Answer :
The original particle that decays to produce protactinium-233 and a beta particle is thorium-233.
1. Thorium-233 is an unstable isotope that undergoes radioactive decay.
2. During the decay process, thorium-233 transforms into protactinium-233 and emits a beta particle.
3. This decay process is a common example of beta decay, where a neutron in the nucleus of the thorium-233 atom is transformed into a proton, releasing a beta particle (an electron) in the process.
In summary, thorium-233 is the original particle that decays to form protactinium-233 and emit a beta particle during the beta decay process.
