LC Project Progress

Project Overview

Project Aim

The main aim is to study the properties of the Higgs particle and W W fusion in electron-positron collisions at a linear collider. The project will focus on the direct reconstruction of the H → b bbar decay mode, as this has the highest branching ratio for a Higgs of mass around 120 GeV as discovered at CERN.

Project Interim Report

Final Report

Invariant Mass of Higgs (MC simulated events)

Determined the invariant mass of the reconstructed Higgs boson in the MC simulated events from its two b jets, and its two c jets (from the decay mode of H → c cbar). Suitable Gaussian fits were applied to the invariant mass distributions to find the peak for these decay modes, with suitable errors quantified.

Attached plots:

H → b bbar with Gaussian fit

H → c cbar with Gaussian fit

Project Plan

The aim is to now implement a neural network flavour tagging processor to separate background and signal events, and to find how well the reconstructed particles compare with the “true” underlying particles. I will move on to look at the WW fusion process at a higher centre-of-mass energy and aim to construct a full Higgs cross-section analysis.

Steps:

• Reconstruct H->bb using truth tagging in ZH
• Implement "real" b-tagging and do the same
• Switch to WW fusion and find the H->bb peak there
• Make a WW->H->bb cross-section measurement

Useful Links

• Light Higgs Production and Decays to Pairs of Bottom and Charm Quarks at 3 TeV