The observation of active ${}^{44}\mathrm{Ti}$ in supernova remnants offers the potential to solve one of the most debated questions in modern astrophysics, the exact underlying explosion mechanism of core collapse supernovae (CCSNe). In particular, a comparison between the predicted synthesized yield of ${}^{44}\mathrm{Ti}$ and the ejected flux is expected to allow for a determination of the mass cut of the star. Unfortunately, such comparisons are currently severely hindered by large uncertainties in the nuclear reactions governing the production and destruction of ${}^{44}\mathrm{Ti}$. On this note, the astrophysical ${}^{45}\mathrm{V}(p,\gamma ){}^{46}\mathrm{Cr}$ reaction is expected to play a decisive role. We present the first experimental information on resonant states in the ${}^{45}\mathrm{V}(p,\gamma ){}^{46}\mathrm{Cr}$ reaction. Excitation energies have been measured with high precision for ten previously unknown, low-spin, proton-unbound states in ${}^{46}\mathrm{Cr}$, and spin-parity-assignment constraints have been made using observed $\gamma$-decay patterns and shell-model calculations. We find that an $\ell =1$ resonance at 714 keV dominates the ${}^{45}\mathrm{V}(p,\gamma ){}^{46}\mathrm{Cr}$ reaction for the entire temperature range of $\alpha$-rich freezeout. Moreover, the nominal rate is found to be $\sim 25–50\%$ of previous estimates for $T>1.2\mathrm{GK}$, indicating an increase in ${}^{44}\mathrm{Ti}$ production in CCSNe of $\sim 20–35\%$.

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• Energy levels
• Explosive burning
• Fusion evaporation reactions
• Nuclear reaction rates
• Nucleosynthesis in explosive environments
• 39 ≤ A ≤ 58
• Spectrometers & spectroscopic techniques