We report stronger evidence for the $X(7200)$ state and markedly improved measurements of the $X(6900)$ resonance parameters based on a combined analysis of the di- $J/\psi$ mass spectrum using published data from LHCb, ATLAS, and CMS. Through simultaneous fits to the datasets from all three experiments, we observe the $X(6900)$ with overwhelming significance ( $ \gt 12\sigma$ ) and determine its mass and width with improved precision. For the $X(7200)$ , we find consistent signals across multiple interference models, with significances ranging from $3.7\sigma$ to $6.6\sigma$ ; in the best-fit model (the CMS three-resonance scheme), the significance reaches $6.6\sigma$ , providing substantially stronger evidence for this state. Our results underscore the essential role of interference effects in fully charmed tetraquark spectroscopy and offer new constraints on their production mechanisms at the LHC.

China

Yuan Wang

Ran Li

Bin Zhong

Ya-Qian Wang

Enhanced evidence of $\textit{X}$(7200) and improved measurements of $\textit{X}$(6900) parameters from a combined LHCb-ATLAS-CMS analysis * Supported by the National Natural Science Foundation of China (NSFC) (12475077)

We investigate a bosonic system within an effective quantum field theory defined on a non-trivial topology in the presence of an external magnetic field. Using the proper-time formalism in the one-loop approximation, we obtain thermal, density, and finite-volume corrections to the effective Lagrangian under spatial confinement. We also analyze the effects of topology and boundary conditions on the system magnetization. Periodic boundary conditions lead to diamagnetic behavior, while antiperiodic boundary conditions induce paramagnetism for the same fixed parameters. Twisted boundary conditions exhibit an intermediate behavior. The analysis is performed within an approximate implementation of the boundary condition in the $$x$$ -direction, where the explicit $$y$$ -dependence of the corresponding transition function is neglected. Consequently, the numerical investigation is not restricted to exactly flux-quantized torus configurations. In all cases considered, the external magnetic field induces a monotonic enhancement of the magnetization intensity. In the zero-temperature and infinite-volume limits, our results recover Schwinger’s expression for a spinless quantum field in an external magnetic field.

Brazil

Emerson Corrêa

Michelli Sarges

Airton Rodrigues

Carlos Bahia

Effective Lagrangian of a bosonic system in a non-trivial topology under magnetic effects

The microphysics underlying nonbaryonic dark matter remains unknown. I derive the two-species Schrödinger-Poisson-Yukawa system for spin-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mn>1</mn><mn>2</mn></mfrac></math> dark-sector fermion fields, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> (mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>1</mn></msub></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>χ</mi></math> (mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>2</mn></msub></math>), coupled through a scalar mediator of mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>ϕ</mi></msub></math> via a universal Yukawa coupling, within an orbital-free density-functional framework with the Kirzhnits gradient coefficient <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>λ</mi><mi mathvariant="normal">B</mi></msub><mo>=</mo><mn>1</mn><mo>/</mo><mn>9</mn></math>. A central result is that the Bohm potential, far from being negligible in the Thomas-Fermi regime, contributes a species-dependent surface-energy correction analogous to the nuclear liquid-drop model; the heavier fermion species generates an outward quantum-pressure wall whilst the lighter species provides an inward surface tension, with degeneracy pressure furnishing the bulk confinement. In the single-species Schrödinger-Poisson limit the ground state recovers the benchmarked invariants <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><mi>dim</mi></msub><mo>≃</mo><mn>3.883</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>x</mi><mi>T</mi></msub><mo>≃</mo><mn>2.562</mn></math>, yielding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>M</mi><msub><mi>R</mi><mi>T</mi></msub><mo>≃</mo><mn>9.95</mn><msub><mi>λ</mi><mi mathvariant="normal">B</mi></msub><msup><mi>ℏ</mi><mn>2</mn></msup><mo>/</mo><mo stretchy="false">(</mo><mi>G</mi><msubsup><mi>m</mi><mn>1</mn><mn>2</mn></msubsup><mo stretchy="false">)</mo></math>. For polytropic index <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mo>=</mo><mn>5</mn><mo>/</mo><mn>3</mn></math> the mass-radius relation satisfies <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi><mo>∝</mo><msup><mi>M</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>3</mn></mrow></msup></math>; for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mo>=</mo><mn>4</mn><mo>/</mo><mn>3</mn></math> a limiting mass emerges above which no stable equilibrium exists. Illustrative configurations span <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>M</mi><mo>=</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup><mi>–</mi><mn>5</mn><msub><mi>M</mi><mo stretchy="false">⊙</mo></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>1</mn></msub><mo>∼</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, and radii from a few km to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><msup><mn>10</mn><mn>3</mn></msup><msub><mi>R</mi><mo stretchy="false">⊙</mo></msub></math>, with gravitational-wave contact frequencies in the Einstein Telescope and LISA bands and microlensing signatures accessible to current surveys. The predictive rigidity of the resulting mass-radius relation, in which the single microphysical parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>1</mn></msub></math> determines the equilibrium radius once the total mass is specified, furnishes a reproducible, first-principles reference for constraining the dark-fermion mass in multicomponent dark sectors.

Portugal

Ilídio Lopes

Self-gravitating quantum stars with a globally relevant Bohm potential

Jet quenching is a phenomenon in heavy-ion collisions arising from jet interactions with the quark-gluon plasma (QGP). Its study is complicated by the interplay of multiple physics processes that affect jet observables. In addition, detector effects may influence the results and must be accounted for when identifying quenched jets. We employ a Long Short-Term Memory (LSTM) neural network trained on jet substructure, incorporating parton shower history, to predict jet-by-jet quenching levels. Using photon-jet samples from the J event generator, we show that the LSTM predictions strongly correlate with true jet energy loss. This validates that the model effectively learns the features of jet-QGP interaction. We simulate detector effects using D simulation framework and demonstrate that the method identifies quenching effects in a realistic environment. We test the approach with photon-jet momentum imbalance, jet fragmentation function, and jet shape, which were not included in the training, confirming its ability to distinguish true quenching features.

United States

Yilun Wu

Yi Chen

Julia Velkovska

Validating a machine learning approach to identify quenched jets in heavy-ion collisions

Electroweak precision tests, expressed through the oblique parameters <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>, impose stringent constraints on physics beyond the Standard Model. Gauge extensions of the Standard Model based on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo>×</mo><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mi>N</mi></msub></math> symmetry predict a rich scalar and gauge spectrum that contribute to these parameters. Previous studies have shown that 3-3-1 gauge bosons give negligible contributions to the oblique parameters, while the contributions of the scalar sector to these parameters have received comparatively little attention. In particular, for the version of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo>×</mo><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mi>N</mi></msub></math> model with right-handed neutrinos, the impact of the scalar sector on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math> has not yet been addressed. In this work, we fill this gap and address systematically the scalar contributions to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math> within this version. As main result, we show that the parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math> puts stringent constraints on the masses and energy scales associated to the spectrum of scalars of the model.

A. Doff

C.A. de S. Pires

Scalar contributions to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>S</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>T</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>U</mi></mrow></math> parameters in a 3-3-1 model

We investigate how the curvature of the freeze-out hypersurface polarizes massive vector bosons in relativistic heavy-ion collisions. Starting from the Proca Lagrangian and using the Wigner function formalism, we perform a systematic gradient expansion to obtain a covariant spin-polarization tensor expressed in terms of hydrodynamic fields and the curvature tensor of the freeze-out hypersurface. Analytic results for Bjorken and Gubser flows show that curvature anisotropy generates a nonzero tensor polarization. For <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi></math> meson, we estimate the curvature contribution to its spin alignment as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>δ</mi><msub><mi mathvariant="normal">Θ</mi><mrow><mi>y</mi><mi>y</mi></mrow></msub><mo>∼</mo><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math>. We also find that the curvature contribution grows as the system size decreases. A rough estimate for central O-O collisions gives a spin alignment of order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup></math>, suggesting that spin-alignment measurements in such small systems may provide a clean probe of this geometric effect.

Zhong-Hua Zhang

Xu-Guang Huang

Tensor spin polarization induced by a curved freeze-out hypersurface

We investigate the spectrum of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi mathvariant="normal">ϒ</mi><mi mathvariant="normal">ϒ</mi></mrow></msub></mrow></math> tetraquark candidates within a coupled-channel framework. The analysis includes all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>L</mi><mo>≤</mo><mn>2</mn></math> combinations of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mi>P</mi></msup><mo>=</mo><msup><mn>0</mn><mo>±</mo></msup><mo>,</mo><msup><mn>1</mn><mo>±</mo></msup><mo>,</mo><msup><mn>2</mn><mo>±</mo></msup></math> sectors. The meson-meson interaction is derived from an underlying constituent quark model through the resonating group method, and the properties of the states are obtained from poles of the scattering matrix. We find a rich spectrum of resonant, and virtual, states distributed between the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> thresholds. The pattern of poles exhibits approximate heavy-quark spin symmetry multiplets. Several states are dominated by a single channel and can be associated with threshold-driven structures, while higher-mass resonances show sizable mixing among channels involving radially excited bottomonia. The predicted widths range from tens to several hundred MeV. Branching ratios indicate that many states couple predominantly to final states with at least one excited bottomonium, whereas only a subset of the spectrum is expected to be visible in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math> channels. These results provide quantitative guidance for experimental searches of fully heavy tetraquarks and offer a test of coupled-channel dynamics and heavy-quark spin symmetry in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> sector.

Spain

P.G. Ortega

D.R. Entem

F. Fernández

J. Segovia

Exploring <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi mathvariant="normal">ϒ</mi><mi mathvariant="normal">ϒ</mi></mrow></msub></math> tetraquark candidates in a coupled-channels formalism

We propose a radiatively induced lepton mass model introducing a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math> gauging <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mn>5</mn></msub></math> fusion rule. In our framework, the charged-lepton mass matrix is generated at one-loop level via dynamical breaking of the fusion rule. On the other hand, the neutrino mass matrix is induced at the one-loop level without breaking the fusion rule. As a direct consequence of the loop induced charged lepton masses, we can also consider lepton flavor violations, electron and muon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math>, and charged-lepton electric dipole moments that come into our valid phenomenological discussion. Then, we perform numerical analysis and show some interesting tendency on the Dirac <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> phase, two Majorana phases, charged-lepton electric dipole moments and the neutrinoless double beta decay, all of which depends on their arguments where we fix the absolute values of our free parameters in order to satisfy experimental data of the lepton masses and mixing angles.

Takaaki Nomura

Hiroshi Okada

Yoshihiro Shigekami

Radiative lepton model in a noninvertible fusion rule

Within the framework of Lanzhou quantum molecular dynamics transport model, the production of deuteron, triton, 3He, and <italic>&#945;</italic> in collisions of 132Sn + 124Sn, 124Sn + 124Sn and 108Sn + 112Sn at 270 <italic>A</italic> MeV has been systematically investigated with a kinetic approach. It is demonstrated that the cluster production is correlated with the binding energy cluster potential, Mott effect etc, and the larger yields of deuteron and <italic>&#945;</italic> in comparison with the triton and 3He production. The mid-rapidity slope parameters of directed flows in the isotopic reactions increase with the mass number of cluster. The out-of-plane emission of protons is dominant in comparison with the cluster production and manifests the cluster formation at the compression stage in nuclear collisions. The emission timescale of clusters is correlated with the cluster formation in the cascade collisions and transportation in nuclear medium.

Yuan-Qing Guo

Ban Zhang

Si-Min Chen

Hui-Gan Cheng

Ya-Peng Zhang

Zhi-Gang Xiao

Zhao-Qing Feng

Collective flows of clusters in the isotopic nuclear reactions with a kinetic approach

Blazars are a class of active galactic nuclei, supermassive black holes located at the centres of distant galaxies characterised by strong emission across the entire electromagnetic spectrum, from radio waves to gamma rays. Their relativistic jets, closely aligned to the line of sight from Earth, are a rich and complex environment, characterised by the presence of strong magnetic fields over parsec-scale lengths. Owing to their cosmological distance from Earth, these sources serve as ideal targets to probe non-standard gamma-ray propagation. In particular, axion-like particles (ALPs) could be detected through their coupling to photons, which enables ALP-photon conversions in external magnetic fields, leading to distinct signatures in the blazars’ gamma-ray spectra. In this work, we estimate the potential of the Cherenkov Telescope Array Observatory (CTAO) to constrain the ALP parameter space by simulating observations of two bright blazars, Mrk 501 and PKS 2155−304. We obtain projected $$2\sigma $$ exclusion regions, demonstrating that CTAO will be able to consistently improve present limits thanks to its greater energy resolution and point-source sensitivity with respect to present ground-based gamma-ray telescopes. In addition to the standard statistical technique based on the likelihood ratio test, we further demonstrate the application of a new method based on machine learning classifiers, which may help in reducing the effect of systematic model-dependent uncertainties in future ALP searches.

Italy

F. Schiavone

L. Di Venere

F. Giordano

Projected sensitivity of CTAO to axion-like particles from blazars with a machine learning approach