We compare the fixed-order NLO QCD predictions for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi><mo stretchy="false">→</mo><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mo>+</mo><mi>X</mi></math> process in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mo>ℓ</mo></math> decay channel with the parton-shower-based results obtained with the powheg and mc@nlo matching methods. In the first case, NLO QCD corrections are consistently included in both the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover></math> production step and the decays of the four top quarks, preserving all spin correlations. In the second approach, higher-order effects in top-quark decays with approximate spin correlations are simulated in the pythia parton-shower framework. Additionally, we analyze the impact of including the so-called matrix element corrections in top-quark decays in both parton-shower matched predictions. The comparison is performed at the integrated and differential fiducial cross-section level for the LHC center-of-mass energy of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13.6</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>.

Germany

Manal Alsairafi

Nikolaos Dimitrakopoulos

Malgorzata Worek

Modeling top-quark decays in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>t</mi><mover accent="true"><mrow><mi>t</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mi>t</mi><mover accent="true"><mrow><mi>t</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math> production at the LHC

Domain wall (DW) networks may have formed in the early Universe following the spontaneous breaking of a discrete symmetry. Notably, several particle physics models predict the existence of current-carrying DWs, which can capture and store particles as zero modes on it. In this study, we demonstrate that gravitational waves (GWs) generated by current-carrying DWs with fermionic zeromodes exhibit a novel feature: an additional peak with a distinct spectral shape in the GW spectrum resembling mountains, arising from metastable topological remnants, which we term “spherons.” This distinct signature could be detectable in upcoming GW observatories such as LISA. The results suggest that DW networks in beyond Standard Model scenarios could emit GW signals that are significantly stronger and with greater detectability than previously expected.

Poland

Anish Ghoshal

Japan

Yu Hamada

Gravitational waves created by current-carrying domain walls

We formulate a light-front model for the pion that explicitly incorporates the gluonic degree of freedom. In this framework, high-energy scattering off the pion is described by an active gluon, while the remaining constituents are treated as a spectator system with an effective mass. The mass spectrum and light-front wave functions (LFWFs) of the pion are determined by solving two Schrödinger-like equations derived from quantum chromodynamics: the light-front holographic equation in the chiral limit and the ’t Hooft equation. Using the resulting LFWFs, we compute the gluon distributions within pion, including the parton distribution functions in comparison with the available global fits, generalized parton distributions, and transverse momentum-dependent distributions. The present analysis is restricted to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi domain of the pion’s gluon generalized parton distribution, without explicit construction of the Efremov-Radyushkin-Brodsky-Lepage region. Consequently, the polynomiality condition for full Mellin moments is not satisfied by construction. Furthermore, we demonstrate that the obtained LFWFs provide a good description of the gravitational form factors of pion when compared with the recent lattice QCD results.

China

Satvir Kaur

Chandan Mondal

Gluon distributions in the pion

In this paper, we utilize the maximum entropy prescription to determine a quantum state of a small collision system at the kinetic freeze-out. We derive expressions for multiplicity-selected particle momentum spectra and correlation functions by applying a fixed particle number constraint to this state. The results of our analysis can be useful for interpreting the multiplicity dependence of the particle momentum spectra and correlations in high-multiplicity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collision events at a fixed LHC energy.

Ukraine

S.V. Akkelin

Particle momentum spectra, correlations, and maximum entropy principle in high-multiplicity collision events

We establish direct evidence for the perturbative distinguishability between black hole microstates and thermal states using the AdS/CFT correspondence. In two-dimensional holographic conformal field theories, we obtain the subsystem fidelity and quantum Jensen-Shannon divergence, both of which provide rigorous lower and upper bounds for subsystem trace distance. This result demonstrates that perturbative quantum gravity corrections break semiclassical indistinguishability, thereby supporting the recovery of information even from a small amount of the Hawking radiation.

Jiaju Zhang

Perturbative distinguishability of black hole microstates from AdS/CFT correspondence

To resolve ambiguities from multiple solutions in experimental measurements, we construct a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>χ</mi><mn>2</mn></msup></math> function incorporating constraints such as isospin conservation and amplitude relations. By minimizing the global <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>χ</mi><mn>2</mn></msup></math>, we identify physical solutions for seven hidden-charm decay channels of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4230</mn><mo stretchy="false">)</mo></math>. Crucially, the physical solution for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4230</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mi>J</mi><mo>/</mo><mi>ψ</mi></math> corresponds to the largest among four experimental solutions, potentially modifying inputs for theoretical calculations. Additionally, we predict <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Γ</mi><mrow><mi>e</mi><mi>e</mi></mrow></msub><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>Y</mi><mo stretchy="false">(</mo><mn>4230</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>ψ</mi><mo>′</mo></msup><mo stretchy="false">)</mo></math> based on our results, acknowledging substantial uncertainties in current measurements.

Jie Yuan

Yadi Wang

Kai Zhu

Pinpointing physical solutions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4230</mn><mo stretchy="false">)</mo></math> decays

Motivated by the work of Longhi and Materassi, who constructed a realization of the (centerless) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra for the massive Klein-Gordon field in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mo>+</mo><mn>1</mn></math> dimensions, we build a realization of the (centerless) massless <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra including superrotations. This realization depends only on the momenta in the light cone expressed in celestial coordinates without any reference to the Klein-Gordon field. The quadratic Casimir of the Lorentz algebra is written in terms of a second order differential operator and the volume form plays an essential role in this construction. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra in terms of vector fields shows its kinematical nature, like the Poincaré algebra. We also construct a dynamical realization of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> from the symplectic structure on the solutions of the massless four-dimensional Klein-Gordon field in terms of quadratic expressions of the Fourier modes and plane waves invariant under translations. Using the Mellin transform, we rewrite the Klein-Gordon field in terms of the boost invariant basis, and write down the corresponding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> realization. We also provide the relation with spherical harmonics, linking our results with the solutions of Longhi-Materassi, which are in fact a subset of ours.

Spain

Carles Batlle

Italy

Roberto Casalbuoni

Daniele Dominici

United Kingdom

José Figueroa-O’Farrill

Joaquim Gomis

Celestial kinematical interpretation for an extended <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra

We analyze the spectra of general nonminimal second-order operators. To do this, we derive the local part of the trace of the second Seeley-DeWitt heat kernel coefficient for such operators in a completely model-independent way. Afterwards, we provide three examples to show how our result can be applied in practical scenarios. In particular, we emphasize this discussion when dealing with a toy model of dynamical torsion, which is viewed as a simple instance of higher-spin fields. All our results are compatible with the literature, and we provide a Mathematica notebook with the model-independent results that are written in the paper.

Dario Sauro

Heat kernel of nonminimal second-order operators

We study the chiral symmetry breaking effects of helical magnetic fields in a simple bottom up AdS/CFT model. We explore the instability of the chirally symmetric solution in the presence of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> field and see how it switches off as the wave vector of the helix, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi></math>, rises, resulting in a first order transition. At low energies the model averages over the helix and the magnetic field is not seen. We show that other sources of chiral symmetry breaking are not directly affected by the helical <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> field. We provide examples of both magnetic catalysis and inverse magnetic catalysis which switch off at large <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi></math>.

Nick Evans

Wanxiang Fan

Chiral symmetry restoration for helical magnetic fields in holography

In this paper, we identify a novel topological subclass, dubbed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>W</mi><mo stretchy="false">˜</mo></mover><mrow><mn>1</mn><mo>+</mo></mrow></msup></math>, in the thermodynamics of higher odd-dimensional, multiply rotating Kerr anti–de Sitter (AdS) black holes. This discovery extends the established topological classification beyond the five classes and two subclasses previously known. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>W</mi><mo stretchy="false">˜</mo></mover><mrow><mn>1</mn><mo>+</mo></mrow></msup></math> subclass exhibits a unique and previously unreported stability profile: it admits a thermodynamically stable small black hole state in the low-temperature limit, while in the high-temperature limit, the phase space simultaneously contains one stable large black hole, one stable small black hole, and one unstable small black hole state. Our analysis, which treats black hole solutions as topological defects, reveals a richer landscape of black hole thermodynamics than previously understood and necessitates an expansion of the topological classification scheme to accommodate this new phenomenology.

Wangyu Ai

Di Wu

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>W</mi><mo stretchy="false">˜</mo></mover><mrow><mn>1</mn><mo>+</mo></mrow></msup></math> subclass: Extending the topological classification of black hole thermodynamics