A grand unified SU(5) theory is constructed with a hierarchical breaking of a U(2) flavor symmetry. The small parameters of the squark and slepton mass matrices, necessary to solve the supersymmetric flavor-changing problem, and the inter-generational quark and lepton mass hierarchies are both generated from the U(2) symmetry breaking parameters. The flavor interactions of the theory are tightl...

One challenge associated with the simulation of buried detonations involves the treatment of the multiphase flow phenomena related to the soil. At the moment when the soil “shatters” into a dense particulate cloud with detonation products escaping through the soil particles, the continuum model that assumes a single velocity shared by the blast gas and the soil at any given point no longer hold...

We describe the effective supergravity theory present below the scale of spontaneous gauge symmetry breaking due to an anomalous U(1), obtained by integrating out tree-level interactions of massive modes. A simple case is examined in some detail. We find that the effective theory can be expressed in the linear multiplet formulation, with some interesting consequences. Among them, the modified l...

Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of avor, and gauge uni cation. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension...

I review the physics prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking. This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, D...

Cosmological considerations imply that the Weinberg-Salam Higgs boson mass mH ) 9 GeV. If this bound were violated, the symmetry breaking phase transition would occur only after extreme supercooling, resulting in too high a ratio of entropy to baryon number. Submitted to Physical Review Letters * Work supported by the Department of Energy, Contract DE-AC03-76SF00515. On leave from Cornell Unive...

A suite of climate data sets andmultiple representations of atmosphericmoisture demand are used to calculate many estimates of the self-calibrated Palmer Drought Severity Index, a proxy for near-surface soil moisture, across California from 1901 to 2014 at high spatial resolution. Based on the ensemble of calculations, California drought conditions were record breaking in 2014, but probably not...

in order to investigate the environmental factors including temperature, moisture, and plant hormones on dormancy breaking of seeds of xanthium strumarium l. a number of experiments were conducted. x. strumarium seeds were dormant soon after being harvested. seed germination of cocklebur increased through a combination of cooling, temperature fluctuations following ripening. most seed germinati...

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We ...