Contribution to a conference proceedings/Internal Report

FZJ-2015-04986

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Connected and disconnected quark contributions to hadron spin

Chambers, A. J. (Corresponding author) ; Horsley, R. ; Nakamura, Y. ; Perlt, H. ; Pleiter, D. ; Rakow, P. E. L. ; Schierholz, G. ; Schiller, A.Extern* ; Stüben, H. ; Young, R. D. ; Zanotti, J. M.

2015

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Please use a persistent id in citations: http://hdl.handle.net/2128/10198

Report No.: PoS(LATTICE2014)165

Abstract: By introducing an external spin operator to the fermion action, the quark spin fractions of hadrons are determined from the linear response of the hadron energies using the Feynman-Hellmann (FH) theorem. At our SU(3)-flavour symmetric point, we find that the connected quark spin fractions are universally in the range 55-70\% for vector mesons and octet and decuplet baryons. There is an indication that the amount of spin suppression is quite sensitive to the strength of SU(3) breaking. We also present first preliminary results applying the FH technique to calculations of quark-line disconnected contributions to hadronic matrix elements of axial and tensor operators. At the SU(3)-flavour symmetric point we find a small negative contribution to the nucleon spin from disconnected quark diagrams, while the corresponding tensor matrix elements are consistent with zero.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 511 - Computational Science and Mathematical Methods (POF3-511) (POF3-511)

Appears in the scientific report 2015

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