Calculation of the peripheral partial amplitudes for the anamal and usual mechanisms of consecutive two protons transfer in the peripheral nuclear A(X,Y)B reaction, induced by unstable light nuclei at low energies

Full text: In the present work the peripheral two protons (p1 and p2) transfer A(X,Y)B reaction induced by unstable light nuclei at low energies is considered. Herein X=((Yp2) +p1) and B=((Ap1)+p2) in which proton p1(p2) is loosely bound in the nucleus X (B) with binding energy εX(εB), and the binding energies of the protons (p2 and p1), ε(Yp2) and ε(Ap1), in the bound (Yp2 ) and (Ap1) states, respectively, satisfy the conditions ε(Yp2)>>εX , ε(Ap1) >> εB,εX≅εB. Taking into account the fact that the main contribution to the amplitude of the reaction under consideration comes from the peripheral partial amplitudes for ι>>1, the explicit forms of the peripheral partial amplitudes Mι for ι>>1, which is dictated by the nearest to the physical region -1≤cosθ≤1 singularity point cosθ= ζ>1(θ is the scattering angle in the c.m.s.) and is connected with the singularity of the Coulomb vertex form factors for the virtual decays X→(Yp2)+p1 and (Ap1)+p2→B(an anamal mechanism), and of the peripheral partial amplitudes MιDWBA , which correspond to a mechanism of consecutive transfer of the conventional DWBA, have been found. The asymptotical expressions for Mι and MιDWBA for ι>>1 show the different dependence onι. Comparison of the Mι and MιDWBA for ι>>1 from each other has been made for the peripheral transfer reactions 10B (12N,10B)12N , 15N(12 N,10B) 17F , 6Li(12N,10B)8B and 15N(13N, 11B) 17F at projectile energies E from 10 MeV up to 100 MeV and lower limits of values of l (ι>>1) beginning with them the modulus ratio of Rι /=Mι /MιDWBA / ≥1 as a function of ι for different energies E have been determined. (authors)