121606160
Operator product expansion in the Weinberg renormalization scheme and factorization
Abstract The operator product expansion (OPE) is derived in the framework of the Weinberg renormalization 3cheme [1]. The coefficient functions of the OPE are explicitly expressed in terms of certain Green functions. The OPE provides factorization, i.e. separation of large and small distances.
120159616
Evaluation of three-loop feynman diagrams by four-dimensional integration by parts and differential renormalization
Four-dimensional integration by parts, combined with differential renormalization, is applied to evaluate three-loop Feynman diagrams.
15966773
Fermionic contributions to the three-loop static potential
Abstract We consider the three-loop corrections to the static potential which are induced by a closed fermion loop. For the reduction of the occurring integrals a combination of the Grobner and Laporta algorithm has been used and the evaluation of the master integrals has been performed with the help of the Mellin–Barnes technique. The fermionic three-loop corrections amount to 2% of the tree-level result for top quarks, 8% for bottom quarks and 27% for the charm quark system.
41885673
Quark and gluon form factors to three loops.
We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs-boson and two gluons to three-loop order within massless perturbative quantum chromodynamics. These results provide building blocks for many third-order cross sections. Furthermore, this is the first calculation of complete three-loop vertex corrections.
119544460
Two-Loop Electroweak Logarithms
We present the complete analytical result for the two-loop logarithmically enhanced contributions to the high energy asymptotic behavior of the vector form factor and the four-fermion cross section in a spontaneously broken SU(2) gauge model. On the basis of this result we derive the dominant two-loop electroweak corrections to the neutral current four-fermion processes at high energies.
2365986
FIESTA 2: Parallelizeable multiloop numerical calculations
Abstract The program FIESTA has been completely rewritten. Now it can be used not only as a tool to evaluate Feynman integrals numerically, but also to expand Feynman integrals automatically in limits of momenta and masses with the use of sector decompositions and Mellin–Barnes representations. Other important improvements to the code are complete parallelization (even to multiple computers), high-precision arithmetics (allowing to calculate integrals which were undoable before), new integrators, Speer sectors as a strategy, the possibility to evaluate more general parametric integrals. Program summary Program title: FIESTA 2 Catalogue identifier: AECP_v2_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AECP_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL version 2 No. of lines in distributed program, including test data, etc.: 39 783 No. of bytes in distributed program, including test data, etc.: 6 154 515 Distribution format: tar.gz Programming language: Wolfram Mathematica 6.0 (or higher) and C Computer: From a desktop PC to a supercomputer Operating system: Unix, Linux, Windows, Mac OS X Has the code been vectorised or parallelized?: Yes, the code has been parallelized for use on multi-kernel computers as well as clusters via Mathlink over the TCP/IP protocol. The program can work successfully with a single processor, however, it is ready to work in a parallel environment and the use of multi-kernel processor and multi-processor computers significantly speeds up the calculation; on clusters the calculation speed can be improved even further. RAM: Depends on the complexity of the problem Classification: 4.4, 4.12, 5, 6.5 Catalogue identifier of previous version: AECP_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 735 External routines: QLink [1], Cuba library [2], MPFR [3] Does the new version supersede the previous version?: Yes Nature of problem: The sector decomposition approach to evaluating Feynman integrals falls apart into the sector decomposition itself, where one has to minimize the number of sectors; the pole resolution and epsilon expansion; and the numerical integration of the resulting expression. Solution method: The sector decomposition is based on a new strategy as well as on classical strategies such as Speer sectors. The sector decomposition, pole resolution and epsilon-expansion are performed in Wolfram Mathematica 6.0 or, preferably, 7.0 (enabling parallelization) [4]. The data is stored on hard disk via a special program, QLink [1]. The expression for integration is passed to the C-part of the code, that parses the string and performs the integration by one of the algorithms in the Cuba library package [2]. This part of the evaluation is perfectly parallelized on multi-kernel computers. Reasons for new version: 1. The first version of FIESTA had problems related to numerical instability, so for some classes of integrals it could not produce a result. 2. The sector decomposition method can be applied not only for integral calculation. Summary of revisions: 1. New integrator library is used. 2. New methods to deal with numerical instability (MPFR library). 3. Parallelization in Mathematica . 4. Parallelization on multiple computers via TCP-IP. 5. New sector decomposition strategy (Speer sectors). 6. Possibility of using FIESTA to for integral expansion. 7. Possibility of using FIESTA to discover poles in d. 8. New negative terms resolution strategies. Restrictions: The complexity of the problem is mostly restricted by CPU time required to perform the evaluation of the integral Running time: Depends on the complexity of the problem References: [1] http://qlink08.sourceforge.net , open source. [2] http://www.feynarts.de/cuba/ , open source. [3] http://www.mpfr.org/ , open source. [4] http://www.wolfram.com/products/mathematica/index.html .
109801893
Development of a data acquisition system for the SPHERE spectrometer
Abstract The 4π-detector SPHERE for studying multiple particle cumulative production is currently under construction at the Laboratory of High Energies, JINR, Dubna. This paper briefly describes the present status and future developments of the data acquisition system for this setup. A multiprocessor system based on VMEbus will be implemented for parallel readout, event-building, and data preprocessing. A workstation will be used for data analysis and experimental control. The investigation has been performed at the Laboratory of High Energies, JINR.
64925563
Universal CAMAC Branch Driver
122167405
A coding and reading data unit from hodoscopic recording systems in the CAMAC standard
Abstract A coding and reading data unit from any CAMAC hodoscopic recording system is described.
124769212
Method of Bunch Phase Distribution Measurement Based on a Møller Scattering
121235164
Architecture of data-acquisition systems for high-energy physics experiments
In this review we discuss the evolution of the basic principles of the architecture of data-acquisition systems for experimental setups used in high-energy physics and relativistic nuclear physics during the last 25 years. The effect of the latest advances in computational techniques and communications, such as microprocessors and open bus system standards, on improving data recording and acquisition is discussed. The evolution of data-acquisition systems is illustrated by examples of developments occurring at the leading physics centers and at the Laboratory of High Energy Physics, JINR, Dubna. The trends in the future development of data-acquisition systems are described for the research programs at the LHCcollider, CERN, and the Relativistic Heavy Ion Collider at Brookhaven National Laboratory.