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7篇 您的检索式:作者名="Craig D.Roberts"
    题名 作者 年代 出处 被引量
1Collective Perspective on Advances in Dyson–Schwinger Equation QCD显示文摘We survey contemporary studies of hadrons and strongly interacting quarks using QCD's Dyson-Schwinger equations, addressing the following aspects: confinement and dynamical chiral symmetry breaking; the hadron spectrum; hadron elastic and transition form factors, from small-to large-Q2; parton distribution functions; the physics of hadrons containing one or more heavy quarks; and properties of the quark gluon plasma.Adnan Bashir Ian C.Clet Bruno El-Bennich Craig D.Roberts Peter C.Tandy 2012Communications in Theoretical Physics2012,58,7:2
2Pauli Radius of the Proton显示文摘Using a procedure based on interpolation via continued fractions supplemented by statistical sampling,we analyze proton magnetic form factor data obtained via electron+proton scattering on Q^(2)∈[0.027,0.55]GeV^(2)with the goal of determining the proton magnetic radius.The approach avoids assumptions about the function form used for data interpolation and ensuing extrapolation onto Q^(2)■0 for extraction of the form factor slope.In this way,we find r_(M)=0.817(27)fm.Regarding the difference between proton electric and magnetic radii calculated in this way,extant data are seen to be compatible with the possibility that the slopes of the proton Dirac and Pauli form factors,F1,2(Q^(2)),are not truly independent observables;to wit,the difference F_(1)’(0)-F_(2)’(0)/κp=[1+Kp]/[4 m_(p)^(2)],viz.,the proton Foldy term.崔著钫 Daniele Binosi Craig D.Roberts Sebastian M.Schmidt 2021Chinese Physics Letters2021,38,12:0
3Resolving the Bethe–Salpeter Kernel显示文摘A novel method for constructing a kernel for the meson bound-state problem is described.It produces a closed form that is symmetry-consistent(discrete and continuous)with the gap equation defined by any admissible gluon-quark vertex,Γ.Applicable even when the diagrammatic content ofΓis unknown,the scheme can foster new synergies between continuum and lattice approaches to strong interactions.The framework is illustrated by showing that the presence of a dressed-quark anomalous magnetic moment inΓ,an emergent feature of strong interactions,can remedy many defects of widely used meson bound-state kernels,including the mass splittings between vector and axial-vector mesons and the level ordering of pseudoscalar and vector meson radial excitations.秦思学 Craig D.Roberts 2021Chinese Physics Letters2021,38,7:0
4All-Orders Evolution of Parton Distributions:Principle,Practice,and Predictions显示文摘Parton distribution functions(PDFs)are defining expressions of hadron structure.Exploiting the role of effective charges in quantum chromodynamics,an algebraic scheme is described which,given any hadron’s valence parton PDFs at the hadron scale,delivers predictions for all its PDFs(unpolarized and polarized)at any higher scale.The scheme delivers results that are largely independent of both the value of the hadron scale and the pointwise form of the charge;and,inter alia,enables derivation of a model-independent identity that relates the strength of the proton’s gluon helicity PDF,ΔG_(p)ζ,to that of the analogous singlet polarized quark PDF and valence quark momentum fraction.Using available data fits and theory predictions,the identity yieldsΔG_(p)(ζC=√3 GeV)=1.48(10).It furthermore entails that the measurable quark helicity contribution to the proton spin is a_(op)^(ζC)=0.32(3),thereby reconciling contemporary experiment and theory.尹佩林 徐胤禛 崔著钫 Craig D.Roberts José Rodríguez-Quintero 2023Chinese Physics Letters2023,40,9:0
5Regarding the Distribution of Glue in the Pion显示文摘Understanding why the scale of emergent hadron mass is obvious in the proton but hidden in the pion may rest on mapping the distribution functions(DFs)of all partons within the pion and comparing them with those in the proton;and since glue provides binding in quantum chromodynamics,the glue DF could play a special role.Producing reliable predictions for the proton’s DFs is difficult because the proton is a three-valence-body bound-state problem.As sketched herein,the situation for the pion,a two-valence-body problem,is much better,with continuum and lattice predictions for the valence-quark and glue DFs in agreement.This beginning of theory alignment is timely because experimental facilities now either in operation or planning promise to realize the longstanding goal of providing pion targets,thereby enabling precision experimental tests of rigorous theory predictions concerning Nature’s most fundamental Nambu-Goldstone bosons.常雷 Craig D.Roberts 2021Chinese Physics Letters2021,38,8:0
6Hadron and light nucleus radii from electron scattering显示文摘Conceptually,radii are amongst the simplest Poincaré-invariant properties that can be associated with hadrons and light nuclei.Accurate values of these quantities are necessary so that one may judge the character of putative solutions to the strong interaction problem within the Standard Model.However,limiting their ability to serve in this role,recent measurements and new analyses of older data have revealed uncertainties and imprecisions in the radii of the proton,pion,kaon,and deuteron.In the context of radius measurement using electron+hadron elastic scattering,the past decade has shown that reliable extraction requires minimisation of bias associated with practitioner-dependent choices of data fitting functions.Different answers to that challenge have been offered;and this perspective describes the statistical Schlessinger point method(SPM),in unifying applications to proton,pion,kaon,and deuteron radii.Grounded in analytic function theory,independent of assumptions about underlying dynamics,free from practitioner-induced bias,and applicable in the same form to diverse systems and observables,the SPM returns an objective expression of the information contained in any data under consideration.Its robust nature and versatility make it suitable for use in many branches of experiment and theory.崔著钫 Daniele Binosi Craig D.Roberts Sebastian M.Schmidt 2022Chinese Physics C2022,46,12:0
7Valence Quark Ratio in the Proton显示文摘Beginning with precise data on the ratio of structure functions in deep inelastic scattering(DIS)from ^3He and ^3H,collected on the domain 0.19≤xB≤0.83,where xBis the Bjorken scaling variable,we employ a robust method for extrapolating such data to arrive at a model-independent result for the xB=1 value of the ratio of neutron and proton structure functions.Combining this with information obtained in analyses of DIS from nuclei,corrected for target-structure dependence,we arrive at a prediction for the proton valence-quark ratio:d_(v)/u_(v)|_(xB→1)=0.230(57).Requiring consistency with this result presents a challenge to many descriptions of proton structure.崔著钫 高飞 Daniele Binosi 常雷 Craig D.Roberts Sebastian M.Schmidt 2022Chinese Physics Letters2022,39,4:0
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