10634649
The Kazakov-Migdal model as a high temperature lattice gauge theory
Abstract We show that the Kazakov-Migdal (KM) induced gauge model d dimensions describes the high temperature limit of ordinary lattice gauge theories in d +1 dimensions. The matter fields are related to the Polyakov loops, while the spatial gauge variables become the gauge fields of the KM model. This interpretation of the KM model is in agreement with some recent results in high temperature lattice QCD.
17385077
Critical amplitudes and mass spectrum of the 2d Ising model in a magnetic field
Abstract We compute the spectrum and several critical amplitudes of the two-dimensional Ising model in a magnetic field with the transfer matrix method. The three lightest masses and their overlaps with the spin and the energy operators are computed on lattices of a width up to L 1 =21 . In extracting the continuum results we also take into account the corrections to scaling due to irrelevant operators. In contrast with previous Monte Carlo simulations our final results are in perfect agreement with the predictions of S-matrix and conformal field theory. We also obtain the amplitudes of some of the subleading corrections, for which no S-matrix prediction has yet been obtained.
204925001
Critical Boundary Conditions for the Effective String
Gauge systems in the confining phase induce constraints at the boundaries of the effective string, which rule out the ordinary bosonic string even with short distance modifications. Allowing topological excitations, corresponding to winding around the colour flux tube, produces at the quantum level a universal free fermion string with a boundary phase nu=1/4. This coincides with a model proposed some time ago in order to fit Monte Carlo data of 3D and 4D Lattice gauge systems better. A universal value of the thickness of the colour flux tube is predicted.
2604312
Static quark potential and effective string corrections in the (2+1)-d SU(2) Yang-Mills theory
We report on a very accurate measurement of the static quark potential in SU(2) Yang-Mills theory in (2+1) dimensions in order to study the corrections to the linear behaviour. We perform numerical simulations at zero and finite temperature comparing our results with the corrections given by the effective string picture in these two regimes. We also check for universal features discussing our results together with those recently published for the (2+1)-d (2) and SU(3) pure gauge theories.
209832724
Thermal operators in Ising percolation
We discuss a new cluster representation for the internal energy and the specific heat of the d -dimensional Ising model, obtained by studying the percolation mapping of an Ising model with an arbitrary set of antiferromagnetic links. Such a representation relates the thermal operators to the topological properties of the Fortuin-Kasteleyn (FK) clusters of Ising percolation and is a powerful tool to get new exact relations on the topological structure of FK clusters of the Ising model defined on an arbitrary graph.
204927457
Some universal features of the effective string picture of pure gauge theories
The effective string describing the large distance behaviour of the quark sources of gauge field theories in the confining phase in D=3 or D=4 space-time dimensions can be formulated, in the infrared limit, as a suitable 2D conformal field theory on surfaces with quark loops as boundaries. Recent results on self-avoiding random surfaces allow to fix almost uniquely such a conformal theory. As a consequence, some universal relationships among the string tension , the thickness of the colour flux tube, the deconfinement temperature and a lower bound of the glueball mass spectrum are found. The general agreement with the data extracted from recent lattice simulations with different gauge groups is rather impressive.(Talk held by F.Gliozzi at Lattice'92 , Amsterdam)
109085314
The silicon pixel detector (SPD) for the ALICE experiment
The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the inner tracking system (ITS). The basic building block of the SPD is the half-stave carrying two detector ladders. The half-stave is equipped with a multi-chip module (MCM) and an optical fibre link for control and readout. A 5-layer aluminium/polyimide bus ensures the distribution of power and signals on each half-stave. The half-staves are mounted on a light-weight carbon-fibre structure with an integrated evaporative cooling system. An overview of the SPD development and the current status of the construction are presented.
109039717
Test beam performance of the ALICE silicon pixel detector
Abstract The ALICE Silicon Pixel Detector (SPD) will include 1200 bump-bonded readout chips produced in a commercial 0.25 μ CMOS process. Each chip has 8192 pixels of size 50 × 425 μ m 2 , which leads to about 10 million readout channels in the whole detector system. Test beam measurements were recently carried out at the CERN SPS using a positive proton/pion beam as well as a 158 A GeV/c heavy ion beam (In) with a fixed Pb target. Analysis show good performance of the ALICE chip and assemblies in the positive beam as well as in the high multiplicity In beam. Preliminary results from data analysis show good performance of the SPD and fulfill the ALICE requirements.
121671017
Recent test results of the ALICE silicon pixel detector
The ALICE SPD (Silicon Pixel Detector) forms the two innermost layers of the Inner Tracking System (ITS) of the ALICE experiment at LHC. After several years of development the production of the modules is starting. The present article provides an overview of the different elements that will be used in the SPD with special emphasis given to testing of wafers and bump-bonded ladders.
6726038
The ALICE Pixel Detector Readout Chip Test System
The ALICE experiment will require some 1200 Readout Chips for the construction of the Silicon Pixel Detector [1] and it has been estimated that approximately 3000 units will require testing. This paper describes the system that was developed for this task.