Exclusively produced rho^0 asymmetries on the deuteron and future GPD measurements at COMPASS

TL;DR

This paper reports on the measurement of rho^0 meson production asymmetries on deuteron targets at COMPASS, highlighting initial results and future plans for probing nucleon structure through GPDs using upgraded experimental setups.

Contribution

It presents the first results of rho^0 transverse target spin asymmetries on deuterons at COMPASS and discusses future GPD measurements with upgraded detectors.

Findings

Measured rho^0 asymmetries on deuteron targets.

Demonstrated feasibility of future GPD measurements at COMPASS.

Outlined detector upgrades and simulation results.

Abstract

Generalized parton distributions (GPDs) provide a new and powerful framework for a complete description of the nucleon structure. They can provide a three-dimensional picture of how the quarks and gluons form a nucleon. GPDs can be probed experimentally in hard exclusive meson production or deeply virtual Compton scattering (DVCS). The COMPASS experiment at CERN is a unique place to study these reactions. At COMPASS, a high energy polarized positive or negative muon beam is scattered off a polarized or unpolarized fixed target. First results for exclusive rho^0 meson production are shown. The transverse target spin asymmetry for exclusively produced rho^0 on a transversely polarized deuteron target has been measured. Prospects for future measurements of DVCS and exclusive meson production at COMPASS will be shown. The experiment will use the existing COMPASS spectrometer with a new target, a new recoil detector and extended calorimetry. Simulations for different models and a test of the recoil detector have been performed.