Theory-Motivated Benchmark Models and Superpartners at the Tevatron

Recently published benchmark models have contained rather heavy superpartners. To test the robustness of this result, several benchmark models have been constructed based on theoretically well-motivated approaches, particularly string-based ones. These include variations on anomaly and gauge-mediated models, as well as gravity mediation. The resulting spectra often have light gauginos that are produced in significant quantities at the Tevatron collider, or will be at a 500 GeV linear collider. The signatures also provide interesting challenges for the LHC. In addition, these models usually account for electroweak symmetry breaking with relatively less fine-tuning than previous benchmark models.Comment: 44 pages, 4 figures; some typos corrected. Revisions reflect published versio

Relic Neutralino Densities and Detection Rates with Nonuniversal Gaugino Masses

We extend previous analyses on the interplay between nonuniversalities in the gaugino mass sector and the thermal relic densities of LSP neutralinos, in particular to the case of moderate to large tan beta. We introduce a set of parameters that generalizes the standard unified scenario to cover the complete allowed parameter space in the gaugino mass sector. We discuss the physical significance of the cosmologically preferred degree of degeneracy between charginos and the LSP and study the effect this degree of degeneracy has on the prospects for direct detection of relic neutralinos in the next round of dark matter detection experiments. Lastly, we compare the fine tuning required to achieve a satisfactory relic density with the case of universal gaugino masses, as in minimal supergravity, and find it to be of a similar magnitude. The sensitivity of quantifiable measures of fine-tuning on such factors as the gluino mass and top and bottom masses is also examined.Comment: Uses RevTeX; 14 pages, 16 figure

CP Violation in Supersymmetric U(1)' Models

The supersymmetric CP problem is studied within superstring-motivated extensions of the MSSM with an additional U(1)' gauge symmetry broken at the TeV scale. This class of models offers an attractive solution to the mu problem of the MSSM, in which U(1)' gauge invariance forbids the bare mu term, but an effective mu parameter is generated by the vacuum expectation value of a Standard Model singlet S which has superpotential coupling of the form SH_uH_d to the electroweak Higgs doublets. The effective mu parameter is thus dynamically determined as a function of the soft supersymmetry breaking parameters, and can be complex if the soft parameters have nontrivial CP-violating phases. We examine the phenomenological constraints on the reparameterization invariant phase combinations within this framework, and find that the supersymmetric CP problem can be greatly alleviated in models in which the phase of the SU(2) gaugino mass parameter is aligned with the soft trilinear scalar mass parameter associated with the SH_uH_d coupling. We also study how the phases filter into the Higgs sector, and find that while the Higgs sector conserves CP at the renormalizable level to all orders of perturbation theory, CP violation can enter at the nonrenormalizable level at one-loop order. In the majority of the parameter space, the lightest Higgs boson remains essentially CP even but the heavier Higgs bosons can exhibit large CP-violating mixings, similar to the CP-violating MSSM with large mu parameter.Comment: 29 pp, 3 figs, 2 table

Frictionless Contact Between a Rigid Indentor and a Transversely Isotropic Functionally Graded Layer

This article is concerned with the study of frictionless contact between a rigid punch and a transversely isotropic functionally graded layer. The rigid punch is assumed to be axially symmetric and is supposed to be pressing the layer by an applied concentrated load. The layer is resting on a rigid base and is assumed to be sufficiently thick in comparison with the amount of indentation by the rigid punch. The graded layer is modeled as a non-homogeneous medium. The relationship between the applied load P and the contact area is obtained by solving the mathematically formulated problem through using the Hankel transform of different order. Numerical results have been presented to assess the effects of functional grading of the medium and the applied load on the stress distribution in the layer as well as on the relationship between the applied load and the area of contact

<span style="font-size:12.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-ansi-language: EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:AR-SA" lang="EN-IN">Andrographolide and other constituents of <i>Holmskioldia sanguinea</i></span>

632-634A new compound 27-methylnonaeicosanol <b style="mso-bidi-font-weight: normal">1 together with known lipids, triterpenoids, flavonoids, bioactive andrographolide and neoandrographolide have been isolated from Holmskioldia sanguinea and identified by their spectral and chemical study. This is the second natural occurrence of andrographolide and neoandrographolide, and their first occurrence from H. sanguinea is of chemotaxonomic importance

Block based image segmentation

Image segmentation is an important research field due increasing Internet and computer based applications and also for video coding but it is very challenging. There exist a huge number of algorithms for image segmentation using split and merge having some limitations for which pattern based object segmentation using split and merge (PSM) was proposed to overcome the problems of basic split and merge (SM) algorithm being unable to segment properly all types of objects in an image due to huge variations among the objects. Addressing this issue, a new algorithm namely block based image segmentation (BIS) algorithm has been presented in this paper considering multi stage merging technique. The experimental analysis proves the superior performance over the existing algorithm