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arXiv · 0705.2632

Dynamics of Baryons from String Theory and Vector Dominance

Deog Ki Hong·Mannque Rho·Ho-Ung Yee·Piljin Yi
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Abstract

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.

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Deog Ki Hong, Mannque Rho, Ho-Ung Yee, Piljin Yi. 2009-03-10. Dynamics of Baryons from String Theory and Vector Dominance. https://doi.org/10.1088/1126-6708%2F2007%2F09%2F063

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