P. Hanke

A measurement of p̄p and pp elastic scattering at ISR energies

We have measured the differential cross section for pp and pp elastic scattering at √s = 31, 53 and 62 GeV in the interval 0.05 < |t| < 0.85 GeV2 at the CERN ISR using the Split Field Magnet detector. At 53 and 62 GeV, for 0.17 < |t| < 0.85 GeV2 both pp and pp data show simple exponential behaviour in t; at √s = 31 GeV the data for 0.05 < |t| < 0.85 GeV2 are consistent with a change in slope near |t| = 0.15 GeV2.

A measurement of the inclusive cross section of charged pions at very high transverse momenta

Abstract The inclusive cross sections for the production of high transverse momentum π + and π − mesons in proton-proton interactions have been measured at the highest ISR energy √ s = 63 GeV and at a c.m. production angle of 50°. The cross sections for π + and π − mesons are compared as a function of transverse momentum. It is shown that the inclusive cross section of π − mesons decreases faster than the π + cross section. particle σ ( π ± )/ σ (charged particles) are presented as a function of transverse momentum.

A diquark scattering model for highp T proton production inpp collisions at the ISR

The relative yield of high transverse momentum protons measured inpp interctions at the CERN ISR is calculated in the framework of simple parton models. Whereas models based exclusively on quark and gluon scattering fail to describe the data, the hypothesis of diquark scattering provides a quantitative understanding of the measured dependences on transverse momentum, polar angle, and centre-of-mass energy. Different assumptions on diquark structure functions are tested.

Use of an FPGA to identify electromagnetic clusters and isolated hadrons in the ATLAS level-1 calorimeter trigger

Abstract At the full LHC design luminosity of 10 34 cm −2 s −1 , there will be approximately 10 9 proton–proton interactions per second. The ATLAS level-1 trigger is required to have an acceptance factor of ∼10 −3 . The calorimeter trigger covers the region | η |⩽5.0, and φ =0 to 2 π . The distribution of transverse energy over the trigger phase space is analysed to identify candidates for electrons/photons, isolated hadrons, QCD jets and non-interacting particles. The Cluster Processor of the level-1 calorimeter trigger is designed to identify transverse energy clusters associated with the first two of these. The algorithms based on the trigger tower energies which have been designed to identify such clusters, are described here. The algorithms are evaluated using an FPGA. The reasons for the choice of the actual FPGA being used are given. The performance of the FPGA has been fully simulated, and the expected latency has been shown to be within the limits of the time allocated to the cluster trigger. These results, together with the results of measurements made with real data into a fully configured FPGA, are presented and discussed.

Multiplicity dependence of the average transverse momentum and of the particle source size inp−p interactions at\(\sqrt s \)=62, 44 and 31 GeV

AbstractThe average transverse momentum and the size of the particle emitting source (measured via Bose-Einstein correlations) have been studied as functions of the charged particle density in the central region inp-p interactions at

Charged particle spectra in αα and αp collisions at the CERN ISR

\sqrt s

Momentum distributions of nuclear fragments in αα collisions at √s = 125 GeV

=62, 44 and 31 GeV. Both the average transverse momentum and the source size increase with increasing density at all three energies. This effect, very weak at