Infrared Scales and Factorization in QCD

Effective field theory methods are used to study factorization of the deep inelastic scattering cross-section. The cross-section is shown to factor in QCD, even though it does not factor in perturbation theory for some choices of the infrared regulator. Messenger modes are not required in soft-collinear effective theory for deep inelastic scattering as x -> 1.Comment: 5 pages, 2 figures, revtex

Parental Selection for Productivity Improvement in Indian Tropical Tasar Silkworm, Antheraea mylitta Drury (Lepidoptera: Saturniidae)

Global demand for Vanya silks in general and tasar silk in particular, call-for sustainable utilization of the country’s seri-biodiversity potential. Viability and productivity proportion of tasarculture in terms of seeds, cocoons and essentially raw silk, need attention for its vital role in reforming the livelihood and economic condition of tribal farmers. The conventional approaches on basic stock maintenance, commercial seed production, selective use of parental races or parents for heterosis and heterobeltiosis, method of backcrossing to exploit the traits of commercial importance and applying the advantage of genotype x environment (G x E) interactions are indispensable. In spite of current knowledge on sophisticated transgenic silkworm, appropriate application of on-hand parental resource material and methodologies can expedite tasar silk productivity improvement in addition to up-keep of the agro based cottage industry’s cost-effectiveness

Supersymmetric Correction to Top Quark Pair Production near Threshold

We studied the leading supersymmetric contribution to top-antitop threshold production using the NRQCD framework. The one-loop matching to the potential and the Wilson coefficient of the leading production current were considered. We point out that the leading correction to the potential is zero due to SU(3)_c gauge invariance. This is true in general for any new physics that enters above the electroweak scale. The shape of the top quark pair production cross section is therefore almost unaffected near threshold, allowing a precise determination of the top quark mass based on the Standard Model calculations. The supersymmetric correction to the Wilson coefficient c_1 of the production current decouples for heavy super particles. Its contribution is smaller than the Standard Model next-to-next-leading-log results.Comment: 7 pages, 2 figure

Deep inelastic scattering as x -> 1 using soft-collinear effective theory

Soft-collinear effective theory (SCET) is used to sum Sudakov double-logarithms in the x ->1 endpoint region for the deep inelastic scattering structure function. The calculations are done in both the target rest frame and the Breit frame. The separation of scales in the effective theory implies that the anomalous dimension of the SCET current is linear in ln mu, and the anomalous dimension for the Nth moment of the structure function is linear in ln N, to all orders in perturbation theory. The SCET formulation is shown to be free of Landau pole singularities. Some important differences between the deep inelastic structure function and the shape function in B decay are discussed.Comment: 19 pages, minor typos fixed, and a comment added on the longitudinal structure functio

Avoidance of Singularity and Global Non-Conservation of Energy in General Relativity

We show that the singularity in the General Theory of Relativity (GTR) is the expression of a non-Machian feature. It can be avoided with a scale-invariant dynamical theory, a property lacking in GTR. It is further argued that the global non-conservation of energy in GTR also results from the lack of scale-invariance and the field formulation presented by several authors can only resolve the problem in part. Assuming the global energy conservation, we propose a negative energy density component with positive equation of state that can drive the late-time acceleration in the universe, while the positive component confines to smaller scales.Comment: 10 pages, no figure

Chiral Perturbation Theory

The basic ideas and power counting rules of chiral perturbation theory are discussed. The formalism of velocity dependent fields for baryons, and for hadrons containing a heavy quark, is explained. (Invited Talk, 1993 QCD Rencontres de Moriond)Comment: (uses harvmac, 9 pages, 1 figure), UCSD/PTH 93-1