We investigate the decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> mesons, i.e., <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>d</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup></math>, and their antiparticles, to two light vector mesons (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>V</mi><mn>1</mn></msub><msub><mi>V</mi><mn>2</mn></msub></math>). We use the SU(2) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin symmetry, which relates <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>0</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>1</mn></math> decay amplitudes through the interchange <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo stretchy="false">↔</mo><mi>s</mi></math> and is an approximate symmetry of the Standard Model (SM), to relate the helicity amplitudes of these decays. Treating all the helicity amplitudes for these decays, and, hence, the reduced matrix elements, as free parameters, we find an acceptable solution within the SM, although this is driven by the fact that the number of observables is smaller than what is needed for a meaningful fit. To reduce the number of free parameters, we then use some apparently reasonable and theoretically motivated approximations, like the dominance of factorizable contributions over the nonfactorizable ones and, hence, a distinct hierarchy between the helicity amplitudes. We find that once the assumption of hierarchy is imposed, there is no solution, both in the exact <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin limit as well as when substantial <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin breaking is allowed for. The tension is primarily driven by the longitudinal polarization fractions in almost all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>1</mn></math> decays, which are significantly smaller than the corresponding theoretical predictions based on the SM and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin symmetry. This is particularly true for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mover accent="true"><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo stretchy="true">¯</mo></mover></math>, for which the individual disagreement with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin-based expectation is more than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>7</mn><mi>σ</mi></math>. Within the SM framework, the only effective resolution would be to entirely disregard the hierarchy between the longitudinal and transverse helicity amplitudes in the heavy-quark limit, as dictated by naive factorization, implying that there must be large nonfactorizable contributions to all these decay amplitudes. We also explore whether some new physics in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi></math> sector that does not respect the hierarchy among the helicity amplitudes can reduce the tension for all the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>S</mi><mo>=</mo><mn>1</mn></math> modes. While the answer is partially in the affirmative, we find that, for simplistic new physics scenarios, the tension still exists and the fit remains poor enough, if the hierarchy exists among the SM amplitudes. Some possible scenarios for a complete solution of the puzzle are also suggested.

India

Debajyoti Choudhury

Suman Kumbhakar

Anirban Kundu

Soumitra Nandi

Polarization fractions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>V</mi><mn>1</mn></msub><msub><mi>V</mi><mn>2</mn></msub></math>: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>-spin constraints and new physics signatures

The first measurement of the magnitude of the CKM quark mixing matrix element |$\textit{V}$ | using on-shell $\textit{W}$-boson decays is presented. The measurement is made with $$ t\overline{t} $$ events from $\textit{pp}$ collision data corresponding to an integrated luminosity of 140 fb at a centre-of-mass energy of 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. A value of:

France

G. Aad

Norway

E. Aakvaag

United States

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Italy

United Kingdom

B. Acharya

A. Ackermann

C. Adam Bourdarios

Poland

L. Adamczyk

S. Addepalli

M. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A. Affolder

Y. Afik

Spain

M. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

A. Ahmad

Azerbaijan

F. Ahmadov

S. Ahuja

China

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

Sweden

T. Åkesson

Japan

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

S. Alderweireldt

Z. Alegria

M. Aleksa

I. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

Saudi Arabia

H. Ali

S. Ali

S. Alibocus

South Africa

M. Aliev

G. Alimonti

C. Allaire

B. Allbrooke

D. Allen

J. Allen

Australia

C. Alley

E. Almazan

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

A. Alvarez Fernandez

M. Alves Cardoso

M. Alviggi

M. Aly

Brazil

Y. Amaral Coutinho

C. Amelung

M. Amerl

T. Amezza

B. Amini

K. Amirie

A. Amirkhanov

D. Amperiadou

S. An

C. Anastopoulos

T. Andeen

J. Anders

A. Anderson

A. Andreazza

S. Angelidakis

A. Angerami

A. Anisenkov

A. Annovi

C. Antel

E. Antipov

M. Antonelli

F. Anulli

M. Aoki

T. Aoki

M. Aparo

L. Aperio Bella

M. Apicella

C. Appelt

A. Apyan

M. Arampatzi

S. Arbiol Val

Measurement of the $\textit{|V}$ $\textit{cb}$ $\textit{|}$ element of the CKM matrix in $$ t\overline{t} $$ decays with the ATLAS detector

Ultralong range angular correlations have been recently reported by the ALICE collaboration in pp collisions 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> below <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">d</mi><msub><mi>N</mi><mrow><mi>ch</mi></mrow></msub><mo>/</mo><mi mathvariant="normal">d</mi><mi>η</mi><mo>=</mo><mn>7</mn></math>. The measurements have been performed as a function of the charged-particle multiplicity at midrapidity (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>ch</mi></mrow></msub></math> in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>η</mi><mo stretchy="false">|</mo><mo>&lt;</mo><mn>0.8</mn></math>), which is known to be strongly sensitive to local multiplicity fluctuations. The present work investigates the impact of the event-activity estimator on ultralong range angular correlations. The study is conducted in the framework of pythia8 with the string shoving mechanism since it gives a nonzero elliptic flow coefficient, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mrow><mn>2</mn><mi mathvariant="normal">Δ</mi></mrow></msub></math>. Such collectivelike effects arise from repulsive interactions between overlapping color strings, without invoking hydrodynamic collectivity. The analysis is conducted as a function of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>ch</mi></mrow></msub></math>, the number of parton-parton scatterings (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>mpi</mi></mrow></msub></math>) and flattenicity. Surprisingly, for ultralong range correlations, pp collisions with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>mpi</mi></mrow></msub><mo>=</mo><mn>1</mn></math> (dijets) seem to be the most sensitive to string shoving. The effect diminishes with increasing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>mpi</mi></mrow></msub></math>. While in data, within uncertainties, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mrow><mn>2</mn><mi mathvariant="normal">Δ</mi></mrow></msub></math> exhibits a weak multiplicity dependence; the string shoving mechanism gives a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>V</mi><mrow><mn>2</mn><mi mathvariant="normal">Δ</mi></mrow></msub></math> that decreases with the increase in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>ch</mi></mrow></msub></math>. The present work therefore supports the picture stating that mechanisms such as string shoving might explain the low multiplicity limit, whereas, hydro becomes relevant in high-multiplicity pp collisions. This work also suggests that flattenicity might be more effective than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mrow><mi>ch</mi></mrow></msub></math> to better handle collectivelike effects.

Mexico

Antonio Ortiz

Dushmanta Sahu

Gyula Bencedi

Finite <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>V</mi></mrow><mrow><mn>2</mn><mi mathvariant="normal">Δ</mi></mrow></msub></mrow></math> puzzle in low-multiplicity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions from ultralong-range azimuthal correlations in the string-shoving model

We present an investigation of the structural properties of heavy-light ( $$D, D_s, B, B_s$$ ) and heavy-heavy ( $$B_c$$ ) mesons by incorporating the $\textit{V}$-scheme strong coupling constant $$\alpha _V$$ up to the third-loop order ( $$N^3$$ LO). The inclusion of three-loop radiative corrections is critical to achieving perturbative convergence and effectively canceling renormalon-induced instabilities. A central feature of this work is the rigorous calibration of the string tension $\textit{b}$ using the universal scaling ratio $$R_{n_f} = \Lambda _{\overline{\text {MS}}}^{(n_f)}/\sqrt{b}$$ , matched to the non-perturbative Sommer scale $$r_0$$ from FLAG 2024 averages. By integrating these flavor-dependent $$N^3$$ LO refinements ( $$b \approx 0.1951 \pm 0.0369$$ GeV $$^2$$ ) into a variational Cornell potential framework, we demonstrate a systematic“stiffening”of the internal structure and a physical spatial contraction across successive loop orders. Our $$N^3$$ LO results for root-mean-square (RMS) matter radii and charge radii exhibit remarkable agreement with established benchmarks: specifically, the $$B_c$$ charge radius (0.191 fm) and matter radius (0.2967 fm) align closely with light-front predictions and relativistic quark model studies. Evaluation of the Isgur–Wise function reveals that while higher-order corrections primarily reshape the light-quark spectator cloud, the heavy core localization remains dominated by the constituent mass scale.

Rishan Choudhury

Pritom Nath

Jugal Lahkar

Variationally improved structure of heavy-light mesons at $$N^3$$ LO: stiffening effects and universal form factors in the $\textit{V}$-scheme

We present BSkG5, the latest entry in the Brussels-Skyrme-on-a-Grid (BSkG) series and the first large-scale nuclear structure model based on next-to-next-to-leading order (N2LO) Skyrme energy density functional (EDF). By extending the traditional Skyrme EDF ansatz with central terms containing up to four gradients, we are able to combine an excellent global description of nuclear ground state properties with a stiff equation of state for pure neutron matter that is consistent with astronomical observations of neutron stars. More precisely, the new model matches the accuracy of earlier BSkG models but with two parameters less: we achieve root-mean-square deviations of 0.649 MeV for 2457 atomic masses, 0.0267 fm for 810 charge radii, and 0.43 MeV for 45 primary fission barriers of actinide nuclei. We demonstrate that the complexities of N2LO EDFs are not insurmountable, even for demanding many-body calculations.

Belgium

G. Grams

W. Ryssens

A. Sánchez-Fernández

N.N. Shchechilin

L. González-Miret Zaragoza

P. Demol

N. Chamel

S. Goriely

M. Bender

Skyrme-Hartree-Fock-Bogoliubov mass models on a 3D mesh: V. The N2LO extension of the Skyrme EDF

We study correlation numbers in Virasoro minimal string [ ]. Using analytic properties of correlation functions in spacelike and timelike Liouville theories, we verify exact expressions for correlation numbers for the four punctured sphere and the once punctured torus conjectured in [ (2024) 057 ].

Russia

Dmitry Khromov

Alexey Litvinov

On correlation numbers $\textit{V}$ 0$\textit{,}$4 and $\textit{V}$ 1$\textit{,}$1 in Virasoro minimal string theory

Within the framework of nonrelativistic QCD (NRQCD) factorization, and based on the Collins-Soper operator definition of fragmentation functions, we present a systematic calculation of the fragmentation functions for a heavy quark fragmenting into color-singlet $\textit{P}$-wave quarkonium states. After reproducing and confirming the known leading-order results, we further compute the relativistic corrections up to order $$ \mathcal{O}\left({v}^2\right) $$ . Our analysis applies both to quarkonium systems composed of heavy quarks with the same flavor and to $\textit{B}$ -type mesons formed by heavy quarks of different flavors. Numerical results show that, for all color-singlet $\textit{P}$-wave channels, the $$ \mathcal{O}\left({v}^2\right) $$ relativistic corrections give sizable negative contributions over most of the momentum-fraction $\textit{z}$ region. We further compute inclusive cross sections for $\textit{P}$-wave quarkonium plus charmed hadrons in $\textit{e}$ $\textit{e}$ annihilation via the single photon process up to $$ \mathcal{O}\left({v}^2\right) $$ by applying our obtained fragmentation functions, and the resulting predictions are consistent with the full fixed-order results in the high-energy region.

Sai Cui

Sheng-Juan Jiang

Guang-Zhi Xu

Kui-Yong Liu

Order-$\textit{v}$ 2 relativistic corrections to heavy-quark fragmentation into $\textit{P}$-wave quarkonium states

The Giant Dipole Resonance (GDR) in 51V has been a long-term conflicting interpretation, with existing photoneutron cross section data suggesting either a single peak or a pronounced splitting, leading to opposite conclusions on nuclear deformation. A new measurement of the 51V( <italic>&#947;</italic>,1n) cross section, performed at the Shanghai Laser Electron Gamma Source (SLEGS) facility, employs a refined monochromatic cross section extraction method. By integrating Polynomial Regression and Support Vector Regression (SVR) for robust interpolation and extrapolation, the new extracted monoenergetic cross sections exhibit a single, broad peak with no evidence of GDR splitting. Re-analysis of the reported splitting shows that any deformation extracted from such a structure would be relatively weaker than those of neighboring nuclei, providing a support for a spherical or near-spherical shape of 51V. Furthermore, we found that deliberately overfitting the data using an SVR model reproduces multi-peak structures similar to those reported in historical datasets, implying that the previously claimed splitting might originated from analysis artifacts rather than physical phenomena.

Zi-Rui Hao

Gong-Tao Fan

Chen Chen

Qian-Kun Sun

Hong-Wei Wang

Yi-Fei Niu

Hang-Hua Xu

Long-Xiang Liu

Yue Zhang

Yu-Xuan Yang

Kai-Jie Chen

Zhi-Cai Li

Pu Jiao

Meng-Die Zhou

Shan Ye

Zhen-Wei Wang

Xiang-Fei Wang

Meng-Ke Xu

Yu-Long Shen

Chang Yang

Jia-Wen Ding

New measurement of 51V( <italic>&#947;</italic>,1n) cross section through the refined monochromatic cross section extraction method

We consider the V-A Fermi interaction and apply an earlier developed method for summing up the leading asymptotics for scattering amplitudes in non-renormalizable theories. We consider the amplitude of fermion-antifermion scattering and derive the corresponding RG equation that sums the leading logarithmic contributions just like in renormalizable models. Numerical solution of this equation in the asymptotic regime <italic>s</italic>&#8239;&#8764;&#8239; <italic>t</italic>&#8239;&#8764;&#8239; <italic>u</italic>&#8239;&#8764;&#8239; <italic>E</italic> 2&#8239;&#8594;&#8239;&#8734; leads to amplitude logarithmically decreasing with energy, thus restoring the unitarity violated at the tree level.

Arthur Borlakov

Dmitry Kazakov

Asymptotic freedom of V-A Fermi interaction

In light of ongoing issues with the first-row unitarity test of the Cabibbo-Kobayashi-Maskawa matrix, we showcase a global fit to measurements of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">→</mo><mo>ℓ</mo><mi>ν</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">→</mo><mi>π</mi><mo>ℓ</mo><mi>ν</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo stretchy="false">→</mo><mi>K</mi><mi>ν</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo stretchy="false">→</mo><mi>K</mi><mi>π</mi><mi>ν</mi></math> decays for the first time. Fitting the semileptonic and three-body <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> decay data simultaneously becomes computationally feasible because we employ a simple form factor parametrization for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mi>π</mi></math> form factor that manifestly connects the semileptonic and pair-production regions. We find good agreement with the data and use our analyses to infer <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>u</mi><mi>s</mi></mrow></msub><mo stretchy="false">|</mo></math> and the parameters for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mi>π</mi></math> form factors. Our result for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>u</mi><mi>s</mi></mrow></msub><mo stretchy="false">|</mo></math> sits close to the results extracted from exclusive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mrow><mo>ℓ</mo><mn>2</mn></mrow></msub></math> and somewhat above the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mrow><mo>ℓ</mo><mn>3</mn></mrow></msub></math> decay and inclusive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> decay result. Moreover, our results for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mo stretchy="false">→</mo><mi>π</mi></math> vector form factor at zero momentum transfer are compatible with lattice QCD determinations, despite not using lattice QCD inputs for this quantity in our fit of the hadronic matrix elements. We are further able to determine some of the pole parameters of the individual scalar and vector <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mi>π</mi></math> resonances with masses below the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> mass. We caution that our results account only for short-distance electromagnetic corrections but not long-distance contributions; this is due to the lack of a consistent description of long-distance corrections to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mi>π</mi></math> matrix elements both above and below threshold for an arbitrary model of the form factors.

Matthew Kirk

Danny van Dyk

Global determination of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">|</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>u</mi><mi>s</mi></mrow></msub><mo stretchy="false">|</mo></mrow></math>