Meson exchange currents in deuteron electrodisintegration and the nucleon axial vector form factor

Journal Article · Mon Sep 01 04:00:00 EDT 1975 · Ann. Phys. (N.Y.), v. 93, no. 1, pp. 276-334

DOI:https://doi.org/10.1016/0003-4916(75)90213-4· OSTI ID:4080856

Lock, J A; Foldy, L L

Double differential cross sections for deuteron electrodisintegration near threshold from back-scattered electrons were calculated for electron four- momentum transfer squares in the range 0 < or = $delta$$sup 2$ < or = 15 fm$sup - 2$ and for final n--p relative energies in the range 0 = or = E/sub rel/ < or = 15 MeV using the Reid hard-core parametrization of the n--p potential and considering the free nucleon or impulse process and various one-pion exchange processes. Particular attention was paid to the study of the form factors of the mesonic processes and to the dependence of the cross section on various n--p potentials. In particular, the cross section was found to be dominated by the impulse process for $delta$$sup 2$ = or = $sup 8$ fm$sup -2$ and by the catastrophic meson exchange process for $delta$$sup 2$ > or = 8 fm$sup -2$. Since in dispersion theories the catastrophic process is proportional to the isovector Dirac nucleon form factor F$sub 1$/sup V/($delta$$sup 2$) while in PCAC- current algebra theories it is proportional to the nucleon axial vector form factor F/sub A/(delta$sup 2$), a determination of the catastrophic form factor was undertaken. It was found that the experimental data was reasonably fitted by F/sub A/($delta$$sup 2$) = (1+delta$sup 2$/m/sub A/$sup 2$$)$$sup -2$ with m/sub A/ = 0.81 GeV. This value of m/sub A/ is within the range of values determined from neutrino scattering experiments. Further, the cross section was found to be relatively insensitive to the n--p potential employed, provided it exhibits repulsive core behavior for r less than about 0.5 fm. Finally, possible parametrizations of the off-shell contributions to the pion form factor and contributions to the cross section from scattering to the $sup 3$$S$$sub 1$--$sup 3$$D$$sub 1$ and l>0 final states were examined. (AIP)

• Research Organization: Case Western Reserve University, Cleveland, Ohio 44106
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-021379
• OSTI ID: 4080856
• Journal Information: Ann. Phys. (N.Y.), v. 93, no. 1, pp. 276-334, Journal Name: Ann. Phys. (N.Y.), v. 93, no. 1, pp. 276-334; ISSN APNYA
• Country of Publication: United States
• Language: English

Related Subjects

*ELECTRON-DEUTERON INTERACTIONS-- DIFFERENTIAL CROSS SECTIONS
641102*
BACKSCATTERING
ELECTRONS
FORM FACTORS
HARD-CORE POTENTIAL
N64220* --Physics (High Energy)--Particle Interactions &amp; Properties (Theoretical)--Electromagnetic
OPE MODEL
PCAC THEORY
REID POTENTIAL
WAVE FUNCTIONS