The decay rate of $\psi (2S)$ to ${\Lambda }_c+\overline{{\Sigma }^{+}}$ in SM and beyond

Abstract

With rapid growth of the database of the BES III and the proposed super flavor factory, measurement on the rare $\psi (2S)$ decays may be feasible, especially the weak decays into baryon final states. In this work we study the decay rate of $\psi (2S)$ to ${\Lambda }_c+\overline{{\Sigma }^{+}}$ in the SM and physics beyond the SM (here we use the unparticle model as an example). The QPC model is employed to describe the creation of a pair of $q\bar{q}$ from vacuum. We find that the rate of $\psi (2S)\to {\Lambda }_c+\overline{{\Sigma }^{+}}$ is at order of $10^{-10}$ in the SM, whereas the contribution of the unparticle is too small to be substantial. Therefore if a large branching ratio is observed, it must be due to new physics beyond SM, but by no means the unparticle.

Comments: 9 pages, 1 figures