  Unravelling the main initial dynamics responsible for chiral recognition is a
key stepin the understanding of many biological processes. However this
challenging task requires a sensitive enantiospecic probe to investigate
molecular dynamics on their natural femtosecond timescale. Here we show that,
in the gas phase, the ultrafast relaxationdynamics of photoexcited chiral
molecules can be tracked by recording Time-ResolvedPhotoElectron Circular
Dichroism (TR-PECD) resulting from the photoionisation bya circularly polarized
probe pulse. A large forward/backward asymmetry along theprobe propagation axis
is observed in the photoelectron angular distribution. Its evolution with
pump-probe delay reveals ultrafast dynamics that are inaccessible in
theangle-integrated photoelectron spectrum nor via the usual electron emission
anisotropyparameter ($\beta$). PECD, which originates from the electron
scattering in the chiral molecular potential, appears as a new sensitive
observable for ultrafast molecular dynamicsin chiral systems.
