One Loop Soft Supersymmetry Breaking Terms in Superstring Effective Theories

We perform a systematic analysis of soft supersymmetry breaking terms at the one loop level in a large class of string effective field theories. This includes the so-called anomaly mediated contributions. We illustrate our results for several classes of orbifold models. In particular, we discuss a class of models where soft supersymmetry breaking terms are determined by quasi model independent anomaly mediated contributions, with possibly non-vanishing scalar masses at the one loop level. We show that the latter contribution depends on the detailed prescription of the regularization process which is assumed to represent the Planck scale physics of the underlying fundamental theory. The usual anomaly mediation case with vanishing scalar masses at one loop is not found to be generic. However gaugino masses and A-terms always vanish at tree level if supersymmetry breaking is moduli dominated with the moduli stabilized at self-dual points, whereas the vanishing of the B-term depends on the origin of the mu-term in the underlying theory. We also discuss the supersymmetric spectrum of O-I and O-II models, as well as a model of gaugino condensation. For reference, explicit spectra corresponding to a Higgs mass of 114 GeV are given. Finally, we address general strategies for distinguishing among these models.Comment: 49 pages: includes three tables and nine figure

On Quadratic Divergences in Supergravity, Vacuum Energy and the Supersymmetric Flavor Problem

We examine the phenomenological consequences of quadratically divergent contributions to the scalar potential in supergravity effective Lagrangians. We focus specifically on the effect of these corrections on the vacuum configuration of scalar fields in softly-broken supersymmetric theories and the role these corrections play in generating non-diagonal soft scalar masses. Both effects can only be properly studied when the divergences are regulated in a manifestly supersymmetric manner -- something which has thus far been neglected in past treatments. We show how a supersymmetric regularization can impact past conclusions about both types of phenomena and discuss what types of high-energy theories are likely to be safe from unwanted flavor-changing neutral current interactions in the context of supergravity theories derived from heterotic string compactifications

Life cycle assessment of Swiss organic farming systems

The impacts of organic and integrated farming systems in Switzerland on the environment have been assessed in a comprehensive study by the life cycle assessment method. This paper reports a comparison of the treatments of the DOC experiment. Organic farming showed clear ecological advantages particularly for eco- and human toxicity, resource use and biodiversity. These ecological advantages only partly apply to nutrient losses and are not always found for single products. Per kg of organic product, higher impacts were often found for global warming potential, ozone formation, eutrophication and acidification compared to integrated production. In the same crop rotation with the same amount of organic fertilisers there were no systematic differences in soil quality of organic compared with integrated production. Further improvement of the environmental performance of organic farming should focus on achieving higher yields of good quality – especially in potatoes and cereals - by using inputs more efficiently and minimising nitrogen losses

The Standard Model of Particle Physics

Particle physics has evolved a coherent model that characterizes forces and particles at the most elementary level. This Standard Model, built from many theoretical and experimental studies, is in excellent accord with almost all current data. However, there are many hints that it is but an approximation to a yet more fundamental theory. We trace the development of the Standard Model and indicate the reasons for believing that it is incomplete.Comment: 25 pages, 17 figures; accepted for publication in Rev. Mod. Physics (APS centenary issue

Understanding the Digital Divide As It Relates to Electronic Commerce

There exists an electronic digital divide within the United States. This digital divide concerns access to the Internet and its corresponding technologies. The U.S. government is concerned about the digital divide because it appears that certain ethnic groups and income levels are being excluded from computer technologies and the Internet. These groups include African Americans and Hispanics, who are lagging the Caucasians significantly in gaining access to the Internet. For a while the gap between majority and minority groups appeared to be widening. Since Internet access is a prerequisite to electronic commerce, an understanding of the relationship between the digital divide and marketing is important. Numerous Federal, State, and Local governments are trying to reduce or eliminate the digital divide to ensure equal access to all citizens. Marketing would benefit if equal access also meant increased electronic commerce. Business leaders are also concerned about the digital divide because it affects access to the Internet and corresponding technologies. If the consumers are denied access to the Internet, it will be difficult for them to participate in business to consumer (B2C) level electronic commerce. However, this research has shown statistically that solving the problems of the digital divide will not necessarily aid business to consumer level electronic commerce. The research has further found that the apparent reasons for the digital divide, currently thought to be income, education, and ethnic orientation, may be less important than initial government surveys indicate. The research demonstrates that between Internet access and consumer intent to purchase goods and services in business to consumer electronic commerce lies at least three other considerations that need to be addressed by business leaders. These areas are: consumer trust, consumer commitment, and consumer involvement with Internet technologies. All are important links between using the technology at all and using the technology for business to consumer electronic commerce. The research also shows that these three areas have a combined relationship to the magnitude of the digital divide. Thus, any actions that affect these constructs will also affect the digital divide. Business leaders seeking to engage in business to consumer electronic commerce must pay attention to consumer trust, consumer commitment, and optimizing the consumer experience (involvement) when using the Internet. Not addressing these issues proactively will increase the likelihood of failure while engaging in electronic commerce

The 2D analogue of the Reissner-Nordstrom solution

A two-dimensional (2D) dilaton gravity model, whose static solutions have the same features of the Reissner-Nordstrom solutions, is obtained from the dimensional reduction of a four-dimensional (4D) string effective action invariant under S-duality transformations. The black hole solutions of the 2D model and their relationship with those of the 4D theory are discussed.Comment: 5 pages, Plain-Tex, no figure

Constraints on Hidden Sector Gaugino Condensation

We study the phenomenology of a class of models describing modular invariant gaugino condensation in the hidden sector of a low-energy effective theory derived from the heterotic string. Placing simple demands on the resulting observable sector, such as a supersymmetry-breaking scale of approximately 1 TeV, a vacuum with properly broken electroweak symmetry, superpartner masses above current direct search limits, etc., results in significant restrictions on the possible configurations of the hidden sector.Comment: 33 pages, 10 figures. Full postscript also available from http://phyweb.lbl.gov/theorygroup/papers/44305.p

Testing Gaugino Mass Unification Directly at the LHC

We report on the first step of a systematic study of how gaugino mass unification can be probed at the LHC in a quasi-model independent manner. Here we focus our attention on the theoretically well-motivated mirage pattern of gaugino masses, a one-parameter family of models of which universal (high scale) gaugino masses are a limiting case. Using a statistical method to optimize our signature selection we arrive at three ensembles of observables targeted at the physics of the gaugino sector, allowing for a determination of this non-universality parameter without reconstructing individual mass eigenvalues or the soft supersymmetry-breaking gaugino masses themselves. In this controlled environment we find that approximately 80% of the supersymmetric parameter space would give rise to a model for which our method will detect non-universality in the gaugino mass sector at the 10% level with approximately 10 inverse femptobarns of integrated luminosity.Comment: To appear in proceedings of "Beyond the Standard Model at the LHC (BSM-LHC)", June 2-4, 200

Re-examination of Electroweak Symmetry Breaking in Supersymmetry and Implications for Light Superpartners

We examine arguments that could avoid light superpartners as an implication of supersymmetric radiative electroweak symmetry breaking. We argue that, from the point of view of string theory and standard approaches to generating the mu-term, cancellations among parameters are not a generic feature. While the coefficients relating the Z-mass to parameters in the soft supersymmetry breaking Lagrangian can be made smaller, these same mechanisms lead to lighter superpartner masses at the electroweak scale. Consequently we strengthen the implication that gluinos, neutralinos, and charginos are light and likely to be produced at the Fermilab Tevatron and a linear collider.Comment: 27 pages, 3 figure