Axion-Assisted Electroweak Baryogenesis

We consider a hidden-valley gauge sector, G, with strong coupling scale Lambda~TeV and CP-violating topological parameter, theta, as well as a new axion degree of freedom which adjusts theta to near zero in the current universe. If the G-sector couples to the Standard Model via weak-scale states charged under both, then in the early universe it is possible for the CP-violation due to theta (which has not yet been adjusted to zero by the hidden axion) to feed in to the SM and drive efficient baryogenesis during the electroweak (EW) phase transition, independent of the effectively small amount of CP violation present in the SM itself. While current constraints on both the new axion and charged states are easily satisfied, we argue that the LHC can investigate the vast majority of parameter space where EW-baryogenesis is efficiently assisted, while the hidden axion should comprise a significant fraction of the dark matter density. In the supersymmetric version, the ``messenger'' matter communicating between the SM- and G-sectors naturally solves the little hierarchy problem of the MSSM. The connection of the hidden scale and masses of the ``quirk''-like messengers to the EW scale via the assisted electroweak baryogenesis mechanism provides a reason for such new hidden valley physics to lie at the weak scale.Comment: 22+1 pages, 3 figure

The Goldstini Variations

We study the 'goldstini' scenario of Cheung, Nomura, and Thaler, in which multiple independent supersymmetry (SUSY) breaking sectors lead to multiple would-be goldstinos, changing collider and cosmological phenomenology. In supergravity, potentially large corrections to the previous prediction of twice the gravitino mass for goldstini masses can arise when their scalar partners are stabilized far from the origin. Considerations arising from the complexity of realistic string compactifications indicate that many of the independent SUSY-breaking sectors should be conformally sequestered or situated in warped Randall-Sundrum-like throats, further changing the predicted goldstini masses. If the sequestered hidden sector is a metastable SUSY-breaking sector of the Intriligator-Seiberg-Shih (ISS) type then multiple goldstini can originate from within a single sector, along with many supplementary 'modulini', all with masses of order twice the gravitino mass. These fields can couple to the Supersymmetric Standard Model (SSM) via the 'Goldstino Portal'. Collider signatures involving SSM sparticle decays can provide strong evidence for warped-or-conformally-sequestered sectors, and of the ISS mechanism of SUSY breaking. Along with axions and photini, the Goldstino Portal gives another potential window to the hidden sectors of string theory.Comment: 30 pages, 3 figures; v2 minor changes, references adde

From Serra to Sancho: Music and Pageantry in the California Missions

The topic of conversation is Craig Russell\u27s book From Serra to Sancho: Music and Pageantry in the California Missions, published in 2009 by Oxford University Press. Craig is joined in conversation by Dan Krieger, professor emeritus and local historian.https://digitalcommons.calpoly.edu/convocpauth/1005/thumbnail.jp

Serra and Sacred Song at the Founding of California\u27s First Missions

No Abstract

Efficient holographic proofs

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1996.Includes bibliographical references (p. 57-63).by Alexander Craig Russell.Ph.D

Residual stress measurement and structural integrity evaluation of SLM Ti-6Al-4V

Includes bibliographical references.The constant drive toward cleaner, more powerful and more efficient jet turbines in the aerospace industry has narrowed the gap between the aircraft performance envelope requirements and the material limits. The most advanced turbine engines are incredibly complex in design and the weight-saving requirements have placed significant pressure on material capabilities and the manufacturing systems. The next generation of manufacturing methodologies are being developed in the Additive Manufacturing (AM) arena from which Selective Laser Melting (SLM) has emerged as a promising candidate for producing highly complex components. Selective Laser Melting is a laser-based AM technique which builds 3-dimensionsal parts from CAD models in a layerwise fashion..

Selected technology options for sanitation provision to developing communities in urban South Africa

Includes bibliography.In 1990 the Water. Research Commission initiated an evaluation of sanitation entitled "Technical, socio-economic and environmental evaluation of sanitation systems for developing urban areas in South Africa". The research project was undertaken jointly by Palmer Development Group and the University of Cape Town. The project culminated in 26 reports submitted under the collective title "Urban Sanitation Evaluation" in December 1992. This thesis is based principally on the research work that the Water Research Group, Department of Civil Engineering, University of Cape Town, contributed to the project and, in particular, the overview document entitled " Technology options for sanitation provision to developing Communities" (PDG/UCT Document AS, 1992). Since 1986, after the removal of legal restrictions on urbanisation, a high rate of population movement to the cities and towns commenced with housing of the urban poor a focal point. The three essential aspects of housing are location in reasonable proximity to work, provision of services, in particular water supply and sanitation, and the house or shelter. Water supply and sanitation are basic health requirements. This thesis investigates selected technology options for sanitation provision to developing communities in urban South Africa