BARC/PUB/2021/0155

 
 

Effect of initial 3α cluster configurations in 12C on the direct decay of its Hoyle state

 
     
 
Author(s)

Baishya, A.; Santra, S.; Pal, A.; Rout, P. C.
(NPD)

Source

Physical Review-C, 2021. Vol. 104 (2): Article no. 24601

ABSTRACT

We investigate the implications of initial 3α configurations in 12C corresponding to different decay modes of its Hoyle state on the penetrability ratios. Considering the second 2+ (10.03 MeV) state to be a collective excitation of the Hoyle state, the  direct 3α decay width for the Hoyle state has been calculated using the ratio of the barrier penetration probability of the Hoyle state to the 2+ state. Semiclassical Wentzel–Kramers–Brillouin (WKB) approximation has been employed to determine the penetrability ratio, resulting in an upper limit on the branching ratio of the direct decay of the Hoyle state in  "equal phase-space" (DDφ) mode as Γ/Γ < 3.1 × 10−6. However, this limit for "linear chain" (DDL) decay is Γ3α/Γ < 2.6 × 10−7, which is one order of magnitude smaller than the DDφ decay and the limit for “equal energy” (DDE) decay is Γ/Γ < 1.5 × 10−5, which is greater than both DDφ and DDL decays. It implies that the limit on direct decay probability is strongly  dependent on the initial configuration of the 3α cluster. A further probe using a bent-arm-like 3α initial configuration shows that the direct decay probability is maximum when the angle of the bent arm is ≈ 120°, an important ingredient for understanding the Hoyle-state structure.

 
 
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