Triple-differential cross section of the 208Pb(6Li,αd)208Pb Coulomb breakup and astrophysical S-factor of the d(α,γ)6Li reaction at extremely low energies

A method of calculation of the triple-differential cross section of the 208Pb(6Li,αd)208Pb Coulomb breakup at astrophysically relevant energies E of the relative motion of the breakup fragments, taking into account the three-body (α-d-208Pb) Coulomb effects and the contributions from the E1- and E2-multipoles, including their interference, has been proposed. The new results for the astrophysical S-factor of the direct radiative capture d(α,γ)6Li reaction at E≤250 keV have been obtained. It is shown that the experimental triple-differential cross section of the 208Pb(6Li,αd)208Pb Coulomb breakup can also be used to give information about the value of the modulus squared of the nuclear vertex constant for the virtual decay 6Li→α+d