The “imaging-by-smashing” technique <cross-ref refid='br0010' id='crf0090'>[1]</cross-ref> has been developed recently in relativistic nuclear collisions. By smashing heavy nuclei at RHIC and the LHC and analysing the anisotropic expansion (flow) of the final state produced particles, unique information on the structure of the collided nuclei can be obtained. Existing efforts primarily focus on the colliding mode of heavy nuclei collisions. In contrast, nuclear structure studies with collisions of light nuclei and the fixed target mode have not been thoroughly explored despite their significant impact and broad interest. In this Letter, we investigate the nuclear structure of 20Ne and 16O in the fixed-target 208Pb&#8211; 20Ne and 208Pb&#8211; 16O collisions at <math altimg='si1.svg'><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><msub><mrow /><mrow><mi mathvariant='normal'>NN</mi></mrow></msub></mrow></msub></mrow></msqrt></math> = 68.5 GeV, using the parton transport model AMPT. The results of two- and four-particle cumulants of anisotropic flow demonstrate a robust signature of nuclear structure effect that persists regardless of the complex dynamic evolution of the created systems. The comparison to the recent hydrodynamic calculations reveals a new possibility of uncovering the origins of collective flow in small systems. This study highlights the significant impact of the light nuclei collisions at the LHCb SMOG (SMOG2) project.

China

Denmark

Zhiyong Lu

Mingrui Zhao

Emil Gorm Dahlbæk Nielsen

Xiaomei Li

You Zhou

Imprint of light nuclei structure in relativistic nuclear collisions

A precise determination of the CKM angle $\textit{γ}$ from $$ {B}_s^0 $$ oscillations in $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays offers a critical test of the Standard Model and probes for new physics. We present a comprehensive study on the prospects of measuring $\textit{γ}$ at a future Tera-$\textit{Z}$ factory, utilizing the baseline detector concept of the Circular Electron Positron Collider (CEPC). A two-dimensional simultaneous fit framework, incorporating flavor tagging, decay time resolution modeling, and acceptance corrections, is developed using full Monte Carlo simulations of $$ {B}_s^0\to {D}_s^{\mp}\left(\to {K}^{\mp }{K}^{\pm }{\pi}^{\mp}\right){K}^{\pm } $$ decays and inclusive background processes. The effective flavor tagging power reaches 23.6%, while the decay time resolution is determined to be 26 fs. Projecting to full statistics of signal events across three dominant $$ {D}_s^{-} $$ decay channels, we estimate a statistical precision of $\textit{σ}$($\textit{γ}$) = 0$\textit{.}$69 , which corresponds to 4.1 Tera-$\textit{Z}$ boson equivalent data. This study has established the feasibility of sub-degree level $\textit{γ}$ measurements at a $\textit{Z}$ factory, highlighting its unique advantages in time-dependent $\textit{CP}$ violation studies through ultra-precise vertexing and background suppression capabilities.

Ji Peng

Xiaolin Wang

Manqi Ruan

Hengne Li

Shanzhen Chen

Prospect for measurement of $\textit{CP}$-violating observables in $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays at a future $\textit{Z}$ factory

Motivated by the work of Cardoso et al. (2022) <cross-ref refid='br0150' id='crf0030'>[15]</cross-ref> on black holes in galaxies, we derive a new black hole solution surrounded by a Dekel-Zhao (DZ) dark matter profile. The derived metric, influenced by DZ profile parameters, exhibits two distinct regimes: for <math altimg='si1.svg'><mi>r</mi><mo>&#8810;</mo><msub><mrow><mi>r</mi></mrow><mrow><mi mathvariant='normal'>c</mi></mrow></msub></math> ( <math altimg='si2.svg'><msub><mrow><mi>r</mi></mrow><mrow><mi mathvariant='normal'>c</mi></mrow></msub></math> is a characteristic radius), exponential corrections dominate, producing significant deviations from the Schwarzschild solution near dense cores, while for <math altimg='si3.svg'><mi>r</mi><mo>&#8811;</mo><msub><mrow><mi>r</mi></mrow><mrow><mi mathvariant='normal'>c</mi></mrow></msub></math>, these corrections vanish, restoring the Schwarzschild metric at large distances. These findings ensure consistency with general relativity in vacuum. The black hole shadow and deflection angle are analyzed, demonstrating that the shadow radius increases with black hole mass ( <math altimg='si4.svg'><msub><mrow><mi>M</mi></mrow><mrow><mi mathvariant='normal'>BH</mi></mrow></msub></math>), while higher central densities ( <math altimg='si5.svg'><msub><mrow><mi>&#961;</mi></mrow><mrow><mi mathvariant='normal'>ch</mi></mrow></msub></math>) result in smaller shadows, reflecting the environmental impact of dense dark matter halos. Photon dynamics reveal how DZ profiles modify critical impact parameters and effective potentials, with gravitational lensing effects highly sensitive to the characteristic radius ( <math altimg='si2.svg'><msub><mrow><mi>r</mi></mrow><mrow><mi mathvariant='normal'>c</mi></mrow></msub></math>). Smaller <math altimg='si2.svg'><msub><mrow><mi>r</mi></mrow><mrow><mi mathvariant='normal'>c</mi></mrow></msub></math> values lead to larger deflection angles due to stronger gravitational effects near compact cores. This work highlights the significance dark matter profiles in shaping black hole observables, providing a theoretical foundation for future observational studies and advancing the understanding of dark matter-black hole interactions in astrophysical and cosmological contexts.

Türkiye

Ali Övgün

Philippines

Reggie C. Pantig

Black hole in the Dekel-Zhao dark matter profile

The CP-violating phase $$\phi _s$$ <math> <msub> <mi>ϕ</mi> <mi>s</mi> </msub> </math> , the $$B_{s}$$ <math> <msub> <mi>B</mi> <mi>s</mi> </msub> </math> decay width ( $$\varGamma _s$$ <math> <msub> <mi>Γ</mi> <mi>s</mi> </msub> </math> ), and the $$B_{s}$$ <math> <msub> <mi>B</mi> <mi>s</mi> </msub> </math> decay width difference ( $$\varDelta \varGamma _s$$ <math> <mrow> <mi>Δ</mi> <msub> <mi>Γ</mi> <mi>s</mi> </msub> </mrow> </math> ) are sensitive probes to new physics and can constrain the heavy quark expansion theory. The potential for the measurement at future Z factories is studied in this manuscript. It is found that operating at Tera-Z mode, the expected precision can reach: $$\sigma (\phi _s) = 4.6~\textrm{mrad}$$ <math> <mrow> <mi>σ</mi> <mo>(</mo> <msub> <mi>ϕ</mi> <mi>s</mi> </msub> <mo>)</mo> <mo>=</mo> <mn>4.6</mn> <mspace width="3.33333pt"></mspace> <mtext>mrad</mtext> </mrow> </math> , $$\sigma (\varDelta \varGamma _s) = 2.4~\mathrm {ns^{-1}}$$ <math> <mrow> <mi>σ</mi> <mrow> <mo>(</mo> <mi>Δ</mi> <msub> <mi>Γ</mi> <mi>s</mi> </msub> <mo>)</mo> </mrow> <mo>=</mo> <mn>2.4</mn> <mspace width="3.33333pt"></mspace> <msup> <mi>ns</mi> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mrow> </math> and $$\sigma (\varGamma _s) = 0.72~\mathrm {ns^{-1}}$$ <math> <mrow> <mi>σ</mi> <mrow> <mo>(</mo> <msub> <mi>Γ</mi> <mi>s</mi> </msub> <mo>)</mo> </mrow> <mo>=</mo> <mn>0.72</mn> <mspace width="3.33333pt"></mspace> <msup> <mi>ns</mi> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mrow> </math> . The precision of $$\phi _s $$ <math> <msub> <mi>ϕ</mi> <mi>s</mi> </msub> </math> is 40% larger than the expected precision with the LHCb experiment at HL-LHC. If operating at 10-Tera-Z mode, the precision of $$\phi _s $$ <math> <msub> <mi>ϕ</mi> <mi>s</mi> </msub> </math> can be measured at 45% of the precision obtained from the LHCb experiment at HL-LHC. However, the measurement of $$\varGamma _s$$ <math> <msub> <mi>Γ</mi> <mi>s</mi> </msub> </math> and $$\varDelta \varGamma _s$$ <math> <mrow> <mi>Δ</mi> <msub> <mi>Γ</mi> <mi>s</mi> </msub> </mrow> </math> cannot benefit from the excellent time resolution and tagging power of the future Z-factories. Only operating at 10-Tera-Z mode can the $$\varGamma _s$$ <math> <msub> <mi>Γ</mi> <mi>s</mi> </msub> </math> and $$\varDelta \varGamma _s$$ <math> <mrow> <mi>Δ</mi> <msub> <mi>Γ</mi> <mi>s</mi> </msub> </mrow> </math> reach an 18% larger precision than the precision expected to be obtained from LHCb at HL-LHC. The control of penguin contamination at the future Z-factories is also discussed.

Prospect for measurement of the CP-violating phase $$\phi _s$$ <math> <msub> <mi>ϕ</mi> <mi>s</mi> </msub> </math> in the $$B_{s}\rightarrow J/\psi \phi $$ <math> <mrow> <msub> <mi>B</mi> <mi>s</mi> </msub> <mo>→</mo> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <mi>ϕ</mi> </mrow> </math> channel at a future Z factory

Hanhua Cui

Yuexin Wang

Hao Liang

Erratum to: Jet charge identification in the <math> <msup> <mi>e</mi> <mo>+</mo> </msup> <msup> <mi>e</mi> <mo>−</mo> </msup> <mo>→</mo> <mi>Z</mi> <mo>→</mo> <mi>q</mi> <mover> <mi>q</mi> <mo>¯</mo> </mover> </math> $$ {e}^{+}{e}^{-}\to Z\to q\overline{q} $$ process at Z pole

A correction to this paper has been published: https://doi.org/10.1007/JHEP05(2024)210

Erratum to: Jet charge identification in the e+e − → Z → <math> <mi>q</mi> <mover> <mi>q</mi> <mo>¯</mo> </mover> </math> $$ \textrm{q}\overline{\textrm{q}} $$ process at Z pole

Accurate jet charge identification is essential for precise electroweak and flavor measurements at the high-energy frontier. We propose a novel method called the Leading Particle Jet Charge method (LPJC) to determine the jet charge based on information of the leading charged particle. Tested on Z → <math> <mi>b</mi> <mover> <mi>b</mi> <mo>¯</mo> </mover> </math> $$ b\overline{b} $$ and Z → <math> <mi>c</mi> <mover> <mi>c</mi> <mo>¯</mo> </mover> </math> $$ c\overline{c} $$ samples at center-of-mass energy of 91.2 GeV, the LPJC achieves an effective tagging power ϵ eff of 20%/9% for c/b jet, respectively. In combination with the Weighted Jet Charge method (WJC), we develop a Heavy Flavor Jet Charge method (HFJC), which achieves an effective tagging power ϵ eff of 39%/20% for c/b jet, respectively. This paper also discusses the dependencies between jet charge identification performance and the fragmentation process of heavy flavor jets, as well as critical detector performances.

Jet charge identification in the e+e− → Z → <math> <mi>q</mi> <mover> <mi>q</mi> <mo>¯</mo> </mover> </math> $$ \textrm{q}\overline{\textrm{q}} $$ process at Z pole

The discovery of the Higgs boson with its mass around 125 GeV by the ATLAS and CMS Collaborations marked the beginning of a new era in high energy physics. The Higgs boson will be the subject of extensive studies of the ongoing LHC program. At the same time, lepton collider based Higgs factories have been proposed as a possible next step beyond the LHC, with its main goal to precisely measure the properties of the Higgs boson and probe potential new physics associated with the Higgs boson. The Circular Electron Positron Collider (CEPC) is one of such proposed Higgs factories. The CEPC is an e+e− circular collider proposed by and to be hosted in China. Located in a tunnel of approximately 100 km in circumference, it will operate at a center-of-mass energy of 240 GeV as the Higgs factory. In this paper, we present the first estimates on the precision of the Higgs boson property measurements achievable at the CEPC and discuss implications of these measurements.
				

United States

Fenfen An

Yu Bai

Chunhui Chen

Xin Chen

Zhenxing Chen

Joao Guimaraes da Costa

Zhenwei Cui

Yaquan Fang

Chengdong Fu

Jun Gao

United Kingdom

Yanyan Gao

Yuanning Gao

Japan

Shaofeng Ge

Germany

Jiayin Gu

Fangyi Guo

Jun Guo

Tao Han

Shuang Han

Hongjian He

Xianke He

Taiwan

Xiaogang He

Jifeng Hu

Shih-Chieh Hsu

Shan Jin

Maoqiang Jing

Susmita Jyotishmati

Kiuchi Ryuta

Chia-Ming Kuo

Peizhu Lai

Boyang Li

Congqiao Li

Gang Li

Haifeng Li

Liang Li

Shu Li

Tong Li

Qiang Li

Zhijun Liang

Libo Liao

Bo Liu

Jianbei Liu

Hong Kong

Tao Liu

Zhen Liu

Xinchou Lou

Lianliang Ma

South Africa

Bruce Mellado

Xin Mo

Serbia

Mila Pandurovic

Jianming Qian

South Korea

Zhuoni Qian

Nikolaos Rompotis

Alex Schuy

Lianyou Shan

Jingyuan Shi

Xin Shi

Shufang Su

Dayong Wang

Jin Wang

Liantao Wang

Yifang Wang

Yuqian Wei

Yue Xu

Haijun Yang

Ying Yang

Weiming Yao

Dan Yu

Kaili Zhang

Zhaoru Zhang

Xianghu Zhao

Ning Zhou

Precision Higgs physics at the CEPC Supported by the National Key Program for S&T Researh and Development (2016YFA0400400); CAS Center for Excellence in Particle Physics; Yifang Wang’s Science Studio of the Ten Thousand Talents Project; the CAS/SAFEA International Partnership Program for Creative Research Teams (H751S018S5); IHEP Innovation Grant (Y4545170Y2); Key Research Program of Frontier Sciences, CAS (XQYZDY-SSW-SLH002); Chinese Academy of Science Special Grant for Large Scientific Project (113111KYSB20170005); the National Natural Science Foundation of China(11675202); the Hundred Talent Programs of Chinese Academy of Science (Y3515540U1); the National 1000 Talents Program of China; Fermi Research Alliance, LLC (DE-AC02-07CH11359); the NSF(PHY1620074) ; by the Maryland Center for Fundamental Physics (MCFP); Tsinghua University Initiative Scientiﬁc Research Program; and the Beijing Municipal Science and Technology Commission project(Z181100004218003)

We explore the discovery potential of Higgs pair production at a 100 TeV collider via full leptonic mode. The same mode can be explored at the LHC when Higgs pair production is enhanced by new physics. We examine two types of fully leptonic final states and propose a partial reconstruction method, which can reconstruct some useful kinematic observables. It is found that the mT2 variable determined by this reconstruction method and the reconstructed visible Higgs mass are crucial to discriminate the signal and background events. It is also noticed that a new variable, denoted as Δm, which is defined as the mass difference of two possible combinations, is very useful as a discriminant. To examine the detector effects, we consider seven detector setups for a 100 TeV collider and investigate the changes in the sensitivity, and we find that lepton isolation and the minimal lepton Pt cut are crucial in order to reduce the integrated luminosity.

Belgium

Xiaoran Zhao

Zhao Li

Qi-Shu Yan

Discovery potential of Higgs boson pair production through final states at a 100 TeV colliderSupported by Natural Science Foundation of China (11175251, 11305179, 11675185, 11475180, 11575005) The work of Q. Li and Q.S. Yan is partially supported by CAS Center for Excellence in Particle Physics (CCEPP), X. Zhao is partially supported by the European Union as part of the FP7 Marie Curie Initial Training Network MCnetITN (PITN-GA-2012-315877).

None Supervisory Editors of Nuclear Physics B

Editorial note on “Lepton-flavor violation and (g−2)μ in the μν SSM” by Hai-Bin Zhang, Tai-Fu Feng, Shu-Min Zhao and Tie-Jun Gao [Nucl. Phys. B 873 (2) (2013) 300–324]