253 research outputs found
Reggeons in diffractive interactions in deep inelastic scattering at HERA
The "triple-Regge" analysis of subleading Reggeon contributions to the
diffractive structure function in DIS at HERA is presented. The recently
published data allow to estimate the only free parameter of the analysis
related to the ratio of the RRP and PPP couplings. The large value of this
ratio is prefered which is in agreement with analyses of soft hadronic
interactions. The role of the subleading Reggeons as well as pions for the fast
forward neutron production in diffractive processes is estimated. The forward
piN state production is also discussed.Comment: 6 pages, 2 figures, uses sprocl.sty and epsfig. To be published in
Proceedings of the Madrid low-x Workshop, Miraflores de la Sierra, June
18-21,199
Geometric scaling for the total gamma^* p cross section in the low x region
We observe that the saturation model of deep inelastic scattering, which
successfully describes inclusive and diffractive data at small x, predicts a
geometric scaling of the total gamma^* p cross section in the region of small
Bjorken variable x. The geometric scaling in this case means that the cross
section is a function of only one dimensionless variable tau = Q^2 R_0^2(x),
where the function R_0(x) (called saturation radius) decreases with decreasing
x. We show that the experimental data from HERA in the region x<0.01 confirm
the expectations of this scaling over a very broad region of Q^2. We suggest
that the geometric scaling is more general than the saturation model.Comment: 12 pages, 4 figures, LaTeX, revised version to appear in journal. 1
new figure, several new references added, extended discussion on saturation
radiu
Reggeon and pion contributions in semi-exclusive diffractive processes at HERA
A detailed analysis of semi-exclusive diffractive processes in e-p DIS at
HERA, with the diffractive final states in the forward direction is presented.
The contributions of the subleading f_2, \omega, a_2, \rho reggeons and the
pion exchanges to the diffractive structure function with the forward proton or
neutron are estimated. It is found that the (a_2,\rho) reggeons are entirely
responsible for the forward neutron production at x_P < 10^{-3}. The \pi N
production in the forward region is estimated using the Deck mechanism. The
significance of this reaction for the processes measured at HERA, especially
with the leading neutron, is discussed.Comment: Strongly revised version accepted for publication in Phys.Rev.D.
Latex, 14 pages with 5 eps figures include
Geometric Scaling in a Symmetric Saturation Model
We illustrate geometric scaling for the photon-proton cross section with a
very simple saturation model. We describe the proton structure function F2 at
small x in a wide kinematical range with an elementary functional form and a
small number of free parameters. We speculate that the symmetry between low and
high Q2 recently discovered in the data could be related to a well-known
symmetry of the two-gluon- exchange dipole-dipole cross section.Comment: 15 pages, 4 figure
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