The spontaneous conversion of muonium to antimuonium is an interesting charged lepton flavor violation phenomenon that offers a sensitive probe for potential new physics and serves as a tool to constrain the parameter...The spontaneous conversion of muonium to antimuonium is an interesting charged lepton flavor violation phenomenon that offers a sensitive probe for potential new physics and serves as a tool to constrain the parameter space beyond the Standard Model.The Muonium-to-Antimuonium Conversion Experiment(MACE)was designed to utilize a high-intensity muon beam,a Michel electron magnetic spectrometer,a positron transport system,and a positron detection system to either discover or constrain this rare process with a conversion probability of O(10^(-13)).This article presents an overview of the theoretical framework and a detailed description of the experimental design for muonium-to-antimuonium conversion.展开更多
Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudin...Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudinal to transverse cross section of the J/ψandρ^(0)productions are calculated with the analytical solution of the Balitsky-Kovchegov(BK)equation.In addition,we consider the influences of two meson wave function models on the results.Our predictions,which are slightly sensitive to meson wave functions,agree with the experimental data.The analytical solution of the BK equation is reliable for description of exclusive vector meson productions in a certain range of Q^(2).展开更多
Nucleon properties and structure should be modified by short-range correlations(SRC)among nucleons.By analyzing SRC ratio data,we extract the mass of a nucleon in an SRC pair and the expected number of pn-SRC pairs in...Nucleon properties and structure should be modified by short-range correlations(SRC)among nucleons.By analyzing SRC ratio data,we extract the mass of a nucleon in an SRC pair and the expected number of pn-SRC pairs in deuterium,under the assumption that the SRC nucleon mass is universal for different nuclei.The nucleon mass of a two-nucleon SRC pair is m_(SRC)=852±18 MeV,and the number of pn-SRC pairs in deuterium is n^(d)_(SRC)=0.021±0.005.The mass deficit of the strongly overlapping nucleon can be explained by the trace anomaly contribution to the mass in QCD or alternatively by the vacuum energy in the MIT bag model.展开更多
基金supported by National Natural Science Foundation of China(Nos.12075326,11535014,11975017,12475191,11905092,12105132 and 12175039)Guangdong Basic and Applied Basic Research Foundation(No.2025A1515010669)+7 种基金Natural Science Foundation of Guangzhou(No.2024A04J6243)Fundamental Research Funds for the Central Universities(23xkjc017)in Sun Yat-sen UniversityBasic Research Conditions and Major Scientific Instrument and Equipment Research and Development Projects of the Ministry of Science and Technology(No.2022YFF0705602)the State Key Laboratory of Particle Detection and Electronics(SKLPDE-ZZ-202412)Natural Science Foundation of Shandong Province(No.2023HWYQ-010)the“Fundamental Research Funds for the Central Universities”at Southeast Universitythe National Development and Reform Commission of China(Large Research Infrastructures of 12th Five-Year Plan:China initiative Accelerator Driven System)(No.2017-000052-75-01-000590)Innovation Training Program for bachelor students in Sun Yat-sen University。
文摘The spontaneous conversion of muonium to antimuonium is an interesting charged lepton flavor violation phenomenon that offers a sensitive probe for potential new physics and serves as a tool to constrain the parameter space beyond the Standard Model.The Muonium-to-Antimuonium Conversion Experiment(MACE)was designed to utilize a high-intensity muon beam,a Michel electron magnetic spectrometer,a positron transport system,and a positron detection system to either discover or constrain this rare process with a conversion probability of O(10^(-13)).This article presents an overview of the theoretical framework and a detailed description of the experimental design for muonium-to-antimuonium conversion.
基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030301)。
文摘Exclusive vector meson production is an excellent probe for describing the structure of protons.In this study,based on the dipole model,the differential cross sections,total cross sections,and ratios of the longitudinal to transverse cross section of the J/ψandρ^(0)productions are calculated with the analytical solution of the Balitsky-Kovchegov(BK)equation.In addition,we consider the influences of two meson wave function models on the results.Our predictions,which are slightly sensitive to meson wave functions,agree with the experimental data.The analytical solution of the BK equation is reliable for description of exclusive vector meson productions in a certain range of Q^(2).
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030301)the National Science Foundation China(11305007)。
文摘Nucleon properties and structure should be modified by short-range correlations(SRC)among nucleons.By analyzing SRC ratio data,we extract the mass of a nucleon in an SRC pair and the expected number of pn-SRC pairs in deuterium,under the assumption that the SRC nucleon mass is universal for different nuclei.The nucleon mass of a two-nucleon SRC pair is m_(SRC)=852±18 MeV,and the number of pn-SRC pairs in deuterium is n^(d)_(SRC)=0.021±0.005.The mass deficit of the strongly overlapping nucleon can be explained by the trace anomaly contribution to the mass in QCD or alternatively by the vacuum energy in the MIT bag model.
