2005/02/28 by Belle Collaboration, K. Abe, I. Adachi +95
Physics and Astronomy · #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex
paper · pdf · doi:10.1103/physrevlett.95.101801
published as Phys.Rev.Lett.95:101801,2005 · 10 pages, 4 figures, the title and abstract have been changed on May 13th, submitted to Phys. Rev. Lett., replaced on Apr. 30th to a paper draft that is submitted to PRL. Original comments: 13 pages, 6 figures, contributed to the 2005 Aspen Winter Conference on The Higest Energy Physics, Feb. 13-19, 2005, Aspen, Colorado, U.S.A
arxiv created 2005/05/14 · openalex publication_date 2005/08/31 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We present a new measurement of the time-dependent CP-violating parameters in B0\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath- decays with 275\ifmmode×\else\texttimes\fi106 BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+e^\ensuremath- collider operating at the \ensuremathΥ(4S) resonance. We find 666\ifmmode±\else\textpm\fi43 B0\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath- events and measure the CP-violating parameters: S_\ensuremathπ\ensuremathπ=\ensuremath-0.67\ifmmode±\else\textpm\fi0.16(stat)\ifmmode±\else\textpm\fi0.06(syst) and A_\ensuremathπ\ensuremathπ=+0.56\ifmmode±\else\textpm\fi0.12(stat)\ifmmode±\else\textpm\fi0.06(syst). We find evidence for large direct CP violation with a significance greater than 4 standard deviations for any S_\ensuremathπ\ensuremathπ value. Using isospin relations, we obtain 95.4% confidence intervals for the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle \ensuremathφ2 of 0\ifmmode^∘\else\textdegree\fi<\ensuremathφ2<19\ifmmode^∘\else\textdegree\fi and 71\ifmmode^∘\else\textdegree\fi<\ensuremathφ2<180\ifmmode^∘\else\textdegree\fi.