Figure 5.

Radiative decay partial width ${\mathrm{\Gamma }}_{\mathit{rad}}/{\mathrm{\Gamma }}_{\mathit{tot}}$ of the Hoyle state in $_{}^{12}$C from charged-particle coincidence experiments¹⁹ (Luo24)¹⁸, (Tsu21)¹⁵, (Mar76)¹⁴, (Mak75)¹³, (Dav75)¹², (Cha74)¹¹, (Hal64)¹⁰, (See63), and $\gamma$-particle coincidence experiments⁸ (Kib20)¹⁶, (Obs76)⁹, (Alb61). The result of²⁰ (${\mathrm{\Gamma }}_{2\gamma }/{\mathrm{\Gamma }}_{\mathit{tot}}=1.8\pm 0.6·{10}^{-3}$) is not shown for clarity reasons. The result of Ref. ¹⁹ is also affected by a systematic uncertainty of $\pm 0.16·{10}^{-4}$, not shown in the figure. The present estimate is also shown. The yellow band indicates the new confidence interval obtained through a weighted average of all available estimates, excluding the values from Refs.^8,10,20.