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Title: Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS

Abstract

The ep {yields} e'pi{sup +}n reaction was studied in the first and second nucleon resonance regions in the 0.25 GeV{sup 2} < Q{sup 2} < 0.65 GeV{sup 2} range using the CLAS detector at Thomas Jefferson National Accelerator Facility. For the first time the absolute cross sections were measured covering nearly the full angular range in the hadronic center-of-mass frame. The structure functions {sigma}{sub TL}, {sigma}{sub TT} and the linear combination {sigma}{sub T} + {epsilon}{sigma}{sub L} were extracted by fitting the {phi}-dependence of the measured cross sections, and were compared to the MAID and Sato-Lee models.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
875583
Report Number(s):
JLAB-PHY-06-06; DOE/ER/40150-3679; nucl-ex/0601007
TRN: US0601148
DOE Contract Number:
AC05-84ER40150
Resource Type:
Journal Article
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CEBAF ACCELERATOR; CROSS SECTIONS; ELECTROPRODUCTION; NUCLEONS; PROTONS; RESONANCE; STRUCTURE FUNCTIONS

Citation Formats

H. Egiyan, I.G. Aznauryan, V.D. Burkert, K.A. Griffioen, K. Joo, R. Minehart, and L.C. Smith. Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS. United States: N. p., 2006. Web.
H. Egiyan, I.G. Aznauryan, V.D. Burkert, K.A. Griffioen, K. Joo, R. Minehart, & L.C. Smith. Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS. United States.
H. Egiyan, I.G. Aznauryan, V.D. Burkert, K.A. Griffioen, K. Joo, R. Minehart, and L.C. Smith. Thu . "Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS". United States. doi:. https://www.osti.gov/servlets/purl/875583.
@article{osti_875583,
title = {Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS},
author = {H. Egiyan and I.G. Aznauryan and V.D. Burkert and K.A. Griffioen and K. Joo and R. Minehart and L.C. Smith},
abstractNote = {The ep {yields} e'pi{sup +}n reaction was studied in the first and second nucleon resonance regions in the 0.25 GeV{sup 2} < Q{sup 2} < 0.65 GeV{sup 2} range using the CLAS detector at Thomas Jefferson National Accelerator Facility. For the first time the absolute cross sections were measured covering nearly the full angular range in the hadronic center-of-mass frame. The structure functions {sigma}{sub TL}, {sigma}{sub TT} and the linear combination {sigma}{sub T} + {epsilon}{sigma}{sub L} were extracted by fitting the {phi}-dependence of the measured cross sections, and were compared to the MAID and Sato-Lee models.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 05 00:00:00 EST 2006},
month = {Thu Jan 05 00:00:00 EST 2006}
}
  • The ep{yields}e{sup '}{pi}{sup +}n reaction was studied in the first and second nucleon resonance regions in the 0.25 GeV{sup 2}<Q{sup 2}<0.65 GeV{sup 2} range by use of the CLAS detector at Thomas Jefferson National Accelerator Facility. For the first time, to our knowledge, the absolute cross sections were measured, covering nearly the full angular range in the hadronic center-of-mass frame. We extracted the structure functions {sigma}{sub TL},{sigma}{sub TT}, and the linear combination {sigma}{sub T}+{epsilon}{sigma}{sub L} by fitting the {phi} dependence of the measured cross sections and compared them with the MAID and Sato-Lee models.
  • The study of single pion electroproduction can provide valuable information on the structure of the nucleon and its excited states. Although these reactions have been studied for decades, never has the n π + channel been measured over the complete phase space of the reaction. The CEBAF Large Acceptance Spectrometer (CLAS) located in Hall B of Jefferson Lab is well-suited for conducting these measurements. The CLAS data were taken using a 1.515 GeV electron beam incident on a liquid H 2 target. The cross sections have been extracted, and their phi-dependence has been fit to obtain the sigma TT, sigmamore » TL and the sigma T + epsilon sigma L linear combination of the structure functions. An analysis program based on the Mainz unitary isobar model was used to analyze the experimental data from the π + channel only. The resonant amplitudes for P 33(1232), S L(1535) and D{sub 13}(1520) were obtained from the fit.« less
  • We present a measurement of the induced proton polarization P{sub n} in {pi}{sup 0} electroproduction on the proton around the {Delta} resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of W=1231 MeV and Q{sup 2}=0.126 GeV{sup 2}/c{sup 2}, respectively. We measured a large induced polarization, P{sub n}={minus}0.397{plus_minus}0.055{plus_minus}0.009. The data suggest that the scalar background is larger than expected from a recent effective Hamiltonian model. {copyright} {ital 1998} {ital The American Physical Society}
  • This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep{yields}e{sup '}p{pi}{sup +}{pi}{sup -}. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2<Q{sup 2}<0.6 GeV{sup 2} and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q{sup 2} covered by the measurements. A phenomenological analysis of the data allowed us tomore » establish the most significant mechanisms contributing to the reaction. The nonresonant mechanisms account for a major part of cross sections. However, we find sensitivity to s-channel excitations of low-mass nucleon resonances, especially to the N(1440)P{sub 11} and N(1520)D{sub 13} states in kinematic dependencies of the one-fold differential cross sections.« less