Experimental studies of clustering in light nuclei: 11,12,13,16C

Abstract

Different, complementary, techniques are used to experimentally probe clustering aspects in several carbon isotopes: $$^{11,12,13,16}$$C. Our approaches involve breakup reactions with radioactive cocktail beams ($$^{16}$$C), compound nucleus reactions and resonant scattering at low energies ($$^{11,13}$$C), and direct reactions with the detection of in-flight resonance decay fragments ($$^{12}$$C). In this paper, we discuss results of our experimental campaign: in $$^{11}$$C, we unveil the existence of a new excited state, characterized by clustering nature, at an excitation energy of 9.36 MeV ($$5/2^-$$); the decay path of the Hoyle state in $$^{12}$$C (7.654 MeV, $$0^+$$) is investigated with unprecedented precision; we refine the spectroscopy of $$^{13}$$C above the $$\alpha $$-threshold supporting the possible appearance of the $$K^\pi ={3/2}^\pm $$ molecular bands, based on the $$\alpha + ^{9}$$Be structure, previously discussed in the literature; in $$^{16}$$C, we find evidence for $$^{6}$$He–$$^{10}$$Be decays. Our findings have an impact on the understanding of clustering phenomena in light nuclear systems.