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Résumé |
Different degrees of freedom dominate QCD across its phase diagram, notably
hadrons at low temperatures (and chemical potentials) and quarks and gluons at
high temperatures. However, studying the relevant content of a QCD medium across
the phase diagram is challenging. Recently, we proposed an observable that appears
sensitive to the quark content of the active degrees of freedom, the net quark
number gain. It correlates the Polyakov loop, the typical confinement order
parameter, with the medium’s net quark number, providing information on the
thermal bath's reaction to a static quark probe. While a static quark does not
significantly affect the medium at high temperatures, the net quark number gain
shows the bath's tendency to form hadron-like configurations at low temperatures,
which would screen the probe’s color charge. Interestingly, it allows one to
distinguish meson-like and baryon-like configurations. The net quark number gain
also helps explain how a single quark/antiquark can be added to a supposedly
confining medium in the first place: the latter provides the missing
quarks/antiquarks to form hadronic states.
In this talk, I will sketch the derivation of this result for temperatures much
smaller than the quark masses [1]. Moving towards realistic (small) quark masses,
I discuss results from a PNJL model [2] and give an overview of ongoing work. |
