The first step In performing the measurements described above, was to study the production of the states using simulated data. This work was done partly in collaboration with theorists, and in the course of this, I improved the theoretical description of the process.
Using this simulation, I then developed a methodology to select the data of interest, and created a fitting algorithms to the extract the signal.
Several terabytes of data had been collected by the LHCb experiment from 2015 to 2018, and this is stored on computers around the world in a distributed data warehouse.
I interrogated this data and filtered it to extract my signals of interest.
Critical to the signal extraction was the use of a sub-detector of the LHCb experiment called HERSCHEL. This little-used sub-detector was particularly important for my analysis but had not been calibrated. Consequently, I spent several months understanding the detector's behaviour and provided calibrations that were not alone necessary for my analysis, but also allowed this detector to be used by several other physics analyses in the LHCb collaboration.
Having produced a cleaned and filtered subset of the data containing my physics signal, I calculated the various efficiencies with which this data was collected. These efficiencies include the original data-taking efficiency with which data was written to disk during proton-proton and proton-lead collisions, as well as the reconstruction efficiency and my selection. From these efficiencies, it was possible to work back and measure the probability of my signal events being produced in the original beam collisions. This quantity, known technically as the cross-section for the process, is what can be compared directly to theory, and which allows us to extract the distribution of quarks and gluons in the nucleon.
The LHCb collaboration consists of about 800 physicists who self-organise into smaller teams, depending on their physics interest. I was appointed convenor of the LHCb QCD/CEP working group, which studies the strong interaction between quarks and gluons and reactions where only one or a few more particles are created.
In order to understand the physics better, to discuss with theory and experimental colleagues, and to disseminate my ideas and results, I participated in 14 workshops and conferences and was involved in the organisation and convenorship of four workshops related to the study of the strong force.
