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Goldstone's theorem states that there is a massless mode for each broken symmetry generator. It has been known for a long time that the naive generalization of this counting fails to give the correct number of massless modes for spontaneously broken spacetime symmetries. We explain how to get the right count of massless modes in the general case, and(More)
We introduce a new brane-world model in which the bulk solution consists of outgoing plane waves. This is an exact solution to string theory with no naked singularities. The recently discussed self-tuning mechanism to cancel the cosmological constant on a brane is naturally incorporated. We show that even if the vacuum energy on the brane changes, e.g. due(More)
1550-7998=20 Spontaneous Lorentz violation due to a time-dependent expectation value for a massless scalar has been suggested as a method for dynamically generating dark energy. A natural candidate for the scalar is a Goldstone boson arising from the spontaneous breaking of a U 1 symmetry. We investigate the lowenergy effective action for such a Goldstone(More)
We rederive AdS/CFT predictions for infrared two-point functions by an entirely four dimensional approach, without reference to holography. This approach, originally due to Migdal in the context of QCD, utilizes an extrapolation from the ultraviolet to the infrared using a Padé approximation of the two-point function. We show that the Padé approximation and(More)
Following a strategy introduced earlier by the authors, we show that it is possible to extract |Vub| from the cut hadronic mass spectrum of B decays without large systematic errors which usually arise from having to model the Fermi motion of the heavy quark. We present a closed form expression for |Vub|/|Vts| which is accurate up to corrections of order α 2(More)
Marcela Carena, Howard E. Haber, Ian Low, Nausheen R. Shah, and Carlos E. M. Wagner Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510, USA Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA Santa Cruz Institute(More)
We derive constraints on the sign of couplings in an effective Higgs Lagrangian using prime principles such as the naturalness principle, global symmetries, and unitarity. Specifically, we study four dimension-six operators, OH , Oy, Og, and Oγ , which contribute to the production and decay of the Higgs boson at the Large Hadron Collider (LHC), among other(More)
We study the decay of a Z' boson into two Z bosons by extending the Landau-Yang theorem to a parent particle decaying into two Z bosons. For a spin-1 parent the theorem predicts that (1) there are only two possible couplings and (2) the normalized differential cross section depends on kinematics only through a phase shift in the azimuthal angle between the(More)