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This paper presents the first results from the ongoing research project HASPOC, developing a high assurance virtualization platform for the ARMv8 CPU architecture. Formal verification at machine code level guarantees information isolation between different guest systems (e.g. OSs) running on the platform. To use the platform in networking scenarios, we allow guest systems to securely communicate w
A new jet clustering algorithm-Arclus-is presented. The main difference between this and conventional algorithms is that while the latter in each step join two clusters into one,Arclus joins three clusters into two. The performance ofArclus in terms of the size of hadronization corrections is studied for some jet-reconstruction tasks ine+e− andep collisions, and is found to be as good as or, for s
The fourth version of the Ariadne program for generating QCD cascades in the colour dipole approximation is presented. The underlying physics issues are discussed and a manual for using the program is given together with a few sample programs.The major changes from previous versions are the introduction of photon radiation from quarks and inclusion of interfaces to the LEPTO and PYTHIA programs.
Virtual Compton scattering (VCS) on the proton has been studied at the Jefferson Laboratory using the exclusive photon electroproduction reaction ep→epγ. This paper gives a detailed account of the analysis which has led to the determination of the structure functions PLL-P TT/ε and PLT and the electric and magnetic generalized polarizabilities (GPs) αE(Q2) and βM(Q2) at values of the four-momentum
After a brief discussion of the statistics available to the four LEP experiments at the time of writing and an overview of B-event characteristics, the authors consider in particular the theory, practice and potential pitfalls of neural networks, a new approach to B tagging which attracted a great deal of interest. They then consider some of the QCD aspects of heavy flavour physics. Finally there
We present a toolkit, written in the C++ programming language, for event generation in high energy physics. The toolkit, called MC++, is an attempt to formulate the event generation chain in high in high energy p[article collisions in a transparent and generic way using object oriented programming techniques.
We present a model based upon string dynamics for the small x and large k⊥ parts of the structure functions of a hadron. These ocean partons are taken as those available in the virtual string states, which are resolved by the field pulse q, in case the process is considered as a measuring process. The resulting distributions will for sufficiently small x (x⩽O(Q−4)) behave as 1/x in case we use the
The use of Object Oriented Programming languages and techniques for the development of Monte Carlo simulators for particle production and decay is discussed. For illustration, two specific "template" programs are presented written in Objective-C and in C++, respectively
Using a neural-network classifier we are able to separate gluon from quark jets originating from Monte Carlo–generated e+e− events with 85%–90% accuracy.
We present results from Monte Carlo calculations of the string effect and the double inclusive correlation of particle flows for three-fold symmetric three-jet events in e+e− annihilation reactions at different energies. We find that the perturbative phase of the jet evolution quickly becomes dominant as energy increases.
We show that the hard qq̄ production is very sensitive to the details of the parton shower and that our treatment based on the dipole approximation gives significantly larger production than “conventional” parton showers. For our model we find qualitative agreement with experimental data for the Kπ ratio and D-meson production in high-pT jets.
We have searched for direct photons of low PT (≤1.0 GeV/c) at θc.m.=90° in pp collisions at √s =63 GeV. We used two independent methods: direct detection in NaI crystals and conversion to e+e− pairs. No signal is observed; the photon spectrum is well described by the decay of hadrons. The result is consistent with a direct low-PT photon signal reported at √s =12 GeV, but excludes a rapid growth of
We present a method to implement the gluon splitting process, g → QQ, into the dipole approximation to QCD cascades. It is known that due to the uncertainties in the interpolation between the pole regions, there are large uncertainties in the results. We show that there are further uncertainties due to the ordering in phase space of the gluon emission and gluon splitting processes. We present two
