Diverse mechanisms in proton knockout reactions from the Borromean nucleus $$^{17}\text {Ne}$$

Abstract

AbstractNucleon knockout experiments using beryllium or carbon targets reveal a strong dependence of the quenching factors, i.e., the ratio ($$\hbox {R}_{\textrm{s}}$$ R s ) of theoretical to the experimental spectroscopic factors ($$\hbox {C}^2{\textrm{S}}$$ C 2 S ), on the proton-neutron asymmetry in the nucleus under study. However, this dependence is greatly reduced when a hydrogen target is used. To understand this phenomenon, exclusive $$^{1}\text {H}(^{17}\text {Ne},$$ 1 H ( 17 Ne , $$2\hbox {p}~^{16}\text {F})$$ 2 p 16 F ) and inclusive $$^{12}\text {C}(^{17}\text {Ne},2\hbox {p}~^{16}\text {F})\hbox {X}$$ 12 C ( 17 Ne , 2 p 16 F ) X , $$^{12}\text {C}(^{17}\text {Ne},$$ 12 C ( 17 Ne , $$^{16}\text {F})\hbox {X}$$ 16 F ) X as well as $$^{1}\text {H}(^{17}\text {Ne},^{16}\text {F})\hbox {X}$$ 1 H ( 17 Ne , 16 F ) X (X-denotes undetected reaction products) reactions with $$^{16}\text {F}$$ 16 F in the ground and excited states were analysed. The longitudinal momentum distribution of $$^{16}{\textrm{F}}$$ 16 F and the correlations between the detached protons were studied. In the case of the carbon target, there is a significant deviation from the predictions of the eikonal model. The eikonal approximation was used to extract spectroscopic factor values $$\hbox {C}^2{\textrm{S}}$$ C 2 S . The experimental $$\hbox {C}^2\hbox {S}$$ C 2 S value obtained with C target is markedly lower than that for H target. This is interpreted as rescattering due to simultaneous nucleon knockout from both reaction partners, $$^{17}\text {Ne}$$ 17 Ne and $$^{12}\text {C}$$ 12 C .