Volume 16, Issue 5
May 1981, pages 369-435
pp 369-373 May 1981 Molecular Physics
Molecular polarizabilities of some amino acids 1. Glycine and L-alanine
V P Gupta V D Gupta C Mehrotra
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.
pp 375-383 May 1981 General Relativity
A NUT-like electrovac spacetime
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.
pp 385-390 May 1981 Crystallography
Crystal structure of ethyl pyruvate-2-methyl-4-chloro-phenyl hydrazone
K Ravindra Acharya D S Sake Gowda
Ethyl pyruvate-2-methyl-4-chloro-phenylhydrazone, C_{12}H_{15}N_{2}O_{2}Cl, 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.
pp 391-402 May 1981 Nuclear And Particle Physics
Optical reaction cross-sections for light projectiles
A Chatterjee K H N Murthy S K Gupta
The optical reaction cross-sections forn, p,^{2}H,^{3}He,^{3}He and^{4}He 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.
pp 403-408 May 1981 Nuclear And Particle Physics
Mass extrapolation of quarks and leptons to higher generations
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 massm_{t} 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).
pp 409-416 May 1981 Nuclear And Particle Physics
Nontrivial quadratic gauge-fixing in Yang-Mills theories
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.
pp 417-423 May 1981 Nuclear And Particle Physics
Asymptotic chiral symmetry, meson masses and decay constants
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.
pp 425-435 May 1981 Nuclear And Particle Physics
A four quark-parton model analysis of recent high energy neutrino-nucleon scattering data
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 sin^{2}ϑ_{W} and other useful parameters are also determined for the various models.
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