par Abreu, Pedro;Lemonne, Jacques 
;Tomaradze, A.;Vander Velde, Catherine ;Van Doninck, Walter;Verbeure, F;Wickens, John H. ; [et al.]
Référence Zeitschrift für Physik. C, Particles and fields, 68, 3, page (353-362)
Publication Publié, 1995-09
;Tomaradze, A.;Vander Velde, Catherine ;Van Doninck, Walter;Verbeure, F;Wickens, John H. ; [et al.]Référence Zeitschrift für Physik. C, Particles and fields, 68, 3, page (353-362)
Publication Publié, 1995-09
Article révisé par les pairs
| Résumé : | The decay B*→Bγ has been observed with the DELPHI detector at LEP, where the B* meson is produced in Z boson decays. The combination of inclusively reconstructed B mesons with well-measured converted photons yields a measurement of the flavour-averaged B*-B mass difference of 45.5±0.3 (stat.) ±0.8 (syst.) MeV/c2. 95% confidence level upper limits at 6 MeV/c2 are placed on both the isospin (i.e. B+-B0) and the Bs-Bud splitting of the mass difference. The production ratio of B* to B mesons in Z decays is measured to be 0.72±0.03 (stat.) ±0.06 (syst.). Limits on the production cross-section of other hypothetical excited B hadron states decaying radiatively are established. The differential B* cross section has been measured to be in good agreement with the average b fragmentation, yielding an average fractional B* energy of 〈xE〉=0.695±0.009 (stat.) ±0.013 (syst.). From the decay angular distribution the relative contribution of longitudinal B* polarisation states is measured to be σL/(σL + σT) = 0.32 ± 0.04 (stat.) ±0.03 (syst.). © 1995 Springer-Verlag. |
