1. Samara State University, Samara, Russia
XXXIII INTERNATIONAL
CONFERENCE ON HIGH
ENERGY PHYSICS
ICHEP'06 Moscow,
26 July – 2 August 2006
A.F. Krutov
Samara State University, Samara, Russia
V.E. Troitsky
D.V. Skobeltsyn Institutе of Nuclear Physics
Moscow State University, Moscow, Russia
Relativistic calculation of the neutron charge
form factor from the JLab deuteron data

2. Electromagnetic structure of the nucleons
Motivation:
Electromagnetic structure of the nucleons , ,
the momentum transfer.
is still known rather poorly.
Difficulties:
- The lack of a free-neutron target and extraction of the neutron charge form factor from data for composite nuclei
Необходимость рел...
- Results depend crucially on the model for NN-interaction
- Relativistic effects
Meson exchange currents
- etс.

3. The present report:
The neutron charge form factor is extracted from
the experimental data on the deuteron charge form factor
obtained through polarization experiment in the JLab.

4. Modern relativistic calculations of the deuteron structure in
the nucleon model are based on the two main classes of approaches:
The field-theoretical approaches
- Bethe-Salpeter equation
- quasipotential approaches
Relativistic Hamiltonian dynamics (RHD)
- instant form
- light-front form
- point form
Our approach:
Instant form of the relativistic
Hamiltonian dynamics (RHD)
A.F. Krutov, V.E. Troitsky, Phys.Rev.C 65 (2002)
A.F. Krutov, V.E. Troitsky, Phys.Rev.C 68 (2003)
A.F. Krutov, V.E. Troitsky, Theor.Math.Phys. 143 (2005) 704

5. The main features of our approach:
the method of construction of the matrix elements of
the electroweak current operator
the electroweak current matrix satisfies the relativistic
covariance conditions
the electromagnetic current satisfies the conservation law
The relativistic impulse approximation in our
approach:
the Lorentz covariance of the currrent is ensured
the electromagnetic current consrvation law is ensured

6. The deuteron charge form factor in our approach in
the relativistic impulse approximation:

7. The charge form factor of the neutron:

8. Deuteron wave functions in sense of RHD are
solution of eigenvalue problem for complete set of commuting operators:
Eigenvalue problem for
It is Schrödinger equation within a second order on deuteron binding energy:
Normalization:

9. The problem of choosing the model deuteron wave functions
Paris potential model
Nijmegen I
Nijmegen II
Nijmegen 93
charge-dependent Bonn model
Muzafarov-Troitsky (MT)-wave function from the
potentialless approach to the inverse scattering problem

10. for polarized ed-scattering depends weakly on
the nucleon form factors

11. Relativistic corrections to the

12. as the test for deuteron wave functions

13. Function
for the elastic ed-scattering

14. The important features of the MT-wave functions:
no form of NN-interaction Hamiltonian is used
they are given by dispersion-type integral in terms of
experimental phase shifts and mixing parameter
the phase shifts at large energy are described by Regge analysis
they were obtained from quite general assumptions about
analytical properties of quantum amplitudes (Mandelstam
representation for the deuteron electrodesintegration amplitude)
they have not fitting parameters

15. The problem of the meson exchange currents (MEC)
Siegert theorem [A.J.F.Siegert, Phys.Rev. 52, 787 (1937)]
if the electromagnetic current satisfies the consrvation law
if the dynamics of the two-particle systems is nonrelativistic
(the Schrodinger equation, potential)
then the charge density of the exchange current is zero
(the contribution of MEC to the charge and quadrupole
deuteron form factors is zero)

16. The experimental values and the result of fitting for
the neutron charge form factor

17. The result of fitting for the neutron charge form factor

18. The present fitting of the neutron charge form factor will be
used in the neutrino scattering experiments in Fermilab
[ D.Drakoulakos et al., Proposal to Perform a High-Statistic
Neutrino Scattering Experiment Using a Fine-grained
Detector in the NuMI Beam, hep-ex/ ]

19. Conclusions:
the new procedure was suggested for extraction of the
neutron charge form factor from charge form factor
of deuteron
12 new points for charge neutron form factor were obtained
the fitting was performed for 36 values of neutron charge
form factor including our points