C. Adloff et al., INCLUSIVE MEASUREMENT OF DIFFRACTIVE DEEP-INELASTIC EP SCATTERING, Zeitschrift fur Physik. C, Particles and fields, 76(4), 1997, pp. 613-629
A measurement is made of the cross section for the process ep --> eXY
in deep-inelastic scattering with the HZ detector at HERA. The cross s
ection is presented in terms of a differential structure function F-2(
D(3))(x(p), beta, Q(2)) Of the proton over the kinematic range 4.5 < Q
(2) < 75GeV(2) The dependence of F-2(D(3)) On x(p) is found to vary wi
th beta, demonstrating that a factorisation of F-2(D(3)) with a single
diffractive nux independent of beta and Q(2) is not tenable, An inter
pretation in which a leading diffractive exchange and a subleading reg
geon contribute to F-2(D(3)) reproduces well the x(p) dependence of F-
2(D(3)) with values for the pomeron and subleading reggeon intercepts
of alpha(p)(0) = 1.203 +/- 0.020(stat.)+/-0.013(sys.)(-0.035)(+0.030)(
model) and alpha(R)(0) = 0.50 +/- 0.11(stat.)+/-0.11(sys.)(-0.10)(+0.0
9)(model), respectively. A fit is performed of the data using a QCD mo
tivated model, in which parton distributions are assigned to the leadi
ng and subleading exchanges. Bn this model, the majority of the moment
um of the pomeron must be carried by gluons in order for the data to b
e well described.