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Title: Measurement of dijet cross-sections in low $${\rm Q}^2$$ ep collisions and the extraction of an effective parton density for the virtual photon

Abstract

The triple-differential dijet cross-section, d 3 σ e p / d Q 2 d E t ¯ 2 d x γ j e t s , is measured with the H1 detector at HERA as a function of the photon virtuality Q 2 , the fraction of the photon's momentum carried by the parton entering the hard scattering, \x γ j e t s , and the square of the mean transverse energy, E t ¯ 2 , of the two highest E t jets. Jets are found using a longitudinal boost-invariant k T clustering algorithm in the γ p center of mass frame. The measurements cover the ranges 1.6 < Q 2 < 80 GeV 2 in virtuality and 0.1 < y < 0.7 in inelasticity y. The results are well described by leading order QCD models which include the effects of a resolved component to the virtual photon. Models which treat the photon as point-like fail to describe the data. An effective leading order parton density for the virtual photon is extracted as a function of the photon virtuality, the probing scale and the parton momentum fraction. The x γ and probing scale dependences of the parton density show characteristic features of photon structure, and a suppression of this structure with increasing Q 2 is seen.

Authors:
Publication Date:
Research Org.:
Univ. of California, Davis, CA (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
The H1 Collaboration
OSTI Identifier:
1511283
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
European Physical Journal. C, Particles and Fields
Additional Journal Information:
Journal Volume: 13; Journal Issue: 3; Journal ID: ISSN 1434-6044
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; transverse energy; scale dependence; virtual photon; momentum fraction; parton density

Citation Formats

Adloff et al., C. Measurement of dijet cross-sections in low ${\rm Q}^2$ ep collisions and the extraction of an effective parton density for the virtual photon. United States: N. p., 2000. Web. doi:10.1007/s100520000144.
Adloff et al., C. Measurement of dijet cross-sections in low ${\rm Q}^2$ ep collisions and the extraction of an effective parton density for the virtual photon. United States. doi:10.1007/s100520000144.
Adloff et al., C. Fri . "Measurement of dijet cross-sections in low ${\rm Q}^2$ ep collisions and the extraction of an effective parton density for the virtual photon". United States. doi:10.1007/s100520000144. https://www.osti.gov/servlets/purl/1511283.
@article{osti_1511283,
title = {Measurement of dijet cross-sections in low ${\rm Q}^2$ ep collisions and the extraction of an effective parton density for the virtual photon},
author = {Adloff et al., C.},
abstractNote = {The triple-differential dijet cross-section, d 3 σ e p / d Q 2 d E t ¯ 2 d x γ j e t s , is measured with the H1 detector at HERA as a function of the photon virtuality Q 2 , the fraction of the photon's momentum carried by the parton entering the hard scattering, \x γ j e t s , and the square of the mean transverse energy, E t ¯ 2 , of the two highest E t jets. Jets are found using a longitudinal boost-invariant k T clustering algorithm in the γ ∗ p center of mass frame. The measurements cover the ranges 1.6 < Q 2 < 80 GeV2 in virtuality and 0.1 < y < 0.7 in inelasticity y. The results are well described by leading order QCD models which include the effects of a resolved component to the virtual photon. Models which treat the photon as point-like fail to describe the data. An effective leading order parton density for the virtual photon is extracted as a function of the photon virtuality, the probing scale and the parton momentum fraction. The xγ and probing scale dependences of the parton density show characteristic features of photon structure, and a suppression of this structure with increasing Q 2 is seen.},
doi = {10.1007/s100520000144},
journal = {European Physical Journal. C, Particles and Fields},
number = 3,
volume = 13,
place = {United States},
year = {2000},
month = {2}
}

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