Speaker
Description
The ideal nuclear picture derived from the shell model considers the nucleus as composed of defined nuclear states fully occupied by nucleons. However in a real nucleus correlation effects [1] lead to the mixing of configurations, reducing the occupancies as the Fermi energy is reached. For stable nuclei the (e,e’p) data reveals a quenching factor a round ~ 0.7 with respect to the independent-particle shell model [2], but the situation in the regions of beta-instability is still greatly unknown. Neutron quenching factors for exotic 31S, 32Cl, and 33Ar determined with knockout reactions decrease to around ~ 0.5 [3]. For the case of 32Ar a small value of ~ 0.25 was reported, showing the effect of correlations on neutron subshells N=15,16 far from stability. For Ne isotopes, spectroscopic factors for 23Ne and stable isotopes are given in [4], and the case of 25Ne was investigated in [5]. On the other hand, there is very few spectroscopic information available for the proton orbitals. Detailed knowledge of proton rich Ar and Ne isotopes is relevant for understanding the formation of proton haloes and skins in the vicinity of the drip lines [6, 7]. The present proposal aims to exploring the evolution of single-particle occupancies on sd-shell nuclei close to the drip lines. The novel Isolde Solenoidal Spectrometer recently commissioned at ISOLDE [8] can be used to study the spectroscopic factors to the ground and low excited states in inverse kinematics.
References
[1] W. Dickhoff, C. Barbieri, Prog. Nucl. Part. Sci. 52 (2004) 377.
[2] V.R. Pandharipande et al., Rev. Mod. Phys. 69 (1997) 981.
[3] A. Gade et al., Eur. Phys. J. A 25, s01, (2005) 251–253; Phys. Rev. C 69 (2004) 034311. [4] M. B. Tsang et al., Phys. Rev. Lett. 95 (2005) 222501.
[5] W N Catford et al 2005 J. Phys. G: Nucl. Part. Phys. 31 S1655.
[6] A. Ozawa et al., Nuclear Physics A 709 (2002) 60–72.
[7] R. Kanugo et al, Eur. Phys. J. A 25, 327–330 (2005).
[8] T. L. Tang et al. Phys. Rev. Lett. 124 (2020) 062502.
