Charming charm, beautiful bottom and quark-gluon plasma in the Large Hadron Collider era

After a few microseconds of the creation of our Universe through the Big Bang, the primordial matter was believed to be a soup of the fundamental constituents of matter - quarks and gluons. This is expected to be created in the laboratory by colliding heavy nuclei at ultra-relativistic speeds. A plasma of quarks and gluons, called quark-gluon plasma (QGP) can be created at the energy and luminosity frontiers in the Relativistic Heavy Ion Collider, at Brookhaven National Laboratory, New York, USA, and the Large Hadron Collider at CERN, Geneva, Switzerland. Heavy quarks, namely the charm and bottom quarks, are considered as novel probes to characterize QGP, and hence the produced quantum chromodynamics matter. Heavy quark transport coefficients play a significant role in understanding the properties of QGP. Experimental measurements of nuclear suppression factor and elliptic flow can constrain the heavy quark transport coefficients, which are key ingredients for phenomenological studies, and they help to disentangle different energy loss mechanisms. We give a general perspective of the heavy quark drag and diffusion coefficients in QGP and discuss their potentials as probes to disentangle different hadronization mechanisms, as well as to probe the initial electromagnetic fields produced in non-central heavy-ion collisions. Experimental perspectives on future measurements are discussed with special emphasis on heavy flavours as the next-generation probes in view of new technological developments.

Automated summary

Researchers reproduced the primordial soup of quarks and gluons after the Big Bang through experiments colliding heavy nuclei, aiming to understand the nature of quark-gluon plasma. The heavy quark transport coefficients and experimental measurements are crucial in studying the properties of QGP and different energy loss mechanisms. Heavy quarks serve as probes to disentangle various hadronization mechanisms and investigate the initial electromagnetic fields in non-central heavy-ion collisions.