Welcome to the BGOOD experiment

Spokespersons: Paolo Levi Sandri (INFN Frascati), Thomas C. Jude (University of Bonn, Physikalisches Institut)

The BGOOD experiment at the ELSA electron accelerator facility in Bonn has been set up as a common project of an international collaboration with members of institutions from University of Bonn (Physikalisches Institut and HISKP); INFN Frascati; Messina University and INFN; Pavia University and INFN; Rome “Tor Vergata” and INFN; Torino University and INFN; Institute for Nuclear Research of NASU, Kyiv; Lamar University (Department of Physics).

The setup uniquely combines a central almost 4π acceptance BGO crystal calorimeter with a large aperture forward magnetic spectrometer providing excellent detection of both neutral and charged particles. Measurements are performed of non-strange and strange meson photoproduction reactions, in particular t-channel processes at low momentum transfer.

Physics

The BGOOD experiment is an experiment for meson photoproduction. The unique setup allows to investigate reactions directly at threshold and, in particular, t-channel processes at low momentum transfer.

Of special interest is the search for and investigation of unconventional baryonic and mesonic states in the (hidden-)strange quark sector. Unconventional here means a quark configuration beyond the conventional quark model; mesonic states with four quarks and baryonic states containing five quarks.

Such states have been observed in the charm quark sector. Understanding the nature of these states and whether they can be observed also in the sector of the lighter u, d, s quarks is currently one of the main topics at the BGOOD experiment.

Experimental Setup

The BGOOD experiment consists of three main parts: the Tagging system, the Central Detector and the Forward Spectrometer.

In the Tagging system the electron beam provided by ELSA is converted to a bremsstrahlung photon beam and the photon energy is determined. The Central Detector covers almost 4π and is particularly suited to detect photons, but can also detect charged particles. The Forward Spectrometer covers the polar angle range from 1° to 11°. Forward going charged particles are detected with high momentum resolution, and time-of-flight measurements allow for an excellent particle identification.