Nuclear collective excitations in hot and fast rotating nuclei

One of the fascinating and extensively studied subjects in modern nuclear structure physics is the observation of giant dipole resonance (GDR) mode, which demonstrates a simple and well organized collective motion in complex many-body system like atomic nuclei. The phenomenon of GDR is very common one and it occurs in all nuclei. In liquid drop picture the resonance can be viewed as highly damped, small amplitude, high frequency, out of phase vibration of neutron and proton fluids in a spatial dipole pattern. The resonance is called 'giant' due to its large width in comparison to other known nuclear resonances and also due to the large cross section, implying that nearly all the nucleons participate in the vibration. The width of the resonance is related to the various damping mechanisms of the collective motion inside nuclear matter. The short lifetime of this resonance makes it an excellent probe to study the nuclear properties at extreme conditions, e.g. nuclear shapes and deformations at high temperature and angular momentum, fission time scale, isospin mixing, the ratio of nuclear shear viscosity to entropy volume density etc. In this study, an overview of T and J dependence of GDR parameters and recent research activities at VECC in this direction along with new experimental results will be presented