Search for strange tribaryon states in the inclusive ^4He(K^{-}_{stopped}, p) reaction

TL;DR

This study searched for strange tribaryon states in helium-4 using stopped kaon reactions but found no significant signals, setting upper limits on their formation probabilities.

Contribution

First experimental search for strange tribaryon states in helium-4 using the ($K^-_{stopped}, p$) reaction with no observed signals, establishing upper limits on their production rates.

Findings

No significant narrow structures observed in the mass range 3000-3200 MeV/c^2.

Upper limits on formation branching ratios were set at 95% confidence level.

Constraints placed on the existence of narrow tribaryon states with widths up to 40 MeV/c^2.

Abstract

A search for tribaryon states was performed at KEK-PS. We adopted the $^4$He($K^-_{stopped}, p)$ reaction to populate the states with strangeness -1, charge 0 and isospin 1. No significant narrow structure was observed in the mass region from 3000 to 3200 MeV/c^2 in an inclusive missing mass spectrum. The upper limit of the formation branching ratio was determined to be ($1\sim3)\times 10^{-4}$, ($0.7\sim2)\times 10^{-3}$ and ($2\sim8) \times 10^{-3}$/($stopped K^{-}$) with 95 % confidence level for narrow states with an assumed width of 0, 20 and 40 MeV/c^2, respectively.