Sudip Ghosh

Point-splitting analysis of commutator anomalies in non-abelian chiral gauge theories

A gauge covariant point-splitting regularisation is employed to calculate different anomalous commutators in four dimensional chiral gauge theories. For an external gauge field the fixed time anomalous commutator of the gauge group generators is seen to violate the Jacobi identity. The cohomological prediction can be confirmed provided the electric fields do not commute. Other commutators like the current-current and current-electric field are consistent with the Bjorken-Johnson-Low (BJL) derivation.

Excitation function measurement and reaction mechanism analysis for alpha-induced reactions on

Excitation functions have been measured for and produced by -particle-induced reactions on in the incident energy range 34-50 MeV. The excitation functions of these nuclei and those of , reported earlier, are analysed in terms of direct, pre-equilibrium and evaporation emissions. The two most commonly used models of pre-equilibrium reactions, the exciton and the hybrid models, have both been used and compared. The choice of the initial exciton number, the role of the pre-equilibrium cluster and multiple nucleon emissions have been investigated. The direct emission of clusters are found to significantly affect the excitation functions of and Au isotopes.

Pre-equilibrium cluster angular distribution in heavy ion nuclear reactions

A closed-form formulation is presented to evaluate pre-equilibrium cluster angular distribution in heavy ion reactions in terms of energy- and momentum-dependent level densities. The formalism is free of adjustable parameters and is tested for Z2 cluster emissions.

Closed-form evaluation of pre-equilibrium light-cluster emission in heavy ion reactions

Abstract A formalism is developed to evaluate pre-equilibrium cluster emission spectra in heavy ion reactions using a closed form expression obtained by extending the hybrid model of pre-equilibrium nuclear reactions.

Target-projectile symmetry effects on fast light-particle emissions in heavy ion reactions

Abstract A semi-classical formalism is presented to account for the change in shape of angular distributions of fast light ejectiles in heavy ion reactions with changing mass-symmetry of target and projectile.

Reaction mechanisms in {sup 16}O+{sup 40}Ca at an incident energy of E({sup 16}O) =86 MeV through inclusive measurements of {alpha} and proton spectra

The {alpha} and proton spectra from the {sup 16}O+{sup 40}Ca reaction is measured at E({sup 16}O) =86 MeV at several laboratory angles between 54 deg. and 138 deg. Analysis in terms of the statistical model for compound nuclear reactions show that an event-by-event calculation of the evaporation spectra removes discrepancy observed with standard calculations.

STUDY OF STATISTICAL EMISSIONS IN 28Si+natSi AND 28Si+27Al REACTIONS AT 4–5 MeV/A INCIDENT ENERGIES

We measure the energy spectra of α-particles and protons in 28Si+natSi and 28Si+27Al reactions at 4–5 MeV/A for both forward and backward angles. We show with a statistical model that the choice of the level density parameter plays a very crucial role in explainning the evaporation spectra. The shell corrected Gilbert Cameron level density parameter is found to give satisfactory results.

The relative stability of superheavy elements

The relative stability of superheavy elements against beta-decay and spontaneous fission has been investigated. A simple criterion of beta-stability using the Fermi gas model has been developed, tested in the range of stable nuclei and extended to the superheavy region. Spontaneous fission half-lives have been calculated using the statistical model in the expected region of relative beta-stability for superheavy nuclei. Our results have been compared with previous calculations.