FI: GENERALIZED HIGGS EFFECTIVE FIELD THEORY - RYO NAGAI
SEZIONE DI FIRENZE We formulate a generalization of Higgs effective field theory (HEFT)
including arbitrary number ofÂ
extra neutral and charged Higgs bosons (generalized HEFT, GHEFT) to
describe non-minimal electroweakÂ
symmetry breaking models. Using the geometrical form of the GHEFT
Lagrangian, which can be regardedÂ
as a nonlinear sigma model on a scalar manifold, it is shown that the
scalar boson scattering amplitudes areÂ
described in terms of the Riemann curvature tensor (geometry) of the
scalar manifold and the covariantÂ
derivatives of the potential. The one-loop divergences in the oblique
correction parameters S and U canÂ
also be written in terms of the Killing vectors (symmetry) and the Riemann
curvature tensor (geometry).Â
It is found that perturbative unitarity of the scattering amplitudes
involving the Higgs bosons and the longitudinalÂ
gauge bosons demands the flatness of the scalar manifold. The relationship
between the finiteness of theÂ
electroweak oblique corrections and perturbative unitarity of the
scattering amplitudes is also clarified inÂ
this language: we verify that once the tree-level unitarity is ensured,
then the one-loop finiteness of the obliqueÂ
correction parameters S and U is automatically guaranteed.
 This talk is based on arXiv:1904.07618. (Ryo Nagai - ICRR, U. of Tokyo)
DATA: 09-07-2019
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