Regular Series


Vol. 18 (1987), No. 6, pp. 519 – 597


The Spectrum of Quantum Chromodynamics: A New Approach to Lattice Computation of Quark Propagators

abstract

A new method of computing quark propagators on a lattice is developed. It reduces the four-dimensional problem to the series of inversions of the two-dimensional fermionic matrices. The technique is applied to compute chiral properties of quantum chromodynamics, and to obtain masses of the lowest lying hadrons.


Transverse Hydrodynamics with a First Order Phase Transition in Very High Energy Nuclear Collisions

abstract

The hydrodynamic treatment of the central region of ultrarelativistic nuclear collisions using the bag model equation of state and assuming a smooth phase transition through equilibrium mixed phase, is reviewed together with the calculation of transverse momentum distributions of hadrons, dilepton spectra and the kinetic evolution of strangeness. Transverse collective flow leads to distinct features in the hadron and dilepton spectra. To study the flow, the events must be sampled according to their multiplicity, which essentially fixes the initial conditions for the flow. The transverse momenta of the hadrons show clear correlations with the equation of state. Boost invariant longitudinal expansion leads to fast cooling of plasma and strong reduction of the average transverse momentum of hadrons. It is argued that the highest values of transverse momenta which are reported from the cosmic ray experiment, are not easily understood to be of thermal origin. Dilepton spectra in the mass range of a few GeV may offer a possibility to get experimental information on the initial temperature of the matter. Strangeness abundance is argued to be insensitive on the initial temperature of the plasma, but may offer a way of determining the critical temperature.


Multiplicity Distribution in Central Rapidity Region of Nuclear Collisions and the Wounded Nucleon Model

abstract

Wounded nucleon model is used to estimate the multiplicity distributions of charged particles produced in central rapidity region \(|y| \leq 0.5\) of the collisions of 200 GeV \(^{16}\)O nuclei with heavy targets. The results show marked differences with estimates from production of quark–gluon plasma.


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