Eur. Phys. J. A (2007) 33: 29-38
https://doi.org/10.1140/epja/i2007-10418-2

Regular Article - Nuclear Structure and Reactions

Electromagnetic proton-neutron knockout off ¹⁶O : New achievements in theory

¹ Dipartimento di Fisica Nucleare e Teorica, Università degli Studi di Pavia, and Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, I-27100, Pavia, Italy
² Dipartimento di Fisica, Università degli Studi di Trento, and Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Trento, I-38100, Povo (Trento), Italy
³ European Center for Theoretical Studies in Nuclear Physics and Related Areas, I-38100, Villazzano (Trento), Italy

^* e-mail: Carlotta.Giusti@pv.infn.it

Received: 5 June 2007
Accepted: 28 June 2007
Published online: 31 July 2007

Abstract

Results for the cross-sections of the exclusive ¹⁶O(e, e'pn)¹⁴N and ¹⁶O(γ, pn)¹⁴N knockout reactions are presented and discussed in different kinematics. In comparison with earlier work, a complete treatment of the center-of-mass (CM) effects in the nuclear one-body current is considered in connection with the problem of the lack of orthogonality between initial bound and final scattering states. The effects due to CM and orthogonalization are investigated in combination with different treatments of correlations in the two-nucleon overlap function and for different parametrizations of the two-body currents. The CM effects lead in super-parallel kinematics to a dramatic increase of the ¹⁶O(e, e'pn) cross-section to the 1₂ ⁺ excited state (3.95MeV) of ¹⁴N . In all the situations considered the results are very sensitive to the treatment of correlations. A crucial role is played by tensor correlations, but also the contribution of long-range correlations is important.