• S G Kamath

      Articles written in Pramana – Journal of Physics

    • A kinematical basis for power form factors

      S G Kamath M Gupta S Chakrabarty A N Mitra

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      A kinematical basis is proposed for form factors of the power type associated with multiple derivative couplings, on the basis of a Lorentz contraction effect on the external momenta involved in the transition matrix elements for mesons and baryons as appropriate quark composites. The argument (due to Licht and Pagnamenta) which applies separately to the Breit and c.m. frames for a decay matrix element provides a formal theoretical justification for thead hoc power form factors used by the Delhi group in a series of applications to hadronic processes over the past few years. The radius of interaction finds a natural place in this description simply from dimensional considerations, and its rather small magnitude, less than 0.5F, estimated fromfits to the data indicates a relatively small role played by structure effects. The Breit frame form factors, which work somewhat better than the c.m. frame ones (effectively used in the earlier studies), give a rather impressive sets of fits to the baryon decays in the (L + 1) wave (consistently for both vertical and horizontal) and the (L − 1) wave (mainly horizontal). The mesonic decays, the data for which are available mostly for the (L + 1) wave, are also fitted with an equal degree of consistency without any extra assumptions.

    • The superconformal anomaly in the 1 + 1 dimensional Wess-Zumino model

      S G Kamath

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      The superconformal trace anomaly is worked out to one-loop order in perturbation theory for the 1+1 dimensional Wess-Zumino model.

    • BRST invariance and the conical pendulum

      S G Kamath

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      The Hamiltonian formulation of the BRST method for quantizing constrained systems developed recently by Nemeschanskyet al is applied to the well-known problem of the conical pendulum in classical mechanics. The similarity of the system to a gauge theory wherein the two constraints serve as generators of local Abelian gauge transformations is also pointed out. The definition of the physical states of the system as a gauge theory and also as a BRST invariant theory is then discussed in some detail.

    • Whenħ meets G: An application of the HeunB function

      S G KAMATH

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      How does the inclusion of a gravitational potential alter an otherwise exact quantum mechanical result? This question motivates this report, with the answer determined from an edited version of a problem with a pair of masses sandwiched between three springs obeying Hooke’s law. To elaborate, we begin with the Hamiltonian associated with the vibration of the two masses about their equilibrium positions in one dimension; the Schrödinger equation for the reduced mass is then solved to obtain the parabolic cylinder functions (x) as eigenfunctions, and the eigenvalues of the reduced Hamiltonian are calculated exactly. The introduction of the gravitational potential in the Schrödinger equation alters the eigenfunctions (x) to the bi-confluent HeunB(q, α, γ , δ, ε, x) function;and the eigenvalues are then determined from a recent series expansion in terms of the Hermite functions for the solution of the differential equation whose exact solution is the aforesaid HeunB function.

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