Speaker
Description
Ridge-like correlations and strangeness enhancement observed in high-multiplicity hadronic collisions motivate searches in the much smaller and cleaner environment of $e^{+}e^{-}$ annihilation. In this talk, we summarize two-particle correlation results from Belle and ALEPH, including a recent ALEPH study using a $W^{+}W^{-}$-enhanced selection that accesses higher-multiplicity multijet final states. Moreover, multiparticle-cumulant measurements will test whether possible anisotropies arise from genuine many-particle correlations and whether this approach can suppress nonflow effects in small collision systems. As a complementary study, a DELPHI open-data measurement of the charged-kaon-to-charged-pion ratio as a function of event activity at the $Z$ pole shows no significant multiplicity-dependent enhancement within the current precision. These studies constrain whether collectivity and modified hadrochemistry can emerge from parton showering and hadronization alone in the smallest collision systems. The implications of these results are discussed.
| Secondary track | 1. Hot and Dense QCD Matter |
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