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)
14449698
Deconfinement transition and dimensional cross-over in the 3D gauge Ising model
We present a high-precision Monte Carlo study of the finite-temperature Z2 gauge theory in 2 + 1 dimensions. The duality with the 3D Ising spin model allows us to use powerful cluster algorithms for the simulations. For temporal extensions of up to Nt = 16 we obtain the inverse critical temperature with a statistical accuracy comparable with the most accurate results for the bulk phase transition of the 3D Ising model. We discuss the predictions of T.W. Capehart and M.E. Fisher for the dimensional cross-over from 2 to 3 dimensions. Our precise data for the critical exponents and critical amplitudes confirm the Svetitsky-Yaffe conjecture. We find deviations from Olesen's prediction for the critical temperature of about 20%.
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.
119182609
Integrable structures in LGTs near the deconfinement transition
In this contribution we review some recent results about the emergence of 2D integrable systems in 3D Lattice Gauge Theories near the deconfinement transition. We focus on some concrete examples involving the flux tube thickness, the ratio of k-string tensions and Polyakov loops correlators in various models.
204930044
Width of Long Colour Flux Tubes in Lattice Gauge Systems
In the confining phase of any gauge system the mean squared width of the colour flux tube joining a pair of quarks should grow logarithmically as a function of their distance, according to the effective string description of its infrared properties. New data on 3D Z_2 gauge theory, combined with high precision data on the interface physics of the 3D Ising model fit nicely this behaviour over a range of more than two orders of magnitude.
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.
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.
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.
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