Measurement and interpretation of F{sub 2}{sup D(3)}

Journal Article · Sun Apr 20 00:00:00 EDT 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.53713· OSTI ID:21167574

Dirkmann, M ^[1]

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1. Lehrstuhl Exp. Phys. 5, Universitaet Dortmund (Germany)

An analysis of diffractive deep-inelastic ep scattering at HERA is presented using data taken in 1994 with the H1 detector corresponding to an integrated luminosity of {approx}2 pb{sup -1}. The cross section is measured in terms of a diffractive structure function F{sub 2}{sup D(3)}({beta},Q{sup 2},x{sub P}) of the proton over the kinematic range 2.5<Q{sup 2}<65 GeV{sup 2}, 0.01<{beta}<0.9 and 0.0001<x{sub P}<0.05. The dependence of F{sub 2}{sup D(3)} on x{sub P} is found not to depend on Q{sup 2} but to depend on {beta}, demonstrating that the factorisation of the {gamma}*p cross section into a universal diffractive flux (depending only on x{sub P} and t) and a single structure function (depending only on {beta} and Q{sup 2}) is not tenable. The data are consistent with an interpretation in which two individually factorisable components contribute to F{sub 2}{sup D(3)}. They may be identified with the exchange of pomeron (P) and meson (M) Regge trajectories with x{sub P} dependencies {proportional_to}x{sub P}{sup -(2{alpha}{sub P}{sup -1})}, x{sub P}{sup -(2{alpha}{sub M}{sup -1})} with {alpha}{sub P}(0)=1.18{+-}0.20(stat){+-}0.04(syst) and {alpha}{sub M}(0)=0.6{+-}0.1(stat){+-}0.3(syst). The Q{sup 2} and {beta} dependences of F{sub 2}{sup D(3)} are examined by integrating F{sub 2}{sup D(3)} over x{sub P}. For different {beta}, 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 which is dominated by a leading gluon at the starting scale of Q{sub 0}{sup 2}=2.5 GeV{sup 2}.

• OSTI ID: 21167574
• Journal Information: AIP Conference Proceedings, Vol. 407, Issue 1; Conference: 5. international workshop on deep inelastic scattering and QCD, Chicago, IL (United States), 14-18 Apr 1997; Other Information: DOI: 10.1063/1.53713; (c) 1997 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CROSS SECTIONS
DEEP INELASTIC SCATTERING
FOUR MOMENTUM TRANSFER
GLUONS
HERA STORAGE RING
MESONS
MULTIPARTICLE SPECTROMETERS
PARTICLE IDENTIFICATION
PARTICLE KINEMATICS
PHOTON-PROTON INTERACTIONS
POMERANCHUK PARTICLES
PROTONS
QUANTUM CHROMODYNAMICS
REGGE TRAJECTORIES
SCALE INVARIANCE
STRUCTURE FUNCTIONS