RELATIVISTIC TREATMENT OF SPIN-TRANSFER OBSERVABLES IN QUASI-ELASTIC ((P)OVER-RIGHT-ARROW, (N)OVER-RIGHT-ARROW) SCATTERING

We calculate all spin-transfer observables for the quasielastic (($) o ver right arrow p, ($) over right arrow n) reaction in a relativistic planewave impulse approximation. The nuclear structure information is contained in a large set of nuclear response functions that are comput ed in nuclear matter using a relativistic random-phase approximation t o the Walecka model. A reduced value of the nucleon mass in the medium induces important dynamical changes in the residual isovector interac tion relative to its nonrelativistic counterpart. As a result, good ag reement is found for all spin observables - including the spin-longitu dinal to spin-transverse ratio - when compared to the original (q = 1. 72 fm(-1)) NTOF (neutron time-of-flight facility) experiment. In contr ast, the spin-longitudinal to spin-transverse ratio is underpredicted at g = 1.2 fm(-1) and overpredicted at q = 2.5 fm(-1). We comment on t he role of distortions as a possible solution to this discrepancy.