perturbative and pure geometric approaches, additionally it provides a connection with double copy.

Lucas Acito

Matías Sempé

From BTZ perturbations to Schwarzian modes: a geometrical and perturbative analysis

We consider Loryons, particles beyond the Standard Model that receive a significant fraction of their masses from electroweak symmetry breaking, in the context of a two Higgs doublet model. Using scalar Loryons in the [1, 1], [1, 3] (as well as the equivalent [3, 1]) and the [2, 2] representations of the custodial SU(2) × SU(2) global symmetry as benchmarks, we study the constraints on the Loryon parameter space, focusing on unitarity, Higgs decay observables, and the absence of Loryon vacuum expectation values. We find that while neutral singlet Loryons remain viable for masses up to 700 GeV, representations containing charged scalars are severely constrained by LHC data, particularly as the fraction of mass generated by symmetry breaking increases.

United States

Can Kilic

Sanjay Mathai

Taewook Youn

Constraints on Loryons in a two Higgs doublet model

The rapid cooling of the neutron star in Cassiopeia A is speculated to arise from an enhanced neutrino emission caused by the onset of 3 <italic>P</italic> <inf>2</inf>-wave neutron superfluidity in the core. However, the neutrino emissivity due to Cooper-pair breaking and formation is in tension with the requirements for explaining the observed cooling rate. Here, we show that such a rapid cooling can be explained once the non-Fermi liquid behavior of the non-superfluid neutron liquid induced by superfluid quantum criticality is included into the theoretical description of neutron star cooling, without assuming the existence of additional energy loss processes. Our results indicate that the neutron star in Cassiopeia A remains in the thermal relaxation stage, which is greatly prolonged by the non-Fermi liquid behavior. The good agreement between our theoretical results and recent observational cooling data points to the pivotal role played by superfluid quantum criticality in neutron stars.

China

Hao-Fu Zhu

Guo-Zhu Liu

Xufen Wu

Rapid cooling of the Cassiopeia A neutron star due to superfluid quantum criticality

We propose a Quantum Spectral Curve for planar string theory on AdS ×S ×S ×S supported by pure Ramond-Ramond flux. Our proposal is built on symmetry considerations and integrability-based functional relations. To test our construction, we consider the large volume limit and successfully reproduce the crossing equations and the correct structure of the Bethe equations found in the literature. In a symmetric subsector, we find agreement with previously known results and furthermore extend the Asymptotic Bethe Ansatz to include massless modes. Beyond this sector, we identify an interesting puzzle regarding the compatibility of crossing equations with braiding unitarity for individual dressing phases, which warrants further investigation and may require additional physical insights or novel structures not previously encountered in related systems. As we expect the QSC to be exact in the planar limit, our proposal may open the way for non-perturbative analysis of this holographic system.

United Kingdom

Filipp Chernikov

Sweden

Simon Ekhammar

Nikolay Gromov

Benjamin Smith

Gluing Quantum Spectral Curves: a two-copy $$ \mathfrak{osp}\left(4|2\right) $$ construction

We explore the phenomenological consequences of non-minimal hidden sector interactions on observable correlations in the Higgs sector, mediated through the ℤ -symmetric Higgs portal. Particular attention is given to non-standard momentum dependencies of the hidden sector scalar, which arise naturally in an effective field theory (EFT) framework, e.g. in Composite Scalar Dark Matter theories. We discuss the implications of such hidden sector interactions for the thermal history of the universe. We show that aspects of such non-standard momentum dependencies can be probed at future lepton colliders such as a FCC-ee, potentially also through radiative corrections. This gives rise to precision probes for regions where direct detection constraints and relic abundance can be accounted for as predicted in, e.g., Composite Scalar Dark Matter theories.

 Anisha

Lisa Biermann

Christoph Englert

Margarete Mühlleitner

Phenomenology of a kinetic Higgs portal

We develop a manifest supertwistor space formalism for three dimensional $$ \mathcal{N}=1,2,3,4 $$ superconformal field theories. This formalism simultaneously makes manifest the supersymmetry, conformal invariance and conservation. We solve two and three point correlators of (half) integer spin conserved supercurrents using the graded supergroup generators. Apart from the superconformal generators, we find that the superhelicity operators are necessary to fix their functional form in this setup. The superhelicity operators can be recast into first order Euler equations which besides the standard rational solutions, also admit weak solutions that are distributional in nature. They play an important role in the case of three point functions, where the supercorrelator takes the form of a product of delta functions. Interestingly, we find that these supercorrelators are extremely simple, elegant and uniform for all spins and for all $$ \mathcal{N}\le 4 $$ , which resemble the non supersymmetric correlators where the twistors are replaced with appropriately defined supertwistors.

India

Aswini Bala

Sachin Jain

Dhruva K. S.

Deep Mazumdar

Vibhor Singh

Brijesh Thakkar

A supertwistor formalism for $$ \mathcal{N}=1,2,3,4 $$ SCFT3