• Volume 8, Issue 4

      April 1977,   pages  303-395

    • Charged spin-1 gluons, parton model and the Archimedes effect

      V Elias Jogesh C Pati Abdus Salam J Strathdee

      More Details Abstract Fulltext PDF

      In a gauge theory of (SU(2)×U(1))flavour×SU(3)colour with un-confined integer-charged quarks and massive integer-charged gluons both quarks and gluons contribute to electro- and neutrino-production. The gluon parton contribution to the lepto-production of colour is considered.

    • Decays of the mesons and the singlet photon

      Jatinder K Bajaj M P Khanna

      More Details Abstract Fulltext PDF

      In an attempt to explain the recent measurements on the radiative decays of the vector-mesons (V), we study the consequences of introducing a small admixture of SU (3) singlet piece in the electromagnetic current. We find that this leads to an excellent fit of the theory with the new measurements on theV decays. However, this addition adversely affects the fit of the leptonic decays of the vector mesons (Ve+e) and of the radiative decay of the pion (π→2γ). We conclude that the overall fit to the available data does not favour a large (>10%) admixture of the SU(3) singlet. The decay rates have been calculated in the vectormeson dominance model. At the hadronic vertex (VVP), we assume asymptotic nonet symmetry. The electromagnetic couplings (Vγ) are the ones appropriate to vector-mixing.

    • Yields and energy spectra of light charged particles emitted in neutron induced fission of235U

      B Krishnarajulu G K Mehta R K Choudhury D M Nadkarni S S Kapoor

      More Details Abstract Fulltext PDF

      The yields and energy spectra of light charged particles emitted in the fission of235U have been measured in the neutron energy range of 100 keV to 1 MeV. The yield of long range alpha particles is found to increase around 200 keV neutron energy compared to thermal fission. A low energy component observed in the energy spectrum was assigned to the tritons emitted in fission. The yield of this triton component is seen to have a marked increase around 500 keV. These results indicate that LCP yield is influenced by the transition state level characteristics.

    • Prompt gamma ray multiplicity distributions in spontaneous fission of252Cf

      V S Ramamurthy R K Choudhury J O Mohankrishna

      More Details Abstract Fulltext PDF

      The shape parameters of the multiplicity distribution of prompt gamma rays emitted in spontaneous fission of252Cf were obtained using the multiple coincidence technique. The multiplicity distribution is well represented by a Gaussian distribution. Assuming the average number of prompt gamma rays emitted per fission to be 10.3, the standard deviation of the multiplicity distribution was estimated to be 4.2±0.4. The variation of the standard deviation of the multiplicity distribution has also been obtained as a function of kinetic energy of one of the fragments and was found to exhibit a strong zigzag dependence on the single fragment kinetic energy. The results have been discussed on the basis of the emission mechanism of prompt gamma rays in fission.

    • Density of states of the binary alloy in the coherent potential approximation

      A Prasanna Kumar

      More Details Abstract Fulltext PDF

      The density of states of an electron in a binary alloy in the tight binding model is calculated in the single site coherent potential approximation (CPA) as a function of the concentration and the site energy difference. The fluctuations in the site energies due to the random environment is taken into account approximately by giving width to the site energy probability distribution function, which is normally a sum of two delta functions with proper weight factor.

    • A. C. behaviour and dielectric relaxation in indium oxide films

      A Goswami Amit P Goswami

      More Details Abstract Fulltext PDF

      Vacuum deposited blackish indium oxide films (In-O) as well as the oxidised films (In2O3) were studied for their a.c. behaviour at different temperatures and at various film thicknesses in the audio frequency region. ε of In-O films was thickness dependent and also showed dielectric relaxation at lower frequencies due to the dipolar orientation arising from their non-stoichiometric nature. However at liquid nitrogen temperature region ε was thickness independent similar to the oxidised films which neither showed any relaxation effect nor any thickness dependent ε. The results have been discussed from the classical theory of dielectric polarisation.

    • Cuspidal edges for elastic wave surfaces for cubic crystals

      Jacob Philip K S Viswanathan

      More Details Abstract Fulltext PDF

      The paper deals with a detailed numerical study of the sections of the inverse and ray velocity surfaces for cubic crystals. The figures for the sections of the inverse and ray surfaces by the (001) and (110) planes have been plotted for over 65 crystals and from these, the nature of the cuspidal edges has been discussed. Typical graphs of the inverse and ray surfaces have been given. The parameters characterising the dimensions of the cusps have been tabulated. It is shown that the A-15 compounds exhibit very unusual and interesting wave surfaces at temperatures below superconducting critical temperatures.

    • Residue-squaring diagonalisation method and the anharmonic oscillator

      P M Mathews T R Govindarajan

      More Details Abstract Fulltext PDF

      A recently-formulated residue-squaring method for perturbation problems is subjected to an exacting test in its application to the problem of diagonalising the Hamiltonian of the nonlinear oscillator with quartic anharmonicity. Unlike other methods, this new iterative diagonalisation method enables several eigenvalues to be calculated simultaneously with little more labour than for a single eigenvalue. Values obtained for the four lowest even-parity levels of the anharmonic oscillator from just two or three iterations are shown to agree well with earlier accurate calculations. An approximate analytical formula for the energy levels is also presented.

    • Multiple penetrating particles with narrow separation associated with extensive air showers (EAS)

      B Chowdhuri Y C Saxena

      More Details Abstract Fulltext PDF

      An experiment has been carried out at a vertical depth of 580 m.w.e. at Kolar Gold Fields, to investigate various characteristics of energetic muons (Emln ⋍ 150 GeV) associated with extensive air showers (EAS). Double parallel penetrating particles with narrow separations (<1m) have an exponential decoherence distribution withe-folding separation of ⋍ 25 cm.

    • Detection and analysis of radio pulses from extensive air showers

      P C Barua S K Barthakur K M Pathak

      More Details Abstract Fulltext PDF

      Radio pulses from extensive air showers (EAS) at 30, 44, and 60 MHz frequencies have been studied, using wide band broad-side arrays of half-wave dipole antenna systems. The experimental results support the theoretical prediction that the field strength of radio emission depends on the shower size. An asymmetry has been noticed in the pulse height distributions of radio pulses detected by North-South and East-West directed arrays. These observations are in agreement with the theory that the charge separation mechanism is predominant in generating radio pulses from EAS and radio emission is polarised in the East-West direction. Experimental data are compared with those of earlier workers.

    • Radiation damping in an anharmonic oscillator

      K S Agarwal M B Banerjee Amar Nath Nigam

      More Details Abstract Fulltext PDF

      The effect of radiation damping in an anharmonic oscillator has been calculated using the technique of Kryloff and Bogolituboff. It is found that the intensity distribution of the emitted spectral line is asymmetric about its intensity maximum. The index of asymmetry agree with the experimental data on x-rayKa1,2lines.

    • Charged particle trajectories in a magnetic field on a curved space-time

      A R Prasanna R K Varma

      More Details Fulltext PDF
  • Pramana – Journal of Physics | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.