A new analysis of diffractive deep-inelastic ep scattering at HERA is presented using data taken in 1994 with the Hi detector corresponding to an integrated luminosity of ~ 2pb-1. The cross section is measured in terms of a diffractive structure function F^^[0,Q3 , Up) of the proton over the kinematic range 2.5 < <22 < 65 GeV2, 0.01 < /3 < 0.9 and 0.0001 < xP < 0.05. The dependence of F2°'3' on xjp is found not to depend on Q2 but to depend on /3, demonstrating that the factorisation of the "f*p cross section into a universal diffractive flux (depending only on xjp) and a single structure function (depending only on /3 and Q2)is'not tenable. The data are consistent with an interpretation in which two individually factorisable components contribute to P2 ' '. They may be identified with pomeron (JP) and meson Regge trajectories with xp dependencies cc x Jnp, tp"M where njp = 1.29 ± 0.03(stat)±0.07(syst) and nM = 0-3 ± 0.3(stat)±0.6(syst). The Q2 and 0 dependences of F2 are examined in the form of F~(f3,Q2) after integrating over the dependence on xjp. For different /, violations of scale invariance are observed which are consistent with a substantial gluon component in diffractive exchange. When confronted with the leading order DGLAP evolution equations in perturbative QCD, the data yield first estimates of the partonic content of diffractive exchange. Measurements are presented of energy flow, inclusive charged particle spectra and inclusive charm production in diffractive interactions at high Q2, and of diffractive di-jet production at both Q2 = 0 and Q2 > 0. These characteristics of the final state are consistent with calculations based on a partonic model of e-P interactions in which the parton distributions are taken from the QCD analysis of F°[S).
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