COLOR-OCTET FRACTION IN J PSI PRODUCTION AND ABSORPTION/

The cross section between a c (c) over bar pair and a nucleon is small and sensitive to the c-(c) over bar separation if the pair is in a co lor-singlet state, but very large and insensitive to the separation if it is in a color-octet state. We use this property in an absorption m odel involving both color components to deduce the color structure of c (c) over bar pairs produced in pA --> psi X reactions. Our analysis shows that the NA3, NA38, and E772 data are not inconsistent with the theoretical picture that color-octet and color-singlet precursors are produced in roughly equal proportions if the produced color-singlet pr ecursors are pointlike and transparent. However, if the color-singlet precursors are not transparent but have a cross section of a few mb, t hese data do show a definite preference for a larger fraction of color -singlet precursors. In either case, the color-octet fraction increase s with x(F), approaching close to unity as x(F) increases to about 0.5 .