A new L1 trigger algorithm for the HL-LHC upgrade & Search for light Higgs bosons via NMSSM cascade decays at the CMS experiment

Abstract

This thesis describes three different studies conducted within the framework of the Compact Muon Solenoid (CMS) experiment at CERN.

The performance of the CMS experiment at the Large Hadron Collider relies heavily on the accurate calibration of its subdetectors. Among these, the Electromagnetic Calorimeter, made of scintillating crystals, plays the crucial role of measuring the energy of photons and electrons. The transparency of these crystals degrades due to radiation exposure, necessitating frequent corrections to maintain optimal performances. The correction process was improved from Run 2 to Run 3 and is presented here.

Furthermore, this thesis discusses a search for light Higgs bosons in the framework of the Next-to-Minimal Supersymmetric Standard Model. In particular, it focuses on identifying the events characterized by minimal missing transverse momentum, where the light Higgs bosons decay into boosted pairs of b quarks. This work describes the reduction and estimation of the main background sources for this analysis, with particular attention to the tt ̅ background.

Lastly, a new Level 1 trigger algorithm, developed for potential implementation in the CMS experiment for the High-Luminosity Large Hadron Collider era (HL-LHC), is introduced. HL-LHC will see a massive upgrade to the detector with a completely new L1 trigger system. For the first time, tracks will be reconstructed at the L1 trigger. This new algorithm will exploit reconstructed track information enabling the identification of hard interaction vertices.

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Identifiers

ORCID for Giovanna Salvi: orcid.org/0000-0002-2787-1063

ORCID for Stefano Moretti: orcid.org/0000-0002-8601-7246

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