Role of virtual break-up of projectile in astrophysical fusion reactions

We study the effect of virtual Coulomb breakup, commonly known as the dipole polarizability, of the deuteron projectile on the astrophysical fusion reaction ³He(d,p)⁴He. We use the adiabatic approximation to estimate the potential shift due to the E1 transition to the continuum states in the deuteron and compute the barrier penetrability in the WKB approximation. We find that the enhancement of the penetrability due to the deuteron breakup is too small to resolve the longstanding puzzle observed in laboratory measurements that the electron screening effect is surprisingly larger than theoretical prediction based on an atomic physics model. The effect of ³He breakup in the ³He(d,p)⁴He reaction, as well as the ⁷Li breakup in the ⁷Li(p,α)⁴He reaction is also discussed.