The tension between gauge coupling unification, the Higgs boson mass, and a gauge-breaking origin of the supersymmetric mu-term

We investigate the possibility of generating the $\mu$-term in the MSSM by the condensation of a field that is a singlet under the SM gauge group but charged under an additional family-independent $U(1)_X$ gauge symmetry. We attempt to do so while preserving the gauge coupling unification of the MSSM. For this, we find that SM non-singlet exotics must be present in the spectrum. We also prove that the pure $U(1)_X$ anomalies can always be solved with rationally charged fields, but that a large number of SM singlets are often required. For $U(1)_X$ charges that are consistent with an embedding of the MSSM in SU(5) or SO(10), we show that the $U(1)_X$ charges of the MSSM states can always be expressed as a linear combination of abelian subgroups of $E_6$. However, the SM exotics do not appear to have a straightforward embedding into GUT multiplets. We conclude from this study that if this approach to the $\mu$-term is correct, as experiment can probe, it will necessarily complicate the standard picture of supersymmetric grand unification.Comment: 10 pages, no figure

Building effectiveness communication ratios (BECs): an integrated ‘life-cycle’ methodology for mitigating energy-use in buildings

Current building regulations are generally prescriptive in nature. It is widely accepted in Europe that this form of building regulation is stifling technological innovation and leading to inadequate energy efficiency in the building stock. This has increased the motivation to move design practices towards a more ‘performance-based’ model in order to mitigate inflated levels of energy-use consumed by the building stock. A performance based model assesses the interaction of all building elements and the resulting impact on holistic building energy-use. However, this is a nebulous task due to building energy-use being affected by a myriad of heterogeneous agents. Accordingly, it is imperative that appropriate methods, tools and technologies are employed for energy prediction, measurement and evaluation throughout the project’s life cycle. This research also considers that it is imperative that the data is universally accessible by all stakeholders. The use of a centrally based product model for exchange of building information is explored. This research describes the development and implementation of a new building energy-use performance assessment methodology. Termed the Building Effectiveness Communications ratios (BECs) methodology, this performance-based framework is capable of translating complex definitions of sustainability for energy efficiency and depicting universally understandable views at all stage of the Building Life Cycle (BLC) to the project’s stakeholders. The enabling yardsticks of building energy-use performance, termed Ir and Pr, provide continuous design and operations feedback in order to aid the building’s decision makers. Utilised effectively, the methodology is capable of delivering quality assurance throughout the BLC by providing project teams with quantitative measurement of energy efficiency. Armed with these superior enabling tools for project stakeholder communication, it is envisaged that project teams will be better placed to augment a knowledge base and generate more efficient additions to the building stock

Cosmic Archaeology with Gravitational Waves from Cosmic Strings

Cosmic strings are generic cosmological predictions of many extensions of the Standard Model of particle physics, such as a $U(1)^\prime$ symmetry breaking phase transition in the early universe or remnants of superstring theory. Unlike other topological defects, cosmic strings can reach a scaling regime that maintains a small fixed fraction of the total energy density of the universe from a very early epoch until today. If present, they will oscillate and generate gravitational waves with a frequency spectrum that imprints the dominant sources of total cosmic energy density throughout the history of the universe. We demonstrate that current and future gravitational wave detectors, such as LIGO and LISA, could be capable of measuring the frequency spectrum of gravitational waves from cosmic strings and discerning the energy composition of the universe at times well before primordial nucleosynthesis and the cosmic microwave background where standard cosmology has yet to be tested. This work establishes a benchmark case that gravitational waves may provide an unprecedented, powerful tool for probing the evolutionary history of the very early universe.Comment: 6 pages, 3 figure

The Narrow-band Ultraviolet Imaging Experiment for Wide-field Surveys (NUVIEWS)-I: Dust scattered continuum

We report on the first results of the Narrow-band Ultraviolet Imaging Experiment for Wide-field Surveys (NUVIEWS), a sounding rocket experiment designed to map the far-ultraviolet background in four narrow bands. This is the first imaging measurement of the UV background to cover a substantial fraction of the sky. The narrow band responses (145, 155, 161, and 174 nm, 7-10 nm wide) allow us to isolate background contributions from dust-scattered continuum, H2 fluorescence, and CIV 155 nm emission. In our first flight, we mapped one quarter of the sky with 5-10 arcminute imaging resolution. In this paper, we model the dominant contribution of the background, dust-scattered continuum. Our data base consists of a map of over 10,000 sq. degrees with 468 independent measurements in 6.25 by 6.25 sq. degree bins. Stars and instrumental stellar halos are removed from the data. We present a map of the continuum background obtained in the 174 nm telescope. We use a model that follows Witt, Friedman, and Sasseen (1997: WFS) to account for the inhomogeneous radiation field and multiple scattering effects in clouds. We find that the dust in the diffuse interstellar medium displays a moderate albedo (a=0.55+/-0.1) and highly forward scattering phase function parameter (g=0.75+/-0.1) over a large fraction of the sky, similar to dust in star forming regions. We also have discovered a significant variance from the model.Comment: 16 pages, 3 ps figures, submitted to Astrophysical Journal Letter

Higgs Boson Exempt No-Scale Supersymmetry and its Collider and Cosmology Implications

One of the most straightforward ways to address the flavor problem of low-energy supersymmetry is to arrange for the scalar soft terms to vanish simultaneously at a scale $M_{c}$ much larger than the electroweak scale. This occurs naturally in a number of scenarios, such as no-scale models, gaugino mediation, and several models with strong conformal dynamics. Unfortunately, the most basic version of this approach that incorporates gaugino mass unification and zero scalar masses at the grand unification scale is not compatible with collider and dark matter constraints. However, experimental constraints can be satisfied if we exempt the Higgs bosons from flowing to zero mass value at the high scale. We survey the theoretical constructions that allow this, and investigate the collider and dark matter consequences. A generic feature is that the sleptons are relatively light. Because of this, these models frequently give a significant contribution to the anomalous magnetic moment of the muon, and neutralino-slepton coannihilation can play an important role in obtaining an acceptable dark matter relic density. Furthermore, the light sleptons give rise to a large multiplicity of lepton events at colliders, including a potentially suggestive clean trilepton signal at the Tevatron, and a substantial four lepton signature at the LHC.Comment: 36 pages, 16 figure

Higgs Boson Decays to Neutralinos in Low-Scale Gauge Mediation

We study the decays of a standard model-like MSSM Higgs boson to pairs of neutralinos, each of which subsequently decays promptly to a photon and a gravitino. Such decays can arise in supersymmetric scenarios where supersymmetry breaking is mediated to us by gauge interactions with a relatively light gauge messenger sector (M_{mess} < 100 TeV). This process gives rise to a collider signal consisting of a pair of photons and missing energy. In the present work we investigate the bounds on this scenario within the minimal supersymmetric standard model from existing collider data. We also study the prospects for discovering the Higgs boson through this decay mode with upcoming data from the Tevatron and the LHC.Comment: 18 pages, 5 figures, added references and discussion of neutralino couplings, same as journal versio

Holomorphic selection rules, the origin of the mu term, and thermal inflation

When an abelian gauge theory with integer charges is spontaneously broken by the expectation value of a charge Q field, there remains a Z_Q discrete symmetry. In a supersymmetric theory, holomorphy adds additional constraints on the operators that can appear in the effective superpotential. As a result, operators with the same mass dimension but opposite sign charges can have very different coupling strengths. In the present work we characterize the operator hierarchies in the effective theory due to holomorphy, and show that there exist simple relationships between the size of an operator and its mass dimension and charge. Using such holomorphy-induced operator hierarchies, we construct a simple model with a naturally small supersymmetric mu term. This model also provides a concrete realization of late-time thermal inflation, which has the ability to solve the gravitino and moduli problems of weak-scale supersymmetry.Comment: 18 pages, 1 figur