Measurement of the Double Spin Asymmetry in π⁺ electroproduction with CLAS

Thesis/Dissertation · Fri Dec 01 00:00:00 EST 2000

DOI:https://doi.org/10.2172/824907· OSTI ID:824907

Vita, Raffaella De ^[1]

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1. Univ. of Genoa (Italy)

The present thesis describes the measurement of the double spin asymmetry in the ep → eπ⁺n reaction. This represents the only existing measurement for this observable. The reaction is identified detecting the scattered electron and the emitted pion and using the missing mass technique to identify the neutron. The asymmetry is evaluated as a function of the four-momentum transfer Q², the invariant mass W and the pion center of mass angle θ*. These are in fact the variables that determine the transition amplitudes for the process. The W range of this measurement varies from the pion threshold to a maximum value of 1.8 GeV, exploring the full resonance region. The results obtained with this analysis in the evaluation of the spin asymmetry are presented. The outline of the thesis can be summarized as follows. The first chapter describes the physics motivation that are at the basis of this experiment. The second and third chapters illustrate the design of the CLAS detector and the polarized target. The fourth chapter gives a description of the event reconstruction and to the event selection while the analysis procedure is described in chapter five. Chapter six discusses the results of this measurement, including the evaluation of the systematic uncertainty and the comparison with a physics model.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 824907
• Report Number(s): JLAB-PHY-00-70; DOE/ER/40150-2753; TRN: US0402243
• Resource Relation: Other Information: TH: Thesis; Thesis information not provided; PBD: 1 Dec 2000
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMMETRY
DESIGN
ELECTRONS
ELECTROPRODUCTION
EVALUATION
MISSING MASS
PHYSICS
PIONS
POLARIZED TARGETS
RESONANCE
SPIN
TRANSITION AMPLITUDES