The quark-antiquark asymmetry of the nucleon sea from Lambda and (Lambda)over-bar fragmentation

We present a general analysis of the spin transfer for Lambda and <(Lambda) over bar> production in deep-inelastic scattering of polarized charged lept ons on the nucleon, and find that the pattern of different behaviors of Lam bda and <(Lambda)over bar> production observed by the E665 Collaboration su ggests the possibility of quark-antiquark asymmetries either in the quark t o Lambda fragmentation functions and/or in the quark and antiquark distribu tions of the target proton. We also point out that the strange-antistrange asymmetry of the nucleon sea may produce an observable contribution to the different behaviors of Lambda and <(Lambda)over bar> production. We find th at a softer (s) over bar(x) than s(x) as predicted by the light-cone baryon -meson fluctuation model of intrinsic quark-antiquark pairs of the nucleon sea might lead to a reasonable picture. However, the magnitude is still too small to explain the E665 data and the conclusion has also strong model-de pendence. This may suggest the importance of quark-antiquark asymmetry in t he quark to Lambda fragmentation functions, provided that the E665 data are confirmed. (C) 2000 Elsevier Science B.V. All rights reserved.