Four-point Amplitudes in N=8 Supergravity and Wilson Loops - High Energy Physics - TheoryReportar como inadecuado

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Abstract: Prompted by recent progress in the study of N=4 super Yang-Mills amplitudes,and evidence that similar approaches might be relevant to N=8 supergravity, weinvestigate possible iterative structures and applications of Wilson looptechniques in maximal supergravity. We first consider the two-loop, four-pointMHV scattering amplitude in N=8 supergravity, confirming that the infrareddivergent parts exponentiate, and we give the explicit expression whichrepresents the failure for this to occur for the finite part. We observe thateach term in the expansion of the one- and two-loop amplitudes in thedimensional regularisation parameter epsilon has a uniform degree oftranscendentality. We then turn to consider Wilson loops in supergravity,showing that a natural definition of the loop, involving the Christoffelconnection, fails to reproduce the one-loop amplitude. An alternativeexpression, which involves the metric explicitly, is shown to have a closerelationship with the physical amplitude. We find that in a gauge in which thecusp diagrams vanish, the remaining diagrams for this Wilson loop correctlygenerate the full one-loop, four-point N=8 supergravity amplitude.

Autor: Andreas Brandhuber, Paul Heslop, Adele Nasti, Bill Spence, Gabriele Travaglini


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