Understanding the Fusion of Bosons
Every collision at the Large Hadron Collider (LHC) generates numerous potential pathways through which particles can interact, resulting in a diverse array of debris observed by researchers. In 2017, David Rousseau, a physicist at IJCLab in Orsay and part of the ATLAS collaboration, tasked his student Aishik Ghosh with enhancing the team’s capability to identify a specific interaction pathway. This pathway is crucial for measuring the characteristics of the Higgs boson, a particle first identified in 2012, which plays a vital role in explaining the mass of all fundamental particles.
Ghosh faced a significant challenge. “When graduate students begin their journey in ATLAS, they often feel like a small cog within a vast, well-coordinated machine comprised of 3,500 physicists, all seemingly in command of their roles,” he remarked.
The pathway Ghosh was assigned to analyze involves several sequential steps. Initially, the two colliding protons emit W bosons, which are associated with the weak nuclear force. These W bosons then merge, transforming into a Higgs boson. Following its formation, the Higgs boson decays into two Z bosons, another type of particle linked to the weak force. Ultimately, these Z bosons decay into leptons, such as electrons, along with their antimatter counterparts, like positrons.
A Feynman diagram depicting the pathway analyzed by Aishik Ghosh.
Credit: ATLAS
Investigations like Ghosh’s are fundamental in probing the properties of the Higgs boson. By accurately measuring the decay time of the Higgs boson, physicists can potentially uncover interactions with new, yet-to-be-discovered particles that are too heavy to be produced directly in the LHC.
Upon embarking on this project, Ghosh anticipated making minor enhancements to the established methodologies. However, he quickly identified a more significant problem: the directive to isolate and detect a single pathway was not as logical as initially thought.
