SPIN-QGP · Probing spin dynamics in the QGP via spin-dependent Λ–Λ observables

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Project objective

Quantum Chromodynamics (QCD) is the theory of the strong interaction, yet its non-perturbative regime, where quarks and gluons bind into hadrons, remains incompletely understood. Heavy-ion collisions at the LHC create a strongly interacting medium, the quark–gluon plasma (QGP). The role of spin in this quantum fluid, and its relation to quantum correlations and spin-dependent forces, is still largely unexplored beyond single-particle polarization measurements. This project pioneers spin-dependent studies using Λ hyperons, whose parity-violating weak decay self-analyzes spin by its decay particle momentum. Two objectives are proposed: (1) measure Λ–Λ two-particle spin correlations to access singlet and triplet components via the relative angle of decay protons 〈cosΔθ〉) in the rest frame of Λs and to study spin dynamics of QGP (2) develop spin-dependent femtoscopy to separate spin channels in the Λ–Λ correlation function and extract spin-dependent scattering parameters and interaction potential. These observables probe whether hadronization preserves quark-spin correlations, whether initial-state spin fluctuations survive the QGP, and the spin structure of hyperon–hyperon forces, providing complementary constraints to lattice QCD and hypernuclear data. The analysis exploits ALICE Run-3 Pb–Pb data (over 20 billion events), improved vertex precision with detector upgrades, and ML-based selection to secure statistical power and control systematics (feed-down, acceptance, backgrounds). By establishing spin correlations as new QCD observables, the project integrates quantum information ideas into heavy-ion physics, delivers unprecedented constraints on baryon interactions, and trains a researcher at the interface of experiment, theory, and data science.

Original text from CORDIS.

Participants

• POLITECHNIKA WARSZAWSKA · WarszawaCoordinatorPoland
• ORGANISATION EUROPEENNE POUR LA RECHERCHE NUCLEAIRE · GENEVE 23Switzerland

Links

• View on CORDIS
• DOI: 10.3030/101284600