David E. Kahana

Collective flow from the intranuclear cascade model

The phenomenon of collective flow in relativistic heavy ion collisions is studied using the hadronic cascade model ARC. Comparison is made to data for Au+Au at {ital p}=1.7 GeV/{ital c}, and for Ar+Pb at {ital p}=1.4 GeV/{ital c}. Collective flow is well described quantitatively without the need for explicit mean field terms to simulate the nuclear equation of state. Pion collective flow is in the opposite direction to nucleon flow, as is that of antinucleons and other produced particles. Pion and nucleon flow are predicted at BNL Alternating Gradient Synchrotron energies also, where, in light of the higher baryon densities achieved, we speculate that equation of state effects may be observable.

Diquark bosonisation of the Nambu model

Abstract A U(1) × U(1) chirally symmetric version of the Nambu-Jona-Lasinio model with scalar and vector interactions, is rewritten in diquark and meson variables. Integration over the quark fields yields the bosonised) effective action for diquarks and mesons. For small values of the vector coupling, the bosonised action exhibits spontaneous breaking of chiral symmetry. For sufficiently large values of the vector coupling, however, a diquark condensate forms instead, and colour symmetry is spontaneously broken.

On the Pauli-Villars regularisation scheme in the NJL model

Abstract We consider the Nambu-Jona-Lasinio model with a Pauli-Villars cutoff. We point out that previous attempts to use this regularisation have not been consistent and it is shown that if used correctly this approach yields very reasonable values for the cutoff parameter and quark condensate when we demand that ƒπ is fixed to its experimental value. Finally it is argued that because of its covariance and smooth nature this regularisation scheme has significant advantages over other regulators on the market.

P ANNIHILATION IN AU + AU AT 11 GEV/C. AUTHORS' REPLY

Antinucleon production in heavy ion collisions is potentially an excellent signal for unusual phenomena in hot and dense matter. However, at the low energies available at the AGS the annihilation process must be handled with care. In this Comment, we consider the case of Au + Au collisions at approximately 11 GeV/c, applying the ARC treatment of pbar production and annihilation to the analysis of experiment E878. It is apparent that classical screening introduced for Si + Au is crucial in the understanding of data obtained with the more massive projectile. Unfortunately, there seems no necessity for invoking unusual behaviour in the Au + Au system.

Proportionally off-mass-shell equation for unequal mass systems

A new two-body relativistic equation is presented. The major advantage of the proposed equation over existing equations in the literature is that this equation automatically adjusts itself for different mass systems. Besides unitarity and covariance, this equation gives a physically meaningful prescription of how the particles go off-mass-shell in the intermediate states. It allows the particles to go off-mass-shell proportionally to their masses so that when one of the masses becomes infinite, it automatically becomes a one-body equation for the lighter particle and for equal mass systems, it reduces to the Todorov equation. Because of the off-mass-shell prescription for the intermediate states, it will be useful for systems with a wide variety of masses such as mesons, positronium, muonium, pionium, the deuteron and light hadronic atoms.

Top quark and Higgs boson masses in dynamical symmetry breaking

A model for composite electroweak bosons is reexamined to establish approximate ranges for the initial predictions of the top quark and Higgs boson masses. Higher order corrections to this four-fermion theory at a high mass scale, where the theory is matched to the standard model, have little effect, as do wide variations in this scale. However, including all one loop evolution and defining the masses self-consistently, at their respective poles, shifts the top quark and Higgs boson masses somewhat from the earlier calculated positions. These masses exhibit a moderate dependence on the measured strong coupling: for example, with {alpha}{sub {ital S}}({ital m}{sub {ital W}})=0.115(0.125), one finds {ital m}{sub {ital t}}{similar_to}180(185) GeV and {ital m}{sub {ital H}}{similar_to}130(135) GeV.

Meson and Baryon structure in the U(N)⊗U(N) symmetric Nambu-Jona-Lasinio model

Abstract A one-loop effective largrangian for the U( N )×U( N ) symmetric Nambu-Jona-Lasinio model is constructed by expanding the fermion determinant around the spontaneously broken vacuum. Kinetic and mass terms for scalar and pseudoscalar mesons are obtained via the derivative expansion. In the large cutoff limit, the effective lagrangian reduces to the linear σ-model. The implied quark-meson coupling generates soliton-like bound states for baryons. Meson masses are calculated explicitly for the U(3) case, and an estimate is obtained for the nucleon mass.

Energies and Regge trajectories from two‐body relativistic bound state equations with quark confining interaction

Lattice gauge calculations have shown that the interaction between quarks is described by a Linear potential at large distances. Quarks in hadrons are only properly described by two‐body relativistic bound state equations [1,2] which are most easily solved in momentum space. However the Linear potential leads to singularities in momentum space [3]. We show how to obtain exact solution the Schrodinger equation using a subtraction procedure to handle the singularities. This is generalized to a relativistic kernel by replacing 3‐vectors with 4‐vectors. We solve six different 3‐dimensional reductions of the Bethe‐Salpeter equation (BSE) by using a subtraction procedure tailored to the relativistic kernels.

{ovr {ital p}} Annihilation in Au+Au at 11GeV/{ital c}

Antinucleon production in heavy ion collisions is potentially an excellent signal for unusual phenomena in hot and dense matter. However, at the low energies available at the AGS the annihilation process must be handled with care. In this Comment, we consider the case of Au + Au collisions at approximately 11 GeV/c, applying the ARC treatment of pbar production and annihilation to the analysis of experiment E878. It is apparent that classical screening introduced for Si + Au is crucial in the understanding of data obtained with the more massive projectile. Unfortunately, there seems no necessity for invoking unusual behaviour in the Au + Au system.

Pbar Annihilation in Au+Au at AGS Energies

Antinucleon production in heavy ion collisions is potentially an excellent signal for unusual phenomena in hot and dense matter. However, at the low energies available at the AGS the annihilation process must be handled with care. In this Comment, we consider the case of Au + Au collisions at approximately 11 GeV/c, applying the ARC treatment of pbar production and annihilation to the analysis of experiment E878. It is apparent that classical screening introduced for Si + Au is crucial in the understanding of data obtained with the more massive projectile. Unfortunately, there seems no necessity for invoking unusual behaviour in the Au + Au system.