Collective treatment of High Energy Thresholds in SUSY - GUTs

Supersymmetric GUTs are the most natural extension of the Standard model unifying electroweak and strong forces. Despite their indubitable virtues, among these the gauge coupling unification and the quantization of the electric charge, one of their shortcomings is the large number of parameters used to describe the high energy thresholds (HET), which are hard to handle. We present a new method according to which the effects of the HET, in any GUT model, can be described by fewer parameters that are randomly produced from the original set of the parameters of the model. In this way, regions favoured by the experimental data are easier to locate, avoiding a detailed and time consuming exploration of the parameter space, which is multidimensional even in the most economic unifying schemes. To check the efficiency of this method, we directly apply it to a SUSY SO(10) GUT model in which the doublet-triplet splitting is realized through the Dimopoulos-Wilczek mechanism. We show that the demand of gauge coupling unification, in conjunction with precision data, locates regions of the parameter space in which values of the strong coupling \astrong are within the experimental limits, along with a suppressed nucleon decay, mediated by a higgsino driven dimension five operators, yielding lifetimes that are comfortably above the current experimental bounds. These regions open up for values of the SUSY breaking parameters m_0, M_1/2 < 1 TeV being therefore accessible to LHC.Comment: 21 pages, 8 figures, UA-NPPS/BSM-10/02 (added

Recent direct measurement of the Top quark mass and quasi-infrared fixed point

We note that the recent direct measurement of the top quark mass at $173.3 \pm 5.6 (stat) \pm 6.2 (syst)$ by D0 collaboration severely constrains the theoretically attractive infra-red fixed point scenario of the top quark Yukawa coupling in supersymmetric GUTs. For one-step unified models the above mentioned measurement bounds the arbitrary but experimentally determinable parameter $\tan \beta$ to the range $1.3 \le \tan \beta \le 2.1$. Further crunch on the top quark mass may determine $\tan \beta$ even more accurately within the fixed point scenario. On the other hand an experimental value of $\tan \beta > 2.1$ will rule out the fixed point scenario bounding $h^2_t(M_X)/4 \pi$ to 0.022 from above.Comment: 7 pages, Latex with epsf style, 1 figure, captions.st

Stock And Bond Price Dynamics-Evidence From An Emerging Economy

The motivation for this study is that real stock prices are observed to overreact to changes in interest rates. The real stock prices drop when long-term interest rates rise.  It has been observed that bonds and stock prices are typically studied in isolation. The present paper attempts to analyze the dynamic linkages between stock and bond prices in India.   One of the important contributions of this study is that in India, very little/almost no work has been done to understand the dynamics of the stock and bond prices after the recent recession. The present study examined the bivariate causal relationship between stock prices and bond prices.  In the long term; i.e., periods from 2004 to 2007 and 2008 to 2009, there is no causality from stock market to bond market and vice versa. However, it is found that the bond and stock prices had a bivariate causality in the year 2009 and univariate causality in 2010. The results are interesting and support the view that excess volatility causes granger between the stock and bond markets. This can be inferred as a result of recession investors moving to bond markets and after the signs of recovery the investors might be returning to the stock markets.   It is also evident that short-term interest rates have power to forecast short-term stock returns and risk premiums on observation of co-movement between stock and bond prices. This is reiterated by many empirical studies that have shown that the term “structure of nominal interest rates” contains information potentially useful for the conduct of monetary policy

Natural Gauge Hierarchy in SO(10)

It is shown that a natural gauge hierarchy and doublet-triplet splitting can be achieved in SO(10) using the Dimopoulos-Wilczek mechanism. Artificial cancellations (fine-tuning) and arbitrary forms of the superpotential are avoided, the superpotential being the most general compatible with a symmetry. It is shown by example that the Dimopoulos-Wilczek mechanism can be protected against the effects of higher-dimension operators possibly induced by Planck-scale physics. Natural implementation of the mechanism leads to an automatic Peccei-Quinn symmetry. The same local symmetries that would protect the gauge hierarchy against Planck-scale effects tend to protect the axion also. It is shown how realistic quark and lepton masses might arise in this framework. It is also argued that ``weak suppression'' of proton decay can be implemented more economically than can ``strong suppression'', offering some grounds to hope (in the context of SO(10)) that proton decay could be seen at Superkamiokande.Comment: 26 pages in plain LaTeX, 5 figures available on request, BA-94-0

Eliminating the d=5 proton decay operators from SUSY GUTs

A general analysis is made of the question whether the d=5 proton decay operators coming from exchange of colored Higgsinos can be completely eliminated in a natural way in supersymmetric grand unified models. It is shown that they can indeed be in SO(10) while at the same time naturally solving the doublet-triplet splitting problem, having only two light Higgs doublets, and using no more than a single adjoint Higgs field. Accomplishing all of this requires that the vacuum expectation value of the adjoint Higgs field be proportional to the generator I_{3R} rather than to B-L, as is usually assumed. It is shown that such models can give realistic quark and lepton masses. We also point out a new mechanism for solving the \mu problem in the context of SO(10) SUSY GUTs.Comment: 24 pages in LaTeX, with 3 figure

Characterization of nano-composite M-2411/Y-123 thin films by electron backscatter diffraction and in-field critical current measurements

Thin films of nano-composite Y-Ba-Cu-O (YBCO) superconductors containing nano-sized, non-superconducting particles of Y2Ba 4CuMOx (M-2411 with M = Ag and Nb) have been prepared by the PLD technique. Electron backscatter diffraction (EBSD) has been used to analyze the crystallographic orientation of nano-particles embedded in the film microstructure. The superconducting YBa2Cu3O7 (Y-123) phase matrix is textured with a dominant (001) orientation for all samples, whereas the M-2411 phase exhibits a random orientation. Angular critical current measurements at various temperature (T) and applied magnetic field (B) have been performed on thin films containing different concentration of the M-2411 second phase. An increase in critical current density J c at T < 77 K and B < 6 T is observed for samples with low concentration of the second phase (2 mol % M-2411). Films containing 5 mol % Ag-2411 exhibit lower Jc than pure Y-123 thin films at all fields and temperatures. Samples with 5 mol % Nb-2411 show higher Jc(B) than phase pure Y-123 thin films for T < 77 K

Introduction of medium deep sea trawler for commercial trawling at Sakthikulangara, Neendakara coast

A few entrepreneurs at Sakthikulangara launched three medium deep sea trawlers in September-October, 1988, aiming offshore resources like deep-sea prawns and lobsters and other quality fishes in the sea beyond 50 metres. Among these newly introduced vessels, two are wooden and the third is steel built. The specification of both type of vessels are tabled in this report. When compared to the existing trawlers they are much bigger in size, horse power, capacity and endurance, and well equipped in all respects

भारत में समुद्री अक्वापोनिक्स प्रणालियों की जीवन क्षमता

Viability of marine aquaponics systems in Indi

Nutritional evaluation of varying protein: energy ratios in feeds for Indian white shrimp Penaeus (Fenneropenaeus) indicus

Six experiments of six weeks duration were conducted in controlled conditions in the Indian white shrimp Fenneropenaeus indicus early juveniles (~0.040 mg initial weight). A common ingredient mixture (CIM) consisting of albumin (chicken egg), fish meal, shrimp meal, clam meal and deoiled ground nut oil cake was formulated and incorporated in all feeds at varying levels to obtain the requisite protein: energy combinations. Eight feeds tested in each experiment were formulated by incorporating CIM, cellulose (filler), tapioca flour (starch, binder), oil, mineral mixture, vitamin mixture and other additives viz., cholesterol and lecithin. The six protein levels fixed were 250 g kg-1 to 500 g kg-1 with 50 g kg-1 increments for each experiment. The gross energy (GE) levels in the eight dietary treatments for each level of protein varied from 290 kcal 100g-1 to 430 kcal 100g-1 and the digestible energy levels varied from198 – 300 kcal 100g-1. Growth, relative growth rate (RGR), absolute growth rate (AGR), food conversion efficiency (FCE), food conversion ratio (FCR), survival and initial and final body composition were monitored and analysed. One-way analysis of variance (ANOVA) followed by comparison of means was done to examine statistically significant differences between treatments and second degree polynomial regression of the from y = a + bx + cx2 was fitted with the data for RGR on P/E ratio (mg protein kcal-1), RGR on GE and RGR on DE to derive the optimum RGR, GE, DE and P/E. The results showed that growth of shrimp was highest with 450 g kg-1 protein and 363 kcal 100g- 1 GE, 276 kcal 100g-1 DE with a P/E of 124. Theoretical optima derived confirmed this observation with optimal values of 360 kcal 100g-1 GE, 275 kcal 100g-1 DE and a P/E ratio of 125. However, similar response in growth with feeds containing 350 - 450 g kg-1 protein indicating GE requirement of 362 – 371 kcal 100g-1 and DE requirement of 262 – 276 kcal100g-1 suggested a protein sufficiency of 350 g kg-1 with a P/E ratio of 98- 103 without major variations in the whole body composition

Constraining Proton Lifetime in SO(10) with Stabilized Doublet-Triplet Splitting

We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single adjoint, we show that the Dimopoulos--Wilzcek mechanism for DT splitting can be made stable in the presence of all higher order operators without having pseudo-Goldstone bosons and flat directions. The \mu term of order TeV is found to be naturally induced. A Z_2-assisted anomalous U(1)_A gauge symmetry plays a crucial role in achieving these results. The threshold corrections to alpha_3(M_Z), somewhat surprisingly, are found to be controlled by only a few effective parameters. This leads to a very predictive scenario for proton decay. As a novel feature, we find an interesting correlation between the d=6 (p\to e^+\pi^0) and d=5 (p\to \nu-bar K+) decay amplitudes which allows us to derive a constrained upper limit on the inverse rate of the e^+\pi^0 mode. Our results show that both modes should be observed with an improvement in the current sensitivity by about a factor of five to ten.Comment: 21 pages LaTeX, 2 figures, Few explanatory sentences and three new references added, minor typos corrected