Speaker
Description
Proton decay represents one of the key signatures of grand unified theories (GUTs). Among the most widely used detector technologies are liquid argon time projection chambers, water Cherenkov detectors and liquid scintillator detectors.
For protons bound in the nuclei, the decay signature is affected by nuclear effects like Fermi motion and final-state interactions (FSI). In contrast, the free proton from the hydrogen content of water and liquid scintillator is not affected by these effects, resulting in a better-defined kinematic signature. The bound proton case is further complicated by the limited experimental data for the cross sections of pion- and kaon- nucleus interactions in the energy region of interest for proton decay. Our analysis focuses on the Fermi motion and FSI for the nuclei relevant for present and potential future proton decay searches including Ar, O and Xe. The studied channels were $p \rightarrow K^+ + \bar{\nu}$ and $p \rightarrow \pi^+ + \bar{\nu}$. We calculated the energy distributions of the charged decay products based on the Fermi motion of the protons. In addition, using parameterizations and extrapolations based on available experimental data, we determined pion-, kaon- nucleus cross sections, mean free paths and interaction probabilities.
Finally, the de-excitation of the residual nucleus which is a mode-independent signal for proton decay is also discussed.