Correlated $\Lambda d$ pairs from the $K^{-}_{stop} A \to \Lambda d A'$ reaction

TL;DR

This study investigates correlated Lambda-deuteron pairs produced by stopped K- absorption in light nuclei, revealing a mass bump suggestive of possible kaonic nuclear clusters, using the FINUDA spectrometer.

Contribution

It reports the first observation of a Lambda-d mass bump in light nuclei, indicating potential kaonic cluster formation in nuclear absorption processes.

Findings

Observation of a Lambda-d invariant mass bump at 3251 MeV/c^2 in 6Li.

Preferential emission of Lambda and deuterons in opposite directions.

Evidence supporting the existence of kaonic nuclear clusters.

Abstract

Correlated $\Lambda d$ pairs emitted after the absorption of negative kaons at rest $K^{-}_{stop}A\to \Lambda d A'$ in light nuclei $^6Li$ and $^{12}C$ are studied. $\Lambda$-hyperons and deuterons are found to be preferentially emitted in opposite directions. The $\Lambda d$ invariant mass spectrum of $^6Li$ shows a bump whose mass is 3251$\pm$6 MeV/c$^2$. The bump mass (binding energy), width and yield are reported. The appearance of a bump is discussed in the realm of the [$\bar{K}3N$] clustering process in nuclei. The experiment was performed with the FINUDA spectrometer at DA$\Phi$NE (LNF).