We confront the ghost-free non-local <italic>F</italic>( <italic>R</italic>) gravity theories with the latest Atacama Cosmology Telescope (ACT) constraints on the spectral index of the scalar perturbations and the updated constraints of Planck/BICEP on the tensor-to-scalar ratio. After reviewing how the ghost-free non-local version of <italic>F</italic>( <italic>R</italic>) gravity can be obtained, we show that the de Sitter solution can be obtained in this framework. Also, we show that the resulting theory can be cast in terms of an <italic>F</italic>( <italic>R, &#981;</italic>) theory of gravity. We analyze two models of non-local <italic>F</italic>( <italic>R</italic>) gravity, one power-law and the <italic>R</italic> 2 model, and we show that both models can be compatible with the ACT and updated Planck/BICEP constraints.

Japan

Shin’ichi Nojiri

Spain

Sergei Odintsov

Greece

Azerbaijan

V.K. Oikonomou

Ghost-free non-local <italic>F</italic>( <italic>R</italic>) gravity compatible with ACT

We present a novel framework for analyzing four-body semileptonic weak decays, performing the first high-twist analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>D</mi><mi>s</mi></msub><mo stretchy="false">→</mo><msub><mrow><mo stretchy="false">[</mo><mi>π</mi><mi>π</mi><mo stretchy="false">]</mo></mrow><mi mathvariant="normal">S</mi></msub></math> form factors using light cone distribution amplitudes for the isoscalar two-pion state (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mi>π</mi><mi>DAs</mi></mrow></math>). It is motivated by persistent tensions between phenomenological cascade analyses and QCD-based interpretations of the partonic structure of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub></math> meson. Our study reveals that the twist-three <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mi>π</mi></math> DAs incorporate an asymmetry in the partial-wave expansion, a feature absent in single <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub></math> distribution amplitudes, that drives a substantial cancellation between twist-two and twist-three contributions to the form factors. As a result, the predicted decay rate falls significantly below the experimental value. These findings indicate that the isoscalar two-pion system near the charm scale is not primarily a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>q</mi><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover></math> state, reviving the energy-dependent partonic structures of light scalar mesons by highlighting a fundamental limitation of the single-meson light cone distribution amplitude approach in describing such complex systems.

China

Shan Cheng

Ling-yun Dai

Jian-ming Shen

Shu-lei Zhang

Reviving the energy-dependent partonic structure of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> via two-pion distribution amplitudes

We present a non-singular, definition-level formulation of F-theory by replacing the traditional shrinking-fiber limit of M-theory with compactification on a tower-completed circle described using perfectoid geometry and condensed mathematics. This construction provides an intrinsic eleven-dimensional carrier for modular data and admits a canonical tilting and comparison procedure that yields elliptic geometry as an output rather than an auxiliary input. Using this framework, we establish a precise M-theory/Type IIB dictionary in the constant-coupling sector, showing how the physical axio-dilaton is fixed by eleven-dimensional geometric and topological data. The correspondence is tested at the level of the ten-dimensional bosonic effective action, including its topological couplings inherited from eleven dimensions. The tower-completed geometry naturally organizes global sectors in generalized cohomology, with charge data governed by K-theory and exhibiting a canonical prime-power torsion structure. We further show how this framework extends to varying-coupling backgrounds and duality defects, admits a natural adelic completion with prime-independence, and generalizes to higher-rank and U-duality geometries. We also discuss holographic aspects and the anomaly-refined extension of the duality group beyond the bosonic truncation. Together, these results provide a coherent, non-singular foundation for F-theory and its extensions.

Canada

Arshid Shabir

Indonesia

Bobby Eka Gunara

United Kingdom

Belgium

Mir Faizal

A perfectoid duality between M-theory and F-theory

The Galactic Center excess (GCE) of GeV <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math> rays may hint at dark matter (DM), yet its origin remains debated. Motivated by this, we survey weakly interacting massive particle (WIMP) models that can fit the GCE while satisfying relic-density, direct-detection (DD), and indirect-detection (ID) bounds. We group candidates into hadronic (Higgs portals; simplified scalar/vector mediators), leptonic [<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>i</mi></msub><mo>−</mo><msub><mi>L</mi><mi>j</mi></msub></mrow></msub></math>], and mixed [<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><mi>B</mi><mo>−</mo><mi>L</mi></mrow></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math>-portal] classes. Across all cases, present DD and dwarf-spheroidal <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray limits exclude wide regions, leaving mainly narrow resonant funnels with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mrow><mi>DM</mi></mrow></msub><mo>≃</mo><msub><mi>m</mi><mrow><mi>med</mi></mrow></msub><mo>/</mo><mn>2</mn></math> and portal couplings <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≪</mo><mn>1</mn></math>. In hadronic setups, scalar and vector Higgs portals survive only in a thin strip near <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>h</mi></msub><mo>/</mo><mn>2</mn><mo>≃</mo><mn>62.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> with portal couplings <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>, while the Dirac Higgs and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> portals are essentially excluded. The UV-complete vector Higgs portal retains resonant bands whose viable portal strength depends on the mixing angle. Simplified scalars allow small windows for complex-scalar or vector DM; Dirac DM is strongly disfavored, whereas a pseudoscalar with Dirac DM remains viable over a broader parameter range. For a simplified <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Z</mi><mo>′</mo></msup></math> mediator, a pure vector coupling leaves only a marginal region, while pure axial is excluded by DD/ID bounds. In leptonic scenarios, inverse-Compton emission is essential: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>e</mi></msub></math> (and, to a lesser extent, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo>−</mo><mi>L</mi></math>) fits the GCE with near-thermal cross sections, while <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></math> is disfavored. Overall, viable WIMP explanations are constrained to the finely tuned resonant regime, with leptophilic vectors and pseudoscalar portals emerging as the most robust options.

United States

Chuiyang Kong

Italy

Mattia Di Mauro

Comprehensive study of WIMP models explaining the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>F</mi><mi>e</mi><mi>r</mi><mi>m</mi><mi>i</mi></math>-LAT Galactic Center excess

In this paper we study a complete set of scalar and pseudoscalar four-quark operators, with a particular emphasis on their renormalization within a gauge-invariant renormalization scheme (GIRS). We focus on operators that do not mix with lower-dimensional operators by virtue of their transformation properties under the flavor-symmetry group. This class includes all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>F</mi><mo>=</mo><mn>2</mn></math> operators, as well as their partners that transform under the same irreducible representations of the flavor group. These encompass a substantial subset of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>F</mi><mo>=</mo><mn>1</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>F</mi><mo>=</mo><mn>0</mn></math> operators. The present analysis provides a detailed classification of all four-quark operators, exploring their Fierz identities, symmetry properties, and mixing patterns. Different variants of GIRS are explored, including a “democratic” version that treats all mixing operators uniformly. For selected variants, which exhibit smaller mixing effects, we present the conversion matrices from GIRS to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>MS</mi><mo stretchy="true">¯</mo></mover></math> scheme at next-to-leading order.

Cyprus

G. Spanoudes

M. Costa

K. Mitsidi

H. Panagopoulos

Classification of four-quark operators with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>F</mi><mo>≤</mo><mn>2</mn></math> under flavor symmetry and their renormalization in a gauge-invariant scheme

In this paper, we investigate the traversable wormhole solutions in the presence of charge within the framework of <italic>f</italic>( <italic>R, &#981;</italic>) gravity, where <italic>R</italic> represents the Ricci scalar and <italic>&#981;</italic> denotes the scalar potential, respectively. We also consider the Karmarkar condition for the discussion of wormhole geometry. The obtained shape function satisfies all necessary Morris-Thorne criteria for traversability. We derive and graphically examine the physical characteristics, including energy density and pressure components, for a specific linear charge distribution. Our analysis confirms the violation of the null energy condition in the radial direction. The violation of these energy conditions indicates the presence of exotic matter, which is the main candidate for the existence of a wormhole. Under some sensible conditions, the analysis may give an assurance of the existence of wormhole geometries in the <italic>f</italic>( <italic>R, &#981;</italic>) theory of gravity. Furthermore, we investigate the stability of the wormhole through the Tolman-Oppenheimer-Volkov equation, namely the equilibrium condition. By comparing four distinct <italic>f</italic>( <italic>R, &#981;</italic>) models, we demonstrate the robustness of traversable wormhole solutions in this modified gravity setting and identify parameter ranges that minimize energy condition violations. The results affirm that <italic>f</italic>( <italic>R, &#981;</italic>) gravity, augmented by an electromagnetic field, can support stable, traversable wormhole geometries.

Pakistan

Adnan Malik

M. Waqas Aslam

Wenbin Lin

Muhammad Kashif Shafiq

Saudi Arabia

Fatemah Mofarreh

Ramy M. Hafez

Impact of charge on traversable wormhole solutions and modified <italic>f</italic>( <italic>R, &#981;</italic>) gravity

We investigate late-time cosmic acceleration within the framework of $\textit{f}$($\textit{Q}$) gravity supplemented by a phenomenological nonlinear equation of state of the form $$p = A\rho - B\sqrt{\rho }.$$ Adopting a power-law ansatz $$f(Q)=\gamma ,(Q/Q_0)^{n},$$ we derive analytic expressions for the energy density and Hubble function and confront the model with a combined dataset consisting of CC, SNIa, BAO, quasar, and GRB observations covering $$0.106<z<2.33.$$ A Bayesian MCMC analysis constrains the parameter set $${H_0, A, B, c, n}$$ and yields $$H_0 \simeq 71.6^{+1.0}_{-1.9}~\text {km}~\text {s}^{-1}~\text {Mpc}^{-1}$$ for the joint sample, together with a transition redshift $$z_{\textrm{tr}}\approx 0.68.$$ Cosmographic diagnostics indicate a present-day deceleration parameter $$q_0\approx -0.59,$$ with mild deviations of the jerk and snap parameters from their $$\Lambda $$ CDM values at low redshift. Thermodynamic and causal consistency is ensured by the condition $$0\le c_s^2(z)\le 1,$$ while the matter-sector energy conditions remain satisfied up to $$z\sim {\mathcal {O}}(1).$$ A statistical comparison with the concordance model shows that the proposed $$f(Q)+$$ nEoS scenario achieves a goodness of fit comparable to $$\Lambda $$ CDM over the same dataset, with $$\chi ^{2_{\min }^{\textrm{model}}}=255.93$$ versus $$\chi ^{2_{\min }^{\Lambda \textrm{CDM}}}=260.5$$ and $$\chi ^2_\textrm{red}\approx 0.96$$ for both cases. The Akaike Information Criterion yields $$\Delta {\textrm{AIC}}\approx 1.4,$$ indicating statistical equivalence with a mild preference for $$\Lambda $$ CDM due to its smaller parameter space. Therefore, the model provides a viable description of the late-time expansion history, allowing controlled deviations from $$\Lambda $$ CDM that modestly alleviate, though do not resolve, the $$H_0$$ tension. Several other interesting properties of a nEoS are also elucidated upon.

Türkiye

Mehmet Özansoy

India

Bhupendra Shukla

Değer Sofuoğlu

South Africa

Aroonkumar Beesham

Rajnee Tripathi

Cosmic acceleration in $\textit{f}$($\textit{Q}$) gravity: a nonlinear equation of state approach

The decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mn>0</mn></msup></math> is studied using a sample of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>2712.4</mn><mo>±</mo><mn>14.3</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup><mtext> </mtext><mtext> </mtext><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></math> events collected with the BESIII detector. The decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi><mo stretchy="false">(</mo><mn>1405</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>π</mi><mn>0</mn></msup></math> is observed for the first time in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></math> decays via the intermediate state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> and the product branching fraction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><mi>η</mi><mo stretchy="false">(</mo><mn>1405</mn><mo stretchy="false">)</mo><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>η</mi><mo stretchy="false">(</mo><mn>1405</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><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><mo stretchy="false">)</mo></mrow></math> is determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>3.77</mn><mo>±</mo><mn>0.43</mn><mo>±</mo><mn>0.30</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math>, where the first uncertainty is statistical and the second is systematic. The branching fraction of isospin-violating decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><msup><mi>π</mi><mn>0</mn></msup><mo stretchy="false">→</mo><mi>γ</mi><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mn>0</mn></msup></math> is determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>7.36</mn><mo>±</mo><mn>2.25</mn><mo>±</mo><mn>2.36</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup></math> with statistical significance of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.9</mn><mi>σ</mi></math>. Since no <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>c</mi></msub></math> signal is evident in either the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mn>0</mn></msup></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><msup><mi>π</mi><mn>0</mn></msup></math> mass spectrum, upper limits are set to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>η</mi><mi>c</mi></msub><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>η</mi><mi>c</mi></msub><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><msup><mi>π</mi><mn>0</mn></msup><mo stretchy="false">)</mo><mo>&lt;</mo><mn>3.09</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mrow><mi>η</mi></mrow><mrow><mi>c</mi></mrow></msub><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>η</mi></mrow><mrow><mi>c</mi></mrow></msub><mo stretchy="false">→</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">)</mo><mo>×</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><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><mo stretchy="false">)</mo><mo>&lt;</mo><mn>7.97</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>8</mn></mrow></msup></mrow></math> at 90% confidence level, respectively.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

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

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

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

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

J. Cottee-Meldrum

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

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Observation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><mi>η</mi><mo stretchy="false">(</mo><mn>1405</mn><mo stretchy="false">)</mo></math> via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi><mo stretchy="false">(</mo><mn>1405</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><msup><mi>π</mi><mn>0</mn></msup></math>

Fission fragment spectroscopic measurement has been carried out for the system, 232Th( 9Be, <italic>f</italic>) at E <inf><italic>lab</italic></inf> = 46 MeV. The prompt gamma rays decaying from the excited states of the fission fragments were detected using the INGA (Indian National Gamma Array) spectrometer. The dynamical aspects of the fissioning reaction has been investigated by measuring the contributions from the complete as well as incomplete fusion-fission channels. The relative cumulative isotopic yield distribution profiles of the even-even fission fragments have been measured by using the prompt <italic>&#947;</italic>-ray coincidence analysis technique. From the pair wise measured yields of the fission fragments, the contributions of the competing complete ( 9Be + 232Th &#8239;&#8594;&#8239; 241Pu*) and incomplete (n + 232Th &#8239;&#8594;&#8239; 233Th* and 4,5He + 232Th &#8239;&#8594;&#8239; 236,237U*) fusion-fission channels have been extracted, and the respective values are found to be (66 &#8239;&#177;&#8239; 6)% and (34 &#8239;&#177;&#8239; 4)%. The individual contributions from the two accompanying incomplete fusion-fission channels are also independently measured, and both the channels seem to contribute almost in equal proportions. The measured yields are found to be in good agreement with the GEF (GEneral description of Fission) model predicted results obtained by incorporating the measured contributing factors from the competing fissioning channels. The observed findings are also validated by performing the analysis based on the Bayesian inference method.

Krishna Debnath

Aniruddha Dey

P.K. Nayak

A.K. Mondal

R. Shil

A. Kundu

Biswajit Das

K. Mandal

S. Biswas

P. Dey

A. Bairagya

Vishal Malik

A. Sindhu

B. Mukherjee

D.C. Biswas

R. Palit

K. Banerjee

S. Mukhopadhyay

A. Chakraborty

Exploring fission dynamics of 232Th( 9Be, <italic>f</italic>) following prompt <italic>&#947;</italic>-ray spectroscopy

In this study, we investigate the attributes of compact stars within the configuration of <math altimg='si12.svg'><mrow><mi>f</mi><mo>(</mo><mi mathvariant='script'>G</mi><mo>,</mo><mi>&#966;</mi><mo>)</mo></mrow></math> gravity, by incorporating the Gauss-Bonnet term <italic>G</italic> and a scalar field &#966;. By adopting different functional forms of <math altimg='si12.svg'><mrow><mi>f</mi><mo>(</mo><mi mathvariant='script'>G</mi><mo>,</mo><mi>&#966;</mi><mo>)</mo></mrow></math>, we analyze their impact on the equilibrium structure of dense stellar objects. Further, we adopt the Krori-Barua metric potential, defined as <math altimg='si13.svg'><mrow><mi>&#957;</mi><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><mi>B</mi><msup><mi>r</mi><mn>2</mn></msup><mo linebreak='goodbreak'>+</mo><mi>C</mi></mrow></math> and <math altimg='si14.svg'><mrow><mi>&#955;</mi><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><mi>A</mi><msup><mi>r</mi><mn>2</mn></msup><mo>,</mo></mrow></math> here, <italic>A, B</italic> and <italic>C</italic> are constants. To ensure a physically viable compact configuration, we impose matching conditions between the interior spherically symmetric space-time and the Schwarzschild geometry. Moreover, we investigate the attributes of the celestial star models by assuming the <math altimg='si12.svg'><mrow><mi>f</mi><mo>(</mo><mi mathvariant='script'>G</mi><mo>,</mo><mi>&#966;</mi><mo>)</mo></mrow></math> gravity model. We attain the modified field equations and examine key physical characteristics, namely energy density and pressure components, stability conditions, equation of state, and energy constraints. These findings provide new insights into the viability of alternative gravity models in explaining extreme astrophysical environments and offer potential observational signatures to constrain <math altimg='si12.svg'><mrow><mi>f</mi><mo>(</mo><mi mathvariant='script'>G</mi><mo>,</mo><mi>&#966;</mi><mo>)</mo></mrow></math> gravity through future gravitational wave and electromagnetic observations.

Zoya Asghar

Jordan

M. Farasat Shamir

Uzbekistan

Javlon Rayimbaev

Otaboyev Sirajiddin

Fayzullo Shayimov

Exploring compact stars in modified <math altimg='si12.svg'><mrow><mi>f</mi><mo>(</mo><mi mathvariant='script'>G</mi><mo>,</mo><mi>&#966;</mi><mo>)</mo></mrow></math> gravity