EDUCATION:

Ph.D. 1974, University of California, Berkeley

RESEARCH:

I head the nuclear theory group at Columbia. Our work concentrates on the physics of ultra-dense nuclear matter, called the quark-gluon plasma. Current experiments at the Relativistic Heavy Ion Collider RHIC at BNL require the development of detailed parton/ hadron transport theory in order to interpret the data and to test specific signatures that can reveal the physical properties of this new state of matter. We have developed new techniques to solve ultra-relativistic non-linear Boltzmann equations and relativistic hydrodynamics to study collective flow signatures, such as elliptic transverse flow at RHIC. In addition, these transport models are used to predict pion interferometry correlations that probe the global freeze-out space-time geometry of high energy nuclear reactions. Recently we concentrate on the problem of non-abelian radiative energy loss and its application as a novel tomographic tool to study the density evolution in the expanding gluon plasma on times scales ~10^-23 sec. We predicted that high transverse momentum jets of hadrons produced in nuclear reactions should be strongly quenched by radiative energy loss induced by the high opacity of the produced plasma. This prediction has been recently confirmed by the PHENIX and STAR experiments at RHIC, and we have deduced from the quenching pattern that gluon densities about 100 times greater than in ground state nuclei have been attained in Au+Au reactions at Ecm = 200 AGeV. At such high densities matter is predicted via lattice QCD to be in the deconfined phase. We continue to refine and extend the theory of jet tomography in order to predict the quenching pattern of heavy quarks as well as high pT correlations of monojets. Another area of interest is the dynamics of baryon number transport and hyperonization at RHIC. Preliminary data provide possible evidence of novel topological gluon junction dynamics that we first tested on data at lower SPS/CERN energies.

SELECTED PUBLICATIONS:

For a complete listing of publications see SPIRES.

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