The Weak Mixing Angle From TeV Scale Quark-Lepton Unification

Unified theories based on an extended left-right symmetric group, $SU(4) \times SU(2)^4$, are constructed in five dimensions. The compactification scale is assumed to be only a loop factor above the weak scale, so that the weak mixing angle is predicted to be close to its tree level value of 0.239. Boundary conditions in the 5th dimension break $SU(4) \to SU(3) \times U(1)_{B-L}$, removing powerful constraints from $K_L \to \mu e$ while allowing a reliable calculation of the leading logarithm corrections to $\sin^2 \theta$. The compactification scale is expected in the 1--5 TeV region, depending on how $SU(2)^4$ is broken. Two illustrative models are presented, and the experimental signal of the $Z'$ gauge boson is discussed.Comment: 15 page

Realistic Anomaly Mediation with Bulk Gauge Fields

We present a simple general framework for realistic models of supersymmetry breaking driven by anomaly mediation. We consider a 5-dimensional "brane universe" where the visible and hidden sectors are localized on different branes, and the standard model gauge bosons propagate in the bulk. In this framework there can be charged scalar messengers that have contact interactions with the hidden sector, either localized in the hidden sector or in the bulk. These scalars obtain soft masses that feed into visible sector scalar masses at two loop order via bulk gauge interactions. This contribution is automatically flavor-blind, and can be naturally positive. If the messengers are in the bulk this contribution is automatically the same order of magnitude as the anomaly mediated contribution, independent of the brane spacing. If the messengers are localized to a brane the two effects are of the same order for relatively small brane spacings. The gaugino masses and A terms are determined completely by anomaly mediation. In order for anomaly mediation to dominate over radion mediation the radion must be is stabilized in a manner that preserves supersymmetry, with supergravity effects included. We show that this occurs in simple models. We also show that the mu problem can be solved by the vacuum expectation value of a singlet in this framework.Comment: 16 pages, LaTeX2e, no figure

India and the Indo-Pacific an emerging regional vision

This report looks at India and the continuing change in political and trade influences in the Indo-Pacific region and the possible effects it will have on existing political powers such as the United States of America and Australia. The rapid expansion of trade, investment and production linkages in the area spanning the Indian and Pacific Oceans and the shift of economic power from the Trans-Atlantic to Asia has given rise to a push by commentators to have the ‘IndoPacific’ region recognised as a single geo-strategic arc. Yet, the concept remains politically contested and there has been insufficient attention paid to the geopolitical and geoeconomic drivers behind its emergence in particular national contexts. Among the most prominent promoters of the ‘Indo-Pacific’ have been commentators and state actors in the United States, Australia and India. This policy brief analyses the debate on the Indo-Pacific in India, in particular, and suggests that the adoption of the Indo-Pacific terminology by Indian officials is a reflection of the dominance of domestic economic imperatives in the making of contemporary Indian foreign policy. This is at variance with the driving motivation behind the promotion of the term by officials in the United States and Australia and suggests that the common adoption of the Indo-Pacific concept does not mean a convergence in foreign policy priorities

Symmetry Breaking Patterns for the Little Higgs from Strong Dynamics

We show how the symmetry breaking pattern of the simplest little Higgs model, and that of the smallest moose model that incorporates an approximate custodial SU(2), can be realized through the condensation of strongly coupled fermions. In each case a custodial SU(2) symmetry of the new strong dynamics limits the sizes of corrections to precision electroweak observables. In the case of the simplest little Higgs, there are no new light states beyond those present in the original model. However, our realization of the symmetry breaking pattern of the moose model predicts an additional scalar field with mass of order a TeV or higher that has exactly the same quantum numbers as the Standard Model Higgs and which decays primarily to third generation quarks.Comment: 5 pages, 3 figure

Radion Mediated Supersymmetry Breaking

We point out that in supersymmetric theories with extra dimensions, radius stabilization can give rise to a VEV for the $F$ component of the radius modulus. This gives an important contribution to supersymmetry breaking of fields that propagate in the bulk. A particularly attractive class of models is obtained if the standard-model gauge fields propagate in the bulk, while the quark and lepton fields are localized on a brane. This leads to gaugino mediated supersymmetry breaking without the need for singlets in the hidden sector. We analyze a simple explicit model in which this idea is realized

Effective Theory of a Light Dilaton

We consider scenarios where strong conformal dynamics constitutes the ultraviolet completion of the physics that drives electroweak symmetry breaking. We show that in theories where the operator responsible for the breaking of conformal symmetry is close to marginal at the breaking scale, the dilaton mass can naturally lie below the scale of the strong dynamics. However, in general this condition is not satisfied in the scenarios of interest for electroweak symmetry breaking, and so the presence of a light dilaton in these theories is associated with mild tuning. We construct the effective theory of the light dilaton in this framework, and determine the form of its couplings to Standard Model states. We show that corrections to the form of the dilaton interactions arising from conformal symmetry violating effects are suppressed by the square of the ratio of the dilaton mass to the strong coupling scale, and are under good theoretical control. These corrections are generally subleading, except in the case of dilaton couplings to marginal operators, when symmetry violating effects can sometimes dominate. We investigate the phenomenological implications of these results for models of technicolor, and for models of the Higgs as a pseudo-Nambu-Goldstone boson, that involve strong conformal dynamics in the ultraviolet.Comment: Version to appear in Phys. Rev.

Constraints on lepton flavor violation in the MSSM from the muon anomalous magnetic moment measurement

We establish a correspondence between those Feynman diagrams in the MSSM which give supersymmetric contributions to the muon anomalous magnetic moment and those which contribute to the flavor violating processes $\mu --> e\gamma$ and $\tau --> \mu\gamma$. Using current experimental limits on the branching ratios of these decay modes, combined with the assumption of a supersymmetric contribution to the muon anomalous magnetic moment, we establish bounds on the size of the lepton flavor violating soft masses in the MSSM largely independent of assumptions about other supersymmetric parameters. If the deviation measured at Brookhaven National Laboratory is from supersymmetry, we find the bounds {m^2}_{e \mu}/ {{\bar{m}}^2} \lsim 2 \times 10^{-4} and {m^2}_{\tau \mu}/ {{\bar{m}}^2} \lsim 1 \times 10^{-1}, where ${\bar{m}}^2$ is the mass of the heaviest particle in any loop that contributes at this level to the anomalous magnetic moment of the muon. This provides a significant constraint on the non-flavor-blind mediation of supersymmetry breaking that often occurs at a suppressed level in many models, including gaugino mediation.Comment: 25 pages, 6 figure