Alladi Ramakrishnan Hall

Bound to ubound stata transition of heavy quarkonia in the cooling phase of QGP

Nirupam Dutta

NISER

This is now beyond doubt that heavy quarkonium states should be described through
their real time dynamics in QGP in order to employ them as a convincing probe for
the medium. One important reason behind this is that a quark antiquark bound state
can only be described through a time dependent potential in the evolving quark
gluon plasma (QGP). Recent studies also have shown that the effective heavy quark
potential is actually a complex quantity which essentially suggests a decay of the
bund states no matter the medium is evolving or not. Now added to that when the
medium temperature falls off rapidly, the bound states evolve non adiabatically.
As a result, quarkonia can make transitions to various bound and scattering states
where the later leads to dissociation of bound states even though the Debye
screening mechanism may allow them to survive. This fact is counter intuitive and
contrary to the usual perception of quarkonia suppression through color screening
or gluon dissociation mechanism. We show some quantitative prediction of such
transitions to unbound or scattering states of relevant charmonium and bottomonium
states during the cooling phase of QGP by using time dependent perturbation
theory.