Yuhsin Tsai

Warped penguin diagrams

We present an analysis of the loop-induced magnetic dipole operator in the RandallSundrum model of a warped extra dimension with anarchic bulk fermions and an IR brane-localized Higgs. These operators are finite at one-loop order and we explicitly calculate the branching ratio for μ → eγ using the mixed position/momentum space formalism. The particular bound on the anarchic Yukawa and Kaluza-Klein (KK) scales can depend on the flavor structure of the anarchic matrices. It is possible for a generic model to either be ruled out or unaffected by these bounds without any fine tuning. We quantify how these models realize this surprising behavior. We also review tree-level lepton flavor bounds in these models and show that these are are in mild tension with the μ→ eγ bounds from typical models with a 3 TeV Kaluza-Klein scale. Further, we illuminate the nature of the one-loop finiteness of these diagrams and show how to accurately determine the degree of divergence of a five-dimensional loop diagram using both the five-dimensional and KK formalism. This power counting can be obfuscated in the four-dimensional Kaluza-Klein formalism and we explicitly point out subtleties that ensure that the two formalisms agree. Finally, we remark on the existence of a perturbative regime in which these one-loop results give the dominant contribution. ar X iv :1 00 4. 20 37 v3 [ he pph ] 5 J an 2 01 2

The Birds and the Bs in RS: The

A bstractWe calculate contributions to the photon and gluon magnetic dipole operators that mediate b → sγ and b → dγ transitions in the Randall-Sundrum model of a warped extra dimension with anarchic bulk fermions and a brane localized Higgs. Unlike the Standard Model, there are large contributions to the left-handed b quark decays, parameterized by the Wilson coefficient

b to s \gamma

C_7^{\prime }

penguin in a warped extra dimension

, due to the pattern of bulk fermion localization, and sizable contributions from the gluonic penguins,

Dynamical framework for KeV Dirac neutrino warm dark matter

C_8^{{\left( \prime \right)}}

Exotic quarks in Twin Higgs models

, through renormalization group mixing. Further, unlike the Randall-Sundrum result for μ → eγ, the unprimed Wilson coefficients receive non-negligible contributions from the misalignment of the bulk fermion spectrum with the Standard Model flavor sector. We compare the size of effects and the constraints imposed by the branching ratios Br(B → Xsγ) and 〈Br(B → Xdγ)〉 within the minimal and the custodial model. Within the custodial framework, we study the effect on a number of benchmark observables and find that Br(B → Xsμ+μ−) and the forward-backward asymmetry in B → K*μ+μ− remain close to their Standard Model predictions. On the other hand, there can be large enhancements of the time-dependent CP asymmetry in B → K*γ and the transverse asymmetry

Galactic center gamma-ray excess through a dark shower

A_T^{{(2)}}

Spontaneous R-symmetry Breaking with Multiple Pseudomoduli

.

Reconciling Large And Small-Scale Structure In Twin Higgs Models

If the source of the reported

Gamma-rays from dark showers with twin Higgs models

3.5