Ioannis Evangelou

Multiplicity distributions in different pseudorapidity intervals at a CMS energy of 540 GeV

Abstract Multiplicity distributions of charged particles for inelastic, non single-diffractive events in proton-antiproton collisions at a centre of mass energy of 540 GeV are presented for various pseudorapidity (Δη) intervals. The widths of the multiplicity distributions, scaled to their means, increase as Δη is made smaller, and the deviation from a Poisson distribution becomes progressively more pronounced. It is found that the data are remarkably well described by a negative binomial distribution. The parameters of the distributions vary smoothly with the size of the acceptance interval.

Scaling of Pseudorapidity Distributions at c.m. Energies up to 0.9 TeV

AbstractNew data are presented on charged particle pseudorapidity distributions for inelastic events produced at c.m. energies

A new empirical regularity for multiplicity distributions in place of KNO scaling

\sqrt s

First measurement of the π+π- atom lifetime

=200 and 900 GeV. The data were obtained at the CERN antiproton-proton Collider operated in a new pulsed mode. The rise of the central density ρ(0) at energies up to

Production of photons and search for Centauro events at the SPS collider

\sqrt s

\bar{p} p

=900 GeV has been studied. A new form of central region scaling is found involving the densityρn(0) for charged multiplicityn, namely that the scaled central densityρn(0)/ρ(0) expressed as a function ofz=n/〈n〉 is independent ofs. Scaling in the fragmentation region holds to 10–20%, and the small amount of scalebreaking observed here could be accommodated within the framework suggested by Wdowcyk and Wolfendale to account for both accelerator and cosmic ray data.