blois-2003

Diffractive Dijets with Leading AntiprotonpNDSDjet0jet0jetjetDPE jet jetpppIPIPη_ pp 0 ηη p (not detected)ppppIPThe diffractive structure functionpx BjxpBjF NDBjorken-x of antiproton=1( x,Qs2)F SD ( ξ,t,x,Q∑# jets2)EiTe−ηiNucleon structure functionDiffractive structure functionISSUES:1) QCD factorization >2F SD ( ξ,t,x,Q ) is F SD universal?2) Regge factorization >FSD2( ξ , t,β , Q ) f ( ξ,t)× fβ ≡ x /ξ=IP−fluxIP( β , Qmomentum fraction of parton in IP2)?METHOD of measuring F SD : measure ratio R(ξ,t) of SD/ND rates for given ξ,tset R(ξ,t)=F SD /F NDevaluate F SD = R * F ND