Theory Colloquium

Wilson Coefficients and Natural Zeros from the On-Shell Viewpoint

by Benedict von Harling (IFAE Barcelona)

SR 2, build. 2a (DESY Hamburg)

SR 2, build. 2a

DESY Hamburg


On-shell methods have proven to be very useful for calculations in effective field theories. In this seminar, I discuss how these methods allow one to simplify the calculation of finite contributions to Wilson coefficients from heavy particles. I apply this technique to the calculation of the Wilson coefficients of operators contributing to g − 2 and Higgs decays to photons, and show how the finite contributions can be obtained from the product of tree-level amplitudes. In certain cases, due to a parity symmetry of these amplitudes, the total contribution to the Wilson coefficients adds up to zero, as previously found in the literature. The method that I present allows one to search for new natural zeros, as well as to obtain non-zero contributions in a straightforward way.