Overview of the SiLC R&D Activities

The R&D Collaboration SiLC (Silicon tracking for Linear Colliders) is based on generic R&D aiming to develop the next generation of large Silicon tracking systems for the Linear collider experiments; it serves all three ILC detector concepts. There is a strong involvement in ILD, a natural collaboration with SiD and recent 4th concept interest to use Silicon tracking technology as well. Here is a very brief summary of the latest results on sensors, Front End Electronics, Mechanics and Integration issues, test bench and test beam results and where to go from there.Comment: 3 pages, 3 figures, LCWS08 Worksho

Level-1 pixel based tracking trigger algorithm for LHC upgrade

The Pixel Detector is the innermost detector of the tracking system of the Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collider (LHC). It precisely determines the interaction point (primary vertex) of the events and the possible secondary vertexes due to heavy flavours ($b$ and $c$ quarks); it is part of the overall tracking system that allows reconstructing the tracks of the charged particles in the events and combined with the magnetic field to measure their impulsion. The pixel detector allows measuring the tracks in the region closest to the interaction point. The Level-1 (real-time) pixel based tracking trigger is a novel trigger system that is currently being studied for the LHC upgrade. An important goal is developing real-time track reconstruction algorithms able to cope with very high rates and high flux of data in a very harsh environment. The pixel detector has an especially crucial role in precisely identifying the primary vertex of the rare physics events from the large pile-up (PU) of events. The goal of adding the pixel information already at the real-time level of the selection is to help reducing the total level-1 trigger rate while keeping an high selection capability. This is quite an innovative and challenging objective for the experiments upgrade for the High Luminosity LHC (HL-LHC). The special case here addressed is the CMS experiment. This document describes exercises focusing on the development of a fast pixel track reconstruction where the pixel track matches with a Level-1 electron object using a ROOT-based simulation framework.Comment: Submitted to JINST; 12 pages, 10 figures, Contribution to the JINST proceedings for the INFIERI2014 School in Paris, France, July 14-25, 201

Large Area Silicon Tracking: New Perspectives

The successful running of the large area Silicon trackers of ATLAS and CMS at LHC, and the ongoing R&D for the upgrade of these tracking systems, in various stages, over this decade, are a full proof of this technology and of its still impressive potential. The Linear Collider project is waiting for the possible discovery of a light Higgs at LHC maybe by end of 2012. These facts opened a new phase for the R&D on Silicon tracking for the Linear Collider, with enhanced synergy with LHC, Astrophysics and other HEP experiments, thus leading to new perspectives and alternatives.Comment: LCWS2011 Proceedings, 10 page

A new 130nm F.E readout chip for microstrip detectors

In the context of the Silicon tracking for a Linear Collider (SiLC) R&D collaboration, a highly compact mixed-signal chip has been designed in 130nm CMOS technology intended to read Silicon strip detectors for the experiments at the future International Linear Collider. The chip includes eighty eight channels of a full analog signal processing chain and analog to digital conversion with the corresponding digital controls and readout channels. The chip is 5x10mm2 where the analog implementation represents 4/5 of the total Silicon area.Comment: 3 pages, 4 figures, LCWS08 worksho

Pixel data real time processing as a next step for HL-LHC upgrades and beyond

The experiments at LHC are implementing novel and challenging detector upgrades for the High Luminosity LHC, among which the tracking systems. This paper reports on performance studies, illustrated by an electron trigger, using a simplified pixel tracker. To achieve a real-time trigger (e.g. processing HL-LHC collision events at 40 MHz), simple algorithms are developed for reconstructing pixel-based tracks and track isolation, utilizing look-up tables based on pixel detector information. Significant gains in electron trigger performance are seen when pixel detector information is included. In particular, a rate reduction up to a factor of 20 is obtained with a signal selection efficiency of more than 95\% over the whole $\eta$ coverage of this detector. Furthermore, it reconstructs p-p collision points in the beam axis (z) direction, with a high precision of 20 $\mu$m resolution in the very central region ($|\eta| < 0.8$), and, up to 380 $\mu$m in the forward region (2.7 $< |\eta| <$ 3.0). This study as well as the results can easily be adapted to the muon case and to the different tracking systems at LHC and other machines beyond the HL-LHC. The feasibility of such a real-time processing of the pixel information is mainly constrained by the Level-1 trigger latency of the experiment. How this might be overcome by the Front-End ASIC design, new processors and embedded Artificial Intelligence algorithms is briefly tackled as well.Comment: To be submitted to JHE

Measurement of the Lifetime Difference Between B_s Mass Eigenstates

We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion

Performance of a large scale prototype of the ATLAS accordion electromagnetic calorimeter

A 2 m long prototype of a lead-liquid argon electromagnetic calorimeter with accordion-shaped electrodes, conceived as a sector of the barrel calorimeter of the future ATLAS experiment at the LHC, has been tested with electron and pion beams in the energy range 10 to 287 GeV. A sampling term of 10%/root E(GeV) was obtained for electrons in the rapidity range 0 < eta < 1, while the constant term measured over an area of about 1 m(2) is 0.69%. With a cell size of 2.7 cm the position resolution is. about 4 mm/root E(GeV)