Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2011-05-31
Physics
High Energy Physics
High Energy Physics - Phenomenology
14 pages, 12 figures
Scientific paper
The transverse charge density in a fast-moving nucleon is represented as a dispersion integral of the imaginary part of the Dirac form factor in the timelike region (spectral function). At a given transverse distance b the integration effectively extends over energies in a range sqrt{t} ~< 1/b, with exponential suppression of larger values. The transverse charge density at peripheral distances thus acts as a low-pass filter for the spectral function and allows one to select energy regions dominated by specific t-channel states, corresponding to definite exchange mechanisms in the spacelike form factor. We show that distances b ~ 0.5 - 1.5 fm in the isovector density are maximally sensitive to the rho meson region, with only a ~10% contribution from higher-mass states. Soft-pion exchange governed by chiral dynamics becomes relevant only at larger distances. In the isoscalar density higher-mass states beyond the omega are comparatively more important. The dispersion approach suggests that the positive transverse charge density in the neutron at b ~ 1 fm, found previously in a Fourier analysis of spacelike form factor data, could serve as a sensitive test of the the isoscalar strength in the ~1 GeV mass region. In terms of partonic structure, the transverse densities in the vector meson region b ~ 1 fm support an approximate mean-field picture of the motion of valence quarks in the nucleon.
Miller Gary A.
Strikman Mark
Weiss Carsten
No associations
LandOfFree
Realizing vector meson dominance with transverse charge densities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Realizing vector meson dominance with transverse charge densities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Realizing vector meson dominance with transverse charge densities will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-339225