Symmetries and analytic properties of scattering amplitudes in N=4 SYM theory - High Energy Physics - TheoryReport as inadecuate




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Abstract: In addition to the superconformal symmetry of the underlying Lagrangian, thescattering amplitudes in planar N=4 super-Yang-Mills theory exhibit a new, dualsuperconformal symmetry. We address the question of how powerful thesesymmetries are to completely determine the scattering amplitudes. We use theexample of the NMHV superamplitudes to show that the combined action ofconventional and dual superconformal symmetries is not sufficient to fix allthe freedom in the tree-level amplitudes. We argue that the additionalinformation needed comes from the study of the analytic properties of theamplitudes. The requirement of absence of spurious singularities, together withthe correct multi-particle singular behavior, determines the unique linearcombination of superinvariants corresponding to the n-particle NMHVsuperamplitude. The same result can be obtained recursively, by relating the n-and n-1-particle amplitudes in the singular collinear limit. We alsoformulate constraints on the loop corrections to the superamplitudes, followingfrom the analytic behavior in the above limits. We then show that theholomorphic anomaly of the tree amplitudes leads to the breakdown of dualPoincare supersymmetry which is equivalent to ordinary special conformalsupersymmetry of the ratio of the NMHV and MHV superamplitudes at one-looplevel, but this anomaly does not affect dual conformal symmetry.



Author: G.P.Korchemsky, E.Sokatchev

Source: https://arxiv.org/







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