  High resolution X-ray spectra of accreting stellar mass Black Holes reveal
the presence of accretion disc winds, traced by high ionisation Fe K lines.
These winds appear to have an equatorial geometry and to be observed only
during disc dominated states in which the radio jet is absent. Accreting
neutron star systems also show equatorial high ionisation absorbers. However,
the presence of any correlation with the accretion state has not been
previously tested. We have studied EXO 0748-676, a transient neutron star
system, for which we can reliably determine the accretion state, in order to
investigate the Fe K absorption/accretion state/jet connection. Not one of
twenty X-ray spectra obtained in the hard state revealed any significant Fe K
absorption line. However, intense Fe ${\scriptsize{\rm XXV}}$ and Fe
${\scriptsize{\rm XXVI}}$ (as well as a rarely observed Fe ${\scriptsize{\rm
XXIII}}$ line plus S ${\scriptsize{\rm XVI}}$; a blend of S ${\scriptsize{\rm
XVI}}$ and Ar ${\scriptsize{\rm XVII}}$; Ca ${\scriptsize{\rm XX}}$ and Ca
${\scriptsize{\rm XIX}}$, possibly produced by the same high ionisation
material) absorption lines ($EW_{\rm Fe~{XXIII-XXV}}=31\pm3$ eV, $EW_{\rm
Fe~XXVI}=8\pm3$ eV) are clearly detected during the only soft state
observation. This suggests that the connection between Fe K absorption and
states (and anticorrelation between the presence of Fe K absorption and jets)
is also valid for EXO 0748-676 and therefore it is not a unique property of
black hole systems but a more general characteristic of accreting sources.
