Pole position of $\hat{I}›(1405)$ measured in $d(K^{-},n)\ddot{I}€\hat{I}\pounds$ reactions

Abstract

We measured a set of $\ddot{I}{€}^{\pm }\hat{I}{\pounds }^{\mp }$, $\ddot{I}{€}^0\hat{I}{\pounds }^0$, and $\ddot{I}{€}^{-}\hat{I}{\pounds }^0$ invariant mass spectra below and above the $\bar{K}N$ mass threshold in $K^{-}$-induced reactions on deuteron. We deduced the $S$-wave $\bar{K}N\to \ddot{I}€\hat{I}\pounds$ and $\bar{K}N\to \bar{K}N$ scattering amplitudes in the isospin 0 channel in the framework of a $\bar{K}N$ and $\ddot{I}€\hat{I}\pounds$ coupled channel. We find that a resonance pole corresponding to $\hat{I}›(1405)$ is located at 1417.7${}_{-7.4}^{+6.0}$(fitting errors)${}_{-1.0}^{+1.1}$(systematic errors) + $[-26.1_{-7.9}^{+6.0}$(fitting errors)${}_{-2.0}^{+1.7}$(systematic errors)]$i$ MeV/$c^2$, closer to the $\bar{K}N$ mass threshold than the value determined by the Particle Data Group.

8 pages, 5 figures