Comments on the CMS discovery of the "Ridge" in High Multiplicity pp collisions at LHC

Understand

A very recent paper by the CMS collaboration \cite{cms_ridge} has created large discussion in the media, which call it important but did not explain why, in some places even calling it "unundestandable".

• While it is of course too soon to know what causes the correlations in question, a very similar observation in heavy ion collisions at RHIC has rather simple explanation related to explosion of high energy density matter.
• Perhaps this observation is the first hint for an explosive behavior in pp, which was anticipated and looked for for decades, yet never been seen.