67213603
A supercomputer for parallel data analysis
196032559
A VMEbus system controller
64925563
Universal CAMAC Branch Driver
62324462
The Data Acquisition of the Sphere 4$\pi$-Detector
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.
139621105
SPECTROMETER WITH SEMICONDUCTOR DETECTORS ONLINE WITH HP-2116B COMPUTER
122131877
Calculation of infrared-divergent Feynman diagrams with zero mass threshold
Abstract. Two-loop vertex Feynman diagrams with infrared and collinear divergences are investigated by two independent methods. On the one hand, a method of calculating Feynman diagrams from their small momentum expansion [1] extended to diagrams with zero mass thresholds [2] is applied. On the other hand, a numerical method based on a two-fold integral representation is used [3], [4]. The application of the latter method is possible by using lightcone coordinates in the parallel space. The numerical data obtained with the two methods are in impressive agreement.
12254630
Subleading Sudakov logarithms in electroweak processes
Abstract Recent results for the asymptotic behavior of fermion scattering amplitudes in the Sudakov limit are presented including next-to-leading logarithmic corrections. These are used for the analysis of the dominant electroweak corrections to the fermion-antifermion pair production in e+e−annihilation at high energy.
122046947
ARES — a spectrometer for the investigation of rare particle decays and rare nuclear processes
Abstract A magnetic spectrometer intended for a wide range of investigations of rare particle and nuclear processes is described. The spectrometer consists of cylindrical proportional chambers (∼ 15000 signal wires) with gas supply and gas leakage systems, cylindrical scintillation hodoscopes, a magnet, electronics with power supplies, and a data acquisition system. Basic characteristics of the spectrometer are discussed and results of first physics experiments are presented.
33580081
Iteration of planar amplitudes in maximally supersymmetric Yang-Mills theory at three loops and beyond
We compute the leading-color (planar) three-loop four-point amplitude of N = 4 supersymmetric Yang-Mills theory in 4 - 2{epsilon} dimensions, as a Laurent expansion about {epsilon} = 0 including the finite terms. The amplitude was constructed previously via the unitarity method, in terms of two Feynman loop integrals, one of which has been evaluated already. Here we use the Mellin-Barnes integration technique to evaluate the Laurent expansion of the second integral. Strikingly, the amplitude is expressible, through the finite terms, in terms of the corresponding one- and two-loop amplitudes, which provides strong evidence for a previous conjecture that higher-loop planar N = 4 amplitudes have an iterative structure. The infrared singularities of the amplitude agree with the predictions of Sterman and Tejeda-Yeomans based on resummation. Based on the four-point result and the exponentiation of infrared singularities, we give an exponentiated ansatz for the maximally helicity-violating n-point amplitudes to all loop orders. The 1/{epsilon}{sup 2} pole in the four-point amplitude determines the soft, or cusp, anomalous dimension at three loops in N = 4 supersymmetric Yang-Mills theory. The result confirms a prediction by Kotikov, Lipatov, Onishchenko and Velizhanin, which utilizes the leading-twist anomalous dimensions in QCD computed by Moch, Vermaseren and Vogt. Following similar logic, we are able to predict a term in the three-loop quark and gluon form factors in QCD.
119180405
Five-loop Konishi in N=4 SYM
Abstract We present a new method for computing the Konishi anomalous dimension in N = 4 SYM at weak coupling. It does not rely on the conventional Feynman diagram technique and is not restricted to the planar limit. It is based on the OPE analysis of the four-point correlation function of stress-tensor multiplets, which has been recently constructed up to six loops. The Konishi operator gives the leading contribution to the singlet SU ( 4 ) channel of this OPE. Its anomalous dimension is the coefficient of the leading single logarithmic singularity of the logarithm of the correlation function in the double short-distance limit, in which the operator positions coincide pairwise. We regularize the logarithm of the correlation function in this singular limit by a version of dimensional regularization. At any loop level, the resulting singularity is a simple pole whose residue is determined by a finite two-point integral with one loop less. This drastically simplifies the five-loop calculation of the Konishi anomalous dimension by reducing it to a set of known four-loop two-point integrals and two unknown integrals which we evaluate analytically. We obtain an analytic result at five loops in the planar limit and observe perfect agreement with the prediction based on integrability in AdS/CFT.