Fig. 2: Antihydrogen spectra.
From: Precision spectroscopy of the hyperfine components of the 1S–2S transition in antihydrogen
Measured spectra recorded in run 1 (hollow circles) and run 2 (hollow squares) showing both d–d and c–c transitions (note the discontinuous x axis). The frequency-independent background has been subtracted, and both spectra in each run have been normalized to the fitted height of the c–c line in that run. Therefore, the relative heights of the d–d and c–c lines within a run are conserved. The solid lines show the fits using the lineshape function guided by simulation (Methods). The fit shown with a dashed line (run 2, d–d) is not well constrained due to the sparse sampling in the peak region. The peak of this fit extends beyond the displayed vertical range and reaches a maximum value of 3.5 on this scale. The plotted uncertainties are one-standard-deviation counting errors.
