Bi-spinor and G-structure methods are used to classify the possible consistent truncations of type II supergravity to $\textit{d}$ = 6 Einstein-Maxwell (gauged) supergravity, and its consistent sub-sectors. In the absence of R-symmetry gauging and a tensor multiplet we establish that every supersymmetric Mink solution defines an embedding of the $\textit{d}$ = 6 theory. Adding a tensor multiplet places restrictions on these embeddings, but embeddings still exist. In the presence of R-symmetry gauging the internal spaces of the embeddings are neither related to Mink or AdS . Under the assumption that the internal space contains a single U(1) isometry housing the $\textit{d}$ = 6 gauge field we classify the possible embedding manifolds. We find two classes of embedding for the entire theory, one of which is governed by a Toda-like equation and contains at least one prototype bounded embedding, albeit containing likely un-physical singularities. In the absence of a tensor multiple the classes of embeddings become more permissive, though the PDEs governing them become more complicated in general.

Spain

Niall Macpherson

Ricardo Stuardo

Type II embeddings for $\textit{d}$ = 6 Einstein-Maxwell gauged supergravity

Japan

Rin Takada

Erratum: Electromagnetic leptogenesis — an EFT-consistent analysis via Wilson coefficients. Part II. Low-scale, resonant regime

This paper is a continuation of our earlier work, which aimed to develop methods for understanding the renormalization group of tensorial group field theories within the stochastic quantization framework. In that first study, we showed that the equations governing melonic structures, together with Ward identities, make it possible to close the hierarchy of flow equations, thereby reproducing the results of equilibrium theory. In the present work, we go further by extending the formalism to the out-of-equilibrium regime, while also examining the stability of dynamical equilibrium, specifically, potential violations of the fluctuation-dissipation theorem. Our objective here is purely methodological, and we focus on a simplified “toy” Abelian model that retains only the characteristic nonlocalities of group field theories.

France

Vincent Lahoche

Benin

Dine Ousmane Samary

Stochastic dynamics for group field theories. II. Methods for nonequilibrium renormalization group

Electroweak triplet Higgs sector extensions are well-motivated scenarios to address lepton flavor observations. These models can also be strongly constrained by combining precise, indirect low-energy measurements with direct searches for exotic, doubly-charged Higgs bosons. Together, these searches set competitive constraints on the type-II seesaw mechanism. In this work, we consider extensions of the type-II seesaw, specifically through the lens of a modified collider phenomenology. Surveying motivated extensions, we map out changes in expected correlations, focusing on the modified production and decay phenomenology of exotic Higgs particles. This enables us to assess the robustness of the type-II seesaw collider constraints against extended new-physics contributions that modify standard sensitivity expectations and projections.

United Kingdom

Christoph Englert

India

Manimala Mitra

Germany

Wrishik Naskar

Subham Saha

Robustness of type-II seesaw model collider searches

We provide a complete proof that Yang–Baxter bi-vector deformations are solution generating transformations in Type II supergravity. The proof does not rely on the assumption that the vielbein is invariant under Lie derivative along all Killing vectors entering the bi-vector. We analyse transformation of boundary terms and derive a simple expression for the case, when the boundary does not change its geometrical locus.

Russia

Igor Bogatyrev

Edvard Musaev

Timophey Petrov

Yang–Baxter symmetries of type II supergravity

We investigate the equilibrium structure of white dwarf stars in the Randall–Sundrum II braneworld scenario using the effective brane-TOV formulation, with the stellar matter described by the zero-temperature Chandrasekhar electron-degenerate equation of state at mean molecular weight per electron $$\mu _e = 2$$ . Scanning a range of brane tensions and Weyl-fluid closure parameters, we ask whether the braneworld corrections can support the super-Chandrasekhar masses ( $$\sim 2\,M_\odot $$ ) inferred for some over-luminous Type Ia supernova progenitors. To distinguish brane effects within the perturbative regime from formal extrapolations of the effective four-dimensional equations, we introduce a local, mass-based perturbativity diagnostic that compares the solution including the full Weyl evolution with the quadratic-correction-only solution at the same brane tension and central density. We do not compare against an independent non-perturbative five-dimensional solution – none currently exists in the literature for this configuration – but instead assess the perturbative admissibility of the solutions obtained after adopting the CAM closure. The general-relativistic limit is recovered with a Chandrasekhar mass of $$1.425\,M_\odot $$ , and within the perturbative-validity regime the maximum white dwarf mass is $$\simeq 1.50\,M_\odot $$ – about $$5\%$$ above this value and well below $$2\,M_\odot $$ . Masses approaching $$2\,M_\odot $$ arise only where the Weyl contribution is no longer perturbative. We conclude that, within the CAM-closed effective brane formulation and subject to the perturbative-validity criterion adopted here, RS-II braneworld corrections can mildly raise the Chandrasekhar mass scale but do not robustly support physical super-Chandrasekhar white dwarfs.

Saudi Arabia

M. Zeyauddin

White dwarf stars in Randall–Sundrum II braneworld gravity: perturbative bounds on super-chandrasekhar configurations

The idea of $\textit{reduction of couplings}$ provides a systematic procedure to search for relations among seemingly unrelated parameters of a renormalizable theory. As a consequence, such reduced theories exhibit more constrained parameter spaces. Motivated by this, in this work we perform a precise phenomenological analysis of the Higgs sector of a version of the Type-II 2HDM on which the idea of reduction of couplings has been applied. We compute Higgs boson masses and decay widths and confront them with current experimental measurements. Compared to the previous study, apart from the inclusion of actual experimental constraints on production and decay rates of Higgs bosons, we also included all model parameters in the RGE running as well as one- and two-loop threshold corrections and two-loop RGE running from the high scale. Furthermore, Higgs boson masses are now computed at the one-loop level. Top quark mass, which is an important prediction of the reduction framework, is now evaluated including previously missing sub-leading one-loop contributions, with an addition of up to four-loop pure-QCD corrections.

Poland

Wojciech Kotlarski

Portugal

Gregory Patellis

Phenomenology of the Higgs sector from reduction of couplings in the Type-II 2HDM

We investigate the equilibrium structure, static stability, and tidal deformability of neutron stars in the Randall–Sundrum II (RS-II) braneworld using the momentum-dependent interaction (MDI) hadronic equation-of-state family. The MDI sequence provides a controlled scan of the nuclear symmetry-energy slope <italic>L</italic> at fixed saturation properties. The brane-TOV formulation of Castro, Alloy, and Menezes [1] is adopted, together with a systematic scan of the Weyl-fluid closure parameter <italic>w</italic>. We find that increasing <italic>L</italic> and increasing the brane tension <italic>&#955;</italic> both shift neutron-star sequences toward larger radii and higher maximum masses, thereby producing a degeneracy in the mass&#8211;radius plane. Within the sampled Weyl-closure grid and the adopted massive-pulsar criterion, the sampled low-tension sector represented by <math altimg='si21.svg'><mrow><mi>&#955;</mi><mo linebreak='goodbreak'>=</mo><msup><mn>10</mn><mn>37</mn></msup><mspace width='0.16em' /><mrow><mrow><mi mathvariant='normal'>d</mi></mrow><mi>y</mi><mi>n</mi><mspace width='0.16em' /><mi>c</mi><msup><mi>m</mi><mrow><mo>&#8722;</mo><mn>2</mn></mrow></msup></mrow></mrow></math> is disfavoured for all four MDI members. The Weyl-parameter scan shows a clear tension-dependent asymmetry: at low brane tension, the stellar structure depends strongly on the closure choice, with |&#916; <italic>R</italic> <inf>1.4</inf>|/ <italic>R</italic> <inf>1.4</inf>&#8239;&#8771;&#8239;8&#8211;10%, whereas at <math altimg='si22.svg'><mrow><mi>&#955;</mi><mo linebreak='goodbreak'>=</mo><msup><mn>10</mn><mn>38</mn></msup><mspace width='0.16em' /><mrow><mrow><mi mathvariant='normal'>d</mi></mrow><mi>y</mi><mi>n</mi><mspace width='0.16em' /><mi>c</mi><msup><mi>m</mi><mrow><mo>&#8722;</mo><mn>2</mn></mrow></msup></mrow></mrow></math> the structural variation remains below 1%. Tidal deformabilities are computed within an effective-background braneworld approximation, in which the interior perturbation coefficients are constructed from the Castro effective density, pressure, and sound speed, while the exterior Love-number extraction is kept in the standard Schwarzschild form. In the accepted positive- <italic>k</italic> <inf>2</inf> Weyl subset, &#923; <inf>1.4</inf> varies by approximately 15&#8211;20%, even where the corresponding mass&#8211;radius variation is small. Adopting the GW170817 upper reference bound on the canonical tidal deformability, the softer MDI members are favoured within this discrete MDI family. These results indicate that tidal deformability provides a more sensitive diagnostic of the coupled ( <italic>L, &#955;, w</italic>) dependence than mass&#8211;radius information alone, while a closure-independent constraint on <italic>&#955;</italic> requires a denser brane-tension scan and a full Weyl exterior perturbation treatment.

Constraining the nuclear symmetry energy and brane tension with neutron-star tidal deformability in Randall–Sundrum II gravity

The Belle II measurement of the branching fraction for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>ν</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> shows a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.7</mn><mi>σ</mi></math> excess over the Standard Model prediction and motivates new-physics explanations such as axionlike particles, Higgs-like scalars, or beyond Standard Model gauge bosons. A two-body decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>X</mi></math> with an invisible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> provides a natural candidate explanation. This work provides a comprehensive test of this hypothesis using Belle II’s public model-agnostic likelihood. Posterior distributions are derived for the resonance mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>X</mi></msub></math> and the branching fraction, and a modified frequentist upper-limit mass scan is performed. The data favor a resonance with mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>X</mi></msub><mo>=</mo><msubsup><mn>2.1</mn><mrow><mo>−</mo><mn>0.1</mn></mrow><mrow><mo>+</mo><mn>0.2</mn></mrow></msubsup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and the product <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>X</mi><mo stretchy="false">)</mo><mo>·</mo><msub><mi mathvariant="script">P</mi><mrow><mi>X</mi><mo>,</mo><mi>inv</mi></mrow></msub><mo>=</mo><msubsup><mn>9.2</mn><mrow><mo>−</mo><mn>3.4</mn></mrow><mrow><mo>+</mo><mn>1.8</mn></mrow></msubsup><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">P</mi><mrow><mi>X</mi><mo>,</mo><mi>inv</mi></mrow></msub></math> is the probability that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> (and its decay products) are undetected. Bayes’s factors indicate a very strong preference for the Standard Model plus resonance over the Standard Model-only hypothesis. A frequentist likelihood-ratio test favors the Standard Model plus resonance hypothesis by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.0</mn><mi>σ</mi></math>. A light invisible resonance plus the Standard Model therefore provides a compelling description of the Belle II data.

Lorenz Gärtner

Nikolai Krug

Thomas Kuhr

Australia

Michael A. Schmidt

Slavomira Stefkova

Bruce Yabsley

Constraints on invisible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>X</mi></math> decays from the Belle II <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>ν</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> measurement

We study the late-time expansion history of the Universe within the VCDM model, a Type-II MMG realization that preserves the successes of General Relativity while extending beyond constant vacuum energy through a minimal Hamiltonian modification, generating a time-dependent vacuum sector without introducing additional degrees of freedom. We investigate this framework within a cosmographic approach by employing a Padé <italic>P</italic> <inf>(2,1)</inf> approximation for the Hubble parameter and luminosity distance, allowing the cosmographic parameters to be expressed directly in terms of the underlying VCDM model parameters and enabling a data-driven reconstruction of the expansion history. The model is constrained within a Bayesian framework using the MCMC technique, implemented via the affine-invariant ensemble sampler, with a joint analysis of cosmic chronometers, DESI BAO, and Type Ia supernova datasets (Union3, Pantheon+, and DESY5). We find that the model parameters are tightly constrained and consistent across different dataset combinations, with the jerk parameter remaining very close to its &#923;CDM value, <italic>j</italic> <inf>0</inf>&#8239;&#8771;&#8239;1, indicating no significant deviation at the level of higher-order cosmography. Furthermore, the transition feature previously reported in VCDM is not observed within the Pad&#233; <italic>P</italic> <inf>(2,1)</inf> cosmographic reconstruction, suggesting that it is not a robust requirement of current observational data but is sensitive to the choice of parametrization. Overall, our results indicate that the VCDM model effectively mimics &#923;CDM at the background level when constrained through a cosmographic approach, underscoring the importance of model-independent reconstructions in assessing alternative cosmological scenarios.

Soumya Kanta Bhoi

Sai Swagat Mishra

P.K. Sahoo

Kinematic probes of Type-II MMG: Padé cosmographic analysis of VCDM