Medium-Induced Quarkonium Dissociation at Finite Chemical Potential and Weak Magnetic Field
Indrani Nilima, Mujeeb Hasan, Mohammad Yousuf Jamal, Salman Ahamad Khan, B. K. Singh
TL;DR
The paper addresses how a hot QCD medium with finite quark chemical potential and a weak magnetic field modifies heavy quarkonium. It constructs a complex heavy-quark potential from a HTL-resummed gluon propagator augmented by a dimension-two gluon condensate to obtain a complex dielectric permittivity, enabling binding energy calculations from the real part and thermal widths from the imaginary part. Using a resonance-melting criterion, it reveals a sequential suppression pattern where binding energies decrease and widths grow with temperature, with finite density and weak magnetic fields providing subleading shifts. The results underscore temperature as the dominant factor in quarkonium dissociation in the QGP and bear on heavy-ion phenomenology, while outlining avenues for future work on stronger fields and real-time dynamics.
Abstract
We investigate the in-medium modification and dissociation of heavy quarkonium in a hot QCD medium at finite quark chemical potential and in the weak magnetic-field regime. Starting from the one-loop resummed gluon propagator in the imaginary-time formalism, and incorporating non-perturbative effects through a phenomenological correction to the HTL description, we compute the real and imaginary parts of the dielectric permittivity. This, in turn, leads to a complex heavy-quark potential: the real part is used to determine binding energies by solving the nonrelativistic Schrödinger equation, while the imaginary part generates thermal decay widths, dominated by Landau damping. Within the explored parameter range, temperature has the greatest control over Debye screening, potential modification, and quarkonium stability, whereas finite density and weak magnetic fields introduce comparatively smaller quantitative changes. As the temperature increases, binding energies decrease and thermal widths grow, giving rise to the expected hierarchy between ground and excited states and a sequential suppression pattern in the dissociation temperatures. Overall, our results indicate that while finite chemical potential and weak magnetic fields can shift quarkonium properties in a measurable way, thermal effects remain the primary driver of dissociation, with direct relevance for heavy-ion collision phenomenology.
