Momentum broadening in weakly coupled quark-gluon plasma (with a view to finding the quasiparticles within liquid quark-gluon plasma)
Author(s)D'Eramo, Francesco; Lekaveckas, Mindaugas; Liu, Hong; Rajagopal, Krishna
MetadataShow full item record
We calculate P (k [subscript ⊥]), the probability distribution for an energetic parton that propagates for a distance L through a medium without radiating to pick up transverse momentum k [subscript ⊥], for a medium consisting of weakly coupled quark-gluon plasma. We use full or HTL self-energies in appropriate regimes, resumming each in order to find the leading large-L behavior. The jet quenching parameter [ˆ over q] is the second moment of P (k [subscript ⊥]), and we compare our results to other determinations of this quantity in the literature, although we emphasize the importance of looking at P (k [subscript ⊥]) in its entirety. We compare our results for P (k [subscript ⊥]) in weakly coupled quark-gluon plasma to expectations from holographic calculations that assume a plasma that is strongly coupled at all length scales. We find that the shape of P (k [subscript ⊥]) at modest k [subscript ⊥] may not be very different in weakly coupled and strongly coupled plasmas, but we find that P (k [subscript ⊥]) must be parametrically larger in a weakly coupled plasma than in a strongly coupled plasma — at large enough k [subscript ⊥]. This means that by looking for rare (but not exponentially rare) large-angle deflections of the jet resulting from a parton produced initially back-to-back with a hard photon, experimentalists can find the weakly coupled short-distance quark and gluon quasiparticles within the strongly coupled liquid quark-gluon plasma produced in heavy ion collisions, much as Rutherford found nuclei within atoms or Friedman, Kendall and Taylor found quarks within nucleons.
DepartmentMassachusetts Institute of Technology. Center for Theoretical Physics; Massachusetts Institute of Technology. Department of Physics
Journal of High Energy Physics
D’Eramo, Francesco, Mindaugas Lekaveckas, Hong Liu, and Krishna Rajagopal. “Momentum Broadening in Weakly Coupled Quark-Gluon Plasma (with a View to Finding the Quasiparticles Within Liquid Quark-Gluon Plasma).” J. High Energ. Phys. 2013, no. 5 (May 2013).
Final published version