  In this Paper we report on radio (VLA and ATCA) and X-ray (RXTE, Chandra and
Swift) observations of the outburst decay of the transient black hole candidate
H1743-322 in early 2008. We find that the X-ray light curve followed an
exponential decay, leveling off towards its quiescent level. The exponential
decay timescale is ~4 days and the quiescent flux corresponds to a luminosity
of 3x10^32 (d/7.5 kpc)^2 erg/s. This together with the relation between
quiescent X-ray luminosity and orbital period reported in the literature
suggests that H1743-322 has an orbital period longer than ~10 hours. Both the
radio and X-ray light curve show evidence for flares. The radio - X-ray
correlation can be well described by a power-law with index ~0.18. This is much
lower than the index of 0.6-0.7 found for the decay of several black hole
transients before. The radio spectral index measured during one of the radio
flares while the source is in the low-hard state, is -0.5+-0.15, which
indicates that the radio emission is optically thin. This is unlike what has
been found before in black hole sources in the low-hard state. We attribute the
radio flares and the low index for the radio - X-ray correlation to the
presence of shocks downstream the jet flow, triggered by ejection events
earlier in the outburst. We find no evidence for a change in X-ray power law
spectral index during the decay, although the relatively high extinction of N_H
=2.3x10^22 cm^-2 limits the detected number of soft photons and thus the
accuracy of the spectral fits.
