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Full-Text Articles in Physics
Sea Quarks Contribution To The Nucleon Magnetic Moment And Charge Radius At The Physical Point, Raza Sabbir Sufian, Yi-Bo Yang, Jian Liang, Terrence Draper, Keh-Fei Liu
Sea Quarks Contribution To The Nucleon Magnetic Moment And Charge Radius At The Physical Point, Raza Sabbir Sufian, Yi-Bo Yang, Jian Liang, Terrence Draper, Keh-Fei Liu
Physics and Astronomy Faculty Publications
We report a comprehensive analysis of the light and strange disconnected-sea quarks contribution to the nucleon magnetic moment, charge radius, and the electric and magnetic form factors. The lattice QCD calculation includes ensembles across several lattice volumes and lattice spacings with one of the ensembles at the physical pion mass. We adopt a model-independent extrapolation of the nucleon magnetic moment and the charge radius. We have performed a simultaneous chiral, infinite volume, and continuum extrapolation in a global fit to calculate results in the continuum limit. We find that the combined light and strange disconnected-sea quarks contribution to the nucleon …
Lattice Calculation Of Nucleon Isovector Axial Charge With Improved Currents, Jian Liang, Yi-Bo Yang, Keh-Fei Liu, Andrei Alexandru, Terrence Draper, Raza Sabbir Sufian
Lattice Calculation Of Nucleon Isovector Axial Charge With Improved Currents, Jian Liang, Yi-Bo Yang, Keh-Fei Liu, Andrei Alexandru, Terrence Draper, Raza Sabbir Sufian
Physics and Astronomy Faculty Publications
We employ dimension-4 operators to improve the local vector and axial-vector currents and calculate the nucleon isovector axial coupling g3A with overlap valence on 2 + 1-flavor domain wall fermion (DWF) sea. Using the equality of g3A from the spatial and temporal components of the axial-vector current as a normalization condition, we find that g3A is increased by a few percent towards the experimental value. The excited-state contamination has been taken into account with three time separations between the source and sink. The improved axial charges g3A(24I) = 1.22(4)(3) …
Glue Spin And Helicity In The Proton From Lattice Qcd, Yi-Bo Yang, Raza Sabbir Sufian, Andrei Alexandru, Terrence Draper, Michael J. Glatzmaier, Keh-Fei Liu, Yong Zhao
Glue Spin And Helicity In The Proton From Lattice Qcd, Yi-Bo Yang, Raza Sabbir Sufian, Andrei Alexandru, Terrence Draper, Michael J. Glatzmaier, Keh-Fei Liu, Yong Zhao
Physics and Astronomy Faculty Publications
We report the first lattice QCD calculation of the glue spin in the nucleon. The lattice calculation is carried out with valence overlap fermions on 2 + 1 flavor domain-wall fermion gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin SG in the Coulomb gauge in the modified minimal subtraction (MS¯) scheme is obtained with one-loop perturbative matching. We find the results fairly insensitive to lattice spacing and quark masses. We also find that the proton momentum dependence of SG in the range 0 ≤ |p …
Locality And Efficient Evaluation Of Lattice Composite Fields: Overlap-Based Gauge Operators, Andrei Alexandru, Ivan Horváth
Locality And Efficient Evaluation Of Lattice Composite Fields: Overlap-Based Gauge Operators, Andrei Alexandru, Ivan Horváth
Physics and Astronomy Faculty Publications
We propose a novel general approach to locality of lattice composite fields, which in case of QCD involves locality in both quark and gauge degrees of freedom. The method is applied to gauge operators based on the overlap Dirac matrix elements, showing for the first time their local nature on realistic path-integral backgrounds. The framework entails a method for efficient evaluation of such nonultralocal operators, whose computational cost is volume independent at fixed accuracy, and only grows logarithmically as this accuracy approaches zero. This makes computation of useful operators, such as overlap-based topological density, practical. The key notion underlying these …
Nonperturbative Evolution Of Parton Quasi-Distributions, A. V. Radyushkin
Nonperturbative Evolution Of Parton Quasi-Distributions, A. V. Radyushkin
Physics Faculty Publications
Using the formalism of parton virtuality distribution functions (VDFs) we establish a connection between the transverse momentum dependent distributions (TMDs) F(x,k2⊥) and quasi-distributions (PQDs) Q(y,p3) introduced recently by X. Ji for lattice QCD extraction of parton distributions f(x). We build models for PQDs from the VDF-based models for soft TMDs, and analyze the p3 dependence of the resulting PQDs. We observe a strong nonperturbative evolution of PQDs for small and moderately large values of p3 reflecting the transverse momentum dependence of TMDs. Thus, the study of PQDs on the lattice …