Neutrino absorption efficiency of an40Ardetector from the β decay of40Ti

We studied $\beta$-delayed proton and $\gamma$ emission from ${}^{40}\mathrm{Ti}$ decay. We found $t_{1/2}=52.7\mathrm{}\pm 1.5\hspace{0.5em}\mathrm{ms}$ and observed 28 proton groups that we organized into a ${}^{40}\mathrm{Ti}$ decay scheme with 21 branches. The reduced transition strengths of these decay branches were then used to compute the neutrino detection efficiency of the ICARUS liquid argon time-projection chamber. We found ${}^{40}\mathrm{Ar}(\nu ,e)$ cross sections (for an electron energy threshold $W=5\mathrm{}\hspace{0.5em}\mathrm{MeV}$) of $(14.0\mathrm{}\pm 0.3)\times {10}^{-43}\hspace{0.5em}{\mathrm{cm}}^2,$ $(75.1\mathrm{}\pm 1.8)\times {10}^{-43}\hspace{0.5em}{\mathrm{cm}}^2,$ and $(3.2\mathrm{}\pm 0.1)\times {10}^{-41}\hspace{0.5em}{\mathrm{cm}}^2$ for ${}^8\mathrm{B}$ neutrinos, hep neutrinos, and supernova neutrinos characterized by a temperature of 4.5 MeV.