Date:
Mon, 30/05/201614:45-15:45
Location:
The large seminar room of the Physics building, Weizmann Institute of Science
Lecturer: Mr. Moshe Friedman
(for the E08-007 Collaboration)
Affiliation: Racah Institute of Physics,
The Hebrew University of Jerusalem
Abstract:
The proton electric and magnetic form factors
are basic characteristics of the proton, and can
be associated with the Fourier transforms of the
charge and magnetic current densities in the
non-relativistic limit. Although QCD can make
rigorous predictions when the four-momentum
transfer squared, Q2, is very large, in the non-
perturbative regime this task is too difficult, and
several phenomenological models attempt to
make predictions in this domain. Measurements
of the proton form factors were traditionally
based on cross section measurements using the
Rosenbluth separation method to extract the
electric and magnetic form factors. In this
method, the magnetic form factor is suppressed
as Q2 decreases, and precise data at very low
Q2 is not available. During the last two decades,
scattering experiments with polarized beams
and targets have been used for precise
measurements of the proton form factors at
much lower Q2 . The second part of experiment
E08-007 was dedicated to measure the ratio
between the proton form factors at 0.01 < Q2 <
0.08 GeV2, lower than ever achieved, by using
the double-spin asymmetry technique. The
experiment was conducted during the spring of
2012 at Hall A of the Thomas Jefferson National
Accelerator Facility, using a 1-2 GeV polarized
electron beam, scattering off a polarized solid
ammonia target. Data analysis is currently in
final stages. Recently, inconsistencies between
different measurements of the proton radius
have prompted intense theoretical and
experimental activities to resolve the
discrepancy. This experiment might improve
our understanding of this problem. In this talk, I
will describe the experimental system, the main
challenges in the data analysis, and present
preliminary results for the asymmetries and
their uncertainties.
Additional details of the upcoming Israeli
Joint Nuclear Physics' Seminars can be
found on the following link.
(for the E08-007 Collaboration)
Affiliation: Racah Institute of Physics,
The Hebrew University of Jerusalem
Abstract:
The proton electric and magnetic form factors
are basic characteristics of the proton, and can
be associated with the Fourier transforms of the
charge and magnetic current densities in the
non-relativistic limit. Although QCD can make
rigorous predictions when the four-momentum
transfer squared, Q2, is very large, in the non-
perturbative regime this task is too difficult, and
several phenomenological models attempt to
make predictions in this domain. Measurements
of the proton form factors were traditionally
based on cross section measurements using the
Rosenbluth separation method to extract the
electric and magnetic form factors. In this
method, the magnetic form factor is suppressed
as Q2 decreases, and precise data at very low
Q2 is not available. During the last two decades,
scattering experiments with polarized beams
and targets have been used for precise
measurements of the proton form factors at
much lower Q2 . The second part of experiment
E08-007 was dedicated to measure the ratio
between the proton form factors at 0.01 < Q2 <
0.08 GeV2, lower than ever achieved, by using
the double-spin asymmetry technique. The
experiment was conducted during the spring of
2012 at Hall A of the Thomas Jefferson National
Accelerator Facility, using a 1-2 GeV polarized
electron beam, scattering off a polarized solid
ammonia target. Data analysis is currently in
final stages. Recently, inconsistencies between
different measurements of the proton radius
have prompted intense theoretical and
experimental activities to resolve the
discrepancy. This experiment might improve
our understanding of this problem. In this talk, I
will describe the experimental system, the main
challenges in the data analysis, and present
preliminary results for the asymmetries and
their uncertainties.
Additional details of the upcoming Israeli
Joint Nuclear Physics' Seminars can be
found on the following link.