Quasiclassical description of bremsstrahlung accompanying $\alpha$ decay including quadrupole radiation
U. D. Jentschura, A. I. Milstein, I. S. Terekhov, H. Boie, H. Scheit, and D. Schwalm

We present a quasiclassical theory of $\alpha$ decay accompanied by bremsstrahlung with a special emphasis on the case of $^{210}$Po, with the aim of finding a unified description that incorporates both the radiation during the tunneling through the Coulomb wall and the finite energy $E_\gamma$ of the radiated photon up to $E_\gamma\sim Q_\alpha/\sqrt{\eta}$, where $Q_\alpha$ is the $\alpha$-decay $Q$-value and $\eta$ is the Sommerfeld parameter. The corrections with respect to previous quasiclassical investigations are found to be substantial, and excellent agreement with a full quantum mechanical treatment is achieved. Furthermore, we find that a dipole-quadrupole interference significantly changes the $\alpha$-$\gamma$ angular correlation. We obtain good agreement between our theoretical predictions and experimental results.

© 2008 The American Physical Society.