Melting of shell effects and radiating dumbbells – two interesting problems in nuclear physics

ABSTRACT: 

I will discuss two problems [1, 2] in low energy nuclear physics as examples of interesting physics that can be explored at facilities such as the Pelletron Linac Facility at Mumbai. The first concerns the damping of the shell effect with temperature predicted by Ramamurthy et al. [PRL 25, 386 (1970)]. This was recently addressed experimentally by measuring neutron TOF spectra using the triton transfer-fusion reaction on 205Tl and 181Ta targets with a 7Li beam. The second example relates to electromagnetic signatures of the alpha cluster structure of 8Be. This nucleus, while being unstable in the ground state, lives long enough for subsequent capture by another alpha particle to form 12C through the Hoyle state at 7.65 MeV. A precise measurement of the rare electromagnetic transition (branch  107) from the 4+ resonance to the 2+ resonance in 8Be, which confronts ab initio calculations of light nuclei and the simpler cluster model, will be described. The need for a measurement of the much weaker and more challenging 2+-to-0+ transition, together with calculations that treat state-of-the-art structure models with reaction theory, will be emphasized.   

[1] P.C. Rout et al., Phys. Rev. Lett. 110, 062501 (2013)
[2] V. M. Datar et al., Phys. Rev. Lett. 111, 062502 (2013)