Three-body structure of A = 9 isobars (Be, Li, and C) and elastic proton scattering

Structure and three-body decay ofBe9resonances

“…The structure of 9 Be has been extensively studied, both theoretically [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and experimentally [17][18][19][20][21][22][23][24][25][26][27], but there are still large uncertainties in the structure and decay of the low-lying excited states. This is surprising and worrisome in view of the great effort and the expected rather accurate approximation as a simple three-body system where the intrinsic degrees of freedom are inactive.…”

Inelastic p 9Be scattering and halo structure of the J π = 1/2+ excited state of the 9Be nucleus

“…The 9 Ве nucleus is a strongly deformed stable nucleus whose quadrupole moment is Q = 52.88(38) mb [1]. It is loosely bound in the channels 9 Ве → 8 Ве + n [1] and 9 Ве → α + α + n [1] (the respective binding energies are ε = 1.67 MeV and ε = 1.57 MeV), this being a direct indication of its three-particle α + α + n structure.…”

“…It is loosely bound in the channels 9 Ве → 8 Ве + n [1] and 9 Ве → α + α + n [1] (the respective binding energies are ε = 1.67 MeV and ε = 1.57 MeV), this being a direct indication of its three-particle α + α + n structure. The wave functions calculated on the basis of the α + α + n model [2][3][4][5], which take this circumstance into account, describe well the static properties of the 9 Ве nucleus; electromagnetic form factors; and observables of elastic π 9 Ве, K 9 Ве, and p 9 Ве scattering [2][3][4][5][6][7][8][9]. The 9 Ве nucleus is a Borromean nucleus, since, within the α + α + n three-particle picture, there are no two components that could form a bound system (the same is true for 6 He in the α + n + n channel and for 11 Li in the 9 Li + n + n channel).…”

“…The most recent data obtained by studying some properties of a number of nuclei from 9 Ве to 48 Ar are presented in [10]. The Glauber model featuring densities obtained on the basis of the nonrelativistic microscopic Hartree-Fock formalism or the formalism of the relativistic mean-field model was used to describe reaction dynamics.…”

“…In order to find out how the diffuse structure of the excited state of 9 Ве affects inelastic proton scattering, we calculated the differential cross section at E = 180 MeV and compared our result with experimental data from [12], where the authors were able to observe the J π = 1/2 + level. 9 Ве NUCLEUS WITHIN THE 2αn MODEL Since the 9 Ве nucleus is strongly deformed, one cannot describe precisely its structure or energy spectrum on the basis of the shell model [20]. Also facts like the appearance of the pygmy resonance in the photoabsorption cross section for 9 Ве at E * = 4 MeV and an anomalously small spacing between oppositeparity levels are indicative of a distortion of the shell structure.…”