<p>The <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>T</mi></mrow></math> matrix of the heavy quark-antiquark (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Q</mi><mover accent="true"><mi>Q</mi><mo>¯</mo></mover><mspace width="0.28em"></mspace></mrow></math>) pair interacting through a screened Cornell potential in the quark-gluon plasma is computed without employing the partial-wave expansion. This is compared with the results obtained using the conventional method of partial-wave expansion. Through a comprehensive survey over a range of screening mass and center-of-mass (c.m.) energy, which, when combined, determine the orbital angular momentum involved in the scattering, it is demonstrated that a substantial number of partial-wave terms are necessary to precisely match the full scattering amplitude directly obtained from the method without partial-wave expansion. For moderate screening masses (corresponding to one to two times the crossover transition temperature) and c.m. energy, the number of partial waves required for satisfactory matching turns out as large as 10–20, substantially larger than what one would expect based on simply measuring the magnitudes of the first few partial-wave amplitudes. This highlights the efficacy and advantage of the new method in directly obtaining the full scattering amplitude needed for further computation of physical observables, which is illustrated by comparing the calculations of heavy quark-antiquark scattering cross section and heavy quark drag coefficient between the two methods. We also employ the new method to calculate the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>T</mi></mrow></math> matrix at c.m. energies below the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Q</mi><mover accent="true"><mi>Q</mi><mo>¯</mo></mover><mspace width="0.28em"></mspace></mrow></math>mass threshold, and demonstrate the presence of bound states of different orbital quantum numbers simultaneously in a single energy scan.</p>

Anurag Tiwari

Min He

In-medium heavy quark-antiquark <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>T</mi></math> matrix without partial-wave expansion

<p>The first four-dimensional amplitude analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mo>+</mo></msup></math> decay is performed with proton-proton collision data collected by the LHCb experiment at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>5.4</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">f</mi><msup><mrow><mi mathvariant="normal">b</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math>. The data cannot be fully explained by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>K</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup></math> contributions alone. A significantly better description of the data is obtained by adding a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></mrow><mo>+</mo></msubsup></math> contribution decaying to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>π</mi><mo>+</mo></msup></math>. The properties of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></mrow><mo>+</mo></msubsup></math> structure are consistent with the exotic state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> reported in the isospin-related <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>K</mi><mo>−</mo></msup><msup><mi>π</mi><mo>+</mo></msup></math> decay. Effects of a possible <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup><mo stretchy="false">→</mo><msubsup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mn>1</mn><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>2600</mn><msup><mo stretchy="false">)</mo><mn>0</mn></msup><msup><mi>D</mi><mo>+</mo></msup></math> decay mode on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msup><mi>π</mi><mo>+</mo></msup></math> mass distribution are investigated through a Flatté parametrization, providing constraints on the relative decay strength. A description of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> structure using the triangle singularity mechanism is studied and also found to be consistent with the data.</p>

R. Aaij

A.S.W. Abdelmotteleb

C. Abellan Beteta

F. Abudinén

T. Ackernley

A.A. Adefisoye

B. Adeva

M. Adinolfi

P. Adlarson

C. Agapopoulou

C.A. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

M. Akthar

P. Albicocco

J. Albrecht

R. Aleksiejunas

F. Alessio

P. Alvarez Cartelle

R. Amalric

S. Amato

J.L. Amey

Y. Amhis

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

C. Arata

F. Archilli

Z. Areg

M. Argenton

S. Arguedas Cuendis

L. Arnone

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

J.A. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J.J. Back

P. Baladron Rodriguez

V. Balagura

A. Balboni

W. Baldini

Z. Baldwin

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I.R. Barbosa

R.J. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

S. Bashir

B. Batsukh

P.B. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I.B. Bediaga

N.A. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

F. Betti

J. Bex

O. Bezshyyko

J. Bhom

M.S. Bieker

N.V. Biesuz

A. Biolchini

M. Birch

F.C.R. Bishop

A. Bitadze

A. Bizzeti

T. Blake

F. Blanc

Observation and investigation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>4430</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> structure in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>π</mi><mo>+</mo></msup></math> decays

The associated production of a photon and a top-antitop quark pair $$ \left(t\overline{t}\gamma \right) $$ is important for measuring the top-quark charge and probing the top-photon interaction, and it requires improved theoretical predictions. We focus on the calculation of two-loop amplitudes for $$ t\overline{t}\gamma $$ production at hadron colliders. The infrared singularities with full top-quark mass dependence are derived from universal anomalous dimensions combined with one-loop massive amplitudes expanded to higher orders in the dimensional regulator $\textit{ϵ}$. The finite remainders are approximated in the high-energy boosted limit using the mass-factorization formula. To validate our approach, we compare approximate one-loop amplitudes up to $$ \mathcal{O}\left({\epsilon}^2\right) $$ , as well as the two-loop infrared poles, against our exact results. The results in this paper serve as an important step toward next-to-next-to-leading order predictions for $$ t\overline{t}\gamma $$ production.

France

Guoxing Wang

China

Li Yang

Two-loop QCD amplitudes for $$ t\overline{t}\gamma $$ production at hadron colliders

We investigate static black hole solutions in three-dimensional <math altimg='si1.svg'><mrow><mo>(</mo><mn>2</mn><mo linebreak='goodbreak'>+</mo><mn>1</mn><mo>)</mo></mrow></math> spacetime within the framework of modified <italic>F</italic>( <italic>Q, T</italic>) gravity, where the gravitational action depends on the non-metricity scalar <italic>Q</italic> and the trace of the energy-momentum tensor <italic>T</italic>. Considering a linear model <math altimg='si11.svg'><mrow><mi>F</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><msub><mi>C</mi><mn>1</mn></msub><mi>Q</mi><mo linebreak='goodbreak'>+</mo><msub><mi>C</mi><mn>2</mn></msub><mi>T</mi></mrow></math>, we derive the modified field equations under a Schwarzschild-like gauge and obtain both perturbative and numerical solutions. The weak-field expansion is shown to be valid in the asymptotic regime | <italic>a</italic>( <italic>r</italic>)|&#8239;&#8810;&#8239;1, while the near-horizon structure is analyzed through full numerical integration of the coupled differential system. The horizon is defined consistently in <math altimg='si12.svg'><mrow><mn>2</mn><mo linebreak='goodbreak'>+</mo><mn>1</mn></mrow></math> dimensions via <math altimg='si4.svg'><mrow><mi>A</mi><mo>(</mo><msub><mi>r</mi><mo>+</mo></msub><mo>)</mo><mo>=</mo><mn>0</mn></mrow></math>, and the Hawking temperature is obtained from surface gravity without invoking four-dimensional Schwarzschild relations. Using the Wald formalism adapted to non-metricity gravity, we derive the entropy and show that it reduces to <math altimg='si13.svg'><mrow><mi>S</mi><mo linebreak='goodbreak'>=</mo><mi>&#960;</mi><msub><mi>C</mi><mn>1</mn></msub><msub><mi>r</mi><mo>+</mo></msub><mo linebreak='goodbreak'>/</mo><mn>2</mn></mrow></math>, recovering the BTZ result in the limit <math altimg='si14.svg'><mrow><msub><mi>C</mi><mn>1</mn></msub><mo linebreak='goodbreak'>=</mo><mn>1</mn></mrow></math>. A general expression for the heat capacity is obtained, demonstrating that its sign depends on the second radial derivative of the metric function. While BTZ-like geometries yield positive heat capacity and thermodynamic stability, the numerical <italic>F</italic>( <italic>Q, T</italic>) solutions exhibit regions where <math altimg='si15.svg'><mrow><msup><mi>A</mi><mrow><mo>&#8243;</mo></mrow></msup><mrow><mo>(</mo><msub><mi>r</mi><mo>+</mo></msub><mo>)</mo></mrow><mo linebreak='goodbreak'>&lt;</mo><mn>0</mn></mrow></math>, leading to negative heat capacity and instability. Our results show that although the leading-order horizon structure coincides with BTZ geometry, the matter non-metricity coupling significantly modifies the radial structure and thermodynamic stability. This demonstrates that <italic>F</italic>( <italic>Q, T</italic>) gravity in three dimensions admits black hole solutions that are geometrically BTZ-like but thermodynamically distinct.

Iran

S. Davood Sadatian

S. Mohamad Reza Hosseini

Black hole solutions in three-dimensional gravity within the framework of the modified <italic>F</italic>( <italic>Q, T</italic>) gravity model

This study presents a novel interpretation of complexity in the formalism of <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> gravity, where <italic>R</italic> specifies the Ricci scalar, <math altimg='si2.svg'><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub></math> is written as matter Lagrangian that describes characteristics of the matter fields, and <math altimg='si3.svg'><mi mathvariant='script'>T</mi></math> represents the trace of energy-momentum tensor. We commence with the contemplation of the inner sector as a cylindrical configuration having anisotropic matter and linked with the exterior region through a hypersurface. We determine the modified field equations associated with <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> gravity and assume the preliminarily established relations between the conformal tensor and the intrinsic curvature. We consider the generally employed mathematical expressions for Tolman mass and C-Energy and evaluate their relationship with the conformal tensor. The structural scalars are calculated from orthogonal splitting of Riemann tensor, out of which <italic>Y<inf>TF</inf></italic> is categorized as complexity factor for the inferred fluid composition. It is important to specify that the complexity factor is eradicated in the framework of uniform matter configuration and also in the scenario when anisotropic terms are canceled with each other. Significant results related to the Weyl scalar, Tolman mass, and the complexity factor are derived in <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> gravity. The vanishing complexity constraint is considered in order to deal with the modified field equations that have extra degrees of freedom and to find particular solutions corresponding to the specific models.

Pakistan

A. Rehman

Azerbaijan

M. Yousaf

Uzbekistan

Bekzod Rahmatov

Javlon Rayimbaev

Munisbek Akhmedov

Complexity evaluation related to the cylindrically symmetric anisotropic matter in <math altimg='si1.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>,</mo><mi mathvariant='script'>T</mi><mo>)</mo></mrow></math> theory

We carry out an Effective Field Theory (EFT) study of the $$pp \rightarrow \bar{t} t Zh$$ process in the final state. This process can uniquely probe the $$\bar{t} t Zh$$ couplings arising from higher dimensional EFT operators and can also provide bounds on $$\bar{t} t Z$$ coupling deviations. We highlight the importance of the proposed proton-proton Future Circular Collider (FCC-$\textit{hh}$) to study this process and then perform a complete collider analysis by examining the relevant background processes. This allows us to determine the FCC-$\textit{hh}$ sensitivity to probe anomalous $$\bar{t} t Zh$$ couplings.

India

Shankha Banerjee

Rick Gupta

Shilpi Jain

Switzerland

Michelangelo Mangano

Germany

Elena Venturini

An EFT study of the $$pp \rightarrow \bar{t} t Z(ll) h(bb)$$ process at the FCC- $$\varvec{hh}$$

In this paper, we study non-supersymmetric $\textit{AdS}$ × $\textit{S}$ vacuua of $\textit{O}$(16) × $\textit{O}$(16) heterotic theory on a string scale $\textit{T}$ background, which are parameterized by a pair of flux integers. Adding the one-loop scalar potential to the effective theory contributes positively to the cosmological constant, but we find that there is no uplift to de Sitter for any values of the fluxes. We study the fluctuations around these vacua and show that all scalar and tensor modes from the six-dimensional effective theory lie above the Breitenlohner-Freedman bound. The moduli coming from the torus compactification will also be above the bound, at least for a large range of fluxes.

United States

Daniel Robbins

Hassaan Saleem

$\textit{O}$(16) $\textit{× O}$(16) heterotic theory on $\textit{AdS}$ 3 $\textit{× S}$ 3 $\textit{× T}$ 4

We derive the explicit formula for fractional BPS lumps (or fractional instantons) in the $\textit{ℂP}$ nonlinear sigma model on a two-dimensional torus under various shift-clock twisted boundary conditions. After regularizing the $\textit{ℂP}$ model by an $\textit{N}$-component Abelian-Higgs model, those twisted boundary conditions introduce nontrivial ’t Hooft fluxes $\textit{p}$/$\textit{N}$ for the U(1) gauge field, and the topological charge becomes fractionalized as $\textit{k}$ + $\textit{p}$/$\textit{N}$ ∈ $\textit{ℤ}$ + $\textit{p}$/$\textit{N}$. The moduli space is globally determined as the $\textit{ℂP}$ -fiber bundle on a 2-torus, which is a Kähler manifold of complex dimension $\textit{Nk}$ + $\textit{p}$ as predicted by the index theorem. We present two different parametrizations of the moduli space: one of them immediately identifies the small-lump singularity appearing in the $\textit{ℂP}$ limit, while the other makes the modular invariance manifest.

Japan

Yui Hayashi

Tatsuhiro Misumi

Muneto Nitta

Keisuke Ohashi

Yuya Tanizaki

Fractional instantons in 2d $\textit{ℂP}$ $\textit{N}$ − 1 model and 4d Yang-Mills theory with ’t Hooft twists

In this work, we investigate exact black string solutions in the context of $\textit{f}$($\textit{R}$, $\textit{T}$) gravity. Adopting the specific form $$f(R,T) = R + 2\chi T$$ , we consider an anisotropic Kiselev fluid as the matter content and obtain static cylindrical solutions, which are then extended to the rotating case through a suitable coordinate transformation. The influence of the quintessence state parameter $$w_q$$ and the matter–geometry coupling constant $$\chi $$ on the geometry is analyzed. We examine the weak, null, and strong energy conditions, identifying the regions in the parameter space where they are satisfied. Furthermore, we apply the Hamilton–Jacobi method to study the tunneling of scalar particles across the event horizon and derive the corresponding Hawking temperature. The thermodynamic stability of the solutions is investigated by computing the heat capacity, and the conditions for phase transitions are discussed. The results provide a characterization of black strings in $\textit{f}$($\textit{R}$, $\textit{T}$) gravity surrounded by quintessence, highlighting the combined effects of anisotropic matter and modified gravity on their physical properties.

Brazil

L. Santos

L. Barbosa

C. Barros

Kiselev black strings in $\textit{f}$($\textit{R}$, $\textit{T}$) gravity

This research paper explores the structure of hypothetical compact stars, known as strange stars, within the framework of a novel modified theory of gravity called $$f(R,\Sigma ,T)$$ gravity. This theory extends General Relativity by making gravity dependent not only on the Ricci curvature scalar $\textit{R}$ but also on a torsion scalar $$\Sigma $$ and the trace of the matter energy–momentum tensor $\textit{T}$. This introduces a richer coupling between geometry and matter. The study presents a highly exotic, multi-layered stellar model composed of five distinct regions, each with a unique equation of state and geometric properties. The model features a dark-energy-like core with powerful repulsive gravity (anti-gravity), surrounded by successive layers of dust, exotic radiation, and a stiff matter crust, all enveloped by a standard Schwarzschild vacuum exterior. A key finding is the prevalence of negative energy densities and pressures in several layers, a hallmark of exotic matter. These configurations, enabled by the $$f(R,\Sigma ,T)$$ framework, lead to repulsive gravitational effects that radically alter the star’s internal equilibrium. The analysis demonstrates how additional geometry-driven forces within this theory can support such exotic structures, potentially preventing gravitational collapse and resulting in a stable, non-singular object. This work demonstrates that $$f(R,\Sigma ,T)$$ gravity allows for new and complex classes of compact objects with stratified, exotic matter distributions, whose properties and observational signatures would differ significantly from those predicted by standard General Relativity.

Egypt

M. Bakry

Saudi Arabia

A. Eid

Tahia Dabash

The impact of $$f(R,\Sigma ,T)$$ gravity on strange star structure