The proton radius puzzle was an unanswered problem in physics relating to the size of the proton. Historically the proton radius was measured via two independent methods, which converged to a value of about 0.877 femtometres (1 fm = 10−15 m). This value was challenged by a 2010 experiment utilizing a third method, which produced a radius about 5% smaller than this, or 0.842 femtometres. The discrepancy was resolved when research conducted by Hessel et al. confirmed the same radius for 'electronic' hydrogen as well as it's 'muonic' variant.So, they consider it resolved with no theory, no calculation that correlates with or predicts the proton radius.
The Surfer, OM-IV