Study of the Decay B0(B¯0)→ρ+ρ− , and Constraints on the Cabibbo-Kobayashi-Maskawa Angle α

Le résumé fourni par la source

Using a data sample of $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric $B$ Factory at SLAC, we measure the ${B}^{0}({\overline{B}}^{0})\ensuremath{\rightarrow}{\ensuremath{\rho}}^{+}{\ensuremath{\rho}}^{\ensuremath{-}}$ branching fraction as $[30\ifmmode\pm\else\textpm\fi{}4(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}5(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and a longitudinal polarization fraction of ${f}_{L}=0.99\ifmmode\pm\else\textpm\fi{}0.03(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{\ensuremath{-}0.03}^{+0.04}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})$. We measure the time-dependent-asymmetry parameters of the longitudinally polarized component of this decay as ${C}_{L}=\ensuremath{-}0.17\ifmmode\pm\else\textpm\fi{}0.27(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.14(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})$ and ${S}_{L}=\ensuremath{-}0.42\ifmmode\pm\else\textpm\fi{}0.42(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.14(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})$. We exclude values of $\ensuremath{\alpha}$ between 19\ifmmode^\circ\else\textdegree\fi{} and 71\ifmmode^\circ\else\textdegree\fi{} (90% C.L.).

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