Results from PHENIX at RHIC

TL;DR

This paper reports on PHENIX experiment results at RHIC, highlighting the suppression patterns of particles in heavy-ion collisions and discussing implications for quark mass and energy loss mechanisms in quark-gluon plasma.

Contribution

It presents new measurements of particle suppression in Au+Au collisions, challenging existing theories of parton energy loss and quark mass generation in quark-gluon plasma.

Findings

Equal suppression of pi0 and direct electrons in central Au+Au collisions

Results challenge radiative energy loss explanations

Implications for quark mass and QGP properties

Abstract

Results from PHENIX at RHIC in p-p and Au+Au collisions are presented from the perspective of measurements in p-p collisions at the CERN ISR which serve as a basis for many of the techniques used. Notable results include the equality of the suppression of inclusive pi0 and direct electrons (from the decay of heavy quarks) in the range of transverse momentuum 4 < pT < 9 GeV/c in central Au+Au collisions. This result appears to strongly disfavor the explanation of suppression as due to radiative energy loss of partons traversing a Quark Gluon Plasma but opens up a fundamental discussion of how Fermions get mass, whether all six quarks are nearly massless in a QGP and how to test this.