Evidence of the low-lying baryon $\hat{I}{\pounds }^{\ast }(1/2^{-})$ in the process $\hat{I}{›}_c^{+}\to \hat{I}\cdot \ddot{I}{€}^{+}\hat{I}›$

Abstract

Motivated by the Belle measurements of the process $\hat{I}{›}_c^{+}\to \hat{I}\cdot \ddot{I}{€}^{+}\hat{I}›$, we investigate this process by considering the contributions from the $\hat{I}›(1670)$, $a_0(980)$, and $\hat{I}\pounds (1385)$. In addition, we also consider the predicted low-lying baryon $\hat{I}{\pounds }^{\ast }(1/2^{-})$. Our results involving the $\hat{I}{\pounds }^{\ast }(1/2^{-})$ are favored by fitting to the Belle data of the $\hat{I}\cdot \hat{I}›$ and $\ddot{I}{€}^{+}\hat{I}›$ invariant mass distributions. Furthermore, we predict the $\hat{I}\cdot \ddot{I}{€}^{+}$ invariant mass distribution and the angular distribution $d\hat{I}“/d\cos \hat{I}¸$, which are significantly different depending on whether or not the contribution from the $\hat{I}{\pounds }^{\ast }(1/2^{-})$ is considered. Finally, we show that, with the contribution from the $\hat{I}{\pounds }^{\ast }(1/2^{-})$, the calculated Dalizt plot agrees with the Belle measurements. Future precise measurements of the process $\hat{I}{›}_c^{+}\to \hat{I}\cdot \ddot{I}{€}^{+}\hat{I}›$ could shed further light on the existence of the low-lying $\hat{I}{\pounds }^{\ast }(1/2^{-})$.

11 pages, 14 figures, comments are welcome