Motivation of the CMS Muon System Upgrade with Triple-GEM detectors

R Radogna

doi:10.1016/j.nuclphysbps.2015.09.440

Abstract

The CMS collaboration considers upgrading the muon detector in the forward region using a technology of Gas Electron Multiplier (GEM) chambers, which are able to handle the extreme particle rates expected in this region along with a high spatial resolution. This allows to improve tracking and triggering capabilities, resulting in a lower trigger threshold along with redundant muon identification. The contribution will review the status of the GEM project at CMS.

Highlights

The CMS muon detector system [1], as shown in Figure 1, consists of three types of muon detectors: Drift Tubes (DTs) and Cathode Strip Chambers (CSCs) in the barrel and endcaps respectively, Resistive Plate Chambers (RPCs) in both the barrel and the endcaps
The CMS collaboration considers upgrading the muon detector in the forward region using a technology of Gas Electron Multiplier (GEM) chambers, which are able to handle the extreme particle rates expected in this region along with a high spatial resolution
The short lever arm to measure the bending angle in each station affects the muon momentum determination and many low-pT muons that undergo multiple scattering in the muon system and the iron return yoke are misidentified as high-pT tracks, leading to a flattening of the muon trigger rate towards high momenta

Summary

Introduction

The CMS muon detector system [1], as shown in Figure 1, consists of three types of muon detectors: Drift Tubes (DTs) and Cathode Strip Chambers (CSCs) in the barrel and endcaps respectively, Resistive Plate Chambers (RPCs) in both the barrel and the endcaps. The CMS muon detector system [1], as shown, consists of three types of muon detectors: Drift Tubes (DTs) and Cathode Strip Chambers (CSCs) in the barrel and endcaps respectively, Resistive Plate Chambers (RPCs) in both the barrel and the endcaps. It provide robust, redundant and efficient identification and reconstruction of the muons, in addition to trigger capabilities. The presence of additional detector layers in that region could maintain a highly efficient muon trigger with a low pT threshold and improve the muon reconstruction. By measuring the muon bending angle between CSCs and this new detector

The CMS-GEM Project

The GEM technology

Background nature and rates

Impact on trigger

Summary and outlook