Recombination and Fragmentation of Hadrons from a Dense
Parton Phase
Rainer J. Fries
School of Physics and Astronomy,
University of Minnesota
Recent experimental results from RHIC show strong energy loss of jets
in the hot nuclear medium. There are indications that this strong
quenching effect of hard QCD processes could lead to the domination of
"soft" thermal hadron production up to surprisingly high values
of PT.
We argue that hadron production in this kinematic domain can be described
by recombination of quarks from an expanding thermal parton phase, going
over
into the usual fragmentation picture at larger transverse momentum.
This
provides a very good description of the available data on hadron
production from RHIC, including all hadron species. In turn, surprising
new effects show up, like the fact that the number of valence quarks
inside a hadron is a direct observable at RHIC.