Weak separation, positivity and extremal Yangian invariants

Abstract We classify all positive n-particle NkMHV Yangian invariants in N $$ \mathcal{N} $$ = 4 YangMills theory with n = 5k, which we call extremal because none exist for n > 5k. We show that this problem is equivalent to that of enumerating plane cactus graphs with k pentagons. We use the know...

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Bibliographic Details
Main Authors: Luke Lippstreu, Jorge Mago, Marcus Spradlin, Anastasia Volovich
Format: Article
Language:English
Published: SpringerOpen 2019-09-01
Series:Journal of High Energy Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/JHEP09(2019)093