Based on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>2.712</mn><mo>±</mo><mn>0.014</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mn>9</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 decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>p</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math>, 1, 2) are observed for the first time with statistical significances exceeding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math>. The measured branching fractions are <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub><mo stretchy="false">→</mo><mi>p</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>7.25</mn><mo>±</mo><mn>0.28</mn><mo>±</mo><mn>0.35</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">→</mo><mi>p</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>1.33</mn><mo>±</mo><mn>0.12</mn><mo>±</mo><mn>0.07</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub><mo stretchy="false">→</mo><mi>p</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.51</mn><mo>±</mo><mn>0.16</mn><mo>±</mo><mn>0.12</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, where the first uncertainties are statistical and the second systematic. In addition, no significant structures are observed in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math> mass spectra.

China

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

Italy

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.B. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

T.T. 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.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z.K. Chen

J.C. Cheng

L.N. Cheng

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

H.L. Dai

J.P. Dai

X.C. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denisenko

M. Destefanis

F. De Mori

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

X.L. Du

Y.Y. Duan

Z.H. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Y.T. Feng

M. Fritsch

Observation and branching fraction measurements of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>p</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup></math>

The inclusive photoproduction of heavy mesons in ultraperipheral <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>P</mi><mi>b</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi><mi>b</mi><mi>P</mi><mi>b</mi></math> collisions at the LHC energies is investigated considering the color-dipole <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-matrix formalism and assuming distinct models for the unintegrated gluon distribution, based on different assumptions for the description of the QCD dynamics. In particular, predictions for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mn>0</mn></msup></math>-meson photoproduction are presented here for the first time. The study of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mn>0</mn></msup></math>-meson photoproduction is revisited by estimating the impact of the treatment of the heavy charm fragmentation on the predictions and extended for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>P</mi><mi>b</mi></math> collisions. Moreover, the contribution associated with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><msup><mi>D</mi><mn>0</mn></msup></math> transition is estimated. Our results indicate that a future experimental analysis of the heavy meson photoproduction will provide important constraints on the description of the hadronic structure at high energies.

Brazil

Victor P. Gonçalves

Luana Santana

Wolfgang Schäfer

Inclusive heavy meson photoproduction in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>P</mi><mi>b</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi><mi>b</mi><mi>P</mi><mi>b</mi></math> collisions

In this work, we have conducted a comprehensive and systematic theoretical investigation of the full cascade decays of charged pseudoscalar mesons, specifically $\textit{D}$ , $\textit{D}$, $\textit{B}$, and $\textit{B}$ , into $\textit{τν}$ , followed by the subsequent decay of the $\textit{τ}$ via its dominant experimentally reconstructible channels: $\textit{τ}$ → $\textit{πν}$ , $\textit{τ}$ → $\textit{ρν}$ , $$ \tau \to e{\overline{\nu}}_e{\nu}_{\tau } $$ , and $$ \tau \to \mu {\overline{\nu}}_{\mu }{\nu}_{\tau } $$ . Our study is framed within the model-independent low-energy effective field theory approach, which incorporates the most general set of four-fermion operators, including those coupling to right-handed neutrinos. We provide precise Standard Model predictions for differential decay rate as a function of the final-state charged particle energy, develop an innovative and robust methodology for extracting the magnitudes of the new physics couplings using energy moments, and identify and characterize fixed points in the normalized energy distributions. The fixed points are invariant under new physics contributions described by the considered effective Hamiltonian.

Quan-Yi Hu

Pseudoscalar meson $$ P\to \tau \left(\to \pi {\nu}_{\tau },\rho {\nu}_{\tau },\ell {\overline{\nu}}_{\ell }{\nu}_{\tau}\right){\overline{\nu}}_{\tau } $$ decays in the Standard Model and beyond

The processes of $ K^-p \to \pi^0 \pi^0 \Sigma^0 $ and $ K^- p \to \pi^0 \Lambda(1405) $ are studied within the effective Lagrangian approach. In addition to the “background” contribution from the $\textit{u}$-channel nucleon pole term, the contribution from the $ \Sigma(1660) $ resonance with spin-parity $ J^P=1/2^+ $ is also considered. For the $ K^-p \to \pi^0 \pi^0 \Sigma^0 $ reaction, we perform a calculation for the total and differential cross sections by considering the contribution from the $ \Sigma(1660) $ intermediate resonance decaying into $ \pi^0 \Lambda(1405) $ with $ \Lambda(1405) $ decaying into $ \pi^0 \Sigma^0 $ . With our model parameters, the available experimental data on both the $ K^-p \to \pi^0 \pi^0 \Sigma^0 $ and $ K^- p \to \pi^0 \Lambda(1405) $ reactions can be fairly well reproduced. It is shown that the contribution from the $ \Sigma(1660) $ resonance is necessary, and that these experimental measurements could be used to determine some properties of the $ \Sigma(1660) $ resonance.

Xing-Yi Ji

Si-Wei Liu

Wen-Tao Lyu

De-Min Li

En Wang

Ju-Jun Xie

Role of Σ(1660) in the $\textit{K}$ $^{−}$ $\textit{p}$ → $\textit{π}$ $^{0}$ $\textit{π}$ $^{0}$Σ$^{0}$ reaction * Supported by the National Key R&D Program of China (2023YFA1606703, 2024YFE0105200), the National Natural Science Foundation of China (12435007, 12475086, 12192263, 12361141819, 1252200936), the Natural Science Foundation of Henan (232300421140, 252300423951) and the Zhengzhou University Young Student Basic Research Projects (PhD students) (ZDBJ202522)

We have performed an updated analysis of the angular distribution of the $ \psi(3686) \to p\bar{p} $ decay by considering transverse beam polarization to investigate potential sources of forward-backward asymmetry and azimuthal modulation beyond the simple $ 1+\alpha\cos^2\theta $ form. We focus on the interference between the $ \psi(3686) $ resonance and two-photon exchange continuum process, as well as on the background from initial-state–final-state radiation (ISR–FSR) interference. A maximum-likelihood fit to the $ \cos\theta $ distribution of $ \psi(3686)\to p\bar{p} $ yields $ \alpha = 1.00 \pm 0.03 $ , which is consistent with previous results. Our model predicts a significant $ \sin(2\phi) $ modulation in the azimuthal angle, indicating the influence of transverse beam polarization. Based on these findings, two-dimensional angular analyses can be conducted in the future to fully disentangle the polarization and interference dynamics in charmonium decays to baryon pairs.

Zhi Gao

Rong-Gang Ping

Minggang Zhao

Update analysis of $ {\psi(3686)\to p\bar{p}}$ * The work is partly supported by the National Natural Science Foundation of China(NSFC) (12575112)

In a recently proposed approach to testing models of inflation by Cosmic Microwave Background (CMB) radiation, the reheating temperature is directly expressed in terms of the CMB observables. Its model-independent bounds translate in a given model into narrow ranges of those observables. In that approach, we analyse the polynomial class of the $\alpha $-attractor inflaton potential models (P-models), in a broad range of polynomials and with the inflaton decays and fragmentation in the reheating period taken into account. The predictions for the CMB observables, the scalar spectral index $n_{\mathrm {s}}$ and tensor-to-scalar ratio $r$, are compared with the Planck and Planck combined with ACT data. Both can be accommodated by that class of the $\alpha $-attractor models. The sensitivity of the results of that comparison to the reheating temperature and to the upper bound on the ratio $r$ is clearly demonstrated. Abstract Published by the Jagiellonian University 2026 authors

M. Marciniak

M. Olechowski

S. Pokorski

Testing $\alpha $-attractor P-model of Inflation by Cosmic Microwave Background Radiation

The reaction mechanism of the quasi-free scattering (QFS) reaction 12C( <italic>p</italic>, 2 <italic>p</italic>) 11B is investigated in inverse and complete kinematics using a 12C beam at 400 MeV/nucleon impinging on a polyethylene (CH <inf>2</inf>) target. A complete set of kinematic observables characterizing the three-body final state is obtained through the exclusive reconstruction of the 11B recoil fragment and the two outgoing protons. For the first time, a systematic Treiman-Yang test is applied to inverse-kinematics ( <italic>p</italic>, 2 <italic>p</italic>) reactions with a heavy-ion beam, taking advantage of the large phase space covered by the experimental setup, particularly in non-coplanar kinematic configuration. This model-independent test confirms the predominance of the QFS reaction mechanism. The characteristic dependence of the Treiman-Yang angle on the azimuthal correlation of the outgoing protons, along with other kinematic signatures, provides further evidence for the single-step proton knockout process.

V. Panin

M. Holl

J.T. Taylor

Y. Aksyutina

Spain

H. Alvarez-Pol

T. Aumann

C.A. Bertulani

K. Boretzky

C. Caesar

M. Chartier

L.V. Chulkov

D. Cortina-Gil

J. Enders

O. Ershova

H. Geissel

R. Gernhäuser

M. Heil

H.T. Johansson

B. Jonson

A. Kelić-Heil

C. Langer

T. Le Bleis

R. Lemmon

T. Nilsson

O. Kiselev

S. Paschalis

M. Petri

R. Plag

R. Reifarth

D. Rossi

H. Scheit

H. Simon

F. Wamers

H. Weick

C. Wimmer

Probing QFS mechanism with the 12C( <italic>p</italic>, 2 <italic>p</italic>) 11B reaction in inverse kinematics

The unsuppressed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in QCD is a problem in the standard model. If we have some mechanism to guarantee real determinants of the quark mass matrices, the vanishing physical vacuum angle <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>θ</mi><mo stretchy="false">¯</mo></mover></math> indicates the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> invariance at the fundamental level. Thus, the small <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>θ</mi><mo stretchy="false">¯</mo></mover></math> is technically natural, since we have an enhanced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> symmetry in the limit of the vanishing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>θ</mi><mo stretchy="false">¯</mo></mover><mo>=</mo><mn>0</mn></math>. In fact, it was proved that the vacuum angle is never renormalized up to the four-loop level once it is fixed at 0 value at some high energy scale. The purpose of this paper is to construct a model that guarantees the real determinants of the quark mass matrices assuming a noninvertible symmetry. In the present model, we have only one <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violating phase and hence all observable phases such as phases in the Cabibbo-Kobayashi-Maskawa matrix, in the neutrino oscillation and in the leptogenesis are related. It should be remarkable that the correct sign of the baryon-number asymmetry in the present Universe is obtained and a narrow region for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violating phase <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi mathvariant="italic">CP</mi></mrow></msub><mo>≃</mo><mn>19</mn><mn>2</mn><mi>°</mi><mi>–</mi><mn>19</mn><mn>7</mn><mi>°</mi></mrow></math> is predicted.

Japan

Tatsuo Kobayashi

Hajime Otsuka

Morimitsu Tanimoto

Tsutomu T. Yanagida

GUT-motivated noninvertible symmetry as a solution to the strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> problem and the neutrino <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-violating phase

<list id='lst0001'><list-item id='lstitem0001'><label>&#8226;</label><para id='p0001'>Tensor interactions are a key component of the nucleon&#8211;nucleon interactions.</para></list-item><list-item id='lstitem0002'><label>&#8226;</label><para id='p0002'>They create strong proton&#8211;neutron correlations and high-momentum components.</para></list-item><list-item id='lstitem0003'><label>&#8226;</label><para id='p0003'>Tensor interactions affect shell evolution and magic numbers far from stability.</para></list-item><list-item id='lstitem0004'><label>&#8226;</label><para id='p0004'>Knockout reactions probe high-momentum nucleons but are difficult for rare isotopes.</para></list-item><list-item id='lstitem0005'><label>&#8226;</label><para id='p0005'>Zero-degree neutron pickup sensitively probes tensor-driven high momentum nucleons.</para></list-item></list>

X. Wang

H.J. Ong

S. Terashima

I. Tanihata

Y.K. Tanaka

N. Aoi

Y. Ayyad

J. Benlliure

F. Farinon

H. Fujioka

Netherlands

India

J. Gellanki

C.L. Guo

E. Haettner

W.L. Hai

Observation of tensor-driven high-momentum neutrons in 16O via ( <italic>p, d</italic>) reactions and zero-degree deuteron momentum spectroscopy