The ^2H(e,e'p)n Reaction at High Four-Momentum Transfer
This dissertation presents the highest four-momentum transfer, Q^2,quasielastic (x_Bj = 1) results from Experiment E01-020 which systematically explored the 2He(e,e'p)n reaction ("Electro-disintegration" of the deuteron) at three different four-momentum transfers, Q^2 = 0.8, 2.1, and 3.5 GeV^2 and missing momenta, P_miss = 0, 100, 200, 300, 400, and 500 GeV including separations of the longitudinal-transverse interference response function, R_LT, and extractoin of the longitudinal-transverse asymmetry, A_LT. This systematic approach will help to understand the reaction mechanism and the deuteron structure down to the short range part of the nucleon-nucleon interaction which is one of the fundamental missions of nuclear physics. By studying the very short distance structure of the deuteron, one may also determine whether or to what extent the description of nuclei in terms of nucleon/meson degrees of freedom must be supplemented by inclusion of explicit quark effects. The unique combination of energy, current, duty factor, and control of systematics for Hall A at Jefferson Lab made Jefferson Lab the only facility in the world where these systematic studies of the deuteron can be undertaken. This is especially true when we want to understand the short range structure of the deuteron where high energies and high luminosity/duty factor are needed. All these features of Jefferson Lab allow us to examine large missing momenta (short range scales) at kinematics where the effects of final state interactions (FSI), meson exchange currents (MEC), and isobar currents (IC) are minimal, making the extraction of the deuteron structure less model-dependent. Jefferson Lab also provides the kinematical flexibility to perform the separation of R_LT over a broad range of missing momenta and momentum transfers. Experiment E01-020 use the standard Hall A equipment in coincidence configuration in addition to the cryogenic target system. The low and middle Q^2 kinematics were completed in June 2002 and the high Q^2 kinematics were completed in November 2002. Before the start of the experiment many preparations were made to assure the quality of the collected data. Approximately two Terabytes of data were collected by the end of the experiment. The cross section results in this dissertation show clearly the effect of final state interactions between the two final state nucleons. The cross section ratio to the Laget PWBA+FSI calculation has a wiggle at P_miss ~ 300 MeV. It is yet to be seen whether this is merely due to the lack of MEC and IC in the present theoretical calculation. However, a similar feature was observed in a previous Hall A experiment. Further, discrepancies at very low P_miss cast some doubt on neutron form factor measurements using the deuteron as target. This study will add to the already growing body of systematic data for the ^2H(e,e'p)n reaction to better understand the N N short range and to provide vital input for heavier nuclei.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE - Office of Energy Research (ER)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 917020
- Report Number(s):
- JLAB-PHY-06-621; DOE/ER/40150-4352; TRN: US0804411
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BOSON-EXCHANGE MODELS
CROSS SECTIONS
DEGREES OF FREEDOM
FINAL-STATE INTERACTIONS
FORM FACTORS
FOUR MOMENTUM TRANSFER
MOMENTUM TRANSFER
NUCLEAR PHYSICS
NUCLEON-NUCLEON INTERACTIONS
REACTION KINETICS
RESPONSE FUNCTIONS