Observation of non-yrast states in ¹¹⁶Sn and measurement of polarisation asymmetry

The structural aspects of nuclei have been deduced, conventionally, by investigating high-spin phenomena observed by incorporating the so-called yrast bands. The yrast bands connect those states which lie in lowest energies for a particular spin value (I). Attempts can, however, be made to study the non-yrast states in order to unravel nuclear structure at relatively lower spin values. Different excitation energy levels at lower angular momentum of the non-yrast bands can be made by bombarding targets with lighter projectiles. Many questions, such as γ-softness, can be answered with more data available in such low energy regime. Sn (Z=50) isotope, being a spherical nucleus, has a rich low-lying collective structure originating from proton 2p-2h excitation across the proton Z=50 shell closure. Even though this nucleus was very extensively studied, little or no information is available for the non-yrast states. Hence, the in-beam γ-ray spectroscopy is used to extract information regarding the electromagnetic transition among the various low lying states of ¹¹⁶Sn