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Updated: Apr 18, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Singularity structure of maximally supersymmetric scattering amplitudes
Nima Arkani-Hamed1, Jacob L Bourjaily2, Freddy Cachazo3
1School of Natural Sciences, Institute for Advanced Study, Princeton, New Jersey 08540, USA.
Loop amplitudes in maximally supersymmetric Yang-Mills theory (SYM) beyond the planar limit exhibit structures similar to the planar theory. The four-particle amplitude shows logarithmic singularities and no poles at infinity, indicating UV finiteness.
Area of Science:
- High-energy physics
- Quantum field theory
- Supersymmetry
Background:
- The study of scattering amplitudes in quantum field theories is crucial for understanding fundamental interactions.
- Maximally supersymmetric Yang-Mills theory (N=4 SYM) is a key theoretical laboratory due to its rich mathematical structure and potential connections to other theories.
- Understanding the behavior of amplitudes beyond the planar limit is essential for a complete picture.
Purpose of the Study:
- To investigate the properties of loop amplitudes in N=4 SYM beyond the planar limit.
- To determine if non-planar amplitudes share the remarkable structures observed in planar N=4 SYM.
- To explore the implications of these findings for maximal supergravity (N=8 SUGRA).
Main Methods:
- Calculation of four-particle scattering amplitudes in N=4 SYM up to two-loop order.
- Analysis of the singularity structure of these amplitudes, specifically looking for logarithmic singularities and poles at infinity.
- Comparison of the calculated amplitudes with known properties of the planar theory, such as uniform transcendentality.
Main Results:
- Evidence presented suggests that loop amplitudes in full N=4 SYM beyond the planar limit share structures with the planar theory.
- Specifically, the four-particle amplitude at two loops exhibits only logarithmic singularities.
- The amplitude is also found to be free of poles at infinity, consistent with uniform transcendentality and UV finiteness.
Conclusions:
- The findings indicate that the remarkable structures of planar N=4 SYM persist beyond the planar limit, at least up to two loops.
- These properties are closely linked to uniform transcendentality and the ultraviolet (UV) finiteness of the theory.
- The results have potential implications for understanding the structure of maximal supergravity (N=8 SUGRA).
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