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arXiv 0706.0976hep-th
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从MHV图看单圈N=8超重力振幅

One-loop N=8 Supergravity Amplitudes from MHV Diagrams

Adele Nasti, Gabriele Travaglini

摘要:

本文讨论了用MHV图计算N=8超引力单圈振幅的问题。与Yang-Mills中胶子的MHV振幅不同,引力子的树能级MHV振幅在旋量变量中不是全纯的。为了将这些振幅扩展到壳外,并将它们作为顶点来构建循环,我们引入了与循环动量相关的旋量变量的某些位移。利用这个离壳规定,我们重新推导出四点MHV振幅的引力子在一个圈,在与已知的结果完全一致。我们还讨论了任意数量引力子的单圈MHV振幅情况的扩展。

英文摘要:

We discuss the calculation of one-loop amplitudes in N=8 supergravity using MHV diagrams. In contrast to MHV amplitudes of gluons in Yang-Mills, tree-level MHV amplitudes of gravitons are not holomorphic in the spinor variables. In order to extend these amplitudes off shell, and use them as vertices to build loops, we introduce certain shifts for the spinor variables associated to the loop momenta. Using this off-shell prescription, we rederive the four-point MHV amplitude of gravitons at one loop, in complete agreement with known results. We also discuss the extension to the case of one-loop MHV amplitudes with an arbitrary number of gravitons.

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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