Jing Shu

5D UED: Flat and Flavorless

Abstract5D UED is not automatically minimally flavor violating. This is due to flavor asymmetric counter-terms required on the branes. Additionally, there are likely to be higher dimensional operators which directly contribute to flavor observables. We document a mostly unsuccessful attempt at utilizing localization in a flat extra dimension to resolve these flavor constraints while maintaining KK-parity as a good quantum number. It is unsuccessful insofar as we seem to be forced to add brane operators in such a way as to precisely mimic the effects of a double throat warped extra dimension. In the course of our efforts, we encounter and present solutions to a problem common to many extra dimensional models in which fields are “doubly localized:” ultra-light modes. Under scrutiny, this issue seems tied to an intrinsic tension between maintaining Kaluza-Klein parity and resolving mass hierarchies via localization.

Two jets and missing ET signature to determine the spins of new particles

We consider the spin determination of new colored particles in the missing energy plus jets channel at the early stage of the discovery. We use a three site moose model to describe the low energy Lagrangian of all same spin partner (LHT or UED like) models and check the gauge invariance of the amplitude. For the benchmark production and decay channel pp → U(R)U(R) → uuBHBH, in contrast to those in supersymmetric models, there are spin correlations which affect the polar and azimuthal angle distributions of the quarks from the heavy partner U(R) decay. We show such effects would be visible in the ETmiss/Meff distribution and the reconstructed azimuthal angle correlation using MAOS reconstruction.

Maximally Symmetric Composite Higgs Models

Maximal symmetry is a novel tool for composite pseudo Goldstone boson Higgs models: it is a remnant of an enhanced global symmetry of the composite fermion sector involving a twisting with the Higgs field. Maximal symmetry has far-reaching consequences: it ensures that the Higgs potential is finite and fully calculable, and also minimizes the tuning. We present a detailed analysis of the maximally symmetric SO(5)/SO(4) model and comment on its observational consequences.

Dark Matter and Collider Physics in Split-UED

Kaluza‐Klein dark matter is an attractive weakly interacting massive particle in universal extra dimension model. In the recent extension “split‐UED,” annihilation of Kaluza‐Klein dark matter with a mass range 600–1000 GeV provides excellent fits to the recently observed excesses in cosmic electron and positron fluxes of Pamela, ATIC and Fermi‐LAT experiments. The cosmic gamma‐ray flux in the same process can be significant around 300 GeV, thus can be observed or constrained by the forthcoming Fermi‐LAT diffuse gamma‐ray data. The collider signal at the LHC is the resonance in the dijets channels and the large missing energy in the missing energy plus jets.