  The probability that a randomly accelerated particle in two dimensions has
not yet left a simply connected domain ${\cal A}$ after a time $t$ decays as
$e^{-E_0t}$ for long times. The same quantity $E_0$ also determines the
confinement free energy per unit length $\Delta f=k_BT\thinspace E_0$ of a
semiflexible polymer in a narrow cylindrical pore with cross section ${\cal
A}$. From simulations of a randomly accelerated particle we estimate the
universal amplitude of $\Delta f$ for both circular and rectangular cross
sections.
