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arXiv 1804.03094hep-ph
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SU(3)BChPT x 1/Nc中的重子质量和σ项

Baryon masses and σ-terms in SU(3) BChPT x 1/Nc

I. P. Fernando, J. M. Alarcon, J. L. Goity

摘要:

用手征展开和1/Nc展开相结合的有效理论研究了重子质量和核子σ项。特别强调了Gell-Mann-Okubo关系的偏差与超荷标量密度对应的σ项之间的联系。后者处于与质量组合相关的最低阶,质量组合的低值引起了σ项难题。结果表明,虽然核子σ项具有良好的低能展开,但质量组合受到夸克质量中大的高阶非解析修正的影响。加上对格点量子色动力学重子质量的分析,发现σπN=69(10)MeV,σs在其相对较大的不确定度范围内具有自然量值。

英文摘要:

Baryon masses and nucleon σ-terms are studied with the effective theory that combines the chiral and 1/Nc expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the σ-term corresponding to the scalar density associated with the hypercharge is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a σ- term puzzle. It is shown that while the nucleon σ-terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Adding to the analysis lattice QCD baryon masses, it is found that σπN=69(10) MeV and σs has natural magnitude within its relative large uncertainty.

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