The CMS Drift Tube Trigger Track Finder

Muons are among the decay products of many new particles that may be discovered at the CERN Large Hadron Collider. At the first trigger level the identification of muons and the determination of their transverse momenta and location is performed by the Drift Tube Trigger Track Finder in the central region of the Compact Muon Solenoid experiment, using track segments detected in the Drift Tube muon chambers. Track finding is performed both in pseudorapidity and azimuth. Track candidates are ranked and sorted, and the best four are delivered to the subsequent high level trigger stage. The concept, design, control and simulation software as well as the expected performance of the system are described. Prototyping, production and tests are also summarized

Proton reconstruction with the CMS-TOTEM Precision Proton Spectrometer

The Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb-1 in proton-proton (pp) collisions at the LHC at 13 TeV (Run 2). This paper describes the key features of the PPS alignment and optics calibrations, the proton reconstruction procedure, as well as the detector efficiency and the performance of the PPS simulation. The reconstruction and simulation are validated using a sample of (semi)exclusive dilepton events. The performance of PPS has proven the feasibility of continuously operating a near-beam proton spectrometer at a high luminosity hadron collider

Conceptual Design of HO Scintillators in the RPC Muon Trigger

HO scintillators located around the CMS coil are sensitive to muons. They can be used in coincidence with RPC chambers for the Muon Trigger. This note contains a brief description of the two systems and the proposal of how they can be integrated. It serves as the interface specification. Backgrounds, efficiencies, and trigger rates have been calculated. The conclusion is that rate reduction factors as high as 100 can be obtained with a sim 90 % efficient confirmation requirement

Test Beam Analysis of the First CMS MB2 Drift Tube Muon Chamber

In october 2001 the first MB2 DT chamber, produced at Madrid, was tested at the CERN Gamma Irradiation Facility (GIF) using a muon beam. A RPC structure was attached to the top of the chamber, and operated coupled together for the first time. The performance of the DT chamber was studied for several operating conditions, and for gamma rates similar to the ones expected at the LHC. In addition, part of the associated readout electronics was tested using a beam with the same LHC bunch structure. The purpose was to validate the present design for the Read Out Board (ROB) and high performance TDC (HPTDC) chips. This note presents our analysis of the data. The results in all cases are considered satisfactory

Influence of Misalignment Scenarios on Muon Reconstruction

This note summarizes different studies on the degradation of the muon reconstruction performance due to non-perfect alignment of Muon System and Tracker of CMS. Several misalignment scenarios, from start-of-run to full alignment with data, are considered and performances studied for both on-line trigger and off-line reconstruction in single muon and dimuon samples

Fine synchronization of the muon drift tubes local trigger

The CMS muon trigger, based on self-triggering arrays of drift tubes, is able to perform the identification of the muon parent bunch crossing using a rather sophisticated algorithm. The identification is unique only if the trigger chain is correctly synchronized. Some test beam time was devoted to take data useful to investigate the solutions to the problem of the synchronization of the trigger electronics with the machine clock. Possible alternatives were verified and dependence on muon track properties were studied

Further Tests of the CMS Drift Tubes Muon Trigger

Two drift tubes stations of the CMS muon barrel system were exposed, in October 2004, to a 40 MHz bunched muon beam at the Cern SpS. The performances of the level-1 local trigger were tested at different energies and inclination angles of the incident muon beam. Data with and without an iron absorber placed between the two stations were also collected, to simulate the electromagnetic shower development in CMS. In addition special data-taking runs were dedicated to test for the first time the level-1 Track Finder trigger system. The present note describes the results of such measurements, focusing the attention on the efficiency and the noise rate of the trigger systems

Bunched beam test of the CMS drift tubes local muon trigger

The 40 MHz bunched muon beam set up at CERN was used in May 2003 to make a full test of the drift tubes local muon trigger. The main goal of the test was to prove that the integration of the various devices located on a muon chamber was adequately done both on the hardware and software side of the system. Furthermore the test provided complete information about the general performance of the trigger algorithms in terms of efficiency and noise. Data were collected with the default configuration of the trigger devices and with several alternative configurations at various angles of incidence of the beam. Tests on noise suppression and di-muon trigger capability were performed

Test beam analysis of the first CMS drift tube muon chamber

In October 2001 the first produced CMS Barrel Drift Tube (DT) Muon Chamber was tested at the CERN Gamma Irradiation Facility (GIF) using a muon beam. A Resistive Plate Chamber (RPC) was attached to the top of the DT chamber, and, for the first time, both detectors were operated coupled together. The performance of the DT chamber was studied for several operating conditions, and for gamma rates similar to the ones expected at LHC. In this paper we present the data analysis; the results are considered fully satisfactory