2001/12/31 by Susan Gardner, S. Gardner, Ulf-G. Meißner · 3 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.65.094004
published as Phys.Rev.D65:094004,2002 · 26 pages, 8 figs, published version. typos fixed, minor changes
arxiv created 2002/02/17 · openalex publication_date 2002/04/15 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We examine the role of B0(B0)\ensuremath→\ensuremathσ\ensuremathπ0\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathπ0 decay in the Dalitz plot analysis of B0(B0)\ensuremath→\ensuremathρ\stackrel\ensuremath→\ensuremathπ\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathπ0 decays, employed to extract the CKM parameter \ensuremathα. The \ensuremathσ\ensuremathπ channel is significant because it can break the relationship between the penguin contributions in \stackrel\ensuremath→B\ensuremathρ0\ensuremathπ0, \stackrel\ensuremath→B\ensuremathρ+\ensuremathπ^\ensuremath-, and \stackrel\ensuremath→B\ensuremathρ^\ensuremath-\ensuremathπ+ decays consequent to an assumption of isospin symmetry. Its presence thus mimics the effect of isospin violation. The \ensuremathσ\ensuremathπ0 state is of definite CP, however; we demonstrate that the \stackrel\ensuremath→B\ensuremathρ\ensuremathπ analysis can be generalized to include this channel without difficulty. The \ensuremathσ or f0(400\ensuremath-1200) ``meson'' is a broad I=J=0 enhancement driven by strong \ensuremathπ\ensuremathπ rescattering; a suitable scalar form factor is constrained by the chiral dynamics of low-energy hadron-hadron interactions---it is rather different from the relativistic Breit-Wigner form adopted in earlier \stackrel\ensuremath→B\ensuremathσ\ensuremathπ and \stackrel\ensuremath→D\ensuremathσ\ensuremathπ analyses. We show that the use of this scalar form factor leads to an improved theoretical understanding of the measured ratio Br(B0\ensuremath→\ensuremathρ^\ensuremath∓\ensuremathπ^\ifmmode±\else\textpm\fi)/Br(B^\ensuremath-\ensuremath→\ensuremathρ0\ensuremathπ^\ensuremath-).