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.

China

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

Poland

M. Marciniak

M. Olechowski

S. Pokorski

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

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

In this study, we explore temperature-dependent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation during big bang nucleosynthesis (BBN) through electron-positron mass asymmetries parametrized by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>b</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mi>T</mi><mo stretchy="false">)</mo><mo>=</mo><mi>α</mi><msup><mi>T</mi><mn>2</mn></msup></math>. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>T</mi><mn>2</mn></msup></math> scaling naturally evades stringent laboratory bounds at zero temperature while allowing for significant <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation at MeV scales in the early Universe [S. Navas et al. (Particle Data Group), <a href="http://dx.doi.org/10.1103/PhysRevD.110.030001">Phys. Rev. D 110, 030001 (2024)</a>]. Using a modified version of the BBN code PRyMordial with dynamically-solved chemical potentials and appropriate finite-mass corrections, we constrain electron-positron mass differences from observed abundances of helium-4, deuterium, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>eff</mi></msub></math>. We find that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>α</mi></math> must be greater than or approximately equal to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mrow><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> for keV-scale mass differences at BBN. All three observables show no simultaneous <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1</mn><mi>σ</mi></math> overlap, though pairwise combinations allow for constrained regions of parameter space. We present two toy models demonstrating how <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>b</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mi>T</mi><mo stretchy="false">)</mo><mo>∝</mo><msup><mi>T</mi><mn>2</mn></msup></math> arises from field-theoretic mechanisms, including temperature-driven phase transitions. These results provide the most stringent constraints on early-Universe <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation in this regime, probing parameter space inaccessible to laboratory experiments.

Spain

Gabriela Barenboim

Anne-Katherine Burns

Temperature-dependent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation: Constraints from big bang nucleosynthesis

We construct singly and doubly spinning non-supersymmetric F1–P black ring solutions in five-dimensional supergravity. These black rings have regular horizons and non-zero temperature. The singly spinning configuration lies in the duality orbit of the black ring constructed by Elvang, Emparan, and Figueras, while the doubly spinning configuration is a charged extension of the black ring constructed by Chen, Hong, and Teo. We analyze the physical properties of these solutions and the various limits they admit. In particular, the doubly spinning solution admits an extremal limit in which the entropy satisfies the relation $\textit{S}$ = 2$\textit{πJ}$ , thereby linking it directly to the angular momentum on the $\textit{S}$ .

India

Pavan Dharanipragada

Gurmeet Punia

Amitabh Virmani

Non-supersymmetric F1-P black rings

In this paper we consider the localization of the gravitino field on a codimension-one thick brane within the framework of $\textit{f}$($\textit{R}$, $\textit{Q}$, $\textit{P}$) gravity. First, setting $$F(\phi ) = \phi $$ , we derive the potential functions for various parameters. Under appropriate coupling parameters, we can find the localized zero mode and some resonance states. Furthermore, we use these resonance states as initial data to investigate the evolution of the gravitino resonances. It can be observed that various parameters on the brane affect the evolution duration. We focus on comparing the localization behavior of the gravitino field on the brane for the cases with $$k=0$$ and $$k\ne 0$$ .

Xiang-Nan Zhou

Miao Wang

Zhi-Chao Duan

Localization of gravitino field on $\textit{f}$($\textit{R}$, $\textit{Q}$, $\textit{P}$) brane

We study Collins azimuthal asymmetries for pion-in-jet production in polarized lepton-proton collisions, extending previous analyses of polarized <italic>pp</italic> scattering to a complementary and theoretically simpler process. We keep adopting a simplified transverse momentum dependent (TMD) approach, with a collinear configuration for the initial state, and employ the transversity and Collins fragmentation functions as extracted from semi-inclusive deep inelastic scattering and <math altimg='si3.svg'><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>&#8722;</mo></msup></mrow></math> annihilation processes. We then compute azimuthal asymmetries for the Electron-Ion Collider (EIC) kinematics, both within a leading order (LO) approach and by including quasireal photon exchange in the Weizs&#228;cker-Williams approximation. Although this contribution is relevant in the whole kinematical range explored, it does not spoil the dominance of quark-initiated channels, leaving only a marginal role to their gluon counterparts. In this respect, Collins asymmetries in lepton-proton processes allow for a much clearer access to the transversity distribution, including its sea-quark component. As we will argue, a comparison with future EIC data could represent a further step in testing the hypothesis of the universality of the Collins function as well as of the TMD factorization for this class of processes.

Italy

Umberto D’Alesio

Carlo Flore

United States

Marco Zaccheddu

Collins asymmetries for pion-in-jet production in polarized ℓ <italic>p</italic> collisions at the EIC

We construct the index saddle for the supersymmetric F1-P black ring. Our construction proceeds by taking a supersymmetric limit of a non-supersymmetric doubly spinning F1-P black ring. We express the resulting saddle as a three-center Bena-Warner solution. The black ring saddle possesses a finite-area event horizon, yet the two-derivative index vanishes. The solution is singular on certain subspaces of the horizon, where higher-derivative corrections are expected to become important. We argue that, once such corrections are taken into account, the solution can yield a finite result. In particular, we present a scaling analysis showing that the index agrees with the microscopic result, up to an overall numerical constant that cannot be fixed by the scaling argument alone. This analysis applies only within a restricted region of parameter space, whose full significance is not yet fully understood.

Index saddle for supersymmetric F1-P black ring

We present the first measurements of the forward and midrapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math>-meson cross sections from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mo>+</mo><mi>p</mi></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>500</mn></math> and 510 GeV, respectively. We also report the midrapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi><mo>/</mo><msup><mi>π</mi><mn>0</mn></msup></math> ratio at 510 GeV. The forward cross section is measured differentially in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math>-meson transverse momentum (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>p</mi><mi>T</mi></msub></math>) from 1.0 to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>6.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></mrow></math> for pseudorapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.0</mn><mo>&lt;</mo><mo stretchy="false">|</mo><mi>η</mi><mo stretchy="false">|</mo><mo>&lt;</mo><mn>3.8</mn></math>. The midrapidity cross section is measured from 3.5 to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>44</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></mrow></math> for pseudorapidity <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>0.35</mn></math>. Both cross sections serve as critical inputs to an updated global analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math>-meson fragmentation functions.

Hungary

N.J. Abdulameer

U. Acharya

A. Adare

C. Aidala

N.N. Ajitanand

Y. Akiba

R. Akimoto

H. Al-Ta’ani

J. Alexander

M. Alfred

D. Anderson

K.R. Andrews

A. Angerami

Russia

S. Antsupov

K. Aoki

N. Apadula

E. Appelt

Y. Aramaki

R. Armendariz

H. Asano

E.C. Aschenauer

E.T. Atomssa

T.C. Awes

B. Azmoun

V. Babintsev

M. Bai

N.S. Bandara

B. Bannier

E. Bannikov

K.N. Barish

B. Bassalleck

A.T. Basye

S. Bathe

V. Baublis

Germany

C. Baumann

A. Bazilevsky

M. Beaumier

S. Beckman

R. Belmont

J. Ben-Benjamin

R. Bennett

A. Berdnikov

Y. Berdnikov

L. Bichon

D. Black

B. Blankenship

D.S. Blau

South Korea

J.S. Bok

V. Borisov

K. Boyle

M.L. Brooks

D. Broxmeyer

J. Bryslawskyj

H. Buesching

V. Bumazhnov

G. Bunce

S. Butsyk

S. Campbell

P. Castera

P. Chaitanya

C.H. Chen

D. Chen

C.Y. Chi

C. Chiu

M. Chiu

I.J. Choi

J.B. Choi

R.K. Choudhury

Sweden

P. Christiansen

T. Chujo

O. Chvala

V. Cianciolo

Israel

Z. Citron

B.A. Cole

France

Z. Conesa del Valle

M. Connors

R. Corliss

M. Csanád

T. Csörgő

L. D’Orazio

S. Dairaku

A. Datta

M.S. Daugherity

G. David

M.K. Dayananda

K. DeBlasio

K. Dehmelt

A. Denisov

A. Deshpande

E.J. Desmond

K.V. Dharmawardane

Brazil

O. Dietzsch

L. Ding

A. Dion

M. Donadelli

V. Doomra

J.H. Do

O. Drapier

A. Drees

Cross sections of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>η</mi></math> mesons in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mo>+</mo><mi>p</mi></math> collisions at forward rapidity at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>500</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and central rapidity at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>510</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>