Analysis of Excited B Mesons with the OPAL Detector at LEP

A comprehensive high-statistics analysis of the low lying non-strange excited B meson states is performed. From 4 million hadronic <br>Z^0 decays recorded by the OPAL detector on and near to the Z^0 resonance, a sample of more than 570,000 inclusively reconstructed <br>B mesons is selected making use of improved tagging and reconstruction methods. B* mesons are reconstructed using the decay <br>B* -> B gamma. About 9,000 reconstructed B* candidates using photon conversions and more than 64,000 B* candidates using <br>photons detected in the electromagnetic calorimeter constitute the largest sample of B* mesons to date. More than 20,000 <br>orbitally-excited mesons B*_J are reconstructed using B pi combinations. A new method is used to determine the B pi <br>combinatorial background and its systematic uncertainty. The selected B* candidates are used to obtain samples enriched or depleted in <br>the decay B*_J -> B* pi (pi), where the (pi) notation refers to decay modes with or without a second accompanying pion. From the number of <br>signal candidates in the B pi mass spectra of the two samples, the first measurement of the branching ratio of orbitally-excited B mesons <br>decaying into B* pi (pi) is performed. In the framework of Heavy Quark Symmetry, a fit to the total B pi mass spectrum and a simultaneous fit to the B pi mass spectra of the <br>samples enriched or depleted in the decay B*_J -> B* pi (pi) yield the <br>mass and the width of the B_1(3/2) state, as well as the branching ratio <br>of orbitally-excited B mesons decaying into B* pi. <br>In a separate analysis, a search for the first radial excitation of B and <br>B* has been performed. An excess observed in the B pi+ pi- mass spectrum <br>is interpreted as a combined signal of B(*)' -> B(*) pi+ pi- and <br>B*_J -> B(*) pi+ pi- decays.

Author dc:creator

• Thiergen, Michael

Contributors dc:contributor

• Herten, Gregor

• B-Stern-Meson
• B-Stern-J-Meson
• HQET
• HQS

Repository record source_url

https://freidok.uni-freiburg.de/data/45

OAI identifier oai:identifier

oai:freidok.uni-freiburg.de:45