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arXiv 0705.2632hep-thhep-phnucl-th
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从弦论和矢量优势研究重子动力学

Dynamics of Baryons from String Theory and Vector Dominance

Deog Ki Hong, Mannque Rho, Ho-Ung Yee, Piljin Yi

摘要:

我们考虑了坂井和杉本等人的弦论中的QCD全息模型,并研究了重子。在这个模型中,介子被集体地实现为五维U(N_F)=U(1)\times SU(N_F)$ Yang-Mills field and baryons are classically identified as $ SU(N_F)$ solitons with a unit Pontryagin number and $ N_c $ electric charges. The soliton is shown to be very small in the large 't Hooft coupling limit, allowing us to introduce an effective field $ { \cal B} $. Its coupling to the mesons are dictated by the soliton structure, and consists of a direct magnetic coupling to the $ SU(N_F)$ field strength as well as a minimal coupling to the $ U(N_F)$ gauge field. Upon the dimensional reduction, this effective action reproduces all interaction terms between nucleons and an infinite tower of mesons in a manner consistent with the large $ N_c$展开式.我们进一步发现,所有的电磁相互作用,通过全息处方从相同的有效作用推断,是由一个无限的矢量介子塔介导的,呈现重子电磁形状因子完全矢量主导。我们估计了核子-介子耦合和反常磁矩,与自然界比较。

英文摘要:

We consider a holographic model of QCD from string theory, a la Sakai and Sugimoto, and study baryons. In this model, mesons are collectively realized as a five-dimensional \$U(N_F)=U(1)\times SU(N_F)$ Yang-Mills field and baryons are classically identified as $SU(N_F)$ solitons with a unit Pontryagin number and $N_c$ electric charges. The soliton is shown to be very small in the large 't Hooft coupling limit, allowing us to introduce an effective field ${\cal B}$. Its coupling to the mesons are dictated by the soliton structure, and consists of a direct magnetic coupling to the $SU(N_F)$ field strength as well as a minimal coupling to the $U(N_F)$ gauge field. Upon the dimensional reduction, this effective action reproduces all interaction terms between nucleons and an infinite tower of mesons in a manner consistent with the large $N_c$ expansion. We further find that all electromagnetic interactions, as inferred from the same effective action via a holographic prescription, are mediated by an infinite tower of vector mesons, rendering the baryon electromagnetic form factors completely vector-dominated as well. We estimate nucleon-meson couplings and also the anomalous magnetic moments, which compare well with nature.

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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