17086715
Finite temperature corrections in 2d integrable models
Abstract We study the finite size corrections for the magnetization and the internal energy of the 2d Ising model in a magnetic field by using transfer matrix techniques. We compare these corrections with the functional form recently proposed by Delfino and LeClair–Mussardo for the finite temperature behaviour of one-point functions in integrable 2d quantum field theories. We find a perfect agreement between theoretical expectations and numerical results. Assuming the proposed functional form as an input in our analysis we obtain a relevant improvement in the precision of the continuum limit estimates of both quantities.
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.
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)
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.
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.
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.
122908768
The Alice silicon pixel detector
CERN European Organization for Nuclear Research, CH-1211 Geneva 23, Switzerland Universita degli Studi di Padova, I-35131, Padova, Italy Dipartimento IA di Fisica e Sez. INFN di Bari, I-70126,Bari,Italy Comenius University, SK-84215 Bratislava, Slovakia NIKHEF, National Institute for Nuclear Physics and High Energy Physics, 1098 SJ Amsterdam, The Netherlands Slovak Academy of Sciences, SK-04353, Kosice, Slovakia Universita di Roma I, La Sapienza, I-00185, Roma, Italy
53308940
The ALICE silicon pixel detector readout electronics
Abstract The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the ALICE inner tracking system (ALICE Collaboration, 1999) [1] . The SPD is built with 120 detector modules (half-staves) and contains about 10 million pixels in total. The half-staves are connected to the off-detector electronics, housed in a control room 100 m away, via bidirectional optical links. The stream of data from the front-end electronics is processed in 20 VME readout modules, called routers, based on FPGAs. Three 2-channel link-receiver daughter cards, also based on FPGAs, are plugged in each router. Each link-receiver card receives data via the optical link from two half-staves, applies the zero suppression and passes them to the router to be processed and sent to the ALICE–DAQ system through the detector data link (DDL). The SPD control, configuration and data monitoring are performed using the VME interface embedded in the router.
111275354
Assembly procedure of the module (half-stave) of the ALICE Silicon Pixel Detector
The Silicon Pixel Detector (SPD) forms the two innermost layers of the ALICE Inner Tracking System (ITS). The detector includes 1200 readout ASICs, each containing 8192 pixel cells, bump-bonded to Si sensor elements. The thickness of the readout chip and the sensor element is 150 μm and 200 μm, respectively. Low-mass solutions are implemented for the bus and the mechanical support. In this contribution, we describe the basic module (half-stave) of the two SPD layers and we give an overview of its assembly procedure.
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.