Sequential Y(nS) suppression in high-multiplicity pp collisions: the experimental case for an early, globally correlated medium
Abstract
The multiplicity-dependent suppression of (nS) states measured by CMS in pp at s=7\,TeV CMS2020, and of (2S)/J/ measured by LHCb at s=13\,TeV LHCb2024, is subjected to four multi-differential tests: cone isolation, azimuthal sectors, transverse sphericity, and prompt vs. non-prompt. Cone and sphericity close a scissors constraint: the local reading of the Comover Interaction Model is in tension with the cone data, its global reading with the sphericity data. The non-prompt flatness forces the mechanism to act at early proper times. None of the considered hadronic or string-based frameworks -- CIM local or global, PYTHIA 8 MPI Sjostrand2015, rope hadronisation Bierlich2015, CGC Ma2015, Trainor TCM Trainor2008 -- naturally satisfies the four constraints simultaneously in its published form. The surviving class is an early, globally correlated medium consistent with partonic degrees of freedom, co-occurring with the ALICE strangeness enhancement ALICESE, the long-range ridge CMSridge, and below the threshold of the partonic baryon-meson v2 ALICEv2, in a density window compatible with the Campanini \& Ferri equation of state Campanini2011.
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.