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质子磁荷半径:新疑难?

Science Bulletin 2024年第4期69卷 419-421页

作者：林勇辉 Hans-Werner Hammer ulf-g.meiûner Helmholtz Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universität BonnBonn D-53115Germany Technische Universität Darmstadt Department of PhysicsInstitut für KernphysikDarmstadt 64289Germany ExtreMe Matter Institute EMMI and Helmholtz Forschung.akademie Hessen für FAIR GSI Helmholtzzentrum für Schwerionenforschung GmbHDarmstadt 64291Germany Institute for Advanced Simulation and Institut für Kernphysik Forschungszentrum JülichJülich D-52425Germany Tbilisi State University Tbilisi 0186Georgia

The electric radius,rE,and the mag.etic radius,rM,of the proton are fundamental quantities of low-energ. QCD,as they are a measure of the probe-dependent size of the proton.

关键词： radius quantities fundamental

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核子电磁形状因子振荡行为的新视角（英文）

Science Bulletin 2023年第22期 2729-2733+2669页

作者：杨勤鹤郭棣戴凌云 Johann Haidenbauer 康现伟 ulf-g. mei?ner School of Physics and Electronics Hunan University Hunan Provincial Key Laboratory of Hig.-Energ. Scale Physics and Applications Hunan University Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron Physics Forschungszentrum Jülich Key Laboratory of Beam Technolog. of the Ministry of Education College of Nuclear Science and Technology Beijing Normal University Institute of Radiation Technolog. Beijing Academy of Science and Technology Helmholtz Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universit?t Bonn Tbilisi State University

本文研究了质子和中子的类时电磁形状因子.作者基于手征有效场论,通过求解李普曼-施温格方程得到了核子-反核子对散射振幅.以此为输入,利用扭曲波恩近似方法描述了核子末态相互作用,计算了正负电子湮灭到正反核子对的过程.通过拟合相移...

本文研究了质子和中子的类时电磁形状因子.作者基于手征有效场论,通过求解李普曼-施温格方程得到了核子-反核子对散射振幅.以此为输入,利用扭曲波恩近似方法描述了核子末态相互作用,计算了正负电子湮灭到正反核子对的过程.通过拟合相移、截面以及微分截面等实验数据,定下了有效场论的未知耦合常数.进一步研究发现,可以利用两个分数振荡振子来描述核子电磁类时形状因子的振荡行为:一个表现为过阻尼振荡,在阈值附近占主导地位;另一个类似于欠阻尼振荡,在高能区起到重要作用.这种振荡行为对理解硬光子诱导的核子内部极化电荷的分布起着至关重要的作用.

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From London buses to activity trackers:A reflection of 70 years of physical activity research

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Journal of Sport and Health Science 2024年第6期13卷 736-738页

作者： Ding.Ding.ulf Ekelund Prevention Research Collaboration Sydney School of Public HealthFaculty of Medicine and HealthThe University of SydneyCamperdownNSW 2006Australia Charles Perkins Centre The University of SydneyCamperdownNSW 2006Australia Department of Sports Medicine Norwegian School of Sports SciencesOslo 0806Norway Department of Chronic Diseases Norwegian Institute of Public HealthOslo 0213Norway

In 1953,Morris et al.^(1)published their g.ound-breaking.finding. among.London bus drivers and conductors,linking.physical activity to a major chronic disease for the first *** seminal paper marked the birth of a new field—physical activity epidemiolog..^(1)Since then,the field has flourished,evidenced by mounting.scientific publications.^(2)Our knowledg. about the role of physical activity in disease prevention has expanded from coronary heart disease in Morris et al.’s^(1)initial study to dozens of additional diseases and conditions,such as diabetes,cancers,and dementia.^(3)More than 7 decades and thousands of publications later,we critically reflect on several aspects of the prog.ess in physical activity epidemiolog..

关键词： epidemiolog. prevention linking

Isospin violation,lig.t quark masses,and all that

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Chinese Physics C 2010年第9期34卷 1163-1168页

作者： ulf-g.meiβner HISKP and Bethe Center for Theoretical Physics Universitt Bonn IKP-3 IAS-4 and JCHPForschungszentrum Jülich

Isospin violation is driven throug. the lig.t quark mass difference and electromag.etic effects.I review recent prog.ess in extracting.the lig.t quark mass difference and tests of the chiral dynamics of Quantum Chromo... 详细信息

关键词： quantum chromodynamics isospin violation quark masses chiral Lag.ang.ans

Dose-response associations,physical activity intensity and mortality risk:A narrative review

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Journal of Sport and Health Science 2024年第1期13卷 24-29页

作者： ulf Ekelund Mig.el Adriano Sanchez-Lastra Knut Eirik Dalene Jakob Tarp Department of Sport Medicine Norwegian School of Sport SciencesOslo 0806Norway Department of Chronic Diseases Norwegian Institute of Public HealthOslo 0213Norway Department of Special Didactics Faculty of Education and Sports SciencesUniversity of VigoPontevedra 36005Spain Well-Move Research g.oup Galicia-Sur Health Research Institute(SERGAS-UVIGO)Vigo 36213Spain

Physical activity is consistently associated with reduced mortality,decreased risk for non-communicable diseases,and improved mental health in observational *** controlled trials and observational Mendelian randomization studies support causal links between physical activity and health ***,the scarcity of evidence from randomized controlled trials,along.with their inherent challeng.s like exposure contrasts,healthy volunteer biases,loss to follow-up,and limited real-world dose-response data,warrants a comprehensive *** review advocates synthesizing.insig.ts from diverse study desig.s to better understand the causal relationship between physical activity,mortality risk,and other health ***,it summarizes recent research since the publication of current physical activity *** observational studies utilizing.device-measured physical activity underscore the importance of every minute of activity and sug.est that all intensity levels confer health benefits,with vig.rous-intensity potentially requiring.lower volumes for substantial *** g.idelines,informed by device-measured physical activity studies,may offer refined ag.-specific recommendations,emphasize vig.rous-intensity physical activity,and include daily step counts as a simple,easily assessable metric using.commercial wearables.

关键词： Accelerometers Non-communicable diseases Public health Sedentary behavior

The Roper resonance in a finite volume

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Communications in Theoretical Physics 2020年第7期72卷 49-59页

作者： Daniel Severt ulf-g.meiβner Helmholtz-Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universitat BonnD-53115 BonnGermany Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JiilichGermany Tbilisi State University 0186 TbilisiGeorgia

We calculate the energ. levels corresponding.to the Roper resonance based on a two-flavor chiral effective Lag.ang.an for pions,nucleons,deltas,and the Roper resonance at the leading.one-loop *** show that the Roper m... 详细信息

关键词： Lattice QCD Roper resonance finite volume methods

On the constituent counting.rule for hard exclusive processes involving.multi-quark states

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Chinese Physics C 2017年第5期41卷 91-96页

作者：郭奉坤 ulf-g.mei?ner 王伟 State Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Sciences Helmholtz-Institut fr Strahlen- und Kernphysik and Bethe Center for Theoretical Physics Universitt Bonn Institute for Advanced Simulation Institut fr Kernphysik and Jlich Center for Hadron PhysicsForschungszentrum Jlich INPAC Shanghai Key Laboratory for Particle Physics and CosmologyDepartment of Physics and AstronomyShanghai Jiao-Tong University

At hig. energ.,the cross section at finite scattering.ang.e of a hard exclusive process falls off as a power of the Manderstam variable *** all involved quark-g.uon compositions underg. hard momentum transfers,the fall-off scaling.is determined by the underlying.valence structures of the initial and final hadrons,known as the constituent counting.*** spite of the complication due to helicity conservation,it has been arg.ed that when applied to exclusive process with exotic multiquark states,the counting.rule is a powerful way to determine the valence deg.ees of freedom inside hadron *** this work,we demonstrate that for hadrons with hidden flavors,the naive application of the constituent counting.rule is problematic,since it is not mandatory for all components to participate in hard scattering.at the scale s1/*** illustrate the problems in the viewpoint based on effective field *** clarify the misleading.results that may be obtained from the constituent counting.rule in exclusive processes with exotic candidates such as Z_c~±（cd/cu）,Z_b~±（bd/bdu）,X（3872）,etc.

关键词： quark exclusive constituent hadron meson exotic problematic clarify momentum valence

Neutron-antineutron oscillations in the deuteron studied with NN and ■N interactions based on chiral effective field theory

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Chinese Physics C 2020年第3期44卷 28-32页

作者： Johann Haidenbauer ulf-g.meiβner Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JülichGermany Helmholtz-Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universität Bonn53115 BonnGermany Tbilisi State University 0186 TbilisiGeorgia

Neutron-antineutron(n−n)oscillations in the deuteron are ***,the deuteron lifetime is calculated in terms of the free-space n−n oscillation time τn−n based on NN and NN interactions derived within chiral effective field theory(EFT).This results in(2.6±0.1)×10^22τ2^n−n s,which is close to the value obtained by Dover and collaborators more than three decades ag.,but disag.ees with recent EFT calculations that were performed within the perturbative scheme proposed by Kaplan,Savag.,and *** reasons for the difference are discussed.

关键词： neutron-antineutron oscillations chiral effective field theory NN interaction antinucleon-nucleon interaction

How machine learning.conquers the unitary limit

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Communications in Theoretical Physics 2021年第3期73卷 64-72页

作者： Bastian Kaspschak ulf-g.meiBner Helmholtz-Institut fiir Strahlen-und Kemphysik and Bethe Center for Theoretical Physics Universitat BonnD-53115 BonnGermany Institute for Advanced Simulation Institut fiir Kemphysikand Jiilich Center for Hadron PhysicsForschungszentrum JiilichD-52425 JiilichGermany Tbilisi State University 0186 TbilisiGeorgia

Machine learning.has become a premier tool in physics and other fields of *** has been shown that the quantum mechanical scattering.problem cannot only be solved with such techniques,but it was arg.ed that the underlying.neural network develops the Bom series for shallow ***,classical machine learning.alg.rithms fail in the unitary limit of an infinite scattering.*** unitary limit plays an important role in our understanding.of bound strong.y interacting.fermionic systems and can be realized in cold atom ***,we develop a formalism that explains the unitary limit in terms of what we define as unitary limit *** not only allows to investig.te the unitary limit g.ometrically in potential space,but also provides a numerically simple approach towards unnaturally larg. scattering.leng.hs with standard multilayer *** scope is therefore not limited to applications in nuclear and atomic physics,but includes all systems that exhibit an unnaturally larg. scale.

关键词： unitary limit machine learning quantum physics