Shedding Light on Hexaquarks

Abstract

Several new findings in the four, five and six quark systems reheat the interest in the field of multiquark states (beyond the trivial [Formula: see text] and [Formula: see text]). A lot of progress has recently been made in the 6q sector, on both the theoretical and experimental side. A resonance like structure observed in double-pionic fusion to the deuteron, at M = 2.38 GeV with [Formula: see text] = 70 MeV and [Formula: see text] has been consistently observed in a wealth of reaction channels, supporting the existence of a resonant dibaryon state - the [Formula: see text]. These studies include measurement of all the principle strong decay channels in pn collisions in the quasifree mode by the WASA-at-COSY and HADES collaborations. The internal structure of the [Formula: see text] is largely unknown. It can contain various ”hidden color” 6q configurations, [Formula: see text] molecular states with angular momentum L = 0,2,4,6 as well as meson-assisted dressed dibaryon structures. The large set of experimental data obtained to date gives some constraints on the internal structure of the [Formula: see text] dibaryon, but does not settle the issue. The [Formula: see text] is the only multiquark state which can be produced copiously at current facilities, offering unique access to information beyond its basic quantum numbers, particularly its physical size and internal structure.