Although established, the fact that particles do not rotate is neither experimentally shown nor proven. In measurements and in the case of energetic relevance or exchange, the angular momentum is always quantized to a multiple of h/4π or h/2π, while the real unquantized angular momentum might be much lower. Using data that originates from the hadron accelerator CERN in Switzerland, the frequency of the hypothesized self-rotation of protons could be calculated. It is 2072.180437 Hz and hence, unexpectedly low. The spike in the polarizability curve of protons at Q^2 = 0.33 GeV^2, published currently in the journal Nature, together with the rotation frequency calculated using data from CERN, provides reliable evidence that this might be an interference in terms of superposition of the particle wave of the scattered electrons with the rotation wave of the protons at the same energy level, doubling the expected curve value, which, since there are no other possible explanations, proves the existence of a real proton or particle rotation.