Prospects of searches for leptoquarks decaying into top quarks and muons at the HL-LHC

Abstract

The Standard Model of particle physics has been a successful theory in explaining the constituents of matter and the forces governing them (except gravity). However, some theoretical and experimental observations suggest that it’s not a complete theory of nature. Some measurements in B meson decays (such as the ratios R D , R D ∗ and R k ) and the value of muon anomalous magnetic moment, a μ deviate significantly from the Standard Model predictions. These anomalies can be explained through some Beyond Standard Model theories which predict the existence of a hypothesized particle called leptoquark. Leptoquarks can have O(TeV) masses and large couplings to third generation quarks. In this dissertation, we study single and pair-produced scalar leptoquarks, with left and right-handed couplings, that decay to top quarks and muons in 13 TeV proton-proton collisions at the LHC. We utilize HEPTopTagger to detect top quarks in the Monte Carlo event samples generated from Madgraph and passed on to Pythia for showering. Delphes is used to simulate detector effects. To discriminate our signal from the Standard Model background, we apply cuts on various physical quantities and calculate the 5σ discovery reach of the High Luminosity LHC (HL-LHC) at 3000 f b −1 . We find that the HL-LHC discovery reach at 5σ significance for the left-handed scenario is about 2 TeV. For the right-handed scenario, the discovery reach at 5σ is around 1.75 TeV. In the first chapter, we introduce the subject of high energy physics. In chapter two, we give a brief introduction to quantum field theory, the Standard Model of particle physics and some Beyond Standard Model (BSM) theories. Chapter three gives an overview of the experimental setup for our study. In chapter four, we introduce leptoquarks and describe some of its previous searches. Chapter five deals with the analysis of our study. In chapter six, we present the results and conclusions of the study