608 research outputs found
Phenomenology of the Deuteron Electromagnetic Form Factors
A rigorous extraction of the deuteron charge form factors from tensor
polarization data in elastic electron-deuteron scattering, at given values of
the 4-momentum transfer, is presented. Then the world data for elastic
electron-deuteron scattering is used to parameterize, in three different ways,
the three electromagnetic form factors of the deuteron in the 4-momentum
transfer range 0-7 fm^-1. This procedure is made possible with the advent of
recent polarization measurements. The parameterizations allow a
phenomenological characterization of the deuteron electromagnetic structure.
They can be used to remove ambiguities in the form factors extraction from
future polarization data.Comment: 18 pages (LaTeX), 2 figures Feb. 25: minor changes of content and in
Table
A Measurement of the Electric Form Factor of the Neutron through at (GeV/c)
We report the first measurement of the neutron electric form factor
via using a solid polarized target. was
determined from the beam-target asymmetry in the scattering of longitudinally
polarized electrons from polarized deuterated ammonia, ND. The
measurement was performed in Hall C at Thomas Jefferson National Accelerator
Facility (TJNAF) in quasi free kinematics with the target polarization
perpendicular to the momentum transfer. The electrons were detected in a
magnetic spectrometer in coincidence with neutrons in a large solid angle
segmented detector. We find at (GeV/c).Comment: Latex2e 5 pages, 3 figure
Measurements of electron-proton elastic cross sections for
We report on precision measurements of the elastic cross section for
electron-proton scattering performed in Hall C at Jefferson Lab. The
measurements were made at 28 unique kinematic settings covering a range in
momentum transfer of 0.4 5.5 . These measurements
represent a significant contribution to the world's cross section data set in
the range where a large discrepancy currently exists between the ratio of
electric to magnetic proton form factors extracted from previous cross section
measurements and that recently measured via polarization transfer in Hall A at
Jefferson Lab.Comment: 17 pages, 18 figures; text added, some figures replace
Value of formalisation for women entrepreneurs in developing contexts: a review and research agenda
Formalisation is constantly being proposed as of great benefit to business expansion and success. This claim however has not been previously tested through a review of the empirical evidence, especially in relation to the large number of women in the developing world that operate in the informal economy. Therefore, our aim in this review is to systematise the current empirical evidence on gender, the informal economy and formalisation using a narrative synthesis of 76 papers. The papers were analysed along three main analytical themes â identity, institutions and, constraints and preferences, highlighting their conceptualisation in studies of different academic disciplines â economics, sociology, entrepreneurship and development. The review calls for more accurate accounts of formalisation decisions by widening the lens through which formalisations decisions are conceptualised. These should take account of the rich contextual and temporal dimensions central to these decisions, and recognise that gender alone is not a sufficient factor in explaining womenâs choices in the informal economy. The review also highlights limitations in relation to the limited conceptual and empirical evidence on which development priorities such as formalisation are set. We propose a research agenda that centres on the need for conceptual frameworks that are more sensitive towards the multi-dimensional contexts of womenâs choices
Determination of the pion charge form factor for Q^2=0.60-1.60 GeV^2
The data analysis for the reaction H(e,e' pi^+)n, which was used to determine
values for the charged pion form factor Fpi for values of Q^2=0.6-1.6 GeV^2,
has been repeated with careful inspection of all steps and special attention to
systematic uncertainties. Also the method used to extract Fpi from the measured
longitudinal cross section was critically reconsidered. Final values for the
separated longitudinal and transverse cross sections and the extracted values
of Fpi are presented.Comment: 11 pages, 6 figure
Measurement of the Charged Pion Electromagnetic Form Factor
Separated longitudinal and transverse structure functions for the reaction
1H(e,eprime pi+)n were measured in the momentum transfer region Q2=0.6-1.6
(GeV/c)**2 at a value of the invariant mass W=1.95 GeV. New values for the pion
charge form factor were extracted from the longitudinal cross section by using
a recently developed Regge model. The results indicate that the pion form
factor in this region is larger than previously assumed and is consistent with
a monopole parameterization fitted to very low Q2 elastic data.Comment: 5 pages, 3 figure
Measurements of Deuteron Photodisintegration up to 4.0 GeV
The first measurements of the differential cross section for the d(gamma,p)n
reaction up to 4.0 GeV were performed at Continuous Electron Beam Accelerator
Facility (CEBAF) at Jefferson Lab. We report the cross sections at the proton
center-of-mass angles of 36, 52, 69 and 89 degrees. These results are in
reasonable agreement with previous measurements at lower energy. The 89 and 69
degree data show constituent-counting-rule behavior up to 4.0 GeV photon
energy. The 36 and 52 degree data disagree with the counting rule behavior. The
quantum chromodynamics (QCD) model of nuclear reactions involving reduced
amplitudes disagrees with the present data.Comment: 5 pages (REVTeX), 1 figure (postscript
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