• B K Jain

Articles written in Pramana – Journal of Physics

• Foreword

• Nuclear physics at small distances

We report on the study of meson and resonance production in nuclear collisions near the threshold. Because of the large momentum transfer, these reactions occur at length scales less than the size of the hadrons. We explore whether they are best described in terms of the quark-gluon picture or the meson-exchange picture. Comparing our results with the available experimental data we conclude that the spin-averaged cross-sections are best described in meson-exchange picture. The description of the observed nucleon-nucleus and hyperon-nucleus spin-orbit potentials are found to be consistent with the quark-gluon exchange picture.

Final state interaction effects inpp→ pΛK+ andpd3Heη reactions are explored near threshold to study the sensitivity of the cross-sections to thepΛ potential and theηN scattering matrix. The final state scattering wave functions between Λ andp andη and3He are described rigorously. The Λ production is described by the exchange of one pion and aK-meson between two protons in the incident channel. Theη production is described by a two-step model, where in the first step a pion is produced. This pion then produces anη by interacting with another nucleon

• Resonances inη-light nucleus systems

We locate resonances inη-light nucleus elastic scattering using the time delay method. We solve few-body equations within the finite rank approximation in order to calculate the t-matrices and hence the time delay for theη-3He andη-4He systems. We find a resonance very close to the threshold inη-3He elastic scattering, at about 0.5 MeV above threshold with a width of ∼2 MeV. The calculations also hint at the presence of sub-threshold states in both the cases

• Role of near threshold resonances in intermediate energy nuclear physics

The presence of a resonance close to the threshold strongly effects the dynamics of the interacting particles at low energies. Production of 12C, the element for life, in 4He burning in Sun is a classic example of such a situation. In intermediate energy nuclear physics, this situation arises in the interactions of an 𝜂-meson with a nucleon and that of a $K^−$-meson with a proton at low energies, where both these systems have a resonance or a bound state near their thresholds, resulting in a strong attractive interaction. If putting these mesons in nuclear environment produces a strong attraction, it is possible that, in nature there may exist 𝜂- and $K^−$-nuclear bound states. Such a tantalizing possibility has led to experimental and theoretical programmes to search for them. These efforts have produced positive results. This paper gives a brief critical overview of these studies, emphasizing especially the efforts led by Bhabha Atomic Research Centre (BARC).

• # Pramana – Journal of Physics

Volume 96, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019