Seminario
"Gauge Symmetry Breaking through Boundary conditions,
Can we live without the Higgs ?"
Relatore: Dott. Luigi Pilo Dip. di Fisica, Un. di Padova and INFN, Padova
Aula Einstein
16 Dicembre 2003 ore 15.30
Abstract

:We consider the breaking of gauge symmetry through boundary conditions
(BC's) extra dimensional gauge theories on an interval. To investigate
the nature of gauge
symmetry breaking via BC's we calculate the elastic scattering
amplitudes for longitudinal gauge bosons. We find that using a
consistent set of BC's the terms in these amplitudes that explicitly
grow with energy always cancel without having to introduce any
additional scalar degree of freedom, but rather by the exchange of
KaluzaKlein (KK) gauge bosons suggesting that perhaps the SM Higgs
could be completely eliminated. We show that from the lowenergy
effective theory
perspective this seems to be indeed possible. We present a 5D gauge
theory in warped
space based on a bulk $SU(2)_L otimes SU(2)_R otimes U(1)_{(BL)}$ gauge group where
the symmetry breaking pattern and the mass spectrum resembles that in
the standard
model (SM). To leading order in the warp factor the rho parameter and
the coupling of the Z (or equivalently the Sparameter) are as in the
SM, while corrections are expected at the level of a percent. This
model predicts the lightest W, Z and photon resonances to be at around
1.2 TeV, and no fundamental (or composite) Higgs particles.


