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arXiv 0901.2055hep-ph
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重子谱学

Baryon spectroscopy

Eberhard Klempt, Jean-Marc Richard

摘要:

已知的重子和重子共振大约有120种,从含有$u$和$d$轻夸克成分的丰富核子到最近发现的$Ω_b^-=bss$和每代含有一个夸克的$Ξ_b^-=bsd$。尽管有如此多的状态,导致激发光谱的潜在机制还不清楚。重夸克重子缺乏已知的自旋宇称。在轻夸克部分,夸克模型计算在解释低质量激发谱方面取得了相当大的成功,但一些重要的方面,如正宇称和负宇称重子激发的质量简并度还没有得到令人满意的理解。在1.8 GeV以上的高质量下,夸克模型预测每个质量间隔的共振密度非常高,但没有观察到。在这篇评论中,问题被确定区分不同的观点的共振谱;前景讨论如何在重子光谱学的开放性问题可能会找到答案,目前在各个实验室进行的光和电生产实验。

英文摘要:

About 120 baryons and baryon resonances are known, from the abundant nucleon with $u$ and $d$ light-quark constituents up to the recently discovered $Ω_b^-=bss$, and the $Ξ_b^-=bsd$ which contains one quark of each generation. In spite of this impressively large number of states, the underlying mechanisms leading to the excitation spectrum are not yet understood. Heavy-quark baryons suffer from a lack of known spin-parities. In the light-quark sector, quark-model calculations have met with considerable success in explaining the low-mass excitations spectrum but some important aspects like the mass degeneracy of positive-parity and negative-parity baryon excitations are not yet satisfactorily understood. At high masses, above 1.8 GeV, quark models predict a very high density of resonances per mass interval which is not observed. In this review, issues are identified discriminating between different views of the resonance spectrum; prospects are discussed how open questions in baryon spectroscopy may find answers from photo- and electro-production experiments which are presently carried out in various laboratories.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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