Aspects of Symmetry in Scattering Amplitudes

• Main Authors: Wei-Ming Chen, 陳韋名
• Other Authors: Pei-Ming Ho
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/31122286218922735808

博士 === 國立臺灣大學 === 物理研究所 === 103 === The development of modern on-shell methods for scattering amplitudes allows us to construct scattering amplitudes without the knowledge of a Lagrangian. In this thesis, various aspects of symmetry in scattering amplitudes are studied in this content. In Part 1, we review the hidden dual superconformal symmetry in three-dimensional Chern-Simons-matter theory and utilize it to construct the amplitudes up to two-loop. In Part 2, we discuss the rational terms of the parity-odd part of one-loop amplitudes in chiral gauge theories. The presence of rational terms is connected to the requirement of locality. Anomalies are then recast as the result of a inconsistent rational term with both locality and unitarity. Finally, we establish the soft theorems for double-soft-scalar-limit in three- and four-dimensional supergravity theories. Surprisingly, the amplitudes also have a universal pattern under double-soft-fermion-limit, there exists implicitly a new symmetry. As a preliminary application of the soft theorem to three-dimensional maximal supergravity, we rule out the direct dimensional reduction of D^8R^4 out as a valid counter term.