Recently, Berenstein et al. have proposed a duality between a sector of N = 4 super-Yang-Mills theory with large R-charge J, and string theory in a pp-wave background. In the limit considered, the effective 't Hooft coupling has been argued to be λWe study Yang-Mills theory at small λ ′ (large µ) with a view to reproducing string interactions. We demonstrate that the effective genus counting parameter of the Yang-Mills theory is g4 , the effective two-dimensional Newton constant for strings propagating on the pp-wave background. We identify g 2 √ λ ′ as the effective coupling between a wide class of excited string states on the pp-wave background. We compute the anomalous dimensions of BMN operators at first order in g 2 2 and λ ′ and interpret our result as the genus one mass renormalization of the corresponding string state. We postulate a relation between the three-string vertex function and the gauge theory three-point function and compare our proposal to string field theory. We utilize this proposal, together with quantum mechanical perturbation theory, to recompute the genus one energy shift of string states, and find precise agreement with our gauge theory computation.

The order g 2 radiative corrections to all 2-and 3-point correlators of the composite primary operators Tr X k are computed in N = 4 supersymmetric Yang-Mills theory with gauge group SU (N ). Corrections are found to vanish for all N . For k = 2 this is a consequence of known superconformal nonrenormalization theorems, and for general k the result confirms an N → ∞, fixed large g 2 N supergravity calculation and further conjectures in hep-th/9806074. A 3-point correlator involving N = 4 descendents of Tr X 2 is calculated, and its order g 2 contribution also vanishes, giving evidence for the absence of radiative corrections in correlators of descendent operators.

It is likely that the LHC will observe a color- and 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 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-boson-like properties. If the conformal sector is strongly coupled, this pseudodilaton 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 (i) cubic self-interactions and (ii) a potential enhancement of couplings to massless SM gauge bosons.

We obtain the bounds on arbitrary linear combinations of operators of dimension 6 in the Standard Model. We consider a set of 21 flavor and CP conserving operators. Each of our 21 operators is tightly constrained by the standard set of electroweak measurements. We perform a fit to all relevant precision electroweak data and include neutrino scattering experiments, atomic parity violation, W mass, LEP1, SLD, and LEP2 data. Our results provide an efficient way of obtaining bounds on weakly coupled extensions of the Standard Model. *

We construct an SU (6)/Sp(6) non-linear sigma model in which the Higgses arise as pseudoGoldstone bosons. There are two Higgs doublets whose masses have no one-loop quadratic sensitivity to the cutoff of the effective theory, which can be at around 10 TeV. The Higgs potential is generated by gauge and Yukawa interactions, and is distinctly different from that of the minimal supersymmetric standard model. At the TeV scale, the new bosonic degrees of freedom are a single neutral complex scalar and a second copy of SU (2) × U (1) gauge bosons. Additional vector-like pairs of colored fermions are also present.