A study of the centrally produced p (p) over bar, p (p) over bar pi(0), p (
p) over bar pi(+)pi(-) and Lambda Lambda channels has been performed in pp
collisions using an incident beam momentum of 450 GeV/c. No significant new
structures are observed in the mass spectra, however, important new inform
ation on the production dynamics is obtained. A systematic study of the pro
duction properties of these systems has been performed and it is found that
these systems are not produced dominantly by double Pomeron exchange. (C)
1999 Published by Elsevier Science B.V. All rights reserved.