Study of nuclear media effects in meson photoproduction

A Lapik,N Rudnev,V Lisin,A Polonski,V Nedorezov

doi:10.1051/epjconf/201920401005

Abstract

In addition to the current BGO-OD experimental program we propose to study nuclear media effects in photoproduction of mesons using a new experimental method based on measuring a recoil nucleon as a tagger of the selected partial channel. The principal goal is to learn how unstable mesons (πo, π+, π−, η, ρ, ω, etc.) interact with nuclear media. This approach continues previous GRAAL experiments to study nuclear excitation dynamics, including multifragmentation of nuclei by intermediate energy photons.

Highlights

Current BGO-OD experiments are devoted mainly to strangeness photoproduction at intermediate energies [1]
We studied the proton detection efficiency in the Barrel, i.e. the ratio of events when the proton was detected on the targets
The future BGO-OD experiment using the recoil nucleon is a tagger of the partial meson photoproduction interesting in different aspects of research in dependence of multiplicity on recoil nucleons

Summary

Introduction

Current BGO-OD experiments are devoted mainly to strangeness photoproduction at intermediate energies [1]. This experiment at the ELSA accelerator facility uses the energy tagged bremsstrahlung photon beam to investigate the excitation spectrum of the nucleon. The setup (see Fig. 1) consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. The high momentum resolution at forward angles covers the kinematic region. Preliminary BGO-OD experimental results [1] (see Fig. 2) demonstrate a high momentum resolution of the recoil nucleons from kaon meson production. A principal improvement as compared with GRAAL has been obtained due to the magnetic spectrometer placed downstream of the target to distinguish charged mesons, protons, deuterons and other charged products. The BGO-OD facility is appropriate to study the nuclear excitation dynamics using the recoils as taggers

Description of the new method and experimental requirements

World results available for comparison

Conclusion