## Search for the Pentaquark via the P{sup 0}{sub {bar c}s}{r_arrow}{phi}{pi}p Decay

We report results of the first search for the pentaquark P{sub {bar c}s} which is predicted to be a doublet of states: P{sup 0}{sub {bar c}s}={vert_bar} {bar c}suud{r_angle} and P{sup {minus}}{sub {bar c}s}={vert_bar} {bar c}sddu{r_angle} . A search was made for the decay P{sup 0}{sub {bar c}s}{r_arrow} {phi}{pi}p in data from Fermilab experiment E791, in which a 500 GeV/c {pi}{sup {minus}} beam interacted with nuclear targets. We present upper limits at 90{percent} confidence level for the ratio of cross section times branching fraction of this decay to that for the decay D{sup {plus_minus}}{sub s}{r_arrow}{phi}{pi}{sup {plus_minus} } . The upper limitsmore »