Measurement of Lambda hyperons spin correlation in pp and pPb collisions at CMS

7 May 2026, 11:35
20m
Sala IMPERIALE B. (Hotel Carlton)

Sala IMPERIALE B.

Hotel Carlton

Talk WG5 Spin and 3D Structure WG5 Spin and 3D-structure

Speaker

Jieke Wang

Description

The spin correlations of $\Lambda$ hyperons offer a direct window into QCD spin dynamic, including spin-orbit coupling, polarization transfer during hadronization, and possible local spin entanglement in the fragmentation process. With the high-statistics data collected by the CMS experiment, we present the first spin correlation results for $\Lambda\Lambda$, $\Lambda\bar{\Lambda}$ and $\bar{\Lambda}\bar{\Lambda}$ in pp collisions $\sqrt{s}= 13$ TeV and pPb collisions at $\sqrt{s_{NN}}= 8.16$ TeV as functions of spatial distance ($\Delta R = \sqrt{\Delta \eta^{2} + \Delta \phi^{2}}$) between the hyperon pairs. These high‑precision measurements provide new constraints on microscopic models of spin generation and hadronization, enabling discrimination between fragmentation and recombination mechanisms and opening a novel experimental avenue for QCD spin studies.

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