Minimal-length corrections to hyperon polarization in rotating quark gluon plasma

Abstract

Hyperon polarization in relativistic heavy-ion collisions provides a sensitive probe of thermal vorticity and of the operator structure of local equilibrium. We investigate an isotropic generalized uncertainty principle (GUP) introduced through a spin-independent scalar deformation of the one-particle phase-space density of states in the local rest frame (LRF). The analysis is formulated with the Belinfante-Rosenfeld local-equilibrium operator, the standard on-shell dispersion relation, and the Pauli-Lubanski/axial-Wigner representation of the spin-$1/2$ observable, retaining terms linear in the GUP coefficient and in hydrodynamic gradients. Within this framework, the same scalar GUP factor appears in the scalar and axial phase-space contributions and cancels from the local mean-spin ratio at fixed spacetime point and momentum. Consequently, the leading GUP contribution to an experimentally relevant polarization observable arises through the Cooper-Frye freeze-out integrals and can be written in terms of a covariance between the LRF momentum invariant and the local spin kernel. This cancellation is a consequence of the scalar density-of-states modification within a fixed pseudogauge and does not imply pseudogauge independence of the polarization observable. For $\Lambda$ hyperons, a Maxwell-Boltzmann thermal estimate shows that the dependence on freeze-out temperature and fluid-dynamical correlations is substantially larger than the Fermi-Dirac correction, which remains negligible over the temperature range considered. Present LHC precision corresponds only to a formal linear sensitivity of order $10$-$30~\mathrm{GeV}^{-2}$. Since this interval lies beyond the domain in which the linear GUP expansion is reliable, no exclusion limit is inferred. Differential measurements of hyperon polarization as functions of momentum, rapidity, collision centrality, and azimuthal harmonic structure provide the most direct experimental avenue for testing the predicted covariance dependence.