Measurement of helicity dependence of single π⁰ photoproduction on deuteron

University of Mainz, Germany

^* e-mail: fecividi@uni-mainz.de

Published online: 1 February 2019

Abstract

The study of the properties of the baryon resonances gives essential constraints on models for nucleon structure. Pion-photoproduction is a powerful tool to excite the nucleon to an intermediate resonant state and, in combination with polarised beams/targets, plays an important role in the investigation of the nucleon resonances. Data for polarisation observables accessible using a polarised photon beam and/or polarised nucleon targets are scarce in many channels, especially in those involving a neutron target. A systematic measurement is performed at the Mainz facility by the A2@MAMI collaboration. This talk will focus on the experiment performed at the Mainz Microtron, using a circularly polarised photon beam and a longitudinally polarised deuteron target, in conjunction with the large acceptance Crystal Ball/TAPS detection setup. An overview of the status of the experiment will be given, together with the preliminary results of polarised cross section from deuteron and of the double polarization observable E for the single π⁰ photoproduction reaction from the quasi-free proton and quasi-free neutron.