Study of B Decays to Charmonium States: B→ηcK and B→χc0K

Le résumé fourni par la source

In a sample of $9.66\ifmmode\times\else\texttimes\fi{}{10}^{6}B\overline{B}$ pairs collected with the CLEO detector we make the first observation of $B$ decays to an ${\ensuremath{\eta}}_{c}$ and a kaon. We measure branching fractions $B({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}{K}^{+})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({0.69}_{\ensuremath{-}0.21}^{+0.26}\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}0.20)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $B(B\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}K\ifmmode^\circ\else\textdegree\fi{})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({1.09}_{\ensuremath{-}0.42}^{+0.55}\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.31)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, where the first error is statistical, the second is systematic, and the third is from the ${\ensuremath{\eta}}_{c}$ branching fraction uncertainty. From these we extract the ${\ensuremath{\eta}}_{c}$ decay constant in the factorization approximation, ${f}_{{\ensuremath{\eta}}_{c}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}335\ifmmode\pm\else\textpm\fi{}75\mathrm{MeV}$. We also search for $B$ decays to a ${\ensuremath{\chi}}_{c0}$ and a kaon. No evidence for a signal is found and we set $90%$ C.L. upper limits: $B({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c0}{K}^{+})<4.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $B(B\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c0}K\ifmmode^\circ\else\textdegree\fi{})<5.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.