We consider the possibility that the new particle that has been observed at
125 GeV is not the Standard Model (SM) Higgs, but instead the dilaton
associated with an approximate conformal symmetry that has been spontaneously
broken. We focus on dilatons that arise from theories of technicolor, or from
theories of the Higgs as a pseudo-Nambu-Goldstone boson (pNGB), that involve
strong conformal dynamics in the ultraviolet. In the pNGB case, we are
considering a framework where the Higgs particle is significantly heavier than
the dilaton and has therefore not yet been observed. In each of the technicolor
and pNGB scenarios, we study both the case when the SM fermions and gauge
bosons are elementary, and the case when they are composites of the strongly
interacting sector. Our analysis incorporates conformal symmetry violating
effects, which are necessarily present since the dilaton is not massless, and
is directly applicable to a broad class of models that stabilize the weak scale
and involve strong conformal dynamics. Since the AdS/CFT correspondence relates
the radion in Randall-Sundrum (RS) models to the dilaton, our results also
apply to RS models with the SM fields localized on the infrared brane, or in
the bulk. We identify the parameters that can be used to distinguish the
dilatons associated with the several different classes of theories being
considered from each other, and from the SM Higgs. We perform a fit to all the
available data from several experiments and highlight the key observations to
extract these parameters. We find that at present, both the technicolor and
pNGB dilaton scenarios provide a good fit to the data, comparable to the SM
Higgs. We indicate the future observations that will help to corroborate or
falsify each scenario.Comment: 41 pages, 4 figures. Analysis updated using current theoretical
limits on dimensions of CFT operators. References added. Version to appear on
JHE
