Collisions between Electrons and Nuclei

Abstract Not Provided

Bruno Touschek: particle physicist and father of the electron-positron collider

This article gives a brief outline of the life and works of the Austrian physicist Bruno Touschek, who conceived, proposed and, 50 years ago, brought to completion the construction of AdA, the first electron-positron storage ring. The events which led to the approval of the AdA pro ject and the Franco-Italian collaboration which con- firmed the feasibility of electron-positron storage rings will be recalled. We shall illustrate Bruno Touschek's formation both as a theoretical physicist and as an expert in particle accelerators during the period be- tween the time he had to leave the Vienna Staat Gymnasium in 1938, because of his Jewish origin from the maternal side, until he arrived in Italy in the early 1950s and, in 1960, proposed to build AdA, in Frascati. The events which led to Touschek's collaboration with Rolf Wideroe in the construction of the first European betatron will be de- scribed. The article will make use of a number of unpublished as well as previously unknown documents, which include an early correspon- dence with Arnold Sommerfeld and Bruno Touschek's letters to his family in Vienna from Italy, Germany and Great Britain. The impact of Touschek's work on students and collaborators from University of Rome will be illustrated through his work on QED infrared radiative corrections to high energy e+e- experiments and the book Meccanica Statistica.Comment: To be published in EPJ

Rapidity particle spectra in sudden hadronization of QGP

We show that the remaining internal longitudinal flow of colliding quarks in nuclei offers a natural explanation for the diversity of rapidity spectral shapes observed in Pb--Pb 158AGeV nuclear collisions. Thus QGP sudden hadronization reaction picture is a suitable approach to explain the rapidity spectra of hadrons produced.Comment: 3 pages including 2 figure

An extension of the Statistical Bootstrap Model to include Strangeness. Implications on Particle Ratios

The Statistical Bootstrap Model (SBM) is extended to describe hadronic systems which carry the quantum number of strangeness. The study is conducted in the three-dimensional space of temperature, up-down and strange chemical potentials, wherein the existence of a ``critical'' surface is established, which sets the limits of the hadronic phase of matter. A second surface, defined by the null expectation value of strangeness number is also determined. The approach of the latter surface to the critical one becomes the focal point of the present considerations. Two different versions of the extended SBM are examined, corresponding to the values 2 and 4 for the exponent, which determines the asymptotic fall-off of the mass spectrum. It is found that the version with the value 4 has decisive physical advantages. This model is subsequently adopted to discuss (strange) particle ratios pertaining to multiparticle production processes, for which a thermal equilibrium mode of description applies.Comment: 29 pages, 38 figures, all the figures are joined in one file. accepted for publication in Phys. Rev.

Covariant statistical mechanics

1. The relativistic t ransformation properties of thermodynamical quantities have been discussed even before the advent of the special theory of relativity. In 1904 HASENOEHRL (1) derived a formula for the spectral intensi ty of the radiation emit ted from a moving black body. By 1919 the problem seemed to be solved and clearly understood: a chapter in Pauli 's (2) Relativltdtstheorie is dedicated to this question. The classical opinion can be memorized by stating tha t according to it the ideal gas equation (in which the pressure is considered to be a scalar) is form-invariant , so tha t the temperature has to transform like a volume: it is smaller in the moving frame than in the rest frame of the system. This opinion was challenged in 1963 by OTT (3), who held tha t the temperature should increase in the transition from the' rest system to a moving frame. There followed an extensive discussion which is admirably documented in Moller's (4) article with the significant title: Relat iwst ic Thermodynamics