On the absorption of antibaryons in nuclei

Antiproton ((p) over bar) and antilambda (<(Lambda)over bar>) production ha s been measured for minimum bias in p+A collisions and central A(1)+A(2) co llisions at the CERN-SPS by the collaborations NA35/49 and NA44. The measur ements are extrapolated from rapidity distributions to absolute minimum bia s cross sections. It is shown that the (p) over bar cross sections divided by A(1).A(2) follow an exponential trend as a function of a characteristic length obtained from a Glauber type absorption model, while the <(Lambda)ov er bar> cross sections divided by A(1).A(2) are constant. The exponential t rend also holds for (p) over bar production at the lower energies of the Br ookhaven AGS. A discussion of the physics interpretation of the established trends in terms of an effective absorption cross section is presented.