2010/12/20 by J. O. Eeg, Jan O. Eeg, Teresa L. Palmer +1
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.83.054016
published as Phys.Rev.D83:054016,2011 · The submitted Latex version correspond to 23 pages in ps-version and contains 4 figures
arxiv created 2010/12/20 · openalex publication_date 2011/03/10 · arxiv updated 2011/03/22 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The decay modes of the type B\ensuremath→\ensuremathπ\ensuremathπ are dynamically different. For the case Bd0\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath- there is a substantial factorized contribution which dominates. In contrast, the decay mode Bd0\ensuremath→\ensuremathπ0\ensuremathπ0 has a small factorized contribution, being proportional to a small Wilson coefficient combination. However, for the decay mode Bd0\ensuremath→\ensuremathπ0\ensuremathπ0 there is a sizeable nonfactorizable (color suppressed) contribution due to soft (long distance) interactions, which dominate the amplitude. We estimate the branching ratio for the mode Bd0\ensuremath→\ensuremathπ0\ensuremathπ0 in the heavy quark limit for the b quark. In order to estimate color suppressed contributions we treat the energetic light (u, d, s) quark within a variant of Large Energy Effective Theory combined with a recent extension of chiral quark models in terms of model- dependent gluon condensates. We find that our calculated color suppressed amplitude is suppressed by a factor of order \ensuremathΛQCD/mb with respect to the factorizable amplitude, as it should according to QCD-factorization. Further, for reasonable values of the constituent quark mass and the gluon condensate, the calculated nonfactorizable amplitude for Bd0\ensuremath→\ensuremathπ0\ensuremathπ0 can easily accommodate the experimental value. Unfortunately, the color suppressed amplitude is very sensitive to the values of these model-dependent parameters. Therefore fine-tuning is necessary in order to obtain an amplitude compatible with the experimental result for Bd0\ensuremath→\ensuremathπ0\ensuremathπ0. A possible link to the triangle anomaly is discussed.