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Old Dominion University

Theses/Dissertations

Physics

Pions

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Full-Text Articles in Physical Sciences and Mathematics

Single And Double Spin Asymmetries For Pion Electro-Production From The Deuteron In The Resonance Region, Sharon L. Careccia Apr 2012

Single And Double Spin Asymmetries For Pion Electro-Production From The Deuteron In The Resonance Region, Sharon L. Careccia

Physics Theses & Dissertations

The single and double spin asymmetries At and Aet have been measured in π- electro-production off the deuteron using a longitudinally polarized electron beam and a polarized ND3 target. The electron beam was polarized using a strained GaAs cathode and the target was polarized using Dynamic Nuclear Polarization. The data were collected at beam energies of 1.6, 1.7, 2.5 and 4.2 GeV in Hall B at Jefferson Lab in the spring of 2001. The final state particles were detected in the CEBAF Large Acceptance Spectrometer (CLAS). The d(e,e'π-p)p exclusive channel was identified using the missing mass …


Measurement Of The Gπnn(T) Form Factor, Kelly Gene Vansyoc Jul 2001

Measurement Of The Gπnn(T) Form Factor, Kelly Gene Vansyoc

Physics Theses & Dissertations

Cross sections were measured for the reaction 1H(e, e′π+) n at the energy W = 1.95 GeV and momentum transfer Q2 = 0.6 (GeV/c)2. At this W and Q2, the longitudinal cross section is dominated by t-channel production, giving a unique opportunity to examine the strong coupling form factor gπNN(t). The measured cross sections were separated using a method similar to a Rosenbluth separation. For the extraction of gπNN(t), the Actor and Körner model [42] and a parameterization of the MAID2000 …


Phenomenological Description Of Double-Pion Photoproduction, Andry M. Rakotovao Jul 2000

Phenomenological Description Of Double-Pion Photoproduction, Andry M. Rakotovao

Physics Theses & Dissertations

Double pion photoproduction off proton targets is studied, in the framework of an Effective Lagrangian approach at tree level, based on the coupling of photons and pions to nucleons and resonances. We consider N, Δ(1232), N(1440), N(1520) and N(1535) as intermediate baryonic states and ρ-meson as the intermediate 2π resonance. The general form of the amplitude is presented and total cross sections of the γp → π+π− p, γp → π0π0p and γp → π +π0n processes are evaluated up to Eγ …


Pion Absorption On Polarized Lithium-7 At 165 Mev, Thomas A. Greco Apr 1996

Pion Absorption On Polarized Lithium-7 At 165 Mev, Thomas A. Greco

Physics Theses & Dissertations

Pion absorption is not well understood. Cross section data alone does not provide a complete description since the cross section tends to be sensitive only to the spin-independent terms in the transition amplitude. Polarization observables are thus necessary to complete the picture. In this experiment, analyzing powers for the reaction 7→Li(π+,pp)5He at Tπ = 165 MeV were measured at the Paul Scherrer Institut, Switzerland. The emitted protons were detected with the SUSI spectrometer at 38° in coincidence with an array of five scintillator telescopes centered around the quasi-free angle for absorption on a nucleon …


The Study Of Pion Absorption On -4he At 355 Mev/C With Lads (Large Acceptance Detector System), Thomas A. Dooling Jul 1995

The Study Of Pion Absorption On -4he At 355 Mev/C With Lads (Large Acceptance Detector System), Thomas A. Dooling

Physics Theses & Dissertations

The medium and long range part of the nucleon-nucleon interaction can be described within the framework of pion exchange. In order to understand this fundamental interaction, it is therefore important to study the interaction of pions with nucleons and nuclei, which can either be elastic or inelastic scattering or absorption. Whereas the elastic and inelastic channels can be well described by different models, our understanding of pion absorption is still rather poor. There are still a lot of open questions, for instance on the strength of three and more nucleon absorption and the role of initial and final state interactions. …