# Light Cone 2022 Online: Physics of Hadrons on the Light Front

Sep 19 – 23, 2022
ONLINE (ZOOM)
GMT timezone

## Virtual Compton scattering on ${}^4$He: Rosenbluth formula

Sep 22, 2022, 3:15 PM
30m
ONLINE (ZOOM)

### Speaker

Ben Bakker (VU, Amsterdam)

### Description

In the present study, the phenomenology of deeply virtual Compton scattering (DVCS) is considered. It is a well-known fact that a charged spin zero hadron has five Compton form factors (CFFs), all of which contribute to the DVCS ampli- tude if the absorbed and emitted photons are virtual. If the emitted photon is real, the number of CFFs that contribute is reduced to three. This analysis is relevant for experiments on DVCS on 4He.
It is important to be aware of the fact that the CFFs, unlike Generalized Parton Distributions, are Lorentz scalars. Therefore they can be studied in any kinematics. The work presented here analyses the behaviour of the CFFs for large Q. The contributions to the DVCS amplitude of the CFFs that are suppressed by powers of Q appear to be kinematically enhanced. Moreover, for medium values of Q, less than the mass of the 4He nucleus, for instance attainable at CEBAF, target mass effects are also important. The Rosenbluth-type of representation of the cross sections is presented. As a
benchmark, the beam-spin asymmetry at tree level is presented.

### Primary author

Ben Bakker (VU, Amsterdam)

### Presentation materials

 Ben Bakker.mp4 LC2022-Ben.pdf