A lattice study of the strangeness content of the nucleon

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• 作者：G.S. Bali^a ; ^{gunnar.bali@physik.uni-regensburg.de} ; S. Collins^a ; M. Gö ; ckeler^a ; R. Horsley^b ; Y. Nakamura^c ; A. Nobile^a ; D. Pleiter^d ; ^a ; P.E.L. Rakow^e ; A. Sternbeck^a ; A. Schä ; fer^a ; G. Schierholz^f ; J.M. Zanotti^g ; (QCDSF Collaboration)
• 关键词：Lattice QCD ; Nucleon structure ; Nucleon spin ; 蟽-term ; Strangeness
• 刊名：Progress in Particle and Nuclear Physics
• 出版年：2012
• 期刊代码：64_01466410
• 类别：ph
• 出版时间：April, 2012
• 卷：67
• 期：2
• 页码：467-472
• 文件大小：284 K

摘要

We determine the quark contributions to the nucleon spin , and as well as their contributions to the nucleon mass, the -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 mass degenerate sea quarks with a pion mass of about 285聽MeV and a lattice spacing 聽fm. The renormalization of the matrix elements involves mixing between contributions from different quark flavours. The pion-nucleon -term is extrapolated to physical quark masses exploiting the sea quark mass dependence of the nucleon mass. We obtain the renormalized value 聽MeV at the physical point and the strangeness fraction at our larger than physical sea quark mass. For the strangeness contribution to the nucleon spin we obtain .