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Dynamic color screening in diffractive deep inelastic scattering

Ingelman, Gunnar; Pasechnik, Roman LU and Werder, Dominik (2016) In Physical Review D (Particles, Fields, Gravitation and Cosmology) 93(9).
Abstract

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... (More)

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.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review D (Particles, Fields, Gravitation and Cosmology)
volume
93
issue
9
publisher
American Physical Society
external identifiers
  • Scopus:84969850953
  • WOS:000376255900004
ISSN
1550-7998
DOI
10.1103/PhysRevD.93.094016
language
English
LU publication?
yes
id
f77d246b-af25-40c6-b93a-79cc92737cb3
date added to LUP
2016-08-18 19:56:08
date last changed
2017-01-30 10:39:09
@article{f77d246b-af25-40c6-b93a-79cc92737cb3,
  abstract     = {<p>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.</p>},
  articleno    = {094016},
  author       = {Ingelman, Gunnar and Pasechnik, Roman and Werder, Dominik},
  issn         = {1550-7998},
  language     = {eng},
  month        = {05},
  number       = {9},
  publisher    = {American Physical Society},
  series       = {Physical Review D (Particles, Fields, Gravitation and Cosmology)},
  title        = {Dynamic color screening in diffractive deep inelastic scattering},
  url          = {http://dx.doi.org/10.1103/PhysRevD.93.094016},
  volume       = {93},
  year         = {2016},
}