Study of pp and ΛΛ production in π±p reactions at 18.5 GeV/c

Studies have been made of the rare reactions $\text{π}{}^{\mathrm{+}}\text{p}\text{→ π}{}^{\mathrm{+}}\text{pp}\text{p}$ and $\text{Λ +}\text{Λ}\text{+}\text{anything}$, and of $\text{π}{}^{\mathrm{?}}\text{p}\text{→ π}{}^{\mathrm{?}}\text{pp}\text{p}$ and $\text{Λ +}\text{Λ}\text{+}\text{anything}$, with cross sections of 18.5 ± 5.5, 10.7 ± 3.0, 12.0 ± 5.0, and 19.7 ± 4.8 μb, respectively. Production characteristics of these reactions are examined and effective-mass spectra are presented. There is no significant evidence in the data for production of Ψ(3095) in the baryon-antibaryon system, or for any other high-mass resonances.     

Inclusive reactions: A new parametrization

We have fitted the π^? spectra from the reactions π^±p → π^?+ anything using an expression which exhibits the differing forward-backward slopes of the x-distributions, the turnover near (but not exactly at) x = 0 and the correlations between P₁ and p²_T. The expression is a generalized Bose-Einstein distribution which is covariant with respect to Lorentz transformation along the incident beam direction.     

PRESSURE-VELOCITY EQUILIBRIUM HYDRODYNAMIC MODELS

This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.