Starting from a sample of four million hadronic Z decays collected with the ALEPH detector at LEP, 404 charged and neutral B mesons are fully reconstructed and used to look for resonant structure in the B pi. system. An excess of events is observed above the expected background in the B pi mass spectrum at a mass approximate to 5.7 GeV/c(2), consistent with the production and decay to B(*)pi of the B** states predicted by Heavy Quark Symmetry (HQS). In the framework of HQS, it is found that the mass of the B-2* State is (5739(-11)(+8)(stat)(-4)(+6)(syst))MeV/c(2) and the relative production rate of the B ** system is BR(b --> B** --> B(*)pi)/BR(b --> Bu,d)= (31 +/- 9(stat)(-5)(+6)(syst))%. In the same sample of B mesons, significant B pi(+/-) charge-flavour correlations are observed, which may prove important for tagging the initial B state in future CP violation studies.
Resonant structure and flavour tagging in the B pi(+/-) system using fully reconstructed B decays
BATIGNANI, GIOVANNI;BETTARINI, STEFANO;CIOCCI, MARIA AGNESE;FERRANTE, ISIDORO;FORTI, FRANCESCO;GIORGI, MARCELLO;MESSINEO, ALBERTO MARIA;RIZZO, GIULIANA;TONELLI, GUIDO EMILIO;
1998-01-01
Abstract
Starting from a sample of four million hadronic Z decays collected with the ALEPH detector at LEP, 404 charged and neutral B mesons are fully reconstructed and used to look for resonant structure in the B pi. system. An excess of events is observed above the expected background in the B pi mass spectrum at a mass approximate to 5.7 GeV/c(2), consistent with the production and decay to B(*)pi of the B** states predicted by Heavy Quark Symmetry (HQS). In the framework of HQS, it is found that the mass of the B-2* State is (5739(-11)(+8)(stat)(-4)(+6)(syst))MeV/c(2) and the relative production rate of the B ** system is BR(b --> B** --> B(*)pi)/BR(b --> Bu,d)= (31 +/- 9(stat)(-5)(+6)(syst))%. In the same sample of B mesons, significant B pi(+/-) charge-flavour correlations are observed, which may prove important for tagging the initial B state in future CP violation studies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.