%0 Journal Article
%A Bali, G.S.
%A Collins, S.
%A Göckeler, M.
%A Horsley, R.
%A Nakamura, Y.
%A Nobile, A.
%A Pleiter, D.
%A Rakow, P.E.L.
%A Sternbeck, A.
%A Schäfer, A.
%A Schierholz, G.
%A Zanotti, J.M.
%T A lattice study of the strangeness content of the nucleon
%J Progress in particle and nuclear physics
%V 67
%@ 0146-6410
%C Oxford [u.a.]
%I Pergamon Press
%M PreJuSER-21703
%P 467 - 472
%D 2012
%Z 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.
%X 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.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000303282200062
%R 10.1016/j.ppnp.2012.01.012
%U https://juser.fz-juelich.de/record/21703