Eur. Phys. J. C (2008) 56: 449-460
https://doi.org/10.1140/epjc/s10052-008-0674-7

Special Article - Tools for Experiment and Theory

Reconstruction of cosmic and beam-halo muons with the CMS detector

¹ Department of Physics, Purdue University, West Lafayette, IN, USA
² Università di Torino e Sezione dell’INFN, Torino, Italy
³ CIEMAT, Madrid, Spain
⁴ CERN, Geneva, Switzerland
⁵ Physics Institute III A, RWTH Aachen University, Aachen, Germany
⁶ INFN and University of Bologna, Bologna, Italy
⁷ INFN, Legnaro, Italy
⁸ INFN and University of Padova, Padova, Italy
⁹ INFN, Naples, Italy

^* e-mail: chang.liu@cern.ch

Received: 6 February 2008
Revised: 3 July 2008
Published online: 30 July 2008

Abstract

The powerful muon and tracker systems of the CMS detector together with dedicated reconstruction software allow precise and efficient measurement of muon tracks originating from proton-proton collisions. The standard muon reconstruction algorithms, however, are inadequate to deal with muons that do not originate from collisions. This note discusses the design, implementation, and performance results of a dedicated cosmic muon track reconstruction algorithm, which features pattern recognition optimized for muons that are not coming from the interaction point, i.e., cosmic muons and beam-halo muons. To evaluate the performance of the new algorithm, data taken during Cosmic Challenge phases I and II were studied and compared with simulated cosmic data. In addition, a variety of more general topologies of cosmic muons and beam-halo muons were studied using simulated data to demonstrate some key features of the new algorithm.