Production of excited beauty states in Z decays

ALEPH Collaboration (1995) Production of excited beauty states in Z decays. Zeitschrift für Physik C Particles and Fields, 69 (1). pp. 393-404. ISSN 0170-9739

Abstract

A data sample of about 3.0 million hadronicZ decays collected by the ALEPH experiment at LEP in the years 1991 through 1994 is used to make an inclusive selection of B hadron events. In this event sample 4227±140±252B* mesons in the decayB*→Bγ and 1944±108±161B**u,d mesons decaying into a B meson and a charged pion are reconstructed. Here and in the followingB**u,d denotes the eightL=1(bū) and (bd) states and their charge conjugate. For the well establishedB* meson the following quantities are obtained:ΔM=MB*−MB=(45.30±0.35±0.87) MeV/c2 andNB*/(NB+NB*)=(77.1±2.6±7.0)%. The angular distribution of the photons in theB* rest frame is used to measure the relative contribution of longitudinalB* polarization states to beσL/(σL+σT)=(33±6±5)%. In theM(Bπ)−M(B) mass difference resonance structure is observed at (424±4±10) MeV/c2, for which the shape and position is consistent with the expectation forB**u,d states decaying intoB(*)π±. The relative production rate is determined to beBR(Z→b→B ∗∗ u,d ) BR(Z→b→B u,d ) =[27.9±1.6(stat)±5.9(syst) +3.9 −5.6 (model)]% where the third error reflects the uncertainty due to different production and decay models for the broadB**u,d states.