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Polarization, motion, and fragmentation. Exploring the role of quarks in the nucleon through semi-inclusive longitudinal spin asymmetries at HERMES

Abstract

The motivation for this work was to improve upon prior analyses that extracted the quark helicity distributions, {delta}(x), of the proton. Chapter 4 contains several new double-spin asymmetries which are results in their own right. The ph? dependence is plotted for the first time with HERMES data which is uniquely hadron separated. The hadron charge difference asymmetry is presented which, in combination with the quark helicity densities can put limits on fragmentation symmetry breaking in semi-inclusive DIS. Additionally, a novel method of unfolding yields (reducing smearing effects from detector resolution limitations and QED radiation) was developed and presented here for the first time which potentially allows new kinds of asymmetries to be constructed which were unavailable before. Also, this chapter describes the method by which the first ever three dimensionally binned SIDIS double-spin asymmetries were produced. These asymmetries, which will be used as the data inputs for the {delta}(x) extraction, are valuable inputs to world fits being performed by theorists. Chapter 5 further explores this idea of fragmentation symmetry breaking with Monte Carlo studies of fragmentation functions. These studies test assumptions which are frequently made in the interpretation of asymmetries like the hadron charge difference of the prior chapter and  More>>
Publication Date:
Nov 15, 2009
Product Type:
Thesis/Dissertation
Report Number:
DESY-THESIS-2009-045
Resource Relation:
Other Information: TH: Diss. (Dr.phil.)
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; SEMI-INCLUSIVE INTERACTIONS; POLARIZATION-ASYMMETRY RATIO; ELECTRON-PROTON INTERACTIONS; GEV RANGE 10-100; POLARIZED BEAMS; ELECTROPRODUCTION; ELECTRONS; PIONS PLUS; PIONS MINUS; KAONS PLUS; KAONS MINUS; MULTIPLICITY; EXPERIMENTAL DATA
OSTI ID:
21246539
Research Organizations:
Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Illinois Univ., Urbana-Champaign, IL (United States). Graduate Coll.
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Other: ISSN 1435-8085; TRN: DE09FD998
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21246539
Submitting Site:
DEN
Size:
129 pages
Announcement Date:
Dec 22, 2009

Citation Formats

Rubin, Joshua George. Polarization, motion, and fragmentation. Exploring the role of quarks in the nucleon through semi-inclusive longitudinal spin asymmetries at HERMES. Germany: N. p., 2009. Web.
Rubin, Joshua George. Polarization, motion, and fragmentation. Exploring the role of quarks in the nucleon through semi-inclusive longitudinal spin asymmetries at HERMES. Germany.
Rubin, Joshua George. 2009. "Polarization, motion, and fragmentation. Exploring the role of quarks in the nucleon through semi-inclusive longitudinal spin asymmetries at HERMES." Germany.
@misc{etde_21246539,
title = {Polarization, motion, and fragmentation. Exploring the role of quarks in the nucleon through semi-inclusive longitudinal spin asymmetries at HERMES}
author = {Rubin, Joshua George}
abstractNote = {The motivation for this work was to improve upon prior analyses that extracted the quark helicity distributions, {delta}(x), of the proton. Chapter 4 contains several new double-spin asymmetries which are results in their own right. The ph? dependence is plotted for the first time with HERMES data which is uniquely hadron separated. The hadron charge difference asymmetry is presented which, in combination with the quark helicity densities can put limits on fragmentation symmetry breaking in semi-inclusive DIS. Additionally, a novel method of unfolding yields (reducing smearing effects from detector resolution limitations and QED radiation) was developed and presented here for the first time which potentially allows new kinds of asymmetries to be constructed which were unavailable before. Also, this chapter describes the method by which the first ever three dimensionally binned SIDIS double-spin asymmetries were produced. These asymmetries, which will be used as the data inputs for the {delta}(x) extraction, are valuable inputs to world fits being performed by theorists. Chapter 5 further explores this idea of fragmentation symmetry breaking with Monte Carlo studies of fragmentation functions. These studies test assumptions which are frequently made in the interpretation of asymmetries like the hadron charge difference of the prior chapter and suggest that these assumptions should be approached with some caution. Also, a technique for tuning and more importantly propagating systematic uncertainty through non-analytic Monte Carlo models, like the Lund-String model which provides an essential input to the {delta}(x) extraction, is developed (orig.)}
place = {Germany}
year = {2009}
month = {Nov}
}