Using data samples collected by the BESIII detector located at the Beijing Electron Positron Collider, the cross sections of the process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">→</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> are measured at 45 center-of-mass energies from 3.808 to 4.951 GeV. An investigation on the energy-dependent cross section is performed, and no significant structure is observed.

China

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

Germany

O. Afedulidis

X.C. Ai

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

I. Balossino

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

J.F. Chang

G.R. Che

G. Chelkov

C. Chen

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

Y.B. Chen

Y.Q. Chen

Z.J. Chen

Z.Y. Chen

South Korea

S.K. Choi

G. Cibinetto

F. Cossio

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

Z.H. Duan

P. Egorov

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

Y.T. Feng

M. Fritsch

C.D. Fu

J.L. Fu

Y.W. Fu

H. Gao

X.B. Gao

Y.N. Gao

Cross section measurement of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">→</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> at center-of-mass energies between 3.808 and 4.951 GeV

The exclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> photoproduction and the exclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Υ</mi></math> photoproduction in proton-proton <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>p</mi><mi>p</mi><mo>)</mo></mrow></math> and proton-lead <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>p</mi><mi>Pb</mi><mo>)</mo></mrow></math> collisions at the energies available at the CERN Large Hadron Collider are investigated using the generalized parton distribution approach. Assuming the Goloskokov-Kroll model, we estimate the corresponding total cross sections and rapidity distributions considering different parametrizations for the unpolarized gluon distribution of the proton. In particular, we compare the linear predictions, associated with Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution, with those derived taking into account the leading nonlinear corrections resulting from gluon recombination. The dependence of our predictions on the choice for the factorization scale is discussed.

Ya-Ping Xie

Brazil

Victor P. Gonçalves

Exclusive heavy-vector-meson photoproduction in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>Pb</mi></mrow></math> collisions within the generalized parton distribution approach: A phenomenological analysis

Topological symmetry operators of holographic large <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>CFT</mi></mrow><mrow><mi>D</mi></mrow></msub></mrow></math>’s are dual to dynamical branes in the gravity dual <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mi>D</mi><mo>+</mo><mn>1</mn></mrow></msub></mrow></math>. We use this correspondence to establish a dictionary between thermal expectation values of symmetry operators in the Euclidean <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>CFT</mi></mrow><mrow><mi>D</mi></mrow></msub></mrow></math> and the evaluation of gravitational saddles in the presence of a dynamical brane. Expectation values of 0-form symmetry operators in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>CFT</mi></mrow><mrow><mi>D</mi></mrow></msub></mrow></math> are then related to branes wrapped on volume minimizing cycles in the bulk, i.e., the Euclidean continuation of a black hole horizon. We illustrate with some representative examples, including gravity in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math>, duality/triality defects in four-dimensional <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">N</mi><mo>=</mo><mn>4</mn></math> super Yang-Mills theory, and the dual of R-symmetry operators probing five-dimensional Bogomol’nyi–Prasad–Sommerfield black holes.

Jonathan J. Heckman

Max Hübner

Chitraang Murdia

On the holographic dual of a symmetry operator at finite temperature

The Atacama Cosmology Telescope (ACT) Collaboration has reported a scalar spectral index <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>n</mi><mi>s</mi></msub><mo>=</mo><mn>0.9743</mn><mo>±</mo><mn>0.0034</mn></math>. This is substantially larger than the classical prediction of nonminimally coupled inflation models such as Higgs Inflation, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>n</mi><mi>s</mi></msub><mo>≈</mo><mn>0.965</mn></math>. Here we revisit the unitarity-conserving nonminimally coupled inflation model proposed by R. N. Lerner and J. McDonald [<a href="http://dx.doi.org/10.1103/PhysRevD.82.103525">Phys. Rev. D 82, 103525 (2010)</a>]. We show that when the inflaton is a complex nonminimally coupled gauge singlet scalar with additional interactions in the Jordan frame to maintain unitarity, the model predicts <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>n</mi><mi>s</mi></msub><mo>=</mo><mn>0.9730</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>r</mi><mo>≈</mo><mn>9</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></math> for scalar self-coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi><mo>=</mo><mn>0.1</mn></math>.

United Kingdom

John McDonald

Unitarity-conserving nonminimally coupled inflation and the ACT spectral index

We develop a unified dynamical systems framework for spatially flat FLRW cosmology in $\textit{f}$($\textit{Q}$) gravity, covering all three connection branches using a single set of Hubble-normalised variables without fixing the function $\textit{f}$($\textit{Q}$) a priori. This model-independent and connection-agnostic approach enables direct comparison across connection choices and uncovers structural features of the cosmological dynamics not visible in connection-specific formulations. While the existing works narrowly focus only on fixed point analysis, in our work we put special efforts to identify the invariant submanifolds, model-independent trajectories and physically viable regions of phase space across connections. For a broad class of viable $\textit{f}$($\textit{Q}$) models, we establish the generic existence of de Sitter attractors and matter-dominated fixed points in the two branches of connection, offering a robust route to late-time acceleration without fine-tuning. We further identify an invariant submanifold that yields $$\Lambda $$ CDM-like background evolution despite underlying dynamics distinct from General Relativity, providing a geometric origin for cosmic acceleration distinguishable only at the perturbation level. We also derive a first integral on this submanifold, allowing analytic reconstruction of the dynamical connection and uncovering hidden conservation laws. Another key feature we found is that while trivial connections exhibit strong parameter dependence, the nontrivial branches often feature parameter-independent behaviours. We also study the variation of the effective gravitational coupling, $$k_{\text {eff}}$$ , across branches and show how this can be constrained using astrophysical observations, which bridges theoretical viability with observational consistency in a novel way. Applying our framework to the illustrative model $$f(Q)=\alpha Q + \beta (-Q)^n$$ , we find late-time acceleration and $$\Lambda $$ CDM-like behaviour without vacuum energy. Finally, we propose a general route for extending dynamical systems analysis to broader classes of $\textit{f}$($\textit{Q}$) models using the $$m_i$$ -hierarchy method. This framework enables closure for models previously inaccessible to standard approaches and offers a diagnostic tool for identifying structurally viable cosmologies within modified gravity theories.

India

Jibitesh Dutta

Wompherdeiki Khyllep

Thailand

South Africa

Saikat Chakraborty

Daniele Gregoris

Khamphee Karwan

A unified dynamical systems framework for cosmology in $\textit{f}$($\textit{Q}$) gravity: generic features across the connection branches

To date, wormholes have not been observed. Dynamic wormholes are difficult to detect due to their transient existence or extremely low spacetime curvature contrast, while static wormholes rely on “exotic matter” that violates the Null Energy Condition and lack direct theoretical support. This study explores the mechanism of dynamic wormhole formation via gravitational collapse of Bose–Einstein Condensate (BEC) dark matter in generalized Vaidya spacetime. Under specific conditions, the gravitational collapse of BEC dark matter interacts with gravitational fields to trigger abrupt changes in spacetime topology. This process depends on special parameters that are more likely to be satisfied in extreme environments. During the collapse, the condensate properties of BEC influence the evolution of spacetime curvature, and its intrinsic oscillatory behavior may facilitate the formation of dynamic wormholes. The research deduces function constraints that satisfy various energy conditions, constructs a dynamic wormhole form adapted to generalized Vaidya spacetime, and derives the Hawking radiation expression and mass function constraints by combining Lorentz-breaking quantum gravity theory. This mechanism confirms the feasibility of dynamic wormhole formation, provides a new perspective for understanding the behavior of dark matter under extreme gravity and the evolution of spacetime topology, and advances wormhole research toward the analysis of dynamic formation processes.

Junjie Wei

Discussion on the feasibility of dynamic wormhole formation based on the gravitational collapse of Bose–Einstein condensed dark matter on generalized Vaidya space-time

We propose a unified model of dark energy and inflation through the Markov–Mukhanov modification of the Einstein–Hilbert action, where the matter sector is coupled to gravity via a scalar coupling function depending only on the energy density of the matter content. We assume that the coupling function encodes the UV corrections to the standard model of cosmology and we determine the form of the coupling that allows for the dark energy component to be dynamical and act as the inflaton field in the early universe. Interestingly we show that our model, in order to account for inflation, prefers a dark energy equation of state with $\textit{w}$ close but not equal to $$-1$$ in agreement with the latest DESI data.

Kazakhstan

Hrishikesh Chakrabarty

Daniele Malafarina

A unified model of dark energy and inflation from the Markov–Mukhanov action

In this paper, we investigate a digitised SU(2) lattice gauge theory in the Hamiltonian formalism. We use partitionings to digitise the gauge degrees of freedom and show how to define a penalty term based on finite element methods to project onto physical states of the system. Moreover, we show for a single plaquette system that in this framework the limit $$g\rightarrow 0$$ can be approached at constant cost.

Timo Jakobs

Marco Garofalo

Tobias Hartung

Cyprus

Karl Jansen

Johann Ostmeyer

Switzerland

Simone Romiti

Carsten Urbach

Dynamics in hamiltonian lattice gauge theory: approaching the continuum limit with partitionings of SU(2)

The Regge–Gribov model of the pomeron and odderon in non-trivial transverse space is studied by the renormalization group technique in the single-loop approximation. The pomeron and odderon are taken to have different bare intercepts and slopes. The behaviour when the intercepts move from below to their critical values compatible with the Froissart limitation is studied. The singularities in the form of non-trivial branch points indicating a phase transition are found in the vicinity of five fixed points reported in a previous publication. Since new phases violate the projectile–target symmetry, the model is found non-physical for the bare intercepts above their critical value.

M. Braun

E. Kuzminskii

M. Vyazovsky

On the reggeon model with the pomeron and odderon: singularities with non-zero masses

We investigate the reconstruction of standard and generalized Rastall gravity inflationary models, using the scalar spectral index and the Rastall parameter expressed as functions of the number of <math altimg='si3.svg'><mrow><mi>e</mi><mo linebreak='goodbreak'>&#8722;</mo></mrow></math>folds <italic>N</italic>. Within a general formalism, we derive the effective potential in terms of the relevant cosmological parameters and the Rastall parameter for these gravity frameworks. As a specific example, we analyze the attractor <math altimg='si4.svg'><mrow><msub><mi>n</mi><mi>s</mi></msub><mrow><mo>(</mo><mi>N</mi><mo>)</mo></mrow><mo linebreak='goodbreak'>&#8722;</mo><mn>1</mn><mo>&#8733;</mo><msup><mi>N</mi><mrow><mo>&#8722;</mo><mn>1</mn></mrow></msup></mrow></math>, first by considering constant values of the Rastall parameter to reconstruct the inflationary stage in standard Rastall gravity, and then by assuming a linear dependence on the number of <math altimg='si3.svg'><mrow><mi>e</mi><mo linebreak='goodbreak'>&#8722;</mo></mrow></math>folds <italic>N</italic> to reconstruct the inflationary model in generalized Rastall gravity. Thus, the reconstruction of the potential <italic>V</italic>( <italic>&#981;</italic>) is obtained for both standard and generalized Rastall gravity inflationary models. In both frameworks, we constrain key parameters of the reconstructed models during inflation using the latest observational data from Planck.

Chile

Ramón Herrera

Carlos Ríos

Reconstructing inflation in a generalized Rastall theory of gravity