The sensitivity of r-process nucleosynthesis to beta-delayed neutron emission probabilities

In the classic picture of rapid neutron capture, or r-process, nucleosynthesis, the heaviest elements are formed far from stability in conditions of $(n,\gamma)$-$(\gamma,n)$ equilibrium. When equilibrium fails, neutron captures, photodissociations, and beta decays all compete as material moves back toward stability. The beta decays of the very neutron-rich nuclei created in the r-process are often followed by the emission of one or more neutrons. This beta-delayed neutron emission plays a key role in setting the final abundance pattern during the decay back to stability. Here we describe how beta-delayed neutron emission probabilities determine the availability of neutrons for capture at late times in the r-process, and discuss the importance of individual $P_{n}$ values in fixing the details of the r-process abundance pattern. We will point out the beta-delayed neutron emission probabilities that most strongly influence the r-process abundance pattern in a range of possible astrophysical scenarios.