The statistical bootstrap model

Abstract

A review is presented of the statistical bootstrap of Hagedorn and Frautschi. This is an attempt to apply the methods of statistical mechanics in high-energy physics, while treating all hadron states (stable or unstable) on an equal footing. A statistical calculation of the spectrum on this basis leads to an exponentially rising level density ρ(m) ~ cm-3 eβom at high masses. In the present work, explicit formulae are given for the asymptotic dependence of the level density on quantum numbers, in various cases. Hamer and Frautschi's for a realistic hadron spectrum is described. A statistical for hadron reactions is then put forward, analogous to the Bohr compound nucleus in nuclear physics, which makes use of this level density. Some general features of decay are predicted. The is applied to the process of NN annihilation at rest with overall success, and explains the high final state pion multiplicity, together with the low individual branching ratios into two-body final states, which are characteristic of the process. For more general reactions, the needs modification to take account of correlation effects. Nevertheless it is capable of explaining the phenomenon of limited transverse momenta, and the exponential decrease in the production frequency of heavy particles with their mass, as shown by Hagedorn. Frautschi's results on Ericson fluctuations in hadron physics are outlined briefly. The value of βo required in all these applications is consistently around [120 MeV]-1 corresponding to a resonance volume whose radius is very close to ƛπ. The construction of a multiperipheral cluster model for high-energy collisions is advocated.