Indications of conical emission of charged hadrons at the BNL relativistic heavy ion collider

Phys Rev Lett. 2009 Feb 6;102(5):052302. doi: 10.1103/PhysRevLett.102.052302. Epub 2009 Feb 3.

Abstract

Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d+Au, and Au+Au collisions at sqrt[s_{NN}]=200 GeV by the STAR experiment. Dijet structures are observed in pp, d+Au and peripheral Au+Au collisions. An additional structure is observed in central Au+Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be theta=1.37+/-0.02(stat)-0.07+0.06(syst), independent of p_{ perpendicular}.