**3. Conclusions**

For the excitation of the *n* = 2 states of hydrogen atoms due to electron impact, we compared the experimental and theoretical ratios of the cross-sections <sup>σ</sup>2s/<sup>σ</sup>2p. We found that this theoretical ratio is systematically higher than the experimental ratio by about 20% (far beyond the experimental error margins) over the entire range of the energies of the incoming electrons used in the experiment by Callaway and McDowell [18].

We suggested that this discrepancy can be explained by the presence of the SFHA in the experimental hydrogen gas. This explanation is based on the fact that, in the experiments, the cross-section σ2s was determined by using the quenching technique—by applying an electric field that mixed the 2s and 2p states, followed by the emission of the Lymanalpha line from the 2p state. However, the SFHA only has s-states, so the quenching technique would not count the excitation of the SFHA in the 2s state and, thus, lead to the underestimation of the experimental cross-section σ2s.

We estimated the share of the SFHA in an experimental hydrogen gas required to eliminate the above discrepancy and found this share to be about the same as the share of the usual hydrogen atoms. Thus, our results constitute the third proof from atomic experiments that the SFHA does exist—this time, from experiments on the excitation of the *n* = 2 states of atomic hydrogen due to electron impact. This is also important because the SFHA is the leading candidate for dark matter (or at least for a part of it).

**Funding:** This research received no external funding.

**Data Availability Statement:** All data is included in the paper.

**Conflicts of Interest:** The author declares no conflict of interest.
