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

TL;DR

This paper estimates the decay rate of $ ext{psi}(2S)$ to $ ext{Lambda}_c$ and $ar{ ext{Sigma}}^+$ within the Standard Model and beyond, finding the SM predicts an extremely small rate and unparticle physics unlikely to cause observable effects.

Contribution

It provides a theoretical estimate of the decay rate in the SM and evaluates the potential impact of unparticle physics beyond the SM on this decay channel.

Findings

SM predicts a decay rate of about 10^{-10}

Unparticle contribution is negligible

Large observed rates would indicate new physics beyond SM

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 $\psi(2S)\rightarrow \Lambda_c+\overline{\Sigma^+}$ 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.