A search for doubly-charmed B decays with both charmed mesons reconstructed is performed, using about 3.8 million hadronic Z decays recorded with the ALEPH detector at LEP. A clear signal is observed in the channels B --> D(s)(D) over bar(X) and B --> D (D) over bar(X) (where D can be either a D(O), a D(+) or a D*(+)), providing the first direct evidence for doubly-charmed B decays involving no D(s) production. Evidence for associated K(S)(O) and K(+/-) production in the decays B --> D (D) over bar(X) is also presented and some candidates for completely reconstructed decays B --> D(s)(D) over bar(n pi), B --> D (D) over bar K(S)(O) and B --> D (D) over bar K(+/-) are observed. Furthermore, candidates for the two-body Cabibbo suppressed decays B(O) --> D*(-)D*(+) and B(-) --> D((*)O)D((*)-) are also observed. Measurements of the corresponding branching fractions are extracted.
|Titolo:||Observation of doubly-charmed B decays at LEP|
|Data di pubblicazione:||1998|
|Digital Object Identifier (DOI):||10.1007/s100529800924|
|Appare nelle tipologie:||1.1 Articolo in rivista|