The study of decay with the calculation of its branching ratio

Abstract

In this paper, the decay of the meson into two vector mesons and is investigated.The first observation of the decay was reported in 2017 by LHCb collaboration, they have obtained the value of B () = (5. 01 ± 053 ± 0.27 ± 0.06)×10-4. In this study, the Feynman diagram of decay is drawn based on the standard model. In particular this diagram shows that the decay consists of tree-exchange internal w-emission graph and penguin- suppressed graph. The coefficients of a2, a3, a5 and a7 are calculated in the NLO scale. The branching ratio is calculated using the QCD factorization method, numerical values in the NLO (at mb scale) scheme is 5.33×10-4, for which are in good agreement with the experimental results. The more calculations accuracy increases, the b quark mass scales come down corresponding to that. The best answer close to the experimental value is in NLO scheme at mb scale of QCDF approach.‎

Keywords

• b meson decay
• factorization method
• feynman diagram
• form factor
• decay rate
• branching ratio