Development of gaseous detectors and measurements of underlying events at CMS

Gaseous detectors are used, or being planned to be used, in one or another form in various particle physics experiments. This talk will briefly summarize the work done on three types of gaseous detectors: glass Resistive Plate Chambers (RPCs), Gas Electron Multiplier (GEM) detectors, and Micromegas detectors. As a part of the R&D program for the proposed INO experiment, the fabrication and characterization of the glass RPC detector is carried out. The steadily increasing luminosity of the LHC requires an upgrade of the CMS and ATLAS detectors. During the phase-1 upgrade (2019-2021), the CMS endcap is instrumented with GEM detectors and the ATLAS endcap is instrumented with New Small Wheel, composed of Micromegas detectors. The construction/assembly as well as quality control testing/characterization of GEM and Micromegas detectors are carried out as a part of upgrade projects.

At LHC, the total pp cross-section has the maximum contribution from inelastic interactions, dominated by the low transverse momentum pT processes. Underlying event (UE) measurements constitute one of the ways to study such low pT QCD processes. Results of the UE measurements performed with the data collected by the CMS detector will also be presented.