  We have studied the dynamics of electrons in single wall carbon nanotubes
using femtosecond time-resolved photoemission. The lifetime of electrons
excited to the pi* bands is found to decrease continuously from 130 fs at 0.2
eV down to less than 20 fs at energies above 1.5 eV with respect to the Fermi
level. This should lead to a significant lifetime--induced broadening of the
characteristic van Hove singularities in the nanotube DOS.
