Study of $\psi (2S)$ decays into $\gamma K^{+}{K}^{-}$ and $\gamma {\pi }^{+}{\pi }^{-}$

Abstract

Radiative charmonium decays from the BESII sample of 14$\times 10^6$ $\psi (2S)$-events into two different final states, $\gamma K^{+}{K}^{-}$ and $\gamma {\pi }^{+}{\pi }^{-}$, are analyzed. Product branching fractions for $\psi (2S)\to \gamma X\to \gamma {\pi }^{+}{\pi }^{-}$, $\gamma K^{+}{K}^{-}$ are given, where $X=f_2(1270)$, $f_0(1500)$, and $f_0(1710)$ in ${\pi }^{+}{\pi }^{-}$ and $f_2(1270)$, $f_2^{\prime }(1525)$, and $f_0(1700)$ in $K^{+}{K}^{-}$. An angular analysis gives the ratios of the helicity projections for the $f_2(1270)$ in $\psi (2S)\to \gamma f_2(1270)\to \gamma {\pi }^{+}{\pi }^{-}$.

arXiv comment9 pages, 5 figures