Jet quenching measurements at RHIC

Abstract

Experimental observation of jet quenching in ultra-relativistic heavy-ion collisions is one of the most remarkable discoveries at RHIC. High-p T hadron suppression, disappearance of back-to-back jets, and strong away-side modification at intermediate to low p T have provided us many insights into the matter created at RHIC. Particularly, angular correlations have become a powerful tool to study the QCD matter through its interactions with jets. Di-hadron correlations reveal significant broadening and softening of associated hadrons on the away side of a triggered high-p T particle. Many mechanisms have been proposed to accommodate the data, including the intriguing Mach cone shock waves in a thermalized hydrodynamic matter, which can be discriminated by 3-particle correlations. Here a brief overview of these remarkable experimental measurements on jet quenching is presented and implications of these measurements are discussed.

Transverse momentum and pseudo-rapidity density distributions of charged particles produced in pp and Au–Au collisions at $$\sqrt{{s}_{NN}}=200$$ GeV at RHIC

“…So, indirect signatures are used such as strangeness enhancement, di-lepton production, jet quenching, open charm enhancement and electromagnetic radiations. [7][8][9]. In order to have a deep understanding of the system created as a result of heavy-ion collisions, a comprehensive study of particle production and evolution of the system is required.…”

“…Therefore, the whole collision scenario is divided into different stages. These different stages involve hydrodynamic expansion of the system (bulk matter production), creation of QGP, and phase transition from QGP to hadronic phase [8][9][10]. In addition, kinetic and chemical freeze-outs are two important stages during the evolution of the heavy-ion collision systems.…”

“…In addition, kinetic and chemical freeze-outs are two important stages during the evolution of the heavy-ion collision systems. The system has a transition from QGP phase to hadronic matter at chemical freeze-out, and the transverse momentum ( p T ) spectra of produced particle are specified at the kinetic freeze-out [5,8,9]. QGP is not expected to be created in the small system (pp) with low multiplicity, due to very small density and volume of collision region.…”

“…On the basis of Bjorken estimation [12], it is believed that the energy density in the early stages of central Au-Au collisions at RHIC at 130 GeV and 200 GeV is sufficiently high to create a phase of deconfined matter (QGP) in the laboratory [6,13]. In heavy-ion collisions at RHIC, the first evidence of jet quenching was observed in 2003 in the STAR and PHENIX experiments [2,6,8,9]. The jet loses more energy as it was pushed further into the dense fireball of a heavy-ion collision − 30 to 50 times as dense as an ordinary nucleus.…”