Dynamic color screening in diffractive deep inelastic scattering

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Dynamic color screening in diffractive deep inelastic scattering. / Ingelman, Gunnar; Pasechnik, Roman; Werder, Dominik.

In: Physical Review D (Particles, Fields, Gravitation and Cosmology), Vol. 93, No. 9, 094016, 18.05.2016.

Research output: Contribution to journalArticle

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TY - JOUR

T1 - Dynamic color screening in diffractive deep inelastic scattering

AU - Ingelman, Gunnar

AU - Pasechnik, Roman

AU - Werder, Dominik

PY - 2016/5/18

Y1 - 2016/5/18

N2 - We present a novel Monte Carlo implementation of dynamic color screening via multiple exchanges of semisoft gluons as a basic QCD mechanism to understand diffractive electron-proton scattering at the HERA collider. Based on the kinematics of individual events in the standard QCD description of deep inelastic scattering at the parton level, which at low x is dominantly gluon initiated, the probability is evaluated for additional exchanges of softer gluons resulting in an overall color singlet exchange leading to a forward proton and a rapidity gap as the characteristic observables for diffractive scattering. The probability depends on the impact parameter of the soft exchanges and varies with the transverse size of the hard scattering subsystem and is therefore influenced by different QCD effects. We account for matrix elements and parton shower evolution either via conventional DGLAP logQ2 evolution with collinear factorization or CCFM small x evolution with k factorization and discuss the sensitivity to the gluon density distribution in the proton and the importance of large log x contributions. The overall result is, with only two model parameters which have theoretically motivated values, a satisfactory description of the observed diffractive cross section at HERA obtained in a wide kinematical range.

AB - We present a novel Monte Carlo implementation of dynamic color screening via multiple exchanges of semisoft gluons as a basic QCD mechanism to understand diffractive electron-proton scattering at the HERA collider. Based on the kinematics of individual events in the standard QCD description of deep inelastic scattering at the parton level, which at low x is dominantly gluon initiated, the probability is evaluated for additional exchanges of softer gluons resulting in an overall color singlet exchange leading to a forward proton and a rapidity gap as the characteristic observables for diffractive scattering. The probability depends on the impact parameter of the soft exchanges and varies with the transverse size of the hard scattering subsystem and is therefore influenced by different QCD effects. We account for matrix elements and parton shower evolution either via conventional DGLAP logQ2 evolution with collinear factorization or CCFM small x evolution with k factorization and discuss the sensitivity to the gluon density distribution in the proton and the importance of large log x contributions. The overall result is, with only two model parameters which have theoretically motivated values, a satisfactory description of the observed diffractive cross section at HERA obtained in a wide kinematical range.

UR - http://www.scopus.com/inward/record.url?scp=84969850953&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.93.094016

DO - 10.1103/PhysRevD.93.094016

M3 - Article

VL - 93

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

T2 - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

SN - 1550-2368

IS - 9

M1 - 094016

ER -