Excitation of multipolar transitions in nuclei by twisted photons

Abstract: The explicit expression for the probability of absorption of a twisted photon by an atomic nucleus has been obtained. It is shown that photoabsorption obeys the selection rule $j\geqslant|m_\gamma|$, where $j$ is the multipolarity of the nuclear transition, when the nuclei lie near the axis along which a twisted photon with a projection of the total angular momentum $m_\gamma$ propagates. In the long-wave limit, the main contribution to the probability of absorption of a twisted photon comes from the multipole transition with $j=|m_\gamma|$. The absorption coefficient for twisted photons in a target consisting of many nuclei has been found.