Performance of the CMS Drift Tube Chambers with Cosmic Rays

TL;DR

This paper evaluates the performance of the CMS drift tube muon system using cosmic ray data, demonstrating high efficiency and resolution, and confirming simulation accuracy during the CMS Cosmic Run at Four Tesla.

Contribution

It provides the first comprehensive performance assessment of the CMS drift tube chambers with cosmic rays, highlighting their high efficiency and resolution capabilities.

Findings

Muon reconstruction efficiency exceeds 99%.

Coordinate resolution for single hits is about 260 microns.

Track direction resolution is approximately 1.8 mrad.

Abstract

Studies of the performance of the CMS drift tube barrel muon system are described, with results based on data collected during the CMS Cosmic Run at Four Tesla. For most of these data, the solenoidal magnet was operated with a central field of 3.8 T. The analysis of data from 246 out of a total of 250 chambers indicates a very good muon reconstruction capability, with a coordinate resolution for a single hit of about 260 microns, and a nearly 100% efficiency for the drift tube cells. The resolution of the track direction measured in the bending plane is about 1.8 mrad, and the efficiency to reconstruct a segment in a single chamber is higher than 99%. The CMS simulation of cosmic rays reproduces well the performance of the barrel muon detector.