Commissioning the Belle II VerteX Detector (VXD), at KEK Center, Japan, With Comic Rays

Belle & BaBar had been cited as main contributors to the 2008 Nobel Prize on elementary particles symmetries flourished in 1973 by a paper explaining the theory of CP violation phenomenon in the standard model. The CP violation phenomenon is important in explaining the dominance of matter in the universe & complete absence of anti-matter. KEKB collider is being upgraded to a collider called SuperKEKB with 40X more luminosity. At that luminosity envisaged for SuperKEKB, the BelleII sub-detectors close to the beam pipe are faced with extremely high hit rates, caused by beam-related background hence Belle is upgraded to BelleII detector to cope with the additional high background rate.

Belle VXD is used to reconstruct the decay vertices of the B-mesons produced at e+e- collisions needed to study CP violation. VXD was mainly made by silicon strips detectors that are assembled in 4 layers of silicon detector modules to form SVD. In BelleII VXD is upgraded with what called PXD made of 2 more layers of pixel modules, made of DEPFET sensor which is the best candidate due to its low leakage current hence well suitable to cope with the high radiation environment at~2cm from the SuperKEKB Interaction Point.

We discuss the cosmic rays results, especially at the SVD & PXD alignment level.