Impact of the Belle II pixel detector on the analysis of CP-violation

Abstract

The new asymmetric electron positron collider SuperKEKB in Tsukuba, Japan, is currently being commissioned. With a design luminosity of 8 · 1035 cm−2 s−1, leading ultimately to an integrated luminosity of about 50 ab−1, it will overtake by almost two orders of magnitude the record integrated luminosity reached by its predecessor KEKB. With the upgrade, the beam energy asymmetry will be reduced resulting in a lower boost. Thus, the increase in luminosity and the reduction of the boost set stringent requirements on the performance of the Belle II detector, currently under construction, in order to cope with the expected large physics rates. Consisting of two layers mounted at 14 mm and 22 mm radius from the interaction point, the new Belle II pixel vertex detector based on DEPFET technology will provide the necessary three dimensional high precision position measurements of the trajectories of charged particles. This will allow the precise reconstruction of short lived particle vertices. The physics performance of the Belle II pixel vertex detector and its impact in the reduction of experimental uncertainties will be discussed focusing on the measurement of the CP-violating parameters in B-meson decay.