Published 26 March, 2019; last updated 08 March, 2021
None of particle energy, center-of-mass energy nor Lorentz factor achievable by particle accelerators appears to have undergone a discontinuity of more than ten years of progress at previous rates.
This case study is part of AI Impacts’ discontinuous progress investigation.
Our understanding is that key performance metrics for particle accelerators include how much kinetic energy they can generate in particles, how much center-of-mass energy they can create in collisions between particles, and the Lorentz factor they can achieve.
‘Livingston charts’ show progress in particle accelerator efficacy over time, and seem to be common. We took data from a relatively recent and populated one in a slide deck from a Cornell accelerator physics course (see slide 45),3 and extracted data from it, shown in this spreadsheet (see columns ‘year’ and ‘eV’ in tabs ‘Hoffstaetter Hadrons’ and ‘Hoffstaetter Leptons’ for original data).
The standard performance metric in a Livingston chart is ‘energy needed for a particle to hit a stationary proton with the same center of mass energy as the actual collisions in the accelerator’. We are uncertain why this metric is used, though it does allow for comparisons to earlier technology in a way that CM energy does not. We used a Lorentz transform to obtain particle energy, center-of-mass energy, and Lorentz factors from the Livingston chart data.4
Figure 1 shows our data on particle energy over time, also available in our spreadsheet, tab ‘Particle energy’.
Figure 2 shows our data on center-of-mass energy over time, also available in this spreadsheet, tab ‘CM energy’.
According to Wikipedia, ‘The Lorentz factor or Lorentz term is the factor by which time, length, and relativistic mass change for an object while that object is moving.’
This spreadsheet, tab ‘Lorentz factor’, shows our calculated data for progress on Lorentz factors attained over time.
Primary author: Rick Korzekwa
See Rick Korzekwa’s explanation of his calculation of this here: https://docs.google.com/document/d/1Nv-0Jg6lMNobcDbfuruLwA8hYCXiPvq32f3NHz0BCLs/edit?usp=sharing