UC San Diego

Electroweak Sudakov logarithms at high energy, of the form ($$alpha$$/sin² $$theta$$w)̂n loĝm s/M_\{Z,W\}̂2, are summed using effective theory methods. The corrections are computed to processes involving two external fermionic or scalar particles, first in a spontaneously broken SU(2) gauge theory and then in the standard model. The results include non-zero particle masses, such as the t-quark mass, electroweak mixing effects which lead to unequal W and Z masses, and radiative Higgs corrections proportional to the Yukawa couplings. We show that the matching at the scale M_\{W,Z\} has a term at most linear in log s/ $$mu$$² to all orders. The effective theory formalism is compared with, and extends, previous work based on infrared evolution equations. Finally corrections to processes involving two external gauge bosons are computed in the broken SU(2) theory for both transverse and then longitudinal polarizations. The later will require the calculation of the multiplication factor $$epsilon$$, which relates the amplitude for longitudinal gauge boson production to Goldstone boson production at high energy, in R$$Xi$$ gauge using the MS-bar regularization scheme.