Based on available experimental results on $ \chi _{cJ}(J=0,1,2) $ decays, we investigated the $ \chi_{cJ}\to PP $ , $ VV $ , $ PV $ , and $ PT $ decays using the $\textit{SU}$(3) flavor symmetry/breaking approach, where $\textit{P}$, $\textit{V}$, and $\textit{T}$ denote light pseudoscalar, vector, and tensor mesons, respectively. With the decay amplitude relations determined by $\textit{SU}$(3) flavor symmetry/breaking, we present the branching ratios for all $ \chi_{cJ}\to PP $ and $ \chi_{cJ}\to VV $ modes, including those without experimental data. While theoretical considerations strongly suppress or even forbid most $ \chi_{cJ}\to PV $ and $ PT $ decays, we also provide quantitative predictions constrained by existing experimental data. Our results are expected to be accessible in future experiments at BESIII and the planned Super Tau-Charm Facility.

China

Bo Lan

Qin-Ze Song

Jin-Huan Sheng

Yi Qiao

Ru-Min Wang

Study of χ$_{cJ}$ ($\textit{J}$ = 0,1,2) decays to light meson pairs based on $\textit{SU}$(3) flavor symmetry/breaking analysis * Supported by the National Natural Science Foundation of China (12175088, 12305100, 12365014) and Graduate Innovation Fund Project of Jiangxi Provincial Department of Education (YJS2024091)

Based on a sample of $2.7\times10^{9}$ $\psi(3686)$ events collected by the BESIII detector operating at the BEPCII collider, the decay $\psi(3686)\to\gamma\chi_{cJ}, \chi_{cJ}\to\eta\eta\eta^{\prime}$ is analyzed. The decay modes $\chi_{c1}$ and $\chi_{c2}\to\eta\eta\eta^{\prime}$ are observed for the first time, and their corresponding branching fractions are determined to be ${\cal{B}}(\chi_{c1}\to\eta\eta\eta^{\prime}) = $ $ (1.40\, \pm 0.13\, (\text{stat.}) \pm 0.09\, (\text{sys.})) \times 10^{-4}$ and ${\cal{B}}(\chi_{c2}\to\eta\eta\eta^{\prime}) = (4.18\, \pm 0.84\, (\text{stat.}) \pm 0.48\, (\text{sys.})) \times 10^{-5}$ . An upper limit on the branching fraction of $\chi_{c0}\to\eta\eta\eta^{\prime}$ is set as $2.59 \times 10^{-5}$ at a 90% confidence level (CL). A partial wave analysis (PWA) of the decay $\chi_{c1}\to\eta\eta\eta^{\prime}$ is performed to search for the $1^{-+}$ exotic state $\eta_1(1855)$ . The PWA result indicates that the structure in the $\eta\eta^{\prime}$ mass spectrum is attributed to $f_0(1500)$ , while in the $\eta\eta$ mass spectrum, it is attributed to the $0^{++}$ phase space. The upper limit of ${\cal{B}}(\chi_{c1}\to\eta_{1}(1855)\eta) \cdot {\cal{B}}(\eta_{1}(1855)\to\eta\eta^{\prime}) \lt $ $ 9.79 \times 10^{-5}$ is set based on the PWA at 90% CL.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

O. Bakina

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. 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

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.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z. Chen

Z.J. Chen

Z.K. Chen

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Search for $\textit{η}$ $_{1}$(1855) in $\textit{χ}$ $\textit{cJ}$ → $\textit{ηηη}$′ decays * Supported in part by National Key R&D Program of China (2023YFA1606000, 2023YFA1606704); National Natural Science Foundation of China (NSFC) (11635010, 11935015, 11935016, 11935018, 12025502, 12035009, 12035013, 12061131003, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017, 12361141819); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; CAS (YSBR-101); 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; Agencia Nacional de Investigación y Desarrollo de Chile (ANID), Chile (ANID PIA/APOYO AFB230003); German Research Foundation DFG (FOR5327); Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation (2021.0174, 2021.0299); Ministry of Development of Turkey (DPT2006K-120470); National Research Foundation of Korea ( NRF-2022R1A2C1092335); National Science and Technology fund of Mongolia; National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources Institutional Development, Research and Innovation of Thailand ( B50G670107); Polish National Science Centre (2024/53/B/ST2/00975); Swedish Research Council (2019.04595); U. S. Department of Energy (DE-FG02-05ER41374)

Within the framework of the next-to-minimal supersymmetric (SUSY) extension of the Standard Model (SM) with a local B-L gauge symmetry (N-B-LSSM), we study lepton flavor violating (LFV) $ \tau\rightarrow e M^+ M^- $ decays: $ \tau \rightarrow e \pi^+\pi^- $ , $ \tau \rightarrow e \pi^+K^- $ , and $ \tau \rightarrow e K^+K^- $ . Based on the latest experimental data, the influence of different sensitive parameters on the branching ratios is considered. It can be seen from the numerical analysis that the main sensitive parameters and LFV sources are non-diagonal elements corresponding to the initial and final leptons. This work can provide a basis for discovering the existence of new physics (NP).

Rong-Zhi Sun

Shu-Min Zhao

Shuang Di

Portugal

Xing-Xing Dong

Study of ${\boldsymbol\tau\rightarrow {\boldsymbol e M^+ M^-}}$ decays in N-B-LSSM * Supported by National Natural Science Foundation of China (NNSFC) (12075074), Natural Science Foundation of Hebei Province (A2023201040, A2022201022, A2022201017, A2023201041), Natural Science Foundation of Hebei Education Department (QN2022173), Post-graduate's Innovation Fund Project of Hebei University (HBU2024SS042), the Project of the China Scholarship Council (CSC) (202408130113). X. Dong acknowledges support from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the projects CFTP FCT Unit (UIDB/00777/2020, UIDP/00777/2020)

Vector-like quarks (VLQs) feature in new physics models beyond the standard model (SM) to address certain problems it faces. In this study, we investigate the pair production of TeV-scale vector-like $\textit{B}$ quark (VLQ-$\textit{B}$) at the proposed 3 TeV compact linear collider (CLIC) using a simplified effective lagrangian framework. We consider the decay modes of $ B\rightarrow bZ $ and $ B\rightarrow bh $ , coupled with the hadronic decay of $\textit{Z}$ and $\textit{h}$ bosons. The large mass of VLQ-$\textit{B}$ results in highly boosted $\textit{Z}$ or $\textit{h}$ bosons, which tend to form fat-jets. Using detector simulation of the signal and background events, along with jet clustering employing a large radius $\textit{R}$, we conduct signal-background analyses. Exclusion limits at the 95% confidence level and 5 $ \sigma $ discovery prospects are obtained assuming an integrated luminosity of 5 ab$^{−1}$.

Shuo Yang

Yi-Hang Wang

Peng-Bo Zhao

Ji-Long Ma

Search for heavy vector-like $\textit{B}$ quark via pair production in fully hadronic channels at CLIC * Supported in part by the National Natural Science Foundation of China (12147214, 11905093), Basic Research Project of Liaoning Provincial Department of Education for Universities (LJKMZ20221431), and Teaching Reform Research Project for graduates of Liaoning Normal University

In this manuscript we examine the high energy channeling radiation datasets from the CERN-NA63 experiment using ultrarelativistic synchrotron emission. To incorporate recoil, we examine the standard quasiclassical formalism as well as develop a formalism that includes the Unruh effect by utilizing a hyperbolic recoil acceleration, based on conservation of momentum, in the classical synchrotron trajectory. We also perform an asymptotic radiation timescale analysis that predicts a photon energy threshold, beyond which the Unruh effect dominates. We then compare the classical, quasiclassical, and Unruh synchrotron theories to the data. We find that above threshold, the Unruh effect saturates the spectrum of all datasets.

Morgan H. Lynch

Hyperbolic recoil and the Unruh effect at CERN-NA63

Lepton number violation decay $ \omega \to \pi^+ \pi^+ e^-e^- +c.c. $ is searched for via $ J/\psi \to \omega\eta $ using a data sample of $ (1.0087 \pm 0.0044) \times 10^{10} $ $ J/\psi $ events collected via the BESIII detector at the BEPCII collider. No significant signal is observed, and the upper limit on the branching fraction of $ \omega \to \pi^+ \pi^+ e^-e^- +c.c. $ at the 90% confidence level is determined for the first time to be $ 2.8 \times 10^{-6} $ .

Z.H. Duan

Search for the lepton number violation decay $\textit{ω}$→$\textit{π}$ $^{+}$ $\textit{π}$ $^{+}$ $\textit{e}$ $^{−}$ $\textit{e}$ $^{−}$+$\textit{c}$.$\textit{c}$. * Supported in part by National Key R&D Program of China (2023YFA1606000, 2023YFA1606704); National Natural Science Foundation of China (NSFC) (12035009, 11875170, 11635010, 11935015, 11935016, 11935018, 12025502, 12035013, 12061131003, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017, 12361141819); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; CAS (YSBR-101); 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; Agencia Nacional de Investigación y Desarrollo de Chile (ANID), Chile (ANID PIA/APOYO AFB230003); ERC (758462); German Research Foundation DFG (FOR5327); Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation (2021.0174, 2021.0299); Ministry of Development of Turkey (DPT2006K-120470); National Research Foundation of Korea (NRF-2022R1A2C1092335); National Science and Technology fund of Mongolia; Polish National Science Centre (2024/53/B/ST2/00975); STFC (United Kingdom); Swedish Research Council (2019.04595); U. S. Department of Energy (DE-FG02-05ER41374)

We present the implementation of the NNLO QCD corrections to double Higgs boson production at hadron colliders in G , matched to the parton shower. We include top-quark mass effects and the resummation of large logarithms of the zero-jettiness $$ {\mathcal{T}}_0 $$ , up to NNLL accuracy. This work extends our previous study, which was performed in the $\textit{m}$ → ∞ infinite top-quark mass approximation, providing a more realistic simulation framework for Higgs boson pair production. We validate our approach against NNLO predictions by M and assess the importance of mass effects comparing with our $\textit{m}$ → ∞ previous implementation.

Simone Alioli

Giulia Marinelli

Davide Napoletano

NNLO+PS double Higgs boson production with top-quark mass corrections in GENEVA

For the present work, we have used the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>HYDJET</mi><mo>+</mo><mo>+</mo></mrow></math> model to explore the production of pure multi-strange hadrons in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Pb</mi><mo>+</mo><mi>Pb</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>2.76</mn></mrow></math> TeV and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV collision energies, respectively. We have performed simulations to investigate transverse momentum (<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi>T</mi></msub></math>) spectra and elliptic flow (<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>v</mi><mn>2</mn></msub></math>) for <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>ϕ</mi></math> mesons and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ω</mi></math> baryons, and compared the results both with the ALICE experimental data and available model predictions for selected central classes. Furthermore, we have calculated the nuclear modification factors (<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>R</mi><mrow><mi>A</mi><mi>A</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>R</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>), which provide a perception of jet quenching phenomena. Hence, our findings enable the study of the energy and system dependence of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>ϕ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ω</mi></math> hadrons production over a wide range of ultrarelativistic collision energies. We also present the particle ratios (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi mathvariant="normal">Ω</mi><mo>/</mo><mi>ϕ</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mover><mi mathvariant="normal">Ω</mi><mo>¯</mo></mover><mo>+</mo></msup><mo>/</mo><msup><mi mathvariant="normal">Ω</mi><mo>−</mo></msup></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi mathvariant="normal">Ω</mi><mo>/</mo><mi>π</mi></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>ϕ</mi><mo>/</mo><mi>π</mi></mrow></math>), offering insights into the strangeness enhancement and chemical properties of the medium at both CERN Large Hadron Collider collision energies. Additionally, we also explore the predictions for the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Ω</mi></math> baryon in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Pb</mi><mo>+</mo><mi>Pb</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV, focusing on <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>R</mi><mrow><mi>A</mi><mi>A</mi></mrow></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>R</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>, and particle ratios within the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>HYDJET</mi><mo>+</mo><mo>+</mo></mrow></math> framework, offering insights into future measurements and particle dynamics in high-energy heavy-ion collisions.

India

Gauri Devi

B.K. Singh

Production of multistrange hadrons in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>Pb</mi><mo>+</mo><mi>Pb</mi></mrow></math> collisions at energies available at the CERN Large Hadron Collider using the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>HYDJET</mi><mo>+</mo><mo>+</mo></mrow></math> model

In the present work, O-O collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>7</mn><mspace width="0.16em"></mspace><mi>TeV</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>p</mi></math>-O collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>9.9</mn><mspace width="0.16em"></mspace><mi>TeV</mi></mrow></math> are studied using the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal" mathsize="small">PYTHIA8</mi></math>/Angantyr model for heavy-ion collisions. The theoretically predicted <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>α</mi></math>-cluster structure of oxygen nucleus is implemented in the model to investigate the effect of the initial configuration of the oxygen nucleus on final state observables. The results obtained from the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>α</mi></math>-cluster structure are compared with those obtained from Woods-Saxon nuclear charge density distribution. The Angantyr model simulation showed that the radial distribution of the oxygen nucleus in <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>α</mi></math>-cluster configuration is more compact in comparison to the Woods-Saxon distribution. The results on charged and identified particle pseudorapidity distribution are obtained in the two initial state configurations of the oxygen nucleus. The results demonstrated that the effect of initial geometrical configuration is more distinct in the noncentral collisions in comparison to the central collisions for both O-O and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>p</mi></math>-O collisions.

Deependra Sharma

Arpit Singh

Md. Samsul Islam

Basanta Nandi

Sadhana Dash

Effect of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>α</mi></math> clusters on particle production in O-O and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>p</mi></math>-O collisions at energies available at the CERN Large Hadron Collider

The effect of electron-electron interaction on positron emission in supercritical collisions of highly charged ions is studied within the monopole approximation using the time-dependent density functional theory and time-dependent Hartree–Fock–Slater methods. Positron production probabilities and energy spectra are calculated for U–U, U–Cm, and Cm–Cm collision systems, considering both bare nuclei and highly charged ions with partially filled electron shells. The results indicate that the screening of the nuclear potential by electrons as well as Pauli blocking substantially reduce positron production and suppress the characteristic signatures of spontaneous vacuum decay, previously found in collisions of bare nuclei.

N.K. Dulaev

D.A. Telnov

R.V. Popov

V.M. Shabaev

Y.S. Kozhedub

X. Ma

I.A. Maltsev

A.D. Mironov

I.I. Tupitsyn

Effect of electron–electron interaction on pair production in supercritical collisions of highly charged ions * The calculations within the TDDFT approach were supported by the Russian Science Foundation (22-62-00004, https://rscf.ru/project/22-62-00004/). The calculations performed using the TDHFS method were supported by the Theoretical Physics and Mathematics Advancement Foundation 'BASIS' (23-1-1-54-3). The computations were conducted based on the HybriLIT heterogeneous computing platform (LIT, JINR)