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Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

A detailed theoretical derivation of the cross sections of e+e? → e+e? and e+e? → ?+?? around the J/ψ resonance is reported. The resonance and interference parts of the cross sections, related to J/ψ resonance parameters, are calculated. Higher-order corrections for vacuum polarization and initial-state radiation are consid-ered. An arbitrary upper limit of radiative correction integration is involved. Full and simpli?ed versions of analytic formulae are given with precision at the level of 0.1% and 0.2%, respectively. Moreover, the results obtained in the paper can be applied to the case of the ψ(3686) resonance. |

Influence of the electroplating pretreatment on corrosion mechanism of NdFeB magnets

Zhou, QY [Zhou Qiaoying][ 1 ]; Li, G [Li Gang][ 1 ]; Liu, Z [Liu Zhuang][ 1 ]; Guo, S [Guo Shuai][ 1 ]; Yan, A [Yan Aru][ 1 ]; Lee, D [Lee Don][ 1 ]; Li, JZ [Li Jianzhong][ 2 ]

The electroplating pretreatment of NdFeB magnets was simulated in this study, and the effect of the pickling process on element, matrix morphology and texture was discussed. The results showed that in the ordinary circumstance the acid solution concentrat |

Determination of ψ(2S) Total Number by Inclusive Hadronic Decay

MO Xiao-Hu; ZHU Yong-Sheng; YUAN Chang-Zheng; FU Cheng-Dong; Li GangSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

On the basis of the study of inclusive hadronic events, two methods are adopted to determine the number of produced ψ(2S) events collected by BES in 2001-2002 run, which is 14:0 ? 106 with the uncertainty of 4%. |

Interference effects on Higgs mass measurement in $e^+e^-\to H(\gamma\gamma) Z$ at CEPC

Xu Guang-Zhi; Li Gang; Li Yi-Jie; Liu Kui-Yong; Zhang Yu-JieSubjects: Physics >> Nuclear Physics

A high luminosity Circular Electron Positron Collider (CEPC) as a Higgs Factory will be helpful to the precision measurement of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in the associated Z boson production at the future?e+e??colliders at energy?246GeV. The mass shifts go up from about?20MeV?to?50MeV?for the experimental mass resolution ranging from?0.8GeV?to?2GeV. |

Subjects: Physics >> Nuclear Physics

The Circular Electron Positron Collider (CEPC) is a future Higgs factory proposed by the Chinese high energy physics community. Using Monte Carlo samples of 5 ab?1 at 250 GeV center-of-mass energy, the benchmark luminosity of CEPC Higgs runs, model independent (MI) analyses on Higgsstrahlung (ZH) cross section σZH and Higgs mass mH are performed with ZH events where the Z boson decays into a pair of muons. The relative precision of σZH could reach 0.92\% and the mH could be measured to an accuracy of 6.5 MeV. Using information from Higgs decay final states, the backgrounds could be further reduced, leading to a mass precision of 5.4 MeV. The impacts of tracker size are investigated and parameterized for these measurements. Using similar analysis technology, we analyzed the capability of CEPC in measuring the Higgs invisible decay. Using ZH (Z→μ+μ?) events at 5 ab?1, the upper limit of invisible decay cross section beyond the standard model (SM) σBSMZH,H→inv can be determined to be 2.0 fb at 95\% confidence level. |

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