  We obtain sharp asymptotic estimates for hitting probabilities of a critical
branching Brownian motion in one dimension with killing at 0 We also obtain
sharp asymptotic formulas for the tail probabilities of the number of particles
killed at 0. In the special case of double-or-nothing branching, we give exact
formulas for both the hitting probabilities, in terms of elliptic functions,
and the distribution of the number of killed particles.
