Walter D. Goldberger

Distinguishing the Higgs boson from the dilaton at the Large Hadron Collider

It is likely that the LHC will observe a colorand charge-neutral scalar whose decays are consistent with those of the Standard Model (SM) Higgs boson. The Higgs interpretation of such a discovery is not the only possibility. For example, electroweak symmetry breaking (EWSB) could be triggered by a spontaneously broken, nearly conformal sector. The spectrum of states at the electroweak scale would then contain a narrow scalar resonance, the pseudo-Goldstone boson of conformal symmetry breaking, with Higgs-like properties. If the conformal sector is strongly coupled, this pseudo-dilaton may be the only new state accessible at high energy colliders. We discuss the prospects for distinguishing this mode from a minimal Higgs boson at the LHC and ILC. The main discriminants between the two scenarios are (1) cubic self-interactions and (2) a potential enhancement of couplings to massless SM gauge bosons. A particularly interesting situation arises when the scale f of conformal symmetry breaking is approximately the electroweak scale v ≃ 246 GeV. Although in this case the LHC may not be able to tell apart a pseudo-dilaton from the Higgs boson, the self-interactions differ in a way that depends only on the scaling dimension of certain operators in the conformal sector. This opens the possibility of using dilaton pair production at future colliders as a probe of EWSB induced by nearly conformal new physics.

Effective field theory of gravity for extended objects

Using effective field theory (EFT) methods we present a Lagrangian formalism which describes the dynamics of nonrelativistic extended objects coupled to gravity. The formalism is relevant to understanding the gravitational radiation power spectra emitted by binary star systems, an important class of candidate signals for gravitational wave observatories such as LIGO or VIRGO. The EFT allows for a clean separation of the three relevant scales:

AdS/CFT duality for non-relativistic field theory

{r}_{s}

Warped supersymmetric grand unification

, the size of the compact objects,

High energy field theory in truncated anti-de Sitter space.

r

Dissipative effects in the worldline approach to black hole dynamics

, the orbital radius, and

Standard model couplings and collider signatures of a light scalar

r/v

Asymptotics of d-dimensional Kaluza-Klein black holes: Beyond the Newtonian approximation

, the wavelength of the physical radiation (where the velocity

Radiation and the classical double copy for color charges

v

Superembedding Methods for 4d N=1 SCFTs

is the expansion parameter). In the EFT, radiation is systematically included in the