Search for charmless decays of B hadrons in hadronic and radiative modes using the DELPHI detector at LEP

Charmless hadronic decay of beauty particles can proceed through both tree level diagrams involving b → u transitions and penguin processes. Radiative (b → sγ) decays are pure penguin processes. These decays are of special interest as a test of the loop structure of the standard model and in connection with the measurement of CP violation in the B sector. A search for charmless hadronic and radiative decays of B mesons has been performed with the DELPHI detector at the LEP collider. The high tracking resolution, obtained with the silicon microvertex detector, provides efficient b-tagging and rejection of combinatorial background. In addition, the particle identification capabilities of the DELPHI ring imaging Cherenkov detector allow the separation of channels with a kaon from the pure multi-pion final states.