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arXiv 0705.2113hep-thhep-ph
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强耦合N=4 SYM中的散射振幅与AdS中半经典弦的散射

Scattering amplitudes in strongly coupled N=4 SYM from semiclassical strings in AdS

Steven Abel, Stefan Forste, Valentin V. Khoze

摘要:

最近在arXiv:0705.0303中,Alday和Maldacena给出了一个弦论公式,用AdS/CFT对应计算强耦合下N=4超对称规范理论的(所有)平面振幅。这些振幅由经典弦解决定,并包含一个涉及经典弦作用的普适指数因子。在规范理论方面,强耦合时的微扰振幅表达式以前只针对外部粒子的特定螺旋度提出--最大螺旋度违反或MHV振幅。这些结果来自Bern、Dixon和Smirnov对N=4 SYM中MHV振幅的指数拟合。在本文中,我们研究的振幅依赖于螺旋度和粒子类型的外部状态。我们考虑了弦振幅的前因子,并给出了强耦合下的前因子应与同一过程的杨-米尔斯树级振幅相同的论据。这意味着N=4 SYM中的散射振幅在强耦合极限下显著简化。从我们的建议可以得出,在这个极限中,所有(MHV和非MHV)n点振幅由(已知的)树级杨-米尔斯结果乘以螺旋度无关(和粒子类型无关)的普适指数给出。

英文摘要:

Very recently in arXiv:0705.0303 Alday and Maldacena gave a string theory prescription for computing (all) planar amplitudes in N=4 supersymmetric gauge theory at strong coupling using the AdS/CFT correspondence. These amplitudes are determined by a classical string solution and contain a universal exponential factor involving the action of the classical string. On the gauge theory side, expressions for perturbative amplitudes at strong coupling were previously proposed only for specific helicities of external particles -- the maximally helicity violating or MHV amplitudes. These follow from the exponential ansatz of Bern, Dixon and Smirnov for MHV amplitudes in N=4 SYM. In this paper we examine the amplitudes dependence on helicities and particle-types of external states. We consider the prefactor of string amplitudes and give arguments suggesting that the prefactor at strong coupling should be the same as the Yang-Mills tree-level amplitude for the same process. This implies that scattering amplitudes in N=4 SYM simplify dramatically in the strong coupling limit. It follows from our proposal that in this limit all (MHV and non-MHV) n-point amplitudes are given by the (known) tree-level Yang-Mills result times the helicity-independent (and particle-type-independent) universal exponential.

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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