The charged current neutrino cross section for solar neutrinos, and background to BBz\ experiments

Solar neutrinos can interact with the source isotope in neutrinoless double beta decay experiments through charged current and neutral current interactions. The charged-current product nucleus will then beta decay with a Q-value larger than the double beta decay Q-value. As a result, this process can populate the region of interest and be a background to the double beta decay signal. In this paper we estimate the solar neutrino capture rates on three commonly used double beta decay isotopes, \nuc{76}{Ge}, \nuc{130}{Te}, and \nuc{136}{Xe}. We then use the decay scheme of each product nucleus to estimate the possible background rates in those materials. As half-life sensitivities in future experiments approach $10^{28}$ y, this background will have to be considered.