Polarization, Motion, and Fragmentation: Exploring the Role of Quarks in the Nucleon Through Semi-Inclusive Longitudinal Spin Asymmetries at HERMES

This dissertation presents an analysis of deep inelastic scattering data, with polarized electron beam and polarized hydrogen and deuterium gas targets, taken by the HERMES collaboration at the DESY laboratory in Hamburg, Germany. Double-spin Born asymmetries are presented. Semi-inclusive (hadron-identified) asymmetries are binned in the parton momentum fraction (Bjorken-x), hadron energy fraction, z, and transverse momentum. Kinematic dependences of these asymmetries are explored. A leading order purity extraction of the quark polarizations and helicity densities is performed using these three-dimensionally binned semi-inclusive asymmetries and purities matrices generated with a Lund-String fragmentation Monte-Carlo simulation. Additionally, a new rigorous procedure for tuning this phenomenological model and estimating its contribution to the systematic uncertainty of the quark polarizations is included. Other subjects explored are the influence of the target remnant on often trusted fragmentation symmetry assumptions and an improved procedure for correcting the smearing effects of limited detector resolution and QED radiation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Rubin, Joshua George

Contributors dc:contributor

• Matthias Grosse-Perdekamp

• Physics, Nuclear

Language dc:language

eng

Identifier

(MiAaPQ)AAI3392461

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/80619