Anomaly-Mediation and Sequestering from a Higher-Dimensional viewpoint

We study a five-dimensional supergravity model with boundary-localized visible sector exhibiting anomaly-mediated supersymmetry breaking, in which the central requirements of sequestering and radius stabilization are achieved perturbatively. This makes it possible to understand these various mechanisms in a more integrated and transparent fashion, mostly from the higher-dimensional viewpoint. Local supersymmetry, in the presence of visible sector quantum effects, is enforced by the formalism of the five-dimensional superconformal tensor calculus. The construction results in only mild warping, which allows a natural supersymmetry-breaking mediation mechanism of (finite) boundary-to-boundary gravity loops to co-dominate with anomaly-mediation, thereby solving the latter's tachyonic slepton problem. We make the non-trivial check that this can occur while dangerous loops of stabilizing fields remain highly suppressed. Our discussion is a well-controlled starting point for considering other generalizations of anomaly-mediation, or for string theory realizations.Comment: 33 pages, typos corrected, added references, version appearing in JHE

Asymptotic Symmetries, Holography and Topological Hair

Asymptotic symmetries of AdS$_4$ quantum gravity and gauge theory are derived by coupling the dual CFT$_3$ to Chern-Simons gauge theory and 3D gravity in a "probe" large-level limit. The infinite-dimensional symmetries are shown to arise when one is restricted to boundary subspaces with effectively two-dimensional geometry. A canonical example of such a restriction occurs within the 4D subregion described by a Wheeler-DeWitt wavefunctional of AdS$_4$ quantum gravity. An AdS$_4$ analog of Minkowski "super-rotation" asymptotic symmetry is probed by 3D Einstein gravity, yielding CFT$_2$ structure, via AdS$_3$ foliation of AdS$_4$ and the AdS$_3$/CFT$_2$ correspondence. The maximal asymptotic symmetry is however probed by 3D conformal gravity. Both 3D gravities have Chern-Simons formulation, manifesting their topological character. Chern-Simons structure is also shown to be emergent in the Poincare patch of AdS$_4$, as soft/boundary limits of 4D gauge theory, rather than "put in by hand", with a finite effective Chern-Simons level. Several of the considerations of asymptotic symmetry structure are found to be simpler for AdS$_4$ than for Mink$_4$, such as non-zero 4D particle masses, 4D non-perturbative "hard" effects, and consistency with unitarity. The last of these, in particular, is greatly simplified, because in some set-ups the time dimension is explicitly shared by each level of description: Lorentzian AdS$_4$, CFT$_3$ and CFT$_2$. The CFT$_2$ structure clarifies the sense in which the infinite asymptotic charges constitute a useful form of "hair" for black holes and other complex 4D states. An AdS$_4$ (holographic) "shadow" analog of Minkowski "memory" effects is derived. Lessons from AdS$_4$ provide hints for better understanding Minkowski asymptotic symmetries, the 3D structure of its soft limits, and Minkowski holography.Comment: typos corrected, references added, discussions of boundary conditions corrected and clarifie

Unfolding Particle Physics Hierarchies with Supersymmetry and Extra Dimensions

This is a written version of lectures delivered at TASI 2022 ``Ten Years After the Higgs Discovery: Particle Physics Now and Future''. Mechanisms and symmetries beyond the Standard Model (BSM) are presented capable of elegantly and robustly generating the striking hierarchies we observe in particle physics. They are shown to be among the central archetypes of quantum effective field theory and to strongly resonate with the tight structure and phenomenology of the Standard Model itself, allowing one to motivate, develop and test a worthy successor. The (Little) Hiearchy Problem is discussed within this context. The lectures culminate in specific BSM case-studies, gaugino-mediated (dynamical) supersymmetry breaking to generate the weak/Planck hierarchy, and (in less detail) extra-dimensional wavefunction overlaps to generate flavor hierarchies.Comment: 62 pages, 24 figures, TASI 2022 lectures, new references added in [3] and [20