What makes the peak structure of the $Λp$ invariant-mass spectrum in the $K^{-} {}^{3} {\rm He} \to Λp n$ reaction?

Abstract

Recently a peak structure was observed near the $K^{-} p p$ threshold in the in-flight ${}^{3} {\rm He} (K^{-} , \, Λp) n$ reaction of the E15 experiment at J-PARC, which could be a signal of a $\bar{K} N N$ bound state. In order to investigate what is the origin of this peak, we calculate the cross section of this reaction, in particular based on the scenario that the $\bar{K} N N$ bound state is indeed generated and decays into $Λp$. We find that the numerical result of the $Λp$ invariant-mass spectrum in the $\bar{K} N N$ bound scenario is consistent with the J-PARC E15 data.

6 pages, 6 EPS figures, talk given at the 2nd Jagiellonian Symposium on Fundamental and Applied Subatomic Physics, Krakow, Poland, 4-9 June, 2017