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
We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-ly...We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.展开更多
Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the l...Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the last”SM particle.展开更多
最近HERA发现 l q共振态可能是e+ d共振,该事例非标准模型(SM)所预期,与亚夸克层次有关.用价-海亚夸克混合模型和Preon模型给出的"编外"粒子研究 l q共振态的物理机制,结果发现:产生 l q共振的物理基础是由于"编外"...最近HERA发现 l q共振态可能是e+ d共振,该事例非标准模型(SM)所预期,与亚夸克层次有关.用价-海亚夸克混合模型和Preon模型给出的"编外"粒子研究 l q共振态的物理机制,结果发现:产生 l q共振的物理基础是由于"编外"玻色子中存在具有B+23物质性质的"反轻子型夸克",在反轻子和夸克之间传递相互作用的是具有ε物质性质的"编外"玻色子,在ε物质的相互交换下 e d共振与 νe u共振可以相互转变,并与早前的中微子统一模型、新名古屋模型相符.展开更多
INFOCUS|JUNO Formally Comes into Operation A new-generation large-scale neutrino experiment,the Jiangmen Underground Neutrino Observatory(JUNO)formally came into operation and started collecting data in late August.
The tensor force changes the nuclear shell structure and thus may result in underlying influence of the collectivity and decay properties of the nucleus.We carefully examined the impact of the monopole and multipole e...The tensor force changes the nuclear shell structure and thus may result in underlying influence of the collectivity and decay properties of the nucleus.We carefully examined the impact of the monopole and multipole effects originating from the tensor force on both the collectivity and the matrix element for the neutrinoless double-β(0νββ)decay,using the generatorcoordinate method with an effective interaction.To analyze the effect of the tensor force,we employed an effective Hamiltonian associated with the monopole-based universal interaction that explicitly consists of the central,tensor,and spin-orbit coupling terms.The interferences among the shell structure,quadrupole collectivity,nucleon occupancy,and 0νββmatrix elements were analyzed in detail.A better understanding of the tensor force would be of great importance in reducing the theoretical uncertainty in 0νββnuclear matrix element calculations.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supported by the National Key Research and Development Program of China(Grant No.2022YFA1602501)the National Natural Science Foundation of China(Grant No.12011530060)+1 种基金supported solely by the Russian Science Foundation(Grant No.22-12-00043)supported by the Chinese Academy of Sciences(CAS)Presidents International Fellowship Initiative(PIFI)(Grant Nos.2018VMB0016 and 2022VMC0002),respectively。
文摘We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.
文摘Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the last”SM particle.
文摘最近HERA发现 l q共振态可能是e+ d共振,该事例非标准模型(SM)所预期,与亚夸克层次有关.用价-海亚夸克混合模型和Preon模型给出的"编外"粒子研究 l q共振态的物理机制,结果发现:产生 l q共振的物理基础是由于"编外"玻色子中存在具有B+23物质性质的"反轻子型夸克",在反轻子和夸克之间传递相互作用的是具有ε物质性质的"编外"玻色子,在ε物质的相互交换下 e d共振与 νe u共振可以相互转变,并与早前的中微子统一模型、新名古屋模型相符.
文摘INFOCUS|JUNO Formally Comes into Operation A new-generation large-scale neutrino experiment,the Jiangmen Underground Neutrino Observatory(JUNO)formally came into operation and started collecting data in late August.
基金supported by the National Natural Science Foundation of China(No.12275369)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.22qntd3101)the Guangdong Major Project of Basic and Applied Basic Research(2021B0301030006)。
文摘The tensor force changes the nuclear shell structure and thus may result in underlying influence of the collectivity and decay properties of the nucleus.We carefully examined the impact of the monopole and multipole effects originating from the tensor force on both the collectivity and the matrix element for the neutrinoless double-β(0νββ)decay,using the generatorcoordinate method with an effective interaction.To analyze the effect of the tensor force,we employed an effective Hamiltonian associated with the monopole-based universal interaction that explicitly consists of the central,tensor,and spin-orbit coupling terms.The interferences among the shell structure,quadrupole collectivity,nucleon occupancy,and 0νββmatrix elements were analyzed in detail.A better understanding of the tensor force would be of great importance in reducing the theoretical uncertainty in 0νββnuclear matrix element calculations.
