Latest results from meson photoproduction at ELSA and MAMI

Abstract

Abstract. Photoproduction of mesons plays a key role for the investigation of the excitation spectrum of the nucleon and thus for our understanding of the strong interaction in the nonperturbative regime. In this contribution we discuss recent results from the experiments at the tagged photon beams of the electron accelerators ELSA in Bonn and MAMI in Mainz. They include the measurement of cross sections and (double) polarization observables for single meson production and production of meson pairs off free protons as well as of quasifree nucleons bound in light nuclei (in particular the deuteron).

SPQR – Spectroscopy: Prospects, Questions & Results

“…1. Many of these new results from Bonn and Mainz are being presented at this conference [8,10]. More data are to come.…”

“…1 show that the N * 's and * 's from these two analyses have much in common, but there are some key differences that need to be resolved. The measurement of double polarization asymmetries, like the so called G-function with linearly polarized photons on a longitudinally polarized target open a unique window on to the higher partial waves [8,9]. They show that the need for important spin-3 components above 1.55 GeV, seen in the top right corner of at this conference [8,10].…”

Light Baryon Spectroscopy

“…The TAPS setup consisted of six detector blocks of BaF 2 crystals arranged around the target and one larger forward block. It provided energy, pulse-shape, time of flight and, together with the plastic scintillators in front of the crystals, charge information of the detected particles [122].…”