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

Accurate measurements of fundamental cosmological parameters, especially the Hubble constant ( $$H_0$$ ) and present-day matter density ( $$\Omega _\mathrm{{m} 0}$$ ), are crucial for constraining dark energy (DE) evolution. We analyze the sensitivities of cosmological observables ($\textit{H}$($\textit{z}$), $$D_L(z)$$ , $$\text {E}_{\text {G}}$$ ) to $$\Omega _\mathrm{{m} 0}$$ , $$\omega _{0}$$ , and $$\omega _{a}$$ under different parametrizations. Our results show observables are far more sensitive to $$\Omega _\mathrm{{m} 0}$$ than to DE equation of state parameters (e.g., at $$z \sim 0.5$$ , $\textit{H}$($\textit{z}$)’s $$\Omega _\mathrm{{m} 0}$$ sensitivity is $$\sim 0.7$$ vs. $$\omega _{a}$$ ’s $$\sim 0.04$$ ). This hierarchy mandates high-precision $$\Omega _\mathrm{{m} 0}$$ measurements to accurately constrain time-varying DE. We also find DE parameter sensitivity highly depends on parametrization; the standard CPL form shows low sensitivity to $$\omega _{a}$$ , but $$\omega (z) = \omega _{0}+ \omega _{a}\ln (1+z)$$ significantly enhances it. Our analysis of DESI DR1/DR2 data confirms these theoretical limits: standalone DESI data primarily provides only upper limits for $$\omega _{a}$$ , underscoring insufficient constraining power for a definitive time-varying DE detection. While combined datasets offer tighter constraints, interpretation requires caution due to parametrization influence. We further confirm this point using simulated Supernovae MCMC data. In conclusion, improving $$\Omega _\mathrm{{m} 0}$$ precision and adopting optimized parametrizations are imperative for future surveys like DESI to fully probe dark energy’s nature.

South Korea

Seokcheon Lee

Probing time-varying dark energy with DESI: the crucial role of precision matter density ( $$\Omega _\mathrm{{m} 0}$$ ) measurements

Since 2019, the Extreme Energy Events (EEE) Project has installed three muon detection stations at the Svalbard Islands ( $$78.9^{\circ } \hbox {N}$$ latitude), employing scintillator-based detectors. This initiative represents the first systematic effort to monitor cosmic-muons rates at high geomagnetic latitudes beyond the Arctic Circle, with the objective of improving our understanding of cosmic-ray propagation and modulation in polar regions. The present study analyses temporal variations in the muon detection rates over a six-year period (2019–2025), including the study of periodic modulations and underlying trends in the observed rates.

Italy

M. Abbrescia

C. Avanzini

L. Baldini

R. Baldini Ferroli

G. Batignani

M. Battaglieri

E. Bossini

F. Carnesecchi

D. Cavazza

C. Cicalò

L. Cifarelli

F. Coccetti

E. Coccia

A. Corvaglia

A. Caro

D. Gruttola

S. Pasquale

L. Galante

M. Garbini

L. Ghezzer

I. Gnesi

F. Gramegna

Norway

E. Gramstad

S. Grazzi

E. Haland

Switzerland

D. Hatzifotiadou

P. Rocca

R. Liotino

G. Mandaglio

A. Margotti

G. Maron

M. Mazziotta

A. Mulliri

R. Nania

F. Noferini

F. Nozzoli

F. Ould-Saada

F. Palmonari

M. Panareo

M. Panetta

R. Paoletti

C. Pellegrino

L. Perasso

O. Pinazza

C. Pinto

S. Pisano

K. Piscicchia

L. Quaglia

M. Rasà

F. Riggi

G. Righini

C. Ripoli

M. Rizzi

B. Sabiu

G. Sartorelli

E. Scapparone

M. Schioppa

G. Scioli

A. Scribano

M. Selvi

A. Shtimermann

M. Taiuti

A. Trifirò

M. Trimarchi

C. Vistoli

L. Votano

M. Williams

A. Zichichi

R. Zuyeuski

Measurement of the cosmic-ray rate over the period 2019–2025 at very high latitude (78.9°N)

<p>We propose and evaluate a source-equals-detector search for the deexcitation of the long-lived isomer <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> in natural tantalum (Ta), using a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray transition-edge-sensor (TES) array. Two capabilities absent in conventional high-purity germanium (HPGe) searches are exploited: (i) near-unity containment of low-energy secondaries [internal-conversion (IC) electrons and characteristic x-rays] and of the nuclear recoil, enabling a calorimetric, event-by-event measurement of the total deposited energy in the absorber; and (ii) a delayed-coincidence tag using the subsequent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn></mrow></mmultiscripts></mrow></math> electron-capture (EC) decay to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Hf</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn></mrow></mmultiscripts></mrow></math>. We evaluate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mi>σ</mi></math> discovery reach for IC and for dark-matter (DM)-induced deexcitation in two benchmark scenarios: a strongly interacting DM subcomponent and inelastic DM with off diagonal couplings. Using a background model based on intrinsic radioactivity in the Ta absorber and realistic detector performance, we show that arrays with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>N</mi></mrow><mrow><mi>TES</mi></mrow></msub><mo>=</mo><mn>256</mn></mrow></math> and 1,000 pixels can reach the theoretically expected IC half-life within 2.6 yr and 0.66 yr, respectively. For an array with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>TES</mi></msub><mo>=</mo><msup><mn>10</mn><mn>4</mn></msup></math> and a five-year exposure, the projected sensitivity to DM-induced de-excitation surpasses limits inferred from HPGe nonobservations of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> and probes regions of parameter space not covered by current direct-detection experiments.</p>

Japan

A. Gando

K. Ichimura

K. Ishidoshiro

T. Kikuchi

T. Kishimoto

A. Takeuchi

R. Sato

R. Smith

Probing internal conversion and dark-matter-induced deexcitation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi>Ta</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>180</mn><mi mathvariant="normal">m</mi></mrow></mmultiscripts></mrow></math> with a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray TES array

As double heavy quarkonia, charmonium and bottomonium are generally considered to have small relativistic corrections and can be treated using nonrelativistic models. However, this is not always the case. In this paper, we employ the relativistic Bethe-Salpeter (BS) equation method to calculate the electromagnetic (EM) radiative decays of heavy quarkonium where the $\textit{M}$1 transition provides the leading-order contribution. Compared to nonrelativistic method which only computes $\textit{M}$1 transition, our calculations include $\textit{M}$1 + $\textit{E}$2 + $\textit{M}$3 + $\textit{E}$4 transitions, where the higher-order multipoles, $\textit{E}$2, $\textit{M}$3, and $\textit{E}$4, account for relativistic corrections. The study finds that relativistic effects are large in such transitions even for bottomonium. For instance: the relativistic corrections in the decays $\textit{ψ}$($\textit{nS}$) → $\textit{γη}$ ($\textit{mS}$) ($\textit{n}$ ≥ $\textit{m}$) range from 68$\textit{.}$1% to 83$\textit{.}$2%, while those for ϒ($\textit{nS}$) → $\textit{γη}$ ($\textit{mS}$) range between 65$\textit{.}$9% and 75$\textit{.}$2%.

China

Su-Yan Pei

Wei Li

Wen-Yuan Ke

Yi-Yi Rui

Qiang Li

Guo-Li Wang

Large relativistic corrections to nonrelativistic $\textit{M}$1 transitions in heavy quarkonium

We derive decomposition formulas for supercharacters of quantum affine orthosymplectic superalgebras and twisted quantum affine superalgebras into supercharacters of their finite-type quantum sub-superalgebras, by employing Cauchy-type identities for supersymmetric Schur functions. These formulas are obtained via a folding (reduction) procedure applied to the supercharacters of the finite-dimensional general linear Lie superalgebra <math altimg='si5.svg'><mrow><mi mathvariant='fraktur'>gl</mi><mo>(</mo><mi>M</mi><mo>|</mo><mi>N</mi><mo>)</mo></mrow></math>. As a special case, our results provide explicit character formulas for a class of Kirillov-Reshetikhin modules of quantum affine algebras (and their Yangian counterparts), thereby proving a previously proposed conjecture derived from Bethe ansatz analysis.

Zengo Tsuboi

Character formulas for Kirillov-Reshetikhin modules via folding of supercharacters of <math altimg='si5.svg'><mrow><mi mathvariant='fraktur'>gl</mi><mo>(</mo><mi>M</mi><mo>|</mo><mi>N</mi><mo>)</mo></mrow></math>

We apply Bayesian inference to the order-by-order chiral perturbation theory ( <italic>&#967;</italic>PT) expansions for the axial-vector coupling constant <italic>g<inf>A</inf></italic> and the nucleon mass <italic>m<inf>N</inf></italic>, and thereby infer the scales at which <italic>&#967;</italic>PT breaks down for these two observables. Using a pointwise Bayesian analysis, we find that the inferred breakdown scales are notably different for the two observables. For the chiral expansion of <italic>g<inf>A</inf></italic>, we obtain <math altimg='si20.svg'><msubsup><mn>251</mn><mrow><mo>&#8722;</mo><mn>50</mn></mrow><mrow><mo>+</mo><mn>20</mn></mrow></msubsup></math> MeV and <math altimg='si21.svg'><msubsup><mn>211</mn><mrow><mo>&#8722;</mo><mn>30</mn></mrow><mrow><mo>+</mo><mn>20</mn></mrow></msubsup></math> MeV using two distinct sets of low-energy constants, while for the chiral expansion of <italic>m<inf>N</inf></italic> we infer a significantly larger breakdown scale of <math altimg='si22.svg'><msubsup><mn>491</mn><mrow><mo>&#8722;</mo><mn>90</mn></mrow><mrow><mo>+</mo><mn>60</mn></mrow></msubsup></math> MeV.

Sweden

Andreas Ekström

United States

Daniel R. Phillips

Lucas Platter

Matthias R. Schindler

Inferring the breakdown scales of the chiral expansions for <italic>g<inf>A</inf></italic> and <italic>m<inf>N</inf></italic>

In this work, we investigate the relativistic structure of white dwarfs (WDs) within the framework of modified gravity theory <math altimg='si3.svg'><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>)</mo></mrow><mo linebreak='goodbreak'>=</mo><mi>R</mi><mo linebreak='goodbreak'>+</mo><mi>&#945;</mi><mi>T</mi><msub><mi>L</mi><mi>m</mi></msub></mrow></math>, which introduces a non-minimal coupling between matter and curvature. Using a realistic equation of state (EoS) that includes contributions from a relativistic degenerate electron gas and ionic lattice effects, we solve the modified Tolman-Oppenheimer-Volkoff (TOV) equations for two standard choices of the matter Lagrangian density: <math altimg='si9.svg'><mrow><msub><mi>L</mi><mi>m</mi></msub><mo linebreak='goodbreak'>=</mo><mi>p</mi></mrow></math> and <math altimg='si6.svg'><mrow><msub><mi>L</mi><mi>m</mi></msub><mo linebreak='goodbreak'>=</mo><mo>&#8722;</mo><mi>&#961;</mi></mrow></math>. We show that the extra <italic>&#945;TL<inf>m</inf></italic> term significantly alters the mass-radius relation of WDs, especially at high central densities <math altimg='si11.svg'><mrow><mo>(</mo><msub><mi>&#961;</mi><mi>c</mi></msub><mo>&#8819;</mo><msup><mn>10</mn><mn>8</mn></msup><mo linebreak='goodbreak'>&#8722;</mo><msup><mn>10</mn><mn>9</mn></msup><mspace width='0.16em' /><mrow><mi mathvariant='normal'>g</mi></mrow><mo linebreak='goodbreak'>/</mo><mi>c</mi><msup><mi>m</mi><mn>3</mn></msup><mo>)</mo></mrow></math>, allowing for stable super-Chandrasekhar configurations. In particular, depending on the sign and magnitude of the parameter <italic>&#945;</italic>, the maximum mass can increase or decrease, and in some regimes, the usual critical point indicating the transition from stability to instability disappears. Our findings suggest that <italic>f</italic>( <italic>R, T, L<inf>m</inf></italic>) gravity provides a viable framework to explain the existence of massive WDs beyond the classical Chandrasekhar limit. Using Bayesian inference with WD observational data, we further constrain the coupling parameter <italic>&#945;</italic> for the two choices of the Lagrangian density <italic>L<inf>m</inf></italic>.

Brazil

Edson Otoniel

Juan M.Z. Pretel

Clésio E. Mota

César O.V. Flores

Victor B.T. Alves

Germany

Franciele M. da Silva

White dwarf structure in <italic>f</italic>( <italic>R, T, L<inf>m</inf></italic>) gravity: Beyond the Chandrasekhar mass limit

Several possible excesses around $ 95 $ GeV hint at an additional light scalar beyond the Standard Model. We examine the capability of the Circular Electron-Positron Collider (CEPC) to test this hypothesis in the Higgs-strahlung channel $ e^{+}e^{-} \to ZS $ with $ Z \to\mu^{+}\mu^{-} $ and $ S \to\tau^{+}\tau^{-} $ . A full detector simulation shows that the optimal center-of-mass energy for studying the 95 GeV light scalar is 210 GeV. A deep neural network classifier reduces the luminosity required for discovery by half. At $ L = 20\; \mathrm{ab}^{-1} $ , the $ 5\sigma $ sensitivity of the CEPC to the signal strength $ \mu_{\tau\tau}^{ZS} $ reaches 0.016 and 0.020 for $ \sqrt{s} = 210 $ GeV and 240 GeV, respectively. The corresponding thresholds for a 5% precision measurement are $ \mu_{\tau\tau}^{ZS} \gt 0.10 $ and $ \gt 0.12 $ . At $ \sqrt{s}=210 $ GeV (240 GeV), the $ 5\sigma $ coverage of all N2HDM-Flipped samples with $ \chi^2_{h_{95}} \lt 7.82 $ requires $ L=800\ \mathrm{fb}^{-1} $ (1.22 $ \mathrm{ab}^{-1} $ ). These results establish a 210 GeV run, augmented by machine-learning selection, as the most efficient strategy to confirm or refute the 95 GeV excess at future lepton colliders.

Yabo Dong

Manqi Ruan

Kun Wang

Haijun Yang

Jingya Zhu

Testing a 95 GeV Scalar at the CEPC with Machine Learning * This work was supported by the National Natural Science Foundation of China under Grant No. 12275066 and by the startup research funds of Henan University. The work of K. Wang was also supported by the Open Project of the Shanghai Key Laboratory of Particle Physics and Cosmology under Grant No. 22DZ2229013-3. The work of M. Ruan was also supported by the National Key Program for S&T Research and Development under Contract No. 2024YFA1610603. The work of H. Yang was also supported by the National Natural Science Foundation of China under Grant No. W2441004.

<p>The Heavy Photon Search experiment (HPS) is a fixed-target, electron beam experiment designed to search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> mass resonances and displaced decays using a forward acceptance spectrometer. This paper details the search for naturally long-lived “dark” vector mesons (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mi>D</mi></msub></math>) arising from a dark sector of beyond-Standard-Model strongly interacting massive particles, characterized by a QCD-like <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>D</mi></msub></math> symmetry and coupled to the Standard Model photon via a new <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><mi>D</mi></msub></math> gauge interaction mediated by the “heavy photon,” or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>A</mi><mo>′</mo></msup></math>. The results are based on an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>10</mn><mtext> </mtext><mn>608</mn><mtext> </mtext><mtext> </mtext><mrow><msup><mrow><mi>nb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math> collected during the 2016 HPS engineering run. The displaced vertex search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>V</mi></mrow><mrow><mi>D</mi></mrow></msub><mo stretchy="false">→</mo><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> invariant mass range 39–179 MeV showed no statistically significant evidence for signal above the QED background.</p>

P.H. Adrian

N.A. Baltzell

M. Bondí

S. Boyarinov

C. Bravo

S. Bueltmann

P. Butti

V.D. Burkert

D. Calvo

T. Cao

M. Carpinelli

A. Celentano

France

G. Charles

L. Colaneri

W. Cooper

B. Crowe

C. Cuevas

A. D’Angelo

Armenia

N. Dashyan

M. De Napoli

R. De Vita

A. Deur

Canada

M. Diamond

R. Dupre

H. Egiyan

T. Eichlersmith

L. Elouadrhiri

R. Essig

V. Fadeyev

C. Field

A. Filippi

A. Freyberger

S. Gaiser

M. Garçon

N. Gevorgyan

F.X. Girod

N. Graf

M. Graham

K.A. Griffioen

A. Grillo

M. Guidal

R. Herbst

M. Holtrop

J. Jaros

R.P. Johnson

G. Kalicy

M. Khandaker

V. Kubarovsky

E. Leonora

United Kingdom

K. Livingston

L. Marsicano

T. Maruyama

S. McCarty

J. McCormick

B. McKinnon

K. Moffeit

O. Moreno

C. Munoz Camacho

T. Nelson

S. Niccolai

First displaced vertex search for electroproduced dark-sector strongly interacting massive particles by the HPS experiment