Network Growth with Feedback

Existing models of network growth typically have one or two parameters or strategies which are fixed for all times. We introduce a general framework where feedback on the current state of a network is used to dynamically alter the values of such parameters. A specific model is analyzed where limited resources are shared amongst arriving nodes, all vying to connect close to the root. We show that tunable feedback leads to growth of larger, more efficient networks. Exact results show that linear scaling of resources with system size yields crossover to a trivial condensed state, which can be considerably delayed with sublinear scaling.Comment: 4 pages, 4 figure

Synchronization methods for the PAC RPC trigger system in the CMS experiment

The PAC (pattern comparator) is a dedicated muon trigger for the CMS (Compact Muon Solenoid) experiment at the LHC (Large Hadron Collider). The PAC trigger processes signals provided by RPC (resistive plate chambers), a part of the CMS muon system. The goal of the PAC RPC trigger is to identify muons, measure their transverse momenta and select the best muon candidates for each proton bunch collision occurring every 25 ns. To perform this task it is necessary to deliver the information concerning each bunch crossing from many RPC chambers to the trigger logic at the same moment. Since the CMS detector is large (the muon hits are spread over 40 ns), and the data are transmitted through thousands of channels, special techniques are needed to assure proper synchronization of the data. In this paper methods developed for the RPC signal synchronization and synchronous transmission are presented. The methods were tested during the MTCC (magnet test and cosmic challenge). The performance of the synchronization methods is illustrated by the results of the tests

An RPC-based Technical Trigger for the CMS Experiment

In the CMS experiment, sub-detectors may send special trigger signals, called "Technical Triggers", for special purposes like test and calibration. The Resistive Plate Chambers are part of the Muon Trigger System of the experiment, but might also produce a cosmic muon trigger as Technical Trigger to be used during the commissioning to the detectors, the CMS magnet Test Cosmic Challenge and the later running of CMS. The proposed implementation is based on the development of a new board, the RBC Balcony Collector (RBC); the test results on prototypes and their performance during the recent CMS Cosmic Challenge are presented

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

The RPC system for the CMS experiment

The CMS experiment at the CERN Large Hadron Collider (LHC) is equipped with a redundant muon trigger system based on Drift Tubes Chambers (DT) and Cathode Strip Chamber (CSC), for the precise position measurement, and Resistive Plate Chambers (RPC), for the bunch crossing identification and a preliminary fast measurement of the muon transverse momentum. The CMS RPC system is constituted by 480 chambers in the barrel and 756 chambers in the forward corresponding to a total surface of about 3500 m2. The design and construction has involved many laboratories scattered all over the word. An accurate quality control procedure has been established at different levels of the production to achieve final detectors with operation parameters well inside the CMS specifications. In the summer 2006 a preliminary slice test involving a fraction of the CMS detector was performed. The performance of the RPC system with cosmic rays was studied versus the magnetic field using final running hardware and software protocols. Results on the RPC main working parameters are reported. © 2006 IEEE

The CMS experiment at the CERN LHC

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10(34)cm(-2)s(-1) (10(27)cm(-2)s(-1)). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4 pi solid angle. Forward sampling calorimeters extend the pseudo-rapidity coverage to high values (vertical bar eta vertical bar <= 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t

The CMS experiment at the CERN LHC

0info:eu-repo/semantics/publishe

CMS physics technical design report: Addendum on high density QCD with heavy ions

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies ,will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction - Quantum Chromodynamics (QCD) - in extreme conditions of temperature, density and parton momentum fraction (low-x). This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include "bulk" observables, (charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high pT hadrons which yield "tomographic" information of the hottest and densest phases of the reaction.0info:eu-repo/semantics/publishe