# WASA-at-COSY

WASA, a spectrometer with large solid angle acceptance, has been operated at the internal COSY beam from 2006 to 2015. It was used to investigate the production and decay of light mesons and to study symmetries and symmetry breaking patterns.

The operation of WASA at COSY has been a joined effort of whole IKP together with international collaborators. The focus of IKP-2 with respect to the maintenance and operation was the central detector with the superconducting solenoid, the straw-tube tracker, the plastic scintillator barrel and the electromagnetic calorimeter together with the straw-tube tracker in the forward detector. In addition, the IKP-2 was - in close collaboration with ZEA-2 - active in the field of data acquisition, read-out electronics and computing resources.

The major focus within the wide-spread physics program of WASA in IKP-2 is the investigation of the Charge Symmetry Breaking in the dd → 4He π0 reaction. This reaction is forbidden by isospin symmetry in general and by charge symmetry in particular. Any non-vanishing signal is an experimental probe for hadronic effects caused by the mass difference of the up and the down quark.

# Local contact persons in IKP-2:



Calorimeter, electronics, dd → 4He π0

Dr. Volker Hejny



Straw-tube detectors

Dr. Henner Ohm



Supraconducting solenoid

Dr. Ralf Engels