Constraining the optical potential in the search for eta-mesic 4He

M. Skurzok; P. Moslal; N. G. Kelkar; S. Hirenzaki; H. Nagahiro; N. Ikeno

doi:10.1016/j.physletb.2018.04.047

paper

Constraining the optical potential in the search for eta-mesic 4He

arXiv:1802.08597 · doi:10.1016/j.physletb.2018.04.047

Abstract

A consistent description of the $dd \to$ $^{4}\hspace{-0.03cm}\mbox{He} η$ and $dd \to$ ( $^{4}$ He $η$ ) $_{b o u n d} \to X$ cross sections was recently proposed with a broad range of real ( $V_{0}$ ) and imaginary (W0), $η$ - $^{4}$ He optical potential parameters leading to a good agreement with the d d -> 4He eta data. Here we compare the predictions of the model below the $η$ production threshold, with the WASA-at-COSY excitation functions for the dd -> 3He N pi reactions to put stronger constraints on (V0, W0). The allowed parameter space (with |V_0| < \sim 60 MeV and |W_0| < \sim 7 MeV estimated at 90% CL ) excludes most optical model predictions of eta-4He nuclei except for some loosely bound narrow states.