Effective field theory of the electroweak sector

effective field theory;electroweak;anomalous couplings;unitarity;one-loop

Mebane, Harrison

关键词: effective field theory;    electroweak;    anomalous couplings;    unitarity;    one-loop;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/44370/Harrison_Mebane.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Effective field theory is a model-independent way to search for indirect effects of new physics.It has many advantages over the traditional anomalous couplings framework.In particular, gauge invariance makes possible the calculation of loop corrections.Furthermore, the issue of unitarity violation is shown to be irrelevant in an effective field theory.There are nine dimension-six operators which generate corrections to precision electroweak quantities through gauge boson propagators.I start with an analysis involving just two operators contributing at one loop in which I show that loop calculations, and the renormalization program in particular, can be carried out in a straightforward manner using effective field theory.I compare this to previous analyses and show that the methods presented here yield more accurate bounds on loop-level operator coefficients.I finish with a global analysis of the full set of nine operators.Bounds are presented on the linearly-independent combinations of the operators.The four operators which affect precision electroweak observables at tree-level are shown to absorb all divergences from the five operators contributing only at loop-level.The bounds are found to be considerably weaker than existing bounds from collider data.