• Volume 24, Issue 3

      March 1985,   pages  423-544

    • Decays ofW andZ in the broken-colour model

      S Lakshmibala G Rajasekaran S D Rindani

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      The two-gluonic decay modes ofW andZ in the broken colour model with integrally charged quarks are considered. The gluonic branching ratios are found to be 3% and 2·7% forW andZ respectively. The angular distributions of the decays ofW andZ to two jets of hadrons are also worked out.

    • Pion-proton elastic scattering at 200 GeV/c

      Mohammad Saleem Fazal-E-Aleem

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      Recent measurements of differential and elastic cross-sections, slope parameters and ratios of the real and imaginary parts of the forward scattering amplitudes for pion-proton elastic scattering at 200 GeV/c have been fitted by using a simple Regge pole model with phenomenological residue functions. The computed results for total cross-sections have also been compared with the experimental data.

    • Fields with vanishing colour-currents

      G Rajasekaran V Srinivasan M S Sri Ram

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      We consider spinor, scalar and vector fields with colour degrees of freedom and find the classical solutions when the constraint of vanishing colour currents is imposed. We find that there are no non-trivialc-number solutions for spinor fields transforming as a triplet under SU(3), although solutions exist for scalar and vector fields. We also show that the colour current of spinor fields coupled to an instanton is zero.

    • Change of confinement scale in nuclei and the EMC effect

      Sourendu Gupta

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      We study a model in which the confinement scale of quarks in a nucleus of massA changes asA1/3. This explains theA dependence of structure functions (emc effect) as seen in muon, electron and antineutrino deep inelastic scattering from nuclear targets. We also investigate a prediction of this model—anA dependence of theqcd scale parameter A.

    • On the classical solution of SO(3) gauge theory and ’t Hooft-Polyakov monopole

      R Parthasarathy T S Santhanam K H Mariwalla

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      It is shown that the ansatz for the asymptotic (r → ∞) gauge fields used by ’t Hooft in the study of monopoles in SO(3) electroweak theory is not unique.

    • Low-lying vibrational states of145,147,149Nd

      Ramen Majumdar

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      The fragmented neutron states in145,147,149Nd detected through144Nd(d, p) and148,150Nd(d, t) reactions can be accounted for in terms of quasiparticles coupled with anharmonic vibrator model. The wave functions, obtained from diagonalisation of the Hamiltonian matrices are utilised to calculate B(E2), B(M1) and branching ratios in145,147Nd. The calculated results are discussed in the light of the recent experimental findings.

    • Annealing of54132Xe-ion tracks in Lexan and Makrofol plastic track detectors

      S M Farid

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      Samples of Lexan and Makrofol-E polycarbonate plastic track detectors were exposed to 1·1 MeV/N54132Xe-ions to investigate the thermal track fading properties of these plastics. The experimental results show that there is no effect of annealing on the bulk etch rate while the track etch rate decreases with annealing. The track diameter decreases with increase in annealing time and temperature. It is also observed that the track density is reduced as a result of annealing. The experiments reveal that the track lengths are, in general, decreased by the application of heat and that the oblique tracks are less stable than the vertical tracks. The decrease in diameter of54132Xe-ion tracks in Makrofol-E due to heat treatment is faster than that of54132Xe-ion tracks in Lexan.

    • Four component electromagnetic fields and electrodynamics

      M T Teli

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      Dirac-Maxwell equations with magnetic monopoles are generalized to electromagnetic fields by introducing fourth components to the fields and their solutions are obtained. The formalism is presented into tensor, dyonic as well as quaternionic forms and conservation theorems for the field energy and momenta are obtained involving the new contribution from the mutual interaction of the fields and currents. The generation of the standard modeste, tm andtem ofem waves is also obtained in the formalism.

    • Microwave spectrum ofcis 3-fluorophenol

      A Dutta A I Jaman

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      The microwave spectrum ofcis 3-fluorophenol involving rotational states up toJ=28 has been observed and analysed in the frequency range 23–25 GHz in the ground vibrational state at room temperature. Analysis yields three rotational and five quartic centrifugal distortion constants. A tentativer0 structure has been proposed satisfying the observed rotational constants. The small value of the inertia defect Δ=0·07 confirms the planarity of the conformer.

    • Rotational line strengths in4Σ-4Π transition of diatomic molecules

      T K Balasubramanian V P Bellary

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      A theoretical derivation of closed form expressions for the intensities of all the rotational branches arising out of4Σ-4Π electronic transition in a diatomic molecule is described. In the present theory the tradition of treating the coupling in the4Σ state as belonging to Hund’s case (b) is discarded; instead a full-fledged intermediate coupling treatment which rigorously takes into account the spin-spin and second order spin-orbit effects is presented. Since accurate intermediate coupling treatment of4Π, in analytically closed form, is not possible, the4Π is first restricted to the extreme coupling scheme Hund’s case (a)(or case (b)); the effect of spin uncoupling (or spin-orbit and spin-spin interactions) is then incorporated through a first order perturbation calculation.

    • The effect of soft modes on solitons in a linear lattice

      V Narasimha Iyer K S Viswanathan

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      Solitons are simulated in an anharmonic linear lattice that is susceptible to a soft mode instability. The soft mode characteristic is introduced in the system by the addition of a term (−Aun2) in the potential between the neighbouring atoms and the evolution of the system is studied as the soft mode parameterA varies from zero to the square of the limiting optical frequency. It is shown that the displacement pattern of the system shows three regions. First there is a region in which the relative displacements of the atoms show large amplitude oscillations. This is followed successively by a domain in which the relative displacements of the atoms are negligible and then by the soliton itself. In the soft mode region, the displacements of the atoms preceding the soliton decrease drastically in a linear fashion first, parabolically next and later become steady. It further exhibits a kind of devil’s stair cases.

    • Influence of magnetic field on the photorefractive effect in LiNbO3 crystals

      S K Arora G S Trivikrama Rao E M Uyukin

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      The photorefractive effect has been studied experimentally in single crystals of Fe and Mn-doped lithium niobate as a function of external static magnetic field. A strong dependence of changes in birefringence is observed on the magnitude and direction of the external field.

    • Effect of thermal pressure in converging detonation waves

      V P Singh

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      Propagation of converging detonation waves in various explosives is studied using the equation of state, which considers both the thermal and elastic pressures. It is seen that the rate of increase of thermal pressure is higher than that of the elastic pressure during convergence. The present equation of state is better since it also gives the variation of temperature, whereas the polytropic form of the equation of state is independent of temperature. It is seen that the total detonation pressure is slightly greater than the elastic pressure. Results are compared with those reported elsewhere.

    • A programmable digital pulse generator for pulsednmr spectroscopy

      R S Chaughule L C Gupta S M Telang

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      The pulse programmer generates highly stable pulses and is capable of producing various scheme of pulses (i.e. a given specific number of pulses with independently variable widths and separations) employed in pulsednmr spectroscopy. The construction and working of the programmer is described with reference to the two most commonly used schemes, namely, a two-pulse sequence and the Carr-Purcell sequence.

    • Erratum

      A S Divatia C Ambasankaran

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