Year: 2026
Type: preprint
Abstract: The lifetime of the strong magnetic field generated in relativistic heavy-ion collisions remains one of the major open questions in the study of the quark--gluon plasma. We propose heavy-quark spin precession as a probe to quantify the magnetic field and its profile in such collisions. We investigate the Larmor evolution of polarized charm and bottom quarks propagating through an expanding quark--gluon plasma in the presence of the magnetic field. We show that realistic magnetic-field strengths and lifetimes generate measurable accumulated precession phases prior to hadronization, leading to characteristic charge-dependent polarization splittings between $Λ_c^+$ and $\barΛ_c^-$, as well as between $Λ_b^0$ and $\barΛ_b^0$, through the mixing of transverse and longitudinal polarization components. The predicted signals exhibit distinctive transverse-momentum and quark-mass dependence, providing complementary sensitivity to the magnetic-field lifetime in the charm and bottom sectors. Our results suggest heavy-flavor polarization, especially in the charm sector, as a quantitative probe for the space--time evolution of magnetic fields in relativistic heavy-ion collisions.
Source: arXiv (Cornell University)
Authors: Sahu, Dushmanta, Singh, Captain R.
Institution: Universidad Nacional Autónoma de México
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214010348