Angular dependence of jet quenching indicates its strong enhancement near the QCD phase transition

We study dependence of jet quenching on matter density, using “tomography†of the fireball provided by RHIC data on azimuthal anisotropy v2 of high pt hadron yield at different centralities. Slicing the fireball into shells with constant (entropy) density, we derive a “layer-wise geometrical limit†v2maxâ ¡ which is indeed above the data v2<v2maxâ¡. Interestingly, the limit is reached only if quenching is dominated by shells with the entropy density exactly in the near-Tc region. We show two models that simultaneously describe the high pt v2 and RA-A data and conclude that such a description can be achieved only if the jet quenching is few times stronger in the near-Tc region relative to QGP at T>Tc. One possible reason for such enhancement may be recent indications that the near-Tc region is a magnetic plasma of relatively light color-magnetic monopoles.