We present a comprehensive bottom-up analysis of lepton mass and mixing based on the non-holomorphic $A_{4}$ modular symmetry. Neutrinos are assumed to be Majorana particles, and the light neutrino masses are generated through the Weinberg operator. In this framework, we construct all phenomenologically viable models with minimal number of free parameters, with the Yukawa couplings expressed in terms of polyharmonic Maaß forms of weights $\pm4$ , $\pm2$ , and 0 at level $N=3$ . Without imposing generalized CP (gCP) symmetry, we identify 147 (six) viable models with eight real free parameters that successfully reproduce the current experimental data of the lepton sector for the normal (inverted) mass ordering. When gCP symmetry consistent with $A_{4}$ modular symmetry is included, the number of free parameters is reduced by one, yielding 47 (five) phenomenologically viable models in the normal (inverted) mass ordering. Finally, we present detailed numerical analyses of a representative model for both mass orderings to illustrate these results.

China

Xiang-Yan Gao

Cai-Chang Li

Minimal lepton models with non-holomorphic modular $\textit{A}$ $_{4}$ symmetry * Supported by Natural Science Basic Research Program of Shaanxi (2024JC-YBQN-0004) and the National Natural Science Foundation of China (12547106, 12247103)

The Schwinger effect, a non-perturbative mechanism for particle production in strong fields, plays a crucial role in understanding quantum vacuum decay and high-energy phenomena, including heavy-ion collisions (HIC). Although holographic quantum chromodynamics (QCD) models have been widely used to study this effect, most treatments assume isotropy or consider only a single type of anisotropy, neglecting the interplay between spatial and magnetic anisotropies that arise in realistic HIC scenarios. A unified framework accounting for both anisotropies is needed to accurately model particle production. We investigate the Schwinger effect in a twice anisotropic holographic QCD model incorporating both spatial and magnetic anisotropies. Using the anti-de Sitter/conformal field theory correspondence, we compute the total potential of a particle-antiparticle pair to quantify how these anisotropies influence pair production. Our results show that the magnetic field (parameterized by $c_B$ and $q_3$ ) enhances the Schwinger effect by lowering and narrowing the potential barrier, while increasing spatial anisotropy (controlled by $\nu$ ) suppresses the process by raising and widening the barrier. These findings demonstrate that magnetic and spatial anisotropies exert competing effects on particle production, emphasizing the necessity of treating both concurrently in holographic models. This work advances the theoretical description of the Schwinger effect in anisotropic environments, with implications for understanding non-equilibrium dynamics in HIC and other strongly coupled systems.

Wen-Bin Chang

Defu Hou

Schwinger effect in a twice anisotropic holographic model * Defu Hou's research is supported in part by the National Key Research and Development Program of China (2022YFA1604900). Additionally, Defu Hou receives partial support from the National Natural Science Foundation of China (NSFC) (12435009, 12275104). Wen-Bin Chang is supported by the Ph.D. Research Startup Project at Hubei Minzu University (RZ2500000857)

In this paper, we update constraints on the Holographic Dark Energy (HDE) model and the Interacting Holographic Dark Energy (IHDE) models in a non-flat universe, building upon our previous work in which the flat HDE and IHDE models were tested using same datasets, including DESI DR2 BAO, the five-year supernovae sample from DES, CMB distance priors, observational Hubble parameter data, and the local measurement of Hubble constant. Our results indicate that in the HDE model, an open universe is supported at $$6\sigma $$ , whereas in the IHDE models a closed universe is favored at over $$3\sigma $$ . The model parameter $\textit{c}$ is anti-correlated with $$H_0$$ in all these models, implying that a resolution to $$H_0$$ tension by reducing the parameter $\textit{c}$ comes at the expense of a Big Rip fate. Furthermore, using AIC, BIC, DIC, and Bayes evidence, we find that within the non-flat framework, the $$\Lambda $$ CDM model remains the most strongly supported by the data, while the HDE model is the most disfavored. Compared with the HDE model, the IHDE models demonstrate markedly improved agreement with the data, and the most strongly supported IHDE model is the one with the interaction term $$Q=3\beta H_{\textrm{0}}\frac{\rho _{\textrm{dm}}\rho _{\textrm{de}}}{\rho _{\textrm{dm}}+\rho _{\textrm{de}}}$$ .

Xiaofang Shen

Bing Xu

Kaituo Zhang

Xiangyun Fu

Qihong Huang

Liangliang Ren

Zelin Zhang

Updated observational constraints on interacting holographic dark energy models in a non-flat universe

In this work, we studied the Ayon-Beato Garcia (ABG) solution describing a nonsingular charged black hole using the moving-puncture method. As the first step, we obtained the BG solution in isotropic coordinates with a new, accurate numerical procedure. By focusing on the situation where there is at least one horizon, where the charge is smaller than or equal to a particular critical value, we show the transition between the wormhole geometry described by the isotropic solution to a time-independent trumpet foliation resulting from the disconnection of the two asymptotic regions of the wormhole geometry. The numerical experiments indicate that, as the charge approaches its critical value, the trumpet geometry approaches the extreme isotropic solution.

Brazil

Felipe Medeiros

H. Oliveira

Numerical experiments with a regular charged black hole

We derive a compact analytic formula for a complete basis of conformally invariant tensor structures for three-point functions of conserved operators in arbitrary 4D Lorentz representations. The construction follows directly from a novel constraint equivalent to applying conservation conditions at each point: the leading terms in all OPE limits appear as symmetric traceless tensors. We derive this by lifting to a unified SU($\textit{m}$, $\textit{m}$|2$\textit{n}$) analytic superspace framework, where the conservation conditions are automatically solved and then reducing back to 4D CFT. The same method is also used for cases involving one non-conserved operator. This formalism further reveals a map of the counting of CFT tensor structures to that of finite-dimensional SU(2$\textit{n}$) representations, solved by Littlewood-Richardson coefficients. All results can be directly re-interpreted as three-point $$ \mathcal{N} $$ = 2 and $$ \mathcal{N} $$ = 4 superconformal tensor structures via the unified analytic superspace.

United Kingdom

Paul Heslop

Hector Puerta-Ramisa

A compact formula for conserved three-point tensor structures in 4D CFT

We present a study of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ω</mi><mo stretchy="false">(</mo><mn>2380</mn><mo stretchy="false">)</mo></math> resonance and show that it is consistent with a dynamically generated state arising from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup><msup><mi mathvariant="normal">Ξ</mi><mo>*</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ω</mi><mi mathvariant="normal">Ω</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><mi mathvariant="normal">Ω</mi></math> interactions. In this picture, the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ω</mi><mo stretchy="false">(</mo><mn>2380</mn><mo stretchy="false">)</mo></math> is analogous to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ω</mi><mo stretchy="false">(</mo><mn>2012</mn><mo stretchy="false">)</mo></math>, which is generated from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><msup><mi mathvariant="normal">Ξ</mi><mo>*</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi><mi mathvariant="normal">Ω</mi></math> channels. The resulting mass, total width, and partial decay widths into the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><msup><mi mathvariant="normal">Ξ</mi><mo>*</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>*</mo></msup><mi mathvariant="normal">Ξ</mi></math> channels are compatible with the available experimental data. We also discuss possible experimental observables that could provide further insight into the nature of this state.

Yi-Yao Li

Albert Feijoo

Eulogio Oset

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ω</mi><mo stretchy="false">(</mo><mn>2380</mn><mo stretchy="false">)</mo></math> as a partner of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Ω</mi><mo stretchy="false">(</mo><mn>2012</mn><mo stretchy="false">)</mo></math>

We establish a new no-go theorem for cosmology: spatially flat (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi><mo>=</mo><mn>0</mn></math>) and open (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi><mo>=</mo><mo>−</mo><mn>1</mn></math>) Friedmann-Robertson-Walker (FRW) nonstatic spacetimes cannot be simultaneously nonsingular, geodesically complete, and consistent with the averaged null energy condition (ANEC). Equivalently, any dynamic flat or open universe that is complete must violate the ANEC. By contrast, closed universes (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi><mo>=</mo><mo>+</mo><mn>1</mn></math>) uniquely admit nonsingular, geodesically complete, ANEC-consistent solutions, with global de Sitter space as the canonical realization that saturates the ANEC. Furthermore, we analytically demonstrate that positive spatial curvature naturally mimics the phenomenology of phantom dark energy (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>w</mi><mo>&lt;</mo><mo>−</mo><mn>1</mn></math>), biasing flat-model reconstructions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>w</mi><mo stretchy="false">(</mo><mi>z</mi><mo stretchy="false">)</mo></math> at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>1</mn><mo>%</mo></math> level. These results sharpen the classical singularity theorems, establish a new classification of eternal cosmologies, and motivate renewed scrutiny of spatial curvature in both theory and observation.

Nathan L. Burwig

Damien A. Easson

Open case for a closed universe

In this work, we fix the leading term in the operator algebra of light-transformed operators in the context of flat space holography. Starting with light-transformed graviton correlators, we show that the OPE obtained by taking the collinear limit satisfies translation symmetry at the leading order not independently but with assistance from the sub-leading order. Motivated by this result, we start with a general CFT-like ansatz for the OPE and, by keeping track of the sub-leading term, derive an expression for the scaling dimension of the operator appearing in the leading term. We further show that we can fix the OPE coefficient corresponding to this term as well. We use this result to find the OPE for well-studied theories like gravity, Yang-Mills and Einstein-Yang-Mills theory, and find that the scaling dimension found from our formula matches with the one obtained by looking at the collinear limit of bulk momentum space vertices. We initiate a similar study for operators in the shadow basis by looking at the OPE of shadow-transformed graviton correlators.

India

Sourish Banerjee

Rudranil Basu

Light and shadow OPEs: a Carroll symmetric approach to flat holography

Recent theoretical analyses show that spin current can be induced by the baryon chemical potential gradient <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>∇</mi><msub><mi>μ</mi><mi>B</mi></msub></mrow></math> which becomes sizable in the fireballs created in heavy-ion collisions (HIC) at a beam energy of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi mathvariant="script">O</mi><mo>(</mo><mn>10</mn><mo>)</mo></mrow></math> GeV. This spin transport phenomenon can be considered as the cousin effect of the spin-Hall effect (SHE) in condensed matter systems with <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>∇</mi><msub><mi>μ</mi><mi>B</mi></msub></mrow></math> playing the role of the analogous electric field. In this letter, we study this important mechanism, which we call “baryonic SHE” or <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>∇</mi><msub><mi>μ</mi><mi>B</mi></msub></mrow></math>-induced polarization (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>∇</mi><msub><mi>μ</mi><mi>B</mi></msub></mrow></math>-IP), for differential spin polarization generation that has not been systematically explored before. We predict the signature of the baryonic SHE in HIC using a <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mn>3</mn><mo>+</mo><mn>1</mn><mo>)</mo><mi mathvariant="normal">D</mi></mrow></math> viscous hydrodynamic model MUSIC with a multiphase transport initial condition. We propose to use the second Fourier coefficients of the net spin polarization of Λ hyperon as sensitive probes for the baryonic SHE. Those baryonic SHE observables show a qualitative difference in sign and beam energy dependence for the situations with and without the baryonic SHE. Future experimental observation of these distinct qualitative features would provide strong evidence for the existence of this “baryonic SHE” in the hot and dense quantum chromodynamics matter.

Baochi Fu

Long-Gang Pang

Huichao Song

Yi Yin

Signatures of a baryonic spin-Hall effect in dense QCD matter

At hadron colliders, the net transverse momentum of particles that do not interact with the detector (missing transverse momentum, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math>) is a crucial observable in many analyses. In the standard model, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math> originates from neutrinos. Many beyond-the-standard-model particles, such as dark matter candidates, are also expected to leave the experimental apparatus undetected. This paper presents a novel deep neural network based <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math> estimator, deepmet, developed by the CMS Collaboration at the LHC. The deepmet algorithm produces a weight for each reconstructed particle based on its properties. The estimator is based on the negative vector sum of the weighted transverse momenta of all reconstructed particles in an event. Compared with other estimators currently employed by CMS, deepmet improves the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi>p</mi><mo stretchy="false">→</mo></mover><mi mathvariant="normal">T</mi><mrow><mi>miss</mi></mrow></msubsup></math> resolution by 10%–30%, shows improvement for a wide range of final states, is easier to train, and is more resilient against the effects of additional proton-proton interactions accompanying the collision of interest.