Thanks to Axil Axil for the following comment:
As per can, a new, recently published paper from Leif Holmlid. This one is open access.
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Laser-Induced Nuclear Processes in Ultra-Dense Hydrogen Take Place in Small Non-superfluid HN(0) Clusters
Abstract: Charged and neutral kaons are formed by impact of pulsed lasers on ultra-dense hydrogen H(0). This superfluid material H(0) consists of clusters of various forms, mainly of the chain-cluster type H2N. Such clusters are not stable above the transition temperature from superfluid to normal matter. In the case studied here, this transition is at 525 K for D(0) on an Ir target, as reported previously. Mesons are formed both below and above this temperature. Thus, the meson formation is not related to the long chain-clusters H2N but to the small non-superfluid cluster types H3(0) and H4(0) which still exist on the target above the transition temperature. The nuclear processes forming the kaons take place in such clusters when they are transferred to the lowest s = 1 state with H–H distance of 0.56 pm. At this short distance, nuclear processes are expected within 1 ns. The superfluid chain-cluster phase probably has no direct importance for the nuclear processes. The clusters where the nuclear processes in H(0) take place are thus quite accurately identified.
H3(0) is a flat triangular 3 atom molecule