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)

We study the dissociative associated production of a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> meson and a dimuon via double parton scattering (DPS) in nucleus-proton ultraperipheral collisions. This new channel, characterized by a rapidity gap, is sensitive to the photon and gluon distributions of the proton. We derive a DPS pocket formula for this process, together with a corresponding expression for the effective cross section. Furthermore, we demonstrate the kinematic dependence of the effective cross section and present predictions for the differential DPS cross section at LHC and FCC energies.

Brazil

Bruna O. Stahlhöfer

Edgar Huayra

Emmanuel G. de Oliveira

Dissociative associated <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">J</mi><mo>/</mo><mi>ψ</mi></math> and dimuon production in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi><mi>p</mi></math> ultraperipheral collisions via double parton scattering

The observation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in the difference of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> asymmetries between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> has raised a debate whether the observed asymmetries can be regarded as a signal of physics beyond the standard model (SM). In this paper we obtain all the topological amplitudes and isospin amplitudes directly from measured observables for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi></math>. These results unambiguously imply a very large penguin contribution, having a central value 4.74 times the magnitude of the amplitude for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mn>0</mn></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math>. This fitted central value differs from a reasonable SM estimate of 10% with a significance greater than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.3</mn><mi>σ</mi></math>. In contrast to previous studies, we present model-independent arguments based only on unitarity of rescattering amplitudes to show that large penguins cannot arise from rescattering alone and likely indicate physics beyond the SM. In a model-independent approach we show how a very small contribution from physics beyond the SM with a large weak phase alleviates the problem.

United States

India

Rahul Sinha

Thomas E. Browder

N.G. Deshpande

Poland

Dibyakrupa Sahoo

Nita Sinha

Implications of the evidence for direct <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> decays

This work investigates the possibility of accessing the initial geometric shape of the proton in proton-proton and proton-nucleus collisions at the LHC. In particular, we look for manifestations of the configuration in which the proton is made of three quarks linked by a Y-shape gluon string, called baryon junction. This initial state spatial configuration has been used in the past to describe data on baryon rapidity distributions, diffractive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> production and multiplicity distributions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions. In spite of its success in explaining the data, the evidence of the baryon junction still needs confirmation. Further studies will be undertaken at the electron-ion collider. In this work we study multiplicity distributions measured in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> and pPb collisions. Different initial state geometries are used as input in a Monte Carlo event generator which implements the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>T</mi></msub></math>-factorization formalism of the color glass condensate with Kharzeev-Levin-Nardi unintegrated gluon distributions. The results show that the data on multiplicity distributions are good enough to discriminate between different initial state geometries. Moreover, they indicate that it is crucial to take into account the intrinsic fluctuations of the saturation scale.

R. Terra

A.V. Giannini

F.S. Navarra

Initial-state geometry and multiplicity distributions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>p</mi><mi>Pb</mi></mrow></math> collisions

The angular distributions of Drell–Yan lepton pairs provide sensitive probes of the underlying dynamics of quantum chromodynamics (QCD) effects in vector-boson production. This paper presents for the first time the measurement of the full set of angular coefficients together with the differential cross-section as a function of the transverse momentum of the $\textit{W}$ boson, in the full phase space of the decay leptons. The measurements are performed separately for the $$W^-$$ and $$W^+$$ channels. The analysis uses proton–proton collision data recorded by the ATLAS experiment at the Large Hadron Collider in 2017 and 2018, during special low-luminosity runs with a reduced number of interactions per bunch crossings (pile-up). The data correspond to an integrated luminosity of 338 pb $$^{-1}$$ at a centre-of-mass energy of $$\sqrt{s} = 13$$ TeV. The low pile-up environment provides excellent experimental conditions for high-precision measurements of $\textit{W}$-boson production. All results agree with theoretical predictions incorporating finite-order QCD corrections up to order $$\alpha _S^2$$ .

France

G. Aad

Norway

E. Aakvaag

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

Italy

United Kingdom

B. Acharya

A. Ackermann

C. Bourdarios

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

Azerbaijan

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Tamlihat

B. Aitbenchikh

M. Akbiyik

Sweden

T. Åkesson

A. Akimov

Japan

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

G. Albouy

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

W. Alkakhi

C. Allaire

B. Allbrooke

D. Allen

J. Allen

P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

Z. Alsolami

A. Fernandez

M. Cardoso

M. Alviggi

M. Aly

Y. Coutinho

A. Ambler

C. Amelung

M. Amerl

C. Ames

T. Amezza

D. Amidei

B. Amini

K. Amirie

A. Amirkhanov

Portugal

S. Santos

K. Amos

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

Measurement of the $\textit{W}$-boson angular coefficients and transverse momentum in $$p\!p$$ collisions at $$\sqrt{s}=13$$ TeV with the ATLAS detector

A novel machine-learning-based flavor-tagging algorithm combining same-side and opposite-side tagging is used to obtain the equivalent of 27 500 tagged <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><mi>J</mi><mo stretchy="false">/</mo><mi>ψ</mi><mi>ϕ</mi><mo stretchy="false">(</mo><mn>1020</mn><mo stretchy="false">)</mo></math> decays from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><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>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, collected by the CMS experiment and corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>96.5</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. A time- and flavor-dependent angular analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math> final state, consistent with a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mi>ϕ</mi><mo stretchy="false">(</mo><mn>1020</mn><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math> decay, is used to measure parameters of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo>−</mo><msubsup><mover accent="true"><mi>B</mi><mo accent="true" stretchy="false">¯</mo></mover><mi>s</mi><mn>0</mn></msubsup></math> system. The weak phase is measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>ϕ</mi></mrow><mrow><mi mathvariant="normal">s</mi></mrow></msub><mo>=</mo><mrow><mo>−</mo><mn>73</mn></mrow><mo>±</mo><mn>22</mn><mrow><mo stretchy="false">(</mo><mi>stat</mi><mo stretchy="false">)</mo></mrow><mo>±</mo><mn>10</mn><mrow><mo stretchy="false">(</mo><mi>syst</mi><mo stretchy="false">)</mo></mrow><mtext> </mtext><mtext> </mtext><mi>mrad</mi></mrow></math>, which, combined with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>8</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math> CMS result, gives <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>ϕ</mi></mrow><mrow><mi mathvariant="normal">s</mi></mrow></msub><mo>=</mo><mrow><mo>−</mo><mn>75</mn></mrow><mo>±</mo><mn>23</mn><mtext> </mtext><mtext> </mtext><mi>mrad</mi></mrow></math>. This value differs from zero by 3.2 standard deviations, providing the first evidence for mixing-induced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><mi>J</mi><mo stretchy="false">/</mo><mi>ψ</mi><mi>ϕ</mi><mo stretchy="false">(</mo><mn>1020</mn><mo stretchy="false">)</mo></math> decays. All measured physics parameters are found to agree with standard model predictions where available.

Armenia

A. Hayrapetyan

A. Tumasyan

Austria

W. Adam

J.W. Andrejkovic

L. Benato

T. Bergauer

S. Chatterjee

K. Damanakis

M. Dragicevic

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

T. Van Laer

P. Van Mechelen

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

S. Lowette

I. Makarenko

D. Müller

S. Tavernier

M. Tytgat

G.P. Van Onsem

S. Van Putte

D. Vannerom

B. Bilin

B. Clerbaux

First Evidence for Mixing-Induced <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> Violation in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>s</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>ϕ</mi><mo stretchy="false">(</mo><mn>1020</mn><mo stretchy="false">)</mo></math> Decays in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> Collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math>