Jun 5 – 9, 2023
Genova, Italy
Europe/Rome timezone

Timelike Compton Scattering on a polarised target with CLAS12 at Jefferson Lab

Jun 9, 2023, 10:00 AM
DAD - Room 1B (Genova, Italy)

DAD - Room 1B

Genova, Italy

Contributed QCD and hadron structure QCD and hadron structure


Ms Kayleigh Gates (University of Glasgow, United Kingdom)


Time-Like Compton Scattering (TCS) is a hard, exclusive scattering process, in which a real photon scatters from a target nucleon, producing a virtual
(timelike) photon, which couples to a lepton pair in the final state [1].
TCS, via cross section and asymmetry observables, gives access to Gener-
alised Parton Distributions (GPDs), through which we can develop a tomo-
graphic mapping of nucleon structure, and access information pertaining to
the mechanical properties of hadrons, such as shear forces and pressure dis-
tributions. The first published result of TCS in 2021 [2] was measured on an
unpolarised hydrogen target. This work seeks to present another first measure-
ment by performing the analysis on a longitudinally polarised target, from which
Target Spin Asymmetries (TSA) and Double Spin Asymmetries (DSA) can be
measured, allowing access to the GPDs $H$ and $\tilde{H}$ .
To this end, I present a preliminary extraction of a TCS signal from recent
data taking at Jefferson Lab during Run Group C, using quasi-real photons
from the 10.6 GeV electron beam and the CLAS12 detector.

[1] E.R. Berger, M. Diehl, and B. Pire. Timelike compton scattering: exclu-
sive photoproduction of lepton pairs. The European Physical Journal C,
23(4):675–689, apr 2002.
[2] P. Chatagnon et al. First measurement of timelike compton scattering. Phys. Rev. Lett., 127:262501, Dec 2021.

Primary author

Ms Kayleigh Gates (University of Glasgow, United Kingdom)


Dr Daria Sokhan (University of Glasgow, United Kingdom. IRFU, CEA Université Paris-Saclay, 91191 Gif-sur-Yvette, France) Dr Rachel Montgomery (University of Glasgow, United Kingdom)

Presentation materials