Speaker
Gilberto Ramalho
(LTFC, Universidade Cruzeiro do Sul)
Description
We present calculations of $\gamma^\ast N \to N^\ast$
transition form factors, where $N$ is the nucleon
and $N^\ast$ and $N^\ast$ is a nucleon resonance,
based on a covariant quark model.
At high photon virtualities (large $Q^2$)
it is expected that the valence quark degrees of freedom
dominate the contributions to the transition form factors.
In these conditions, the quark model estimates
can be compared with the available data,
particularly with the Jefferson Lab data
at intermediate and large momentum transfer ($Q^2 >2$ GeV$^2$).
The main focus is on the $\Delta(1232)3/2^+$,
$N(1440)1/2^+$, $N(1535)1/2^-$ and $N(1520)3/2^-$ resonances,
but the estimates for other higher mass resonances are also discussed.
Primary author
Gilberto Ramalho
(LTFC, Universidade Cruzeiro do Sul)
