https://doi.org/10.1140/epja/i2008-10690-6
Regular Article - Theoretical Physics
Electromagnetic form factor via Bethe-Salpeter amplitude in Minkowski space
1
Laboratoire de Physique Subatomique et Cosmologie, 53 avenue des Martyrs, 38026, Grenoble, France
2
Lebedev Physical Institute, Leninsky Prospekt 53, 119991, Moscow, Russia
Received:
22
September
2008
Revised:
10
November
2008
Published online:
11
December
2008
For a relativistic system of two scalar particles, we find the Bethe-Salpeter amplitude in Minkowski space and use it to compute the electromagnetic form factor. The comparison with Euclidean space calculation shows that the Wick rotation in the form factor integral induces errors which increase with the momentum transfer Q2. At JLab domain (Q 2 = 10 GeV^2/c2), they are about 30%. Static approximation results in an additional and more significant error. On the contrary, the form factor calculated in light-front dynamics is almost indistinguishable from the Minkowski space one.
PACS: 11.10.St Bound and unstable states; Bethe-Salpeter equations – / 13.40.Gp Electromagnetic form factors – / 21.45.-v Few-body systems –
© SIF, Springer-Verlag Berlin Heidelberg, 2009
