• A KUMAR

Articles written in Pramana – Journal of Physics

• Search for the effect of pressure on liquid-liquid critical phenomena

The coexistence curve of methanol + cyclohexane has been reanalyzed using an intrinsically simpler equation to study the influence of pressure on its asymmetry. The results confirm that no pressure dependence is discernible in the coexistence curve. Suggestions for future work in this direction are made.

• Photoionization of the ground1Se and twenty lowest excited states of the Ne-like Fe16+

TheR-matrix method is used to calculate cross-sections for the photoionization of Ne-like Fe16+ from ground 2s22p61Se and excited states belonging to 2s2p6 3l and 2s22p5 3l configurations. Configuration interaction wavefunctions are used to represent two target states of Fe17+ ion retained in theR-matrix expansion. The cross-sections are obtained as a function of kinetic energy (εk) of the ejected electron from 10 to 24 Ry. For low kinetic energy the cross-sections show series of Rydberg states which converge onto2Se threshold Fe17+. The calculations are carried out in the LS coupling.

• Depopulation of Na(8s) colliding with ground state He: Study of collision dynamics

A systematic study of the collison dynamics associated with depopulation of Na(8s) atom colliding with ground state He has been made by applying the semi-classical impact parameter method using molecular orbital (MO) basis sets of different sizes. The cross-sections for total depopulation of the parent atom as well as those for individual transitions have been calculated. It is shown that the basis set must be large enough so as to include not only the immediate adjacent states coupling with the parent state but also other nearby states, which can affect the overall flux distribution in the reaction.

• On the water-induced critical double point in a polymer solution: the role of isotopic substitution

This paper examines the effect of substitution of water by heavy water in a polymer solution of polystyrene (molecular weight=13000) and acetone. A critical double point (CDP), at which the upper and the lower partially-miscible regions merge, occurs at nearly the same coordinates as for the system [polystyrene+acetone+water]. The shape of the critical line for [polystyrene+acetone+heavy water] is highly asymmetric. An explanation for the occurrence of the water-induced CDP in [polystyrene+acetone] is advanced in terms of the interplay between contact energy dissimilarity and free-volume disparity of the polymer and the solvent. The question of the possible existence of a one-phasehole in an hourglass phase diagram is addressed in [polystyrene+acetone+water]. Our data exclude such a possibility.

• Physics potential of the ICAL detector at the India-based Neutrino Observatory (INO)

The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies andpath lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial toaddress some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations.We describe the simulation framework, the neutrino interactions in the detector, and the expected responseof the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Itscharge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles.

• $K^{0}_{S}$ Production from beryllium target using 120 GeV/c protons beam interactions at the MIPP experiment

We have measured the cross-section for the $K^{0}_{S}$ production from beryllium target using 120 GeV/c protons beam interactions at the main injector particle production (MIPP) experiment at Fermilab. The data were collected with target having a thickness of 0.94% of the nuclear interaction length. The $K^{0}_{S}$ inclusive differential cross-section in bins of momenta is presented covering momentum range from 0.4GeV/c to 30GeV/c. The measured inclusive $K^{0}_{S}$ production cross-section amounts to $39.54 \pm 1.46\delta_{stat} \pm 6.97\delta_{syst}$ mb and the value is compared with the prediction of FLUKA hadron production model.

• # Pramana – Journal of Physics

Current Issue
Volume 92 | Issue 6
June 2019