The Peak Structure in the In-Flight ${}^{3}\text{He} ( K^{-} , \, Λp ) n$ Reaction Around the $\bar{K} N N$ Threshold

Abstract

We theoretically investigate the origin of the peak structure around the $K^{-} p p$ threshold observed in the in-flight ${}^{3}\text{He} ( K^{-} , \, Λp ) n$ reaction in the recent E15 experiment at J-PARC. For this purpose, we consider two scenarios to produce the peak. One is that the $Λ(1405)$ is generated but it does not correlate with $p$, and the uncorrelated $Λ(1405) p$ system subsequently decays into $Λp$. The other one is that the $\bar{K} N N$ bound state is indeed generated and decays into $Λp$. As a result, the experimental signal is qualitatively well reproduced in the $\bar{K} N N$ bound scenario, definitely discarding the uncorrelated $Λ(1405) p$ one.

5 pages, 9 EPS figures, talk given at the 14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), Kyoto, Japan, 25-30 July. 2016