Journal Article

PreJuSER-21703

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png A lattice study of the strangeness content of the nucleon

Bali, G. S. ; Collins, S. ; Göckeler, M. ; Horsley, R. ; Nakamura, Y. ; Nobile, A. ; Pleiter, D.FZJ* ; Rakow, P. E. L. ; Sternbeck, A. ; Schäfer, A. ; Schierholz, G. ; Zanotti, J. M.

2012
Pergamon Press Oxford [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.ppnp.2012.01.012

Abstract: We determine the quark contributions to the nucleon spin Delta s, Delta u and Ad as well as their contributions to the nucleon mass, the a-terms. This is done by computing both, the quark line connected and disconnected contributions to the respective matrix elements, using the non-perturbatively improved Sheikholeslami-Wohlert Wilson Fermionic action. We simulate n(F) = 2 mass degenerate sea quarks with a pion mass of about 285 MeV and a lattice spacing a approximate to 0.073 fm. The renormalization of the matrix elements involves mixing between contributions from different quark flavours. The pion-nucleon a-term is extrapolated to physical quark masses exploiting the sea quark mass dependence of the nucleon mass. We obtain the renormalized value sigma(pi N) = (38 +/- 12) MeV at the physical point and the strangeness fraction f(Ts) = sigma s/m(N) = 0.012(14)(-3)(+10) at our larger than physical sea quark mass. For the strangeness contribution to the nucleon spin we obtain Delta s ((MS)) over bar(root 7.4 GeV) = -0.020(10)(1). (C) 2012 Published by Elsevier B.V.

Keyword(s): J ; Lattice QCD (auto) ; Nucleon structure (auto) ; Nucleon spin (auto) ; sigma-term (auto) ; Strangeness (auto)

Note: This work was supported by the European Union (grant 238353, ITN STRONGnet) and by the DFG SFB/Transregio 55. S.C. is supported by the Claussen-Simon-Foundation (Stifterverband fur die Deutsche Wissenschaft), A.St. by the EU IRG grant 256594 and J.Z. by the Australian Research Council grant FT100100005. Computations were performed on the SFB/TR55 QPACE supercomputers, the BlueGene/P (JuGene) and the Nehalem cluster (JuRoPA) of the JSC (Julich), the IBM BlueGene/L at the EPCC (Edinburgh), the SGI Altix ICE machines at HLRN (Berlin/Hannover) and Regensburg's Athene HPC cluster. The Chroma software suite [24] was used extensively in this work.

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Contributing Institute(s):

1. Jülich Supercomputing Centre (JSC)

Research Program(s):

1. Scientific Computing (FUEK411) (FUEK411)
2. 411 - Computational Science and Mathematical Methods (POF2-411) (POF2-411)
3. STRONGNET - Strong Interaction Supercomputing Training Network (238353) (238353)
4. PRECISION LATTICEQCD - Precision lattice QCD calculations (256594) (256594)

Appears in the scientific report 2012

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Database coverage:
JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection ; Zoological Record

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