• Volume 16, Issue 5

      May 1981,   pages  369-435

    • Molecular polarizabilities of some amino acids 1. Glycine and L-alanine

      V P Gupta V D Gupta C Mehrotra

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      Atom-dipole interaction model has been used to calculate the molecular polarizabilities, refractive indices along the direction of principal polarizabilities of glycine and L-alanine and the molar optical rotation of L-alanine. The results of the calculation have been compared with experimentally observed data from Kerr effect and polarimetric measurements.

    • A NUT-like electrovac spacetime

      L K Patel S C Thaker

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      A solution of the Einstein-Maxwell equations corresponding to source-free electromagnetic field is obtained. The solution is algebraically special. A particular case of the solution is considered which includes Brill’s solution. The details regarding the solution are also discussed.

    • Crystal structure of ethyl pyruvate-2-methyl-4-chloro-phenyl hydrazone

      K Ravindra Acharya D S Sake Gowda

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      Ethyl pyruvate-2-methyl-4-chloro-phenylhydrazone, C12H15N2O2Cl, is an important intermediate for the synthesis of ethyl-5-chloro-7-methyl indole-2-carboxy-late. Crystals are orthorhombic witha=6.99(4),b=23.75(6),c=17.05(6) Å and eight molecules per cell in the space group Cmca. The structure was solved by direct methods using film data and refined by block diagonal least squares method to anR-index of 0.052. The molecule occupies the space group mirror(m) special position. The stacking of the molecules is stabilized by van der Waal’s contacts.

    • Optical reaction cross-sections for light projectiles

      A Chatterjee K H N Murthy S K Gupta

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      The optical reaction cross-sections forn, p,2H,3He,3He and4He for several global optical potentials available in the literature have been parametrized in terms of simple empirical expressions which are smooth functions of the target mass number and the projectile energy. The empirical forms are 5–10% accurate over the periodic table and energy-range upto 50 MeV. They can be conveniently used in calculations where the optical reaction cross-sections are required as input. The calculation of proton spectra in the (n, p) reaction at 14 MeV is discussed.

    • Mass extrapolation of quarks and leptons to higher generations

      N Barik

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      An empirical mass formula is tested for the basic fermion sequences of charged quarks and leptons. This relation is a generalization of Barut’s mass formula for the lepton sequence (e, μ, τ......). It is found that successful mass extrapolation to the third and possibly to other higher generations (N>2) can be obtained with the first and second generation masses as inputs, which predicts the top quark massmt to be around 20 GeV. This also leads to the mass ratios between members of two different sequences (i) and (i′) corresponding to the same higher generations (N>2).

    • Nontrivial quadratic gauge-fixing in Yang-Mills theories

      Ashok Das

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      We study renormalizability of a quadratic gauge-fixing choice involving gauge fields. We show that this can be renormalized simultaneously maintaining the BRS invariance since this respects the underlying global SU(n) invariance. However, this choice, too, induces quartic ghost terms in conformity with our earlier results.

    • Asymptotic chiral symmetry, meson masses and decay constants

      A Lahiri V P Gautam

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      Weinberg’s spectral function sum rules are examined to study the axial vector mass spectrum at the level of SU(4). New mass relations and general mass constraints are derived to predict the masses of the charmed axial vector mesons and theI=0 pseudoscalar decay constants.

    • A four quark-parton model analysis of recent high energy neutrino-nucleon scattering data

      S Hashim Rizvi Shoeb Abdullah

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      The data on neutrino (antineutrino), neutral and charged current cross-sections and theiry-distributions are analysed within the framework of the Weinberg-Salam theory and the quark-parton model incorporating charm. Other existing models are also compared. Interpretation of data appears easy in the case of models with charm whereas it is not so if charm is absent. Under some reasonable assumptions, the numerical values of the first moments of parton distribution functions are obtained. The sin2ϑW and other useful parameters are also determined for the various models.

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