来自第五维的电磁形状因子
Electromagnetic form factors from the fifth dimension
摘要：
我们分析了各种$U(1)_{EM}$形状因子的介子在强耦合的$\mathcal{N}=2$味版本的$\mathcal{N}=4$ $SYM$，成为共形的紫外线。夸克的质量打破了红外线的共形对称性，产生了一个质量间隙。在适当的极限下，引力对偶可以用$AdS_5\times S^5$中的探测$D7$ -膜来描述.通过研究$D7$涨落，我们找到了“介子有效理论”中的合适项，这使我们能够计算所需的形状因子，即$γπρ$和$γf_0ρ$跃迁形状因子。在大的$q^2$，我们发现与朴素部分子模型计数完全一致，这是量子色动力学和我们的模型在紫外线下的共形性质的结果。通过使用相同的工具，我们可以计算$γ^*γ^*π$形状因子。然而，这个通道更微妙，与QCD结果的比较更复杂。
英文摘要：
We analyse various $U(1)_{EM}$ form factors of mesons at strong coupling in an $\mathcal{N}=2$ flavored version of $\mathcal{N}=4$ $SYM$ which becomes conformal in the UV. The quark mass breaks the conformal symmetry in the IR and generates a mass gap. In the appropriate limit, the gravity dual is described in terms of probe $D7$-branes in $AdS_5\times S^5$. By studying the $D7$ fluctuations we find the suitable terms in a "meson effective theory" which allow us to compute the desired form factors, namely the $γπρ$ and $γf_0ρ$ transition form factors. At large $q^2$ we find perfect agreement with the naive parton model counting, which is a consequence of the conformal nature of both QCD and our model in the UV. By using the same tools, we can compute the $γ^*γ^*π$ form factor. However this channel is more subtle and comparisons to the QCD result are more involved.
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。
